Body Size, Extinction Risk and Knowledge Bias in New World Snakes

PubMed Central

Vilela, Bruno; Villalobos, Fabricio; Rodríguez, Miguel Ángel; Terribile, Levi Carina

2014-01-01

Extinction risk and body size have been found to be related in various vertebrate groups, with larger species being more at risk than smaller ones. We checked whether this was also the case for snakes by investigating extinction risk–body size relationships in the New World's Colubroidea species. We used the IUCN Red List risk categories to assign each species to one of two broad levels of threat (Threatened and Non-Threatened) or to identify it as either Data Deficient or Not-Evaluated by the IUCN. We also included the year of description of each species in our analysis as this could affect the level of threat assigned to it (earlier described species had more time to gather information about them, which might have facilitated their evaluation). Also, species detectability could be a function of body size, with larger species tending to be described earlier, which could have an impact in extinction risk–body size relationships. We found a negative relationship between body size and description year, with large-bodied species being described earlier. Description year also varied among risk categories, with Non-Threatened species being described earlier than Threatened species and both species groups earlier than Data Deficient species. On average, Data Deficient species also presented smaller body sizes, while no size differences were detected between Threatened and Non-Threatened species. So it seems that smaller body sizes are related with species detectability, thus potentially affecting both when a species is described (smaller species tend to be described more recently) as well as the amount of information gathered about it (Data Deficient species tend to be smaller). Our data also indicated that if Data Deficient species were to be categorized as Threatened in the future, snake body size and extinction risk would be negatively related, contrasting with the opposite pattern commonly observed in other vertebrate groups. PMID:25409293

Does body size affect a bird's sensitivity to patch size and landscape structure?

USGS Publications Warehouse

Winter, Maiken; Johnson, Douglas H.; Shaffer, Jill A.

2006-01-01

Larger birds are generally more strongly affected by habitat loss and fragmentation than are smaller ones because they require more resources and thus larger habitat patches. Consequently, conservation actions often favor the creation or protection of larger over smaller patches. However, in grassland systems the boundaries between a patch and the surrounding landscape, and thus the perceived size of a patch, can be indistinct. We investigated whether eight grassland bird species with different body sizes perceived variation in patch size and landscape structure in a consistent manner. Data were collected from surveys conducted in 44 patches of northern tallgrass prairie during 1998–2001. The response to patch size was very similar among species regardless of body size (density was little affected by patch size), except in the Greater Prairie-Chicken (Tympanuchus cupido), which showed a threshold effect and was not found in patches smaller than 140 ha. In landscapes containing 0%–30% woody vegetation, smaller species responded more negatively to increases in the percentage of woody vegetation than larger species, but above an apparent threshold of 30%, larger species were not detected. Further analyses revealed that the observed variation in responses to patch size and landscape structure among species was not solely due to body size per se, but to other differences among species. These results indicate that a stringent application of concepts requiring larger habitat patches for larger species appears to limit the number of grassland habitats that can be protected and may not always be the most effective conservation strategy.

Spatial variation in egg size of a top predator: Interplay of body size and environmental factors?

NASA Astrophysics Data System (ADS)

Louzao, Maite; Igual, José M.; Genovart, Meritxell; Forero, Manuela G.; Hobson, Keith A.; Oro, Daniel

2008-09-01

It is expected that nearby populations are constrained by the same ecological features shaping in turn similarity in their ecological traits. Here, we studied the spatio-temporal variability in egg size among local populations of the critically endangered Balearic shearwater Puffinus mauretanicus, a top marine predator endemic to the western Mediterranean region. Specifically we assessed whether this trait was influenced by maternal body size, as an indicator of a genetic component, and feeding ecology (through stable-carbon and nitrogen-isotope measurements), as an indicator of environmental factors. We found that egg size varied among local populations, an unexpected result at such a small spatial scale. Body size differences at the local population level only partially explained such differences. Blood isotope measurements also differed among local populations. Values of δ 15N suggested inter-population differences in trophic level, showing a similar general pattern with egg size, and suggesting a nutritional link between them whereby egg size was affected by differences in feeding resources and/or behaviour. Values of δ 13C suggested that local populations did not differ in foraging habits with respect to benthic- vs. pelagic-based food-webs. Egg size did not vary among years as did breeding performance, suggesting that a differential temporal window could affect both breeding parameters in relation to food availability. The absence of a relationship between breeding performance and egg size suggested that larger eggs might only confer an advantage during harsh conditions. Alternatively parental quality could greatly affect breeding performance. We showed that inter-population differences in egg size could be influenced by both body size and environmental factors.

Size-Dependent Realized Fecundity in Two Lepidopteran Capital Breeders.

PubMed

Rhainds, Marc

2015-08-01

Body size is correlated with potential fecundity in capital breeders, but size-dependent functions of realized fecundity may be impacted by reproductive losses due to mating failure or oviposition time limitations (number of eggs remaining in the abdomen of females at death). Post-mortem assessment of adults collected in the field after natural death represents a sound approach to quantify how body size affects realized fecundity. This approach is used here for two Lepidoptera for which replicated field data are available, the spruce budworm Choristoneura fumiferana Clemens (Tortricidae) and bagworm Metisa plana Walker (Psychidae). Dead female budworms were collected on drop trays placed beneath tree canopies at four locations. Most females had mated during their lifetime (presence of a spermatophore in spermatheca), and body size did not influence mating failure. Oviposition time limitation was the major factor restricting realized fecundity of females, and its incidence was independent of body size at three of the four locations. Both realized and potential fecundity of female budworms increased linearly with body size. Female bagworms are neotenous and reproduce within a bag; hence, parameters related to realized fecundity are unusually tractable. For each of five consecutive generations of bagworms, mating probability increased with body size, so that virgin-dead females were predominantly small, least fecund individuals. The implication of size-dependent reproductive losses are compared for the two organisms in terms of life history theory and population dynamics, with an emphasis on how differential female motility affects the evolutionary and ecological consequences of size-dependent realized fecundity. © Crown copyright 2015.

Declining body size: a third universal response to warming?

PubMed

Gardner, Janet L; Peters, Anne; Kearney, Michael R; Joseph, Leo; Heinsohn, Robert

2011-06-01

A recently documented correlate of anthropogenic climate change involves reductions in body size, the nature and scale of the pattern leading to suggestions of a third universal response to climate warming. Because body size affects thermoregulation and energetics, changing body size has implications for resilience in the face of climate change. A review of recent studies shows heterogeneity in the magnitude and direction of size responses, exposing a need for large-scale phylogenetically controlled comparative analyses of temporal size change. Integrative analyses of museum data combined with new theoretical models of size-dependent thermoregulatory and metabolic responses will increase both understanding of the underlying mechanisms and physiological consequences of size shifts and, therefore, the ability to predict the sensitivities of species to climate change. Copyright © 2011 Elsevier Ltd. All rights reserved.

A statistical test of unbiased evolution of body size in birds.

PubMed

Bokma, Folmer

2002-12-01

Of the approximately 9500 bird species, the vast majority is small-bodied. That is a general feature of evolutionary lineages, also observed for instance in mammals and plants. The avian interspecific body size distribution is right-skewed even on a logarithmic scale. That has previously been interpreted as evidence that body size evolution has been biased. However, a procedure to test for unbiased evolution from the shape of body size distributions was lacking. In the present paper unbiased body size evolution is defined precisely, and a statistical test is developed based on Monte Carlo simulation of unbiased evolution. Application of the test to birds suggests that it is highly unlikely that avian body size evolution has been unbiased as defined. Several possible explanations for this result are discussed. A plausible explanation is that the general model of unbiased evolution assumes that population size and generation time do not affect the evolutionary variability of body size; that is, that micro- and macroevolution are decoupled, which theory suggests is not likely to be the case.

Time-limited environments affect the evolution of egg-body size allometry.

PubMed

Eckerström-Liedholm, Simon; Sowersby, Will; Gonzalez-Voyer, Alejandro; Rogell, Björn

2017-07-01

Initial offspring size is a fundamental component of absolute growth rate, where large offspring will reach a given adult body size faster than smaller offspring. Yet, our knowledge regarding the coevolution between offspring and adult size is limited. In time-constrained environments, organisms need to reproduce at a high rate and reach a reproductive size quickly. To rapidly attain a large adult body size, we hypothesize that, in seasonal habitats, large species are bound to having a large initial size, and consequently, the evolution of egg size will be tightly matched to that of body size, compared to less time-limited systems. We tested this hypothesis in killifishes, and found a significantly steeper allometric relationship between egg and body sizes in annual, compared to nonannual species. We also found higher rates of evolution of egg and body size in annual compared to nonannual species. Our results suggest that time-constrained environments impose strong selection on rapidly reaching a species-specific body size, and reproduce at a high rate, which in turn imposes constraints on the evolution of egg sizes. In combination, these distinct selection pressures result in different relationships between egg and body size among species in time-constrained versus permanent habitats. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Women gaze behaviour in assessing female bodies: the effects of clothing, body size, own body composition and body satisfaction.

PubMed

Cundall, Amelia; Guo, Kun

2017-01-01

Often with minimally clothed figures depicting extreme body sizes, previous studies have shown women tend to gaze at evolutionary determinants of attractiveness when viewing female bodies, possibly for self-evaluation purposes, and their gaze distribution is modulated by own body dissatisfaction level. To explore to what extent women's body-viewing gaze behaviour is affected by clothing type, dress size, subjective measurements of regional body satisfaction and objective measurements of own body composition (e.g., chest size, body mass index, waist-to-hip ratio), in this self-paced body attractiveness and body size judgement experiment, we compared healthy, young women's gaze distributions when viewing female bodies in tight and loose clothing of different dress sizes. In contrast to tight clothing, loose clothing biased gaze away from the waist-hip to the leg region, and subsequently led to enhanced body attractiveness ratings and body size underestimation for larger female bodies, indicating the important role of clothing in mediating women's body perception. When viewing preferred female bodies, women's higher satisfaction of a specific body region was associated with an increased gaze towards neighbouring body areas, implying satisfaction might reduce the need for comparison of confident body parts; furthermore undesirable body composition measurements were correlated with a gaze avoidance process if the construct was less changeable (i.e. chest size) but a gaze comparison process if the region was more changeable (i.e. body mass index, dress size). Clearly, own body satisfaction and body composition measurements had an evident impact on women's body-viewing gaze allocation, possibly through different cognitive processes.

No Effect of Featural Attention on Body Size Aftereffects

PubMed Central

Stephen, Ian D.; Bickersteth, Chloe; Mond, Jonathan; Stevenson, Richard J.; Brooks, Kevin R.

2016-01-01

Prolonged exposure to images of narrow bodies has been shown to induce a perceptual aftereffect, such that observers’ point of subjective normality (PSN) for bodies shifts toward narrower bodies. The converse effect is shown for adaptation to wide bodies. In low-level stimuli, object attention (attention directed to the object) and spatial attention (attention directed to the location of the object) have been shown to increase the magnitude of visual aftereffects, while object-based attention enhances the adaptation effect in faces. It is not known whether featural attention (attention directed to a specific aspect of the object) affects the magnitude of adaptation effects in body stimuli. Here, we manipulate the attention of Caucasian observers to different featural information in body images, by asking them to rate the fatness or sex typicality of male and female bodies manipulated to appear fatter or thinner than average. PSNs for body fatness were taken at baseline and after adaptation, and a change in PSN (ΔPSN) was calculated. A body size adaptation effect was found, with observers who viewed fat bodies showing an increased PSN, and those exposed to thin bodies showing a reduced PSN. However, manipulations of featural attention to body fatness or sex typicality produced equivalent results, suggesting that featural attention may not affect the strength of the body size aftereffect. PMID:27597835

No Effect of Featural Attention on Body Size Aftereffects.

PubMed

Stephen, Ian D; Bickersteth, Chloe; Mond, Jonathan; Stevenson, Richard J; Brooks, Kevin R

2016-01-01

Prolonged exposure to images of narrow bodies has been shown to induce a perceptual aftereffect, such that observers' point of subjective normality (PSN) for bodies shifts toward narrower bodies. The converse effect is shown for adaptation to wide bodies. In low-level stimuli, object attention (attention directed to the object) and spatial attention (attention directed to the location of the object) have been shown to increase the magnitude of visual aftereffects, while object-based attention enhances the adaptation effect in faces. It is not known whether featural attention (attention directed to a specific aspect of the object) affects the magnitude of adaptation effects in body stimuli. Here, we manipulate the attention of Caucasian observers to different featural information in body images, by asking them to rate the fatness or sex typicality of male and female bodies manipulated to appear fatter or thinner than average. PSNs for body fatness were taken at baseline and after adaptation, and a change in PSN (ΔPSN) was calculated. A body size adaptation effect was found, with observers who viewed fat bodies showing an increased PSN, and those exposed to thin bodies showing a reduced PSN. However, manipulations of featural attention to body fatness or sex typicality produced equivalent results, suggesting that featural attention may not affect the strength of the body size aftereffect.

Ontogenetic and evolutionary effects of predation and competition on nine-spined stickleback (Pungitius pungitius) body size.

PubMed

Välimäki, Kaisa; Herczeg, Gábor

2012-07-01

1. Individual- and population-level variation in body size and growth often correlates with many fitness traits. Predation and food availability are expected to affect body size and growth as important agents of both natural selection and phenotypic plasticity. How differences in predation and food availability affect body size/growth during ontogeny in populations adapted to different predation and competition regimes is rarely studied. 2. Nine-spined stickleback (Pungitius pungitius) populations originating from habitats with varying levels of predation and competition are known to be locally adapted to their respective habitats in terms of body size and growth. Here, we studied how different levels of perceived predation risk and competition during ontogeny affect the reaction norms of body size and growth in (i) marine and pond populations adapted to different levels of predation and competition and (ii) different sexes. We reared nine-spined stickleback in a factorial experiment under two levels of perceived predation risk (present/absent) and competition (high/low food supply). 3. We found divergence in the reaction norms at two levels: (i) predation-adapted marine stickleback had stronger reactions to predatory cues than intraspecific competition-adapted pond stickleback, the latter being more sensitive to available food than the marine fish and (ii) females reacting more strongly to the treatments than males. 4. The repeated, habitat-dependent nature of the differences suggests that natural selection is the agent behind the observed patterns. Our results suggest that genetic adaptation to certain environmental factors also involves an increase in the range of expressible phenotypic plasticity. We found support for this phenomenon at two levels: (i) across populations driven by habitat type and (ii) within populations driven by sex. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.

Drought survival and reproduction impose contrasting selection pressures on maximum body size and sexual size dimorphism in a snake, Seminatrix pygaea.

PubMed

Winne, Christopher T; Willson, John D; Whitfield Gibbons, J

2010-04-01

The causes and consequences of body size and sexual size dimorphism (SSD) have been central questions in evolutionary ecology. Two, often opposing selective forces are suspected to act on body size in animals: survival selection and reproductive (fecundity and sexual) selection. We have recently identified a system where a small aquatic snake species (Seminatrix pygaea) is capable of surviving severe droughts by aestivating within dried, isolated wetlands. We tested the hypothesis that the lack of aquatic prey during severe droughts would impose significant survivorship pressures on S. pygaea, and that the largest individuals, particularly females, would be most adversely affected by resource limitation. Our findings suggest that both sexes experience selection against large body size during severe drought when prey resources are limited, as nearly all S. pygaea are absent from the largest size classes and maximum body size and SSD are dramatically reduced following drought. Conversely, strong positive correlations between maternal body size and reproductive success in S. pygaea suggest that females experience fecundity selection for large size during non-drought years. Collectively, our study emphasizes the dynamic interplay between selection pressures that act on body size and supports theoretical predictions about the relationship between body size and survivorship in ectotherms under conditions of resource limitation.

Environmental, biological and anthropogenic effects on grizzly bear body size: temporal and spatial considerations.

PubMed

Nielsen, Scott E; Cattet, Marc R L; Boulanger, John; Cranston, Jerome; McDermid, Greg J; Shafer, Aaron B A; Stenhouse, Gordon B

2013-09-08

Individual body growth is controlled in large part by the spatial and temporal heterogeneity of, and competition for, resources. Grizzly bears (Ursus arctos L.) are an excellent species for studying the effects of resource heterogeneity and maternal effects (i.e. silver spoon) on life history traits such as body size because their habitats are highly variable in space and time. Here, we evaluated influences on body size of grizzly bears in Alberta, Canada by testing six factors that accounted for spatial and temporal heterogeneity in environments during maternal, natal and 'capture' (recent) environments. After accounting for intrinsic biological factors (age, sex), we examined how body size, measured in mass, length and body condition, was influenced by: (a) population density; (b) regional habitat productivity; (c) inter-annual variability in productivity (including silver spoon effects); (d) local habitat quality; (e) human footprint (disturbances); and (f) landscape change. We found sex and age explained the most variance in body mass, condition and length (R(2) from 0.48-0.64). Inter-annual variability in climate the year before and of birth (silver spoon effects) had detectable effects on the three-body size metrics (R(2) from 0.04-0.07); both maternal (year before birth) and natal (year of birth) effects of precipitation and temperature were related with body size. Local heterogeneity in habitat quality also explained variance in body mass and condition (R(2) from 0.01-0.08), while annual rate of landscape change explained additional variance in body length (R(2) of 0.03). Human footprint and population density had no observed effect on body size. These results illustrated that body size patterns of grizzly bears, while largely affected by basic biological characteristics (age and sex), were also influenced by regional environmental gradients the year before, and of, the individual's birth thus illustrating silver spoon effects. The magnitude of the silver spoon effects was on par with the influence of contemporary regional habitat productivity, which showed that both temporal and spatial influences explain in part body size patterns in grizzly bears. Because smaller bears were found in colder and less-productive environments, we hypothesize that warming global temperatures may positively affect body mass of interior bears.

My 'Fat Girl Complex': a preliminary investigation of sexual health and body image in women of size.

PubMed

Satinsky, Sonya; Dennis, Barbara; Reece, Michael; Sanders, Stephanie; Bardzell, Shaowen

2013-01-01

Women of size who inhabit non-normative bodies may have different experiences with body image and sexual health than women of average body size. In this exploratory study, we interviewed four women of size recruited from a larger mixed-methodological study of body image and sexuality. Each woman was interviewed twice on topics of body image, sexuality and sexual health. Reconstructive Horizon Analysis was used to analyse the content of the interviews. Women who expressed that their bodies had inherent personal and social value regardless of size did not articulate connections between body size and their sexual health. However, those women who looked externally for validation of their attractiveness struggled with acceptance of their sexuality and bodies and spoke of ways in which their body size and appearance hindered them from having the sexually healthy lives that they wanted. Findings highlight two important components of women's sexual health as participants related them to body image: the right to pleasure and the right to engage only in wanted sexual activity. Participants described how negative body attitudes affected both of these aspects of their sexual health. Interventions targeting weight-based stigma may offer a means of indirectly promoting sexual health and autonomy in women.

Effects of experimental warming on survival, phenology and morphology of an aquatic insect (Odonata)

PubMed Central

McCauley, Shannon J.; Hammond, John I.; Frances, Dachin N.; Mabry, Karen E.

2014-01-01

1. Organisms can respond to changing climatic conditions in multiple ways including changes in phenology, body size or morphology, and range shifts. Understanding how developmental temperatures affect insect life-history timing and morphology is crucial because body size and morphology affect multiple aspects of life history, including dispersal ability, while phenology can shape population performance and community interactions. 2. We experimentally assessed how developmental temperatures experienced by aquatic larvae affected survival, phenology, and adult morphology of dragonflies (Pachydiplax longipennis). Larvae were reared under 3 environmental temperatures: ambient, +2.5 °C, and +5 °C, corresponding to temperature projections for our study area 50 and 100 years in the future, respectively. Experimental temperature treatments tracked naturally-occurring variation. 3. We found clear effects of temperature in the rearing environment on survival and phenology: dragonflies reared at the highest temperatures had the lowest survival rates, and emerged from the larval stage approximately 3 weeks earlier than animals reared at ambient temperatures. There was no effect of rearing temperature on overall body size. Although neither the relative wing nor thorax size was affected by warming, a non-significant trend towards an interaction between sex and warming in relative thorax size suggests that males may be more sensitive to warming than females, a pattern that should be investigated further. 4. Warming strongly affected survival in the larval stage and the phenology of adult emergence. Understanding how warming in the developmental environment affects later life-history stages is critical to interpreting the consequences of warming for organismal performance. PMID:26028806

Altitudinal variation in age and body size in Yunnan pond frog (Pelophylax pleuraden).

PubMed

Lou, Shang Ling; Jin, Long; Liu, Yan Hong; Mi, Zhi Ping; Tao, Gang; Tang, Yu Mei; Liao, Wen Bo

2012-08-01

Large-scale systematic patterns of body size are a basic concern of evolutionary biology. Identifying body size variation along altitudinal gradients may help us to understand the evolution of life history of animals. In this study, we investigated altitudinal variation in body size, age and growth rate in Chinese endemic frog, Pelophylax pleuraden. Data sampled from five populations covering an altitudinal span of 1413 to 1935 m in Sichuan province revealed that body size from five populations did not co-vary with altitudes, not following Bergmann's rule. Average adult SVL differed significantly among populations in males, but not in females. For both sexes, average adult age differed significantly among populations. Post-metamorphic growth rate did not co-vary with altitude, and females grew faster than males in all populations. When controlling the effect of age, body size did not differ among populations in both sexes, suggesting that age did not affect variation in body size among populations. For females, there may be other factors, such as the allocation of energy between growth and reproduction, that eliminated the effect of age on body size. To our minds, the major reason of body size variation among populations in male frogs may be related to individual longevity. Our findings also suggest that factors other than age and growth rate may contribute to size differences among populations.

An anatomic study of nipple position and areola size in Asian men.

PubMed

Kasai, Shogo; Shimizu, Yusuke; Nagasao, Tomohisa; Ohnishi, Fumio; Minabe, Toshiharu; Momosawa, Akira; Kishi, Kazuo

2015-02-01

In planning gender-reassignment surgery for biological women and treating men with gynecomastia, surgeons must have a thorough understanding of anatomically correct nipple positions and appropriate areola sizes in men. The authors sought to determine whether body height or body mass index (BMI) affects nipple position or areola size in men. Anatomic measurements of the nipples and areolae of 50 Japanese men were obtained. A relative coordinate system was defined, where the medial-lateral and superior-inferior positions of the nipple were quantitatively indicated by distance ratios between anatomic landmarks. Nipple positions were evaluated for each patient by referring to this coordinate system, and the positions were compared between groups categorized by body height or BMI. Nipple position was not significantly affected by body height. However, the nipple tended to be located more laterally in participants with higher BMI. The vertical nipple position differed between standing and supine positions. Tall men had larger areolae than short men; however, areola size did not differ with respect to BMI. Nipple position and areola size vary by body shape. Consideration of the differences is recommended when performing procedures such as female-to-male gender-reassignment surgery or correction of gynecomastia. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

The temperature size rule in arthropods: independent of macro-environmental variables but size dependent.

PubMed

Klok, C Jaco; Harrison, Jon F

2013-10-01

Temperature is a key factor that affects the rates of growth and development in animals, which ultimately determine body size. Although not universal, a widely documented and poorly understood pattern is the inverse relationship between the temperature at which an ectothermic animal is reared and its body size (temperature size rule [TSR]). The proximate and ultimate mechanisms for the TSR remain unclear. To explore possible explanations for the TSR, we tested for correlations between the magnitude/direction of the TSR and latitude, temperature, elevation, habitat, availability of oxygen, capacity for flight, and taxonomic grouping in 98 species/populations of arthropods. The magnitude and direction of the TSR was not correlated with any of the macro-environmental variables we examined, supporting the generality of the TSR. However, body size affected the magnitude and direction of the TSR, with smaller arthropods more likely to demonstrate a classic TSR. Considerable variation among species exists in the TSR, suggesting either strong interactions with nutrition, or selection based on microclimatic or seasonal variation not captured in classic macro-environmental variables.

Mammalian Collection on Noah's Ark: The Effects of Beauty, Brain and Body Size

PubMed Central

Frynta, Daniel; Šimková, Olga; Lišková, Silvie; Landová, Eva

2013-01-01

The importance of today's zoological gardens as the so-called “Noah's Ark” grows as the natural habitat of many species quickly diminishes. Their potential to shelter a large amount of individuals from many species gives us the opportunity to reintroduce a species that disappeared in nature. However, the selection of animals to be kept in zoos worldwide is highly selective and depends on human decisions driven by both ecological criteria such as population size or vulnerability and audience-driven criteria such as aesthetic preferences. Thus we focused our study on the most commonly kept and bred animal class, the mammals, and we asked which factors affect various aspects of the mammalian collection of zoos. We analyzed the presence/absence, population size, and frequency per species of each of the 123 mammalian families kept in the worldwide zoo collection. Our aim was to explain these data using the human-perceived attractiveness of mammalian families, their body weight, relative brain size and species richness of the family. In agreement with various previous studies, we found that the body size and the attractiveness of mammals significantly affect all studied components of the mammalian collection of zoos. There is a higher probability of the large and attractive families to be kept. Once kept, these animals are presented in larger numbers in more zoos. On the contrary, the relative mean brain size only affects the primary selection whether to keep the family or not. It does not affect the zoo population size or the number of zoos that keep the family. PMID:23690985

Mammalian collection on Noah's Ark: the effects of beauty, brain and body size.

PubMed

Frynta, Daniel; Šimková, Olga; Lišková, Silvie; Landová, Eva

2013-01-01

The importance of today's zoological gardens as the so-called "Noah's Ark" grows as the natural habitat of many species quickly diminishes. Their potential to shelter a large amount of individuals from many species gives us the opportunity to reintroduce a species that disappeared in nature. However, the selection of animals to be kept in zoos worldwide is highly selective and depends on human decisions driven by both ecological criteria such as population size or vulnerability and audience-driven criteria such as aesthetic preferences. Thus we focused our study on the most commonly kept and bred animal class, the mammals, and we asked which factors affect various aspects of the mammalian collection of zoos. We analyzed the presence/absence, population size, and frequency per species of each of the 123 mammalian families kept in the worldwide zoo collection. Our aim was to explain these data using the human-perceived attractiveness of mammalian families, their body weight, relative brain size and species richness of the family. In agreement with various previous studies, we found that the body size and the attractiveness of mammals significantly affect all studied components of the mammalian collection of zoos. There is a higher probability of the large and attractive families to be kept. Once kept, these animals are presented in larger numbers in more zoos. On the contrary, the relative mean brain size only affects the primary selection whether to keep the family or not. It does not affect the zoo population size or the number of zoos that keep the family.

Temporal Trends in Vertebral Size and Shape from Medieval to Modern-Day

PubMed Central

Junno, Juho-Antti; Niskanen, Markku; Nieminen, Miika T.; Maijanen, Heli; Niinimäki, Jaakko; Bloigu, Risto; Tuukkanen, Juha

2009-01-01

Human lumbar vertebrae support the weight of the upper body. Loads lifted and carried by the upper extremities cause significant loading stress to the vertebral bodies. It is well established that trauma-induced vertebral fractures are common especially among elderly people. The aim of this study was to investigate the morphological factors that could have affected the prevalence of trauma-related vertebral fractures from medieval times to the present day. To determine if morphological differences existed in the size and shape of the vertebral body between medieval times and the present day, the vertebral body size and shape was measured from the 4th lumbar vertebra using magnetic resonance imaging (MRI) and standard osteometric calipers. The modern samples consisted of modern Finns and the medieval samples were from archaeological collections in Sweden and Britain. The results show that the shape and size of the 4th lumbar vertebra has changed significantly from medieval times in a way that markedly affects the biomechanical characteristics of the lumbar vertebral column. These changes may have influenced the incidence of trauma- induced spinal fractures in modern populations. PMID:19279681

GI Joe or Average Joe? The impact of average-size and muscular male fashion models on men's and women's body image and advertisement effectiveness.

PubMed

Diedrichs, Phillippa C; Lee, Christina

2010-06-01

Increasing body size and shape diversity in media imagery may promote positive body image. While research has largely focused on female models and women's body image, men may also be affected by unrealistic images. We examined the impact of average-size and muscular male fashion models on men's and women's body image and perceived advertisement effectiveness. A sample of 330 men and 289 women viewed one of four advertisement conditions: no models, muscular, average-slim or average-large models. Men and women rated average-size models as equally effective in advertisements as muscular models. For men, exposure to average-size models was associated with more positive body image in comparison to viewing no models, but no difference was found in comparison to muscular models. Similar results were found for women. Internalisation of beauty ideals did not moderate these effects. These findings suggest that average-size male models can promote positive body image and appeal to consumers. 2010 Elsevier Ltd. All rights reserved.

Weight information labels on media models reduce body dissatisfaction in adolescent girls.

PubMed

Veldhuis, Jolanda; Konijn, Elly A; Seidell, Jacob C

2012-06-01

To examine how weight information labels on variously sized media models affect (pre)adolescent girls' body perceptions and how they compare themselves with media models. We used a three (body shape: extremely thin vs. thin vs. normal weight) × three (information label: 6-kg underweight vs. 3-kg underweight vs. normal weight) experimental design in three age-groups (9-10 years, 12-13 years, and 15-16 years; n = 184). The girls completed questionnaires after exposure to media models. Weight information labels affected girls' body dissatisfaction, social comparison with media figures, and objectified body consciousness. Respondents exposed to an extremely thin body shape labeled to be of "normal weight" were most dissatisfied with their own bodies and showed highest levels of objectified body consciousness and comparison with media figures. An extremely thin body shape combined with a corresponding label (i.e., 6-kg underweight), however, induced less body dissatisfaction and less comparison with the media model. Age differences were also found to affect body perceptions: adolescent girls showed more negative body perceptions than preadolescents. Weight information labels may counteract the generally media-induced thin-body ideal. That is, when the weight labels appropriately informed the respondents about the actual thinness of the media model's body shape, girls were less affected. Weight information labels also instigated a normalization effect when a "normal-weight" label was attached to underweight-sized media models. Presenting underweight as a normal body shape, clearly increased body dissatisfaction in girls. Results also suggest age between preadolescence and adolescence as a critical criterion in responding to media models' body shape. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Scaling of number, size, and metabolic rate of cells with body size in mammals.

PubMed

Savage, Van M; Allen, Andrew P; Brown, James H; Gillooly, James F; Herman, Alexander B; Woodruff, William H; West, Geoffrey B

2007-03-13

The size and metabolic rate of cells affect processes from the molecular to the organismal level. We present a quantitative, theoretical framework for studying relationships among cell volume, cellular metabolic rate, body size, and whole-organism metabolic rate that helps reveal the feedback between these levels of organization. We use this framework to show that average cell volume and average cellular metabolic rate cannot both remain constant with changes in body size because of the well known body-size dependence of whole-organism metabolic rate. Based on empirical data compiled for 18 cell types in mammals, we find that many cell types, including erythrocytes, hepatocytes, fibroblasts, and epithelial cells, follow a strategy in which cellular metabolic rate is body size dependent and cell volume is body size invariant. We suggest that this scaling holds for all quickly dividing cells, and conversely, that slowly dividing cells are expected to follow a strategy in which cell volume is body size dependent and cellular metabolic rate is roughly invariant with body size. Data for slowly dividing neurons and adipocytes show that cell volume does indeed scale with body size. From these results, we argue that the particular strategy followed depends on the structural and functional properties of the cell type. We also discuss consequences of these two strategies for cell number and capillary densities. Our results and conceptual framework emphasize fundamental constraints that link the structure and function of cells to that of whole organisms.

Canalization of body size matters for lifetime reproductive success of male predatory mites (Acari: Phytoseiidae).

PubMed

Walzer, Andreas; Schausberger, Peter

2014-04-01

The adaptive canalization hypothesis predicts that highly fitness-relevant traits are canalized via past selection, resulting in low phenotypic plasticity and high robustness to environmental stress. Accordingly, we hypothesized that the level of phenotypic plasticity of male body size of the predatory mites Phytoseiulus persimilis (low plasticity) and Neoseiulus californicus (high plasticity) reflects the effects of body size variation on fitness, especially male lifetime reproductive success (LRS). We first generated small and standard-sized males of P. persimilis and N. californicus by rearing them to adulthood under limited and ample prey supply, respectively. Then, adult small and standard-sized males were provided with surplus virgin females throughout life to assess their mating and reproductive traits. Small male body size did not affect male longevity or the number of fertilized females but reduced male LRS of P. persimilis but not N. californicus . Proximately, the lower LRS of small than standard-sized P. persimilis males correlated with shorter mating durations, probably decreasing the amount of transferred sperm. Ultimately, we suggest that male body size is more strongly canalized in P. persimilis than N. californicus because deviation from standard body size has larger detrimental fitness effects in P. persimilis than N. californicus .

The Role of Individual Traits and Environmental Factors for Diet Composition of Sheep

PubMed Central

Mysterud, Atle; Austrheim, Gunnar

2016-01-01

Large herbivore consumption of forage is known to affect vegetation composition and thereby ecosystem functions. It is thus important to understand how diet composition arises as a mixture of individual variation in preferences and environmental drivers of availability, but few studies have quantified both. Based on 10 years of data on diet composition by aid of microhistological analysis for sheep kept at high and low population density, we analysed how both individual traits (sex, age, body mass, litter size) linked to preference and environmental variation (density, climate proxies) linked to forage availability affected proportional intake of herbs (high quality/low availability) and Avenella flexuosa (lower quality/high availability). Environmental factors affecting current forage availability such as population density and seasonal and annual variation in diet had the most marked impact on diet composition. Previous environment of sheep (switch between high and low population density) had no impact on diet, suggesting a comparably minor role of learning for density dependent diet selection. For individual traits, only the difference between lambs and ewes affected proportion of A. flexuosa, while body mass better predicted proportion of herbs in diet. Neither sex, body mass, litter size, ewe age nor mass of ewe affected diet composition of lambs, and there was no effect of age, body mass or litter size on diet composition of ewes. Our study highlights that diet composition arises from a combination of preferences being predicted by lamb and ewes’ age and/or body mass differences, and the immediate environment in terms of population density and proxies for vegetation development. PMID:26731411

A National Census of Birth Weight in Purebred Dogs in Italy

PubMed Central

Groppetti, Debora; Pecile, Alessandro; Palestrini, Clara; Marelli, Stefano P.; Boracchi, Patrizia

2017-01-01

Simple Summary Birth weight is a key factor for neonatal mortality and morbidity in most mammalian species. The great morphological variability in size, body weight and breed, as well as in skeletal and cranial conformation makes it challenging to define birth weight standards in dogs. A total of 3293 purebred pups were surveyed to study which maternal aspects can determine birth weight considering head and body shape, size, body weight and breed in bitches, as well as litter size and sex in pups. In our sample, multivariate analysis outcomes suggested that birth weight and litter size were directly proportional to maternal size. The maternal body shape influenced both birth weight and litter size, whereas the maternal head shape had impact only on birth weight. Sex differences in birth weight were found. Birth weight and litter size also varied among breeds. The results of the present study could have practical implications allowing one to identify pups in need of admission to intensive nursing care, as occurs in humans. A deeper knowledge of the factors that significantly influence birth weight could positively affect the canine breeding management helping to prevent and reduce neonatal mortality. Abstract Despite increasing professionalism in dog breeding, the physiological range of birth weight in this species remains unclear. Low birth weight can predispose to neonatal mortality and growth deficiencies in humans. To date, the influence of the morphotype on birth weight has never been studied in dogs. For this purpose, an Italian census of birth weight was collected from 3293 purebred pups based on maternal morphotype, size, body weight and breed, as well as on litter size and sex of pups. Multivariate analysis outcomes showed that birth weight (p < 0.001) and litter size (p < 0.05) increased with maternal size and body weight. Birth weight was also influenced by the maternal head and body shape, with brachycephalic and brachymorph dogs showing the heaviest and the lightest pups, respectively (p < 0.001). Birth weight decreased with litter size (p < 0.001), and male pups were heavier than females (p < 0.001). These results suggest that canine morphotype, not only maternal size and body weight, can affect birth weight and litter size with possible practical implications in neonatal assistance. PMID:28556821

How much does what you eat matter? The potential role of meal size, fat content, and gender on ratings of desirability.

PubMed

Yantcheva, B; Brindal, E

2013-08-01

This study examined how the amount and type of food that a person eats affects perceptions of their personal desirability, femininity/masculinity, and body size while accounting for any assumed similarity biases. Female students (18 to 59 years old) were recruited through the School of Psychology at the University of Adelaide. Participants (n = 191) rated the characteristics of a fictional person based on information in a personal profile. Profiles were identical aside from experimental manipulations of gender (male/female), meal size (small/large) and meal type (regular fat/high fat) with meal manipulations calculated using nutrient recommendations. Ratings of desirability and body size were affected primarily by meal type with targets described as eating a regular fat meal seen as more desirable (M = 5.40, SD = 0.56) and thinner (M = 3.93, SD = 1.05) than those having a high fat meal (M = 5.09, SD = 0.66; M = 4.29, SD = 1.04) (p = .001). Meal size manipulations affected only ratings of body size with larger meals (M = 4.25, SD = 0.88) resulting in higher ratings relative to smaller meals (M = 3.96, SD = 1.20) (p = .036). Despite a suggestion of interactions between target gender and both meal characteristics for ratings of femininity/masculinity in our results, post-hoc analyses largely failed to reveal any pairwise differences. Perceived similarity to the target did relate to levels of desirability (p = .006), and self-esteem positively associated with ratings of target body size (p = .010). Even though men's perceptions of eating behaviours were not reported in this paper, these findings have implications for a better understanding of social pressures faced not only by women, but also for men, as potentially both genders may be affected by eating norms regarding the healthiness of a meal. Copyright © 2013 Elsevier Ltd. All rights reserved.

Seeing the Body Distorts Tactile Size Perception

ERIC Educational Resources Information Center

Longo, Matthew R.; Sadibolova, Renata

2013-01-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of…

A Virtual Reality Full Body Illusion Improves Body Image Disturbance in Anorexia Nervosa.

PubMed

Keizer, Anouk; van Elburg, Annemarie; Helms, Rossa; Dijkerman, H Chris

2016-01-01

Patients with anorexia nervosa (AN) have a persistent distorted experience of the size of their body. Previously we found that the Rubber Hand Illusion improves hand size estimation in this group. Here we investigated whether a Full Body Illusion (FBI) affects body size estimation of body parts more emotionally salient than the hand. In the FBI, analogue to the RHI, participants experience ownership over an entire virtual body in VR after synchronous visuo-tactile stimulation of the actual and virtual body. We asked participants to estimate their body size (shoulders, abdomen, hips) before the FBI was induced, directly after induction and at ~2 hour 45 minutes follow-up. The results showed that AN patients (N = 30) decrease the overestimation of their shoulders, abdomen and hips directly after the FBI was induced. This effect was strongest for estimates of circumference, and also observed in the asynchronous control condition of the illusion. Moreover, at follow-up, the improvements in body size estimation could still be observed in the AN group. Notably, the HC group (N = 29) also showed changes in body size estimation after the FBI, but the effect showed a different pattern than that of the AN group. The results lead us to conclude that the disturbed experience of body size in AN is flexible and can be changed, even for highly emotional body parts. As such this study offers novel starting points from which new interventions for body image disturbance in AN can be developed.

Attention biases in preoccupation with body image: An ERP study of the role of social comparison and automaticity when processing body size.

PubMed

Uusberg, Helen; Peet, Krista; Uusberg, Andero; Akkermann, Kirsti

2018-03-17

Appearance-related attention biases are thought to contribute to body image disturbances. We investigated how preoccupation with body image is associated with attention biases to body size, focusing on the role of social comparison processes and automaticity. Thirty-six women varying on self-reported preoccupation compared their actual body size to size-modified images of either themselves or a figure-matched peer. Amplification of earlier (N170, P2) and later (P3, LPP) ERP components recorded under low vs. high concurrent working memory load were analyzed. Women with high preoccupation exhibited an earlier bias to larger bodies of both self and peer. During later processing stages, they exhibited a stronger bias to enlarged as well as reduced self-images and a lack of sensitivity to size-modifications of the peer-image. Working memory load did not affect these biases systematically. Current findings suggest that preoccupation with body image involves an earlier attention bias to weight increase cues and later over-engagement with own figure. Copyright © 2018 Elsevier B.V. All rights reserved.

The morphology of human hyoid bone in relation to sex, age and body proportions.

PubMed

Urbanová, P; Hejna, P; Zátopková, L; Šafr, M

2013-06-01

Morphological aspects of the human hyoid bone are, like many other skeletal elements in human body, greatly affected by individual's sex, age and body proportions. Still, the known sex-dependent bimodality of a number of body size characteristics overshadows the true within-group patterns. Given the ambiguity of the causal effects of age, sex and body size upon hyoid morphology the present study puts the relationship between shape of human hyoid bone and body proportions (height and weight) under scrutiny of a morphological study. Using 211 hyoid bones and landmark-based methods of geometric morphometrics, it was shown that the size of hyoid bones correlated positively with measured body dimensions but showed no correlation if the individual's sex was controlled for. For shape variables, our results revealed that hyoid morphology is clearly related to body size as expressed in terms of the height and weight. Yet, the hyoid shape was shown to result primarily from the sex-related bimodal distribution of studied body size descriptors which, in the case of the height-dependent model, exhibited opposite trends for males and females. Apart from the global hyoid shape given by spatial arrangements of the greater horns, body size dependency was translated into size and position of the hyoid body. None of the body size characters had any impact on hyoid asymmetry. Ultimately, sexually dimorphic variation was revealed for age-dependent changes in both size and shape of hyoid bones as male hyoids tend to be more susceptible to modifications with age than female bones. Copyright © 2013 Elsevier GmbH. All rights reserved.

Fathers matter: male body mass affects life-history traits in a size-dimorphic seabird

PubMed Central

Jenouvrier, Stéphanie; Börger, Luca; Weimerskirch, Henri; Ozgul, Arpat

2017-01-01

One of the predicted consequences of climate change is a shift in body mass distributions within animal populations. Yet body mass, an important component of the physiological state of an organism, can affect key life-history traits and consequently population dynamics. Over the past decades, the wandering albatross—a pelagic seabird providing bi-parental care with marked sexual size dimorphism—has exhibited an increase in average body mass and breeding success in parallel with experiencing increasing wind speeds. To assess the impact of these changes, we examined how body mass affects five key life-history traits at the individual level: adult survival, breeding probability, breeding success, chick mass and juvenile survival. We found that male mass impacted all traits examined except breeding probability, whereas female mass affected none. Adult male survival increased with increasing mass. Increasing adult male mass increased breeding success and mass of sons but not of daughters. Juvenile male survival increased with their chick mass. These results suggest that a higher investment in sons by fathers can increase their inclusive fitness, which is not the case for daughters. Our study highlights sex-specific differences in the effect of body mass on the life history of a monogamous species with bi-parental care. PMID:28469021

National and regional comparisons between Strahler order and stream size

EPA Science Inventory

Water body size is one of the most important factors affecting the structure and function of aquatic ecosystems. The categorical variable, Strahler stream order, is frequently used as an indirect estimate of stream size. Other indirect estimates of stream size, such as catchmen...

Body size and meta-community structure: the allometric scaling of parasitic worm communities in their mammalian hosts.

PubMed

DE Leo, Giulio A; Dobson, Andrew P; Gatto, Marino

2016-06-01

In this paper we derive from first principles the expected body sizes of the parasite communities that can coexist in a mammal of given body size. We use a mixture of mathematical models and known allometric relationships to examine whether host and parasite life histories constrain the diversity of parasite species that can coexist in the population of any host species. The model consists of one differential equation for each parasite species and a single density-dependent nonlinear equation for the affected host under the assumption of exploitation competition. We derive threshold conditions for the coexistence and competitive exclusion of parasite species using invasion criteria and stability analysis of the resulting equilibria. These results are then used to evaluate the range of parasites species that can invade and establish in a target host and identify the 'optimal' size of a parasite species for a host of a given body size; 'optimal' is defined as the body size of a parasite species that cannot be outcompeted by any other parasite species. The expected distributions of parasites body sizes in hosts of different sizes are then compared with those observed in empirical studies. Our analysis predicts the relative abundance of parasites of different size that establish in the host and suggests that increasing the ratio of parasite body size to host body size above a minimum threshold increases the persistence of the parasite population.

Little effect of climate change on body size of herbivorous beetles.

PubMed

Baar, Yuval; Friedman, Ariel Leib Leonid; Meiri, Shai; Scharf, Inon

2018-04-01

Ongoing climate change affects various aspects of an animal's life, with important effects on distribution range and phenology. The relationship between global warming and body size changes in mammals and birds has been widely studied, with most findings indicating a decline in body size over time. Nevertheless, little data exist on similar size change patterns of invertebrates in general and insects in particular, and it is unclear whether insects should decrease in size or not with climate warming. We measured over 4000 beetle specimens, belonging to 29 beetle species in 8 families, collected in Israel during the last 100 years. The sampled species are all herbivorous. We examined whether beetle body size had changed over the years, while also investigating the relationships between body size and annual temperature, precipitation, net primary productivity (NPP) at the collection site and collection month. None of the environmental variables, including the collection year, was correlated with the size of most of the studied beetle species, while there were strong interactions of all variables with species. Our results, though mostly negative, suggest that the effect of climate change on insect body size is species-specific and by no means a general macro-ecological rule. They also suggest that the intrapopulation variance in body size of insects collected as adults in the field is large enough to conceal intersite environmental effects on body size, such as the effect of temperature and NPP. © 2016 Institute of Zoology, Chinese Academy of Sciences.

The effect of body coloration and group size on social partner preferences in female fighting fish (Betta splendens).

PubMed

Blakeslee, C; McRobert, S P; Brown, A C; Clotfelter, E D

2009-02-01

Females of the fighting fish Betta splendens have been shown to associate with other B. splendens females in a manner reminiscent of shoaling behavior. Since body coloration varies dramatically in this species, and since body coloration has been shown to affect shoalmate choice in other species of fish, we examined the influence of body coloration on association preferences in female B. splendens. In dichotomous choice tests, B. splendens females spent more time swimming near groups of females (regardless of coloration) than swimming near an empty chamber, and chose to swim near fish of similar coloration to their own when choosing between two distinctly colored groups of females. When examining the interplay between body coloration and group size, focal fish spent more time swimming near larger groups (N=5) of similarly colored fish than swimming near an individual female of similar coloration. However, focal fish showed no preference when presented with an individual female of similar coloration and a larger group of females of dissimilar coloration. These results suggest that association choices in B. splendens females are strongly affected by both body coloration and by group size.

Spatial variation in abiotic and biotic factors in a floodplain determine anuran body size and growth rate at metamorphosis.

PubMed

Indermaur, Lukas; Schmidt, Benedikt R; Tockner, Klement; Schaub, Michael

2010-07-01

Body size at metamorphosis is a critical trait in the life history of amphibians. Despite the wide-spread use of amphibians as experimental model organisms, there is a limited understanding of how multiple abiotic and biotic factors affect the variation in metamorphic traits under natural conditions. The aim of our study was to quantify the effects of abiotic and biotic factors on spatial variation in the body size of tadpoles and size at metamorphosis of the European common toad (Bufo b. spinosus). Our study population was distributed over the riverbed (active tract) and the fringing riparian forest of a natural floodplain. The riverbed had warm ponds with variable hydroperiod and few predators, whereas the forest had ponds with the opposite characteristics. Spatial variation in body size at metamorphosis was governed by the interactive effects of abiotic and biotic factors. The particular form of the interaction between water temperature and intraspecific tadpole density suggests that abiotic factors laid the foundation for biotic factors: intraspecific density decreased growth only at high temperature. Predation and intraspecific density jointly reduced metamorphic size. Interspecific density had a negligible affect on body size at metamorphosis, suggesting weak inter-anuran interactions in the larval stage. Population density at metamorphosis was about one to two orders of magnitudes higher in the riverbed ponds than in the forest ponds, mainly because of lower tadpole mortality. Based on our results, we conclude that ponds in the riverbed appear to play a pivotal role for the population because tadpole growth and survival is best in this habitat.

Body size and lower limb posture during walking in humans.

PubMed

Hora, Martin; Soumar, Libor; Pontzer, Herman; Sládek, Vladimír

2017-01-01

We test whether locomotor posture is associated with body mass and lower limb length in humans and explore how body size and posture affect net joint moments during walking. We acquired gait data for 24 females and 25 males using a three-dimensional motion capture system and pressure-measuring insoles. We employed the general linear model and commonality analysis to assess the independent effect of body mass and lower limb length on flexion angles at the hip, knee, and ankle while controlling for sex and velocity. In addition, we used inverse dynamics to model the effect of size and posture on net joint moments. At early stance, body mass has a negative effect on knee flexion (p < 0.01), whereas lower limb length has a negative effect on hip flexion (p < 0.05). Body mass uniquely explains 15.8% of the variance in knee flexion, whereas lower limb length uniquely explains 5.4% of the variance in hip flexion. Both of the detected relationships between body size and posture are consistent with the moment moderating postural adjustments predicted by our model. At late stance, no significant relationship between body size and posture was detected. Humans of greater body size reduce the flexion of the hip and knee at early stance, which results in the moderation of net moments at these joints.

Body size evolution of a shell-brooding cichlid fish from Lake Tanganyika.

PubMed

Takahashi, T; Ota, K

2016-12-01

The substrate-brooding cichlid fish Telmatochromis temporalis in Lake Tanganyika demonstrates a simple example of ecological speciation between normal and dwarf morphs through divergent natural selection on body size. The dwarf morph most likely evolved from the ancestral normal morph; therefore, elucidating the evolution of its small body size is a key to understanding this ecological speciation event. Previous studies suggest that the small body size of the dwarf morph is an adaptation to the use of empty snail shells as shelters (males) and spawning sites (females), but this idea has not been fully evaluated. Combining original and previously published information, this study compared likelihood values to determine the primary factor that would be responsible for regulating the body size of the dwarf morph. Male body size is most likely regulated by the ability to turn within shells, which may influence the predation avoidance of adult fish. Females are smaller than males, and their body size is most likely regulated by the ability to lay eggs in the small spaces within shells close to the shell apices where predation risk on eggs is lower. This study provides new evidence supporting the hypothesis that different natural selection factors affected body size of the different sexes of the dwarf morph, which has not been reported in other animal species. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Which is the Ideal Breast Size?: Some Social Clues for Plastic Surgeons.

PubMed

Raposio, Edoardo; Belgrano, Valerio; Santi, PierLuigi; Chiorri, Carlo

2016-03-01

To provide plastic surgeons with more detailed information as to factors affecting the perception of female attractiveness, the present study was aimed to investigate whether the interaction effect of breast and body size on ratings of female attractiveness is moderated by sociodemographic variables and whether ratings of shapeliness diverge from those of attractiveness.A community sample of 958 Italian participants rated the attractiveness and the shapeliness of 15 stimuli (5 breast sizes × 3 body sizes) in which frontal, 3/4, and profile views of the head and torso of a faceless woman were jointly shown.Bigger breast sizes obtained the highest attractiveness ratings, but the breast-by-body size interaction was also significant. Evidence was found of a moderator role of sex, marital status, and age. When the effects of breast and body size and their interaction had been ruled out, sex differences were at best very slight and limited to very specific combinations of breast and body sizes. Ratings of attractiveness and shapeliness were highly correlated and did not significantly differ.Results suggest that to address women's psychological needs, concerns, and expectations about their appearance, plastic surgeons should not simply focus on breast size but should carefully consider the 'big picture': the body in its entirety.

A Virtual Reality Full Body Illusion Improves Body Image Disturbance in Anorexia Nervosa

PubMed Central

Keizer, Anouk; van Elburg, Annemarie; Helms, Rossa; Dijkerman, H. Chris

2016-01-01

Background Patients with anorexia nervosa (AN) have a persistent distorted experience of the size of their body. Previously we found that the Rubber Hand Illusion improves hand size estimation in this group. Here we investigated whether a Full Body Illusion (FBI) affects body size estimation of body parts more emotionally salient than the hand. In the FBI, analogue to the RHI, participants experience ownership over an entire virtual body in VR after synchronous visuo-tactile stimulation of the actual and virtual body. Methods and Results We asked participants to estimate their body size (shoulders, abdomen, hips) before the FBI was induced, directly after induction and at ~2 hour 45 minutes follow-up. The results showed that AN patients (N = 30) decrease the overestimation of their shoulders, abdomen and hips directly after the FBI was induced. This effect was strongest for estimates of circumference, and also observed in the asynchronous control condition of the illusion. Moreover, at follow-up, the improvements in body size estimation could still be observed in the AN group. Notably, the HC group (N = 29) also showed changes in body size estimation after the FBI, but the effect showed a different pattern than that of the AN group. Conclusion The results lead us to conclude that the disturbed experience of body size in AN is flexible and can be changed, even for highly emotional body parts. As such this study offers novel starting points from which new interventions for body image disturbance in AN can be developed. PMID:27711234

Dispersal capacity and diet breadth modify the response of wild bees to habitat loss.

PubMed

Bommarco, Riccardo; Biesmeijer, Jacobus C; Meyer, Birgit; Potts, Simon G; Pöyry, Juha; Roberts, Stuart P M; Steffan-Dewenter, Ingolf; Ockinger, Erik

2010-07-07

Habitat loss poses a major threat to biodiversity, and species-specific extinction risks are inextricably linked to life-history characteristics. This relationship is still poorly documented for many functionally important taxa, and at larger continental scales. With data from five replicated field studies from three countries, we examined how species richness of wild bees varies with habitat patch size. We hypothesized that the form of this relationship is affected by body size, degree of host plant specialization and sociality. Across all species, we found a positive species-area slope (z = 0.19), and species traits modified this relationship. Large-bodied generalists had a lower z value than small generalists. Contrary to predictions, small specialists had similar or slightly lower z value compared with large specialists, and small generalists also tended to be more strongly affected by habitat loss as compared with small specialists. Social bees were negatively affected by habitat loss (z = 0.11) irrespective of body size. We conclude that habitat loss leads to clear shifts in the species composition of wild bee communities.

Dispersal capacity and diet breadth modify the response of wild bees to habitat loss

PubMed Central

Bommarco, Riccardo; Biesmeijer, Jacobus C.; Meyer, Birgit; Potts, Simon G.; Pöyry, Juha; Roberts, Stuart P. M.; Steffan-Dewenter, Ingolf; Öckinger, Erik

2010-01-01

Habitat loss poses a major threat to biodiversity, and species-specific extinction risks are inextricably linked to life-history characteristics. This relationship is still poorly documented for many functionally important taxa, and at larger continental scales. With data from five replicated field studies from three countries, we examined how species richness of wild bees varies with habitat patch size. We hypothesized that the form of this relationship is affected by body size, degree of host plant specialization and sociality. Across all species, we found a positive species–area slope (z = 0.19), and species traits modified this relationship. Large-bodied generalists had a lower z value than small generalists. Contrary to predictions, small specialists had similar or slightly lower z value compared with large specialists, and small generalists also tended to be more strongly affected by habitat loss as compared with small specialists. Social bees were negatively affected by habitat loss (z = 0.11) irrespective of body size. We conclude that habitat loss leads to clear shifts in the species composition of wild bee communities. PMID:20219735

Cannibalism by damselflies increases with rising temperature

PubMed Central

Kirk, Devin; Shea, Dylan

2017-01-01

Trophic interactions are likely to change under climate warming. These interactions can be altered directly by changing consumption rates, or indirectly by altering growth rates and size asymmetries among individuals that in turn affect feeding. Understanding these processes is particularly important for intraspecific interactions, as direct and indirect changes may exacerbate antagonistic interactions. We examined the effect of temperature on activity rate, growth and intraspecific size asymmetries, and how these temperature dependencies affected cannibalism in Lestes congener, a damselfly with marked intraspecific variation in size. Temperature increased activity rates and exacerbated differences in body size by increasing growth rates. Increased activity and changes in body size interacted to increase cannibalism at higher temperatures. We argue that our results are likely to be general to species with life-history stages that vary in their temperature dependencies, and that the effects of climate change on communities may depend on the temperature dependencies of intraspecific interactions. PMID:28515331

Cannibalism by damselflies increases with rising temperature.

PubMed

Start, Denon; Kirk, Devin; Shea, Dylan; Gilbert, Benjamin

2017-05-01

Trophic interactions are likely to change under climate warming. These interactions can be altered directly by changing consumption rates, or indirectly by altering growth rates and size asymmetries among individuals that in turn affect feeding. Understanding these processes is particularly important for intraspecific interactions, as direct and indirect changes may exacerbate antagonistic interactions. We examined the effect of temperature on activity rate, growth and intraspecific size asymmetries, and how these temperature dependencies affected cannibalism in Lestes congener , a damselfly with marked intraspecific variation in size. Temperature increased activity rates and exacerbated differences in body size by increasing growth rates. Increased activity and changes in body size interacted to increase cannibalism at higher temperatures. We argue that our results are likely to be general to species with life-history stages that vary in their temperature dependencies, and that the effects of climate change on communities may depend on the temperature dependencies of intraspecific interactions. © 2017 The Author(s).

Visual attention mediates the relationship between body satisfaction and susceptibility to the body size adaptation effect.

PubMed

Stephen, Ian D; Sturman, Daniel; Stevenson, Richard J; Mond, Jonathan; Brooks, Kevin R

2018-01-01

Body size misperception-the belief that one is larger or smaller than reality-affects a large and growing segment of the population. Recently, studies have shown that exposure to extreme body stimuli results in a shift in the point of subjective normality, suggesting that visual adaptation may be a mechanism by which body size misperception occurs. Yet, despite being exposed to a similar set of bodies, some individuals within a given geographical area will develop body size misperception and others will not. The reason for these individual difference is currently unknown. One possible explanation stems from the observation that women with lower levels of body satisfaction have been found to pay more attention to images of thin bodies. However, while attention has been shown to enhance visual adaptation effects in low (e.g. rotational and linear motion) and high level stimuli (e.g., facial gender), it is not known whether this effect exists in visual adaptation to body size. Here, we test the hypothesis that there is an indirect effect of body satisfaction on the direction and magnitude of the body fat adaptation effect, mediated via visual attention (i.e., selectively attending to images of thin over fat bodies or vice versa). Significant mediation effects were found in both men and women, suggesting that observers' level of body satisfaction may influence selective visual attention to thin or fat bodies, which in turn influences the magnitude and direction of visual adaptation to body size. This may provide a potential mechanism by which some individuals develop body size misperception-a risk factor for eating disorders, compulsive exercise behaviour and steroid abuse-while others do not.

Visual attention mediates the relationship between body satisfaction and susceptibility to the body size adaptation effect

PubMed Central

Sturman, Daniel; Stevenson, Richard J.; Mond, Jonathan; Brooks, Kevin R.

2018-01-01

Body size misperception–the belief that one is larger or smaller than reality–affects a large and growing segment of the population. Recently, studies have shown that exposure to extreme body stimuli results in a shift in the point of subjective normality, suggesting that visual adaptation may be a mechanism by which body size misperception occurs. Yet, despite being exposed to a similar set of bodies, some individuals within a given geographical area will develop body size misperception and others will not. The reason for these individual difference is currently unknown. One possible explanation stems from the observation that women with lower levels of body satisfaction have been found to pay more attention to images of thin bodies. However, while attention has been shown to enhance visual adaptation effects in low (e.g. rotational and linear motion) and high level stimuli (e.g., facial gender), it is not known whether this effect exists in visual adaptation to body size. Here, we test the hypothesis that there is an indirect effect of body satisfaction on the direction and magnitude of the body fat adaptation effect, mediated via visual attention (i.e., selectively attending to images of thin over fat bodies or vice versa). Significant mediation effects were found in both men and women, suggesting that observers’ level of body satisfaction may influence selective visual attention to thin or fat bodies, which in turn influences the magnitude and direction of visual adaptation to body size. This may provide a potential mechanism by which some individuals develop body size misperception–a risk factor for eating disorders, compulsive exercise behaviour and steroid abuse–while others do not. PMID:29385137

Small body size in an insect shifts development, prior to adult eclosion, towards early reproduction

PubMed Central

Thorne, Ashley D; Pexton, John J; Dytham, Calvin; Mayhew, Peter J

2006-01-01

Life-history theory has suggested that individual body size can strongly affect the allocation of resources to reproduction and away from other traits such as survival. In many insects, adults eclose with a proportion of their potential lifetime egg production that is already mature (the ovigeny index). We establish for the solitary parasitoid wasp Aphaereta genevensis that the ovigeny index decreases with adult body size, despite both initial egg load and potential lifetime fecundity increasing with body size. This outcome is predicted by adaptive models and is the first unequivocal intraspecific demonstration. Evidence suggests that a high ovigeny index carries a cost of reduced longevity in insects. Our results therefore contribute to the emerging evidence that small body size can favour a developmental shift in juveniles that favours early reproduction, but which has adverse late-life consequences. These findings are likely to have important implications for developmental biologists and population biologists. PMID:16600887

Dormancy cues alter insect temperature-size relationships.

PubMed

Clemmensen, Sharon F; Hahn, Daniel A

2015-01-01

Developmental temperatures can have dramatic effects on body size in ectotherms. Thermal plasticity in body size is often viewed in the context of seasonality, but the role of seasonal dormancy responses in generating temperature-size relationships is underappreciated. We used the moth Helicoverpa zea (corn earworm) to examine how photoperiodic seasonal dormancy programming for pupal diapause affects the temperature-size relationship. Specifically, we partition out the contributions of somatic growth versus nutrient storage as fat to the thermal reaction norm for size. With increasing temperature from 16 °C to 20 °C, dormant pupae were both overall larger and progressively fatter than non-dormant pupae. This body mass response is likely driven by concurrent increases in food consumption and longer development times as temperatures increase. Our results demonstrate that seasonal photoperiodic cues can alter temperature-size relationships during pre-dormancy development. For biologists interested in seasonal effects on temperature-size relationships, our results suggest that the key to fully understanding these relationships may lie in integrating multiple seasonal cues and multiple aspects of body size and composition in a nutrient-allocation framework.

Interspecific geographic range size-body size relationship and the diversification dynamics of Neotropical furnariid birds.

PubMed

Inostroza-Michael, Oscar; Hernández, Cristián E; Rodríguez-Serrano, Enrique; Avaria-Llautureo, Jorge; Rivadeneira, Marcelo M

2018-05-01

Among the earliest macroecological patterns documented, is the range and body size relationship, characterized by a minimum geographic range size imposed by the species' body size. This boundary for the geographic range size increases linearly with body size and has been proposed to have implications in lineages evolution and conservation. Nevertheless, the macroevolutionary processes involved in the origin of this boundary and its consequences on lineage diversification have been poorly explored. We evaluate the macroevolutionary consequences of the difference (hereafter the distance) between the observed and the minimum range sizes required by the species' body size, to untangle its role on the diversification of a Neotropical species-rich bird clade using trait-dependent diversification models. We show that speciation rate is a positive hump-shaped function of the distance to the lower boundary. The species with highest and lowest distances to minimum range size had lower speciation rates, while species close to medium distances values had the highest speciation rates. Further, our results suggest that the distance to the minimum range size is a macroevolutionary constraint that affects the diversification process responsible for the origin of this macroecological pattern in a more complex way than previously envisioned. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Body Image and Quality of Life in a Group of African American Women

ERIC Educational Resources Information Center

Cox, Tiffany L.; Zunker, Christie; Wingo, Brooks; Thomas, Dana-Marie; Ard, Jamy D.

2010-01-01

African American (AA) women's preference for a larger body size and underestimation of their body weight may affect the relationship between their body weight and weight-related quality of life (QOL). We wanted to examine the relationship between weight-related QOL and body mass index (BMI) in a sample of overweight AA women. Thirty-three…

as response to seasonal variability

PubMed

Badano, Ernesto I; Labra, Fabio A; Martínez-Pérez, Cecilia G; Vergara, Carlos H

2016-03-01

Ecologists have been largely interested in the description and understanding of the power scaling relationships between body size and abundance of organisms. Many studies have focused on estimating the exponents of these functions across taxonomic groups and spatial scales, to draw inferences about the processes underlying this pattern. The exponents of these functions usually approximate -3/4 at geographical scales, but they deviate from this value when smaller spatial extensions are considered. This has led to propose that body size-abundance relationships at small spatial scales may reflect the impact of environmental changes. This study tests this hypothesis by examining body size spectra of benthic shrimps (Decapoda: Caridea) and snails (Gastropoda) in the Tamiahua lagoon, a brackish body water located in the Eastern coast of Mexico. We mea- sured water quality parameters (dissolved oxygen, salinity, pH, water temperature, sediment organic matter and chemical oxygen demand) and sampled benthic macrofauna during three different climatic conditions of the year (cold, dry and rainy season). Given the small size of most individuals in the benthic macrofaunal samples, we used body volume, instead of weight, to estimate their body size. Body size-abundance relationships of both taxonomic groups were described by tabulating data from each season into base-2 logarithmic body size bins. In both taxonomic groups, observed frequencies per body size class in each season were standardized to yield densities (i.e., individuals/m(3)). Nonlinear regression analyses were separately performed for each taxonomic group at each season to assess whether body size spectra followed power scaling functions. Additionally, for each taxonomic group, multiple regression analyses were used to determine whether these relationships varied among seasons. Our results indicated that, while body size-abundance relationships in both taxonomic groups followed power functions, the parameters defining the shape of these relationships varied among seasons. These variations in the parameters of the body size-abundance relationships seems to be related to changes in the abundance of individuals within the different body size classes, which seems to follow the seasonal changes that occur in the environmental conditions of the lagoon. Thus, we propose that these body size-abundance relation- ships are influenced by the frequency and intensity of environmental changes affecting this ecosystem.

Intra- and Trans-Generational Costs of Reduced Female Body Size Caused by Food Limitation Early in Life in Mites

PubMed Central

Walzer, Andreas; Schausberger, Peter

2013-01-01

Background Food limitation early in life may be compensated for by developmental plasticity resulting in accelerated development enhancing survival at the expense of small adult body size. However and especially for females in non-matching maternal and offspring environments, being smaller than the standard may incur considerable intra- and trans-generational costs. Methodology/Principal Findings Here, we evaluated the costs of small female body size induced by food limitation early in life in the sexually size-dimorphic predatory mite Phytoseiulus persimilis. Females are larger than males. These predators are adapted to exploit ephemeral spider mite prey patches. The intra- and trans-generational effects of small maternal body size manifested in lower maternal survival probabilities, decreased attractiveness for males, and a reduced number and size of eggs compared to standard-sized females. The trans-generational effects of small maternal body size were sex-specific with small mothers producing small daughters but standard-sized sons. Conclusions/Significance Small female body size apparently intensified the well-known costs of sexual activity because mortality of small but not standard-sized females mainly occurred shortly after mating. The disadvantages of small females in mating and egg production may be generally explained by size-associated morphological and physiological constraints. Additionally, size-assortative mate preferences of standard-sized mates may have rendered small females disproportionally unattractive mating partners. We argue that the sex-specific trans-generational effects were due to sexual size dimorphism – females are the larger sex and thus more strongly affected by maternal stress than the smaller males – and to sexually selected lower plasticity of male body size. PMID:24265745

Effect of body size and body mass on δ 13 C and δ 15 N in coastal fishes and cephalopods

NASA Astrophysics Data System (ADS)

Vinagre, C.; Máguas, C.; Cabral, H. N.; Costa, M. J.

2011-11-01

Carbon and nitrogen isotopes have been widely used in the investigation of trophic relations, energy pathways, trophic levels and migrations, under the assumption that δ 13C is independent of body size and that variation in δ 15N occurs exclusively due to ontogenetic changes in diet and not body size increase per se. However, several studies have shown that these assumptions are uncertain. Data from food-webs containing an important number of species lack theoretical support on these assumptions because very few species have been tested for δ 13C and δ 15N variation in captivity. However, if sampling comprises a wide range of body sizes from various species, the variation of δ 13C and δ 15N with body size can be investigated. While correlation between body size and δ 13C and δ 15N can be due to ontogenetic diet shifts, stability in such values throughout the size spectrum can be considered an indication that δ 13C and δ 15N in muscle tissues of such species is independent of body size within that size range, and thus the basic assumptions can be applied in the interpretation of such food webs. The present study investigated the variation in muscle δ 13C and δ 15N with body size and body mass of coastal fishes and cephalopods. It was concluded that muscle δ 13C and δ 15N did not vary with body size or mass for all bony fishes with only one exception, the dragonet Callionymus lyra. Muscle δ 13C and δ 15N also did not vary with body size or mass in cartilaginous fishes and cephalopods, meaning that body size/mass per se have no effect on δ 13C or δ 15N, for most species analysed and within the size ranges sampled. The assumption that δ 13C is independent of body size and that variation in δ 15N is not affected by body size increase per se was upheld for most organisms and can be applied to the coastal food web studied taking into account that C. lyra is an exception.

Body size and lower limb posture during walking in humans

PubMed Central

Hora, Martin; Soumar, Libor; Pontzer, Herman; Sládek, Vladimír

2017-01-01

We test whether locomotor posture is associated with body mass and lower limb length in humans and explore how body size and posture affect net joint moments during walking. We acquired gait data for 24 females and 25 males using a three-dimensional motion capture system and pressure-measuring insoles. We employed the general linear model and commonality analysis to assess the independent effect of body mass and lower limb length on flexion angles at the hip, knee, and ankle while controlling for sex and velocity. In addition, we used inverse dynamics to model the effect of size and posture on net joint moments. At early stance, body mass has a negative effect on knee flexion (p < 0.01), whereas lower limb length has a negative effect on hip flexion (p < 0.05). Body mass uniquely explains 15.8% of the variance in knee flexion, whereas lower limb length uniquely explains 5.4% of the variance in hip flexion. Both of the detected relationships between body size and posture are consistent with the moment moderating postural adjustments predicted by our model. At late stance, no significant relationship between body size and posture was detected. Humans of greater body size reduce the flexion of the hip and knee at early stance, which results in the moderation of net moments at these joints. PMID:28192522

Seasonal patterns of body temperature and microhabitat selection in a lacertid lizard

NASA Astrophysics Data System (ADS)

Ortega, Zaida; Pérez-Mellado, Valentín

2016-11-01

In temperate areas, seasonal changes entail a source of environmental variation potentially important for organisms. Temperate ectotherms may be adapted to the seasonal fluctuations in environmental traits. For lizards, behavioural adaptations regarding microhabitat selection could arise to improve thermoregulation during the different seasons. However, little is still known about which traits influence microhabitat selection of lizards and their adaptation to seasonality. Here we used Podarcis guadarramae to study the role of potential intrinsic (body size, sex, age) and environmental traits (air and substrate temperatures, wind speed, and sunlight) in the seasonal changes of body temperatures and microhabitat selection of lizards. We measured body temperatures of lizards in the same habitat during the four seasons and compared the climatic variables of the microhabitats selected by lizards with the mean climatic conditions available in their habitat. Body temperatures were similar for adult males, adult females, and juveniles within each season, being significantly higher in summer than in the other seasons, and in spring than in winter. The same pattern was found regarding substrate and air temperatures of the selected microhabitats. Wind speed and air temperature did not affect body temperatures, while body length was marginally significant and substrate temperatures and season did affect the body temperatures of lizards. Our results during the whole year support the idea that the seasonality could be the most important factor affecting body temperatures of these temperate species. Regarding microhabitat selection, environmental constraints, as environmental temperatures and wind speed, affected the seasonal changes on behavioural thermoregulation of lizards. This effect was similar between sexes and age classes, and was independent of body size. In addition, importance of sunlight exposure of the selected microhabitats (full sun, filtered sun, or shade) also changed between seasons. Hence, environmental constraints were the main forces driving seasonal changes in microhabitat selection.

Evidence of a chimpanzee-sized ancestor of humans but a gibbon-sized ancestor of apes.

PubMed

Grabowski, Mark; Jungers, William L

2017-10-12

Body mass directly affects how an animal relates to its environment and has a wide range of biological implications. However, little is known about the mass of the last common ancestor (LCA) of humans and chimpanzees, hominids (great apes and humans), or hominoids (all apes and humans), which is needed to evaluate numerous paleobiological hypotheses at and prior to the root of our lineage. Here we use phylogenetic comparative methods and data from primates including humans, fossil hominins, and a wide sample of fossil primates including Miocene apes from Africa, Europe, and Asia to test alternative hypotheses of body mass evolution. Our results suggest, contrary to previous suggestions, that the LCA of all hominoids lived in an environment that favored a gibbon-like size, but a series of selective regime shifts, possibly due to resource availability, led to a decrease and then increase in body mass in early hominins from a chimpanzee-sized LCA.The pattern of body size evolution in hominids can provide insight into historical human ecology. Here, Grabowski and Jungers use comparative phylogenetic analysis to reconstruct the likely size of the ancestor of humans and chimpanzees and the evolutionary history of selection on body size in primates.

Evolution of extreme body size disparity in monitor lizards (Varanus).

PubMed

Collar, David C; Schulte, James A; Losos, Jonathan B

2011-09-01

Many features of species' biology, including life history, physiology, morphology, and ecology are tightly linked to body size. Investigation into the causes of size divergence is therefore critical to understanding the factors shaping phenotypic diversity within clades. In this study, we examined size evolution in monitor lizards (Varanus), a clade that includes the largest extant lizard species, the Komodo dragon (V. komodoensis), as well as diminutive species that are nearly four orders of magnitude smaller in adult body mass. We demonstrate that the remarkable body size disparity of this clade is a consequence of different selective demands imposed by three major habitat use patterns-arboreality, terrestriality, and rock-dwelling. We reconstructed phylogenetic relationships and ancestral habitat use and applied model selection to determine that the best-fitting evolutionary models for species' adult size are those that infer oppositely directed adaptive evolution associated with terrestriality and rock-dwelling, with terrestrial lineages evolving extremely large size and rock-dwellers becoming very small. We also show that habitat use affects the evolution of several ecologically important morphological traits independently of body size divergence. These results suggest that habitat use exerts a strong, multidimensional influence on the evolution of morphological size and shape disparity in monitor lizards. © 2011 The Author(s).

The building-up of social relationships: behavioural types, social networks and cooperative breeding in a cichlid

PubMed Central

Schürch, Roger; Rothenberger, Susan; Heg, Dik

2010-01-01

Consistent individual differences in behavioural types may not only cause variation in life-history decisions, but may also affect the choice of social partners and sociality in general. Here, we tested whether and how behavioural type influences the establishment of social ties using the cooperatively breeding cichlid, Neolamprologus pulcher. In a habitat saturation experiment with individuals pre-tested for behavioural type, we first analysed whether behavioural type affected the likelihood of settlement (i.e. social status), group sizes, and the types of dominant and subordinate individuals accepted as group members. Corrected for effects of body size and sex, the behavioural type did not affect settlement. However, bold dominant males only accepted smaller females, and grouped with bold subordinates, while shy dominant males accepted larger females than themselves, and grouped with shy subordinates. Second, we analysed the relationships between behavioural type and the aggressiveness or affiliation social network. Behavioural type significantly affected the number and quality of connections within the two networks. We show that behavioural types affect group composition, social networks and status achieved, in interaction with body size. Thus, the interactions within groups may depend not only on age, size and sex, but also on the behavioural type of the individuals involved. PMID:21078660

Size-dependent selective mechanisms on males and females and the evolution of sexual size dimorphism in frogs.

PubMed

Nali, Renato C; Zamudio, Kelly R; Haddad, Célio F B; Prado, Cynthia P A

2014-12-01

Sexual size dimorphism (SSD) varies in animals from male biased to female biased. The evolution of SSD is potentially influenced by a number of factors, such as territoriality, fecundity, and temporal breeding patterns (explosive vs. prolonged). In general, frogs show female-biased SSD with broad variance among species. Using comparative methods, we examine how different selective forces affect male and female sizes, and we test hypotheses about size-dependent mechanisms shaping SSD in frogs. Male size was weakly associated with SSD in all size classes, and we found no significant association among SSD, male size, temporal breeding pattern, and male territoriality. In contrast, female size best explained SSD variation across all size classes but especially for small-bodied species. We found a stronger evolutionary association between female body size and fecundity, and this fecundity advantage was highest in explosively breeding species. Our data indicate that the fecundity advantage associated with female body size may not be linear, such that intermediate and large females benefit less with body size increases. Therefore, size-dependent selection in females associated with fecundity and breeding patterns is an important mechanism driving SSD evolution in frogs. Our study underscores the fact that lineage-specific ecology and behavior should be incorporated in comparative analyses of animal SSD.

Increased pheromone signaling by small male sea lamprey has distinct effects on female mate search and courtship

USGS Publications Warehouse

Buchinger, Tyler J.; Bussy, Ugo; Buchinger, Ethan G.; Fissette, Skye D.; Li, Weiming; Johnson, Nicholas

2017-01-01

Male body size affects access to mates in many animals. Attributes of sexual signals often correlate with body size due to physiological constraints on signal production. Larger males generally produce larger signals, but costs of being large or compensation by small males can result in smaller males producing signals of equal or greater magnitude. Female choice following multiple male traits with different relationships to size might further complicate the effect of male body size on access to mates. We report the relationship between male body size and pheromone signaling, and the effects on female mate search and courtship in the sea lamprey (Petromyzon marinus). We predicted that pheromone production in the liver and the liver mass to body mass ratio would remain constant across sizes, resulting in similar mass-adjusted pheromone release rates across sizes but a positive relationship between absolute pheromone release and body mass. Our results confirmed positive relationships between body mass and liver mass, and liver mass and the magnitude of the pheromone signal. Surprisingly, decreasing body mass was correlated with higher pheromone concentrations in the liver, liver mass to body mass ratios, and mass-adjusted pheromone release rates. In a natural stream, females more often entered nests treated with small versus large male odors. However, close-proximity courtship behaviors were similar in nests treated with small or large male odors. We conclude that small males exhibit increased release of the main pheromone component, but female discrimination of male pheromones follows several axes of variation with different relationships to size.

Detecting submerged bodies: controlled research using side-scan sonar to detect submerged proxy cadavers.

PubMed

Healy, Carrie A; Schultz, John J; Parker, Kenneth; Lowers, Bim

2015-05-01

Forensic investigators routinely deploy side-scan sonar for submerged body searches. This study adds to the limited body of literature by undertaking a controlled project to understand how variables affect detection of submerged bodies using side-scan sonar. Research consisted of two phases using small and medium-sized pig (Sus scrofa) carcasses as proxies for human bodies to investigate the effects of terrain, body size, frequency, swath width, and state of decomposition. Results demonstrated that a clear, flat, sandy pond floor terrain was optimal for detection of the target as irregular terrain and/or vegetation are major limitations that can obscure the target. A higher frequency towfish was preferred for small bodies, and a 20 m swath width allowed greater visibility and easier maneuverability of the boat in this environment. Also, the medium-sized carcasses were discernable throughout the 81-day study period, indicating that it is possible to detect bodies undergoing decomposition with side-scan sonar. © 2015 American Academy of Forensic Sciences.

Threat-level-dependent manipulation of signaled body size: dog growls' indexical cues depend on the different levels of potential danger.

PubMed

Bálint, Anna; Faragó, Tamás; Miklósi, Ádám; Pongrácz, Péter

2016-11-01

Body size is an important feature that affects fighting ability; however, size-related parameters of agonistic vocalizations are difficult to manipulate because of anatomical constraints within the vocal production system. Rare examples of acoustic size modulation are due to specific features that enable the sender to steadily communicate exaggerated body size. However, one could argue that it would be more adaptive if senders could adjust their signaling behavior to the fighting potential of their actual opponent. So far there has been no experimental evidence for this possibility. We tested this hypothesis by exposing family dogs (Canis familiaris) to humans with potentially different fighting ability. In a within-subject experiment, 64 dogs of various breeds consecutively faced two threateningly approaching humans, either two men or two women of different stature, or a man and a woman of similar or different stature. We found that the dogs' vocal responses were affected by the gender of the threatening stranger and the dog owner's gender. Dogs with a female owner, or those dogs which came from a household where both genders were present, reacted with growls of lower values of the Pitch-Formant component (including deeper fundamental frequency and lower formant dispersion) to threatening men. Our results are the first to show that non-human animals react with dynamic alteration of acoustic parameters related to their individual indexical features (body size), depending on the level of threat in an agonistic encounter.

Dynamic size responses to climate change: prevailing effects of rising temperature drive long-term body size increases in a semi-arid passerine.

PubMed

Gardner, Janet L; Amano, Tatsuya; Mackey, Brendan G; Sutherland, William J; Clayton, Mark; Peters, Anne

2014-07-01

Changes in animal body size have been widely reported as a correlate of contemporary climate change. Body size affects metabolism and fitness, so changing size has implications for resilience, yet the climatic factors that drive size variation remain poorly understood. We test the role of mean and extreme temperature, rainfall, and remotely sensed primary productivity (NDVI) as drivers of body size in a sedentary, semi-arid Australian passerine, Ptilotula (Lichenostomus)penicillatus, over 23 years. To distinguish effects due to differential growth from changes in population composition, we analysed first-year birds and adults separately and considered climatic variation at three temporal scales (current, previous, and preceding 5 years). The strongest effects related to temperature: in both age classes, larger size was associated with warmer mean temperatures in the previous year, contrary to Bergmann's Rule. Moreover, adults were larger in warmer breeding seasons, while first years was larger after heat waves; these effects are more likely to be mediated through size-dependent mortality, highlighting the role of body size in determining vulnerability to extinction. In addition to temperature, larger adult size was associated with lower primary productivity, which may reflect a trade-off between vegetative growth and nectar production, on which adults rely. Finally, lower rainfall was associated with decreasing size in first year and adults, most likely related to decreased food availability. Overall,body size increased over 23 years, strongly in first-year birds (2.7%) compared with adults (1%), with size outcomes a balance between competing drivers. As rainfall declined over time and productivity remained fairly stable, the temporal increase in body size appears largely driven by rising mean temperature and temperature extremes. Body size responses to environmental change are thus complex and dynamic, driven by effects on growth as well as mortality.

Body size mediates social and environmental effects on nest building behaviour in a fish with paternal care.

PubMed

Lehtonen, Topi K; Lindström, Kai; Wong, Bob B M

2015-07-01

Body size, social setting, and the physical environment can all influence reproductive behaviours, but their interactions are not well understood. Here, we investigated how male body size, male-male competition, and water turbidity influence nest-building behaviour in the sand goby (Pomatoschistus minutus), a marine fish with exclusive paternal care. We found that environmental and social factors affected the nest characteristics of small and large males differently. In particular, association between male size and the level of nest elaboration (i.e. the amount of sand piled on top of the nest) was positive only under clear water conditions. Similarly, male size and nest entrance size were positively associated only in the absence of competition. Such interactions may, in turn, help to explain the persistence of variation in reproductive behaviours, which-due to their importance in offspring survival-are otherwise expected to be under strong balancing selection.

Seeing the body distorts tactile size perception.

PubMed

Longo, Matthew R; Sadibolova, Renata

2013-03-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception. Copyright © 2012 Elsevier B.V. All rights reserved.

Incubation temperature influences trade-off between structural size and energy reserves in mallard hatchlings.

PubMed

Koláčková, Martina; Prokůpková, Ludmila; Albrecht, Tomáš; Hořák, David

2015-01-01

The reproductive success of precocial birds depends on investments in clutch formation and incubation. Egg quality strongly affects the phenotypic traits correlated with survival of the hatchling, but parental ability to maintain incubation temperature can also influence hatchling outcomes. The effect of incubation temperature on hatchling phenotype has been widely studied in reptiles but not in birds. The aim of this study was to explore the effects of egg mass and incubation temperature on the incubation period, hatchability, and hatchling phenotype of the mallard (Anas platyrhynchos). Mallard eggs were incubated under six constant incubation temperatures (ranging from 35.0° to 39.0°C). Hatchlings were weighed, and their structural size was measured. Some hatchlings were used for an examination of residual yolk sac mass and basic chemical composition of the yolk-free body. All investigated phenotypic traits except for chemical composition were positively correlated with egg mass. Incubation temperature did not affect hatchling body mass, but increased temperatures led to a decreased yolk-free body mass and structural size of hatchlings and to increased yolk sac mass. Our results suggest that there is a trade-off between the yolk-free body size and energetic reserves in the form of the yolk sac and that this trade-off is modulated by incubation temperature.

Size Effect of the 2-D Bodies on the Geothermal Gradient and Q-A Plot

NASA Astrophysics Data System (ADS)

Thakur, M.; Blackwell, D. D.

2009-12-01

Using numerical models we have investigated some of the criticisms on the Q-A plot of related to the effect of size of the body on the slope and reduced heat flow. The effects of horizontal conduction depend on the relative difference of radioactivity between the body and the country rock (assuming constant thermal conductivity). Horizontal heat transfer due to different 2-D bodies was numerically studied in order to quantify resulting temperature differences at the Moho and errors on the predication of Qr (reduced heat flow). Using the two end member distributions of radioactivity, the step model (thickness 10km) and exponential model, different 2-D models of horizontal scale (width) ranging from 10 -500 km were investigated. Increasing the horizontal size of the body tends to move observations closer towards the 1-D solution. A temperature difference of 50 oC is produced (for the step model) at Moho between models of width 10 km versus 500 km. In other words the 1-D solution effectively provides large scale averaging in terms of heat flow and temperature field in the lithosphere. For bodies’ ≤ 100 km wide the geotherms at shallower levels are affected, but at depth they converge and are 50 oC lower than that of the infinite plate model temperature. In case of 2-D bodies surface heat flow is decreased due to horizontal transfer of heat, which will shift the Q-A point vertically downward on the Q-A plot. The smaller the size of the body, the more will be the deviation from the 1-D solution and the more will be the movement of Q-A point downwards on a Q-A plot. On the Q-A plot, a limited points of bodies of different sizes with different radioactivity contrast (for the step and exponential model), exactly reproduce the reduced heat flow Qr. Thus the size of the body can affect the slope on a Q-A plot but Qr is not changed. Therefore, Qr ~ 32 mWm-2 obtained from the global terrain average Q-A plot represents the best estimate of stable continental mantle heat flow.

Relationship between Device Size and Body Weight in Dogs with Patent Ductus Arteriosus Undergoing Amplatz Canine Duct Occluder Deployment.

PubMed

Wesselowski, S; Saunders, A B; Gordon, S G

2017-09-01

Deployment of the Amplatz Canine Duct Occluder (ACDO) is the preferred method for minimally invasive occlusion of patent ductus arteriosus (PDA) in dogs, with appropriate device sizing crucial to successful closure. Dogs of any body weight can be affected by PDA. To describe the range of ACDO sizes deployed in dogs of various body weights for improved procedural planning and inventory selection and to investigate for correlation between minimal ductal diameter (MDD) and body weight. A total of 152 dogs undergoing ACDO deployment between 2008 and 2016. Body weight, age, breed, sex, and MDD obtained by angiography (MDD-A), MDD obtained by transesophageal echocardiography (MDD-TEE), and ACDO size deployed were retrospectively evaluated. Correlation between body weight and ACDO size, MDD-A and MDD-TEE was poor, with R-squared values of 0.4, 0.36, and 0.3, respectively. Femoral artery diameter in the smallest population of dogs placed inherent limitations on the use of larger device sizes, with no limitations on the wide range of device sizes required as patient size increased. The most commonly used ACDO devices were size 3 through 6, representing 57% of the devices deployed within the entire study population. Patent ductus arteriosus anatomy varies on an individual basis, with poor correlation between MDD and body weight. Weight-based assumptions about expected ACDO device size for a given patient are not recommended. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Experimentally induced anhydrobiosis in the tardigrade Richtersius coronifer: phenotypic factors affecting survival.

PubMed

Jönsson, K Ingemar; Rebecchi, Lorena

2002-11-01

The ability of some animal taxa (e.g., nematodes, rotifers, and tardigrades) to enter an ametabolic (cryptobiotic) state is well known. Nevertheless, the phenotypic factors affecting successful anhydrobiosis have rarely been investigated. We report a laboratory study on the effects of body size, reproductive condition, and energetic condition on anhydrobiotic survival in a population of the eutardigrade Richtersius coronifer. Body size and energetic condition interacted in affecting the probability of survival, while reproductive condition had no effect. Large tardigrades had a lower probability of survival than medium-sized tardigrades and showed a positive response in survival to energetic condition. This suggests that energy constrained the possibility for large tardigrades to enter and to leave anhydrobiosis. As a possible alternative explanation for low survival in the largest specimens we discuss the expression of senescence. In line with the view that processes related to anhydrobiosis are connected with energetic costs we documented a decrease in the size of storage cells over a period of anhydrobiosis, showing for the first time that energy is consumed in the process of anhydrobiosis in tardigrades. Copyright 2002 Wiley-Liss, Inc.

Effects of incubation temperature on growth and performance of the veiled chameleon (Chamaeleo calyptratus).

PubMed

Andrews, Robin M

2008-10-01

I evaluated the effect of incubation temperature on phenotypes of the veiled chameleon, Chamaeleo calyptratus. I chose this species for study because its large clutch size (30-40 eggs or more) allows replication within clutches both within and among experimental treatments. The major research objectives were (1) to assess the effect of constant low, moderate, and high temperatures on embryonic development, (2) to determine whether the best incubation temperature for embryonic development also produced the "best" hatchlings, and (3) to determine how a change in incubation temperature during mid-development would affect phenotype. To meet these objectives, I established five experimental temperature regimes and determined egg survival and incubation length and measured body size and shape, selected body temperatures, and locomotory performance of lizards at regular intervals from hatching to 90 d, or just before sexual maturity. Incubation temperature affected the length of incubation, egg survival, and body mass, but did not affect sprint speed or selected body temperature although selected body temperature affected growth in mass independently of treatment and clutch. Incubation at moderate temperatures provided the best conditions for both embryonic and post-hatching development. The highest incubation temperatures were disruptive to development; eggs had high mortality, developmental rate was low, and hatchlings grew slowly. Changes in temperature during incubation increased the among-clutch variance in incubation length relative to that of constant temperature treatments. Copyright 2008 Wiley-Liss, Inc.

Fitness consequences of artificial selection on relative male genital size

PubMed Central

Booksmythe, Isobel; Head, Megan L.; Keogh, J. Scott; Jennions, Michael D.

2016-01-01

Male genitalia often show remarkable differences among related species in size, shape and complexity. Across poeciliid fishes, the elongated fin (gonopodium) that males use to inseminate females ranges from 18 to 53% of body length. Relative genital size therefore varies greatly among species. In contrast, there is often tight within-species allometric scaling, which suggests strong selection against genital–body size combinations that deviate from a species' natural line of allometry. We tested this constraint by artificially selecting on the allometric intercept, creating lines of males with relatively longer or shorter gonopodia than occur naturally for a given body size in mosquitofish, Gambusia holbrooki. We show that relative genital length is heritable and diverged 7.6–8.9% between our up-selected and down-selected lines, with correlated changes in body shape. However, deviation from the natural line of allometry does not affect male success in assays of attractiveness, swimming performance and, crucially, reproductive success (paternity). PMID:27188478

Where do all the maternal effects go? Variation in offspring body size through ontogeny in the live-bearing fish Poecilia parae.

PubMed

Lindholm, Anna K; Hunt, John; Brooks, Robert

2006-12-22

Maternal effects are an important source of adaptive variation, but little is known about how they vary throughout ontogeny. We estimate the contribution of maternal effects, sire genetic and environmental variation to offspring body size from birth until 1 year of age in the live-bearing fish Poecilia parae. In both the sexes, maternal effects on body size were initially high in juveniles, and then declined to zero at sexual maturity. In sons, this was accompanied by a sharp rise in sire genetic variance, consistent with the expression of Y-linked loci affecting male size. In daughters, all variance components decreased with time, consistent with compensatory growth. There were significant negative among-dam correlations between early body size and the timing of sexual maturity in both sons and daughters. However, there was no relationship between early life maternal effects and adult longevity, suggesting that maternal effects, although important early in life, may not always influence late life-history traits.

Are long-term widespread avian body size changes related to food availability? A test using contemporaneous changes in carotenoid-based color.

PubMed

Little, Roellen; Gardner, Janet L; Amano, Tatsuya; Delhey, Kaspar; Peters, Anne

2017-05-01

Recent changes in global climate have been linked with changes in animal body size. While declines in body size are commonly explained as an adaptive thermoregulatory response to climate warming, many species do not decline in size, and alternative explanations for size change exist. One possibility is that temporal changes in animal body size are driven by changes in environmental productivity and food availability. This hypothesis is difficult to test due to the lack of suitable estimates that go back in time. Here, we use an alternative, indirect, approach and assess whether continent-wide changes over the previous 100 years in body size in 15 species of Australian birds are associated with changes in their yellow carotenoid-based plumage coloration. This type of coloration is strongly affected by food availability because birds cannot synthesize carotenoids and need to ingest them, and because color expression depends on general body condition. We found significant continent-wide intraspecific temporal changes in body size (wing length) and yellow carotenoid-based color (plumage reflectance) for half the species. Direction and magnitude of changes were highly variable among species. Meta-analysis indicated that neither body size nor yellow plumage color showed a consistent temporal trend and that changes in color were not correlated with changes in size over the past 100 years. We conclude that our data provide no evidence that broad-scale variation in food availability is a general explanation for continent-wide changes in body size in this group of species. The interspecific variability in temporal changes in size as well as color suggests that it might be unlikely that a single factor drives these changes, and more detailed studies of museum specimens and long-term field studies are required to disentangle the processes involved.

The Effect of Different Oceanic Abiotic Factors on Prokaryotic Body Sizes

NASA Astrophysics Data System (ADS)

Pidathala, S.; Bellon, M.; Heim, N.; Payne, J.

2016-12-01

We are studying the impact of abiotic factors in the Pacific and Atlantic on prokaryotic body sizes and genome sizes because we are interested in the manner in which abiotic factors influence genome sizes independent of their influence on body sizes. Some research has been done in the past on marine bacterial evolution, including data collection on marine ecology in relation to bacterial body sizes (Straza 2009). We are using the abiotic factors: temperature, salinity, and pH to compare the biovolumes/genome sizes of different phyla by using R. We made 9 scatter plots to model these relationships. Regardless of the phyla or the ocean, we found that there is no relation between pH, temperature, and body size, with several exceptions: Deinococcus. thermus has an indirect relationship with size in respect to temperature; size only correlates to temperature for phyla that are thermophiles. We also found that bacteria like D. thermus and Thermotogae are taxa only found in higher temperatures. Additionally, almost all phyla have genome sizes restricted by certain pH levels:, Proteobacteria only reach genomes with acidity levels greater than 6. In terms of salinity levels, certain bacteria are only found within a small range, and others, like Proteobacteria, can only reach genomes at low salinity levels. Finally, Proteobacteria have large genome sizes between 30 and 40 °, and Crenarchaeota have constant genome sizes in higher temperatures. Conclusively, we discovered that these abiotic factors generally do not affect body size, with the exception of D. thermus' indirect relationship to temperature due to its small biovolume in high temperatures. However, we determined that these abiotic factors have a great impact on genome sizes. This is due to genome size independence from body size. Also, genome size could have served as an adaptive feature for bacteria in marine environments, explaining why different phyla may have diverged to accommodate their lifestyles.

Body size variation of mammals in a fragmented, temperate rainforest.

PubMed

Lomolino, Mark V; Perault, David R

2007-08-01

Body size is perhaps the most important trait of an organism, affecting all of its physiological and ecological processes and, therefore, fundamentally influencing its ability to survive and reproduce in different environments, including those that have been modified by human activities. We tested the hypothesis that anthropogenic transformation of old-growth forest landscapes can result in significant intraspecific changes in body size of resident biotas. We collected data on five species of nonvolant mammals (common deer mouse[Peromyscus maniculatus], northwestern deer mouse[P. keeni], southern red-backed vole[Clethrionomys gapperi], montane shrew[Sorex monticolus], and Trowbridge's shrew[S. trowbridgii]) to test whether body size (mass and length) of these species varied across types of land cover (macrohabitats) and along elevational gradients of the fragmented, temperate rainforest of Olympic National Forest (Washington, U.S.A.). We measured 2168 and 1134 individuals for body mass and body length, respectively. Three species (P. keeni, S. monticolus, and S. trowbridgii) exhibited significantly different body size among macrohabitats: individuals from fragments were smaller than those in old-growth corridors and those in more extensive stands of old-growth forest. Body size of P. keeni was significantly correlated with elevation along corridors, peaking near the medial reaches of the corridors. The effects of anthropogenic transformations of this landscape of old-growth, temperate rainforest, although not universal among the five species, were significant and rapid-developing in just a few decades following tree harvests. Thus, anthropogenic fragmentation may influence not only the diversity, species composition, and densities of local biotas, but also one of the most fundamental and defining characteristics of native species-their body size.

Effects of body height, notebook computer size, and workstation height on recommended adjustments for proper work posture when operating a notebook computer.

PubMed

Nanthavanij, Suebsak; Jalil, Sakib; Ammarapala, Veeris

2008-12-01

Factors which are likely to affect recommended workstation and notebook computer (NBC) adjustments to obtain ergonomic work posture during NBC operation are investigated. They are: (1) body height, (2) NBC size, and (3) workstation height (i.e., seat and work surface heights). Six recommended adjustments which are evaluated include: (1) footrest height, (2) seat support height, (3) NBC base support height, (4) distance between the user's body and NBC (or user-NBC distance), (5) tilt angle of NBC base, and (6) screen angle. It is found that body height has a significant effect on footrest height and user-NBC distance while NBC size has a significant effect on user-NBC distance, tilt angle of NBC base, and screen angle. Workstation height, on the other hand, does not show any effect on the six recommended adjustments. However, the results suggest that there are interactions between body height and NBC size, and between body height and workstation height when evaluating their effects on footrest height, tilt angle of NBC base, and screen angle.

Canalization of body size matters for lifetime reproductive success of male predatory mites (Acari: Phytoseiidae)

PubMed Central

Walzer, Andreas; Schausberger, Peter

2014-01-01

The adaptive canalization hypothesis predicts that highly fitness-relevant traits are canalized via past selection, resulting in low phenotypic plasticity and high robustness to environmental stress. Accordingly, we hypothesized that the level of phenotypic plasticity of male body size of the predatory mites Phytoseiulus persimilis (low plasticity) and Neoseiulus californicus (high plasticity) reflects the effects of body size variation on fitness, especially male lifetime reproductive success (LRS). We first generated small and standard-sized males of P. persimilis and N. californicus by rearing them to adulthood under limited and ample prey supply, respectively. Then, adult small and standard-sized males were provided with surplus virgin females throughout life to assess their mating and reproductive traits. Small male body size did not affect male longevity or the number of fertilized females but reduced male LRS of P. persimilis but not N. californicus. Proximately, the lower LRS of small than standard-sized P. persimilis males correlated with shorter mating durations, probably decreasing the amount of transferred sperm. Ultimately, we suggest that male body size is more strongly canalized in P. persimilis than N. californicus because deviation from standard body size has larger detrimental fitness effects in P. persimilis than N. californicus. © 2014 The Authors. Biological Journal of the Linnean Society published by John Wiley & Sons Ltd on behalf of The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 889–899. PMID:25132689

Daily consumption of orange-fleshed sweet potato with added fat tends to increase total body vitamin A pool size in vitamin A depleted Bangladeshi women

USDA-ARS?s Scientific Manuscript database

We assessed the affect of daily consumption of orange-fleshed sweet potato (OFSP), with or without added fat, on the total body vitamin A (VA) pool size of Bangladeshi women with low initial VA status. Women (n=120) received for 60d either 1) 0 µg RAE/d as boiled white-fleshed sweet potatoes (WFSP) ...

Contest experience and body size affect different types of contest decisions.

PubMed

Chen, Yu-Ju; Hsu, Yuying

2016-11-01

This study examined the relative importance of contest experience and size differences to behavioral decisions over the course of contests. Using a mangrove rivulus fish, Kryptolebias marmoratus, we showed that although contest experience and size differences jointly determined contest outcomes, they affected contestants' interactions at different stages of contests. Contest experience affected behavioral decisions at earlier stages of contests, including the tendency and latency to launch attacks, the tendency to escalate contests into mutual attacks and the outcome of non-escalated contests. Once contests were escalated into mutual attacks, the degree of size difference affected the fish's persistence in escalation and chance of winning, but contest experience did not. These results support the hypothesis that contest experience modifies individuals' estimation of their fighting ability rather than their actual strength. Furthermore, (1) in contests between two naïve contestants, more than 60 % of fish that were 2-3 mm smaller than their opponent escalated the contest to physical fights, even though their larger opponents eventually won 92 % of escalated fights and (2) fish with a losing experience were very likely to retreat in the face of an opponent 2-3 mm smaller than them without escalating. The result that a 2-3 mm size advantage could not offset the influence of a losing experience on the tendency to escalate suggests that, as well as depending on body size, the fish's physical strength is influenced by other factors which require further investigation.

Professional hazards? The impact of models' body size on advertising effectiveness and women's body-focused anxiety in professions that do and do not emphasize the cultural ideal of thinness.

PubMed

Dittmar, Helga; Howard, Sarah

2004-12-01

Previous experimental research indicates that the use of average-size women models in advertising prevents the well-documented negative effect of thin models on women's body image, while such adverts are perceived as equally effective (Halliwell & Dittmar, 2004). The current study extends this work by: (a) seeking to replicate the finding of no difference in advertising effectiveness between average-size and thin models (b) examining level of ideal-body internalization as an individual, internal factor that moderates women's vulnerability to thin media models, in the context of (c) comparing women in professions that differ radically in their focus on, and promotion of, the sociocultural ideal of thinness for women--employees in fashion advertising (n = 75) and teachers in secondary schools (n = 75). Adverts showing thin, average-size and no models were perceived as equally effective. High internalizers in both groups of women felt worse about their body image after exposure to thin models compared to other images. Profession affected responses to average-size models. Teachers reported significantly less body-focused anxiety after seeing average-size models compared to no models, while there was no difference for fashion advertisers. This suggests that women in professional environments with less focus on appearance-related ideals can experience increased body-esteem when exposed to average-size models, whereas women in appearance-focused professions report no such relief.

Species-specific responses to landscape fragmentation: implications for management strategies

PubMed Central

Blanchet, Simon; Rey, Olivier; Etienne, Roselyne; Lek, Sovan; Loot, Géraldine

2010-01-01

Habitat fragmentation affects the integrity of many species, but little is known about species-specific sensitivity to fragmentation. Here, we compared the genetic structure of four freshwater fish species differing in their body size (Leuciscus cephalus; Leuciscus leuciscus; Gobio gobio and Phoxinus phoxinus) between a fragmented and a continuous landscape. We tested if, overall, fragmentation affected the genetic structure of these fish species, and if these species differed in their sensitivity to fragmentation. Fragmentation negatively affected the genetic structure of these species. Indeed, irrespective of the species identity, allelic richness and heterozygosity were lower, and population divergence was higher in the fragmented than in the continuous landscape. This response to fragmentation was highly species-specific, with the smallest fish species (P. phoxinus) being slightly affected by fragmentation. On the contrary, fish species of intermediate body size (L. leuciscus and G. gobio) were highly affected, whereas the largest fish species (L. cephalus) was intermediately affected by fragmentation. We discuss the relative role of dispersal ability and effective population size on the responses to fragmentation we report here. The weirs studied here are of considerable historical importance. We therefore conclude that restoration programmes will need to consider both this societal context and the biological characteristics of the species sharing this ecosystem. PMID:25567925

Oocyte size, egg index, and body lipid content in relation to body size in the solitary bee Megachile rotundata.

PubMed

O'Neill, Kevin M; Delphia, Casey M; O'Neill, Ruth P

2014-01-01

Females of solitary, nest-provisioning bees have relatively low fecundity, but produce large eggs as part of their overall strategy of investing substantially in each offspring. In intraspecific comparisons of several species of solitary, nest-provisioning bees and wasps, the size of the mature eggs produced increases with female body size. We further examined oocyte size-body size correlations in the solitary bee Megachile rotundata (F.), an important crop pollinator. We hypothesized that larger females carry larger basal oocytes (i.e., those next in line to be oviposited) but that body size-oocyte size correlations would be absent soon after emergence, before their first eggs fully matured. Because egg production is likely affected by the quantity of stored lipids carried over from the bees' immature stages, we also tested the hypothesis that female body size is correlated with the body lipid content at adult emergence, the time during which oocyte growth accelerates. We found significant correlations of body size with oocyte size variables chosen to reflect: (1) the magnitude of the investment in the next egg to be laid (i.e., the length and volume of the basal oocyte) and (2) the longer term potential to produce mature oocytes (i.e., the summed lengths and volumes of the three largest oocytes in each female). Positive correlations existed throughout the nesting season, even during the first week following adult emergence. The ability to produce and carry larger oocytes may be linked to larger females starting the nesting season with greater lipid stores (which we document here) or to greater space within the abdomen of larger females. Compared to other species of solitary bees, M. rotundata appears to have (1) smaller oocytes than solitary nest-provisioning bees in general, (2) comparable oocyte sizes relative to congeners, and (3) larger oocytes than related brood parasitic megachilids.

Body size and hosts of Triatoma infestans populations affect the size of bloodmeal contents and female fecundity in rural northwestern Argentina

PubMed Central

Fernández, María del Pilar; Cecere, María Carla; Cohen, Joel E.

2017-01-01

Human sleeping quarters (domiciles) and chicken coops are key source habitats of Triatoma infestans—the principal vector of the infection that causes Chagas disease—in rural communities in northern Argentina. Here we investigated the links among individual bug bloodmeal contents (BMC, mg), female fecundity, body length (L, mm), host blood sources and habitats. We tested whether L, habitat and host blood conferred relative fitness advantages using generalized linear mixed-effects models and a multimodel inference approach with model averaging. The data analyzed include 769 late-stage triatomines collected in 120 sites from six habitats in 87 houses in Figueroa, Santiago del Estero, during austral spring. L correlated positively with other body-size surrogates and was modified by habitat type, bug stage and recent feeding. Bugs from chicken coops were significantly larger than pig-corral and kitchen bugs. The best-fitting model of log BMC included habitat, a recent feeding, bug stage, log Lc (mean-centered log L) and all two-way interactions including log Lc. Human- and chicken-fed bugs had significantly larger BMC than bugs fed on other hosts whereas goat-fed bugs ranked last, in consistency with average blood-feeding rates. Fecundity was maximal in chicken-fed bugs from chicken coops, submaximal in human- and pig-fed bugs, and minimal in goat-fed bugs. This study is the first to reveal the allometric effects of body-size surrogates on BMC and female fecundity in a large set of triatomine populations occupying multiple habitats, and discloses the links between body size, microsite temperatures and various fitness components that affect the risks of transmission of Trypanosoma cruzi. PMID:29211791

Body size and hosts of Triatoma infestans populations affect the size of bloodmeal contents and female fecundity in rural northwestern Argentina.

PubMed

Gürtler, Ricardo E; Fernández, María Del Pilar; Cecere, María Carla; Cohen, Joel E

2017-12-01

Human sleeping quarters (domiciles) and chicken coops are key source habitats of Triatoma infestans-the principal vector of the infection that causes Chagas disease-in rural communities in northern Argentina. Here we investigated the links among individual bug bloodmeal contents (BMC, mg), female fecundity, body length (L, mm), host blood sources and habitats. We tested whether L, habitat and host blood conferred relative fitness advantages using generalized linear mixed-effects models and a multimodel inference approach with model averaging. The data analyzed include 769 late-stage triatomines collected in 120 sites from six habitats in 87 houses in Figueroa, Santiago del Estero, during austral spring. L correlated positively with other body-size surrogates and was modified by habitat type, bug stage and recent feeding. Bugs from chicken coops were significantly larger than pig-corral and kitchen bugs. The best-fitting model of log BMC included habitat, a recent feeding, bug stage, log Lc (mean-centered log L) and all two-way interactions including log Lc. Human- and chicken-fed bugs had significantly larger BMC than bugs fed on other hosts whereas goat-fed bugs ranked last, in consistency with average blood-feeding rates. Fecundity was maximal in chicken-fed bugs from chicken coops, submaximal in human- and pig-fed bugs, and minimal in goat-fed bugs. This study is the first to reveal the allometric effects of body-size surrogates on BMC and female fecundity in a large set of triatomine populations occupying multiple habitats, and discloses the links between body size, microsite temperatures and various fitness components that affect the risks of transmission of Trypanosoma cruzi.

The thermal environment of the nest affects body and cell size in the solitary red mason bee (Osmia bicornis L.).

PubMed

Kierat, Justyna; Szentgyörgyi, Hajnalka; Czarnoleski, Marcin; Woyciechowski, Michał

2017-08-01

Many ectotherms grow larger at lower temperatures than at higher temperatures. This pattern, known as the temperature-size rule, is often accompanied by plastic changes in cell size, which can mechanistically explain the thermal dependence of body size. However, the theory predicts that thermal plasticity in cell size has adaptive value for ectotherms because there are different optimal cell-membrane-to-cell-volume ratios at different temperatures. At high temperatures, the demand for oxygen is high; therefore, a large membrane surface of small cells is beneficial because it allows high rates of oxygen transport into the cell. The metabolic costs of maintaining membranes become more important at low temperatures than at high temperatures, which favours large cells. In a field experiment, we manipulated the thermal conditions inside nests of the red mason bee, a solitary bee that does not regulate the temperature in its nests and whose larvae develop under ambient conditions. We assessed the effect of temperature on body mass and ommatidia size (our proxy of cell size). The body and cell sizes decreased in response to a higher mean temperature and greater temperature fluctuations. This finding is in accordance with predictions of the temperature-size rule and optimal cell size theory and suggests that both the mean temperature and the magnitude of temperature fluctuations are important for determining body and cell sizes. Additionally, we observed that males of the red mason bee tend to have larger ommatidia in relation to their body mass than females, which might play an important role during mating flight. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differences in motor performance between children and adolescents in Mozambique and Portugal: impact of allometric scaling.

PubMed

Dos Santos, Fernanda Karina; Nevill, Allan; Gomes, Thayse Natacha Q F; Chaves, Raquel; Daca, Timóteo; Madeira, Aspacia; Katzmarzyk, Peter T; Prista, António; Maia, José A R

2016-05-01

Children from developed and developing countries have different anthropometric characteristics which may affect their motor performance (MP). To use the allometric approach to model the relationship between body size and MP in youth from two countries differing in socio-economic status-Portugal and Mozambique. A total of 2946 subjects, 1280 Mozambicans (688 girls) and 1666 Portuguese (826 girls), aged 10-15 years were sampled. Height and weight were measured and the reciprocal ponderal index (RPI) was computed. MP included handgrip strength, 1-mile run/walk, curl-ups and standing long jump tests. A multiplicative allometric model was adopted to adjust for body size differences across countries. Differences in MP between Mozambican and Portuguese children exist, invariably favouring the latter. The allometric models used to adjust MP for differences in body size identified the optimal body shape to be either the RPI or even more linear, i.e. approximately (height/mass(0.25)). Having adjusted the MP variables for differences in body size, the differences between Mozambican and Portuguese children were invariably reduced and, in the case of grip strength, reversed. These results reinforce the notion that significant differences exist in MP across countries, even after adjusting for differences in body size.

Media effects of experimental presentation of the ideal physique on eating disorder symptoms: a meta-analysis of laboratory studies.

PubMed

Hausenblas, Heather A; Campbell, Anna; Menzel, Jessie E; Doughty, Jessica; Levine, Michael; Thompson, J Kevin

2013-02-01

Older meta-analyses of the effects of the media's portrayal of the ideal physique have found small effects revealing that exposure to the ideal physique increases body image concerns. These meta-analyses also included correlational, quasi-experimental, and experimental studies, with limited examination of moderators and other relevant outcomes besides body image. We conducted a systematic literature search and identified 33 experimental (i.e., pre and post data for both experimental and control groups) laboratory studies examining the effects of acute exposure to the media's portrayal of the ideal physique on eating disorder symptoms (i.e., body image, positive affect, negative affect, self-esteem, anger, anxiety and depression) and the mechanisms that moderate this effect. Fourteen separate meta-analyses revealed a range of small to moderate effect sizes for change in outcomes from pre to post for both experimental and control groups. Exposure to images of the ideal physique resulted in small effect sizes for increased depression and anger and decreased self-esteem and positive affect. Moderator analyses revealed moderate effect sizes for increased depression and body dissatisfaction among high-risk participants. This meta-analysis makes it clear that media exposure of the ideal physique results in small changes in eating disorder symptoms, particularly with participants at high risk for developing an eating disorder. Further research is needed to examine the longitudinal effects of media exposure of eating disorder symptoms. Copyright © 2012 Elsevier Ltd. All rights reserved.

Lead effects on body composition and organ size of wintering canvasbacks Aythya valisineria in Louisiana

USGS Publications Warehouse

Pace, R.M.; Hohman, W.L.; Custer, T.W.

1999-01-01

We tested whether lead exposure, as evidenced by liver lead concentration, affected body composition and organ sizes of canvasback ducks Aythya valisineria in Louisiana during winter 1987-88. After adjusting for body size, sex, age, and site and month of collection, we found decreases in ingesta-free body mass; breast, leg, and body protein; body fat; intestine length; and liver and gizzard masses associated with increased liver lead concentrations. There were no apparent associations between liver lead concentrations and testes and body ash masses, or caecal length. We used the concentration of 26.7 ppm of liver lead on a dry matter (dm) basis as indicative of lead toxicosis. We predicted that a canvasback with 26.7 ppm dm liver lead would weigh 209 g less and have 105 g less fat than an unexposed individual. Whereas many lead exposed canvasbacks may survive through winter, their subsequent survival, ability to reproduce and perform other annual cycle events may be compromised. We recommend management to make lead unavailable to waterfowl at major concentration areas and periodic monitoring of lead contamination in waterfowl populations.

Considering an Affect Regulation Framework for Examining the Association Between Body Dissatisfaction and Positive Body Image in Black Older Adolescent Females: Does Body Mass Index Matter?

PubMed Central

Butler-Ajibade, Phoebe; Robinson, Seronda A.

2014-01-01

The present study provided an initial evaluation of an affect regulation model describing the association between body dissatisfaction and two contemporary measures of positive body image among 247 Black college-bound older adolescent females. We further tested whether possessing a higher body mass index (BMI) would strengthen these associations. Self-reported height and weight were used to calculate BMI. Respondents also completed a culturally-sensitive figure rating scale along with assessments of body appreciation and body image flexibility. Results indicated a robust positive association between the two measures of positive body image; BMI was the strongest predictor of both body appreciation and body image flexibility with body size discrepancy (current minus ideal) contributing incremental variance to both models tested. Implications for improving our understanding of the association between positive and negative body image and bolstering positive body image to promote health-protective behaviors among Black young women at this developmental juncture are discussed. PMID:25079011

The extended Price equation quantifies species selection on mammalian body size across the Palaeocene/Eocene Thermal Maximum.

PubMed

Rankin, Brian D; Fox, Jeremy W; Barrón-Ortiz, Christian R; Chew, Amy E; Holroyd, Patricia A; Ludtke, Joshua A; Yang, Xingkai; Theodor, Jessica M

2015-08-07

Species selection, covariation of species' traits with their net diversification rates, is an important component of macroevolution. Most studies have relied on indirect evidence for its operation and have not quantified its strength relative to other macroevolutionary forces. We use an extension of the Price equation to quantify the mechanisms of body size macroevolution in mammals from the latest Palaeocene and earliest Eocene of the Bighorn and Clarks Fork Basins of Wyoming. Dwarfing of mammalian taxa across the Palaeocene/Eocene Thermal Maximum (PETM), an intense, brief warming event that occurred at approximately 56 Ma, has been suggested to reflect anagenetic change and the immigration of small bodied-mammals, but might also be attributable to species selection. Using previously reconstructed ancestor-descendant relationships, we partitioned change in mean mammalian body size into three distinct mechanisms: species selection operating on resident mammals, anagenetic change within resident mammalian lineages and change due to immigrants. The remarkable decrease in mean body size across the warming event occurred through anagenetic change and immigration. Species selection also was strong across the PETM but, intriguingly, favoured larger-bodied species, implying some unknown mechanism(s) by which warming events affect macroevolution. © 2015 The Author(s).

Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content.

PubMed

Garzke, Jessica; Hansen, Thomas; Ismar, Stefanie M H; Sommer, Ulrich

2016-01-01

Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts.

Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content

PubMed Central

Hansen, Thomas; Ismar, Stefanie M. H.; Sommer, Ulrich

2016-01-01

Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1–5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts. PMID:27224476

Deforestation and stream warming affect body size of Amazonian fishes.

PubMed

Ilha, Paulo; Schiesari, Luis; Yanagawa, Fernando I; Jankowski, KathiJo; Navas, Carlos A

2018-01-01

Declining body size has been suggested to be a universal response of organisms to rising temperatures, manifesting at all levels of organization and in a broad range of taxa. However, no study to date evaluated whether deforestation-driven warming could trigger a similar response. We studied changes in fish body size, from individuals to assemblages, in streams in Southeastern Amazonia. We first conducted sampling surveys to validate the assumption that deforestation promoted stream warming, and to test the hypothesis that warmer deforested streams had reduced fish body sizes relative to cooler forest streams. As predicted, deforested streams were up to 6 °C warmer and had fish 36% smaller than forest streams on average. This body size reduction could be largely explained by the responses of the four most common species, which were 43-55% smaller in deforested streams. We then conducted a laboratory experiment to test the hypothesis that stream warming as measured in the field was sufficient to cause a growth reduction in the dominant fish species in the region. Fish reared at forest stream temperatures gained mass, whereas those reared at deforested stream temperatures lost mass. Our results suggest that deforestation-driven stream warming is likely to be a relevant factor promoting observed body size reductions, although other changes in stream conditions, like reductions in organic matter inputs, can also be important. A broad scale reduction in fish body size due to warming may be occurring in streams throughout the Amazonian Arc of Deforestation, with potential implications for the conservation of Amazonian fish biodiversity and food supply for people around the Basin.

Deforestation and stream warming affect body size of Amazonian fishes

PubMed Central

Yanagawa, Fernando I.; Jankowski, KathiJo; Navas, Carlos A.

2018-01-01

Declining body size has been suggested to be a universal response of organisms to rising temperatures, manifesting at all levels of organization and in a broad range of taxa. However, no study to date evaluated whether deforestation-driven warming could trigger a similar response. We studied changes in fish body size, from individuals to assemblages, in streams in Southeastern Amazonia. We first conducted sampling surveys to validate the assumption that deforestation promoted stream warming, and to test the hypothesis that warmer deforested streams had reduced fish body sizes relative to cooler forest streams. As predicted, deforested streams were up to 6 °C warmer and had fish 36% smaller than forest streams on average. This body size reduction could be largely explained by the responses of the four most common species, which were 43–55% smaller in deforested streams. We then conducted a laboratory experiment to test the hypothesis that stream warming as measured in the field was sufficient to cause a growth reduction in the dominant fish species in the region. Fish reared at forest stream temperatures gained mass, whereas those reared at deforested stream temperatures lost mass. Our results suggest that deforestation-driven stream warming is likely to be a relevant factor promoting observed body size reductions, although other changes in stream conditions, like reductions in organic matter inputs, can also be important. A broad scale reduction in fish body size due to warming may be occurring in streams throughout the Amazonian Arc of Deforestation, with potential implications for the conservation of Amazonian fish biodiversity and food supply for people around the Basin. PMID:29718960

Nesting environment may drive variation in eggshell structure and egg characteristics in the Testudinata.

PubMed

Deeming, D Charles

2018-05-14

Testudines exhibit considerable variation in the degree of eggshell calcification, which affects eggshell conductance, water physiology of the embryos, and calcium metabolism of embryos. However, the underlying reason for different shell types has not been explored. Phylogenetically controlled analyses examined relationships between egg size, shell mass, and clutch size in ∼200 turtle species from a range of body sizes and assigned by family as laying either rigid- or pliable-shelled eggs. Shell type affected egg breadth relative to pelvic dimensions, egg mass, and relative shell mass but did not affect size, mass, or total shell mass of the clutch. These results suggest that calcium availability may be a function of body size and the type of shell may reflect in part the interplay between clutch size and egg size. It was further concluded that the eggshell probably evolved as a means of physical protection. Differences in shell calcification may not primarily reflect reproductive parameters but rather correlate with the acidity of a species' nesting environment. Low pH environments may have thicker calcareous layer to counteract the erosion caused by the soil and maintain the integrity of the physical barrier. Limited calcium availability may constrain clutch size. More neutral nesting substrates expose eggshells to less erosion so calcification per egg can be reduced and this allows larger clutch sizes. This pattern is also reflected in thick, calcified crocodilian eggs. Further research is needed to test whether eggshell calcification in the testudines correlates with nest pH in order to verify this relationship. © 2018 Wiley Periodicals, Inc.

Costs of immune responses are related to host body size and lifespan

DOE PAGES

Brace, Amber J.; Lajeunesse, Marc J.; Ardia, Daniel R.; ...

2017-06-01

A central assumption in ecological immunology is that immune responses are costly, with costs manifesting directly (e.g., increases in metabolic rate and increased amino acid usage) or as tradeoffs with other life processes (e.g., reduced growth and reproductive success). Across taxa, host longevity, timing of maturity, and reproductive effort affect the organization of immune systems. It is reasonable, therefore, to expect that these and related factors should also affect immune activation costs. Specifically, species that spread their breeding efforts over a long lifetime should experience lower immune costs than those that mature and breed quickly and die comparatively early. Likewise,more » body mass should affect immune costs, as body size affects the extent to which hosts are exposed to parasites as well as how hosts can combat infections (via its effects on metabolic rates and other factors). Here in this paper, we used phylogenetic meta-regression to reveal that, in general, animals incur costs of immune activation, but small species that are relatively long-lived incur the largest costs. These patterns probably arise because of the relative need for defense when infection risk is comparatively high and fitness can only be realized over a comparatively long period. However, given the diversity of species considered here and the overall modest effects of body mass and life history on immune costs, much more research is necessary before generalizations are appropriate.« less

Costs of immune responses are related to host body size and lifespan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brace, Amber J.; Lajeunesse, Marc J.; Ardia, Daniel R.

A central assumption in ecological immunology is that immune responses are costly, with costs manifesting directly (e.g., increases in metabolic rate and increased amino acid usage) or as tradeoffs with other life processes (e.g., reduced growth and reproductive success). Across taxa, host longevity, timing of maturity, and reproductive effort affect the organization of immune systems. It is reasonable, therefore, to expect that these and related factors should also affect immune activation costs. Specifically, species that spread their breeding efforts over a long lifetime should experience lower immune costs than those that mature and breed quickly and die comparatively early. Likewise,more » body mass should affect immune costs, as body size affects the extent to which hosts are exposed to parasites as well as how hosts can combat infections (via its effects on metabolic rates and other factors). Here in this paper, we used phylogenetic meta-regression to reveal that, in general, animals incur costs of immune activation, but small species that are relatively long-lived incur the largest costs. These patterns probably arise because of the relative need for defense when infection risk is comparatively high and fitness can only be realized over a comparatively long period. However, given the diversity of species considered here and the overall modest effects of body mass and life history on immune costs, much more research is necessary before generalizations are appropriate.« less

Intraspecific variation in body size does not alter the effects of mesopredators on prey.

PubMed

Gallagher, Austin J; Brandl, Simon J; Stier, Adrian C

2016-12-01

As humans continue to alter the species composition and size structure of marine food webs, it is critical to understand size-dependent effects of predators on prey. Yet, how shifts in predator body size mediate the effect of predators is understudied in tropical marine ecosystems, where anthropogenic harvest has indirectly increased the density and size of small-bodied predators. Here, we combine field surveys and a laboratory feeding experiment in coral reef fish communities to show that small and large predators of the same species can have similar effects. Specifically, surveys show that the presence of a small predator ( Paracirrhites arcatus ) was correlated with lower chances of prey fish presence, but these correlations were independent of predator size. Experimental trials corroborated the size-independent effect of the predator; attack rates were indistinguishable between small and large predators, suggesting relatively even effects of hawkfish in various size classes on the same type of prey. Our results indicate that the effects of small predators on coral reefs can be size-independent, suggesting that variation in predator size-structure alone may not always affect the functional role of these predators.

Fitness variation in response to artificial selection for reduced cell area, cell number and wing area in natural populations of Drosophila melanogaster.

PubMed

Trotta, Vincenzo; Calboli, Federico C F; Ziosi, Marcello; Cavicchi, Sandro

2007-08-16

Genetically based body size differences are naturally occurring in populations of Drosophila melanogaster, with bigger flies in the cold. Despite the cosmopolitan nature of body size clines in more than one Drosophila species, the actual selective mechanisms controlling the genetic basis of body size variation are not fully understood. In particular, it is not clear what the selective value of cell size and cell area variation exactly is. In the present work we determined variation in viability, developmental time and larval competitive ability in response to crowding at two temperatures after artificial selection for reduced cell area, cell number and wing area in four different natural populations of D. melanogaster. No correlated effect of selection on viability or developmental time was observed among all selected populations. An increase in competitive ability in one thermal environment (18 degrees C) under high larval crowding was observed as a correlated response to artificial selection for cell size. Viability and developmental time are not affected by selection for the cellular component of body size, suggesting that these traits only depend on the contingent genetic makeup of a population. The higher larval competitive ability shown by populations selected for reduced cell area seems to confirm the hypothesis that cell area mediated changes have a relationship with fitness, and might be the preferential way to change body size under specific circumstances.

Climate alters intraspecific variation in copepod effect traits through pond food webs.

PubMed

Charette, Cristina; Derry, Alison M

2016-05-01

Essential fatty acids (EFAs) are primarily generated by phytoplankton in aquatic ecosystems, and can limit the growth, development, and reproduction of higher consumers. Among the most critical of the EFAs are highly unsaturated fatty acids (HUFAs), which are only produced by certain groups of phytoplankton. Changing environmental conditions can alter phytoplankton community and fatty acid composition and affect the HUFA content of higher trophic levels. Almost no research has addressed intraspecific variation in HUFAs in zooplankton, nor intraspecific relationships of HUFAs with body size and fecundity. This is despite that intraspecific variation in HUFAs can exceed interspecific variation and that intraspecific trait variation in body size and fecundity is increasingly recognized to have an important role in food web ecology (effect traits). Our study addressed the relative influences of abiotic selection and food web effects associated with climate change on intraspecific differences and interrelationships between HUFA content, body size, and fecundity of freshwater copepods. We applied structural equation modeling and regression analyses to intraspecific variation in a dominant calanoid copepod, Leptodiatomus minutus, among a series of shallow north-temperate ponds. Climate-driven diurnal temperature fluctuations favored the coexistence of diversity of phytoplankton groups with different temperature optima and nutritive quality. This resulted in unexpected positive relationships between temperature, copepod DHA content and body size. Temperature correlated positively with diatom biovolume, and mediated relationships between copepod HUFA content and body size, and between copepod body size and fecundity. The presence of brook trout further accentuated these positive effects in warm ponds, likely through nutrient cycling and stimulation of phytoplankton resources. Climate change may have previously unrecognized positive effects on freshwater copepod DHA content, body size, and fecundity in the small, shallow bodies of inland waters that are commonly found in north-temperate landscapes.

Geographic body size variation in the periodical cicadas Magicicada: implications for life cycle divergence and local adaptation.

PubMed

Koyama, T; Ito, H; Kakishima, S; Yoshimura, J; Cooley, J R; Simon, C; Sota, T

2015-06-01

Seven species in three species groups (Decim, Cassini and Decula) of periodical cicadas (Magicicada) occupy a wide latitudinal range in the eastern United States. To clarify how adult body size, a key trait affecting fitness, varies geographically with climate conditions and life cycle, we analysed the relationships of population mean head width to geographic variables (latitude, longitude, altitude), habitat annual mean temperature (AMT), life cycle and species differences. Within species, body size was larger in females than males and decreased with increasing latitude (and decreasing habitat AMT), following the converse Bergmann's rule. For the pair of recently diverged 13- and 17-year species in each group, 13-year cicadas were equal in size or slightly smaller on average than their 17-year counterparts despite their shorter developmental time. This fact suggests that, under the same climatic conditions, 17-year cicadas have lowered growth rates compared to their 13-years counterparts, allowing 13-year cicadas with faster growth rates to achieve body sizes equivalent to those of their 17-year counterparts at the same locations. However, in the Decim group, which includes two 13-year species, the more southerly, anciently diverged 13-year species (Magicicada tredecim) was characterized by a larger body size than the other, more northerly 13- and 17-year species, suggesting that local adaptation in warmer habitats may ultimately lead to evolution of larger body sizes. Our results demonstrate how geographic clines in body size may be maintained in sister species possessing different life cycles. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Juvenile exposure to predator cues induces a larger egg size in fish

PubMed Central

Segers, Francisca H. I. D.; Taborsky, Barbara

2012-01-01

When females anticipate a hazardous environment for their offspring, they can increase offspring survival by producing larger young. Early environmental experience determines egg size in different animal taxa. We predicted that a higher perceived predation risk by juveniles would cause an increase in the sizes of eggs that they produce as adults. To test this, we exposed juveniles of the mouthbrooding cichlid Eretmodus cyanostictus in a split-brood experiment either to cues of a natural predator or to a control situation. After maturation, females that had been confronted with predators produced heavier eggs, whereas clutch size itself was not affected by the treatment. This effect cannot be explained by a differential female body size because the predator treatment did not influence growth trajectories. The observed increase of egg mass is likely to be adaptive, as heavier eggs gave rise to larger young and in fish, juvenile predation risk drops sharply with increasing body size. This study provides the first evidence that predator cues perceived by females early in life positively affect egg mass, suggesting that these cues allow her to predict the predation risk for her offspring. PMID:21976689

Size, sounds and sex: interactions between body size and harmonic convergence signals determine mating success in Aedes aegypti.

PubMed

Cator, Lauren J; Zanti, Zacharo

2016-12-01

Several new mosquito control strategies will involve the release of laboratory reared males which will be required to compete with wild males for mates. Currently, the determinants of male mating success remain unclear. The presence of convergence between male and female harmonic flight tone frequencies during a mating attempt have been found to increase male mating success in the yellow fever mosquito, Aedes aegypti. Size has also been implicated as a factor in male mating success. Here, we investigated the relationships among body size, harmonic convergence signalling, and mating success. We predicted that harmonic convergence would be an important determinant of mating success and that large individuals would be more likely to converge. We used diet to manipulate male and female body size and then measured acoustic interactions during mating attempts between pairs of different body sizes. Additionally, we used playback experiments to measure the direct effect of size on signalling performance. In live pair interactions, harmonic convergence was found to be a significant predictor of copula formation. However, we also found interactions between harmonic convergence behaviour and body size. The probability that a given male successfully formed a copula was a consequence of his size, the size of the female encountered, and whether or not they converged. While convergence appears to be predictive of mating success regardless of size, the positive effect of convergence was modulated by size combinations. In playbacks, adult body size did not affect the probability of harmonic convergence responses. Both body size and harmonic convergence signalling were found to be determinants of male mating success. Our results suggest that in addition to measuring convergence ability of mass release lines that the size distribution of released males may need to be adjusted to complement the size distribution of females. We also found that diet amount alone cannot be used to increase male mating success or convergence probability. A clearer understanding of convergence behaviours, their relationship to mating success, and factors influencing convergence ability would provide the groundwork for improving the mating performance of laboratory reared lines.

Oxygen no longer plays a major role in Body Size Evolution

NASA Astrophysics Data System (ADS)

Datta, H.; Sachson, W.; Heim, N. A.; Payne, J.

2015-12-01

When observing the long-term relationship between atmospheric oxygen and the maximum size in organisms across the Geozoic (~3.8 Ga - present), it appears that as oxygen increases, organism size grows. However, during the Phanerozoic (541 Ma - Present) oxygen levels varied, so we set out to test the hypothesis that oxygen levels drive patterns marine animal body size evolution. Expected decreases in maximum size due to a lack of oxygen do not occur, and instead, body size continues to increase regardless. In the oxygen data, a relatively low atmospheric oxygen percentage can support increasing body size, so our research tries to determine whether lifestyle affects body size in marine organisms. The genera in the data set were organized based on their tiering, motility, and feeding, such as a pelagic, fully-motile, predator. When organisms fill a certain ecological niche to take advantage of resources, they will have certain life modes, rather than randomly selected traits. For example, even in terrestrial environments, large animals have to constantly feed themselves to support their expensive terrestrial lifestyle which involves fairly consistent movement, and the structural support necessary for that movement. Only organisms with access to high energy food sources or large amounts of food can support themselves, and that is before they expend energy elsewhere. Organisms that expend energy frugally when active or have slower metabolisms in comparison to body size have a more efficient lifestyle and are generally able to grow larger, while those who have higher energy demands like predators are limited to comparatively smaller sizes. Therefore, in respect to the fossil record and modern measurements of animals, the metabolism and lifestyle of an organism dictate its body size in general. With this further clarification on the patterns of evolution, it will be easier to observe and understand the reasons for the ecological traits of organisms today.

Body size as a latent variable in a structural equation model: thermal acclimation and energetics of the leaf-eared mouse.

PubMed

Nespolo, Roberto F; Arim, Matías; Bozinovic, Francisco

2003-07-01

Body size is one of the most important determinants of energy metabolism in mammals. However, the usual physiological variables measured to characterize energy metabolism and heat dissipation in endotherms are strongly affected by thermal acclimation, and are also correlated among themselves. In addition to choosing the appropriate measurement of body size, these problems create additional complications when analyzing the relationships among physiological variables such as basal metabolism, non-shivering thermogenesis, thermoregulatory maximum metabolic rate and minimum thermal conductance, body size dependence, and the effect of thermal acclimation on them. We measured these variables in Phyllotis darwini, a murid rodent from central Chile, under conditions of warm and cold acclimation. In addition to standard statistical analyses to determine the effect of thermal acclimation on each variable and the body-mass-controlled correlation among them, we performed a Structural Equation Modeling analysis to evaluate the effects of three different measurements of body size (body mass, m(b); body length, L(b) and foot length, L(f)) on energy metabolism and thermal conductance. We found that thermal acclimation changed the correlation among physiological variables. Only cold-acclimated animals supported our a priori path models, and m(b) appeared to be the best descriptor of body size (compared with L(b) and L(f)) when dealing with energy metabolism and thermal conductance. However, while m(b) appeared to be the strongest determinant of energy metabolism, there was an important and significant contribution of L(b) (but not L(f)) to thermal conductance. This study demonstrates how additional information can be drawn from physiological ecology and general organismal studies by applying Structural Equation Modeling when multiple variables are measured in the same individuals.

Implications of scaled δ15N fractionation for community predator-prey body mass ratio estimates in size-structured food webs.

PubMed

Reum, Jonathan C P; Jennings, Simon; Hunsicker, Mary E

2015-11-01

Nitrogen stable isotope ratios (δ(15) N) may be used to estimate community-level relationships between trophic level (TL) and body size in size-structured food webs and hence the mean predator to prey body mass ratio (PPMR). In turn, PPMR is used to estimate mean food chain length, trophic transfer efficiency and rates of change in abundance with body mass (usually reported as slopes of size spectra) and to calibrate and validate food web models. When estimating TL, researchers had assumed that fractionation of δ(15) N (Δδ(15) N) did not change with TL. However, a recent meta-analysis indicated that this assumption was not as well supported by data as the assumption that Δδ(15) N scales negatively with the δ(15) N of prey. We collated existing fish community δ(15) N-body size data for the Northeast Atlantic and tropical Western Arabian Sea with new data from the Northeast Pacific. These data were used to estimate TL-body mass relationships and PPMR under constant and scaled Δδ(15) N assumptions, and to assess how the scaled Δδ(15) N assumption affects our understanding of the structure of these food webs. Adoption of the scaled Δδ(15) N approach markedly reduces the previously reported differences in TL at body mass among fish communities from different regions. With scaled Δδ(15) N, TL-body mass relationships became more positive and PPMR fell. Results implied that realized prey size in these size-structured fish communities are less variable than previously assumed and food chains potentially longer. The adoption of generic PPMR estimates for calibration and validation of size-based fish community models is better supported than hitherto assumed, but predicted slopes of community size spectra are more sensitive to a given change or error in realized PPMR when PPMR is small. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Constraints of body size and swimming velocity on the ability of juvenile rainbow trout to endure periods without food

USGS Publications Warehouse

Simpkins, D.G.; Hubert, W.A.; Martinez Del Rio, C.; Rule, D.C.

2004-01-01

The hypothesis that body size and swimming velocity affect proximate body composition, wet mass and size-selective mortality of fasted fish was evaluated using small (107 mm mean total length, LT) and medium (168 mm mean LT) juvenile rainbow trout Oncorhynchus mykiss that were sedentary or swimming (c. 1 or 2 body lengths-1) and fasted for 147 days. The initial amount of energy reserves in the bodies of fish varied with L T. Initially having less lipid mass and relatively higher mass-specific metabolic rates caused small rainbow trout that were sedentary to die of starvation sooner and more frequently than medium-length fish that were sedentary. Swimming at 2 body length s-1 slightly increased the rate of lipid catabolism relative to 1 body length s-1, but did not increase the occurrence of mortality among medium fish. Death from starvation occurred when fish had <3.2% lipid remaining in their bodies. Juvenile rainbow trout endured long periods without food, but their ability to resist death from starvation was limited by their length and initial lipid reserves. ?? 2004 The Fisheries Society of the British Isles.

Mating Success, Longevity, and Fertility of Diabrotica virgifera virgifera LeConte (Chrysomelidae: Coleoptera) in Relation to Body Size and Cry3Bb1-Resistant and Cry3Bb1-Susceptible Genotypes

PubMed Central

French, Bryan Wade; Hammack, Leslie; Tallamy, Douglas W.

2015-01-01

Insect resistance to population control methodologies is a widespread problem. The development of effective resistance management programs is often dependent on detailed knowledge regarding the biology of individual species and changes in that biology associated with resistance evolution. This study examined the reproductive behavior and biology of western corn rootworm beetles of known body size from lines resistant and susceptible to the Cry3Bb1 protein toxin expressed in transgenic Bacillus thuringiensis maize. In crosses between, and within, the resistant and susceptible genotypes, no differences occurred in mating frequency, copulation duration, courtship duration, or fertility; however, females mated with resistant males showed reduced longevity. Body size did not vary with genotype. Larger males and females were not more likely to mate than smaller males and females, but larger females laid more eggs. Moderately strong, positive correlation occurred between the body sizes of successfully mated males and females; however, weak correlation also existed for pairs that did not mate. Our study provided only limited evidence for fitness costs associated with the Cry3Bb1-resistant genotype that might reduce the persistence in populations of the resistant genotype but provided additional evidence for size-based, assortative mating, which could favor the persistence of resistant genotypes affecting body size. PMID:26569315

Tactic changes in dusky frillgoby Bathygobius fuscus sneaker males: effects of body size and nest availability.

PubMed

Takegaki, T; Kaneko, T; Matsumoto, Y

2013-02-01

Field and laboratory studies were conducted to examine the effects of nest availability and body size on changes in male mating tactics from sneaking to nest-holding in the dusky frillgoby Bathygobius fuscus. In the field, the body size of nest-holding males decreased from early to mid-breeding season, suggesting the possibility of a change in the tactics of sneaker males to nest-holding. Many sneaker males did not use vacant spawning nests even when size-matched nests were available, but they continued to reproduce as sneakers. Similarly, in aquarium experiments with available vacant nests, some sneaker males became nest-holders irrespective of their body size, but some did not. These results showed that nest availability is not a limiting factor for changes in tactics by sneaker males in this species. Because tactic-unchanged sneaker males were co-housed with larger nest-holding males in the tanks, the body size of nearby nest-holding males may have affected the decision to change tactics for sneaker males. Moreover, smaller individuals among tactic-changed males tended to spend more time until spawning, probably because they had relatively larger costs and smaller benefits of reproduction as nest-holding males compared to larger males. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Macroscale patterns in body size of intertidal crustaceans provide insights on climate change effects.

PubMed

Jaramillo, Eduardo; Dugan, Jenifer E; Hubbard, David M; Contreras, Heraldo; Duarte, Cristian; Acuña, Emilio; Schoeman, David S

2017-01-01

Predicting responses of coastal ecosystems to altered sea surface temperatures (SST) associated with global climate change, requires knowledge of demographic responses of individual species. Body size is an excellent metric because it scales strongly with growth and fecundity for many ectotherms. These attributes can underpin demographic as well as community and ecosystem level processes, providing valuable insights for responses of vulnerable coastal ecosystems to changing climate. We investigated contemporary macroscale patterns in body size among widely distributed crustaceans that comprise the majority of intertidal abundance and biomass of sandy beach ecosystems of the eastern Pacific coasts of Chile and California, USA. We focused on ecologically important species representing different tidal zones, trophic guilds and developmental modes, including a high-shore macroalga-consuming talitrid amphipod (Orchestoidea tuberculata), two mid-shore scavenging cirolanid isopods (Excirolana braziliensis and E. hirsuticauda), and a low-shore suspension-feeding hippid crab (Emerita analoga) with an amphitropical distribution. Significant latitudinal patterns in body sizes were observed for all species in Chile (21° - 42°S), with similar but steeper patterns in Emerita analoga, in California (32°- 41°N). Sea surface temperature was a strong predictor of body size (-4% to -35% °C-1) in all species. Beach characteristics were subsidiary predictors of body size. Alterations in ocean temperatures of even a few degrees associated with global climate change are likely to affect body sizes of important intertidal ectotherms, with consequences for population demography, life history, community structure, trophic interactions, food-webs, and indirect effects such as ecosystem function. The consistency of results for body size and temperature across species with different life histories, feeding modes, ecological roles, and microhabitats inhabiting a single widespread coastal ecosystem, and for one species, across hemispheres in this space-for-time substitution, suggests predictions of ecosystem responses to thermal effects of climate change may potentially be generalised, with important implications for coastal conservation.

Macroscale patterns in body size of intertidal crustaceans provide insights on climate change effects

PubMed Central

Dugan, Jenifer E.; Hubbard, David M.; Contreras, Heraldo; Duarte, Cristian; Acuña, Emilio; Schoeman, David S.

2017-01-01

Predicting responses of coastal ecosystems to altered sea surface temperatures (SST) associated with global climate change, requires knowledge of demographic responses of individual species. Body size is an excellent metric because it scales strongly with growth and fecundity for many ectotherms. These attributes can underpin demographic as well as community and ecosystem level processes, providing valuable insights for responses of vulnerable coastal ecosystems to changing climate. We investigated contemporary macroscale patterns in body size among widely distributed crustaceans that comprise the majority of intertidal abundance and biomass of sandy beach ecosystems of the eastern Pacific coasts of Chile and California, USA. We focused on ecologically important species representing different tidal zones, trophic guilds and developmental modes, including a high-shore macroalga-consuming talitrid amphipod (Orchestoidea tuberculata), two mid-shore scavenging cirolanid isopods (Excirolana braziliensis and E. hirsuticauda), and a low-shore suspension-feeding hippid crab (Emerita analoga) with an amphitropical distribution. Significant latitudinal patterns in body sizes were observed for all species in Chile (21° - 42°S), with similar but steeper patterns in Emerita analoga, in California (32°- 41°N). Sea surface temperature was a strong predictor of body size (-4% to -35% °C-1) in all species. Beach characteristics were subsidiary predictors of body size. Alterations in ocean temperatures of even a few degrees associated with global climate change are likely to affect body sizes of important intertidal ectotherms, with consequences for population demography, life history, community structure, trophic interactions, food-webs, and indirect effects such as ecosystem function. The consistency of results for body size and temperature across species with different life histories, feeding modes, ecological roles, and microhabitats inhabiting a single widespread coastal ecosystem, and for one species, across hemispheres in this space-for-time substitution, suggests predictions of ecosystem responses to thermal effects of climate change may potentially be generalised, with important implications for coastal conservation. PMID:28481897

COMPARISON OF ORGAN DOSES IN HUMAN PHANTOMS: VARIATIONS DUE TO BODY SIZE AND POSTURE.

PubMed

Feng, Xu; Xiang-Hong, Jia; Qian, Liu; Xue-Jun, Yu; Zhan-Chun, Pan; Chun-Xin, Yang

2017-04-20

Organ dose calculations performed using human phantoms can provide estimates of astronauts' health risks due to cosmic radiation. However, the characteristics of such phantoms strongly affect the estimation precision. To investigate organ dose variations with body size and posture in human phantoms, a non-uniform rational B-spline boundary surfaces model was constructed based on cryosection images. This model was used to establish four phantoms with different body size and posture parameters, whose organs parameters were changed simultaneously and which were voxelised with 4 × 4 × 4 mm3 resolution. Then, using Monte Carlo transport code, the organ doses caused by ≤500 MeV isotropic incident protons were calculated. The dose variations due to body size differences within a certain range were negligible, and the doses received in crouching and standing-up postures were similar. Therefore, a standard Chinese phantom could be established, and posture changes cannot effectively protect astronauts during solar particle events. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Considering an affect regulation framework for examining the association between body dissatisfaction and positive body image in Black older adolescent females: does body mass index matter?

PubMed

Webb, Jennifer B; Butler-Ajibade, Phoebe; Robinson, Seronda A

2014-09-01

The present study provided an initial evaluation of an affect regulation model describing the association between body dissatisfaction and two contemporary measures of positive body image among 247 Black college-bound older adolescent females. We further tested whether possessing a higher body mass index (BMI) would strengthen these associations. Self-reported height and weight were used to calculate BMI. Respondents also completed a culturally-sensitive figure rating scale along with assessments of body appreciation and body image flexibility. Results indicated a robust positive association between the two measures of positive body image; BMI was the strongest predictor of both body appreciation and body image flexibility with body size discrepancy (current minus ideal) contributing incremental variance to both models tested. Implications for improving our understanding of the association between positive and negative body image and bolstering positive body image to promote health-protective behaviors among Black young women at this developmental juncture are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of body image on pregnancy weight gain.

PubMed

Mehta, Ushma J; Siega-Riz, Anna Maria; Herring, Amy H

2011-04-01

The majority of women gain more weight during pregnancy than what is recommended. Since gestational weight gain is related to short and long-term maternal health outcomes, it is important to identify women at greater risk of not adhering to guidelines. The objective of this study was to examine the relationship between body image and gestational weight gain. The Body Image Assessment for Obesity tool was used to measure ideal and current body sizes in 1,192 women participating in the Pregnancy, Infection and Nutrition Study. Descriptive and multivariable techniques were used to assess the effects of ideal body size and discrepancy score (current-ideal body sizes), which reflected the level of body dissatisfaction, on gestational weight gain. Women who preferred to be thinner had increased risk of excessive gain if they started the pregnancy at a BMI ≤26 kg/m(2) but a decreased risk if they were overweight or obese. Comparing those who preferred thin body silhouettes to those who preferred average size silhouettes, low income women had increased risk of inadequate weight gain [RR = 1.76 (1.08, 2.88)] while those with lower education were at risk of excessive gain [RR = 1.11 (1.00, 1.22)]. Our results revealed that body image was associated with gestational weight gain but the relationship is complex. Identifying factors that affect whether certain women are at greater risk of gaining outside of guidelines may improve our ability to decrease pregnancy-related health problems.

Influences of sex, ontogeny and body size on the thermal ecology of Liolaemus lutzae (Squamata, Liolaemidae) in a restinga remnant in Southeastern Brazil.

PubMed

Maia-Carneiro, Thiago; Rocha, Carlos Frederico Duarte

2013-01-01

Variations in body temperature (Tb) of lizards can be partially explained by intrinsic factors such as sex, ontogeny and body size. Liolaemus lutzae is a lizard species restricted to restingas in the Brazilian coast in the state of Rio de Janeiro. Herein, we studied sexual dimorphism and influences of sex, ontogeny, and body size to the Tb of L. lutzae. Adult males were larger than adult females, probably due to both intersexual selection and intra-sexual selection. There was intersexual difference in lizards' Tb (males hotter than females), but Tb did not differ after factored out for the effects of body size. The mean Tb of juvenile lizards was higher than that of adults after factored out for the effect of body mass. It is possible that adults may have excluded juveniles from microhabitats with better thermal regimes. Also, this might have occurred due to requirements of juveniles to maintain high growth rates. Forage searching for prey by juveniles also exposes them to high environmental temperatures. Juveniles also may have higher Tb than co-specific adults (relative to body mass) to favor prey capture. In absolute values, adult lizards tended to use microhabitats with lower temperatures than that used by juveniles, possibly to avoid risks of overheating and death. Body temperature and snout-vent length were positively related, as well as body temperature and body mass, presumably caused by the thermal inertia of the bodies (trend of a body to resist to changes in its temperature). Intrinsic factors such as sex, ontogeny and body size can affect the thermal ecology of L. lutzae, despite coastal habitat features to which they are exposed also influences the body temperature of active lizards in restinga habitats. Copyright © 2012 Elsevier Ltd. All rights reserved.

Competition and pesticide exposure affect development of invasive (Rhinella marina) and native (Fejervarya vittigera) rice paddy amphibian larvae.

PubMed

Shuman-Goodier, Molly E; Singleton, Grant R; Propper, Catherine R

2017-12-01

Increased pesticide use in rice agricultural ecosystems may alter competitive interactions between invasive and native amphibian species. We conducted an experiment with two rice paddy amphibians found in Luzon, Philippines, the invasive cane toad (Rhinella marina) and the endemic Luzon wart frog (Fejervarya vittigera), to determine whether exposure to a common herbicide, butachlor, drives competitive interactions in favor of the invasive amphibian. Our results revealed that competition had a strong effect on the development of both species, but in opposing directions; Luzon wart frog tadpoles were smaller and developed slower than when raised alone, whereas cane toad tadpoles were larger and developed faster. Contrary to our predictions, development and survival of endemic wart frog tadpoles was not affected by butachlor, whereas invasive cane toad tadpoles were affected across several endpoints including gene expression, body size, and survival. We also observed an interaction between pesticide exposure and competition for the cane toad, where survival declined but body size and expression of thyroid sensitive genes increased. Taken together, our findings indicate that the success of the cane toad larvae in rice fields may be best explained by increased rates of development and larger body sizes of tadpoles in response to competition with native Luzon wart frog tadpoles rather than lower sensitivity to a common pesticide. Our results for the cane toad also provide evidence that butachlor can disrupt thyroid hormone mediated development in amphibians, and further demonstrate that important species interactions such as competition can be affected by pesticide exposure in aquatic ecosystems.

Bariatric Surgery Misconceptions

MedlinePlus

... is more than the chance of dying from obesity. Truth: As your body size increases, longevity decreases. ... lose and maintain weight, individuals affected by severe obesity just need to go on a diet and ...

Selection on male size, leg length and condition during mate search in a sexually highly dimorphic orb-weaving spider.

PubMed

Foellmer, Matthias W; Fairbairn, Daphne J

2005-02-01

Mate search plays a central role in hypotheses for the adaptive significance of extreme female-biased sexual size dimorphism (SSD) in animals. Spiders (Araneae) are the only free-living terrestrial taxon where extreme SSD is common. The "gravity hypothesis" states that small body size in males is favoured during mate search in species where males have to climb to reach females, because body length is inversely proportional to achievable speed on vertical structures. However, locomotive performance of males may also depend on relative leg length. Here we examine selection on male body size and leg length during mate search in the highly dimorphic orb-weaving spider Argiope aurantia, using a multivariate approach to distinguish selection targeted at different components of size. Further, we investigate the scaling relationships between male size and energy reserves, and the differential loss of reserves. Adult males do not feed while roving, and a size-dependent differential energy storage capacity may thus affect male performance during mate search. Contrary to predictions, large body size was favoured in one of two populations, and this was due to selection for longer legs. Male size was not under selection in the second population, but we detected direct selection for longer third legs. Males lost energy reserves during mate search, but this was independent of male size and storage capacity scaled isometrically with size. Thus, mate search is unlikely to lead to selection for small male size, but the hypothesis that relatively longer legs in male spiders reflect a search-adapted morphology is supported.

Effects of the Booroola (FecB) genotypes on growth performance, ewe's productivity efficiency and litter size in Garole x Malpura sheep.

PubMed

Kumar, S; Mishra, A K; Kolte, A P; Arora, A L; Singh, D; Singh, V K

2008-05-01

The present study was conducted to evaluate the effects of FecB genotypes on body weight, average daily gain (ADG), ewe's productivity efficiency (EPE) and litter size in FecB introgressed GarolexMalpura (GM) crossbred sheep. A total of 235 GM lambs were selected randomly and screened for FecB mutation using forced RFLP-PCR. The majority (69.8%) of GM individuals were carriers (BB and B+) for the FecB mutation and frequency of the FecB allele was about 0.40. The FecB genotypes were significantly (P<0.01) associated with the lamb's body weights from birth to 12 months of age. The generation wise (F(1), F(2) and F(3)), lamb's body weight did not differ significantly at birth, 6 and 12 months of the age, while it differed significantly (P<0.05) at 3 and 9 months of age. The ADG1 (0-3 months) was significantly associated (P<0.05), but not the ADG2 (3-6 months) and ADG3 (6-12 months) between genotypes. Type of birth and sex significantly (P<0.01) affected the body weight from birth to 12 months of age; and body weight of single born lambs was significantly higher (P<0.01) than that of twins and triplets from birth to 12 months of age. Type of birth significantly (P<0.01) affected the ADG1, but had no significant effect on ADG2 and ADG3. Year of birth did not affect the birth and weaning weights, but it significantly affected (P<0.01) the body weight and ADG's after weaning ages. The EPE was affected significantly (P<0.01) by the FecB genotypes at birth, 3 and 12 months of age. The EPE of B+ and BB ewes were 7.86 kg (36.9%) and 2.32 kg (10.9%) higher as compared to ++ ewes at 12 months of age, respectively. The mean litter size of BB ewes (2.17+/-0.24) was significantly higher (P<0.01) than that of B+ ewes (1.73+/-0.04) and ++ ewes (1.03+/-0.23). The present study indicated that the body weight and ADG of carrier lambs (BB and B+) was comparatively lower than that of non-carriers (++), while EPE of B+ ewes was comparatively higher than that of BB and ++ ewes. Further, it is interesting to note that heterozygous and homozygous state of individuals increased 0.70 and 1.14 extra lambs as compared to non-carriers (++), respectively.

Giving Permission to Be Fat? Examining the Impact of Body-Based Belief Systems

ERIC Educational Resources Information Center

Robertson, Lorayne; Thomson, Dianne

2014-01-01

Body image might be explained as "how we picture ourselves" and, while the image may or may not be accurate, it can affect decisions about physical, social, and emotional health. Schools are seen as potential sites for universal intervention programs to promote health, self-esteem, and size acceptance, and also to discourage unhealthy…

Maternal active smoking and newborn body composition.

PubMed

Samper, M P; Jiménez-Muro, A; Nerín, I; Marqueta, A; Ventura, P; Rodríguez, G

2012-03-01

Maternal smoking during pregnancy is associated with a reduction in birth size but very few studies have collated changes in neonatal anthropometry. Our aims were both to assess body composition differences by anthropometry between new-borns from smoking mothers and those from non-smoking mothers, and to show whether these differences affect proportional body mass distribution. Caucasian mothers and their full term singleton new-borns (N=1216) were selected during 2009. A structured questionnaire was completed regarding obstetric and demographic data, as well as tobacco consumption. Women were categorized, according to their smoking habits, into a non-smoking group (never smoked or stopped smoking prior to pregnancy) and a smoking group (smoked throughout pregnancy). 22.1% of mothers smoked during pregnancy (median: 6 cigarettes/day, range: l-40). Smoking mothers were significantly younger than non-smoking mothers but there were no differences regarding other aspects which could affect infant weight. Infants from non-smoking mothers were heavier, longer, and body circumferences were all larger than those from smoking mothers (p<0.001), but the Ponderal Index showed no statistical differences. Skinfold thicknesses were significantly lower in new-borns from smoking mothers but these differences were less evident than those from body size. Subcutaneous fat distribution did not show statistical differences between the two groups. After gestational age, to smoke during gestation is the second main determinant of birth weight. Smoking during pregnancy involves a generalized reduction of most axiological parameters as a result of proportionate fetal growth impairment. In those infants born from mothers who smoked during gestation, neonatal lean body mass appears to be more affected than body fat, and distribution of subcutaneous fat is not different. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Objectification in Virtual Romantic Contexts: Perceived Discrepancies between Self and Partner Ideals Differentially affect Body Consciousness in Women and Men

PubMed Central

Overstreet, Nicole M.; Quinn, Diane M.; Marsh, Kerry L.

2015-01-01

The current study examined whether exposure to sexually objectifying images in a potential romantic partner's virtual apartment affects discrepancies between people's perception of their own appearance (i.e., self-perceptions) and their perception of the body ideal that is considered desirable to a romantic partner (i.e., partner-ideals). Participants were 114 heterosexual undergraduate students (57 women and 57 men) from a northeastern U.S. university. The study used a 2 (Participant Gender) x 2 (Virtual Environment: Sexualized vs. Non-Sexualized) between-subjects design. We predicted that women exposed to sexually objectifying images in a virtual environment would report greater discrepancies between their self-perceptions and partner-ideals than men, which in turn would contribute to women's body consciousness. Findings support this hypothesis and show that perceived discrepancies account for the relationship between exposure to sexually objectifying images and body consciousness for women but not men. We also found gender asymmetries in objectification responses when each component of perceived discrepancies, i.e., self-perceptions versus perceptions of a romantic partner's body ideal, were examined separately. For men, exposure to muscular sexualized images was significantly associated with their self-perceptions but not their perceptions of the body size that is considered desirable to a romantic partner. For women, exposure to thin sexualized images was significantly associated with their perceptions that a romantic partner preferred a woman with a smaller body size. However, exposure to these images did not affect women's self-perceptions. Implications for gender asymmetries in objectification responses and perceived discrepancies that include a romantic partner's perceptions are discussed. PMID:26594085

Effects of Hypergravity on Statocyst Development in Embryonic Aplysia californica

NASA Technical Reports Server (NTRS)

Pedrozo, Hugo A.; Wiederhold, Michael L.

1994-01-01

Aplysia californica is a marine gastropod mollusc with bilaterally paired statocysts as gravity-reccptor organs. Data from three experiments in which embryonic Aplysia californica were exposed to 2 x g arc discussed. The experimental groups were exposed to excess gravity until hatching (9-12 day), whereas control groups were maintained at normal gravity. Body diameter was measured before exposure to 2 x g. Statocyst, statolith and body diameter were each determined for samples of 20 embryos from each group on successive days. Exposure to excess gravity led to an increase in body size. Statocyst size was not affected by exposure to 2 x g. Statolith size decreased with treatment as indicated by smaller statolith-to-body ratios observed in the 2 x g group in all three experiments. Mean statolith diameter was significantly smaller for the 2 x g group in Experiment 1 but not in Experiments 2 and 3. Defective statocysts, characterized by very small or no statoliths, were found in the 2 x g group in Experiments 1 and 2.

Exercise, dietary obesity, and growth in the rat

NASA Technical Reports Server (NTRS)

Pitts, G. C.; Bull, L. S.

1977-01-01

Experiments were conducted on weanling male rats 35 days old and weighing about 100 g to determine how endurance-type exercise and high-fat diet administered during growth influence body mass and composition. The animals were divided into four weight-matched groups of 25 animals each: group I - high-fat diet, exercised; group II - chow, exercised; group III - high-fat diet, sedentary; and group IV - chow, sedentary. During growth, masses of water, muscle and skin increased as functions of body size; bone as a function of age; and heart, liver, gut, testes, and CNS were affected by combinations of size, age, activity, and diet. Major conclusions are that growth in body size is expressed more precisely with fat-free body mass (FFBM), that late rectilinear growth is probably attributable to fat accretion, and that the observed influences on FFBM of exercise and high-fat diet are obtained only if the regimen is started at or before age 5-7 weeks.

Efficacy of Four Nematicides Against the Reproduction and Development of Pinewood Nematode, Bursaphelenchus xylophilus

PubMed Central

Bi, Zhenzhen; Gong, Yanting; Huang, Xiaojuan; Yu, Hongshi; Bai, Liqun; Hu, Jiafu

2015-01-01

To understand the efficacy of emamectin benzoate, avermectin, milbemectin, and thiacloprid on the reproduction and development of Bursaphelenchus xylophilus, seven parameters, namely population growth, fecundity, egg hatchability, larval lethality, percent larval development, body size, and sexual ratio, were investigated using sublethal (LC20) doses of these compounds in the laboratory. Emamectin benzoate treatment led to a significant suppression in population size, brood size, and percent larval development with 411, 3.50, and 49.63%, respectively, compared to 20850, 24.33, and 61.43% for the negative control. The embryonic and larval lethality increased obviously from 12.47% and 13.70% to 51.37% and 75.30%, respectively. In addition, the body length was also significantly reduced for both males and females in the emamectin benzoate treatment. Avermectin and milbemectin were also effective in suppressing population growth by increasing larval lethality and reducing larval development, although they did not affect either brood size or embryonic lethality. Body length for both male and female worms was increased by avermectin. Thiacloprid caused no adverse reproductive effects, although it suppressed larval development. Sexual ratio was not affected by any of these four nematicides. Our results indicate that emamectin benzoate, milbemectin, and avermectin are effective against the reproduction of B. xylophilus. We think these three nematicides can be useful for the control of pine wilt disease. PMID:26170474

Efficacy of Four Nematicides Against the Reproduction and Development of Pinewood Nematode, Bursaphelenchus xylophilus.

PubMed

Bi, Zhenzhen; Gong, Yanting; Huang, Xiaojuan; Yu, Hongshi; Bai, Liqun; Hu, Jiafu

2015-06-01

To understand the efficacy of emamectin benzoate, avermectin, milbemectin, and thiacloprid on the reproduction and development of Bursaphelenchus xylophilus, seven parameters, namely population growth, fecundity, egg hatchability, larval lethality, percent larval development, body size, and sexual ratio, were investigated using sublethal (LC20) doses of these compounds in the laboratory. Emamectin benzoate treatment led to a significant suppression in population size, brood size, and percent larval development with 411, 3.50, and 49.63%, respectively, compared to 20850, 24.33, and 61.43% for the negative control. The embryonic and larval lethality increased obviously from 12.47% and 13.70% to 51.37% and 75.30%, respectively. In addition, the body length was also significantly reduced for both males and females in the emamectin benzoate treatment. Avermectin and milbemectin were also effective in suppressing population growth by increasing larval lethality and reducing larval development, although they did not affect either brood size or embryonic lethality. Body length for both male and female worms was increased by avermectin. Thiacloprid caused no adverse reproductive effects, although it suppressed larval development. Sexual ratio was not affected by any of these four nematicides. Our results indicate that emamectin benzoate, milbemectin, and avermectin are effective against the reproduction of B. xylophilus. We think these three nematicides can be useful for the control of pine wilt disease.

Temperatures in Excess of Critical Thresholds Threaten Nestling Growth and Survival in A Rapidly-Warming Arid Savanna: A Study of Common Fiscals

PubMed Central

Cunningham, Susan J.; Martin, Rowan O.; Hojem, Carryn L.

2013-01-01

Frequency, duration, and intensity of hot-weather events are all predicted to increase with climate warming. Despite this, mechanisms by which temperature increases affect individual fitness and drive population-level changes are poorly understood. We investigated the link between daily maximum air temperature (tmax) and breeding success of Kalahari common fiscals (Lanius collaris) in terms of the daily effect on nestling body-mass gain, and the cumulative effect on size and age of fledglings. High tmax reduced mass gain of younger, but not older nestlings and average nestling-period tmax did not affect fledgling size. Instead, the frequency with which tmax exceeded critical thresholds (tcrits) significantly reduced fledging body mass (tcrit = 33°C) and tarsus length (tcrit = 37°C), as well as delaying fledging (tcrit = 35°C). Nest failure risk was 4.2% per day therefore delays reduced fledging probability. Smaller size at fledging often correlates with reduced lifetime fitness and might also underlie documented adult body-size reductions in desert birds in relation to climate warming. Temperature thresholds above which organisms incur fitness costs are probably common, as physiological responses to temperature are non-linear. Understanding the shape of the relationship between temperature and fitness has implications for our ability to predict species’ responses to climate change. PMID:24040296

Body size, growth and life span: implications for the polewards range shift of Octopus tetricus in south-eastern Australia.

PubMed

Ramos, Jorge E; Pecl, Gretta T; Moltschaniwskyj, Natalie A; Strugnell, Jan M; León, Rafael I; Semmens, Jayson M

2014-01-01

Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters.

Body Size, Growth and Life Span: Implications for the Polewards Range Shift of Octopus tetricus in South-Eastern Australia

PubMed Central

Ramos, Jorge E.; Pecl, Gretta T.; Moltschaniwskyj, Natalie A.; Strugnell, Jan M.; León, Rafael I.; Semmens, Jayson M.

2014-01-01

Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters. PMID:25090250

Vocal tract length and acoustics of vocalization in the domestic dog (Canis familiaris).

PubMed

Riede, T; Fitch, T

1999-10-01

The physical nature of the vocal tract results in the production of formants during vocalisation. In some animals (including humans), receivers can derive information (such as body size) about sender characteristics on the basis of formant characteristics. Domestication and selective breeding have resulted in a high variability in head size and shape in the dog (Canis familiaris), suggesting that there might be large differences in the vocal tract length, which could cause formant behaviour to affect interbreed communication. Lateral radiographs were made of dogs from several breeds ranging in size from a Yorkshire terrier (2.5 kg) to a German shepherd (50 kg) and were used to measure vocal tract length. In addition, we recorded an acoustic signal (growling) from some dogs. Significant correlations were found between vocal tract length, body mass and formant dispersion, suggesting that formant dispersion can deliver information about the body size of the vocalizer. Because of the low correlation between vocal tract length and the first formant, we predict a non-uniform vocal tract shape.

Level of UV-B radiation influences the effects of glyphosate-based herbicide on the spotted salamander.

PubMed

Levis, Nicholas A; Johnson, Jarrett R

2015-07-01

Glyphosate-based herbicides are the number one pesticide in the United States and are used commonly around the world. Understanding the affects of glyphosate-based herbicides on non-target wildlife, for example amphibians, is critical for evaluation of regulations pertaining to the use of such herbicides. Additionally, it is important to understand how variation in biotic and abiotic environmental conditions, such as UV-B light regime, could potentially affect how glyphosate-based herbicides interact with non-target species. This study used artificial pond mesocosms to identify the effects of generic glyphosate-based herbicide (GLY-4 Plus) on mortality, cellular immune response, body size, and morphological plasticity of larvae of the spotted salamander (Ambystoma maculatum) under conditions that reflect moderate (UV(M)) and low (UV(L)) UV-B light regimes. Survival within a given UV-B level was unaffected by herbicide presence or absence. However, when herbicide was present, survival varied between UV-B levels with higher survival in UV(M) conditions. Herbicide presence in the UV(M) treatments also decreased body size and reduced cellular immune response. In the UV(L) treatments, the presence of herbicide increased body size and affected tail morphology. Finally, in the absence of herbicide, body size and cellular immune response were higher in UV(M) treatments compared to UV(L) treatments. Thus, the effects of herbicide on salamander fitness were dependent on UV-B level. As anthropogenic habitat modifications continue to alter landscapes that contain amphibian breeding ponds, salamanders may increasingly find themselves in locations with reduced canopy cover and increased levels of UV light. Our findings suggest that the probability of surviving exposure to the glyphosate-based herbicide used in this study may be elevated in more open canopy ponds, but the effects on other components of fitness may be varied and unexpected.

The effect of age and body composition on body mass estimation of males using the stature/bi-iliac method.

PubMed

Junno, Juho-Antti; Niskanen, Markku; Maijanen, Heli; Holt, Brigitte; Sladek, Vladimir; Niinimäki, Sirpa; Berner, Margit

2018-02-01

The stature/bi-iliac breadth method provides reasonably precise, skeletal frame size (SFS) based body mass (BM) estimations across adults as a whole. In this study, we examine the potential effects of age changes in anthropometric dimensions on the estimation accuracy of SFS-based body mass estimation. We use anthropometric data from the literature and our own skeletal data from two osteological collections to study effects of age on stature, bi-iliac breadth, body mass, and body composition, as they are major components behind body size and body size estimations. We focus on males, as relevant longitudinal data are based on male study samples. As a general rule, lean body mass (LBM) increases through adolescence and early adulthood until people are aged in their 30s or 40s, and starts to decline in the late 40s or early 50s. Fat mass (FM) tends to increase until the mid-50s and declines thereafter, but in more mobile traditional societies it may decline throughout adult life. Because BM is the sum of LBM and FM, it exhibits a curvilinear age-related pattern in all societies. Skeletal frame size is based on stature and bi-iliac breadth, and both of those dimensions are affected by age. Skeletal frame size based body mass estimation tends to increase throughout adult life in both skeletal and anthropometric samples because an age-related increase in bi-iliac breadth more than compensates for an age-related stature decline commencing in the 30s or 40s. Combined with the above-mentioned curvilinear BM change, this results in curvilinear estimation bias. However, for simulations involving low to moderate percent body fat, the stature/bi-iliac method works well in predicting body mass in younger and middle-aged adults. Such conditions are likely to have applied to most human paleontological and archaeological samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Convergent evolution of reduced energy demands in extremophile fish

PubMed Central

Arias-Rodriguez, Lenin; Tobler, Michael

2017-01-01

Convergent evolution in organismal function can arise from nonconvergent changes in traits that contribute to that function. Theory predicts that low resource availability and high maintenance costs in extreme environments select for reductions in organismal energy demands, which could be attained through modifications of body size or metabolic rate. We tested for convergence in energy demands and underlying traits by investigating livebearing fish (genus Poecilia) that have repeatedly colonized toxic, hydrogen sulphide-rich springs. We quantified variation in body size and routine metabolism across replicated sulphidic and non-sulphidic populations in nature, modelled total organismal energy demands, and conducted a common-garden experiment to test whether population differences had a genetic basis. Sulphidic populations generally exhibited smaller body sizes and lower routine metabolic rates compared to non-sulphidic populations, which together caused significant reductions in total organismal energy demands in extremophile populations. Although both mechanisms contributed to variation in organismal energy demands, variance partitioning indicated reductions of body size overall had a greater effect than reductions of routine metabolism. Finally, population differences in routine metabolism documented in natural populations were maintained in common-garden reared individuals, indicating evolved differences. In combination with other studies, these results suggest that reductions in energy demands may represent a common theme in adaptation to physiochemical stressors. Selection for reduced energy demand may particularly affect body size, which has implications for life history evolution in extreme environments. PMID:29077740

Effects of spatial subsidies and habitat structure on the foraging ecology and size of geckos

USGS Publications Warehouse

Briggs, Amy A.; Young, Hillary S.; McCauley, Douglas J.; Hathaway, Stacie A.; Dirzo, Rodolfo; Fisher, Robert N.

2012-01-01

While it is well established that ecosystem subsidies—the addition of energy, nutrients, or materials across ecosystem boundaries—can affect consumer abundance, there is less information available on how subsidy levels may affect consumer diet, body condition, trophic position, and resource partitioning among consumer species. There is also little information on whether changes in vegetation structure commonly associated with spatial variation in subsidies may play an important role in driving consumer responses to subsidies. To address these knowledge gaps, we studied changes in abundance, diet, trophic position, size, and body condition of two congeneric gecko species (Lepidodactylus spp.) that coexist in palm dominated and native (hereafter dicot dominated) forests across the Central Pacific. These forests differ trongly both in the amount of marine subsidies that they receive from seabird guano and carcasses, and in the physical structure of the habitat. Contrary to other studies, we found that subsidy level had no impact on the abundance of either gecko species; it also did not have any apparent effects on resource partitioning between species. However, it did affect body size, dietary composition, and trophic position of both species. Geckos in subsidized, dicot forests were larger, had higher body condition and more diverse diets, and occupied a much higher trophic position than geckos found in palm dominated, low subsidy level forests. Both direct variation in subsidy levels and associated changes in habitat structure appear to play a role in driving these responses. These results suggest that variation in subsidy levels may drive important behavioral responses in predators, even when their numerical response is limited. Strong changes in trophic position of consumers also suggest that subsidies may drive increasingly complex food webs, with longer overall food chain length.

Prey dispersal rate affects prey species composition and trait diversity in response to multiple predators in metacommunities.

PubMed

Howeth, Jennifer G; Leibold, Mathew A

2010-09-01

1. Recent studies indicate that large-scale spatial processes can alter local community structuring mechanisms to determine local and regional assemblages of predators and their prey. In metacommunities, this may occur when the functional diversity represented in the regional predator species pool interacts with the rate of prey dispersal among local communities to affect prey species diversity and trait composition at multiple scales. 2. Here, we test for effects of prey dispersal rate and spatially and temporally heterogeneous predation from functionally dissimilar predators on prey structure in pond mesocosm metacommunities. An experimental metacommunity consisted of three pond mesocosm communities supporting two differentially size-selective invertebrate predators and their zooplankton prey. In each metacommunity, two communities maintained constant predation and supported either Gyrinus sp. (Coleoptera) or Notonecta ungulata (Hemiptera) predators generating a spatial prey refuge while the third community supported alternating predation from Gyrinus sp. and N. ungulata generating a temporal prey refuge. Mesocosm metacommunities were connected at either low (0.7% day(-1)) or high (10% day(-1)) planktonic prey dispersal. The diversity, composition and body size of zooplankton prey were measured at local and regional (metacommunity) scales. 3. Metacommunities experiencing the low prey dispersal rate supported the greatest regional prey species diversity (H') and evenness (J'). Neither dispersal rate nor predation regime affected local prey diversity or evenness. The spatial prey refuge at low dispersal maintained the largest difference in species composition and body size diversity between communities under Gyrinus and Notonecta predation, suggesting that species sorting was operating at the low dispersal rate. There was no effect of dispersal rate on species diversity or body size distribution in the temporal prey refuge. 4. The frequency distribution, but not the range, of prey body sizes within communities depended upon prey dispersal rate and predator identity. Taken together, these results demonstrate that prey dispersal rate can moderate the strength of predation to influence prey species diversity and the local frequency distribution of prey traits in metacommunities supporting ecologically different predators.

Morphological plasticity reduces the effect of poor developmental conditions on fledging age in mourning doves

PubMed Central

Miller, David A.

2010-01-01

Developmental plasticity can be integral in adapting organisms to the environment experienced during growth. Adaptive plastic responses may be especially important in prioritizing development in response to stress during ontogeny. To evaluate this, I examined how developmental conditions for mourning doves related to early growth and how this affected fledging age, an important life-history transition for birds. The life history of mourning doves is consistent with strong selective pressure to minimize fledging age. Therefore, I predicted that in the face of nutritional stress associated with experimental brood-size increases, young would prioritize growth to structures that promote early fledging to reduce the effect of slowed overall growth on fledging age. Increasing brood size slowed overall structural growth of nestlings and affected the relative allocation of growth among different body parts. Total wing area was the best predictor of fledging age and individuals from larger broods had larger wings relative to overall body size. Although nestlings from larger broods fledged at later ages owing to slower overall growth, prioritization of wing growth reduced this effect by an estimated 1.6 days relative to the delay if plasticity among body parts had not occurred. This was an 11 per cent reduction in the predicted developmental time it took to reach this important life-history transition. Results demonstrate that preferential allocation to wing growth can affect the timing of this life-history transition and that morphological plasticity during development can have adaptive near-term effects during avian development. PMID:20129984

The Exposure Effects of Online Model Pictures and Weight-Related Persuasive Messages on Women's Weight-Loss Planned Behaviors.

PubMed

Pan, Wenjing; Peña, Jorge

2017-10-01

This study examined how exposure to pictures of women with different body sizes (thin, obese), physical attractiveness levels (attractive, unattractive), along with exposure to weight-related messages (pro-anorexia, anti-anorexia) embedded in a fashion website affected female participants' planned behavior toward weight loss. Participants exposed to attractive model pictures showed higher intentions, attitudes, and subjective norms to lose weight compared with unattractive models. Additionally, participants exposed to thin and attractive model pictures indicated the highest attitudes and self-efficacy to lose weight, whereas those exposed to thin and unattractive model pictures indicated the lowest. Furthermore, weight-related messages moderated the effect of model appearance (body size and attractiveness) on controllability of weight-loss activities. However, website pictures' body size differences had no main effects on planned behavior toward weight loss. These effects are discussed in the light of social comparison mechanisms.

Metabolism drives distribution and abundance in extremophile fish

PubMed Central

McHugh, Peter A.; Glover, Chris N.; McIntosh, Angus R.

2017-01-01

Differences in population density between species of varying size are frequently attributed to metabolic rates which are assumed to scale with body size with a slope of 0.75. This assumption is often criticised on the grounds that 0.75 scaling of metabolic rate with body size is not universal and can vary significantly depending on species and life-history. However, few studies have investigated how interspecific variation in metabolic scaling relationships affects population density in different sized species. Here we predict inter-specific differences in metabolism from niche requirements, thereby allowing metabolic predictions of species distribution and abundance at fine spatial scales. Due to the differences in energetic efficiency required along harsh-benign gradients, an extremophile fish (brown mudfish, Neochanna apoda) living in harsh environments had slower metabolism, and thus higher population densities, compared to a fish species (banded kōkopu, Galaxias fasciatus) in physiologically more benign habitats. Interspecific differences in the intercepts for the relationship between body and density disappeared when species mass-specific metabolic rates, rather than body sizes, were used to predict density, implying population energy use was equivalent between mudfish and kōkopu. Nevertheless, despite significant interspecific differences in the slope of the metabolic scaling relationships, mudfish and kōkopu had a common slope for the relationship between body size and population density. These results support underlying logic of energetic equivalence between different size species implicit in metabolic theory. However, the precise slope of metabolic scaling relationships, which is the subject of much debate, may not be a reliable indicator of population density as expected under metabolic theory. PMID:29176819

Temperature-dependent body size effects determine population responses to climate warming.

PubMed

Lindmark, Max; Huss, Magnus; Ohlberger, Jan; Gårdmark, Anna

2018-02-01

Current understanding of animal population responses to rising temperatures is based on the assumption that biological rates such as metabolism, which governs fundamental ecological processes, scale independently with body size and temperature, despite empirical evidence for interactive effects. Here, we investigate the consequences of interactive temperature- and size scaling of vital rates for the dynamics of populations experiencing warming using a stage-structured consumer-resource model. We show that interactive scaling alters population and stage-specific responses to rising temperatures, such that warming can induce shifts in population regulation and stage-structure, influence community structure and govern population responses to mortality. Analysing experimental data for 20 fish species, we found size-temperature interactions in intraspecific scaling of metabolic rate to be common. Given the evidence for size-temperature interactions and the ubiquity of size structure in animal populations, we argue that accounting for size-specific temperature effects is pivotal for understanding how warming affects animal populations and communities. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Developmental model of static allometry in holometabolous insects.

PubMed

Shingleton, Alexander W; Mirth, Christen K; Bates, Peter W

2008-08-22

The regulation of static allometry is a fundamental developmental process, yet little is understood of the mechanisms that ensure organs scale correctly across a range of body sizes. Recent studies have revealed the physiological and genetic mechanisms that control nutritional variation in the final body and organ size in holometabolous insects. The implications these mechanisms have for the regulation of static allometry is, however, unknown. Here, we formulate a mathematical description of the nutritional control of body and organ size in Drosophila melanogaster and use it to explore how the developmental regulators of size influence static allometry. The model suggests that the slope of nutritional static allometries, the 'allometric coefficient', is controlled by the relative sensitivity of an organ's growth rate to changes in nutrition, and the relative duration of development when nutrition affects an organ's final size. The model also predicts that, in order to maintain correct scaling, sensitivity to changes in nutrition varies among organs, and within organs through time. We present experimental data that support these predictions. By revealing how specific physiological and genetic regulators of size influence allometry, the model serves to identify developmental processes upon which evolution may act to alter scaling relationships.

Should Body Size Categories Be More Common in Endurance Running Events?

PubMed

Buresh, Robert

2018-05-01

Thousands of endurance running events are held each year in the United States, and most of them use age and sex categories to account for documented effects of those factors on running performance. However, most running events do not provide categories of body mass, despite abundant evidence that it, too, dramatically influences endurance running performance. The purposes of this article are to (1) discuss how body mass affects endurance running performance, (2) explain several mechanisms through which body mass influences endurance running performance, and (3) suggest possible ways in which body mass might be categorized in endurance running events.

Intra-specific downsizing of frugivores affects seed germination of fleshy-fruited plant species

NASA Astrophysics Data System (ADS)

Pérez-Méndez, Néstor; Rodríguez, Airam; Nogales, Manuel

2018-01-01

The loss of largest-bodied individuals within species of frugivorous animals is one of the major consequences of defaunation. The gradual disappearance of large-bodied frugivores is expected to entail a parallel deterioration in seed dispersal functionality if the remaining smaller-sized individuals are not so effective as seed dispersers. While the multiple impacts of the extinction of large bodied species have been relatively well studied, the impact of intraspecific downsizing (i.e. the extinction of large individuals within species) on seed dispersal has rarely been evaluated. Here we experimentally assessed the impact of body-size reduction in the frugivorous lizard Gallotia galloti (Lacertidae), an endemic species of the Canary Islands, on the seed germination patterns of two fleshy-fruited plant species (Rubia fruticosa and Withania aristata). Seed germination curves and the proportions of germinated seeds were compared for both plant species after being defecated by large-sized individuals and small-sized individuals. The data show that seeds of W. aristata defecated by larger-sized lizards germinated faster and in a higher percentage than those defecated by small-sized lizards, while no differences were found for R. fruticosa seeds. Our results suggest that disappearance of the largest individuals of frugivorous species may impair recruitment of some plant species by worsening seed germination. They also warn us of a potential cryptic loss of seed dispersal functionality on defaunated ecosystems, even when frugivorous species remain abundant.

Body ownership promotes visual awareness.

PubMed

van der Hoort, Björn; Reingardt, Maria; Ehrsson, H Henrik

2017-08-17

The sense of ownership of one's body is important for survival, e.g., in defending the body against a threat. However, in addition to affecting behavior, it also affects perception of the world. In the case of visuospatial perception, it has been shown that the sense of ownership causes external space to be perceptually scaled according to the size of the body. Here, we investigated the effect of ownership on another fundamental aspect of visual perception: visual awareness. In two binocular rivalry experiments, we manipulated the sense of ownership of a stranger's hand through visuotactile stimulation while that hand was one of the rival stimuli. The results show that ownership, but not mere visuotactile stimulation, increases the dominance of the hand percept. This effect is due to a combination of longer perceptual dominance durations and shorter suppression durations. Together, these results suggest that the sense of body ownership promotes visual awareness.

Body ownership promotes visual awareness

PubMed Central

Reingardt, Maria; Ehrsson, H Henrik

2017-01-01

The sense of ownership of one’s body is important for survival, e.g., in defending the body against a threat. However, in addition to affecting behavior, it also affects perception of the world. In the case of visuospatial perception, it has been shown that the sense of ownership causes external space to be perceptually scaled according to the size of the body. Here, we investigated the effect of ownership on another fundamental aspect of visual perception: visual awareness. In two binocular rivalry experiments, we manipulated the sense of ownership of a stranger’s hand through visuotactile stimulation while that hand was one of the rival stimuli. The results show that ownership, but not mere visuotactile stimulation, increases the dominance of the hand percept. This effect is due to a combination of longer perceptual dominance durations and shorter suppression durations. Together, these results suggest that the sense of body ownership promotes visual awareness. PMID:28826500

Analysis of copy number variants by three detection algorithms and their association with body size in horses.

PubMed

Metzger, Julia; Philipp, Ute; Lopes, Maria Susana; da Camara Machado, Artur; Felicetti, Michela; Silvestrelli, Maurizio; Distl, Ottmar

2013-07-18

Copy number variants (CNVs) have been shown to play an important role in genetic diversity of mammals and in the development of many complex phenotypic traits. The aim of this study was to perform a standard comparative evaluation of CNVs in horses using three different CNV detection programs and to identify genomic regions associated with body size in horses. Analysis was performed using the Illumina Equine SNP50 genotyping beadchip for 854 horses. CNVs were detected by three different algorithms, CNVPartition, PennCNV and QuantiSNP. Comparative analysis revealed 50 CNVs that affected 153 different genes mainly involved in sensory perception, signal transduction and cellular components. Genome-wide association analysis for body size showed highly significant deleted regions on ECA1, ECA8 and ECA9. Homologous regions to the detected CNVs on ECA1 and ECA9 have also been shown to be correlated with human height. Comparative analysis of CNV detection algorithms was useful to increase the specificity of CNV detection but had certain limitations dependent on the detection tool. GWAS revealed genome-wide associated CNVs for body size in horses.

Body size drives allochthony in food webs of tropical rivers.

PubMed

Jardine, Timothy D; Rayner, Thomas S; Pettit, Neil E; Valdez, Dominic; Ward, Douglas P; Lindner, Garry; Douglas, Michael M; Bunn, Stuart E

2017-02-01

Food web subsidies from external sources ("allochthony") can support rich biological diversity and high secondary and tertiary production in aquatic systems, even those with low rates of primary production. However, animals vary in their degree of dependence on these subsidies. We examined dietary sources for aquatic animals restricted to refugial habitats (waterholes) during the dry season in Australia's wet-dry tropics, and show that allochthony is strongly size dependent. While small-bodied fishes and invertebrates derived a large proportion of their diet from autochthonous sources within the waterhole (phytoplankton, periphyton, or macrophytes), larger animals, including predatory fishes and crocodiles, demonstrated allochthony from seasonally inundated floodplains, coastal zones or the surrounding savanna. Autochthony declined roughly 10% for each order of magnitude increase in body size. The largest animals in the food web, estuarine crocodiles (Crocodylus porosus), derived ~80% of their diet from allochthonous sources. Allochthony enables crocodiles and large predatory fish to achieve high biomass, countering empirically derived expectations for negative density vs. body size relationships. These results highlight the strong degree of connectivity that exists between rivers and their floodplains in systems largely unaffected by river regulation or dams and levees, and how large iconic predators could be disproportionately affected by these human activities.

Movement ecology: size-specific behavioral response of an invasive snail to food availability.

PubMed

Snider, Sunny B; Gilliam, James F

2008-07-01

Immigration, emigration, migration, and redistribution describe processes that involve movement of individuals. These movements are an essential part of contemporary ecological models, and understanding how movement is affected by biotic and abiotic factors is important for effectively modeling ecological processes that depend on movement. We asked how phenotypic heterogeneity (body size) and environmental heterogeneity (food resource level) affect the movement behavior of an aquatic snail (Tarebia granifera), and whether including these phenotypic and environmental effects improves advection-diffusion models of movement. We postulated various elaborations of the basic advection diffusion model as a priori working hypotheses. To test our hypotheses we measured individual snail movements in experimental streams at high- and low-food resource treatments. Using these experimental movement data, we examined the dependency of model selection on resource level and body size using Akaike's Information Criterion (AIC). At low resources, large individuals moved faster than small individuals, producing a platykurtic movement distribution; including size dependency in the model improved model performance. In stark contrast, at high resources, individuals moved upstream together as a wave, and body size differences largely disappeared. The model selection exercise indicated that population heterogeneity is best described by the advection component of movement for this species, because the top-ranked model included size dependency in advection, but not diffusion. Also, all probable models included resource dependency. Thus population and environmental heterogeneities both influence individual movement behaviors and the population-level distribution kernels, and their interaction may drive variation in movement behaviors in terms of both advection rates and diffusion rates. A behaviorally informed modeling framework will integrate the sentient response of individuals in terms of movement and enhance our ability to accurately model ecological processes that depend on animal movement.

Reproductive performance and gestational effort in relation to dietary fatty acids in guinea pigs.

PubMed

Nemeth, Matthias; Millesi, Eva; Siutz, Carina; Wagner, Karl-Heinz; Quint, Ruth; Wallner, Bernard

2017-01-01

Dietary saturated (SFAs) and polyunsaturated (PUFAs) fatty acids can highly affect reproductive functions by providing additional energy, modulating the biochemical properties of tissues, and hormone secretions. In precocial mammals such as domestic guinea pigs the offspring is born highly developed. Gestation might be the most critical reproductive period in this species and dietary fatty acids may profoundly influence the gestational effort. We therefore determined the hormonal status at conception, the reproductive success, and body mass changes during gestation in guinea pigs maintained on diets high in PUFAs or SFAs, or a control diet. The diets significantly affected the females' plasma fatty acid status at conception, while cortisol and estrogen levels did not differ among groups. SFA females exhibited a significantly lower body mass and litter size, while the individual birth mass of pups did not differ among groups and a general higher pup mortality rate in larger litters was diminished by PUFAs and SFAs. The gestational effort, determined by a mother's body mass gain during gestation, increased with total litter mass, whereas this increase was lowest in SFA and highest in PUFA individuals. The mother's body mass after parturition did not differ among groups and was positively affected by the total litter mass in PUFA females. While SFAs reduce the litter size, but also the gestational effort as a consequence, PUFA supplementation may contribute to an adjustment of energy accumulations to the total litter mass, which may both favor a mother's body condition at parturition and perhaps increase the offspring survival at birth.

Mest but Not MiR-335 Affects Skeletal Muscle Growth and Regeneration

PubMed Central

Hiramuki, Yosuke; Sato, Takahiko; Furuta, Yasuhide; Surani, M. Azim; Sehara-Fujisawa, Atsuko

2015-01-01

When skeletal muscle fibers are injured, they regenerate and grow until their sizes are adjusted to surrounding muscle fibers and other relevant organs. In this study, we examined whether Mest, one of paternally expressed imprinted genes that regulates body size during development, and miR-335 located in the second intron of the Mest gene play roles in muscle regeneration. We generated miR-335-deficient mice, and found that miR-335 is a paternally expressed imprinted microRNA. Although both Mest and miR-335 are highly expressed during muscle development and regeneration, only Mest+/- (maternal/paternal) mice show retardation of body growth. In addition to reduced body weight in Mest+/-; DMD-null mice, decreased muscle growth was observed in Mest+/- mice during cardiotoxin-induced regeneration, suggesting roles of Mest in muscle regeneration. Moreover, expressions of H19 and Igf2r, maternally expressed imprinted genes were affected in tibialis anterior muscle of Mest+/-; DMD-null mice compared to DMD-null mice. Thus, Mest likely mediates muscle regeneration through regulation of imprinted gene networks in skeletal muscle. PMID:26098312

Mest but Not MiR-335 Affects Skeletal Muscle Growth and Regeneration.

PubMed

Hiramuki, Yosuke; Sato, Takahiko; Furuta, Yasuhide; Surani, M Azim; Sehara-Fujisawa, Atsuko

2015-01-01

When skeletal muscle fibers are injured, they regenerate and grow until their sizes are adjusted to surrounding muscle fibers and other relevant organs. In this study, we examined whether Mest, one of paternally expressed imprinted genes that regulates body size during development, and miR-335 located in the second intron of the Mest gene play roles in muscle regeneration. We generated miR-335-deficient mice, and found that miR-335 is a paternally expressed imprinted microRNA. Although both Mest and miR-335 are highly expressed during muscle development and regeneration, only Mest+/- (maternal/paternal) mice show retardation of body growth. In addition to reduced body weight in Mest+/-; DMD-null mice, decreased muscle growth was observed in Mest+/- mice during cardiotoxin-induced regeneration, suggesting roles of Mest in muscle regeneration. Moreover, expressions of H19 and Igf2r, maternally expressed imprinted genes were affected in tibialis anterior muscle of Mest+/-; DMD-null mice compared to DMD-null mice. Thus, Mest likely mediates muscle regeneration through regulation of imprinted gene networks in skeletal muscle.

Bone health in Down syndrome.

PubMed

García-Hoyos, Marta; Riancho, José Antonio; Valero, Carmen

2017-07-21

Patients with Down syndrome have a number of risk factors that theoretically could predispose them to osteoporosis, such as early aging, development disorders, reduced physical activity, limited sun exposure, frequent comorbidities and use of drug therapies which could affect bone metabolism. In addition, the bone mass of these people may be affected by their anthropometric and body composition peculiarities. In general terms, studies in adults with Down syndrome reported that these people have lower areal bone mineral density (g/cm 2 ) than the general population. However, most of them have not taken the smaller bone size of people with Down syndrome into account. In fact, when body mineral density is adjusted by bone size and we obtain volumetric body mineral density (g/cm 3 ), the difference between both populations disappears. On the other hand, although people with Down syndrome have risk factor of hypovitaminosis D, the results of studies regarding 25(OH)D in this population are not clear. Likewise, the studies about biochemical bone markers or the prevalence of fractures are not conclusive. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

Efforts in Preparation for Jack Validation.

DTIC Science & Technology

1997-12-01

clothing, equipment attached to the body, age, or physical health. The skeleton’s size, structure, and proportions are affected by age, exercise ...things such as genetics, exercise , and dietary habit (Bailey, Malina, & Rasmussen, 1978). VIRTUAL HUMAN MODELS A virtual human models only a subset of...artistically modeled) surfaces. - Somatotype modeling is not considered. To understand what this implies, consider scaling the body using an average

Molecular Characterization of Bovine SMO Gene and Effects of Its Genetic Variations on Body Size Traits in Qinchuan Cattle (Bos taurus).

PubMed

Zhang, Ya-Ran; Gui, Lin-Sheng; Li, Yao-Kun; Jiang, Bi-Jie; Wang, Hong-Cheng; Zhang, Ying-Ying; Zan, Lin-Sen

2015-07-27

Smoothened (Smo)-mediated Hedgehog (Hh) signaling pathway governs the patterning, morphogenesis and growth of many different regions within animal body plans. This study evaluated the effects of genetic variations of the bovine SMO gene on economically important body size traits in Chinese Qinchuan cattle. Altogether, eight single nucleotide polymorphisms (SNPs: 1-8) were identified and genotyped via direct sequencing covering most of the coding region and 3'UTR of the bovine SMO gene. Both the p.698Ser.>Ser. synonymous mutation resulted from SNP1 and the p.700Ser.>Pro. non-synonymous mutation caused by SNP2 mapped to the intracellular C-terminal tail of bovine Smo protein; the other six SNPs were non-coding variants located in the 3'UTR. The linkage disequilibrium was analyzed, and five haplotypes were discovered in 520 Qinchuan cattle. Association analyses showed that SNP2, SNP3/5, SNP4 and SNP6/7 were significantly associated with some body size traits (p < 0.05) except SNP1/8 (p > 0.05). Meanwhile, cattle with wild-type combined haplotype Hap1/Hap1 had significantly (p < 0.05) greater body length than those with Hap2/Hap2. Our results indicate that variations in the SMO gene could affect body size traits of Qinchuan cattle, and the wild-type haplotype Hap1 together with the wild-type alleles of these detected SNPs in the SMO gene could be used to breed cattle with superior body size traits. Therefore, our results could be helpful for marker-assisted selection in beef cattle breeding programs.

Molecular Characterization of Bovine SMO Gene and Effects of Its Genetic Variations on Body Size Traits in Qinchuan Cattle (Bos taurus)

PubMed Central

Zhang, Ya-Ran; Gui, Lin-Sheng; Li, Yao-Kun; Jiang, Bi-Jie; Wang, Hong-Cheng; Zhang, Ying-Ying; Zan, Lin-Sen

2015-01-01

Smoothened (Smo)-mediated Hedgehog (Hh) signaling pathway governs the patterning, morphogenesis and growth of many different regions within animal body plans. This study evaluated the effects of genetic variations of the bovine SMO gene on economically important body size traits in Chinese Qinchuan cattle. Altogether, eight single nucleotide polymorphisms (SNPs: 1–8) were identified and genotyped via direct sequencing covering most of the coding region and 3ʹUTR of the bovine SMO gene. Both the p.698Ser.>Ser. synonymous mutation resulted from SNP1 and the p.700Ser.>Pro. non-synonymous mutation caused by SNP2 mapped to the intracellular C-terminal tail of bovine Smo protein; the other six SNPs were non-coding variants located in the 3ʹUTR. The linkage disequilibrium was analyzed, and five haplotypes were discovered in 520 Qinchuan cattle. Association analyses showed that SNP2, SNP3/5, SNP4 and SNP6/7 were significantly associated with some body size traits (p < 0.05) except SNP1/8 (p > 0.05). Meanwhile, cattle with wild-type combined haplotype Hap1/Hap1 had significantly (p < 0.05) greater body length than those with Hap2/Hap2. Our results indicate that variations in the SMO gene could affect body size traits of Qinchuan cattle, and the wild-type haplotype Hap1 together with the wild-type alleles of these detected SNPs in the SMO gene could be used to breed cattle with superior body size traits. Therefore, our results could be helpful for marker-assisted selection in beef cattle breeding programs. PMID:26225956

The evolutionary puzzle of egg size, oxygenation and parental care in aquatic environments.

PubMed

Braga Goncalves, Ines; Ahnesjö, Ingrid; Kvarnemo, Charlotta

2015-08-22

Offspring fitness generally improves with increasing egg size. Yet, eggs of most aquatic organisms are small. A common but largely untested assumption is that larger embryos require more oxygen than they can acquire through diffusion via the egg surface, constraining egg size evolution. However, we found no detrimental effects of large egg size on embryo growth and survival under hypoxic conditions. We tested this in the broad-nosed pipefish, Syngnathus typhle, whose males provide extensive care (nourishment, osmoregulation and oxygenation) to their young in a brood pouch on their bodies. We took advantage of this species' pronounced variation in egg size, correlating positively with female size, and tested the effect of hypoxia (40% dissolved oxygen) versus fully oxygenated (100%) water on embryo size and survival of large versus small eggs after 18 days of paternal brooding. Egg size did not affect embryo survival, regardless of O2 treatment. While hypoxia affected embryo size negatively, both large and small eggs showed similar reductions in growth. Males in hypoxia ventilated more and males with large eggs swam more, but neither treatment affected their position in the water column. Overall, our results call into question the most common explanation for constrained egg size evolution in aquatic environments. © 2015 The Author(s).

The evolutionary puzzle of egg size, oxygenation and parental care in aquatic environments

PubMed Central

Braga Goncalves, Ines; Ahnesjö, Ingrid; Kvarnemo, Charlotta

2015-01-01

Offspring fitness generally improves with increasing egg size. Yet, eggs of most aquatic organisms are small. A common but largely untested assumption is that larger embryos require more oxygen than they can acquire through diffusion via the egg surface, constraining egg size evolution. However, we found no detrimental effects of large egg size on embryo growth and survival under hypoxic conditions. We tested this in the broad-nosed pipefish, Syngnathus typhle, whose males provide extensive care (nourishment, osmoregulation and oxygenation) to their young in a brood pouch on their bodies. We took advantage of this species' pronounced variation in egg size, correlating positively with female size, and tested the effect of hypoxia (40% dissolved oxygen) versus fully oxygenated (100%) water on embryo size and survival of large versus small eggs after 18 days of paternal brooding. Egg size did not affect embryo survival, regardless of O2 treatment. While hypoxia affected embryo size negatively, both large and small eggs showed similar reductions in growth. Males in hypoxia ventilated more and males with large eggs swam more, but neither treatment affected their position in the water column. Overall, our results call into question the most common explanation for constrained egg size evolution in aquatic environments. PMID:26290070

Influence of body condition on reproductive output in the guinea pig.

PubMed

Michel, Catherine Louise; Bonnet, Xavier

2012-01-01

Reproduction is expensive. Substantial body reserves (i.e. high body condition) are usually required for females to undertake offspring production. In many vertebrates, maternal body condition positively influences reproductive output, and emaciated individuals skip reproduction. However, the impact of extremely high body condition, more specifically obesity, on animal reproductive performance remains poorly understood and research has generated contradictory results. For instance, obesity negatively affects fertility in women, but does not influence reproductive capacity or reproductive output in laboratory rodents. We examined the influence of high body condition on reproductive status and reproductive output in the guinea pig. In captivity, when fed ad libitum, guinea pigs store large amounts of fat tissues and exhibit a tendency for obesity. Our results show that obesity negatively affected reproduction in this species: both the proportion of fertile females and litter size were lower in the fattest females. Therefore, guinea pigs may represent suitable organisms to better understand the negative effect of obesity on reproduction. Copyright © 2011 Wiley Periodicals, Inc., A Wiley Company.

Individual variation affects departure rate from the natal pond in an ephemeral pond-breeding anuran

USGS Publications Warehouse

Chelgren, N.D.; Rosenberg, D.K.; Heppell, S.S.; Gitelman, A.I.

2008-01-01

Frogs exhibit extreme plasticity and individual variation in growth and behavior during metamorphosis, driven by interactions of intrinsic state factors and extrinsic environmental factors. In northern red-legged frogs (Rana aurora Baird and Girard, 1852), we studied the timing of departure from the natal pond as it relates to date and size of individuals at metamorphosis in the context of environmental uncertainty. To affect body size at metamorphosis, we manipulated food availability during the larval stage for a sample (317) of 1045 uniquely marked individuals and released them at their natal ponds as newly metamorphosed frogs. We recaptured 34% of marked frogs in pitfall traps as they departed and related the timing of their initial terrestrial movements to individual properties using a time-to-event model. Median age at first capture was 4 and 9 days postmetamorphosis at two sites. The rate of departure was positively related to body size and to date of metamorphosis. Departure rate was strongly negatively related to time elapsed since rainfall, and this effect was diminished for smaller and later metamorphosing frogs. Individual variation in metamorphic traits thus affects individuals' responses to environmental variability, supporting a behavioral link with variation in survival associated with these same metamorphic traits. ?? 2008 NRC.

Dissociating object-based from egocentric transformations in mental body rotation: effect of stimuli size.

PubMed

Habacha, Hamdi; Moreau, David; Jarraya, Mohamed; Lejeune-Poutrain, Laure; Molinaro, Corinne

2018-01-01

The effect of stimuli size on the mental rotation of abstract objects has been extensively investigated, yet its effect on the mental rotation of bodily stimuli remains largely unexplored. Depending on the experimental design, mentally rotating bodily stimuli can elicit object-based transformations, relying mainly on visual processes, or egocentric transformations, which typically involve embodied motor processes. The present study included two mental body rotation tasks requiring either a same-different or a laterality judgment, designed to elicit object-based or egocentric transformations, respectively. Our findings revealed shorter response times for large-sized stimuli than for small-sized stimuli only for greater angular disparities, suggesting that the more unfamiliar the orientations of the bodily stimuli, the more stimuli size affected mental processing. Importantly, when comparing size transformation times, results revealed different patterns of size transformation times as a function of angular disparity between object-based and egocentric transformations. This indicates that mental size transformation and mental rotation proceed differently depending on the mental rotation strategy used. These findings are discussed with respect to the different spatial manipulations involved during object-based and egocentric transformations.

Larger Daphnia at lower temperature: a role for cell size and genome configuration?

PubMed

Jalal, Marwa; Wojewodzic, Marcin W; Laane, Carl Morten M; Hessen, Dag O

2013-09-01

Experiments with Daphnia magna and Daphnia pulex raised at 10 and 20 °C yielded larger adult size at the lower temperature. This must reflect increased cell size, increased cell numbers, or a combination of both. As it is difficult to achieve good estimates on cell size in crustaceans, we, therefore, measured nucleus and genome size using flow cytometry at 10 and 20 °C. DNA was stained with propidium iodide, ethidium bromide, and DAPI. Both nucleus and genome size estimates were elevated at 10 °C compared with 20 °C, suggesting that larger body size at low temperature could partly be accredited to an enlarged nucleus and thus cell size. Confocal microscopy observations confirmed the staining properties of fluorochromes. As differences in nucleotide numbers in response of growth temperature within a life span is unlikely, these results seem accredited to changed DNA-fluorochrome binding properties, presumably reflecting increased DNA condensation at low temperature. This implies that genome size comparisons may be impacted by ambient temperature in ectotherms. It also suggests that temperature-induced structural changes in the genome could affect cell size and for some species even body size.

Heavy resistance training and peri-exercise ingestion of a multi-ingredient ergogenic nutritional supplement in males: effects on body composition, muscle performance and markers of muscle protein synthesis.

PubMed

Spillane, Mike; Schwarz, Neil; Willoughby, Darryn S

2014-12-01

This study determined the effects of heavy resistance training and peri-exercise ergogenic multi-ingredient nutritional supplement ingestion on blood and skeletal markers of muscle protein synthesis (MPS), body composition, and muscle performance. Twenty-four college-age males were randomly assigned to either a multi-ingredient SizeOn Maximum Performance (SIZE) or protein/carbohydrate/creatine (PCC) comparator supplement group in a double-blind fashion. Body composition and muscle performance were assessed, and venous blood samples and muscle biopsies were obtained before and after 6 weeks of resistance training and supplementation. Data were analyzed by 2-way ANOVA (p ≤ 0.05). Total body mass, body water, and fat mass were not differentially affected (p > 0.05). However, fat-free mass was significantly increased in both groups in response to resistance training (p = 0.037). Lower-body muscle strength (p = 0.029) and endurance (p = 0.027) were significantly increased with resistance training, but not supplementation (p > 0.05). Serum insulin, IGF-1, GH, and cortisol were not differentially affected (p > 0.05). Muscle creatine content was significantly increased in both groups from supplementation (p = 0.044). Total muscle protein (p = 0.038), MHC 1 (p = 0.041), MHC 2A, (p = 0.029), total IRS- (p = 0.041), and total Akt (p = 0.011) were increased from resistance training, but not supplementation. In response to heavy resistance training when compared to PCC, the peri-exercise ingestion of SIZE did not preferentially improve body composition, muscle performance, and markers indicative of MPS. Key pointsIn response to 42 days of heavy resistance training and either SizeOn Maximum Performance or protein/carbohydrate/creatine supplementation, similar increases in muscle mass and strength in both groups occurred; however, the increases were not different between supplement groups.The supplementation of SizeOn Maximum Performance had no preferential effect on augmenting serum insulin, IGF-1, and GH, or in decreasing cortisol.While resistance training was effective in increasing total creatine content in skeletal muscle, myofibrillar protein, and the content of total IRS-1 and Akt, it was not preferentially due to SizeOn Maximum Performance supplementation.At the daily dose of 50 g, SizeOn Maximum Performance supplementation for 42 days combined with resistance training does not increases muscle mass and strength due to its ability to elevate serum hormones and growth factors or in its ability to augment skeletal muscle signaling pathway markers indicative of muscle protein synthesis when compared to an equivalent daily dose of protein/carbohydrate/creatine.

Thermoregulation of a temperate reptile in a forested habitat.

PubMed

Corkery, Ilse; Bell, Ben D; Nelson, Nicola J

2018-04-01

A major focus in zoology is to understand the phenotypic responses of animals to environmental variation. This is particularly important when dealing with ectotherms in a thermally heterogenous environment. We measured body temperatures of a free-ranging, medium sized temperate reptile, the tuatara, Sphenodon punctatus, to investigate its thermal opportunities and the degree to which the animal actively regulates its body temperature. We found high variation in body temperature between individuals, but this variation could not be attributed to sex or body size. However, variation among individuals in timing of burrow use did affect body temperature and in one of the years studied tuatara were found to be more effective in their thermoregulation when sharing a burrow with a seabird (Pachyptila turtur). The strength of this study is that it includes both biotic and behavioural components of the thermal environment of a temperate reptile, areas which are often missing from thermal studies that focus on the abiotic aspects. Copyright © 2018 Elsevier GmbH. All rights reserved.

Ornament Complexity Is Correlated with Sexual Selection: (A Comment on Raia et al., "Cope's Rule and the Universal Scaling Law of Ornament Complexity").

PubMed

Holman, Luke; Bro-Jørgensen, Jakob

2016-08-01

Raia et al. propose that the evolution of the shape and complexity of animal ornaments (e.g., deer antlers) can be explained by interspecific variation in body size and is not influenced by sexual selection. They claim to show that ornament complexity is related to body size by an 0.25-power law and argue that this finding precludes a role for sexual selection in the evolution of ornament complexity. However, their study does not test alternative hypotheses and mismeasures antler shape allometry by omitting much of the published data. We show that an index of sexual selection (sexual size dimorphism) is positively correlated with size-corrected antler complexity and that the allometric slope of complexity is substantially greater than 0.25, contra Raia et al. We conclude that sexual selection and physical constraints both affect the evolution of antler shape.

Mammal extinctions, body size, and paleotemperature

USGS Publications Warehouse

Bown, T.M.; Holroyd, P.A.; Rose, K.D.

1994-01-01

There is a general inverse relationship between the natural logarithm of tooth area (a body size indicator) of some fossil mammals and paleotemperature during approximately 2.9 million years of the early Eocene in the Bighorn Basin of northwest Wyoming. When mean temperatures became warmer, tooth areas tended to become smaller. During colder times, larger species predominated; these generally became larger or remained the same size. Paleotemperature trends also markedly affected patterns of local (and, perhaps, regional) extinction and immigration. New species appeared as immigrants during or near the hottest (smaller forms) and coldest (larger forms) intervals. Paleotemperature trend reversals commonly resulted in the ultimate extinction of both small forms (during cooling intervals) and larger forms (during warming intervals). These immigrations and extinctions mark faunal turnovers that were also modulated by sharp increases in sediment accumulation rate.

Distribution pattern and number of ticks on lizards.

PubMed

Dudek, Krzysztof; Skórka, Piotr; Sajkowska, Zofia Anna; Ekner-Grzyb, Anna; Dudek, Monika; Tryjanowski, Piotr

2016-02-01

The success of ectoparasites depends primarily on the site of attachment and body condition of their hosts. Ticks usually tend to aggregate on vertebrate hosts in specific areas, but the distribution pattern may depend on host body size and condition, sex, life stage or skin morphology. Here, we studied the distribution of ticks on lizards and tested the following hypothesis: occurrence or high abundance of ticks is confined with body parts with smaller scales and larger interscalar length because such sites should provide ticks with superior attachment conditions. This study was performed in field conditions in central Poland in 2008-2011. In total, 500 lizards (Lacerta agilis) were caught and 839 ticks (Ixodes ricinus, larvae and nymphs) were collected from them. Using generalised linear mixed models, we found that the ticks were most abundant on forelimbs and their axillae, with 90% of ticks attached there. This part of the lizard body and the region behind the hindlimb were covered by the smallest scales with relatively wide gaps between them. This does not fully support our hypothesis that ticks prefer locations with easy access to skin between scales, because it does not explain why so few ticks were in the hindlimb area. We found that the abundance of ticks was positively correlated with lizard body size index (snout-vent length). Tick abundance was also higher in male and mature lizards than in female and young individuals. Autotomy had no effect on tick abundance. We found no correlation between tick size and lizard morphology, sex, autotomy and body size index. The probability of occurrence of dead ticks was positively linked with the total number of ticks on the lizard but there was no relationship between dead tick presence and lizard size, sex or age. Thus lizard body size and sex are the major factors affecting the abundance of ticks, and these parasites are distributed nearly exclusively on the host's forelimbs and their axillae. Copyright © 2015 Elsevier GmbH. All rights reserved.

Body size affects the predatory interactions between introduced American Bullfrogs (Rana catesbeiana) and native anurans in China: An experimental study

USGS Publications Warehouse

Wang, Y.; Guo, Z.; Pearl, C.A.; Li, Y.

2007-01-01

Introduced American Bullfrogs (Rana catesbeiana) have established breeding populations in several provinces in China since their introduction in 1959. Although Bullfrogs are viewed as a potentially important predator of Chinese native anurans, their impacts in the field are difficult to quantify. We used two experiments to examine factors likely to mediate Bullfrog predation on native anurans. First, we examined effects of Bullfrog size and sex on daily consumption of a common Chinese native (Rana limnocharis). Second, we examined whether Bullfrogs consumed similar proportions of four Chinese natives: Black-Spotted Pond Frog (Rana nigromaculata), Green Pond Frog (Rana plancyi plancyi), Rice Frog (R. limnocharis), and Zhoushan Toad (Bufo bufo gargarizans). We found that larger Rana catesbeiana consumed more R. limnocharis per day than did smaller R. catesbeiana, and that daily consumption of R. limnocharis was positively related to R. catesbeiana body size. When provided with adults of four anurans that differed significantly in body size, R. catesbeiana consumed more individuals of the smallest species (R. limnocharis). However, when provided with similarly sized juveniles of the same four species, R. catesbeiana did not consume any species more than expected by chance. Our results suggest that body size plays an important role in the predatory interactions between R. catesbeiana and Chinese native anurans and that, other things being equal, smaller species and individuals are at greater risk of predation by R. catesbeiana. Copyright 2007 Society for the Study of Amphibians and Reptiles.

Mechanisms regulating nutrition-dependent developmental plasticity through organ-specific effects in insects

PubMed Central

Koyama, Takashi; Mendes, Cláudia C.; Mirth, Christen K.

2013-01-01

Nutrition, via the insulin/insulin-like growth factor (IIS)/Target of Rapamycin (TOR) signaling pathway, can provide a strong molding force for determining animal size and shape. For instance, nutrition induces a disproportionate increase in the size of male horns in dung and rhinoceros beetles, or mandibles in staghorn or horned flour beetles, relative to body size. In these species, well-fed male larvae produce adults with greatly enlarged horns or mandibles, whereas males that are starved or poorly fed as larvae bear much more modest appendages. Changes in IIS/TOR signaling plays a key role in appendage development by regulating growth in the horn and mandible primordia. In contrast, changes in the IIS/TOR pathway produce minimal effects on the size of other adult structures, such as the male genitalia in fruit flies and dung beetles. The horn, mandible and genitalia illustrate that although all tissues are exposed to the same hormonal environment within the larval body, the extent to which insulin can induce growth is organ specific. In addition, the IIS/TOR pathway affects body size and shape by controlling production of metamorphic hormones important for regulating developmental timing, like the steroid molting hormone ecdysone and sesquiterpenoid hormone juvenile hormone. In this review, we discuss recent results from Drosophila and other insects that highlight mechanisms allowing tissues to differ in their sensitivity to IIS/TOR and the potential consequences of these differences on body size and shape. PMID:24133450

Spatial and body-size dependent response of marine pelagic communities to projected global climate change.

PubMed

Lefort, Stelly; Aumont, Olivier; Bopp, Laurent; Arsouze, Thomas; Gehlen, Marion; Maury, Olivier

2015-01-01

Temperature, oxygen, and food availability directly affect marine life. Climate models project a global warming of the ocean's surface (~+3 °C), a de-oxygenation of the ocean's interior (~-3%) and a decrease in total marine net primary production (~-8%) under the 'business as usual' climate change scenario (RCP8.5). We estimated the effects of these changes on biological communities using a coupled biogeochemical (PISCES)--ecosystems (APECOSM) model forced by the physical outputs of the last generation of the IPSL-CM Earth System Model. The APECOSM model is a size-structured bio-energetic model that simulates the 3D dynamical distributions of three interactive pelagic communities (epipelagic, mesopelagic, and migratory) under the effects of multiple environmental factors. The PISCES-APECOSM model ran from 1850 to 2100 under historical forcing followed by RCP8.5. Our RCP8.5 simulation highlights significant changes in the spatial distribution, biomass, and maximum body-size of the simulated pelagic communities. Biomass and maximum body-size increase at high latitude over the course of the century, reflecting the capacity of marine organisms to respond to new suitable environment. At low- and midlatitude, biomass and maximum body-size strongly decrease. In those regions, large organisms cannot maintain their high metabolic needs because of limited and declining food availability. This resource reduction enhances the competition and modifies the biomass distribution among and within the three communities: the proportion of small organisms increases in the three communities and the migrant community that initially comprised a higher proportion of small organisms is favored. The greater resilience of small body-size organisms resides in their capacity to fulfill their metabolic needs under reduced energy supply and is further favored by the release of predation pressure due to the decline of large organisms. These results suggest that small body-size organisms might be more resilient to climate change than large ones. © 2014 John Wiley & Sons Ltd.

Exploring the universal ecological responses to climate change in a univoltine butterfly.

PubMed

Fenberg, Phillip B; Self, Angela; Stewart, John R; Wilson, Rebecca J; Brooks, Stephen J

2016-05-01

Animals with distinct life stages are often exposed to different temperatures during each stage. Thus, how temperature affects these life stages should be considered for broadly understanding the ecological consequences of climate warming on such species. For example, temperature variation during particular life stages may affect respective change in body size, phenology and geographic range, which have been identified as the "universal" ecological responses to climate change. While each of these responses has been separately documented across a number of species, it is not known whether each response occurs together within a species. The influence of temperature during particular life stages may help explain each of these ecological responses to climate change. Our goal was to determine if monthly temperature variation during particular life stages of a butterfly species can predict respective changes in body size and phenology. We also refer to the literature to assess if temperature variability during the adult stage influences range change over time. Using historical museum collections paired with monthly temperature records, we show that changes in body size and phenology of the univoltine butterfly, Hesperia comma, are partly dependent upon temporal variation in summer temperatures during key stages of their life cycle. June temperatures, which are likely to affect growth rate of the final larval instar, are important for predicting adult body size (for males only; showing a positive relationship with temperature). July temperatures, which are likely to influence the pupal stage, are important for predicting the timing of adult emergence (showing a negative relationship with temperature). Previous studies show that August temperatures, which act on the adult stage, are linked to range change. Our study highlights the importance of considering temperature variation during each life stage over historic time-scales for understanding intraspecific response to climate change. Range edge studies of ectothermic species that have annual life cycles, long time-series occurrence data, and associated temperature records (ideally at monthly resolutions) could be useful model systems for intraspecific tests of the universal ecological responses to climate change and for exploring interactive effects. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

The influence of body size and net diversification rate on molecular evolution during the radiation of animal phyla

PubMed Central

Fontanillas, Eric; Welch, John J; Thomas, Jessica A; Bromham, Lindell

2007-01-01

Background Molecular clock dates, which place the origin of animal phyla deep in the Precambrian, have been used to reject the hypothesis of a rapid evolutionary radiation of animal phyla supported by the fossil record. One possible explanation of the discrepancy is the potential for fast substitution rates early in the metazoan radiation. However, concerted rate variation, occurring simultaneously in multiple lineages, cannot be detected by "clock tests", and so another way to explore such variation is to look for correlated changes between rates and other biological factors. Here we investigate two possible causes of fast early rates: change in average body size or diversification rate of deep metazoan lineages. Results For nine genes for phylogenetically independent comparisons between 50 metazoan phyla, orders, and classes, we find a significant correlation between average body size and rate of molecular evolution of mitochondrial genes. The data also indicate that diversification rate may have a positive effect on rates of mitochondrial molecular evolution. Conclusion If average body sizes were significantly smaller in the early history of the Metazoa, and if rates of diversification were much higher, then it is possible that mitochondrial genes have undergone a slow-down in evolutionary rate, which could affect date estimates made from these genes. PMID:17592650

Vertebral hemangiomas: their demographical characteristics, location along the spine and position within the vertebral body.

PubMed

Slon, Viviane; Stein, Dan; Cohen, Haim; Sella-Tunis, Tatiana; May, Hila; Hershkovitz, Israel

2015-10-01

Vertebral hemangiomas (VHs) are the most common form of benign tumors in the spine. The aim of this research was to study the prevalence of VHs in the human population, their distribution along the spine and their location in the vertebral body. The presence of VHs was assessed in full spine CT scans of 196 adults. Demographic data were gathered from medical records. VHs were present in 26.0% of the individuals studied, a rate significantly higher (χ2=43.338, p<0.001) than the prevalence reported in the literature (10.7%). Multiple VHs (≥2) appeared in 7.2% of the population studied. VHs prevalence is sex-independent, appearing in 28.6% of females and 23.5% of males (χ2=0.663, p=0.416); and age-dependent: the mean age of affected individuals (65.8 years) was significantly higher (p<0.001) than unaffected individuals (56.2 years). VH size was also age-dependent (p=0.023). No vertebra was significantly more prone to be affected by a hemangioma. T11 and T12 show the highest prevalence of VHs (3.57% of vertebrae affected). VHs were found in similar percentages in the anterior and posterior parts of the vertebral body (52.8 vs. 47.2%, respectively); and at its center and periphery (50.1 and 49.9%, respectively). VHs usually appeared at mid-height of the vertebral body or slightly higher. The reported prevalence of VHs is dependent on the demographic structure of the population studied, the size of the VHs and the method used to identify them. Overall, the phenomenon is more frequent than usually reported. VHs may appear at all vertebral levels and in all areas of the vertebral body.

Bodily Sensory Inputs and Anomalous Bodily Experiences in Complex Regional Pain Syndrome: Evaluation of the Potential Effects of Sound Feedback

PubMed Central

Tajadura-Jiménez, Ana; Cohen, Helen; Bianchi-Berthouze, Nadia

2017-01-01

Neuroscientific studies have shown that human's mental body representations are not fixed but are constantly updated through sensory feedback, including sound feedback. This suggests potential new therapeutic sensory approaches for patients experiencing body-perception disturbances (BPD). BPD can occur in association with chronic pain, for example in Complex Regional Pain Syndrome (CRPS). BPD often impacts on emotional, social, and motor functioning. Here we present the results from a proof-of-principle pilot study investigating the potential value of using sound feedback for altering BPD and its related emotional state and motor behavior in those with CRPS. We build on previous findings that real-time alteration of the sounds produced by walking can alter healthy people's perception of their own body size, while also resulting in more active gait patterns and a more positive emotional state. In the present study we quantified the emotional state, BPD, pain levels and gait of twelve people with CRPS Type 1, who were exposed to real-time alteration of their walking sounds. Results confirm previous reports of the complexity of the BPD linked to CRPS, as participants could be classified into four BPD subgroups according to how they mentally visualize their body. Further, results suggest that sound feedback may affect the perceived size of the CRPS affected limb and the pain experienced, but that the effects may differ according to the type of BPD. Sound feedback affected CRPS descriptors and other bodily feelings and emotions including feelings of emotional dominance, limb detachment, position awareness, attention and negative feelings toward the limb. Gait also varied with sound feedback, affecting the foot contact time with the ground in a way consistent with experienced changes in body weight. Although, findings from this small pilot study should be interpreted with caution, they suggest potential applications for regenerating BDP and its related bodily feelings in a clinical setting for patients with chronic pain and BPD. PMID:28798671

Resonance properties of the biological objects in the RF field

NASA Astrophysics Data System (ADS)

Cocherova, E.; Kupec, P.; Stofanik, V.

2011-12-01

Irradiation of people with electromagnetic fields emitted from miscellaneous devices working in the radio-frequency (RF) range may have influence, for example may affect brain processes. The question of health impact of RF electromagnetic fields on population is still not closed. This article is devoted to an investigation of resonance phenomena of RF field absorption in the models of whole human body and body parts (a head) of different size and shape. The values of specific absorption rate (SAR) are evaluated for models of the different shapes: spherical, cylindrical, realistic shape and for different size of the model, that represents the case of new-born, child and adult person. In the RF frequency region, absorption depends nonlinearly on frequency. Under certain conditions (E-polarization), absorption reaches maximum at frequency, that is called "resonance frequency". The whole body absorption and the resonance frequency depends on many further parameters, that are not comprehensively clarified. The simulation results showed the dependence of the whole-body average SAR and resonance frequency on the body dimensions, as well as the influence of the body shape.

Effects of Isometric Scaling on Vertical Jumping Performance

PubMed Central

Bobbert, Maarten F.

2013-01-01

Jump height, defined as vertical displacement in the airborne phase, depends on vertical takeoff velocity. For centuries, researchers have speculated on how jump height is affected by body size and many have adhered to what has come to be known as Borelli’s law, which states that jump height does not depend on body size per se. The underlying assumption is that the amount of work produced per kg body mass during the push-off is independent of size. However, if a big body is isometrically downscaled to a small body, the latter requires higher joint angular velocities to achieve a given takeoff velocity and work production will be more impaired by the force-velocity relationship of muscle. In the present study, the effects of pure isometric scaling on vertical jumping performance were investigated using a biologically realistic model of the human musculoskeletal system. The input of the model, muscle stimulation over time, was optimized using jump height as criterion. It was found that when the human model was miniaturized to the size of a mouse lemur, with a mass of about one-thousandth that of a human, jump height dropped from 40 cm to only 6 cm, mainly because of the force-velocity relationship. In reality, mouse lemurs achieve jump heights of about 33 cm. By implication, the unfavourable effects of the small body size of mouse lemurs on jumping performance must be counteracted by favourable effects of morphological and physiological adaptations. The same holds true for other small jumping animals. The simulations for the first time expose and explain the sheer magnitude of the isolated effects of isometric downscaling on jumping performance, to be counteracted by morphological and physiological adaptations. PMID:23936494

Sex, age, spleen size, and kidney fat of red deer relative to infection intensities of the lungworm Elaphostrongylus cervi

NASA Astrophysics Data System (ADS)

Vicente, J.; Pérez-Rodríguez, L.; Gortazar, C.

2007-07-01

We analyzed the relationships among spleen size, body condition (measured as kidney fat), and larval counts of the nematode Elaphostrongylus cervi in red deer ( Cervus elaphus). The aim was to investigate the interaction between host body condition and intensity of infection with parasites. As red deer are highly polygynous, we also tested whether these relationships varied with sex and age of the hosts. Kidney fat and spleen size were positively correlated in subadults (2-3 years old) and adults (>3 years old), but not in calves (<1 year old) or yearlings (1-2 years old). Spleen size was negatively associated with nematode load in subadult females and in adult males. These two age classes are potentially the most nutritionally stressed, as subadult hinds are still growing and often engaging in rearing their first calf, and adult stags were sampled just after the rut, which is recognized as a substantial energy drain in this age-sex class, as they compete to hold females during the mating season. Body condition related negatively to parasite count only in adult males. In the context of red deer life history, these findings suggest that spleen size is dependent on body condition and that it could be affected by variation in resource partitioning among immune defense, growth, and reproductive effort in red deer. For the first time in a wild mammal, the spleen mass is shown to be positively related to body condition and negatively related to parasite infection. We conclude that elucidating whether spleen mass reflects immune defense investment or a measure of general body condition should contribute to understanding topical issues in mammal ecology.

Body size and the division of niche space: food and predation differentially shape the distribution of Serengeti grazers.

PubMed

Hopcraft, J Grant C; Anderson, T Michael; Pérez-Vila, Saleta; Mayemba, Emilian; Olff, Han

2012-01-01

1. Theory predicts that small grazers are regulated by the digestive quality of grass, while large grazers extract sufficient nutrients from low-quality forage and are regulated by its abundance instead. In addition, predation potentially affects populations of small grazers more than large grazers, because predators have difficulty capturing and handling large prey. 2. We analyse the spatial distribution of five grazer species of different body size in relation to gradients of food availability and predation risk. Specifically, we investigate how the quality of grass, the abundance of grass biomass and the associated risks of predation affect the habitat use of small, intermediate and large savanna grazers at a landscape level. 3. Resource selection functions of five mammalian grazer species surveyed over a 21-year period in Serengeti are calculated using logistic regressions. Variables included in the analyses are grass nitrogen, rainfall, topographic wetness index, woody cover, drainage lines, landscape curvature, water and human habitation. Structural equation modelling (SEM) is used to aggregate predictor variables into 'composites' representing food quality, food abundance and predation risk. Subsequently, SEM is used to investigate species' habitat use, defined as their recurrence in 5 × 5 km cells across repeated censuses. 4. The distribution of small grazers is constrained by predation and food quality, whereas the distribution of large grazers is relatively unconstrained. The distribution of the largest grazer (African buffalo) is primarily associated with forage abundance but not predation risk, while the distributions of the smallest grazers (Thomson's gazelle and Grant's gazelle) are associated with high grass quality and negatively with the risk of predation. The distributions of intermediate sized grazers (Coke's hartebeest and topi) suggest they optimize access to grass biomass of sufficient quality in relatively predator-safe areas. 5. The results illustrate how top-down (vegetation-mediated predation risk) and bottom-up factors (biomass and nutrient content of vegetation) predictably contribute to the division of niche space for herbivores that vary in body size. Furthermore, diverse grazing assemblages are composed of herbivores of many body sizes (rather than similar body sizes), because these herbivores best exploit the resources of different habitat types. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

Life-history variation and allometry for sexual size dimorphism in Pacific salmon and trout

PubMed Central

Young, Kyle A.

2005-01-01

Allometry for sexual size dimorphism (SSD) is common in animals, but how different evolutionary processes interact to determine allometry remains unclear. Among related species SSD (male:female) typically increases with average body size, resulting in slopes of less than 1 when female size is regressed on male size: an allometric relationship formalized as ‘Rensch's rule’ . Empirical studies show that taxa with male-biased SSD are more likely to satisfy Rensch's rule and that a taxon's mean SSD is negatively correlated with allometric slope, implicating sexual selection on male size as an important mechanism promoting allometry for SSD. I use body length (and life-history) data from 628 (259) populations of seven species of anadromous Pacific salmon and trout (Oncorhynchus spp.) to show that in this genus life-history variation appears to regulate patterns of allometry both within and between species. Although all seven species have intraspecific allometric slopes of less than 1, contrary to expectation slope is unrelated to species' mean SSD, but is instead negatively correlated with two life-history variables: the species' mean marine age and variation in marine age. Second, because differences in marine age among species render SSD and body size uncorrelated, the interspecific slope is isometric. Together, these results provide an example of how evolutionary divergence in life history among related species can affect patterns of allometry for SSD across taxonomic scales. PMID:15695207

Observing Evolutionary Entropy in Relation to Body Size Over Time

NASA Astrophysics Data System (ADS)

Idgunji, S.; Zhang, H.; Payne, J.; Heim, N. A.

2015-12-01

The Second Law of Thermodynamics, according to Clausius, states that entropy will always increase in the universe, meaning systems will break down and become simple and chaotic. However, this is seemingly contradicted by the existence of living organisms, which can have highly complex and organized systems. Furthermore, there is a greater contradiction in the theory of evolution, which sees organisms growing larger and becoming more complex over time. Our research project revolved around whether organisms actually became more complex over time, and correlating these findings with the body size of these organisms. We analyzed the relationship between body size and cell types of five different marine phyla: arthropods, brachiopods, chordates, echinoderms, and mollusks. We attempted to find a relation between the biovolume of these different phyla and the number of specialized cell types that they had, which is a common measure of biocomplexity. In addition, we looked at the metabolic intensity, which is the mass-specific rate of energy processing applied to an organism's size, because it is also correlated to genetic complexity. Using R programming, we tested for correlations between these factors. After applying a Pearson correlation test, we discovered a generally positive correlation between the body sizes, number of cell types, and metabolic intensities of these phyla. However, one exception is that there is a negative correlation between the body size and metabolic intensity of echinoderms. Overall, we can see that marine organisms tend to evolve larger and more complex over time, and that is a very interesting find. Our discovery yielded many research questions and problems that we would like to solve, such as how the environment is thermodynamically affected by these organisms.

Implications of extreme sexual size dimorphism for thermoregulation in a freshwater turtle.

PubMed

Bulté, Grégory; Blouin-Demers, Gabriel

2010-02-01

Sexual size dimorphism (SSD) is a common phenomenon in animals. In many species females are substantially larger than males. Because body size plays a central role in modulating the body temperature (T (b)) of ectotherms, intersexual differences in body size may lead to important intersexual differences in thermoregulation. In addition, because SSD is realized by differences in growth rate and because growth rate is strongly temperature dependent in ectotherms, a conflict between male reproductive behaviour and thermoregulation may affect the expression of SSD. In this study, we investigated the thermal implications of SSD in a reptile exhibiting spectacular female-biased SSD: the northern map turtle (Graptemys geographica). Over three seasons, we collected >150,000 measurements of T (b) in free-ranging adult and juvenile northern map turtles using surgically implanted miniature temperature loggers. Northern map turtles exhibited seasonal patterns of thermoregulation typical of reptiles in northern latitudes, but we found that large adult females experienced a lower daily maximum T (b) and a narrower daily range of T (b) than adult males and small juvenile females. In addition, despite more time spent basking, large adult females were not able to thermoregulate as accurately as small turtles. Our findings strongly suggest that body size limits the ability to thermoregulate accurately in large females. By comparing thermoregulatory patterns between adult males and juvenile females of similar body size, we found no evidence that male reproductive behaviours are an impediment to thermoregulation. We also quantified the thermal significance of basking behaviour. We found, contrary to previous findings, that aerial basking allows northern map turtles to raise their T (b) substantially above water temperature, indicating that basking behaviour likely plays an important role in thermoregulation.

Current and previous spatial distributions of oilseed rape fields influence the abundance and the body size of a solitary wild bee, Andrena cineraria, in permanent grasslands.

PubMed

Van Reeth, Colin; Caro, Gaël; Bockstaller, Christian; Michel, Nadia

2018-01-01

Wild bees are essential pollinators whose survival partly depends on the capacity of their environment to offer a sufficient amount of nectar and pollen. Semi-natural habitats and mass-flowering crops such as oilseed rape provide abundant floristic resources for bees. The aim of this study was to evaluate the influences of the spatial distribution of semi-natural habitats and oilseed rape fields on the abundance and the mean body size of a solitary bee in grasslands. We focused on a generalist mining bee, Andrena cineraria, that forages and reproduces during oilseed rape flowering. In 21 permanent grasslands of Eastern France, we captured 1 287 individuals (1 205 males and 82 females) and measured the body size of male individuals. The flower density in grasslands was quantified during bee captures (2016) and the landscape surrounding grasslands was characterized during two consecutive years (2015 and 2016). The influence of oilseed rape was tested through its distribution in the landscape during both the current year of bee sampling and the previous year. Bee abundance was positively influenced by the flower density in grasslands and by the area covered by oilseed rape around grasslands in the previous year. The mean body size of A. cineraria was explained by the interaction between flower density in the grassland and the distance to the nearest oilseed rape field in the current year: the flower density positively influenced the mean body size only in grasslands distant from oilseed rape. A. cineraria abundance and body size distribution were not affected by the area of semi-natural habitats in the landscape. The spatial distribution of oilseed rape fields (during both the current and the previous year) as well as the local density of grassland flowers drive both bee abundance and the mean value of an intraspecific trait (body size) in permanent grasslands. Space-time variations of bee abundance and mean body size in grasslands may have important ecological implications on plant pollination and on interspecific interactions between pollinators. Specifically, a competition between bee species for nesting sites might occur in oilseed rape rich landscapes, thus raising important conservation issues for bee species that do not benefit from oilseed rape resources.

Down the Tubes: Vetting the Apparent Water-rich Parent Body being Accreted by the White Dwarf GD 16

NASA Astrophysics Data System (ADS)

Melis, Carl

2015-10-01

How water is distributed in a planetary system critically affects the formation, evolution, and habitability of its constituent rocky bodies. White dwarf stars provide a unique method to probe the prevalence of water-rich rocky bodies outside of our Solar system and where they preferentially reside in a planetary system. However, as evidenced by the case of GD 362, some parent bodies that at first glance might appear to be water-rich can actually be quite water-scarce. At this time there are only a small number of plausibly water-rich rocky bodies that are being actively accreted by their host white dwarf star. Given such a sample size it is crucial to characterize each one in sufficient detail to remove interlopers like GD 362 that might otherwise affect future statistical analyses. In this proposal we seek to vet GD 16, a water-rich candidate yet to be observed with HST-COS that is the brightest remaining such target in the UV.

Pollinator communities in strawberry crops - variation at multiple spatial scales.

PubMed

Ahrenfeldt, E J; Klatt, B K; Arildsen, J; Trandem, N; Andersson, G K S; Tscharntke, T; Smith, H G; Sigsgaard, L

2015-08-01

Predicting potential pollination services of wild bees in crops requires knowledge of their spatial distribution within fields. Field margins can serve as nesting and foraging habitats for wild bees and can be a source of pollinators. Regional differences in pollinator community composition may affect this spill-over of bees. We studied how regional and local differences affect the spatial distribution of wild bee species richness, activity-density and body size in crop fields. We sampled bees both from the field centre and at two different types of semi-natural field margins, grass strips and hedges, in 12 strawberry fields. The fields were distributed over four regions in Northern Europe, representing an almost 1100 km long north-south gradient. Even over this gradient, daytime temperatures during sampling did not differ significantly between regions and did therefore probably not impact bee activity. Bee species richness was higher in field margins compared with field centres independent of field size. However, there was no difference between centre and margin in body-size or activity-density. In contrast, bee activity-density increased towards the southern regions, whereas the mean body size increased towards the north. In conclusion, our study revealed a general pattern across European regions of bee diversity, but not activity-density, declining towards the field interior which suggests that the benefits of functional diversity of pollinators may be difficult to achieve through spill-over effects from margins to crop. We also identified dissimilar regional patterns in bee diversity and activity-density, which should be taken into account in conservation management.

Endocarp thickness affects seed removal speed by small rodents in a warm-temperate broad-leafed deciduous forest, China

NASA Astrophysics Data System (ADS)

Zhang, Hongmao; Zhang, Zhibin

2008-11-01

Seed traits are important factors affecting seed predation by rodents and thereby the success of recruitment. Seeds of many tree species have hard hulls. These are thought to confer mechanical protection, but the effect of endocarp thickness on seed predation by rodents has not been well investigated. Wild apricot ( Prunus armeniaca), wild peach ( Amygdalus davidiana), cultivated walnut ( Juglans regia), wild walnut ( Juglans mandshurica Maxim) and Liaodong oak ( Quercus liaotungensis) are very common tree species in northwestern Beijing city, China. Their seeds vary greatly in size, endocarp thickness, caloric value and tannin content. This paper aims to study the effects of seed traits on seed removal speed of these five tree species by small rodents in a temperate deciduous forest, with emphasis on the effect of endocarp thickness. The results indicated that speed of removal of seeds released at stations in the field decreased significantly with increasing endocarp thickness. We found no significant correlations between seed removal speed and other seed traits such as seed size, caloric value and tannin content. In seed selection experiments in small cages, Père David's rock squirrel ( Sciurotamias davidianus), a large-bodied, strong-jawed rodent, selected all of the five seed species, and the selection order among the five seed species was determined by endocarp thickness and the ratio of endocarp mass/seed mass. In contrast, the Korean field mouse ( Apodemus peninsulae) and Chinese white-bellied rat ( Niviventer confucianus), with relatively small bodies and weak jaws, preferred to select small seeds like acorns of Q. liaotungensis and seeds of P. armeniaca, indicating that rodent body size is also an important factor affecting food selection based on seed size. These results suggest endocarp thickness significantly reduces seed removal speed by rodents and then negatively affects dispersal fitness of seeds before seed removal of tree species in the study region. However, effect of endocarp thickness on final dispersal fitness needs further investigation because it may increase seed caching and survival after seed removal.

Climate warming is associated with smaller body size and shorter lifespans in moose near their southern range limit.

PubMed

Hoy, Sarah R; Peterson, Rolf O; Vucetich, John A

2018-06-01

Despite the importance of body size for individual fitness, population dynamics and community dynamics, the influence of climate change on growth and body size is inadequately understood, particularly for long-lived vertebrates. Although temporal trends in body size have been documented, it remains unclear whether these changes represent the adverse impact of climate change (environmental stress constraining phenotypes) or its mitigation (via phenotypic plasticity or evolution). Concerns have also been raised about whether climate change is indeed the causal agent of these phenotypic shifts, given the length of time-series analysed and that studies often do not evaluate - and thereby sufficiently rule out - other potential causes. Here, we evaluate evidence for climate-related changes in adult body size (indexed by skull size) over a 4-decade period for a population of moose (Alces alces) near the southern limit of their range whilst also considering changes in density, predation, and human activities. In particular, we document: (i) a trend of increasing winter temperatures and concurrent decline in skull size (decline of 19% for males and 13% for females) and (ii) evidence of a negative relationship between skull size and winter temperatures during the first year of life. These patterns could be plausibly interpreted as an adaptive phenotypic response to climate warming given that latitudinal/temperature clines are often accepted as evidence of adaptation to local climate. However, we also observed: (iii) that moose with smaller skulls had shorter lifespans, (iv) a reduction in lifespan over the 4-decade study period, and (v) a negative relationship between lifespan and winter temperatures during the first year of life. Those observations indicate that this phenotypic change is not an adaptive response to climate change. However, this decline in lifespan was not accompanied by an obvious change in population dynamics, suggesting that climate change may affect population dynamics and life-histories differently. © 2017 John Wiley & Sons Ltd.

Gay and Lesbian Parents

MedlinePlus

... Life Listen Español Text Size Email Print Share Gay and Lesbian Parents Page Content Article Body I am gay. Should I worry how this will affect my children? Millions of children have one or more gay and/or lesbian parents. For some children, having ...

Influence of breeding habitat on bear predation and age at maturity and sexual dimorphism of sockeye salmon populations

USGS Publications Warehouse

Quinn, Thomas P.; Wetzel, Lisa A.; Bishop, Susan; Overberg, Kristi; Rogers, Donald E.

2001-01-01

Age structure and morphology differ among Pacific salmon (Oncorhynchus spp.) populations. Sexual selection and reproductive capacity (fecundity and egg size) generally favor large (old), deep-bodied fish. We hypothesized that natural selection from physical access to spawning grounds and size-biased predation by bears, Ursus spp., opposes such large, deep-bodied salmon. Accordingly, size and shape of salmon should vary predictably among spawning habitats. We tested this hypothesis by measuring the age composition and body depth of sockeye salmon, Oncorhynchus nerka, and the intensity of predation in a range of breeding habitats in southwestern Alaska. Stream width was positively correlated with age at maturity and negatively correlated with predation level. However, salmon spawning on lake beaches were not consistently old, indicating that different factors affect age in riverine- and beach-spawning populations. Body depths of male and female salmon were positively correlated with water depth across all sites, as predicted. However, the mouths of some streams were so shallow that they might select against large or deep-bodied salmon, even in the absence of bear predation. Taken together, the results indicated that habitat has direct and indirect effects (via predation) on life history and morphology of mature salmon.

Individual Factors Affecting Self-esteem, and Relationships Among Self-esteem, Body Mass Index, and Body Image in Patients With Schizophrenia.

PubMed

Oh, EunJung; Song, EunJu; Shin, JungEun

2017-12-01

The purposes of this study were to identify correlations between body mass index, body image, and self-esteem in patients with schizophrenia and to analyse the specific factors affecting self-esteem. This study had a descriptive design, utilising a cross-sectional survey. Participants were patients with schizophrenia who were admitted to a mental health facility in South Korea. A total of 180 questionnaires were distributed, and an appropriate total sample size of 167 valid questionnaires was analysed. Self-esteem was significantly correlated with body image, the subscale of appearance orientation, and body areas satisfaction. However, body mass index exhibited no significant correlation with any variable. The variables found to have a significant explanatory power of 21.4% were appearance orientation and body areas satisfaction. The explanatory power of all factors was 33.6%. The self-esteem of patients with schizophrenia was influenced by body mass index and body image. The positive symptoms of schizophrenia can be controlled by medication, whereas negative symptoms can be improved through education and nursing care with medication. Thus, psychiatric nurses should develop education and care programs that contribute to the positive body image and self-esteem of patients with schizophrenia. Copyright © 2017 Elsevier Inc. All rights reserved.

Additive genetic variation in the craniofacial skeleton of baboons (genus Papio) and its relationship to body and cranial size.

PubMed

Joganic, Jessica L; Willmore, Katherine E; Richtsmeier, Joan T; Weiss, Kenneth M; Mahaney, Michael C; Rogers, Jeffrey; Cheverud, James M

2018-02-01

Determining the genetic architecture of quantitative traits and genetic correlations among them is important for understanding morphological evolution patterns. We address two questions regarding papionin evolution: (1) what effect do body and cranial size, age, and sex have on phenotypic (V P ) and additive genetic (V A ) variation in baboon crania, and (2) how might additive genetic correlations between craniofacial traits and body mass affect morphological evolution? We use a large captive pedigreed baboon sample to estimate quantitative genetic parameters for craniofacial dimensions (EIDs). Our models include nested combinations of the covariates listed above. We also simulate the correlated response of a given EID due to selection on body mass alone. Covariates account for 1.2-91% of craniofacial V P . EID V A decreases across models as more covariates are included. The median genetic correlation estimate between each EID and body mass is 0.33. Analysis of the multivariate response to selection reveals that observed patterns of craniofacial variation in extant baboons cannot be attributed solely to correlated response to selection on body mass, particularly in males. Because a relatively large proportion of EID V A is shared with body mass variation, different methods of correcting for allometry by statistically controlling for size can alter residual V P patterns. This may conflate direct selection effects on craniofacial variation with those resulting from a correlated response to body mass selection. This shared genetic variation may partially explain how selection for increased body mass in two different papionin lineages produced remarkably similar craniofacial phenotypes. © 2017 Wiley Periodicals, Inc.

Effects of season, temperature, and body mass on the standard metabolic rate of tegu lizards (Tupinambis merianae).

PubMed

Toledo, Luís F; Brito, Simone P; Milsom, William K; Abe, Augusto S; Andrade, Denis V

2008-01-01

Abstract This study examined how the standard metabolic rate of tegu lizards, a species that undergoes large ontogenetic changes in body weight with associated changes in life-history traits, is affected by changes in body mass, body temperature, season, and life-history traits. We measured rates of oxygen consumption (Vo(2)) in 90 individuals ranging in body mass from 10.4 g to 3.75 kg at three experimental temperatures (17 degrees , 25 degrees , and 30 degrees C) over the four seasons. We found that standard metabolic rate scaled to the power of 0.84 of body mass at all experimental temperatures in all seasons and that thermal sensitivity of metabolism was relatively low (Q(10) approximately 2.0-2.5) over the range from 17 degrees to 30 degrees C regardless of body size or season. Metabolic rates did vary seasonally, being higher in spring and summer than in autumn and winter at the same temperatures, and this was true regardless of animal size. Finally, in this study, the changes in life-history traits that occurred ontogenetically were not accompanied by significant changes in metabolic rate.

SECULAR CHANGES IN BIRTH WEIGHTS AND WOMEN'S BODY SIZE IN KRAKÓW AND POZNAŃ (POLAND) DURING THE LAST CENTURY.

PubMed

Kryst, Łukasz; Bilińska, Inez

2017-05-01

Changing socioeconomic conditions over the last century have left their mark on neonatal size and final body size of individuals born in those days. The main aim of this study was to investigate how the historical, political and economic changes occurring from the late 19th century to the 2000s have affected the birth weight of newborns. Additionally, changes in weight and body height in the case of young women (potential mothers) were analysed. Data were from two cities in Poland (Kraków and Poznań) covering 15,884 newborns and 3612 women aged 18 years, derived from 1900 to 2010. Despite short-term fluctuations, the results showed significant increasing trends in all studied features. Changes in birth weight were similar in both cities: in Kraków it increased by 184 g (males) and 206 g (females), and in Poznań by 216 g (males) and 120 g (females). Changes in women's body size were also significant, but the level was different depending on place of residence. In the last century, women's body height increased by 8.2 cm in Kraków and by 10.2 cm in Poznań, and their body weight increased by 1 kg and 5 kg respectively. The considered period covered the years of socioeconomic change that occurred as a result of the political system transformation. Crises, periods of prosperity and other factors that determine standard of living and health care have influenced the development of the Polish population's physical features.

The evolutionary legacy of size-selective harvesting extends from genes to populations

PubMed Central

Uusi-Heikkilä, Silva; Whiteley, Andrew R; Kuparinen, Anna; Matsumura, Shuichi; Venturelli, Paul A; Wolter, Christian; Slate, Jon; Primmer, Craig R; Meinelt, Thomas; Killen, Shaun S; Bierbach, David; Polverino, Giovanni; Ludwig, Arne; Arlinghaus, Robert

2015-01-01

Size-selective harvesting is assumed to alter life histories of exploited fish populations, thereby negatively affecting population productivity, recovery, and yield. However, demonstrating that fisheries-induced phenotypic changes in the wild are at least partly genetically determined has proved notoriously difficult. Moreover, the population-level consequences of fisheries-induced evolution are still being controversially discussed. Using an experimental approach, we found that five generations of size-selective harvesting altered the life histories and behavior, but not the metabolic rate, of wild-origin zebrafish (Danio rerio). Fish adapted to high positively size selective fishing pressure invested more in reproduction, reached a smaller adult body size, and were less explorative and bold. Phenotypic changes seemed subtle but were accompanied by genetic changes in functional loci. Thus, our results provided unambiguous evidence for rapid, harvest-induced phenotypic and evolutionary change when harvesting is intensive and size selective. According to a life-history model, the observed life-history changes elevated population growth rate in harvested conditions, but slowed population recovery under a simulated moratorium. Hence, the evolutionary legacy of size-selective harvesting includes populations that are productive under exploited conditions, but selectively disadvantaged to cope with natural selection pressures that often favor large body size. PMID:26136825

Age-related effects of body mass on fertility and litter size in roe deer.

PubMed

Flajšman, Katarina; Jerina, Klemen; Pokorny, Boštjan

2017-01-01

We analysed effects of females' body mass and age on reproductive capacity of European roe deer (Capreolus capreolus) in a large sample set of 1312 females (305 yearlings and 1007 adults), hunted throughout Slovenia, central Europe, in the period 2013-2015. Body mass positively affected probability of ovulation and potential litter size (number of corpora lutea), although its effect was more pronounced in yearlings than in adults. Between age groups, we found clear differences in responses of both reproductive parameters to body mass which influences primarily reproductive performance of younger, and in particular, lighter individuals: at the same body mass yearlings would at average have smaller litters than adults, and at lower body mass also young to middle-aged adults would have smaller litters than old ones. In addition, while yearlings have to reach a critical threshold body mass to attain reproductive maturity, adult females are fertile (produce ova) even at low body mass. However, at higher body mass also younger individuals shift their efforts into the reproduction, and after reaching an age-specific threshold the body mass does not have any further effects on the reproductive output of roe deer females. Increased reproductive capacity at more advanced age, combined with declining body mass suggests that old does allocate more of their resources in reproduction than in body condition.

Age-related effects of body mass on fertility and litter size in roe deer

PubMed Central

Jerina, Klemen; Pokorny, Boštjan

2017-01-01

We analysed effects of females’ body mass and age on reproductive capacity of European roe deer (Capreolus capreolus) in a large sample set of 1312 females (305 yearlings and 1007 adults), hunted throughout Slovenia, central Europe, in the period 2013–2015. Body mass positively affected probability of ovulation and potential litter size (number of corpora lutea), although its effect was more pronounced in yearlings than in adults. Between age groups, we found clear differences in responses of both reproductive parameters to body mass which influences primarily reproductive performance of younger, and in particular, lighter individuals: at the same body mass yearlings would at average have smaller litters than adults, and at lower body mass also young to middle-aged adults would have smaller litters than old ones. In addition, while yearlings have to reach a critical threshold body mass to attain reproductive maturity, adult females are fertile (produce ova) even at low body mass. However, at higher body mass also younger individuals shift their efforts into the reproduction, and after reaching an age-specific threshold the body mass does not have any further effects on the reproductive output of roe deer females. Increased reproductive capacity at more advanced age, combined with declining body mass suggests that old does allocate more of their resources in reproduction than in body condition. PMID:28403161

Effect of planform and body on supersonic aerodynamics of multibody configurations

NASA Technical Reports Server (NTRS)

Mcmillin, S. Naomi; Bauer, Steven X. S.; Howell, Dorothy T.

1992-01-01

An experimental and theoretical investigation of the effect of the wing planform and bodies on the supersonic aerodynamics of a low-fineness-ratio, multibody configuration has been conducted in the Langley Unitary Plan Wind Tunnel at Mach numbers of 1.60, 1.80, 2.00, and 2.16. Force and moment data, flow-visualization data, and surface-pressure data were obtained on eight low-fineness-ratio, twin-body configurations. These configurations varied in inboard wing planform shape, outboard wing planform shape, outboard wing planform size, and presence of the bodies. The force and moment data showed that increasing the ratio of outboard wing area to total wing area or increasing the leading-edge sweep of the inboard wing influenced the aerodynamic characteristics. The flow-visualization data showed a complex flow-field system of shocks, shock-induced separation, and body vortex systems occurring between the side bodies. This flow field was substantially affected by the inboard wing planform shape but minimally affected by the outboard wing planform shape. The flow-visualization and surface-pressure data showed that flow over the outboard wing developed as expected with changes in angle of attack and Mach number and was affected by the leading-edge sweep of the inboard wing and the presence of the bodies. Evaluation of the linear-theory prediction methods revealed their general inability to consistently predict the characteristics of these multibody configurations.

Embodiment of social roles and thinness as a form of capital: A qualitative approach towards understanding female obesity disparities in Chile.

PubMed

Robinovich, Jossiana; Ossa, Ximena; Baeza, Bernardita; Krumeich, Anja; van der Borne, Bart

2018-03-01

Obesity in Chile disproportionately affects women of low socioeconomic status (SES). Research has shown that ideals of body size and differences in perceived social pressure for being slim across socioeconomic strata contribute to the social stratification of body size among women in modern societies. Thinness is most valued by high SES women, following western standards of ideal body size. Aiming to understand the link between ideals of body size and SES, this qualitative study explored how 36 Chilean women construct their bodily ideals according to their social position. A purposive sample of women with different profiles with regard to educational attainment, nutritional status and body size (dis)satisfaction was defined, aiming to cover a diverse spectrum of bodily perceptions. Data were collected through semi-structured interviews and approached through a thematic and narrative analysis. Drawing on Bourdieu's concepts of habitus, field, capital and embodiment of the social context, this study explains how ideals of body size and appearance are strongly linked to class-dependent gender roles and social roles. The existing gender and class inequalities in the Chilean social structure have been literally embodied by these women through a 'gendered class habitus'. Compliance with the thin ideal confers women different degrees of power according to their social position in different fields, such as in marriage and on the labour market, which turns thinness into an embodied form of capital. The societal dynamic behind obesity rates cannot be disregarded when approaching possible solutions. Promoting obesity-related lifestyle modification at an individual level might appear an over-simplistic and individualistic approach to a complex social issue. Context-oriented interventions that take cultural constructions of gender and social class into account might yield better results in the long term, while advocating for a more equitable society and social justice as a public health concern. Copyright © 2018 Elsevier Ltd. All rights reserved.

Adaptive evolution of body size subject to indirect effect in trophic cascade system.

PubMed

Wang, Xin; Fan, Meng; Hao, Lina

2017-09-01

Trophic cascades represent a classic example of indirect effect and are wide-spread in nature. Their ecological impact are well established, but the evolutionary consequences have received even less theoretical attention. We theoretically and numerically investigate the trait (i.e., body size of consumer) evolution in response to indirect effect in a trophic cascade system. By applying the quantitative trait evolutionary theory and the adaptive dynamic theory, we formulate and explore two different types of eco-evolutionary resource-consumer-predator trophic cascade model. First, an eco-evolutionary model incorporating the rapid evolution is formulated to investigate the effect of rapid evolution of the consumer's body size, and to explore the impact of density-mediate indirect effect on the population dynamics and trait dynamics. Next, by employing the adaptive dynamic theory, a long-term evolutionary model of consumer body size is formulated to evaluate the effect of long-term evolution on the population dynamics and the effect of trait-mediate indirect effect. Those models admit rich dynamics that has not been observed yet in empirical studies. It is found that, both in the trait-mediated and density-mediated system, the body size of consumer in predator-consumer-resource interaction (indirect effect) evolves smaller than that in consumer-resource and predator-consumer interaction (direct effect). Moreover, in the density-mediated system, we found that the evolution of consumer body size contributes to avoiding consumer extinction (i.e., evolutionary rescue). The trait-mediate and density-mediate effects may produce opposite evolutionary response. This study suggests that the trophic cascade indirect effect affects consumer evolution, highlights a more comprehensive mechanistic understanding of the intricate interplay between ecological and evolutionary force. The modeling approaches provide avenue for study on indirect effects from an evolutionary perspective. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of experimentally elevated traffic noise on nestling white-crowned sparrow stress physiology, immune function and life history.

PubMed

Crino, Ondi L; Johnson, Erin E; Blickley, Jessica L; Patricelli, Gail L; Breuner, Creagh W

2013-06-01

Roads have been associated with behavioral and physiological changes in wildlife. In birds, roads decrease reproductive success and biodiversity and increase physiological stress. Although the consequences of roads on individuals and communities have been well described, the mechanisms through which roads affect birds remain largely unexplored. Here, we examine one mechanism through which roads could affect birds: traffic noise. We exposed nestling mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) to experimentally elevated traffic noise for 5 days during the nestling period. Following exposure to traffic noise we measured nestling stress physiology, immune function, body size, condition and survival. Based on prior studies, we expected the traffic noise treatment to result in elevated stress hormones (glucocorticoids), and declines in immune function, body size, condition and survival. Surprisingly, nestlings exposed to traffic noise had lower glucocorticoid levels and improved condition relative to control nests. These results indicate that traffic noise does affect physiology and development in white-crowned sparrows, but not at all as predicted. Therefore, when evaluating the mechanisms through which roads affect avian populations, other factors (e.g. edge effects, pollution and mechanical vibration) may be more important than traffic noise in explaining elevated nestling stress responses in this species.

Rates of molecular evolution in tree ferns are associated with body size, environmental temperature, and biological productivity.

PubMed

Barrera-Redondo, Josué; Ramírez-Barahona, Santiago; Eguiarte, Luis E

2018-05-01

Variation in rates of molecular evolution (heterotachy) is a common phenomenon among plants. Although multiple theoretical models have been proposed, fundamental questions remain regarding the combined effects of ecological and morphological traits on rate heterogeneity. Here, we used tree ferns to explore the correlation between rates of molecular evolution in chloroplast DNA sequences and several morphological and environmental factors within a Bayesian framework. We revealed direct and indirect effects of body size, biological productivity, and temperature on substitution rates, where smaller tree ferns living in warmer and less productive environments tend to have faster rates of molecular evolution. In addition, we found that variation in the ratio of nonsynonymous to synonymous substitution rates (dN/dS) in the chloroplast rbcL gene was significantly correlated with ecological and morphological variables. Heterotachy in tree ferns may be influenced by effective population size associated with variation in body size and productivity. Macroevolutionary hypotheses should go beyond explaining heterotachy in terms of mutation rates and instead, should integrate population-level factors to better understand the processes affecting the tempo of evolution at the molecular level. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Ecological consequences of body size decline in harvested fish species: positive feedback loops in trophic interactions amplify human impact.

PubMed

Audzijonyte, Asta; Kuparinen, Anna; Gorton, Rebecca; Fulton, Elizabeth A

2013-04-23

Humans are changing marine ecosystems worldwide, both directly through fishing and indirectly through climate change. One of the little explored outcomes of human-induced change involves the decreasing body sizes of fishes. We use a marine ecosystem model to explore how a slow (less than 0.1% per year) decrease in the length of five harvested species could affect species interactions, biomasses and yields. We find that even small decreases in fish sizes are amplified by positive feedback loops in the ecosystem and can lead to major changes in natural mortality. For some species, a total of 4 per cent decrease in length-at-age over 50 years resulted in 50 per cent increase in predation mortality. However, the magnitude and direction in predation mortality changes differed among species and one shrinking species even experienced reduced predation pressure. Nevertheless, 50 years of gradual decrease in body size resulted in 1-35% decrease in biomasses and catches of all shrinking species. Therefore, fisheries management practices that ignore contemporary life-history changes are likely to overestimate long-term yields and can lead to overfishing.

Evolution of Sexual Dimorphism in the Digit Ratio 2D:4D - Relationships with Body Size and Microhabitat Use in Iguanian Lizards

PubMed Central

Gomes, Camilla M.; Kohlsdorf, Tiana

2011-01-01

The ratio between lengths of digit II and IV (digit ratio 2D:4D) is a morphological feature that likely affects tetrapod locomotor performances in different microhabitats. Modifications of this trait may be triggered by changes in steroids concentrations during embryo development, which might reflect direct selection acting on digit ratio or be solely a consequence of hormonal differences related for example to body size. Here we apply both conventional and phylogenetic analyses on morphological data from 25 lizard species of 3 families of Iguania (Iguanidae, Polychrotidae, and Tropiduridae), in order to verify whether selective pressures related to locomotion in different microhabitats could override the prenatal developmental cues imposed on the digit ratio 2D:4D by differences in body size between males and females. Data suggest that this trait evolved in association with ecological divergence in the species studied, despite the clear effect of body size on the digit ratio 2D:4D. The ecological associations of size-corrected digit ratios were restricted to one sex, and females of species that often use perches exhibited small digit ratios in the front limbs, which translated into larger sexual dimorphism indexes of arboreal species. The results, together with the subsequent discussion, provide outlines for further investigation about possible developmental mechanisms related to the evolution of adaptive changes in digit lengths that may have occurred during the evolution of ecological divergence in squamates. PMID:22162772

40 CFR 6.207 - Environmental impact statements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... federal actions significantly affecting the quality of the human environment, including actions for which... treated effluent from a new or modified existing facility into a body of water and the discharge is likely... size and location of new and existing facilities, land requirements, operation and maintenance...

40 CFR 6.207 - Environmental impact statements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... federal actions significantly affecting the quality of the human environment, including actions for which... treated effluent from a new or modified existing facility into a body of water and the discharge is likely... size and location of new and existing facilities, land requirements, operation and maintenance...

40 CFR 6.207 - Environmental impact statements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... federal actions significantly affecting the quality of the human environment, including actions for which... treated effluent from a new or modified existing facility into a body of water and the discharge is likely... size and location of new and existing facilities, land requirements, operation and maintenance...

Decoupled responses of soil bacteria and their invertebrate consumer to warming, but not freeze-thaw cycles, in the Antarctic Dry Valleys.

PubMed

Knox, Matthew A; Andriuzzi, Walter S; Buelow, Heather N; Takacs-Vesbach, Cristina; Adams, Byron J; Wall, Diana H

2017-10-01

Altered temperature profiles resulting in increased warming and freeze-thaw cycle (FTC) frequency pose great ecological challenges to organisms in alpine and polar ecosystems. We performed a laboratory microcosm experiment to investigate how temperature variability affects soil bacterial cell numbers, and abundance and traits of soil microfauna (the microbivorous nematode Scottnema lindsayae) from McMurdo Dry Valleys, Antarctica. FTCs and constant freezing shifted nematode body size distribution towards large individuals, driven by higher mortality among smaller individuals. FTCs reduced both bacterial and nematode abundance, but bacterial cell numbers also declined under warming, demonstrating decoupled consumer-prey responses. We predict that higher occurrence of FTCs in cold ecosystems will select for large body size within soil microinvertebrates and overall reduce their abundance. In contrast, warm temperatures without FTCs could lead to divergent responses in soil bacteria and their microinvertebrate consumers, potentially affecting energy and nutrient transfer rates in soil food webs of cold ecosystems. © 2017 John Wiley & Sons Ltd/CNRS.

Thinking big: the effect of sexually objectifying music videos on bodily self-perception in young women.

PubMed

Mischner, Isabelle H S; van Schie, Hein T; Wigboldus, Daniël H J; van Baaren, Rick B; Engels, Rutger C M E

2013-01-01

The present study investigated the effect of sexually objectifying music video exposure on young women's implicit bodily self-perception and the moderating role of self-esteem. Fifty-six college women of normal weight were either exposed to three sexually objectifying music videos or three neutral music videos. Perceived and ideal body size were measured both before and after video exposure, using horizontally stretched and compressed photographs of the participant's own body in swimming garment. As expected, only women low (but not high) in self-esteem were negatively affected by the sexually objectifying content of the music videos: they perceived themselves as bigger and showed an increased discrepancy between their perceived and ideal body size after video exposure. The neutral music videos did not influence women's bodily self-perceptions. These findings suggest that body image is a flexible construct, and that high self-esteem can protect women against the adverse effects of sexually objectifying media. Copyright © 2012 Elsevier Ltd. All rights reserved.

The influence of life history trade-offs and the size of the incubation gravels on egg size variation in sockeye salmon Onchorhynchus nerka

USGS Publications Warehouse

Quinn, Thomas P.; Hendry , Andrew P.; Wetzel, Lisa A.

1995-01-01

Egg size is a critical life history trait, reflecting female investment and affecting off- spring fitness. We investigated several factors which may influence variation in egg weight for sockeye salmon (Oncorhynchus nerka). Comparisons were based on col- lections from 18 Alaskan populations, among which adult migration distance and ju- venile rearing habitat were similar but the size composition of incubation gravels was different. Among populations, most of the variation in egg weight could be explained by a positive correlation with different measures of the size composition of incubation gravels (Pearson's r = 0.45-0.91). In contrast, egg weight was poorly correlated with female body length and with female snout length, a morphological feature used during intra-sexual competition. Within each of the Alaskan populations, however, egg weight and snout length were positively correlated with female body length and hence with each other. A positive association between snout length and egg weight was still evident even after the effects of covariance with body size were removed using resid- uals analysis: for all of the fish pooled and within 6 of the 16 populations. A signifi- cant relationship was not detected in the other populations but the trend was neverthe- less positive in 8 of the other 10. Examination of reproductive traits (gonad weight, egg weight, egg number, snout length and hump size) within another population iden- tified a trade-off between egg weight and egg number for females of a given body length. In contrast, positive correlations between reproductive traits were more com- mon, suggesting that energy-rich individuals produce large eggs and large secondary sexual characteristics rather than sacrificing one for the other.

Sensory cortex limits cortical maps and drives top-down plasticity in thalamocortical circuits

PubMed Central

Zembrzycki, Andreas; Chou, Shen-Ju; Ashery-Padan, Ruth; Stoykova, Anastassia; O’Leary, Dennis D.M.

2013-01-01

Summary Primary somatosensory cortex (S1) contains a complete body map that mirrors subcortical maps developed by peripheral sensory input projecting to sensory hindbrain, thalamus, then S1. Peripheral changes during development alter these maps through ‘bottom-up’ plasticity. Unknown is how S1 size influences map organization and if an altered S1 map feedbacks to affect subcortical maps. We show in mice that S1 is significantly reduced by cortex-specific deletion of Pax6, resulting in a reduced body map and loss of body representations by exclusion of later-differentiating sensory thalamocortical input. An initially normal sensory thalamus was re-patterned to match the aberrant S1 map by apoptotic deletion of thalamic neurons representing body parts with axons excluded from S1. Deleted representations were rescued by altering competition between thalamocortical axons by sensory deprivation or increasing S1. Thus, S1 size determined resolution and completeness of body maps and engaged ‘top-down’ plasticity that re-patterned sensory thalamus to match S1. PMID:23831966

Alice in Wonderland Syndrome: A Historical and Medical Review.

PubMed

Farooq, Osman; Fine, Edward J

2017-12-01

Alice in Wonderland syndrome is a disorienting neurological condition that affects human perception to the senses of vision, hearing, touch, sensation, and the phenomenon of time. Individuals affected with Alice in Wonderland syndrome can experience alterations in their perception of the size of objects or their own body parts, known as metamorphopsias. It is known to occur in conditions including migraine, epilepsy, and certain intoxicants and infectious diseases. The name refers to Lewis Carrol's well-known children's book Alice's Adventures in Wonderland, in which the title character experiences alterations of sensation in which she felt that her body had grown too tall or too small, or parts of her body were changing shape, size, or relationship to the rest of her body. The syndrome was described in 1952 by Caro Lippman, and given its name in 1955 by John Todd. The metamorphopsias characteristic of this condition are also sometimes referred to as Lilliputian hallucinations, a reference to the fictional island of Lilliput in the novel Gulliver's Travels, written by Jonathan Swift in 1726. As such, many literary and medical publications have roots in the description of this syndrome. The purpose of this review is to summarize the literary and historical significance of Alice in Wonderland syndrome, as well as to provide the reader with a medical overview of the condition. Copyright © 2017 Elsevier Inc. All rights reserved.

Correlates of elemental-isotopic composition of stream fishes: the importance of land-use, species identity and body size.

PubMed

Montaña, C G; Schalk, C M

2018-04-01

The isotopic (δ 13 C and δ 15 N) and stoichiometric (C:N:P) compositions of four fish species (Family Centrarchidae: Lepomis auritus, Lepomis cyanellus; Family Cyprinidae: Nocomis leptocephalus, Semotilus atromaculatus) were examined across four North Carolina Piedmont streams arrayed along an urbanization gradient. Both isotopic and stoichiometric composition of fishes appeared to track changes occurring in basal resource availability. Values of δ 13 C of basal resources and consumers were more enriched at the most urbanized streams. Similarly, basal resources and consumers were δ 15 N-enriched at more urbanized streams. Basal resource stoichiometry varied across streams, with periphyton being the most variable. Primary consumers stoichiometry also differed across streams. Intraspecific variation in fish stoichiometry correlated with the degree of urbanization, as the two cyprinids had higher N content and L. cyanellus had higher P content in more urbanized streams, probably due to enrichment of basal resources. Intrinsic factors, specifically species identity and body size also affected stoichiometric variation. Phosphorus (P) content increased significantly with body size in centrarchids, but not in cyprinids. These results suggest that although species identity and body size are important predictors of elemental stoichiometry, the complex nature of altered urban streams may yield imbalances in the elemental composition of consumers via their food resources. © 2018 The Fisheries Society of the British Isles.

Factors affecting retention of early pregnancy in dairy cattle.

PubMed

Starbuck, Melanie J; Dailey, Robert A; Inskeep, E Keith

2004-08-01

Potential factors affecting retention of pregnancy during weeks 5-9 of gestation were studied in dairy cows and heifers (N = 211) on two farms. Cows were examined by ultrasonography for presence of a viable embryo, and sizes of the corpus luteum (CL) and of follicles > or = 5mm were recorded. Blood samples were taken at each examination and assayed for progesterone and estradiol. Overall pregnancy loss was 11.4%. Cows with two CL did not have greater concentrations of progesterone than cows with one CL and they retained fewer pregnancies (P < 0.01; 73% versus 91%). Pregnancy retention was associated positively with concentrations of progesterone and estradiol during week 5 (P < 0.05). Embryos that were lost apparently died before CL regression. Retention of pregnancy declined in cows with high body condition and as age of the cow increased. Pregnancy retention was lower in cows bred to one of four frequently-used service sires (P < 0.05). Days postpartum, milk production, parity, service number, inseminator, synchronization of estrus, diameter of follicles and size of CL did not affect pregnancy retention. In conclusion, retention of pregnancy during placentation varied with concentrations of progesterone and estradiol, age of cow, body condition and service sire.

Impaired hand size estimation in CRPS.

PubMed

Peltz, Elena; Seifert, Frank; Lanz, Stefan; Müller, Rüdiger; Maihöfner, Christian

2011-10-01

A triad of clinical symptoms, ie, autonomic, motor and sensory dysfunctions, characterizes complex regional pain syndromes (CRPS). Sensory dysfunction comprises sensory loss or spontaneous and stimulus-evoked pain. Furthermore, a disturbance in the body schema may occur. In the present study, patients with CRPS of the upper extremity and healthy controls estimated their hand sizes on the basis of expanded or compressed schematic drawings of hands. In patients with CRPS we found an impairment in accurate hand size estimation; patients estimated their own CRPS-affected hand to be larger than it actually was when measured objectively. Moreover, overestimation correlated significantly with disease duration, neglect score, and increase of two-point-discrimination-thresholds (TPDT) compared to the unaffected hand and to control subjects' estimations. In line with previous functional imaging studies in CRPS patients demonstrating changes in central somatotopic maps, we suggest an involvement of the central nervous system in this disruption of the body schema. Potential cortical areas may be the primary somatosensory and posterior parietal cortices, which have been proposed to play a critical role in integrating visuospatial information. CRPS patients perceive their affected hand to be bigger than it is. The magnitude of this overestimation correlates with disease duration, decreased tactile thresholds, and neglect-score. Suggesting a disrupted body schema as the source of this impairment, our findings corroborate the current assumption of a CNS involvement in CRPS. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

Prediction of anthropometric accommodation in aircraft cockpits

NASA Astrophysics Data System (ADS)

Zehner, Gregory Franklin

Designing aircraft cockpits to accommodate the wide range of body sizes existing in the U.S. population has always been a difficult problem for Crewstation Engineers. The approach taken in the design of military aircraft has been to restrict the range of body sizes allowed into flight training, and then to develop standards and specifications to ensure that the majority of the pilots are accommodated. Accommodation in this instance is defined as the ability to: (1) Adequately see, reach, and actuate controls; (2) Have external visual fields so that the pilot can see to land, clear for other aircraft, and perform a wide variety of missions (ground support/attack or air to air combat); and (3) Finally, if problems arise, the pilot has to be able to escape safely. Each of these areas is directly affected by the body size of the pilot. Unfortunately, accommodation problems persist and may get worse. Currently the USAF is considering relaxing body size entrance requirements so that smaller and larger people could become pilots. This will make existing accommodation problems much worse. This dissertation describes a methodology for correcting this problem and demonstrates the method by predicting pilot fit and performance in the USAF T-38A aircraft based on anthropometric data. The methods described can be applied to a variety of design applications where fitting the human operator into a system is a major concern. A systematic approach is described which includes: defining the user population, setting functional requirements that operators must be able to perform, testing the ability of the user population to perform the functional requirements, and developing predictive equations for selecting future users of the system. Also described is a process for the development of new anthropometric design criteria and cockpit design methods that assure body size accommodation is improved in the future.

Variability in body size and shape of UK offshore workers: A cluster analysis approach.

PubMed

Stewart, Arthur; Ledingham, Robert; Williams, Hector

2017-01-01

Male UK offshore workers have enlarged dimensions compared with UK norms and knowledge of specific sizes and shapes typifying their physiques will assist a range of functions related to health and ergonomics. A representative sample of the UK offshore workforce (n = 588) underwent 3D photonic scanning, from which 19 extracted dimensional measures were used in k-means cluster analysis to characterise physique groups. Of the 11 resulting clusters four somatotype groups were expressed: one cluster was muscular and lean, four had greater muscularity than adiposity, three had equal adiposity and muscularity and three had greater adiposity than muscularity. Some clusters appeared constitutionally similar to others, differing only in absolute size. These cluster centroids represent an evidence-base for future designs in apparel and other applications where body size and proportions affect functional performance. They also constitute phenotypic evidence providing insight into the 'offshore culture' which may underpin the enlarged dimensions of offshore workers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sea urchins in a high-CO2 world: partitioned effects of body size, ocean warming and acidification on metabolic rate.

PubMed

Carey, Nicholas; Harianto, Januar; Byrne, Maria

2016-04-15

Body size and temperature are the major factors explaining metabolic rate, and the additional factor of pH is a major driver at the biochemical level. These three factors have frequently been found to interact, complicating the formulation of broad models predicting metabolic rates and hence ecological functioning. In this first study of the effects of warming and ocean acidification, and their potential interaction, on metabolic rate across a broad range in body size (two to three orders of magnitude difference in body mass), we addressed the impact of climate change on the sea urchin ITALIC! Heliocidaris erythrogrammain context with climate projections for southeast Australia, an ocean warming hotspot. Urchins were gradually introduced to two temperatures (18 and 23°C) and two pH levels (7.5 and 8.0), at which they were maintained for 2 months. Identical experimental trials separated by several weeks validated the fact that a new physiological steady state had been reached, otherwise known as acclimation. The relationship between body size, temperature and acidification on the metabolic rate of ITALIC! H. erythrogrammawas strikingly stable. Both stressors caused increases in metabolic rate: 20% for temperature and 19% for pH. Combined effects were additive: a 44% increase in metabolism. Body size had a highly stable relationship with metabolic rate regardless of temperature or pH. None of these diverse drivers of metabolism interacted or modulated the effects of the others, highlighting the partitioned nature of how each influences metabolic rate, and the importance of achieving a full acclimation state. Despite these increases in energetic demand there was very limited capacity for compensatory modulating of feeding rate; food consumption increased only in the very smallest specimens, and only in response to temperature, and not pH. Our data show that warming, acidification and body size all substantially affect metabolism and are highly consistent and partitioned in their effects, and for ITALIC! H. erythrogramma, near-future climate change will incur a substantial energetic cost. © 2016. Published by The Company of Biologists Ltd.

The plasma wake of mesosonic conducting bodies. II - An experimental parametric study of the mid-wake ion density peak

NASA Technical Reports Server (NTRS)

Stone, N. H.

1981-01-01

An experimental investigation of the disturbed flow field created by conducting bodies in a mesosonic, collisionless plasma stream is reported. The mid-wake region is investigated, where, for bodies of the order of a Debye length in size, the focused ion streams converge to form a significant current density peak on the wake axis. A parametric description is obtained of the behavior of the amplitude, width, and position of this peak. The results also indicate that portions of the axial ion peak are created by additional mechanisms and that body geometry affects the mid-wake structure only when the sheath is sufficiently thin to conform to the shape of the body.

Beetle Exoskeleton May Facilitate Body Heat Acting Differentially across the Electromagnetic Spectrum.

PubMed

Carrascal, Luis M; Ruiz, Yolanda Jiménez; Lobo, Jorge M

Exoskeletons of beetles and their associated morphological characteristics can serve many different functions, including thermoregulation. We study the thermal role of the exoskeleton in 13 Geotrupidae dung beetle species using heating experiments under controlled conditions. The main purpose was to measure the influence of heating sources (solar radiance vs. infrared), animal position (dorsal exposure vs. ventral exposure), species identity, and phylogenetic relationships on internal asymptotic temperatures and heating rates. The thermal response was significantly influenced by phylogenetic relatedness, although it was not affected by the apterous condition. The asymptotic internal temperature of specimens was not affected by the thoracic volume but was significantly higher under simulated sunlight conditions than under infrared radiation and when exposed dorsally as opposed to ventrally. There was thus a significant interaction between heating source and body position. Heating rate was negatively and significantly influenced by thoracic volume, and, although insignificantly slower under simulated sunlight, it was significantly affected by body position, being faster under dorsal exposure. The results constitute the first evidence supporting the hypothesis that the beetle exoskeleton acts differentially across the electromagnetic spectrum determining internal body temperatures. This interesting finding suggests the existence of a kind of passive physiology imposed by the exoskeleton and body size, where interspecific relationships play a minor role.

Egg size and laying order of snowy egrets, great egrets, and black-crowned night-herons

USGS Publications Warehouse

Custer, T.W.; Frederick, P.C.

1990-01-01

The nesting biology of the family Ardeidae (bitterns, herons, and egrets) has been intensively studied (e.g., Owen 1960, Milstein et al. 1970, Werschkul 1979), but egg size in relation to laying order bas not received attention. The last egg laid in gull and tern clutches is generally smaller than preceding eggs (e.g., Parsons 1970, Nisbet 1978). The relative size of the final egg in a clutch decreases with increased body size among bird species and this relationship may be correlated with an increased brood-reduction strategy (Slagsvold et al. 1984). Relative egg size could be an important component to brood reduction, because egg size can affect subsequent survival of young (Parsons 1970, Nisbet 1978, Lundberg and Vaisanen 1979).

A fitness trade-off between seasons causes multigenerational cycles in phenotype and population size

PubMed Central

Betini, Gustavo S; McAdam, Andrew G; Griswold, Cortland K; Norris, D Ryan

2017-01-01

Although seasonality is widespread and can cause fluctuations in the intensity and direction of natural selection, we have little information about the consequences of seasonal fitness trade-offs for population dynamics. Here we exposed populations of Drosophila melanogaster to repeated seasonal changes in resources across 58 generations and used experimental and mathematical approaches to investigate how viability selection on body size in the non-breeding season could affect demography. We show that opposing seasonal episodes of natural selection on body size interacted with both direct and delayed density dependence to cause populations to undergo predictable multigenerational density cycles. Our results provide evidence that seasonality can set the conditions for life-history trade-offs and density dependence, which can, in turn, interact to cause multigenerational population cycles. DOI: http://dx.doi.org/10.7554/eLife.18770.001 PMID:28164780

Asymmetric forceps increase fighting success among males of similar size in the maritime earwig

PubMed Central

Munoz, Nicole E.; Zink, Andrew G.

2012-01-01

Extreme asymmetric morphologies are hypothesized to serve an adaptive function that counteracts sexual selection for symmetry. However direct tests of function for asymmetries are lacking, particularly in the context of animal weapons. The weapon of the maritime earwig, Anisolabis maritima, exhibits sizeable variation in the extent of directional asymmetry within and across body sizes, making it an ideal candidate for investigating the function of asymmetry. In this study, we characterized the extent of weapon asymmetry, characterized the manner in which asymmetric weapons are used in contests, staged dyadic contests between males of different size classes and analyzed the correlates of fighting success. In contests between large males, larger individuals won more fights and emerged as the dominant male. In contests between small males, however, weapon asymmetry was more influential in predicting overall fighting success than body size. This result reveals an advantage of asymmetric weaponry among males that are below the mean size in the population. A forceps manipulation experiment suggests that asymmetry may be an indirect, correlate of a morphologically independent factor that affects fighting ability. PMID:22984320

No evidence of nonlinear effects of predator density, refuge availability, or body size of prey on prey mortality rates.

PubMed

Simkins, Richard M; Belk, Mark C

2017-08-01

Predator density, refuge availability, and body size of prey can all affect the mortality rate of prey. We assume that more predators will lead to an increase in prey mortality rate, but behavioral interactions between predators and prey, and availability of refuge, may lead to nonlinear effects of increased number of predators on prey mortality rates. We tested for nonlinear effects in prey mortality rates in a mesocosm experiment with different size classes of western mosquitofish ( Gambusia affinis ) as the prey, different numbers of green sunfish ( Lepomis cyanellus ) as the predators, and different levels of refuge. Predator number and size class of prey, but not refuge availability, had significant effects on the mortality rate of prey. Change in mortality rate of prey was linear and equal across the range of predator numbers. Each new predator increased the mortality rate by about 10% overall, and mortality rates were higher for smaller size classes. Predator-prey interactions at the individual level may not scale up to create nonlinearity in prey mortality rates with increasing predator density at the population level.

Patterns of genome size variation in snapping shrimp.

PubMed

Jeffery, Nicholas W; Hultgren, Kristin; Chak, Solomon Tin Chi; Gregory, T Ryan; Rubenstein, Dustin R

2016-06-01

Although crustaceans vary extensively in genome size, little is known about how genome size may affect the ecology and evolution of species in this diverse group, in part due to the lack of large genome size datasets. Here we investigate interspecific, intraspecific, and intracolony variation in genome size in 39 species of Synalpheus shrimps, representing one of the largest genome size datasets for a single genus within crustaceans. We find that genome size ranges approximately 4-fold across Synalpheus with little phylogenetic signal, and is not related to body size. In a subset of these species, genome size is related to chromosome size, but not to chromosome number, suggesting that despite large genomes, these species are not polyploid. Interestingly, there appears to be 35% intraspecific genome size variation in Synalpheus idios among geographic regions, and up to 30% variation in Synalpheus duffyi genome size within the same colony.

The National Learning Disabilities Postsecondary Databank: An Overview.

ERIC Educational Resources Information Center

Vogel, Susan A.; Leonard, Faith; Scales, William; Hayeslip, Peggy; Hermansen, Jane; Donnells, Linda

1998-01-01

A survey of postsecondary institutions (N=147) assessed support services, procedures, policies, and the proportions of students with learning disabilities (LD). Findings indicated .5% to almost 10% of students with LD. Factors affecting this group included size of the student body, type of institution, the institution's Carnegie classification,…

Morphological and colour morph clines along an altitudinal gradient in the meadow grasshopper Pseudochorthippus parallelus.

PubMed

Köhler, Günter; Samietz, Jörg; Schielzeth, Holger

2017-01-01

Many animals show altitudinal clines in size, shape and body colour. Increases in body size and reduction in the length of body appendices in colder habitats are usually attributed to improved heat conservation at lower surface-to-volume ratios (known as Bergmann's and Allen's rule, respectively). However, the patterns are more variable and sometimes reversed in small ectotherms that are affected by shortened growing seasons. Altitude can also affect colouration. The thermal melanism hypothesis predicts darker colours under cooler conditions because of a thermoregulatory advantage. Darker colours may also be favoured at high altitudes for reasons of UV protection or habitat-dependent crypsis. We studied altitudinal variation in morphology and colour in the colour-polymorphic meadow grasshopper Pseudochorthippus parallelus based on 563 individuals from 17 populations sampled between 450 and 2,500 m asl. Pronotum length did not change with altitude, while postfemur length decreased significantly in both sexes. Tegmen (forewing) length decreased in males, but not in females. The results indicate that while body size, as best quantified by pronotum length, was remarkably constant, extended appendices were reduced at high altitudes. The pattern thus follows Allen's rule, but neither Bergmann's nor converse Bergmann's rule. These results indicate that inference of converse Bergmann's rule based on measurements from appendices should be treated with some caution. Colour morph ratios showed significant changes in both sexes from lowland populations dominated by green individuals to high-altitude populations dominated by brown ones. The increase of brown morphs was particularly steep between 1,500 and 2,000 m asl. The results suggest shared control of colour in males and females and local adaptation along the altitudinal gradient following the predictions of the thermal melanism hypothesis. Interestingly, both patterns, the reduction of body appendices and the higher frequency of brown individuals, may be explained by a need for efficient thermoregulation under high-altitude conditions.

Trait-based prediction of extinction risk of small-bodied freshwater fishes.

PubMed

Kopf, R Keller; Shaw, Casey; Humphries, Paul

2017-06-01

Small body size is generally correlated with r-selected life-history traits, including early maturation, short-generation times, and rapid growth rates, that result in high population turnover and a reduced risk of extinction. Unlike other classes of vertebrates, however, small freshwater fishes appear to have an equal or greater risk of extinction than large fishes. We explored whether particular traits explain the International Union for Conservation of Nature (IUCN) Red List conservation status of small-bodied freshwater fishes from 4 temperate river basins: Murray-Darling, Australia; Danube, Europe; Mississippi-Missouri, North America; and the Rio Grande, North America. Twenty-three ecological and life-history traits were collated for all 171 freshwater fishes of ≤120 mm total length. We used generalized linear mixed-effects models to assess which combination of the 23 traits best explained whether a species was threatened or not threatened. We used the best models to predict the probability of 29 unclassified species being listed as threatened. With and without controlling for phylogeny at the family level, small body size-among small-bodied species-was the most influential trait correlated with threatened species listings. The k-folds cross-validation demonstrated that body size and a random effect structure that included family predicted the threat status with an accuracy of 78% (SE 0.5). We identified 10 species likely to be threatened that are not listed as such on the IUCN Red List. Small body size is not a trait that provides universal resistance to extinction, particularly for vertebrates inhabiting environments affected by extreme habitat loss and fragmentation. We hypothesize that this is because small-bodied species have smaller home ranges, lower dispersal capabilities, and heightened ecological specialization relative to larger vertebrates. Trait data and further model development are needed to predict the IUCN conservation status of the over 11,000 unclassified freshwater fishes, especially those under threat from proposed dam construction in the world's most biodiverse river basins. © 2016 Society for Conservation Biology.

Microclimatic Divergence in a Mediterranean Canyon Affects Richness, Composition, and Body Size in Saproxylic Beetle Assemblages.

PubMed

Buse, Jörn; Fassbender, Samuel; Entling, Martin H; Pavlicek, Tomas

2015-01-01

Large valleys with opposing slopes may act as a model system with which the effects of strong climatic gradients on biodiversity can be evaluated. The advantage of such comparisons is that the impact of a change of climate can be studied on the same species pool without the need to consider regional differences. The aim of this study was to compare the assemblage of saproxylic beetles on such opposing slopes at Lower Nahal Oren, Mt. Carmel, Israel (also known as "Evolution Canyon") with a 200-800% higher solar radiation on the south-facing (SFS) compared to the north-facing slope (NFS). We tested specific hypotheses of species richness patterns, assemblage structure, and body size resulting from interslope differences in microclimate. Fifteen flight-interception traps per slope were distributed over three elevation levels ranging from 50 to 100 m a.s.l. Richness of saproxylic beetles was on average 34% higher on the SFS compared with the NFS, with no detected influence of elevation levels. Both assemblage structure and average body size were determined by slope aspect, with more small-bodied beetles found on the SFS. Both the increase in species richness and the higher prevalence of small species on the SFS reflect ecological rules present on larger spatial grain (species-energy hypothesis and community body size shift hypothesis), and both can be explained by the metabolic theory of ecology. This is encouraging for the complementary use of micro- and macroclimatic gradients to study impacts of climate warming on biodiversity.

Disentangling the phylogenetic and ecological components of spider phenotypic variation.

PubMed

Gonçalves-Souza, Thiago; Diniz-Filho, José Alexandre Felizola; Romero, Gustavo Quevedo

2014-01-01

An understanding of how the degree of phylogenetic relatedness influences the ecological similarity among species is crucial to inferring the mechanisms governing the assembly of communities. We evaluated the relative importance of spider phylogenetic relationships and ecological niche (plant morphological variables) to the variation in spider body size and shape by comparing spiders at different scales: (i) between bromeliads and dicot plants (i.e., habitat scale) and (ii) among bromeliads with distinct architectural features (i.e., microhabitat scale). We partitioned the interspecific variation in body size and shape into phylogenetic (that express trait values as expected by phylogenetic relationships among species) and ecological components (that express trait values independent of phylogenetic relationships). At the habitat scale, bromeliad spiders were larger and flatter than spiders associated with the surrounding dicots. At this scale, plant morphology sorted out close related spiders. Our results showed that spider flatness is phylogenetically clustered at the habitat scale, whereas it is phylogenetically overdispersed at the microhabitat scale, although phylogenic signal is present in both scales. Taken together, these results suggest that whereas at the habitat scale selective colonization affect spider body size and shape, at fine scales both selective colonization and adaptive evolution determine spider body shape. By partitioning the phylogenetic and ecological components of phenotypic variation, we were able to disentangle the evolutionary history of distinct spider traits and show that plant architecture plays a role in the evolution of spider body size and shape. We also discussed the relevance in considering multiple scales when studying phylogenetic community structure.

Disentangling the Phylogenetic and Ecological Components of Spider Phenotypic Variation

PubMed Central

Gonçalves-Souza, Thiago; Diniz-Filho, José Alexandre Felizola; Romero, Gustavo Quevedo

2014-01-01

An understanding of how the degree of phylogenetic relatedness influences the ecological similarity among species is crucial to inferring the mechanisms governing the assembly of communities. We evaluated the relative importance of spider phylogenetic relationships and ecological niche (plant morphological variables) to the variation in spider body size and shape by comparing spiders at different scales: (i) between bromeliads and dicot plants (i.e., habitat scale) and (ii) among bromeliads with distinct architectural features (i.e., microhabitat scale). We partitioned the interspecific variation in body size and shape into phylogenetic (that express trait values as expected by phylogenetic relationships among species) and ecological components (that express trait values independent of phylogenetic relationships). At the habitat scale, bromeliad spiders were larger and flatter than spiders associated with the surrounding dicots. At this scale, plant morphology sorted out close related spiders. Our results showed that spider flatness is phylogenetically clustered at the habitat scale, whereas it is phylogenetically overdispersed at the microhabitat scale, although phylogenic signal is present in both scales. Taken together, these results suggest that whereas at the habitat scale selective colonization affect spider body size and shape, at fine scales both selective colonization and adaptive evolution determine spider body shape. By partitioning the phylogenetic and ecological components of phenotypic variation, we were able to disentangle the evolutionary history of distinct spider traits and show that plant architecture plays a role in the evolution of spider body size and shape. We also discussed the relevance in considering multiple scales when studying phylogenetic community structure. PMID:24651264

Kleiber's Law: How the Fire of Life ignited debate, fueled theory, and neglected plants as model organisms

PubMed Central

Niklas, Karl J; Kutschera, Ulrich

2015-01-01

Size is a key feature of any organism since it influences the rate at which resources are consumed and thus affects metabolic rates. In the 1930s, size-dependent relationships were codified as “allometry” and it was shown that most of these could be quantified using the slopes of log-log plots of any 2 variables of interest. During the decades that followed, physiologists explored how animal respiration rates varied as a function of body size across taxa. The expectation was that rates would scale as the 2/3 power of body size as a reflection of the Euclidean relationship between surface area and volume. However, the work of Max Kleiber (1893–1976) and others revealed that animal respiration rates apparently scale more closely as the 3/4 power of body size. This phenomenology, which is called “Kleiber's Law,” has been described for a broad range of organisms, including some algae and plants. It has also been severely criticized on theoretical and empirical grounds. Here, we review the history of the analysis of metabolism, which originated with the works of Antoine L. Lavoisier (1743–1794) and Julius Sachs (1832–1897), and culminated in Kleiber's book The Fire of Life (1961; 2. ed. 1975). We then evaluate some of the criticisms that have been leveled against Kleiber's Law and some examples of the theories that have tried to explain it. We revive the speculation that intracellular exo- and endocytotic processes are resource delivery-systems, analogous to the supercellular systems in multicellular organisms. Finally, we present data that cast doubt on the existence of a single scaling relationship between growth and body size in plants. PMID:26156204

Kleiber's Law: How the Fire of Life ignited debate, fueled theory, and neglected plants as model organisms.

PubMed

Niklas, Karl J; Kutschera, Ulrich

2015-01-01

Size is a key feature of any organism since it influences the rate at which resources are consumed and thus affects metabolic rates. In the 1930s, size-dependent relationships were codified as "allometry" and it was shown that most of these could be quantified using the slopes of log-log plots of any 2 variables of interest. During the decades that followed, physiologists explored how animal respiration rates varied as a function of body size across taxa. The expectation was that rates would scale as the 2/3 power of body size as a reflection of the Euclidean relationship between surface area and volume. However, the work of Max Kleiber (1893-1976) and others revealed that animal respiration rates apparently scale more closely as the 3/4 power of body size. This phenomenology, which is called "Kleiber's Law," has been described for a broad range of organisms, including some algae and plants. It has also been severely criticized on theoretical and empirical grounds. Here, we review the history of the analysis of metabolism, which originated with the works of Antoine L. Lavoisier (1743-1794) and Julius Sachs (1832-1897), and culminated in Kleiber's book The Fire of Life (1961; 2. ed. 1975). We then evaluate some of the criticisms that have been leveled against Kleiber's Law and some examples of the theories that have tried to explain it. We revive the speculation that intracellular exo- and endocytotic processes are resource delivery-systems, analogous to the supercellular systems in multicellular organisms. Finally, we present data that cast doubt on the existence of a single scaling relationship between growth and body size in plants.

Fossils and living taxa agree on patterns of body mass evolution: a case study with Afrotheria.

PubMed

Puttick, Mark N; Thomas, Gavin H

2015-12-22

Most of life is extinct, so incorporating some fossil evidence into analyses of macroevolution is typically seen as necessary to understand the diversification of life and patterns of morphological evolution. Here we test the effects of inclusion of fossils in a study of the body size evolution of afrotherian mammals, a clade that includes the elephants, sea cows and elephant shrews. We find that the inclusion of fossil tips has little impact on analyses of body mass evolution; from a small ancestral size (approx. 100 g), there is a shift in rate and an increase in mass leading to the larger-bodied Paenungulata and Tubulidentata, regardless of whether fossils are included or excluded from analyses. For Afrotheria, the inclusion of fossils and morphological character data affect phylogenetic topology, but these differences have little impact upon patterns of body mass evolution and these body mass evolutionary patterns are consistent with the fossil record. The largest differences between our analyses result from the evolutionary model, not the addition of fossils. For some clades, extant-only analyses may be reliable to reconstruct body mass evolution, but the addition of fossils and careful model selection is likely to increase confidence and accuracy of reconstructed macroevolutionary patterns. © 2015 The Authors.

Fossils and living taxa agree on patterns of body mass evolution: a case study with Afrotheria

PubMed Central

Puttick, Mark N.; Thomas, Gavin H.

2015-01-01

Most of life is extinct, so incorporating some fossil evidence into analyses of macroevolution is typically seen as necessary to understand the diversification of life and patterns of morphological evolution. Here we test the effects of inclusion of fossils in a study of the body size evolution of afrotherian mammals, a clade that includes the elephants, sea cows and elephant shrews. We find that the inclusion of fossil tips has little impact on analyses of body mass evolution; from a small ancestral size (approx. 100 g), there is a shift in rate and an increase in mass leading to the larger-bodied Paenungulata and Tubulidentata, regardless of whether fossils are included or excluded from analyses. For Afrotheria, the inclusion of fossils and morphological character data affect phylogenetic topology, but these differences have little impact upon patterns of body mass evolution and these body mass evolutionary patterns are consistent with the fossil record. The largest differences between our analyses result from the evolutionary model, not the addition of fossils. For some clades, extant-only analyses may be reliable to reconstruct body mass evolution, but the addition of fossils and careful model selection is likely to increase confidence and accuracy of reconstructed macroevolutionary patterns. PMID:26674947

Body shape ideals across gender, sexual orientation, socioeconomic status, race, and age in personal advertisements.

PubMed

Epel, E S; Spanakos, A; Kasl-Godley, J; Brownell, K D

1996-04-01

To assess body shape ideals across gender, sexual orientation, race, socio-economic status, and age, An analysis of personal advertisements was conducted across seven different publications which targeted the groups of interest. Women advertised body weight much less often than men, and lesbians reported body shape descriptors significantly less often than heterosexual women. Gay men and African-American men described their body shape significantly more often than did other groups. However, their reported body mass indices (BMI) were significantly different-African-American men reported a higher BMI, and gay men a lower BMI, than Euro-American heterosexual men. Race and sexual orientation may influence the importance of size of body shape ideals for men. For women, however, their advertised weights conformed to the thin ideal across all groups surveyed. Gender roles affecting body shape ideals and mate attraction are discussed.

Illusory Obesity Triggers Body Dissatisfaction Responses in the Insula and Anterior Cingulate Cortex

PubMed Central

Preston, Catherine; Ehrsson, H. Henrik

2016-01-01

In today's Western society, concerns regarding body size and negative feelings toward one's body are all too common. However, little is known about the neural mechanisms underlying negative feelings toward the body and how they relate to body perception and eating-disorder pathology. Here, we used multisensory illusions to elicit illusory ownership of obese and slim bodies during functional magnetic resonance imaging. The results implicate the anterior insula and the anterior cingulate cortex in the development of negative feelings toward the body through functional interactions with the posterior parietal cortex, which mediates perceived obesity. Moreover, cingulate neural responses were modulated by nonclinical eating-disorder psychopathology and were attenuated in females. These results reveal how perceptual and affective body representations interact in the human brain and may help explain the neurobiological underpinnings of eating-disorder vulnerability in women. PMID:27733537

Fish movement and habitat use depends on water body size and shape

USGS Publications Warehouse

Woolnough, D.A.; Downing, J.A.; Newton, T.J.

2009-01-01

Home ranges are central to understanding habitat diversity, effects of fragmentation and conservation. The distance that an organism moves yields information on life history, genetics and interactions with other organisms. Present theory suggests that home range is set by body size of individuals. Here, we analyse estimates of home ranges in lakes and rivers to show that body size of fish and water body size and shape influence home range size. Using 71 studies including 66 fish species on five continents, we show that home range estimates increased with increasing water body size across water body shapes. This contrasts with past studies concluding that body size sets home range. We show that water body size was a consistently significant predictor of home range. In conjunction, body size and water body size can provide improved estimates of home range than just body size alone. As habitat patches are decreasing in size worldwide, our findings have implications for ecology, conservation and genetics of populations in fragmented ecosystems. ?? 2008 Blackwell Munksgaard.

Body Size Diversity and Frequency Distributions of Neotropical Cichlid Fishes (Cichliformes: Cichlidae: Cichlinae)

PubMed Central

Steele, Sarah E.; López-Fernández, Hernán

2014-01-01

Body size is an important correlate of life history, ecology and distribution of species. Despite this, very little is known about body size evolution in fishes, particularly freshwater fishes of the Neotropics where species and body size diversity are relatively high. Phylogenetic history and body size data were used to explore body size frequency distributions in Neotropical cichlids, a broadly distributed and ecologically diverse group of fishes that is highly representative of body size diversity in Neotropical freshwater fishes. We test for divergence, phylogenetic autocorrelation and among-clade partitioning of body size space. Neotropical cichlids show low phylogenetic autocorrelation and divergence within and among taxonomic levels. Three distinct regions of body size space were identified from body size frequency distributions at various taxonomic levels corresponding to subclades of the most diverse tribe, Geophagini. These regions suggest that lineages may be evolving towards particular size optima that may be tied to specific ecological roles. The diversification of Geophagini appears to constrain the evolution of body size among other Neotropical cichlid lineages; non-Geophagini clades show lower species-richness in body size regions shared with Geophagini. Neotropical cichlid genera show less divergence and extreme body size than expected within and among tribes. Body size divergence among species may instead be present or linked to ecology at the community assembly scale. PMID:25180970

Individual variation in functional response parameters is explained by body size but not by behavioural types in a poeciliid fish.

PubMed

Schröder, Arne; Kalinkat, Gregor; Arlinghaus, Robert

2016-12-01

Functional responses are per-capita feeding rate models whose parameters often scale with individual body size but the parameters may also be further influenced by behavioural traits consistently differing among individuals, i.e. behavioural types or animal personalities. Behavioural types may intrinsically lead to lower feeding rates when consistently shy, inactive and easily stressed individuals cannot identify or respond to risk-free environments or need less food due to lower metabolic rates linked to behaviour. To test how much variation in functional response parameters is explained by body size and how much by behavioural types, we estimated attack rate and handling time individually for differently sized female least killifish (Heterandria formosa) and repeatedly measured behavioural traits for each individual. We found that individual fish varied substantially in their attack rate and in their handling time. Behavioural traits were stable over time and varied consistently among individuals along two distinct personality axes. The individual variation in functional responses was explained solely by body size, and contrary to our expectations, not additionally by the existing behavioural types in exploration activity and coping style. While behavioural trait-dependent functional responses may offer a route to the understanding of the food web level consequences of behavioural types, our study is so far only the second one on this topic. Importantly, our results indicate in contrast to that previous study that behavioural types do not per se affect individual functional responses assessed in the absence of external biotic stressors.

Roosevelt elk density and social segregation: Foraging behavior and females avoiding larger groups of males

USGS Publications Warehouse

Weckerly, F.; McFarland, K.; Ricca, M.; Meyer, K.

2004-01-01

Intersexual social segregation at small spatial scales is prevalent in ruminants that are sexually dimorphic in body size. Explaining social segregation, however, from hypotheses of how intersexual size differences affects the foraging process of males and females has had mixed results. We studied whether body size influences on forage behavior, intersexual social incompatibility or both might influence social segregation in a population of Roosevelt elk (Cervus elaphus roosevelt) that declined 40% over 5 y. Most males and females in the population occurred in the same forage patches, meadows, but occupied different parts of meadows and most groups were overwhelming comprised of one sex. The extent of segregation varied slightly with changing elk density. Cropping rate, our surrogate of forage ingestion, of males in mixed-sex groups differed from males in male-only groups at high, but not low, elk density. In a prior study of intersexual social interactions it was shown that females avoided groups containing ???6 males. Therefore, we predicted that females should avoid parts of meadows where groups of males ???6 were prevalent. Across the 5 y of study this prediction held because ???5% of all females were found in parts of meadows where median aggregation sizes of males were ???6. Social segregation was coupled to body size influences on forage ingestion at high density and social incompatibility was coupled to social segregation regardless of elk density.

How does abundance scale with body size in coupled size-structured food webs?

PubMed

Blanchard, Julia L; Jennings, Simon; Law, Richard; Castle, Matthew D; McCloghrie, Paul; Rochet, Marie-Joëlle; Benoît, Eric

2009-01-01

1. Widely observed macro-ecological patterns in log abundance vs. log body mass of organisms can be explained by simple scaling theory based on food (energy) availability across a spectrum of body sizes. The theory predicts that when food availability falls with body size (as in most aquatic food webs where larger predators eat smaller prey), the scaling between log N vs. log m is steeper than when organisms of different sizes compete for a shared unstructured resource (e.g. autotrophs, herbivores and detritivores; hereafter dubbed 'detritivores'). 2. In real communities, the mix of feeding characteristics gives rise to complex food webs. Such complexities make empirical tests of scaling predictions prone to error if: (i) the data are not disaggregated in accordance with the assumptions of the theory being tested, or (ii) the theory does not account for all of the trophic interactions within and across the communities sampled. 3. We disaggregated whole community data collected in the North Sea into predator and detritivore components and report slopes of log abundance vs. log body mass relationships. Observed slopes for fish and epifaunal predator communities (-1.2 to -2.25) were significantly steeper than those for infaunal detritivore communities (-0.56 to -0.87). 4. We present a model describing the dynamics of coupled size spectra, to explain how coupling of predator and detritivore communities affects the scaling of log N vs. log m. The model captures the trophic interactions and recycling of material that occur in many aquatic ecosystems. 5. Our simulations demonstrate that the biological processes underlying growth and mortality in the two distinct size spectra lead to patterns consistent with data. Slopes of log N vs. log m were steeper and growth rates faster for predators compared to detritivores. Size spectra were truncated when primary production was too low for predators and when detritivores experienced predation pressure. 6. The approach also allows us to assess the effects of external sources of mortality (e.g. harvesting). Removal of large predators resulted in steeper predator spectra and increases in their prey (small fish and detritivores). The model predictions are remarkably consistent with observed patterns of exploited ecosystems.

Comparison of proposed alternative methods for rescaling dialysis dose: resting energy expenditure, high metabolic rate organ mass, liver size, and body surface area.

PubMed

Daugirdas, John T; Levin, Nathan W; Kotanko, Peter; Depner, Thomas A; Kuhlmann, Martin K; Chertow, Glenn M; Rocco, Michael V

2008-01-01

A number of denominators for scaling the dose of dialysis have been proposed as alternatives to the urea distribution volume (V). These include resting energy expenditure (REE), mass of high metabolic rate organs (HMRO), visceral mass, and body surface area. Metabolic rate is an unlikely denominator as it varies enormously among humans with different levels of activity and correlates poorly with the glomerular filtration rate. Similarly, scaling based on HMRO may not be optimal, as many organs with high metabolic rates such as spleen, brain, and heart are unlikely to generate unusually large amounts of uremic toxins. Visceral mass, in particular the liver and gut, has potential merit as a denominator for scaling; liver size is related to protein intake and the liver, along with the gut, is known to be responsible for the generation of suspected uremic toxins. Surface area is time-honored as a scaling method for glomerular filtration rate and scales similarly to liver size. How currently recommended dialysis doses might be affected by these alternative rescaling methods was modeled by applying anthropometric equations to a large group of dialysis patients who participated in the HEMO study. The data suggested that rescaling to REE would not be much different from scaling to V. Scaling to HMRO mass would mandate substantially higher dialysis doses for smaller patients of either gender. Rescaling to liver mass would require substantially more dialysis for women compared with men at all levels of body size. Rescaling to body surface area would require more dialysis for smaller patients of either gender and also more dialysis for women of any size. Of these proposed alternative rescaling measures, body surface area may be the best, because it reflects gender-based scaling of liver size and thereby the rate of generation of uremic toxins.

The effect of temperature and body weight on the routine metabolic rate and postprandial metabolic response in mulloway, Argyrosomus japonicus.

PubMed

Pirozzi, Igor; Booth, Mark A

2009-09-01

Specific dynamic action (SDA) is the energy expended on the physiological processes associated with meal digestion and is strongly influenced by the characteristics of the meal and the body weight (BW) and temperature of the organism. This study assessed the effects of temperature and body weight on the routine metabolic rate (RMR) and postprandial metabolic response in mulloway, Argyrosomus japonicus. RMR and SDA were established at 3 temperatures (14, 20 and 26 degrees C). 5 size classes of mulloway ranging from 60 g to 1.14 kg were used to establish RMR with 3 of the 5 size classes (60, 120 and 240 g) used to establish SDA. The effect of body size on the mass-specific RMR (mg O(2) kg(-1) h(-1)) varied significantly depending on the temperature; there was a greater relative increase in the mass-specific RMR for smaller mulloway with increasing temperature. No statistical differences were found between the mass exponent (b) values at each temperature when tested against H(0): b=0.8. The gross RMR of mulloway (mg O(2) fish(-1) h(-1)) can be described as function of temperature (T; 14-26 degrees C) as: (0.0195T-0.0454)BW(g)(0.8) and the mass-specific RMR (mg O(2) kg(-1) h(-1)) can be described as: (21.042T-74.867)BW(g)(-0.2). Both SDA duration and time to peak SDA were influenced by temperature and body weight; SDA duration occurred within 41-89 h and peak time occurred within 17-38 h of feeding. The effect of body size on peak metabolic rate varied significantly depending on temperature, generally increasing with temperature and decreasing with increasing body size. Peak gross oxygen consumption (MO(2): mg O(2) fish(-1) h(-1)) scaled allometrically with BW. Temperature, but not body size, significantly affected SDA scope, although the difference was numerically small. There was a trend for MO(2) above RMR over the SDA period to increase with temperature; however, this was not statistically significant. The average proportion of energy expended over the SDA period (SDA coefficient) ranged from approximately 7-13% of the total DE intake while the proportion of total energy expended on SDA above RMR ranged from approximately 16-27%.

Evolution of body size in Galapagos marine iguanas.

PubMed

Wikelski, Martin

2005-10-07

Body size is one of the most important traits of organisms and allows predictions of an individual's morphology, physiology, behaviour and life history. However, explaining the evolution of complex traits such as body size is difficult because a plethora of other traits influence body size. Here I review what we know about the evolution of body size in a group of island reptiles and try to generalize about the mechanisms that shape body size. Galapagos marine iguanas occupy all 13 larger islands in this Pacific archipelago and have maximum island body weights between 900 and 12 000g. The distribution of body sizes does not match mitochondrial clades, indicating that body size evolves independently of genetic relatedness. Marine iguanas lack intra- and inter-specific food competition and predators are not size-specific, discounting these factors as selective agents influencing body size. Instead I hypothesize that body size reflects the trade-offs between sexual and natural selection. We found that sexual selection continuously favours larger body sizes. Large males establish display territories and some gain over-proportional reproductive success in the iguanas' mating aggregations. Females select males based on size and activity and are thus responsible for the observed mating skew. However, large individuals are strongly selected against during El Niño-related famines when dietary algae disappear from the intertidal foraging areas. We showed that differences in algae sward ('pasture') heights and thermal constraints on large size are causally responsible for differences in maximum body size among populations. I hypothesize that body size in many animal species reflects a trade-off between foraging constraints and sexual selection and suggest that future research could focus on physiological and genetic mechanisms determining body size in wild animals. Furthermore, evolutionary stable body size distributions within populations should be analysed to better understand selection pressures on individual body size.

Evolution of body size in Galapagos marine iguanas

PubMed Central

Wikelski, Martin

2005-01-01

Body size is one of the most important traits of organisms and allows predictions of an individual's morphology, physiology, behaviour and life history. However, explaining the evolution of complex traits such as body size is difficult because a plethora of other traits influence body size. Here I review what we know about the evolution of body size in a group of island reptiles and try to generalize about the mechanisms that shape body size. Galapagos marine iguanas occupy all 13 larger islands in this Pacific archipelago and have maximum island body weights between 900 and 12 000 g. The distribution of body sizes does not match mitochondrial clades, indicating that body size evolves independently of genetic relatedness. Marine iguanas lack intra- and inter-specific food competition and predators are not size-specific, discounting these factors as selective agents influencing body size. Instead I hypothesize that body size reflects the trade-offs between sexual and natural selection. We found that sexual selection continuously favours larger body sizes. Large males establish display territories and some gain over-proportional reproductive success in the iguanas' mating aggregations. Females select males based on size and activity and are thus responsible for the observed mating skew. However, large individuals are strongly selected against during El Niño-related famines when dietary algae disappear from the intertidal foraging areas. We showed that differences in algae sward (‘pasture’) heights and thermal constraints on large size are causally responsible for differences in maximum body size among populations. I hypothesize that body size in many animal species reflects a trade-off between foraging constraints and sexual selection and suggest that future research could focus on physiological and genetic mechanisms determining body size in wild animals. Furthermore, evolutionary stable body size distributions within populations should be analysed to better understand selection pressures on individual body size. PMID:16191607

Association between inaccurate estimation of body size and obesity in schoolchildren.

PubMed

Costa, Larissa da Cunha Feio; Silva, Diego Augusto Santos; Almeida, Sebastião de Sousa; de Vasconcelos, Francisco de Assis Guedes

2015-01-01

To investigate the prevalence of inaccurate estimation of own body size among Brazilian schoolchildren of both sexes aged 7-10 years, and to test whether overweight/obesity; excess body fat and central obesity are associated with inaccuracy. Accuracy of body size estimation was assessed using the Figure Rating Scale for Brazilian Children. Multinomial logistic regression was used to analyze associations. The overall prevalence of inaccurate body size estimation was 76%, with 34% of the children underestimating their body size and 42% overestimating their body size. Obesity measured by body mass index was associated with underestimation of body size in both sexes, while central obesity was only associated with overestimation of body size among girls. The results of this study suggest there is a high prevalence of inaccurate body size estimation and that inaccurate estimation is associated with obesity. Accurate estimation of own body size is important among obese schoolchildren because it may be the first step towards adopting healthy lifestyle behaviors.

Juvenile body mass estimation: A methodological evaluation.

PubMed

Cowgill, Libby

2018-02-01

Two attempts have been made to develop body mass prediction formulae specifically for immature remains: Ruff (Ruff, C.C., 2007, Body size prediction from juvenile skeletal remains. American Journal Physical Anthropology 133, 698-716) and Robbins et al. (Robbins, G., Sciulli, P.W., Blatt, S.H., 2010. Estimating body mass in subadult human skeletons. American Journal Physical Anthropology 143, 146-150). While both were developed from the same reference population, they differ in their independent variable selection: Ruff (2008) used measures of metaphyseal and articular surface size to predict body mass in immature remains, whereas Robbins et al. (2010) relied on cross-sectional properties. Both methods perform well on independent testing samples; however, differences between the two methods exist in the predicted values. This research evaluates the differences in the body mass estimates from these two methods in seven geographically diverse skeletal samples under the age of 18 (n = 461). The purpose of this analysis is not to assess which method performs with greater accuracy or precision; instead, differences between the two methods are used as a heuristic device to focus attention on the unique challenges affecting the prediction of immature body mass estimates in particular. The two methods differ by population only in some cases, which may be a reflection of activity variation or nutritional status. In addition, cross-sectional properties almost always produce higher estimates than metaphyseal surface size across all age categories. This highlights the difficulty in teasing apart information related to body mass from that relevant to loading, particularly when the original reference population is urban/industrial. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effects of "thin ideal" media on women's body image concerns and eating-related intentions: the beneficial role of an autonomous regulation of eating behaviors.

PubMed

Mask, Lisa; Blanchard, Céline M

2011-09-01

The present study examines the protective role of an autonomous regulation of eating behaviors (AREB) on the relationship between trait body dissatisfaction and women's body image concerns and eating-related intentions in response to "thin ideal" media. Undergraduate women (n=138) were randomly assigned to view a "thin ideal" video or a neutral video. As hypothesized, trait body dissatisfaction predicted more negative affect and size dissatisfaction following exposure to the "thin ideal" video among women who displayed less AREB. Conversely, trait body dissatisfaction predicted greater intentions to monitor food intake and limit unhealthy foods following exposure to the "thin ideal" video among women who displayed more AREB. Copyright © 2011 Elsevier Ltd. All rights reserved.

Association between different phases of menstrual cycle and body image measures of perceived size, ideal size, and body dissatisfaction.

PubMed

Teixeira, André Luiz S; Dias, Marcelo Ricardo C; Damasceno, Vinícius O; Lamounier, Joel A; Gardner, Rick M

2013-12-01

The association between phases of the menstrual cycle and body image was investigated. 44 university women (M age = 23.3 yr., SD = 4.7) judged their perceived and ideal body size, and body dissatisfaction was calculated at each phase of the menstrual cycle, including premenstrual, menstrual, and intermenstrual. Participants selected one of nine figural drawings ranging from very thin to obese that represented their perceived size and ideal size. Body dissatisfaction was measured as the absolute difference between scores on perceived and ideal figural drawings. During each menstrual phase, anthropometric measures of weight, height, body mass index, circumference of waist and abdomen, and body composition were taken. There were no significant differences in any anthropometric measures between the three menstrual cycle phases. Perceived body size and body dissatisfaction were significantly different between menstrual phases, with the largest perceived body size and highest body dissatisfaction occurring during the menstrual phase. Ideal body size did not differ between menstrual phases, although participants desired a significantly smaller ideal size as compared to the perceived size.

Body size estimation of self and others in females varying in BMI.

PubMed

Thaler, Anne; Geuss, Michael N; Mölbert, Simone C; Giel, Katrin E; Streuber, Stephan; Romero, Javier; Black, Michael J; Mohler, Betty J

2018-01-01

Previous literature suggests that a disturbed ability to accurately identify own body size may contribute to overweight. Here, we investigated the influence of personal body size, indexed by body mass index (BMI), on body size estimation in a non-clinical population of females varying in BMI. We attempted to disentangle general biases in body size estimates and attitudinal influences by manipulating whether participants believed the body stimuli (personalized avatars with realistic weight variations) represented their own body or that of another person. Our results show that the accuracy of own body size estimation is predicted by personal BMI, such that participants with lower BMI underestimated their body size and participants with higher BMI overestimated their body size. Further, participants with higher BMI were less likely to notice the same percentage of weight gain than participants with lower BMI. Importantly, these results were only apparent when participants were judging a virtual body that was their own identity (Experiment 1), but not when they estimated the size of a body with another identity and the same underlying body shape (Experiment 2a). The different influences of BMI on accuracy of body size estimation and sensitivity to weight change for self and other identity suggests that effects of BMI on visual body size estimation are self-specific and not generalizable to other bodies.

Body size estimation of self and others in females varying in BMI

PubMed Central

Geuss, Michael N.; Mölbert, Simone C.; Giel, Katrin E.; Streuber, Stephan; Romero, Javier; Black, Michael J.; Mohler, Betty J.

2018-01-01

Previous literature suggests that a disturbed ability to accurately identify own body size may contribute to overweight. Here, we investigated the influence of personal body size, indexed by body mass index (BMI), on body size estimation in a non-clinical population of females varying in BMI. We attempted to disentangle general biases in body size estimates and attitudinal influences by manipulating whether participants believed the body stimuli (personalized avatars with realistic weight variations) represented their own body or that of another person. Our results show that the accuracy of own body size estimation is predicted by personal BMI, such that participants with lower BMI underestimated their body size and participants with higher BMI overestimated their body size. Further, participants with higher BMI were less likely to notice the same percentage of weight gain than participants with lower BMI. Importantly, these results were only apparent when participants were judging a virtual body that was their own identity (Experiment 1), but not when they estimated the size of a body with another identity and the same underlying body shape (Experiment 2a). The different influences of BMI on accuracy of body size estimation and sensitivity to weight change for self and other identity suggests that effects of BMI on visual body size estimation are self-specific and not generalizable to other bodies. PMID:29425218

The geometric framework for nutrition reveals interactions between protein and carbohydrate during larval growth in honey bees

USDA-ARS?s Scientific Manuscript database

In holometabolous insects, larval nutrition affects adult body size, a life history trait with a profound influence on performance and fitness. Individual nutritional components of larval diet are often complex and may interact with one another, necessitating the use of a geometric framework for und...

Nutrient intake determines post-maturity molting in the golden orb-web spider Nephila pilipes (Araneae: Araneidae).

PubMed

Cheng, Ren-Chung; Zhang, Shichang; Chen, Yu-Chun; Lee, Chia-Yi; Chou, Yi-Ling; Ye, Hui-Ying; Piorkowski, Dakota; Liao, Chen-Pan; Tso, I-Min

2017-06-15

While molting occurs in the development of many animals, especially arthropods, post-maturity molting (PMM, organisms continue to molt after sexual maturity) has received little attention. The mechanism of molting has been studied intensively; however, the mechanism of PMM remains unknown although it is suggested to be crucial for the development of body size. In this study, we investigated factors that potentially induce PMM in the golden orb-web spider Nephila pilipes , which has the greatest degree of sexual dimorphism among terrestrial animals. We manipulated the mating history and the nutrient consumption of the females to examine whether they affect PMM. The results showed that female spiders under low nutrition were more likely to molt as adults, and mating had no significant influence on the occurrence of PMM. Moreover, spiders that underwent PMM lived longer than those that did not and their body sizes were significantly increased. Therefore, we concluded that nutritional condition rather than mating history affect PMM. © 2017. Published by The Company of Biologists Ltd.

Research of the relationship of pedestrian injury to collision speed, car-type, impact location and pedestrian sizes using human FE model (THUMS Version 4).

PubMed

Watanabe, Ryosuke; Katsuhara, Tadasuke; Miyazaki, Hiroshi; Kitagawa, Yuichi; Yasuki, Tsuyoshi

2012-10-01

Injuries in car to pedestrian collisions are affected by various factors such as the vehicle body type, pedestrian body size and impact location as well as the collision speed. This study aimed to investigate the influence of such factors taking a Finite Element (FE) approach. A total of 72 collision cases were simulated using three different vehicle FE models (Sedan, SUV, Mini-Van), three different pedestrian FE models (AM50, AF05, AM95), assuming two different impact locations (center and the corner of the bumper) and at four different collision speeds (20, 30, 40 and 50 km/h). The impact kinematics and the responses of the pedestrian model were validated against those in the literature prior to the simulations. The relationship between the collision speed and the predicted occurrence of head and chest injuries was examined for each case, analyzing the impact kinematics of the pedestrian against the vehicle body and resultant loading to the head and the chest. Strain based indicators were used in the simulation model to estimate skeletal injury (bony fracture) and soft tissue (brain and internal organs) injury. The study results primarily showed that the injury risk became higher with the collision speed, but was also affected by the combination of the factors such as the pedestrian size and the impact location. The study also discussed the injury patterns and trends with respect to the factors examined. In all of the simulated conditions, the model did not predict any severe injury at a collision speed of 20 km/h.

Early Life Conditions and Physiological Stress following the Transition to Farming in Central/Southeast Europe: Skeletal Growth Impairment and 6000 Years of Gradual Recovery

PubMed Central

Macintosh, Alison A.; Pinhasi, Ron; Stock, Jay T.

2016-01-01

Early life conditions play an important role in determining adult body size. In particular, childhood malnutrition and disease can elicit growth delays and affect adult body size if severe or prolonged enough. In the earliest stages of farming, skeletal growth impairment and small adult body size are often documented relative to hunter-gatherer groups, though this pattern is regionally variable. In Central/Southeast Europe, it is unclear how early life stress, growth history, and adult body size were impacted by the introduction of agriculture and ensuing long-term demographic, social, and behavioral change. The current study assesses this impact through the reconstruction and analysis of mean stature, body mass, limb proportion indices, and sexual dimorphism among 407 skeletally mature men and women from foraging and farming populations spanning the Late Mesolithic through Early Medieval periods in Central/Southeast Europe (~7100 calBC to 850 AD). Results document significantly reduced mean stature, body mass, and crural index in Neolithic agriculturalists relative both to Late Mesolithic hunter-gatherer-fishers and to later farming populations. This indication of relative growth impairment in the Neolithic, particularly among women, is supported by existing evidence of high developmental stress, intensive physical activity, and variable access to animal protein in these early agricultural populations. Among subsequent agriculturalists, temporal increases in mean stature, body mass, and crural index were more pronounced among Central European women, driving declines in the magnitude of sexual dimorphism through time. Overall, results suggest that the transition to agriculture in Central/Southeast Europe was challenging for early farming populations, but was followed by gradual amelioration across thousands of years, particularly among Central European women. This sex difference may be indicative, in part, of greater temporal variation in the social status afforded to young girls, in their access to resources during growth, and/or in their health status than was experienced by men. PMID:26844892

Correlated evolution of host and parasite body size: tests of Harrison's rule using birds and lice.

PubMed

Johnson, Kevin P; Bush, Sarah E; Clayton, Dale H

2005-08-01

Large-bodied species of hosts often harbor large-bodied parasites, a pattern known as Harrison's rule. Harrison's rule has been documented for a variety of animal parasites and herbivorous insects, yet the adaptive basis of the body-size correlation is poorly understood. We used phylogenetically independent methods to test for Harrison's rule across a large assemblage of bird lice (Insecta: Phthiraptera). The analysis revealed a significant relationship between louse and host size, despite considerable variation among taxa. We explored factors underlying this variation by testing Harrison's rule within two groups of feather-specialist lice that share hosts (pigeons and doves). The two groups, wing lice (Columbicola spp.) and body lice (Physconelloidinae spp.), have similar life histories, despite spending much of their time on different feather tracts. Wing lice showed strong support for Harrison's rule, whereas body lice showed no significant correlation with host size. Wing louse size was correlated with wing feather size, which was in turn correlated with overall host size. In contrast, body louse size showed no correlation with body feather size, which also was not correlated with overall host size. The reason why body lice did not fit Harrison's rule may be related to the fact that different species of body lice use different microhabitats within body feathers. More detailed measurements of body feathers may be needed to explore the precise relationship of body louse size to relevant components of feather size. Whatever the reason, Harrison's rule does not hold in body lice, possibly because selection on body size is mediated by community-level interactions between body lice.

Parallel effects of the inversion In(3R)Payne on body size across the North American and Australian clines in Drosophila melanogaster.

PubMed

Kapun, M; Schmidt, C; Durmaz, E; Schmidt, P S; Flatt, T

2016-05-01

Chromosomal inversions are thought to play a major role in climatic adaptation. In D. melanogaster, the cosmopolitan inversion In(3R)Payne exhibits latitudinal clines on multiple continents. As many fitness traits show similar clines, it is tempting to hypothesize that In(3R)P underlies observed clinal patterns for some of these traits. In support of this idea, previous work in Australian populations has demonstrated that In(3R)P affects body size but not development time or cold resistance. However, similar data from other clines of this inversion are largely lacking; finding parallel effects of In(3R)P across multiple clines would considerably strengthen the case for clinal selection. Here, we have analysed the phenotypic effects of In(3R)P in populations originating from the endpoints of the latitudinal cline along the North American east coast. We measured development time, egg-to-adult survival, several size-related traits (femur and tibia length, wing area and shape), chill coma recovery, oxidative stress resistance and triglyceride content in homokaryon lines carrying In(3R)P or the standard arrangement. Our central finding is that the effects of In(3R)P along the North American cline match those observed in Australia: standard arrangement lines were larger than inverted lines, but the inversion did not influence development time or cold resistance. Similarly, In(3R)P did not affect egg-to-adult survival, oxidative stress resistance and lipid content. In(3R)P thus seems to specifically affect size traits in populations from both continents. This parallelism strongly suggests an adaptive pattern, whereby the inversion has captured alleles associated with growth regulation and clinal selection acts on size across both continents. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Sexual Dimorphism of Body Size Is Controlled by Dosage of the X-Chromosomal Gene Myc and by the Sex-Determining Gene tra in Drosophila.

PubMed

Mathews, Kristina Wehr; Cavegn, Margrith; Zwicky, Monica

2017-03-01

Drosophila females are larger than males. In this article, we describe how X -chromosome dosage drives sexual dimorphism of body size through two means: first, through unbalanced expression of a key X -linked growth-regulating gene, and second, through female-specific activation of the sex-determination pathway. X -chromosome dosage determines phenotypic sex by regulating the genes of the sex-determining pathway. In the presence of two sets of X -chromosome signal elements (XSEs), Sex-lethal ( Sxl ) is activated in female ( XX ) but not male ( XY ) animals. Sxl activates transformer ( tra ), a gene that encodes a splicing factor essential for female-specific development. It has previously been shown that null mutations in the tra gene result in only a partial reduction of body size of XX animals, which shows that other factors must contribute to size determination. We tested whether X dosage directly affects animal size by analyzing males with duplications of X -chromosomal segments. Upon tiling across the X chromosome, we found four duplications that increase male size by >9%. Within these, we identified several genes that promote growth as a result of duplication. Only one of these, Myc , was found not to be dosage compensated. Together, our results indicate that both Myc dosage and tra expression play crucial roles in determining sex-specific size in Drosophila larvae and adult tissue. Since Myc also acts as an XSE that contributes to tra activation in early development, a double dose of Myc in females serves at least twice in development to promote sexual size dimorphism. Copyright © 2017 by the Genetics Society of America.

Optimal exploitation of spatially distributed trophic resources and population stability

USGS Publications Warehouse

Basset, A.; Fedele, M.; DeAngelis, D.L.

2002-01-01

The relationships between optimal foraging of individuals and population stability are addressed by testing, with a spatially explicit model, the effect of patch departure behaviour on individual energetics and population stability. A factorial experimental design was used to analyse the relevance of the behavioural factor in relation to three factors that are known to affect individual energetics; i.e. resource growth rate (RGR), assimilation efficiency (AE), and body size of individuals. The factorial combination of these factors produced 432 cases, and 1000 replicate simulations were run for each case. Net energy intake rates of the modelled consumers increased with increasing RGR, consumer AE, and consumer body size, as expected. Moreover, through their patch departure behaviour, by selecting the resource level at which they departed from the patch, individuals managed to substantially increase their net energy intake rates. Population stability was also affected by the behavioural factors and by the other factors, but with highly non-linear responses. Whenever resources were limiting for the consumers because of low RGR, large individual body size or low AE, population density at the equilibrium was directly related to the patch departure behaviour; on the other hand, optimal patch departure behaviour, which maximised the net energy intake at the individual level, had a negative influence on population stability whenever resource availability was high for the consumers. The consumer growth rate (r) and numerical dynamics, as well as the spatial and temporal fluctuations of resource density, which were the proximate causes of population stability or instability, were affected by the behavioural factor as strongly or even more strongly than by the others factors considered here. Therefore, patch departure behaviour can act as a feedback control of individual energetics, allowing consumers to optimise a potential trade-off between short-term individual fitness and long-term population stability. ?? 2002 Elsevier Science B.V. All rights reserved.

Estimation of body-size traits by photogrammetry in large mammals to inform conservation.

PubMed

Berger, Joel

2012-10-01

Photography, including remote imagery and camera traps, has contributed substantially to conservation. However, the potential to use photography to understand demography and inform policy is limited. To have practical value, remote assessments must be reasonably accurate and widely deployable. Prior efforts to develop noninvasive methods of estimating trait size have been motivated by a desire to answer evolutionary questions, measure physiological growth, or, in the case of illegal trade, assess economics of horn sizes; but rarely have such methods been directed at conservation. Here I demonstrate a simple, noninvasive photographic technique and address how knowledge of values of individual-specific metrics bears on conservation policy. I used 10 years of data on juvenile moose (Alces alces) to examine whether body size and probability of survival are positively correlated in cold climates. I investigated whether the presence of mothers improved juvenile survival. The posited latter relation is relevant to policy because harvest of adult females has been permitted in some Canadian and American jurisdictions under the assumption that probability of survival of young is independent of maternal presence. The accuracy of estimates of head sizes made from photographs exceeded 98%. The estimates revealed that overwinter juvenile survival had no relation to the juvenile's estimated mass (p < 0.64) and was more strongly associated with maternal presence (p < 0.02) than winter snow depth (p < 0.18). These findings highlight the effects on survival of a social dynamic (the mother-young association) rather than body size and suggest a change in harvest policy will increase survival. Furthermore, photographic imaging of growth of individual juvenile muskoxen (Ovibos moschatus) over 3 Arctic winters revealed annual variability in size, which supports the idea that noninvasive monitoring may allow one to detect how some environmental conditions ultimately affect body growth. ©2012 Society for Conservation Biology.

Mammal population regulation, keystone processes and ecosystem dynamics.

PubMed Central

Sinclair, A R E

2003-01-01

The theory of regulation in animal populations is fundamental to understanding the dynamics of populations, the causes of mortality and how natural selection shapes the life history of species. In mammals, the great range in body size allows us to see how allometric relationships affect the mode of regulation. Resource limitation is the fundamental cause of regulation. Top-down limitation through predators is determined by four factors: (i). body size; (ii). the diversity of predators and prey in the system; (iii). whether prey are resident or migratory; and (iv). the presence of alternative prey for predators. Body size in mammals has two important consequences. First, mammals, particularly large species, can act as keystones that determine the diversity of an ecosystem. I show how keystone processes can, in principle, be measured using the example of the wildebeest in the Serengeti ecosystem. Second, mammals act as ecological landscapers by altering vegetation succession. Mammals alter physical structure, ecological function and species diversity in most terrestrial biomes. In general, there is a close interaction between allometry, population regulation, life history and ecosystem dynamics. These relationships are relevant to applied aspects of conservation and pest management. PMID:14561329

On the relationship between ontogenetic and static allometry.

PubMed

Pélabon, Christophe; Bolstad, Geir H; Egset, Camilla K; Cheverud, James M; Pavlicev, Mihaela; Rosenqvist, Gunilla

2013-02-01

Ontogenetic and static allometries describe how a character changes in size when the size of the organism changes during ontogeny and among individuals measured at the same developmental stage, respectively. Understanding the relationship between these two types of allometry is crucial to understanding the evolution of allometry and, more generally, the evolution of shape. However, the effects of ontogenetic allometry on static allometry remain largely unexplored. Here, we first show analytically how individual variation in ontogenetic allometry and body size affect static allometry. Using two longitudinal data sets on ontogenetic and static allometry, we then estimate variances and covariances for the different parameters of the ontogenetic allometry defined in our model and assess their relative contribution to the static allometric slope. The mean ontogenetic allometry is the main parameter that determines the static allometric slope, while the covariance between the ontogenetic allometric slope and body size generates most of the discrepancies between ontogenetic and static allometry. These results suggest that the apparent evolutionary stasis of the static allometric slope is not generated by internal (developmental) constraints but more likely results from external constraints imposed by selection.

Genome-wide association studies identified multiple genetic loci for body size at four growth stages in Chinese Holstein cattle.

PubMed

Zhang, Xu; Chu, Qin; Guo, Gang; Dong, Ganghui; Li, Xizhi; Zhang, Qin; Zhang, Shengli; Zhang, Zhiwu; Wang, Yachun

2017-01-01

The growth and maturity of cattle body size affect not only feed efficiency, but also productivity and longevity. Dissecting the genetic architecture of body size is critical for cattle breeding to improve both efficiency and productivity. The volume and weight of body size are indicated by several measurements. Among them, Heart Girth (HG) and Hip Height (HH) are the most important traits. They are widely used as predictors of body weight (BW). Few association studies have been conducted for HG and HH in cattle focusing on single growth stage. In this study, we extended the Genome-wide association studies to a full spectrum of four growth stages (6-, 12-, 18-, and 24-months after birth) in Chinese Holstein heifers. The whole genomic single nucleotide polymorphisms (SNPs) were obtained from the Illumina BovineSNP50 v2 BeadChip genotyped on 3,325 individuals. Estimated breeding values (EBVs) were derived for both HG and HH at the four different ages and analyzed separately for GWAS by using the Fixed and random model Circuitous Probability Unification (FarmCPU) method. In total, 27 SNPs were identified to be significantly associated with HG and HH at different growth stages. We found 66 candidate genes located nearby the associated SNPs, including nine genes that were known as highly related to development and skeletal and muscular growth. In addition, biological function analysis was performed by Ingenuity Pathway Analysis and an interaction network related to development was obtained, which contained 16 genes out of the 66 candidates. The set of putative genes provided valuable resources and can help elucidate the genomic architecture and mechanisms underlying growth traits in dairy cattle.

Infection patterns of Paradollfusnema amphisbaenia (Nematoda: Cosmocercidae) in a population of Amphisbaena wuchereri (Squamata: Amphisbaenidae) from Minas Gerais state, south-eastern Brazil, and its relations with host size, sex and fat body mass.

PubMed

Filogonio, R; Toledo, G M; Anjos, L A; Rajão, B; Galdino, C A B; Nascimento, L B

2013-06-01

Specimens (n= 41) of the amphisbaenid Amphisbaena wuchereri taken from a population in Minas Gerais state, south-eastern Brazil, were examined for gastrointestinal parasites. A single nematode species was found, Paradollfusnema amphisbaenia. This was a new host record for this nematode species. This parasite was encountered in the large intestine (prevalence of 100%), in the stomach (prevalence of 2%) and in the small intestine (prevalence of 7.3%). The intensity of infection ranged from 1 to 457 individual parasites per host and was positively correlated with body size of both male and female amphisbaenians. The discrepancy index (D) indicated that P. amphisbaenia tended to an even distribution in this host population. The nematode, which did not affect fat body mass, induced inflammatory infiltrations in the small intestine, indicating that the parasites might injure the host's organs.

YORP effect on real objects. I. Statistical properties

NASA Astrophysics Data System (ADS)

Micheli, M.; Paolicchi, P.

2008-10-01

Context: The intensity of the YORP (Yarkovsky, O'Keefe, Radzievskii, and Paddack) effect and its ability to affect the rotational properties of asteroids depend mainly on the size of the body and on its shape. At present, we have a database of about 30 well-defined shapes of real minor bodies (most of them asteroids, but also planetary satellites and cometary nuclei). Aims: In this paper we perform a statistical analysis of how the YORP effect depends on the shape. Methods: We used the Rubincam approximation (i.e. neglecting the effects of a finite thermal conductivity). Results: We show that, among real bodies, the distribution of the YORP types, according to the classification of Vokrouhlický and Čapek, is significantly different from the one obtained in the same paper from theoretical modeling of shapes. A new “type” also comes out. Moreover, we show that the types are strongly correlated with the intensity of the YORP effect (when normalized to eliminate the dependence on the size, and thus only related to the shape).

Size matters: insights from an allometric approach to evaluate control methods for invasive Australian Rhinella marina.

PubMed

Beaty, Lynne E; Salice, Christopher J

2013-10-01

Invasive species are costly and difficult to control. In order to gain a mechanistic understanding of potential control measures, individual-based models uniquely parameterized to reflect the salient life-history characteristics of invasive species are useful. Using invasive Australian Rhinella marina as a case study, we constructed a cohort- and individual-based population simulation that incorporates growth and body size of terrestrial stages. We used this allometric approach to examine the efficacy of nontraditional control methods (i.e., tadpole alarm chemicals and native meat ants) that may have indirect effects on population dynamics mediated by effects on body size. We compared population estimates resulting from these control methods with traditional hand removal. We also conducted a sensitivity analysis to investigate the effect that model parameters, specifically those associated with growth and body size, had on adult population estimates. Incremental increases in hand removal of adults and juveniles caused nonlinear decreases in adult population estimates, suggesting less return with increased investment in hand-removal efforts. Applying tadpole alarm chemicals or meat ants decreased adult population estimates on the same level as removing 15-25% of adults and juveniles by hand. The combined application of tadpole alarm chemicals and meat ants resulted in approximately 80% decrease in adult abundance, the largest of any applied control method. In further support of the nontraditional control methods, which greatly affected the metamorph stage, our model was most sensitive to changes in metamorph survival, juvenile survival, metamorph growth rate, and adult survival. Our results highlight the use and insights that can be gained from individual-based models that incorporate growth and body size and the potential success that nontraditional control methods could have in controlling established, invasive Rhinella marina populations.

The roles of microclimatic diversity and of behavior in mediating the responses of ectotherms to climate change.

PubMed

Woods, H Arthur; Dillon, Michael E; Pincebourde, Sylvain

2015-12-01

We analyze the effects of changing patterns of thermal availability, in space and time, on the performance of small ectotherms. We approach this problem by breaking it into a series of smaller steps, focusing on: (1) how macroclimates interact with living and nonliving objects in the environment to produce a mosaic of thermal microclimates and (2) how mobile ectotherms filter those microclimates into realized body temperatures by moving around in them. Although the first step (generation of mosaics) is conceptually straightforward, there still exists no general framework for predicting spatial and temporal patterns of microclimatic variation. We organize potential variation along three axes-the nature of the objects producing the microclimates (abiotic versus biotic), how microclimates translate macroclimatic variation (amplify versus buffer), and the temporal and spatial scales over which microclimatic conditions vary (long versus short). From this organization, we propose several general rules about patterns of microclimatic diversity. To examine the second step (behavioral sampling of locally available microclimates), we construct a set of models that simulate ectotherms moving on a thermal landscape according to simple sets of diffusion-based rules. The models explore the effects of both changes in body size (which affect the time scale over which organisms integrate operative body temperatures) and increases in the mean and variance of temperature on the thermal landscape. Collectively, the models indicate that both simple behavioral rules and interactions between body size and spatial patterns of thermal variation can profoundly affect the distribution of realized body temperatures experienced by ectotherms. These analyses emphasize the rich set of problems still to solve before arriving at a general, predictive theory of the biological consequences of climate change. Copyright © 2014 Elsevier Ltd. All rights reserved.

Collisional Processing of Comet and Asteroid Surfaces: Velocity Effects on Absorption Spectra

NASA Technical Reports Server (NTRS)

Lederer, S. M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Smith, D. C.; Nakamura-Messenger, K.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

2012-01-01

A new paradigm has emerged where 3.9 Gyr ago, a violent reshuffling reshaped the placement of small bodies in the solar system (the Nice model). Surface properties of these objects may have been affected by collisions caused by this event, and by collisions with other small bodies since their emplacement. These impacts affect the spectrographic observations of these bodies today. Shock effects (e.g., planar dislocations) manifest in minerals allowing astronomers to better understand geophysical impact processing that has occurred on small bodies. At the Experimental Impact Laboratory at NASA Johnson Space Center, we have impacted forsterite and enstatite across a range of velocities. We find that the amount of spectral variation, absorption wavelength, and full width half maximum of the absorbance peaks vary non-linearly with the velocity of the impact. We also find that the spectral variation increases with decreasing crystal size (single solid rock versus granular). Future analyses include quantification of the spectral changes with different impactor densities, temperature, and additional impact velocities. Results on diopside, fayalite, and magnesite can be found in Lederer et al., this meeting.

Does Intraspecific Size Variation in a Predator Affect Its Diet Diversity and Top-Down Control of Prey?

PubMed Central

Ingram, Travis; Stutz, William E.; Bolnick, Daniel I.

2011-01-01

It has long been known that intraspecific variation impacts evolutionary processes, but only recently have its potential ecological effects received much attention. Theoretical models predict that genetic or phenotypic variance within species can alter interspecific interactions, and experiments have shown that genotypic diversity in clonal species can impact a wide range of ecological processes. To extend these studies to quantitative trait variation within populations, we experimentally manipulated the variance in body size of threespine stickleback in enclosures in a natural lake environment. We found that body size of stickleback in the lake is correlated with prey size and (to a lesser extent) composition, and that stickleback can exert top-down control on their benthic prey in enclosures. However, a six-fold contrast in body size variance had no effect on the degree of diet variation among individuals, or on the abundance or composition of benthic or pelagic prey. Interestingly, post-hoc analyses revealed suggestive correlations between the degree of diet variation and the strength of top-down control by stickleback. Our negative results indicate that, unless the correlation between morphology and diet is very strong, ecological variation among individuals may be largely decoupled from morphological variance. Consequently we should be cautious in our interpretation both of theoretical models that assume perfect correlations between morphology and diet, and of empirical studies that use morphological variation as a proxy for resource use diversity. PMID:21687670

Does intraspecific size variation in a predator affect its diet diversity and top-down control of prey?

PubMed

Ingram, Travis; Stutz, William E; Bolnick, Daniel I

2011-01-01

It has long been known that intraspecific variation impacts evolutionary processes, but only recently have its potential ecological effects received much attention. Theoretical models predict that genetic or phenotypic variance within species can alter interspecific interactions, and experiments have shown that genotypic diversity in clonal species can impact a wide range of ecological processes. To extend these studies to quantitative trait variation within populations, we experimentally manipulated the variance in body size of threespine stickleback in enclosures in a natural lake environment. We found that body size of stickleback in the lake is correlated with prey size and (to a lesser extent) composition, and that stickleback can exert top-down control on their benthic prey in enclosures. However, a six-fold contrast in body size variance had no effect on the degree of diet variation among individuals, or on the abundance or composition of benthic or pelagic prey. Interestingly, post-hoc analyses revealed suggestive correlations between the degree of diet variation and the strength of top-down control by stickleback. Our negative results indicate that, unless the correlation between morphology and diet is very strong, ecological variation among individuals may be largely decoupled from morphological variance. Consequently we should be cautious in our interpretation both of theoretical models that assume perfect correlations between morphology and diet, and of empirical studies that use morphological variation as a proxy for resource use diversity.

Foraging mode affects the evolution of egg size in generalist predators embedded in complex food webs.

PubMed

Verdeny-Vilalta, O; Fox, C W; Wise, D H; Moya-Laraño, J

2015-06-01

Ecological networks incorporate myriad biotic interactions that determine the selection pressures experienced by the embedded populations. We argue that within food webs, the negative scaling of abundance with body mass and foraging theory predict that the selective advantages of larger egg size should be smaller for sit-and-wait than active-hunting generalist predators, leading to the evolution of a difference in egg size between them. Because body mass usually scales negatively with predator abundance and constrains predation rate, slightly increasing egg mass should simultaneously allow offspring to feed on more prey and escape from more predators. However, the benefits of larger offspring would be relatively smaller for sit-and-wait predators because (i) due to their lower mobility, encounters with other predators are less common, and (ii) they usually employ a set of alternative hunting strategies that help to subdue relatively larger prey. On the other hand, for active predators, which need to confront prey as they find them, body-size differences may be more important in subduing prey. This difference in benefits should lead to the evolution of larger egg sizes in active-hunting relative to sit-and-wait predators. This prediction was confirmed by a phylogenetically controlled analysis of 268 spider species, supporting the view that the structure of ecological networks may serve to predict relevant selective pressures acting on key life history traits. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Which Measures of Obesity Are Related to Depressive Symptoms and in Whom?

PubMed Central

Lim, Weonjeong; Thomas, Kamala S.; Bardwell, Wayne A.; Dimsdale, Joel E.

2009-01-01

The authors asked which obesity measurements were associated with depressive symptoms, whether this relationship differed by gender, and whether controlling for fatigue and response bias affected the relationship. A sample of 129 subjects (66 men, 63 women), with a mean age of 36.9 years and a mean Body Mass Index (BMI) of 26.4 participated in the study. Depressive symptoms, levels of fatigue, response bias, and anthropometrics were assessed. In women, but not men, BMI and percent of ideal body weight were related to depression. However, percent of body fat did not show a relationship with depression after controlling for fatigue and response bias. These findings suggest that women’s depressive symptoms are more influenced by body size than body fat composition, whereas men’s depressive symptoms seem to be unrelated to obesity. PMID:18212172

Body size ideals and dissatisfaction in Ghanaian adolescents: role of media, lifestyle and well-being.

PubMed

Michels, N; Amenyah, S D

2017-05-01

To inspire effective health promotion campaigns, we tested the relationship of ideal body size and body size dissatisfaction with (1) the potential resulting health-influencing factors diet, physical activity and well-being; and (2) with media as a potential influencer of body ideals. This is a cross-sectional study in 370 Ghanaian adolescents (aged 11-18 years). Questionnaires included disordered eating (EAT26), diet quality (FFQ), physical activity (IPAQ), well-being (KINDL) and media influence on appearance (SATAQ: pressure, internalisation and information). Ideal body size and body size dissatisfaction were assessed using the Stunkard figure rating scale. Body mass index (BMI), skinfolds and waist were measured. Linear regressions were adjusted for gender, age and parental education. Also, mediation was tested: 'can perceived media influence play a role in the effects of actual body size on body size dissatisfaction?'. Body size dissatisfaction was associated with lower well-being and more media influence (pressure and internalisation) but not with physical activity, diet quality or disordered eating. An underweight body size ideal might worsen disordered eating but was not significantly related to the other predictors of interest. Only a partial mediation effect by media pressure was found: especially overweight adolescents felt media pressure, and this media pressure was associated with more body size dissatisfaction. To prevent disordered eating and low well-being, health messages should include strategies that reduce body size dissatisfaction and increase body esteem by not focussing on the thin body ideal. Changing body size ideals in the media might be an appropriate way since media pressure was a mediator in the BMI-dissatisfaction relation. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Fragmentation of nest and foraging habitat affects time budgets of solitary bees, their fitness and pollination services, depending on traits: Results from an individual-based model

PubMed Central

Settele, Josef; Dormann, Carsten F.

2018-01-01

Solitary bees are important but declining wild pollinators. During daily foraging in agricultural landscapes, they encounter a mosaic of patches with nest and foraging habitat and unsuitable matrix. It is insufficiently clear how spatial allocation of nesting and foraging resources and foraging traits of bees affect their daily foraging performance. We investigated potential brood cell construction (as proxy of fitness), number of visited flowers, foraging habitat visitation and foraging distance (pollination proxies) with the model SOLBEE (simulating pollen transport by solitary bees, tested and validated in an earlier study), for landscapes varying in landscape fragmentation and spatial allocation of nesting and foraging resources. Simulated bees varied in body size and nesting preference. We aimed to understand effects of landscape fragmentation and bee traits on bee fitness and the pollination services bees provide, as well as interactions between them, and the general consequences it has to our understanding of the system. This broad scope gives multiple key results. 1) Body size determines fitness more than landscape fragmentation, with large bees building fewer brood cells. High pollen requirements for large bees and the related high time budgets for visiting many flowers may not compensate for faster flight speeds and short handling times on flowers, giving them overall a disadvantage compared to small bees. 2) Nest preference does affect distribution of bees over the landscape, with cavity-nesting bees being restricted to nesting along field edges, which inevitably leads to performance reductions. Fragmentation mitigates this for cavity-nesting bees through increased edge habitat. 3) Landscape fragmentation alone had a relatively small effect on all responses. Instead, the local ratio of nest to foraging habitat affected bee fitness positively through reduced local competition. The spatial coverage of pollination increases steeply in response to this ratio for all bee sizes. The nest to foraging habitat ratio, a strong habitat proxy incorporating fragmentation could be a promising and practical measure for comparing landscape suitability for pollinators. 4) The number of flower visits was hardly affected by resource allocation, but predominantly by bee size. 5) In landscapes with the highest visitation coverage, bees flew least far, suggesting that these pollination proxies are subject to a trade-off between either longer pollen transport distances or a better pollination coverage, linked to how nests are distributed over the landscape rather than being affected by bee size. PMID:29444076

Fragmentation of nest and foraging habitat affects time budgets of solitary bees, their fitness and pollination services, depending on traits: Results from an individual-based model.

PubMed

Everaars, Jeroen; Settele, Josef; Dormann, Carsten F

2018-01-01

Solitary bees are important but declining wild pollinators. During daily foraging in agricultural landscapes, they encounter a mosaic of patches with nest and foraging habitat and unsuitable matrix. It is insufficiently clear how spatial allocation of nesting and foraging resources and foraging traits of bees affect their daily foraging performance. We investigated potential brood cell construction (as proxy of fitness), number of visited flowers, foraging habitat visitation and foraging distance (pollination proxies) with the model SOLBEE (simulating pollen transport by solitary bees, tested and validated in an earlier study), for landscapes varying in landscape fragmentation and spatial allocation of nesting and foraging resources. Simulated bees varied in body size and nesting preference. We aimed to understand effects of landscape fragmentation and bee traits on bee fitness and the pollination services bees provide, as well as interactions between them, and the general consequences it has to our understanding of the system. This broad scope gives multiple key results. 1) Body size determines fitness more than landscape fragmentation, with large bees building fewer brood cells. High pollen requirements for large bees and the related high time budgets for visiting many flowers may not compensate for faster flight speeds and short handling times on flowers, giving them overall a disadvantage compared to small bees. 2) Nest preference does affect distribution of bees over the landscape, with cavity-nesting bees being restricted to nesting along field edges, which inevitably leads to performance reductions. Fragmentation mitigates this for cavity-nesting bees through increased edge habitat. 3) Landscape fragmentation alone had a relatively small effect on all responses. Instead, the local ratio of nest to foraging habitat affected bee fitness positively through reduced local competition. The spatial coverage of pollination increases steeply in response to this ratio for all bee sizes. The nest to foraging habitat ratio, a strong habitat proxy incorporating fragmentation could be a promising and practical measure for comparing landscape suitability for pollinators. 4) The number of flower visits was hardly affected by resource allocation, but predominantly by bee size. 5) In landscapes with the highest visitation coverage, bees flew least far, suggesting that these pollination proxies are subject to a trade-off between either longer pollen transport distances or a better pollination coverage, linked to how nests are distributed over the landscape rather than being affected by bee size.

Beyond size–number trade-offs: clutch size as a maternal effect

PubMed Central

Brown, Gregory P.; Shine, Richard

2009-01-01

Traditionally, research on life-history traits has viewed the link between clutch size and offspring size as a straightforward linear trade-off; the product of these two components is taken as a measure of maternal reproductive output. Investing more per egg results in fewer but larger eggs and, hence, offspring. This simple size–number trade-off has proved attractive to modellers, but our experimental studies on keelback snakes (Tropidonophis mairii, Colubridae) reveal a more complex relationship between clutch size and offspring size. At constant water availability, the amount of water taken up by a snake egg depends upon the number of adjacent eggs. In turn, water uptake affects hatchling size, and therefore an increase in clutch size directly increases offspring size (and thus fitness under field conditions). This allometric advantage may influence the evolution of reproductive traits such as growth versus reproductive effort, optimal age at female maturation, the body-reserve threshold required to initiate reproduction and nest-site selection (e.g. communal oviposition). The published literature suggests that similar kinds of complex effects of clutch size on offspring viability are widespread in both vertebrates and invertebrates. Our results also challenge conventional experimental methodologies such as split-clutch designs for laboratory incubation studies: by separating an egg from its siblings, we may directly affect offspring size and thus viability. PMID:19324614

Spatial and temporal structure of a mesocarnivore guild in midwestern north America

Treesearch

Damon B. Lesmeister; Clayton K. Nielsen; Eric M. Schauber; Eric C. Hellgren

2015-01-01

Carnivore guilds play a vital role in ecological communities by cascading trophic effects, energy and nutrient transfer, and stabilizing or destabilizing food webs. Consequently, the structure of carnivore guilds can be critical to ecosystem patterns. Body size is a crucial influence on intraguild interactions, because it affects access to prey resources, effectiveness...

The effects of body exposure on self-body image and esthetic appreciation in anorexia nervosa.

PubMed

Cazzato, Valentina; Mian, Emanuel; Mele, Sonia; Tognana, Giulia; Todisco, Patrizia; Urgesi, Cosimo

2016-03-01

Repeated exposures to thin-idealized body shapes may alter women's perceptions of what normal (e.g., accepted) and ideal (e.g., desired) bodies in a cultural environment look like. The aim of the present study was to investigate whether exposure to thin and round body shapes may change the subsequent esthetic appreciation of others' bodies and the perceptual and cognitive-affective dimensions of self-body image in patients suffering from anorexia nervosa (AN). Thirteen AN patients and 13 matched healthy controls were exposed to pictures of either thin or round unfamiliar body models and, before and after exposure, they were required to either express liking judgments about round and slim figures of unfamiliar bodies (esthetic task) or to adjust distorted pictures of their own body to their perceptual (How do you see yourself?), affective (How do you feel yourself?), metacognitive (How do others see you?) and ideal (How would you like to look like?) body image (self-body adjustment task). Brief exposures to round models increased liking judgments of round figures in both groups. However, only in AN patients, exposure to round models induced an increase in thin figures liking, which positively correlated with their preoccupation with dieting. Furthermore, exposure to round bodies in AN patients, but not in controls, increased the distortion for the perceptual body image and decreased the size of the ideal one. No differences between the two groups were obtained after adaptation to thin models. Our results suggest that AN patients' perception of their own and others' body is more easily malleable by exposure to round figures as compared to controls. Crucially, this mechanism may strongly contribute to the development and maintenance of self-body image disturbances.

Low is large: spatial location and pitch interact in voice-based body size estimation.

PubMed

Pisanski, Katarzyna; Isenstein, Sari G E; Montano, Kelyn J; O'Connor, Jillian J M; Feinberg, David R

2017-05-01

The binding of incongruent cues poses a challenge for multimodal perception. Indeed, although taller objects emit sounds from higher elevations, low-pitched sounds are perceptually mapped both to large size and to low elevation. In the present study, we examined how these incongruent vertical spatial cues (up is more) and pitch cues (low is large) to size interact, and whether similar biases influence size perception along the horizontal axis. In Experiment 1, we measured listeners' voice-based judgments of human body size using pitch-manipulated voices projected from a high versus a low, and a right versus a left, spatial location. Listeners associated low spatial locations with largeness for lowered-pitch but not for raised-pitch voices, demonstrating that pitch overrode vertical-elevation cues. Listeners associated rightward spatial locations with largeness, regardless of voice pitch. In Experiment 2, listeners performed the task while sitting or standing, allowing us to examine self-referential cues to elevation in size estimation. Listeners associated vertically low and rightward spatial cues with largeness more for lowered- than for raised-pitch voices. These correspondences were robust to sex (of both the voice and the listener) and head elevation (standing or sitting); however, horizontal correspondences were amplified when participants stood. Moreover, when participants were standing, their judgments of how much larger men's voices sounded than women's increased when the voices were projected from the low speaker. Our results provide novel evidence for a multidimensional spatial mapping of pitch that is generalizable to human voices and that affects performance in an indirect, ecologically relevant spatial task (body size estimation). These findings suggest that crossmodal pitch correspondences evoke both low-level and higher-level cognitive processes.

The relationship between mammal faunas and climatic instability since the Last Glacial Maximum: A Nearctic vs. Western Palearctic comparison

NASA Astrophysics Data System (ADS)

Torres-Romero, Erik Joaquín; Varela, Sara; Fisher, Jason T.; Olalla-Tárraga, Miguel Á.

2017-07-01

Climate has played a key role in shaping the geographic patterns of biodiversity. The imprint of Quaternary climatic fluctuations is particularly evident on the geographic distribution of Holarctic faunas, which dramatically shifted their ranges following the alternation of glacial-interglacial cycles during the Pleistocene. Here, we evaluate the existence of differences between climatically stable and unstable regions - defined on the basis of climatic change velocity since the Last Glacial Maximum - in the geographic distribution of several biological attributes of extant terrestrial mammals of the Nearctic and Western Palearctic regions. Specifically, we use a macroecological approach to assess the dissimilarities in species richness, range size, body size, longevity and litter size of species that inhabit regions with contrasting histories of climatic stability. While several studies have documented how the distributional ranges of animals can be affected by long-term historic climatic fluctuations, there is less evidence on the species-specific traits that determine their responsiveness under such climatic instability. We find that climatically unstable areas have more widespread species and lower mammal richness than stable regions in both continents. We detected stronger signatures of historical climatic instability on the geographic distribution of body size in the Nearctic region, possibly reflecting lagged responses to recolonize deglaciated regions. However, the way that animals respond to climatic fluctuations varies widely among species and we were unable to find a relationship between climatic instability and other mammal life-history traits (longevity and litter size) in any of the two biogeographic regions. We, therefore, conclude that beyond some biological traits typical of macroecological analyses such as geographic range size and body size, it is difficult to infer the responsiveness of species distributions to climate change solely based on particular life-history traits.

The role of life histories and trophic interactions in population recovery.

PubMed

Audzijonyte, Asta; Kuparinen, Anna

2016-08-01

Factors affecting population recovery from depletion are at the focus of wildlife management. Particularly, it has been debated how life-history characteristics might affect population recovery ability and productivity. Many exploited fish stocks have shown temporal changes towards earlier maturation and reduced adult body size, potentially owing to evolutionary responses to fishing. Whereas such life-history changes have been widely documented, their potential role on stock's ability to recover from exploitation often remains ignored by traditional fisheries management. We used a marine ecosystem model parameterized for Southeastern Australian ecosystem to explore how changes towards "faster" life histories might affect population per capita growth rate r. We show that for most species changes towards earlier maturation during fishing have a negative effect (3-40% decrease) on r during the recovery phase. Faster juvenile growth and earlier maturation were beneficial early in life, but smaller adult body sizes reduced the lifetime reproductive output and increased adult natural mortality. However, both at intra- and inter-specific level natural mortality and trophic position of the species were as important in determining r as species longevity and age of maturation, suggesting that r cannot be predicted from life-history traits alone. Our study highlights that factors affecting population recovery ability and productivity should be explored in a multi-species context, where both age-specific fecundity and survival schedules are addressed simultaneously. It also suggests that contemporary life-history changes in harvested species are unlikely to increase their resilience and recovery ability. © 2016 Society for Conservation Biology.

Exteroceptive and Interoceptive Body-Self Awareness in Fibromyalgia Patients

PubMed Central

Valenzuela-Moguillansky, Camila; Reyes-Reyes, Alejandro; Gaete, María I.

2017-01-01

Fibromyalgia is a widespread chronic pain disease characterized by generalized musculoskeletal pain and fatigue. It substantially affects patients' relationship with their bodies and quality of life, but few studies have investigated the relationship between pain and body awareness in fibromyalgia. We examined exteroceptive and interoceptive aspects of body awareness in 30 women with fibromyalgia and 29 control participants. Exteroceptive body awareness was assessed by a body-scaled action-anticipation task in which participants estimated whether they could pass through apertures of different widths. Interoceptive sensitivity (IS) was assessed by a heartbeat detection task where participants counted their heartbeats during different time intervals. Interoceptive awareness was assessed by the Multidimensional Assessment of Interoceptive Awareness (MAIA). The “passability ratio” (the aperture size for a 50% positive response rate, divided by shoulder width), assessed by the body-scaled action-anticipation task, was higher for fibromyalgia participants, indicating disrupted exteroceptive awareness. Overestimating body size correlated positively with pain and its impact on functionality, but not with pain intensity. There was no difference in IS between groups. Fibromyalgia patients exhibited a higher tendency to note bodily sensations and decreased body confidence. In addition, the passability ratio and IS score correlated negatively across the whole sample, suggesting an inverse relationship between exteroceptive and interoceptive body awareness. There was a lower tendency to actively listen to the body for insight, with higher passability ratios across the whole sample. Based on our results and building on the fear-avoidance model, we outline a proposal that highlights possible interactions between exteroceptive and interoceptive body awareness and pain. Movement based contemplative practices that target sensory-motor integration and foster non-judgmental reconnection with bodily sensations are suggested to improve body confidence, functionality, and quality of life. PMID:28348526

Exteroceptive and Interoceptive Body-Self Awareness in Fibromyalgia Patients.

PubMed

Valenzuela-Moguillansky, Camila; Reyes-Reyes, Alejandro; Gaete, María I

2017-01-01

Fibromyalgia is a widespread chronic pain disease characterized by generalized musculoskeletal pain and fatigue. It substantially affects patients' relationship with their bodies and quality of life, but few studies have investigated the relationship between pain and body awareness in fibromyalgia. We examined exteroceptive and interoceptive aspects of body awareness in 30 women with fibromyalgia and 29 control participants. Exteroceptive body awareness was assessed by a body-scaled action-anticipation task in which participants estimated whether they could pass through apertures of different widths. Interoceptive sensitivity (IS) was assessed by a heartbeat detection task where participants counted their heartbeats during different time intervals. Interoceptive awareness was assessed by the Multidimensional Assessment of Interoceptive Awareness (MAIA). The "passability ratio" (the aperture size for a 50% positive response rate, divided by shoulder width), assessed by the body-scaled action-anticipation task, was higher for fibromyalgia participants, indicating disrupted exteroceptive awareness. Overestimating body size correlated positively with pain and its impact on functionality, but not with pain intensity. There was no difference in IS between groups. Fibromyalgia patients exhibited a higher tendency to note bodily sensations and decreased body confidence. In addition, the passability ratio and IS score correlated negatively across the whole sample, suggesting an inverse relationship between exteroceptive and interoceptive body awareness. There was a lower tendency to actively listen to the body for insight, with higher passability ratios across the whole sample. Based on our results and building on the fear-avoidance model, we outline a proposal that highlights possible interactions between exteroceptive and interoceptive body awareness and pain. Movement based contemplative practices that target sensory-motor integration and foster non-judgmental reconnection with bodily sensations are suggested to improve body confidence, functionality, and quality of life.

The discovery of silicon oxide nanoparticles in space-weathered of Apollo 15 lunar soil grains

NASA Astrophysics Data System (ADS)

Gu, Lixin; Zhang, Bin; Hu, Sen; Noguchi, Takaaki; Hidaka, Hiroshi; Lin, Yangting

2018-03-01

Space weathering is an important process on the Moon and other airless celestial bodies. The most common space weathering effects are amorphization of the top surface of soil grains and formation of nanophase iron particles (npFe) within the partially amorphous rims. Hence, space weathering significantly affects optical properties of the surface of the Moon and other airless celestial bodies. Transmission electron microscope (TEM) analysis of Apollo 15 soil grains displays npFe (≤5 nm in size) embedded in the space-weathered rim (∼60 nm in thickness) of a pyroxene grain, consistent with previous studies. In contrast, submicron-sized fragments that adhere to the pyroxene grain show distinct space weathering features. Silicon oxide nanoparticles (npSiOx) were observed with npFe in a submicron-sized Mg-Fe silicate fragment. This is the first discovery of npSiOx as a product of space weathering. The npSiOx and the coexisting npFe are ∼10-25 nm in size, significantly larger than the typical npFe in the space weathered rim of the pyroxene grain. The coexisting npSiOx and npFe were probably formed directly in micrometeorite shock-induced melt, instead of in a solar-wind generated vapor deposit or irradiated rim. This new observation will shed light on space weathering processes on the Moon and airless celestial bodies.

Illusions of having small or large invisible bodies influence visual perception of object size

PubMed Central

van der Hoort, Björn; Ehrsson, H. Henrik

2016-01-01

The size of our body influences the perceived size of the world so that objects appear larger to children than to adults. The mechanisms underlying this effect remain unclear. It has been difficult to dissociate visual rescaling of the external environment based on an individual’s visible body from visual rescaling based on a central multisensory body representation. To differentiate these potential causal mechanisms, we manipulated body representation without a visible body by taking advantage of recent developments in body representation research. Participants experienced the illusion of having a small or large invisible body while object-size perception was tested. Our findings show that the perceived size of test-objects was determined by the size of the invisible body (inverse relation), and by the strength of the invisible body illusion. These findings demonstrate how central body representation directly influences visual size perception, without the need for a visible body, by rescaling the spatial representation of the environment. PMID:27708344

Bite force estimation and the fiber architecture of felid masticatory muscles.

PubMed

Hartstone-Rose, Adam; Perry, Jonathan M G; Morrow, Caroline J

2012-08-01

Increasingly, analyses of craniodental dietary adaptations take into account mechanical properties of foods. However, masticatory muscle fiber architecture has been described for relatively few lineages, even though an understanding of the scaling of this anatomy can yield important information about adaptations for stretch and strength in the masticatory system. Data on the mandibular adductors of 28 specimens from nine species of felids representing nearly the entire body size range of the family allow us to evaluate the influence of body size and diet on the masticatory apparatus within this lineage. Masticatory muscle masses scale isometrically, tending toward positive allometry, with body mass and jaw length. This allometry becomes significant when the independent variable is a geometric mean of cranial variables. For all three body size proxies, the physiological cross-sectional area and predicted bite forces scale with significant positive allometry. Average fiber lengths (FL) tend toward negative allometry though with wide confidence intervals resulting from substantial scatter. We believe that these FL residuals are affected by dietary signals within the sample; though the mechanical properties of felid diets are relatively similar across species, the most durophagous species in our sample (the jaguar) appears to have relatively higher force production capabilities. The more notable dietary trend in our sample is the relationship between FL and relative prey size: felid species that predominantly consume relatively small prey have short masticatory muscle fibers, and species that regularly consume relatively large prey have relatively long fibers. This suggests an adaptive signal related to gape. Copyright © 2012 Wiley Periodicals, Inc.

Body Size, Fecundity, and Sexual Size Dimorphism in the Neotropical Cricket Macroanaxipha macilenta (Saussure) (Orthoptera: Gryllidae).

PubMed

Cueva Del Castillo, R

2015-04-01

Body size is directly or indirectly correlated with fitness. Body size, which conveys maximal fitness, often differs between sexes. Sexual size dimorphism (SSD) evolves because body size tends to be related to reproductive success through different pathways in males and females. In general, female insects are larger than males, suggesting that natural selection for high female fecundity could be stronger than sexual selection in males. I assessed the role of body size and fecundity in SSD in the Neotropical cricket Macroanaxipha macilenta (Saussure). This species shows a SSD bias toward males. Females did not present a correlation between number of eggs and body size. Nonetheless, there were fluctuations in the number of eggs carried by females during the sampling period, and the size of females that were collected carrying eggs was larger than that of females collected with no eggs. Since mating induces vitellogenesis in some cricket species, differences in female body size might suggest male mate choice. Sexual selection in the body size of males of M. macilenta may possibly be stronger than the selection of female fecundity. Even so, no mating behavior was observed during the field observations, including audible male calling or courtship songs, yet males may produce ultrasonic calls due to their size. If female body size in M. macilenta is not directly related to fecundity, the lack of a correlated response to selection on female body size could represent an alternate evolutionary pathway in the evolution of body size and SSD in insects.

Is the interspecific variation of body size of land snails correlated with rainfall in Israel and Palestine?

NASA Astrophysics Data System (ADS)

Hausdorf, Bernhard

2006-11-01

The hypothesis that body size of land snail species increases with aridity in Israel and Palestine because large snails lose relatively less water due to their lower surface to volume ratio has been investigated. Data on rainfall amplitudes of 84 land snail species in Israel and Palestine and on their body sizes were used to test for interspecific correlations between body size and rainfall. Four methods, means of body sizes in rainfall categories, the midpoint method, the across-species method, and a phylogenetically controlled analysis (CAIC) showed that there is no significant correlation between body size of land snail species and their rainfall amplitude in Israel and Palestine. The lack of an interspecific correlation between body size and rainfall amplitude may be the result of conflicting selective forces on body size.

Garment sizes in perception of body size.

PubMed

Fan, Jintu; Newton, Edward; Lau, Lilian; Liu, Fu

2003-06-01

This paper reports an experimental investigation of the effect of garment size on perceived body size. The perceived body sizes of three Chinese men (thin, medium, and obese build) wearing different sizes of white T-shirts were assessed using Thompson and Gray's 1995 Nine-figural Scale in 1 (thinnest) to 9 (obese) grade and a newly-proposed method. Within the limit of commercially available T-shirt sizes, for thin and medium persons, perceived body sizes are bigger when wearing T-shirts of larger sizes. For an obese person, however, wearing a large size T-shirt tends to make him look thinner. The study also showed that the newly proposed comparative method is more reliable in comparing body size perception but without measuring the magnitude of the change in body-size grade. The figural scale and the comparative method can be complementary.

Surgical Removal of a Ventricular Foreign Body in a Captive African Black-footed Penguin ( Spheniscus demersus ).

PubMed

Castaño-Jiménez, Paula A; Trent, Ava M; Bueno, Irene

2016-03-01

Anterior gastrointestinal tract obstruction by a foreign body has been reported in several avian species, most commonly in captive birds. It is often associated with behavioral issues that lead to compulsive consumption of bedding materials or bright moving objects. In penguins, foreign bodies are most commonly identified at necropsy and often are found in the ventriculus because of anatomic characteristics of the species. A captive African black-footed penguin ( Spheniscus demersus ) was diagnosed with a ventricular foreign body. The anatomic and physiologic differences that should be taken into account when surgically removing a ventricular foreign body in a penguin are described. These differences include the caudal location in the coelom and the large size of the ventriculus in proportion to the penguin's body size; the presence of a simple stomach, uniform in thickness and lacking muscular development; a simple gastrointestinal cycle (gastric contraction); and variability in pH of stomach contents. No complications were observed after surgery, and the bird recovered completely. Management of foreign bodies in birds should be based on the clinical signs of the individual bird, the species affected and its anatomic characteristics, the nature and location of the foreign body, available tools, and the preference and experience of the surgeon. This particular case demonstrates that the most indicated and preferred method is not always possible and that knowledge of biologic, anatomic, and physiologic differences of the species may allow the use of an alternative and more invasive approach with favorable outcomes.

Plio-Pleistocene extinctions and immigration credit reflected in the size-frequency distribution of Mediterranean marine bivalves

NASA Astrophysics Data System (ADS)

Nawrot, Rafal; Zuschin, Martin; Chattopadhyay, Devapriya

2015-04-01

Following the opening of the Suez Canal hundreds of Red Sea species have entered the Mediterranean Sea making it a global hot spot of marine bioinvasion. With the ongoing influx of the subtropical and tropical alien species and increasing sea surface temperatures, the Mediterranean biota is currently gaining a more tropical character and increasingly becoming a mixture of faunal stocks with different evolutionary histories. This susceptibility to invasion was suggested to reflect the presence of an empty ecological space left after decimation of incumbent warm-water fauna during Plio-Pleistocene climate fluctuations. As molluscs are among the most prolific immigrants, we test this hypothesis using data on taxonomic composition and body size of Pliocene Mediterranean bivalves derived from the literature sources and museum collections. The Pliocene inter-specific size-frequency distribution (SFD) is strikingly similar to the SFDs of the Recent Red Sea bivalve fauna, in spite of different biogeographic provenance and the absence of true reef ecosystems in the Pliocene of the Mediterranean region. In contrast, body-size patterns in both assemblages are significantly different from the present-day Mediterranean fauna characterized by smaller median and modal size. Our preliminary results suggest that the distinct shape of the modern Mediterranean SFD may reflect the selective nature of the late Piacenzian - Galesian (Late Pliocene - Early Pleistocene) extinctions pulses related to the onset of the Northern Hemisphere glaciations. These extinctions affected almost 40% of Pliocene species and were biased towards large-bodied taxa. They were not followed by re-immigration of warm-water species owing to the isolation from the tropical Atlantic biota by the cold upwelling along the NW coasts of Africa. The resulting invasion credit (sensu Jackson & Sax, 2010) is currently being paid by the Red Sea bivalves colonizing the Mediterranean Sea through the Suez Canal. Successful immigrants are significantly larger than native species reflecting the gross differences in the body-size distributions of the source and recipient species pools. These size differences are further amplified by environmental and biotic filters acting along the invasion pathway. Therefore, the continuing inflow of tropical invaders will restore the Pliocene body-size patterns in the Mediterranean bivalve fauna. References Jackson, S.T. & Sax, D.F., 2010. Trends in Ecology and Evolution, 25: 153-160

Factors affecting aggressive behaviour of spawning migratory males towards mature male parr in masu salmon Oncorhynchus masou.

PubMed

Watanabe, M; Maekawa, K

2010-07-01

This study examined whether dominant migratory males (adopting fighter tactics) of the masu salmon Oncorhynchus masou would more aggressively attack large mature male parr (adopting sneaker tactics) as large mature male parr are expected to have the potential to cause a greater decrease in fertilization success. The frequency of aggressive behaviour was not related to the body size of males, and it increased with the frequency of interactions with mature male parr. The fertilization success of mature male parr was much lower than migratory males, and no relationship was observed between fertilization success and aggressive behaviour. The low fertilization success of mature male parr, despite infrequent aggressive behaviour by migratory males, indicates that there might be little benefit for migratory males to attack mature male parr more aggressively according to their body size.

Body condition explains migratory performance of a long-distance migrant.

PubMed

Duijns, Sjoerd; Niles, Lawrence J; Dey, Amanda; Aubry, Yves; Friis, Christian; Koch, Stephanie; Anderson, Alexandra M; Smith, Paul A

2017-11-15

Body condition (i.e. relative mass after correcting for structural size) affects the behaviour of migrating birds, but how body condition affects migratory performance, timing and fitness is still largely unknown. Here, we studied the effects of relative body condition on individual departure decisions, wind selectivity, flight speed and timing of migration for a long-distance migratory shorebird, the red knot Calidris canutus rufa. By using automated VHF telemetry on a continental scale, we studied knots' migratory movements with unprecedented temporal resolution over a 3-year period. Knots with a higher relative body condition left the staging site later than birds in lower condition, yet still arrived earlier to their Arctic breeding grounds compared to knots in lower relative body condition. They accomplished this by selecting more favourable winds at departure, thereby flying faster and making shorter stops en route Individuals with a higher relative body condition in spring migrated south up to a month later than individuals in lower condition, suggesting that individuals in better condition were more likely to have bred successfully. Moreover, individuals with a lower relative body condition in spring had a lower probability of being detected in autumn, suggestive of increased mortality. The pressure to arrive early to the breeding grounds is considered to be an important constraint of migratory behaviour and this study highlights the important influence of body condition on migratory decisions, performance and potentially fitness of migrant birds. © 2017 The Authors.

Effects of age and body mass index on breast characteristics: A cluster analysis.

PubMed

Coltman, Celeste E; Steele, Julie R; McGhee, Deirdre E

2018-05-24

Limited research has quantified variation in the characteristics of the breasts among women and determined how these breast characteristics are influenced by age and body mass. The aim of this study was to classify the breasts of women in the community into different categories based on comprehensive and objective measurements of the characteristics of their breasts and torsos, and to determine the effect of age and body mass index (BMI) on the prevalence of these breast categories. Four breast characteristic clusters were identified (X-Large, Very-ptotic & Splayed; Large, Ptotic & Splayed; Medium & Mildly-ptotic; and Small & Non-ptotic), with age and BMI shown to significantly affect the breast characteristic clusters. These results highlight the difference in breast characteristics exhibited among women and how these clusters are affected by age and BMI. The breast characteristic clusters identified in this study could be used as a basis for future bra designs and sizing systems in order to improve bra fit for women.

Eco-evolution in size-structured ecosystems: simulation case study of rapid morphological changes in alewife.

PubMed

Kang, Jung Koo; Thibert-Plante, Xavier

2017-02-27

Over the last 300 years, interactions between alewives and zooplankton communities in several lakes in the U.S. have caused the alewives' morphology to transition rapidly from anadromous to landlocked. Lakes with landlocked alewives contain smaller-bodied zooplankton than those without alewives. Landlocked adult alewives display smaller body sizes, narrower gapes, smaller inter-gill-raker spacings, reach maturity at an earlier age, and are less fecund than anadromous alewives. Additionally, landlocked alewives consume pelagic prey exclusively throughout their lives whereas anadromous alewives make an ontogenetic transition from pelagic to littoral prey. These rapid, well-documented changes in the alewives' morphology provide important insights into the morphological evolution of fish. Predicting the morphological evolution of fish is crucial for fisheries and ecosystem management, but the involvement of multiple trophic interactions make predictions difficult. To obtain an improved understanding of rapid morphological change in fish, we developed an individual-based model that simulated rapid changes in the body size and gill-raker count of a fish species in a hypothetical, size-structured prey community. Model parameter values were based mainly on data from empirical studies on alewives. We adopted a functional trait approach; consequently, the model explicitly describes the relationships between prey body size, alewife body size, and alewife gill-raker count. We sought to answer two questions: (1) How does the impact of alewife populations on prey feed back to impact alewife size and gill raker number under several alternative scenarios? (2) Will the trajectory of the landlocked alewives' morphological evolution change after 150-300 years in freshwater? Over the first 250 years, the alewives' numbers of gill-rakers only increased when reductions in their body size substantially improved their ability to forage for small prey. Additionally, alewives' gill-raker counts increased more rapidly as the adverse effects of narrow gill-raker spacings on foraging for large prey were made less severe. For the first 150-250 years, alewives' growth decreased monotonically, and their gill-raker number increased monotonically. After the first 150-250 years, however, the alewives exhibited multiple evolutionary morphological trajectories in different trophic settings. In several of these settings, their evolutionary trajectories even reversed after the first 150-250 years. Alewives affected the abundance and morphology of their prey, which in turn changed the abundance and morphology of the alewives. Complex low-trophic-level interactions can alter the abundance and characteristics of alewives. This study suggests that the current morphology of recently (∼300 years)-landlocked alewives may not represent an evolutionarily stable state.

Influence of male morphology on male mating status and behavior during interunit encounters in western lowland gorillas.

PubMed

Caillaud, Damien; Levréro, Florence; Gatti, Sylvain; Ménard, Nelly; Raymond, Michel

2008-04-01

The western lowland gorilla (Gorilla gorilla gorilla) is one of the most sexually dimorphic primate species. Mature males are twice the size of females and have grey fur on their backs and a fibrous, adipose crest on their heads. Such traits are likely to have evolved by sexual selection, either because they confer advantages during male-male fights or because females prefer males with more dimorphic traits. We developed photogrammetric methods for distance collection of morphological data from silverback males frequenting the Lokoué forest clearing in Odzala-Kokoua National Park, Republic of the Congo. Body length, head-crest size, musculature development, and extent of the grey color on the back were assessed in 87 nonbreeding and breeding mature males. Behavioral data were also collected during 312 male-male encounters involving 67 mature males in order to estimate their level of aggressiveness. The number of females belonging to a mature male positively correlated with the male crest size, body length, and musculature. Whereas morphological variables did not significantly affect the intensity of male-male encounters, the number of females attending male-male encounters strongly affected the number of agonistic displays by the two males. We discuss the mechanisms through which males with more exaggerated traits could obtain a mating advantage, namely male-male fights or female mate choice. (c) 2007 Wiley-Liss, Inc.

Pelvic dimorphism in relation to body size and body size dimorphism in humans.

PubMed

Kurki, Helen K

2011-12-01

Many mammalian species display sexual dimorphism in the pelvis, where females possess larger dimensions of the obstetric (pelvic) canal than males. This is contrary to the general pattern of body size dimorphism, where males are larger than females. Pelvic dimorphism is often attributed to selection relating to parturition, or as a developmental consequence of secondary sexual differentiation (different allometric growth trajectories of each sex). Among anthropoid primates, species with higher body size dimorphism have higher pelvic dimorphism (in converse directions), which is consistent with an explanation of differential growth trajectories for pelvic dimorphism. This study investigates whether the pattern holds intraspecifically in humans by asking: Do human populations with high body size dimorphism also display high pelvic dimorphism? Previous research demonstrated that in some small-bodied populations, relative pelvic canal size can be larger than in large-bodied populations, while others have suggested that larger-bodied human populations display greater body size dimorphism. Eleven human skeletal samples (total N: male = 229, female = 208) were utilized, representing a range of body sizes and geographical regions. Skeletal measurements of the pelvis and femur were collected and indices of sexual dimorphism for the pelvis and femur were calculated for each sample [ln(M/F)]. Linear regression was used to examine the relationships between indices of pelvic and femoral size dimorphism, and between pelvic dimorphism and female femoral size. Contrary to expectations, the results suggest that pelvic dimorphism in humans is generally not correlated with body size dimorphism or female body size. These results indicate that divergent patterns of dimorphism exist for the pelvis and body size in humans. Implications for the evaluation of the evolution of pelvic dimorphism and rotational childbirth in Homo are considered. Copyright © 2011 Elsevier Ltd. All rights reserved.

Methodological considerations for analyzing trabecular architecture: an example from the primate hand.

PubMed

Kivell, Tracy L; Skinner, Matthew M; Lazenby, Richard; Hublin, Jean-Jacques

2011-02-01

Micro-computed tomographic analyses of trabecular bone architecture have been used to clarify the link between positional behavior and skeletal anatomy in primates. However, there are methodological decisions associated with quantifying and comparing trabecular anatomy across taxa that vary greatly in body size and morphology that can affect characterizations of trabecular architecture, such as choice of the volume of interest (VOI) size and location. The potential effects of these decisions may be amplified in small, irregular-shaped bones of the hands and feet that have more complex external morphology and more heterogeneous trabecular structure compared to, for example, the spherical epiphysis of the femoral head. In this study we investigate the effects of changes in VOI size and location on standard trabecular parameters in two bones of the hand, the capitate and third metacarpal, in a diverse sample of nonhuman primates that vary greatly in morphology, body mass and positional behavior. Results demonstrate that changes in VOI location and, to a lesser extent, changes in VOI size had a dramatic affect on many trabecular parameters, especially trabecular connectivity and structure (rods vs. plates), degree of anisotropy, and the primary orientation of the trabeculae. Although previous research has shown that some trabecular parameters are susceptible to slight variations in methodology (e.g. VOI location, scan resolution), this study provides a quantification of these effects in hand bones of a diverse sample of primates. An a priori understanding of the inherent biases created by the choice of VOI size and particularly location is critical to robust trabecular analysis and functional interpretation, especially in small bones with complex arthroses. © 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.

[Variability patterns of nest construction, physiological state, and morphometric traits in honey bee].

PubMed

Es'kov, E K; Es'kova, M D

2014-01-01

High variability of cells size is used selectively for reproduction of working bees and drones. A decrease in both distance between cells and cells size themselves causes similar effects to body mass and morphometric traits of developing individuals. Adaptation of honey bees to living in shelters has led to their becoming tolerant to hypoxia. Improvement of ethological and physiological mechanisms of thermal regulation is associated with limitation of ecological valence and acquiring of stenothermic features by breed. Optimal thermal conditions for breed are limited by the interval 33-34.5 degrees C. Deviations of temperature by 3-4 degrees C beyond this range have minimum lethal effect at embryonic stage of development and medium effect at the stage of pre-pupa and pupa. Developing at the low bound of the vital range leads to increasing, while developing at the upper bound--to decreasing of body mass, mandibular and hypopharyngeal glands, as well as other organs, which, later, affects the variability of these traits during the adult stage of development. Eliminative and teratogenic efficiency of ecological factors that affect a breed is most often manifested in underdevelopment of wings. However, their size (in case of wing laminas formation). is characterized by relatively low variability and size-dependent asymmetry. Asymmetry variability of wings and other pair organs is expressed through realignment of size excess from right- to left-side one with respect to their increase. Selective elimination by those traits whose emerging probability increases as developmental conditions deviate from the optimal ones promotes restrictions on individual variability. Physiological mechanisms that facilitate adaptability enhancement under conditions of increasing anthropogenic contamination of eivironment and trophic substrates consumed by honey bees, arrear to be toxicants accumulation in rectum and crops' ability to absorb contaminants from nectar in course of its processing to honey.

The effects of density dependent resource limitation on size of wild reindeer.

PubMed

Skogland, Terje

1983-11-01

A density-dependent decrement in size for wild reindeer from 12 different Norwegian herds at 16 different densities was shown using lower jawbone-length as the criterion of size. This criterion was tested and found to adequately predict body size of both bucks and does. Lactation in does did not affect jaw length but significantly affected dressed weights.A decrement in the size of does as a result of gross density was found. This size decrement was further analysed in relation to the habitat densities in winter (R 2 =0.85) and in summer (R 2 =0.75) separately, in order to estimate the relative effects of each factor. For herds with adequate food in winter (no signs of overgrazing of lichens) density in relation to summer habitat and mires yielded the highest predictive power in a multiple regression. For herds with adequate summer pastures, densities per winter habitat and lichen volumes showed likewise a highly significant correlation. The inclusion of the lichen volume data in the regression increased its predictive power. The major effect of resource limitation was to delay the time of calving because a maternal carry-over effect allowed the calf a shorter period of growth to be completed during its first summer. Neonate size at birth was highly correlated with maternal size regardless of the mean calving date although the latter was significantly delayed for small-sized does in food resource-limited herds. Likewise the postnatal growth rate of all calves were not significantly different during 50 days postpartum regardless of maternal conditions in winter feeding. The summer growth rates of bucks ≧1 year did not vary significantly between herds. The age of maturity of food resource-limited does was delayed by one year and growth ceased after the initiation of reproduction. This shows that under conditions of limited resources the does with delayed births of calves allocated less energy to body growth simply because they had less time to replenish body reserves once they were freed of the energetic demands of lactation. The overriding effects of such limitation of food resources is thus to produce a time-lag for the completition of all the important life-history events, such as growth, maintenance and reproduction. From a theoretical point of view, i.e. according to the reproductive effort model their only option is to try to overcome this time limitation to reproductive success.

Characterization of fibropapillomatosis in green turtles Chelonia mydas (Cheloniidae) captured in a foraging area in southeastern Brazil.

PubMed

Tagliolatto, Alícia Bertoloto; Guimarães, Suzana Machado; Lobo-Hajdu, Gisele; Monteiro-Neto, Cassiano

2016-10-27

Fibropapillomatosis (FP) is a multifactorial disease that affects all species of marine turtles, including green turtles Chelonia mydas (Linnaeus, 1758). It is characterised by the development of internal or external tumours that, depending on their locations and sizes, may intensely impact the health condition of sea turtles. The goal of this study was to characterise the disease in C. mydas found in a foraging area in southeastern Brazil, evaluate the prevalence in this region, and correlate presence and absence, size, body distribution, number of tumours, and disease severity with biometric variables of the captured green turtles. Between 2008 and 2014, the prevalence rate of FP was 43.09%, out of 246 green turtles. The size of the animals with FP was relatively greater than animals without tumours, and the prevalence of FP increased with animal size, peaking in the 60-80 cm size class. From 2013 to 2014, gross evaluation of fibropapillomas was performed. The number of tumours per turtle ranged from 1 to 158. The size of tumours ranged from <1 cm (Size A) to >10 cm (Size D); Size A tumours and turtles slightly affected by the disease (Score 1) predominated. Tumour progression (72.1%) and regression (32.8%) were seen in some recaptured individuals (n = 61). Moreover, 24.6% of these turtles showed both progressions and regressions of tumours.

The effects of overwintering and habitat type on body condition and locomotion of the wolf spider Pardosa alacris

NASA Astrophysics Data System (ADS)

Ingle, Kapilkumar; Horváth, Ádám; Gallé-Szpisjak, Nikolett; Gellért, Levente; Csata, Enikő; Gallé, Róbert

2018-05-01

Overwintering in temperate regions is a prominent mortality risk for invertebrates and may affect their behaviour and body condition. Pardosa alacris is a common ground dwelling spider in central European native and plantation forests, and habitat type and prey availability may play important roles in their overwintering. The effect of overwintering on body condition and behaviour of spiders in semi natural and exotic habitats is relatively unknown. Here we assess the effects of winter on spiders from native poplar and exotic pine plantations. The locomotory behaviour of P. alacris (distance covered and speed) was assessed by tracking their movement in a white circular plastic arena. We assessed body condition, body size, and total fat content. Forest type and sex had significant effects on body length. Fat content was significantly higher in the spring than in autumn, and spiders covered larger distances and were faster in autumn than in spring. Fat content had a significant negative effect on average speed. Spiders in native forests were smaller but grew more during the winter than in exotic plantations, possibly due to higher prey availability in native forests. Visually-hunting predators may significantly affect spiders. Fat spiders with better body condition moved less, and were thus less detectable by predators. However the low movement rate may result in a low rate of encountering prey items, thus lowering feeding efficiency.

Fixation patterns, not clinical diagnosis, predict body size over-estimation in eating disordered women and healthy controls.

PubMed

Cornelissen, Katri K; Cornelissen, Piers L; Hancock, Peter J B; Tovée, Martin J

2016-05-01

A core feature of anorexia nervosa (AN) is an over-estimation of body size. Women with AN have a different pattern of eye-movements when judging bodies, but it is unclear whether this is specific to their diagnosis or whether it is found in anyone over-estimating body size. To address this question, we compared the eye movement patterns from three participant groups while they carried out a body size estimation task: (i) 20 women with recovering/recovered anorexia (rAN) who had concerns about body shape and weight and who over-estimated body size, (ii) 20 healthy controls who had normative levels of concern about body shape and who estimated body size accurately (iii) 20 healthy controls who had normative levels of concern about body shape but who did over-estimate body size. Comparisons between the three groups showed that: (i) accurate body size estimators tended to look more in the waist region, and this was independent of clinical diagnosis; (ii) there is a pattern of looking at images of bodies, particularly viewing the upper parts of the torso and face, which is specific to participants with rAN but which is independent of accuracy in body size estimation. Since the over-estimating controls did not share the same body image concerns that women with rAN report, their over-estimation cannot be explained by attitudinal concerns about body shape and weight. These results suggest that a distributed fixation pattern is associated with over-estimation of body size and should be addressed in treatment programs. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:507-518). © 2016 The Authors. International Journal of Eating Disorders published by Wiley Periodicals, Inc.

Nonplantigrade Foot Posture: A Constraint on Dinosaur Body Size

PubMed Central

Kubo, Tai; Kubo, Mugino O.

2016-01-01

Dinosaurs had functionally digitigrade or sub-unguligrade foot postures. With their immediate ancestors, dinosaurs were the only terrestrial nonplantigrades during the Mesozoic. Extant terrestrial mammals have different optimal body sizes according to their foot posture (plantigrade, digitigrade, and unguligrade), yet the relationship of nonplantigrade foot posture with dinosaur body size has never been investigated, even though the body size of dinosaurs has been studied intensively. According to a large dataset presented in this study, the body sizes of all nonplantigrades (including nonvolant dinosaurs, nonvolant terrestrial birds, extant mammals, and extinct Nearctic mammals) are above 500 g, except for macroscelid mammals (i.e., elephant shrew), a few alvarezsauroid dinosaurs, and nondinosaur ornithodirans (i.e., the immediate ancestors of dinosaurs). When nonplantigrade tetrapods evolved from plantigrade ancestors, lineages with nonplantigrade foot posture exhibited a steady increase in body size following Cope’s rule. In contrast, contemporaneous plantigrade lineages exhibited no trend in body size evolution and were largely constrained to small body sizes. This evolutionary pattern of body size specific to foot posture occurred repeatedly during both the Mesozoic and the Cenozoic eras. Although disturbed by the end-Cretaceous extinction, species of mid to large body size have predominantly been nonplantigrade animals from the Jurassic until the present; conversely, species with small body size have been exclusively composed of plantigrades in the nonvolant terrestrial tetrapod fauna. PMID:26790003

Nonplantigrade Foot Posture: A Constraint on Dinosaur Body Size.

PubMed

Kubo, Tai; Kubo, Mugino O

2016-01-01

Dinosaurs had functionally digitigrade or sub-unguligrade foot postures. With their immediate ancestors, dinosaurs were the only terrestrial nonplantigrades during the Mesozoic. Extant terrestrial mammals have different optimal body sizes according to their foot posture (plantigrade, digitigrade, and unguligrade), yet the relationship of nonplantigrade foot posture with dinosaur body size has never been investigated, even though the body size of dinosaurs has been studied intensively. According to a large dataset presented in this study, the body sizes of all nonplantigrades (including nonvolant dinosaurs, nonvolant terrestrial birds, extant mammals, and extinct Nearctic mammals) are above 500 g, except for macroscelid mammals (i.e., elephant shrew), a few alvarezsauroid dinosaurs, and nondinosaur ornithodirans (i.e., the immediate ancestors of dinosaurs). When nonplantigrade tetrapods evolved from plantigrade ancestors, lineages with nonplantigrade foot posture exhibited a steady increase in body size following Cope's rule. In contrast, contemporaneous plantigrade lineages exhibited no trend in body size evolution and were largely constrained to small body sizes. This evolutionary pattern of body size specific to foot posture occurred repeatedly during both the Mesozoic and the Cenozoic eras. Although disturbed by the end-Cretaceous extinction, species of mid to large body size have predominantly been nonplantigrade animals from the Jurassic until the present; conversely, species with small body size have been exclusively composed of plantigrades in the nonvolant terrestrial tetrapod fauna.

Investigating Young Children's Perceptions of Body Size and Healthy Habits

ERIC Educational Resources Information Center

Xu, Tingting; Nerren, Jannah S.

2017-01-01

Attitudes and biases toward body size perceived as fat and body size perceived as thin are present in young children (Cramer and Steinwert in "J Appl Dev Psychol" 19(3):429-451, 1998; Worobey and Worobey in "Body Image" 11:171-174, 2014). However, the information children have regarding body size and ways to modify body size…

Spatial and temporal variation of body size among early Homo.

PubMed

Will, Manuel; Stock, Jay T

2015-05-01

The estimation of body size among the earliest members of the genus Homo (2.4-1.5Myr [millions of years ago]) is central to interpretations of their biology. It is widely accepted that Homo ergaster possessed increased body size compared with Homo habilis and Homo rudolfensis, and that this may have been a factor involved with the dispersal of Homo out of Africa. The study of taxonomic differences in body size, however, is problematic. Postcranial remains are rarely associated with craniodental fossils, and taxonomic attributions frequently rest upon the size of skeletal elements. Previous body size estimates have been based upon well-preserved specimens with a more reliable species assessment. Since these samples are small (n < 5) and disparate in space and time, little is known about geographical and chronological variation in body size within early Homo. We investigate temporal and spatial variation in body size among fossils of early Homo using a 'taxon-free' approach, considering evidence for size variation from isolated and fragmentary postcranial remains (n = 39). To render the size of disparate fossil elements comparable, we derived new regression equations for common parameters of body size from a globally representative sample of hunter-gatherers and applied them to available postcranial measurements from the fossils. The results demonstrate chronological and spatial variation but no simple temporal or geographical trends for the evolution of body size among early Homo. Pronounced body size increases within Africa take place only after hominin populations were established at Dmanisi, suggesting that migrations into Eurasia were not contingent on larger body sizes. The primary evidence for these marked changes among early Homo is based upon material from Koobi Fora after 1.7Myr, indicating regional size variation. The significant body size differences between specimens from Koobi Fora and Olduvai support the cranial evidence for at least two co-existing morphotypes in the Early Pleistocene of eastern Africa. Copyright © 2015 Elsevier Ltd. All rights reserved.

The evolution of island gigantism and body size variation in tortoises and turtles

PubMed Central

Jaffe, Alexander L.; Slater, Graham J.; Alfaro, Michael E.

2011-01-01

Extant chelonians (turtles and tortoises) span almost four orders of magnitude of body size, including the startling examples of gigantism seen in the tortoises of the Galapagos and Seychelles islands. However, the evolutionary determinants of size diversity in chelonians are poorly understood. We present a comparative analysis of body size evolution in turtles and tortoises within a phylogenetic framework. Our results reveal a pronounced relationship between habitat and optimal body size in chelonians. We found strong evidence for separate, larger optimal body sizes for sea turtles and island tortoises, the latter showing support for the rule of island gigantism in non-mammalian amniotes. Optimal sizes for freshwater and mainland terrestrial turtles are similar and smaller, although the range of body size variation in these forms is qualitatively greater. The greater number of potential niches in freshwater and terrestrial environments may mean that body size relationships are more complicated in these habitats. PMID:21270022

Insights into bioassessment of marine pollution using body-size distinctness of planktonic ciliates based on a modified trait hierarchy.

PubMed

Xu, Henglong; Jiang, Yong; Xu, Guangjian

2016-06-15

Based on a modified trait hierarchy of body-size units, the feasibility for bioassessment of water pollution using body-size distinctness of planktonic ciliates was studied in a semi-enclosed bay, northern China. An annual dataset was collected at five sampling stations within a gradient of heavy metal contaminants. Results showed that: (1) in terms of probability density, the body-size spectra of the ciliates represented significant differences among the five stations; (2) bootstrap average analysis demonstrated a spatial variation in body-size rank patterns in response to pollution stress due to heavy metals; and (3) the average body-size distinctness (Δz(+)) and variation in body-size distinctness (Λz(+)), based on the modified trait hierarchy, revealed a clear departure pattern from the expected body-size spectra in areas with pollutants. These results suggest that the body-size diversity measures based on the modified trait hierarchy of the ciliates may be used as a potential indicator of marine pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Obesity and Body Size Preferences of Jordanian Women

ERIC Educational Resources Information Center

Madanat, Hala; Hawks, Steven R.; Angeles, Heidi N.

2011-01-01

The nutrition transition is associated with increased obesity rates and increased desire to be thin. This study evaluates the relationship between actual body size and desired body size among a representative sample of 800 Jordanian women. Using Stunkard's body silhouettes, women were asked to identify their current and ideal body sizes, healthy…

Decreases in beetle body size linked to climate change and warming temperatures.

PubMed

Tseng, Michelle; Kaur, Katrina M; Soleimani Pari, Sina; Sarai, Karnjit; Chan, Denessa; Yao, Christine H; Porto, Paula; Toor, Anmol; Toor, Harpawantaj S; Fograscher, Katrina

2018-05-01

Body size is a fundamental ecological trait and is correlated with population dynamics, community structure and function, and ecosystem fluxes. Laboratory data from broad taxonomic groups suggest that a widespread response to a warming world may be an overall decrease in organism body size. However, given the myriad of biotic and abiotic factors that can also influence organism body size in the wild, it is unclear whether results from these laboratory assays hold in nature. Here we use datasets spanning 30 to 100 years to examine whether the body size of wild-caught beetles has changed over time, whether body size changes are correlated with increased temperatures, and we frame these results using predictions derived from a quantitative review of laboratory responses of 22 beetle species to temperature. We found that 95% of laboratory-reared beetles decreased in size with increased rearing temperature, with larger-bodied species shrinking disproportionately more than smaller-bodied beetles. In addition, the museum datasets revealed that larger-bodied beetle species have decreased in size over time, that mean beetle body size explains much of the interspecific variation in beetle responses to temperature, and that long-term beetle size changes are explained by increases in autumn temperature and decreases in spring temperature in this region. Our data demonstrate that the relationship between body size and temperature of wild-caught beetles matches relatively well with results from laboratory studies, and that variation in this relationship is largely explained by interspecific variation in mean beetle body size. This long-term beetle dataset is one of the most comprehensive arthropod body size datasets compiled to date, it improves predictions regarding the shrinking of organisms with global climate change, and together with the meta-analysis data, call for new hypotheses to explain why larger-bodied organisms may be more sensitive to temperature. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.

Effects of excess salt and fat intake on myocardial function and infarct size in rat.

PubMed

Mozaffari, Mahmood S; Patel, Champa; Ballas, Claudia; Schaffer, Stephen W

2006-03-13

Important risk factors for cardiovascular disease include excess dietary intake of saturated fat and (or) salt. This study tested the hypothesis that excess intakes of saturated fat (e.g., beef tallow) and salt cause greater myocardial cell death following ischemia-reperfusion injury than each risk factor alone. Male rats were divided into four groups: basal fat diet (4.5% as calories; control), high fat diet (40% as calories; FAT), basal fat diet and high salt (1% NaCl solution; SALT) and high fat diet and high salt (FATSALT). The gain in body weight was significantly higher for FAT and FATSALT groups than those of either the control or the SALT group. Five weeks of exposure to the dietary regimens did not significantly affect the coronary flow rate and except for the salt-fed group, had no effect on the rate-pressure-product of the isolated heart perfused in Langendorff mode. Although infarct size was not affected by the high fat diet, it was reduced by the high salt regimen relative to the high fat diet or the control groups. When rats were fed the FAT and SALT combination, the effect of salt feeding on infarct size was not observed. In addition, the FATSALT group displayed a more marked deterioration in contractile function following ischemia-reperfusion injury than the other groups. In conclusion, short-term intake of a high fat diet, which significantly increases body weight, does not worsen ischemia-reperfusion injury although the treatment prevents the reduction of infarct size associated with high salt feeding.

Climate change affects low trophic level marine consumers: warming decreases copepod size and abundance.

PubMed

Garzke, Jessica; Ismar, Stefanie M H; Sommer, Ulrich

2015-03-01

Concern about climate change has re-ignited interest in universal ecological responses to temperature variations: (1) biogeographical shifts, (2) phenology changes, and (3) size shifts. In this study we used copepods as model organisms to study size responses to temperature because of their central role in the pelagic food web and because of the ontogenetic length constancy between molts, which facilitates the definition of size of distinct developmental stages. In order to test the expected temperature-induced shifts towards smaller body size and lower abundances under warming conditions, a mesocosm experiment using plankton from the Baltic Sea at three temperature levels (ambient, ambient +4 °C, ambient -4 °C) was performed in summer 2010. Overall copepod and copepodit abundances, copepod size at all life stages, and adult copepod size in particular, showed significant temperature effects. As expected, zooplankton peak abundance was lower in warm than in ambient treatments. Copepod size-at-immature stage significantly increased in cold treatments, while adult size significantly decreased in warm treatments.

The hunt for a functional mutation affecting conformation and calving traits on chromosome 18 in Holstein cattle

USDA-ARS?s Scientific Manuscript database

Sequence data from 11 US Holstein bulls were analyzed to identify putative causal mutations associated with calving and conformation traits. The SNP ARS-BFGL-NGS-109285 at 57,589,121 bp (UMD 3.1 assembly) on BTA18 has large effects on 4 measures of body shape and size, 2 measures of dystocia, longev...

Body size of Chrysomelidae (Coleoptera, Insecta) in areas with different levels of conservation in South Brazil

PubMed Central

Linzmeier, Adelita M.; Ribeiro-Costa, Cibele S.

2011-01-01

Abstract Body size is correlated with many species traits such as morphology, physiology, life history and abundance as well; it is one of the most discussed topics in macroecological studies. The aim of this paper was to analyze the body size distribution of Chrysomelidae, caught with Malaise traps during two years in four areas with different levels of conservation in the Araucaria Forest, Paraná, Brazil, determining if body size is a good predictor of abundance, and if body size could be used to indicate environmental quality. Body size was considered the total length of the specimen from the anterior region of head to the apex of abdomen/elytron. Measurements were taken for up to ten specimens of each species for each area and for all specimens of those species represented by fewer than ten individuals. The highest abundance and richness of Chrysomelidae were obtained in the lowest body size classes. This herbivorous group showed a trend toward a decrease in body size with increasing abundance, but body size was not a good predictor of its abundance. There was a trend toward a decrease in body size from the less to the most conserved areas; however, the definition of a pattern in successional areas not seems to be entirely clear. PMID:22303100

Global biogeography and ecology of body size in birds.

PubMed

Olson, Valérie A; Davies, Richard G; Orme, C David L; Thomas, Gavin H; Meiri, Shai; Blackburn, Tim M; Gaston, Kevin J; Owens, Ian P F; Bennett, Peter M

2009-03-01

In 1847, Karl Bergmann proposed that temperature gradients are the key to understanding geographic variation in the body sizes of warm-blooded animals. Yet both the geographic patterns of body-size variation and their underlying mechanisms remain controversial. Here, we conduct the first assemblage-level global examination of 'Bergmann's rule' within an entire animal class. We generate global maps of avian body size and demonstrate a general pattern of larger body sizes at high latitudes, conforming to Bergmann's rule. We also show, however, that median body size within assemblages is systematically large on islands and small in species-rich areas. Similarly, while spatial models show that temperature is the single strongest environmental correlate of body size, there are secondary correlations with resource availability and a strong pattern of decreasing body size with increasing species richness. Finally, our results suggest that geographic patterns of body size are caused both by adaptation within lineages, as invoked by Bergmann, and by taxonomic turnover among lineages. Taken together, these results indicate that while Bergmann's prediction based on physiological scaling is remarkably accurate, it is far from the full picture. Global patterns of body size in avian assemblages are driven by interactions between the physiological demands of the environment, resource availability, species richness and taxonomic turnover among lineages.

Factor Affecting Transplant Outcomes in Diabetic Nude Mice Receiving Human, Porcine, and Non-Human Primate Islets: Analysis of 335 Transplantations

PubMed Central

Loganathan, Gopalakrishnan; Graham, Melanie L.; Radosevich, David M.; Soltani, Sajjad M.; Tiwari, Mukesh; Anazawa, Takayuki; papas, Klearchos K.; Sutherland, David E.R.; Hering, Bernhard J.; Balamurugan, A.N.

2013-01-01

Background In the absence of a reliable islet potency assay, nude mice transplant is the criterion standard to assess islet quality for clinical transplantation. There are factors other than islet quality that affect the transplant outcome. Methods Here, we analyzed the transplant outcomes in 335 nude mice (NM) receiving islets from human (n=103), porcine (n=205), and non-human primate (NHP) donors (n=27). The islets (750, 1000, and 2000 islet equivalents) were transplanted under the kidney capsule of streptozotocin (STZ) induced diabetic NM. Results The proportion of mice that achieved normoglycemia was significantly higher in the group implanted with 2000 IEQ of human, porcine, or NHP islets (75% normoglycemic) versus groups that were implanted with 750 IEQ (7% normoglycemic) and 1000 IEQ (30% normoglycemic). In this study, we observed that the purity of porcine islet preparations (P ≤ .001), islet pellet size in porcine preparations (P ≤ .01) and mice recipient body weight for human islets preparations (P =.013), was independently associated with successful transplant outcome. NHP islets of 1000 IEQ were sufficient to achieve normoglycemic condition (83%). An islet mass of 2000 IEQ, high islet purity, increased recipient body weight, and high islet pellet volume increased the likelihood of successful reversal of diabetes in transplanted mice. Also, higher insulin secretory status of islets at basal stimulus was associated with a reduced mouse cure rate. The cumulative incidence of graft failure was significantly greater in human islets (56.12%) compared with porcine islets 35.57% (P ≤ .001). Conclusion Factors affecting NM bioassay were identified (islet mass, islet purity, pellet size, in vitro insulin secretory capability and mouse recipient body weight) and should be considered when evaluating islet function. PMID:23677052

Heat stress but not inbreeding affects offensive sperm competitiveness in Callosobruchus maculatus

PubMed Central

Lieshout, Emile; Tomkins, Joseph L; Simmons, Leigh W

2013-01-01

Environmental and genetic stress have well-known detrimental effects on ejaculate quality, but their concomitant effect on male fitness remains poorly understood. We used competitive fertilization assays to expose the effects of stress on offensive sperm competitive ability in the beetle Callosobruchus maculatus, a species where ejaculates make up more than 5% of male body mass. To examine the effects of environmental and genetic stress, males derived from outcrosses or sib matings were heat shocked at 50°C for 50 min during the pupal stage, while their siblings were maintained at a standard rearing temperature of 28°C. Heat-shocked males achieved only half the offensive paternity success of their siblings. While this population exhibited inbreeding depression in body size, sperm competitiveness was unaffected by inbreeding, nor did the effect of heat shock stress on sperm competitiveness depend on inbreeding status. In contrast, pupal emergence success was increased by 34% among heat-stressed individuals, regardless of their inbreeding status. Heat-shocked males' ejaculate size was 19% reduced, but they exhibited 25% increased mating duration in single mating trials. Our results highlight both the importance of stress in postcopulatory sexual selection, and the variability among stressors in affecting male fitness. PMID:24101978

Evidence of Bos javanicus x Bos indicus hybridization and major QTLs for birth weight in Indonesian Peranakan Ongole cattle.

PubMed

Hartati, Hartati; Utsunomiya, Yuri Tani; Sonstegard, Tad Stewart; Garcia, José Fernando; Jakaria, Jakaria; Muladno, Muladno

2015-07-04

Peranakan Ongole (PO) is a major Indonesian Bos indicus breed that derives from animals imported from India in the late 19(th) century. Early imports were followed by hybridization with the Bos javanicus subspecies of cattle. Here, we used genomic data to partition the ancestry components of PO cattle and map loci implicated in birth weight. We found that B. javanicus contributes about 6-7% to the average breed composition of PO cattle. Only two nearly fixed B. javanicus haplotypes were identified, suggesting that most of the B. javanicus variants are segregating under drift or by the action of balancing selection. The zebu component of the PO genome was estimated to derive from at least two distinct ancestral pools. Additionally, well-known loci underlying body size in other beef cattle breeds, such as the PLAG1 region on chromosome 14, were found to also affect birth weight in PO cattle. This study is the first attempt to characterize PO at the genome level, and contributes evidence of successful, stabilized B. indicus x B. javanicus hybridization. Additionally, previously described loci implicated in body size in worldwide beef cattle breeds also affect birth weight in PO cattle.

Heat stress but not inbreeding affects offensive sperm competitiveness in Callosobruchus maculatus.

PubMed

Lieshout, Emile; Tomkins, Joseph L; Simmons, Leigh W

2013-09-01

Environmental and genetic stress have well-known detrimental effects on ejaculate quality, but their concomitant effect on male fitness remains poorly understood. We used competitive fertilization assays to expose the effects of stress on offensive sperm competitive ability in the beetle Callosobruchus maculatus, a species where ejaculates make up more than 5% of male body mass. To examine the effects of environmental and genetic stress, males derived from outcrosses or sib matings were heat shocked at 50°C for 50 min during the pupal stage, while their siblings were maintained at a standard rearing temperature of 28°C. Heat-shocked males achieved only half the offensive paternity success of their siblings. While this population exhibited inbreeding depression in body size, sperm competitiveness was unaffected by inbreeding, nor did the effect of heat shock stress on sperm competitiveness depend on inbreeding status. In contrast, pupal emergence success was increased by 34% among heat-stressed individuals, regardless of their inbreeding status. Heat-shocked males' ejaculate size was 19% reduced, but they exhibited 25% increased mating duration in single mating trials. Our results highlight both the importance of stress in postcopulatory sexual selection, and the variability among stressors in affecting male fitness.

Mammal body size evolution in North America and Europe over 20 Myr: similar trends generated by different processes.

PubMed

Huang, Shan; Eronen, Jussi T; Janis, Christine M; Saarinen, Juha J; Silvestro, Daniele; Fritz, Susanne A

2017-02-22

Because body size interacts with many fundamental biological properties of a species, body size evolution can be an essential component of the generation and maintenance of biodiversity. Here we investigate how body size evolution can be linked to the clade-specific diversification dynamics in different geographical regions. We analyse an extensive body size dataset of Neogene large herbivores (covering approx. 50% of the 970 species in the orders Artiodactyla and Perissodactyla) in Europe and North America in a Bayesian framework. We reconstruct the temporal patterns of body size in each order on each continent independently, and find significant increases of minimum size in three of the continental assemblages (except European perissodactyls), suggesting an active selection for larger bodies. Assessment of trait-correlated birth-death models indicates that the common trend of body size increase is generated by different processes in different clades and regions. Larger-bodied artiodactyl species on both continents tend to have higher origination rates, and both clades in North America show strong links between large bodies and low extinction rate. Collectively, our results suggest a strong role of species selection and perhaps of higher-taxon sorting in driving body size evolution, and highlight the value of investigating evolutionary processes in a biogeographic context. © 2017 The Author(s).

Mammal body size evolution in North America and Europe over 20 Myr: similar trends generated by different processes

PubMed Central

Eronen, Jussi T.; Janis, Christine M.; Saarinen, Juha J.

2017-01-01

Because body size interacts with many fundamental biological properties of a species, body size evolution can be an essential component of the generation and maintenance of biodiversity. Here we investigate how body size evolution can be linked to the clade-specific diversification dynamics in different geographical regions. We analyse an extensive body size dataset of Neogene large herbivores (covering approx. 50% of the 970 species in the orders Artiodactyla and Perissodactyla) in Europe and North America in a Bayesian framework. We reconstruct the temporal patterns of body size in each order on each continent independently, and find significant increases of minimum size in three of the continental assemblages (except European perissodactyls), suggesting an active selection for larger bodies. Assessment of trait-correlated birth-death models indicates that the common trend of body size increase is generated by different processes in different clades and regions. Larger-bodied artiodactyl species on both continents tend to have higher origination rates, and both clades in North America show strong links between large bodies and low extinction rate. Collectively, our results suggest a strong role of species selection and perhaps of higher-taxon sorting in driving body size evolution, and highlight the value of investigating evolutionary processes in a biogeographic context. PMID:28202809

Owning an overweight or underweight body: distinguishing the physical, experienced and virtual body.

PubMed

Piryankova, Ivelina V; Wong, Hong Yu; Linkenauger, Sally A; Stinson, Catherine; Longo, Matthew R; Bülthoff, Heinrich H; Mohler, Betty J

2014-01-01

Our bodies are the most intimately familiar objects we encounter in our perceptual environment. Virtual reality provides a unique method to allow us to experience having a very different body from our own, thereby providing a valuable method to explore the plasticity of body representation. In this paper, we show that women can experience ownership over a whole virtual body that is considerably smaller or larger than their physical body. In order to gain a better understanding of the mechanisms underlying body ownership, we use an embodiment questionnaire, and introduce two new behavioral response measures: an affordance estimation task (indirect measure of body size) and a body size estimation task (direct measure of body size). Interestingly, after viewing the virtual body from first person perspective, both the affordance and the body size estimation tasks indicate a change in the perception of the size of the participant's experienced body. The change is biased by the size of the virtual body (overweight or underweight). Another novel aspect of our study is that we distinguish between the physical, experienced and virtual bodies, by asking participants to provide affordance and body size estimations for each of the three bodies separately. This methodological point is important for virtual reality experiments investigating body ownership of a virtual body, because it offers a better understanding of which cues (e.g. visual, proprioceptive, memory, or a combination thereof) influence body perception, and whether the impact of these cues can vary between different setups.

Owning an Overweight or Underweight Body: Distinguishing the Physical, Experienced and Virtual Body

PubMed Central

Piryankova, Ivelina V.; Wong, Hong Yu; Linkenauger, Sally A.; Stinson, Catherine; Longo, Matthew R.; Bülthoff, Heinrich H.; Mohler, Betty J.

2014-01-01

Our bodies are the most intimately familiar objects we encounter in our perceptual environment. Virtual reality provides a unique method to allow us to experience having a very different body from our own, thereby providing a valuable method to explore the plasticity of body representation. In this paper, we show that women can experience ownership over a whole virtual body that is considerably smaller or larger than their physical body. In order to gain a better understanding of the mechanisms underlying body ownership, we use an embodiment questionnaire, and introduce two new behavioral response measures: an affordance estimation task (indirect measure of body size) and a body size estimation task (direct measure of body size). Interestingly, after viewing the virtual body from first person perspective, both the affordance and the body size estimation tasks indicate a change in the perception of the size of the participant's experienced body. The change is biased by the size of the virtual body (overweight or underweight). Another novel aspect of our study is that we distinguish between the physical, experienced and virtual bodies, by asking participants to provide affordance and body size estimations for each of the three bodies separately. This methodological point is important for virtual reality experiments investigating body ownership of a virtual body, because it offers a better understanding of which cues (e.g. visual, proprioceptive, memory, or a combination thereof) influence body perception, and whether the impact of these cues can vary between different setups. PMID:25083784

Reconfigurable paramagnetic microswimmers: Brownian motion affects non-reciprocal actuation.

PubMed

Du, Di; Hilou, Elaa; Biswal, Sibani Lisa

2018-05-09

Swimming at low Reynolds number is typically dominated by a large viscous drag, therefore microscale swimmers require non-reciprocal body deformation to generate locomotion. Purcell described a simple mechanical swimmer at the microscale consisting of three rigid components connected together with two hinges. Here we present a simple microswimmer consisting of two rigid paramagnetic particles with different sizes. When placed in an eccentric magnetic field, this simple microswimmer exhibits non-reciprocal body motion and its swimming locomotion can be directed in a controllable manner. Additional components can be added to create a multibody microswimmer, whereby the particles act cooperatively and translate in a given direction. For some multibody swimmers, the stochastic thermal forces fragment the arm, which therefore modifies the swimming strokes and changes the locomotive speed. This work offers insight into directing the motion of active systems with novel time-varying magnetic fields. It also reveals that Brownian motion not only affects the locomotion of reciprocal swimmers that are subject to the Scallop theorem, but also affects that of non-reciprocal swimmers.

Accuracy of self- and parental perception of overweight among Latino preadolescents.

PubMed

Intagliata, Valentina; Ip, Edward H; Gesell, Sabina B; Barkin, Shari L

2008-01-01

This investigation examines self-perception and parental perception of child body size and factors associated with accurate parental perception of child body size. Latino at-risk for overweight (AROW) and/or overweight preadolescent children (ages 8-11 years) along with their parents were recruited (N=123 dyads). Children's body mass index (BMI) was measured but not discussed before participants were shown pictures of body sizes and asked to select the image that represented the child's body. The correlation between the child's body size selection and the child's actual BMI was 0.117 (p=0.20) whereas the correlation between the parent's assessment of the child's body size and the child's actual BMI was 0.470 (p<0.001). Logistic regression revealed that only parental education level (> or =college) was associated with a more accurate parental perception of their child's body size (OR: 0.11/95% CI: 0.01, 0.89) while child's sex, parental BMI, and parental health status were not associated with a perception that corresponded to the child's BMI. The sample was drawn from a single community clinic in Forsyth County which serves a large population of newer Latino immigrants in the county. The results indicate that (1) Latino AROW/overweight preadolescent children do not have an accurate perception of their own body size; (2) Latino parents have a more accurate perception of their child's body size with a moderately sized correlation suggesting that their perception of their child's body size is frequently inaccurate; and (3) Latino parents with higher education perceive their child's body size more accurately than less educated parents.

Differences in the effectiveness of frontal air bags by body size among adults involved in motor vehicle crashes.

PubMed

Newgard, Craig D; McConnell, K John

2008-10-01

There is concern that small stature occupants (particularly women) involved in motor vehicle crashes (MVCs) may be at risk of injury or death from frontal air bags, though evidence to substantiate this concern is lacking. We sought to assess how occupant body size (measured through height and weight) affects air bag effectiveness in mitigating the risk of serious injury, after adjusting for important crash factors. This was a retrospective cohort study using a national population-based cohort of adult front-seat occupants involved in MVCs as included in the National Automotive Sampling System Crashworthiness Data System database (NASS CDS) from 1995 to 2006. Drivers and front-seat passengers 15 years and older involved in MVCs involving passenger vehicles and light trucks were included in the analysis. The primary outcome was serious injury, defined as an Abbreviated Injury Scale (AIS) score >or=3 in any body region. Multivariable logistic regression models were used to test interaction terms (effect modification) between air bags, body size, and injury. The predicted probability of injury across body sizes was plotted to further illustrate potential differences. Sixty-nine thousand three hundred eighty-seven adult front-seat occupants during the 12-year period were included in the analysis, of which 9333 (2.3%) were seriously injured. There was no evidence that height or weight modified air bag effectiveness among all crashes (p > .40). In primary frontal collisions, there was some evidence for effect modification by weight (p = .04) but not by height (p = .59). When assessed using air bag deployment, height was a strong effect modifier (p = .0078), but not weight (p = .43). Predicted probability figures confirmed that occupant height modifies the effect of air bag deployment, but there was no similar visual evidence for body weight. In this sample, we found no consistent evidence that body size modifies the overall effectiveness of frontal air bags. However, among crashes involving air bag deployment, the effect of deployment on injury differs by occupant height, with a relative increase in the odds of serious injury among smaller occupants. In such crashes, the probability of injury with (versus without) deployment began to increase with occupant heights less than 155 cm (5'), reaching a level of statistical difference below 138 cm (4' 6'').

Common determinants of body size and eye size in chickens from an advanced intercross line.

PubMed

Prashar, Ankush; Hocking, Paul M; Erichsen, Jonathan T; Fan, Qiao; Saw, Seang Mei; Guggenheim, Jeremy A

2009-06-15

Myopia development is characterised by an increased axial eye length. Therefore, identifying factors that influence eye size may provide new insights into the aetiology of myopia. In humans, axial length is positively correlated to height and weight, and in mice, eye weight is positively correlated with body weight. The purpose of this study was to examine the relationship between eye size and body size in chickens from a genetic cross in which alleles with major effects on eye and body size were segregating. Chickens from a cross between a layer line (small body size and eye size) and a broiler line (large body and eye size) were interbred for 10 generations so that alleles for eye and body size would have the chance to segregate independently. At 3 weeks of age, 510 chicks were assessed using in vivo high resolution A-scan ultrasonography and keratometry. Equatorial eye diameter and eye weight were measured after enucleation. The variations in eye size parameters that could be explained by body weight (BW), body length (BL), head width (HW) and sex were examined using multiple linear regression. It was found that BW, BL and HW and sex together predicted 51-56% of the variation in eye weight, axial length, corneal radius, and equatorial eye diameter. By contrast, the same variables predicted only 22% of the variation in lens thickness. After adjusting for sex, the three body size parameters predicted 45-49% of the variation in eye weight, axial length, corneal radius, and eye diameter, but only 0.4% of the variation in lens thickness. In conclusion, about half of the variation in eye size in the chickens of this broiler-layer advanced intercross line is likely to be determined by pleiotropic genes that also influence body size. Thus, mapping the quantitative trait loci (QTL) that determine body size may be useful in understanding the genetic determination of eye size (a logical inference of this result is that the 20 or more genetic variants that have recently been shown to influence human height may also be found to influence axial eye length). Furthermore, adjusting for body size will be essential in mapping pure eye size QTL in this chicken population, and may also have value in mapping eye size QTL in humans.

Metabolic rate and body size are linked with perception of temporal information☆

PubMed Central

Healy, Kevin; McNally, Luke; Ruxton, Graeme D.; Cooper, Natalie; Jackson, Andrew L.

2013-01-01

Body size and metabolic rate both fundamentally constrain how species interact with their environment, and hence ultimately affect their niche. While many mechanisms leading to these constraints have been explored, their effects on the resolution at which temporal information is perceived have been largely overlooked. The visual system acts as a gateway to the dynamic environment and the relative resolution at which organisms are able to acquire and process visual information is likely to restrict their ability to interact with events around them. As both smaller size and higher metabolic rates should facilitate rapid behavioural responses, we hypothesized that these traits would favour perception of temporal change over finer timescales. Using critical flicker fusion frequency, the lowest frequency of flashing at which a flickering light source is perceived as constant, as a measure of the maximum rate of temporal information processing in the visual system, we carried out a phylogenetic comparative analysis of a wide range of vertebrates that supported this hypothesis. Our results have implications for the evolution of signalling systems and predator–prey interactions, and, combined with the strong influence that both body mass and metabolism have on a species' ecological niche, suggest that time perception may constitute an important and overlooked dimension of niche differentiation. PMID:24109147

Time budgets of Snow Geese Chen caerulescens and Ross's Geese Chen rossii in mixed flocks: Implications of body size, ambient temperature and family associations

USGS Publications Warehouse

Jonsson, J.E.; Afton, A.D.

2009-01-01

Body size affects foraging and forage intake rates directly via energetic processes and indirectly through interactions with social status and social behaviour. Ambient temperature has a relatively greater effect on the energetics of smaller species, which also generally are more vulnerable to predator attacks than are larger species. We examined variability in an index of intake rates and an index of alertness in Lesser Snow Geese Chen caerulescens caerulescens and Ross's Geese Chen rossii wintering in southwest Louisiana. Specifically we examined variation in these response variables that could be attributed to species, age, family size and ambient temperature. We hypothesized that the smaller Ross's Geese would spend relatively more time feeding, exhibit relatively higher peck rates, spend more time alert or raise their heads up from feeding more frequently, and would respond to declining temperatures by increasing their proportion of time spent feeding. As predicted, we found that Ross's Geese spent more time feeding than did Snow Geese and had slightly higher peck rates than Snow Geese in one of two winters. Ross's Geese spent more time alert than did Snow Geese in one winter, but alert rates differed by family size, independent of species, in contrast to our prediction. In one winter, time spent foraging and walking was inversely related to average daily temperature, but both varied independently of species. Effects of age and family size on time budgets were generally independent of species and in accordance with previous studies. We conclude that body size is a key variable influencing time spent feeding in Ross's Geese, which may require a high time spent feeding at the expense of other activities. ?? 2008 The Authors.

A Caenorhabditis elegans Wild Type Defies the Temperature–Size Rule Owing to a Single Nucleotide Polymorphism in tra-3

PubMed Central

Kammenga, Jan E; Doroszuk, Agnieszka; Riksen, Joost A. G; Hazendonk, Esther; Spiridon, Laurentiu; Petrescu, Andrei-Jose; Tijsterman, Marcel; Plasterk, Ronald H. A; Bakker, Jaap

2007-01-01

Ectotherms rely for their body heat on surrounding temperatures. A key question in biology is why most ectotherms mature at a larger size at lower temperatures, a phenomenon known as the temperature–size rule. Since temperature affects virtually all processes in a living organism, current theories to explain this phenomenon are diverse and complex and assert often from opposing assumptions. Although widely studied, the molecular genetic control of the temperature–size rule is unknown. We found that the Caenorhabditis elegans wild-type N2 complied with the temperature–size rule, whereas wild-type CB4856 defied it. Using a candidate gene approach based on an N2 × CB4856 recombinant inbred panel in combination with mutant analysis, complementation, and transgenic studies, we show that a single nucleotide polymorphism in tra-3 leads to mutation F96L in the encoded calpain-like protease. This mutation attenuates the ability of CB4856 to grow larger at low temperature. Homology modelling predicts that F96L reduces TRA-3 activity by destabilizing the DII-A domain. The data show that size adaptation of ectotherms to temperature changes may be less complex than previously thought because a subtle wild-type polymorphism modulates the temperature responsiveness of body size. These findings provide a novel step toward the molecular understanding of the temperature–size rule, which has puzzled biologists for decades. PMID:17335351

Correlates of self worth and body size dissatisfaction among obese Latino youth

PubMed Central

Mirza, Nazrat M; Mackey, Eleanor Race; Armstrong, Bridget; Jaramillo, Ana; Palmer, Matilde M

2011-01-01

The current study examined self-worth and body size dissatisfaction, and their association with maternal acculturation among obese Latino youth enrolled in a community-based obesity intervention program. Upon entry to the program, a sample of 113 participants reported global self-worth comparable to general population norms, but lower athletic competence and perception of physical appearance. Interestingly, body size dissatisfaction was more prevalent among younger respondents. Youth body size dissatisfaction was associated with less acculturated mothers and higher maternal dissatisfaction with their child's body size. By contrast, although global self-worth was significantly related to body dissatisfaction, it was not influenced by mothers’ acculturation or dissatisfaction with their own or their child’s body size. Obesity intervention programs targeted to Latino youth need to address self-worth concerns among the youth as well as addressing maternal dissatisfaction with their children’s body size. PMID:21354881

Humans preserve non-human primate pattern of climatic adaptation

NASA Astrophysics Data System (ADS)

Buck, Laura T.; De Groote, Isabelle; Hamada, Yuzuru; Stock, Jay T.

2018-07-01

There is evidence for early Pleistocene Homo in northern Europe, a novel hominin habitat. Adaptations enabling this colonisation are intriguing given suggestions that Homo exhibits physiological and behavioural malleability associated with a 'colonising niche'. Differences in body size/shape between conspecifics from different climates are well-known in mammals, could relatively flexible size/shape have been important to Homo adapting to cold habitats? If so, at what point did this evolutionary stragegy arise? To address these questions a base-line for adaptation to climate must be established by comparison with outgroups. We compare skeletons of Japanese macaques from four latitudes and find inter-group differences in postcranial and cranial size and shape. Very small body mass and cranial size in the Southern-most (island) population are most likely affected by insularity as well as ecogeographic scaling. Limb lengths and body breadths show group differences that accord with the expectations of thermoregulation across the whole range of latitudes. Postcranial size appears to vary more than shape, yet there is also evidence that limb segments follow Allen's rule in the forelimb at least, suggesting differing climatic signals in different regions of the skeleton. In contrast to other intraspecific studies of catarrhine ecogeography, the results presented here demonstrate non-allometric latitudinal patterns in craniofacial shape in Japanese macaques, which align closely with what is seen in cold-adapted humans. These insights begin to provide a comparison for hominin adaptation to similar habitat diversity and the role of biological adaptation in shaping the evolution and dispersal of Homo species.

The effect of body size on the rate of decomposition in a temperate region of South Africa.

PubMed

Sutherland, A; Myburgh, J; Steyn, M; Becker, P J

2013-09-10

Forensic anthropologists rely on the state of decomposition of a body to estimate the post-mortem-interval (PMI) which provides information about the natural events and environmental forces that could have affected the remains after death. Various factors are known to influence the rate of decomposition, among them temperature, rainfall and exposure of the body. However, conflicting reports appear in the literature on the effect of body size on the rate of decay. The aim of this project was to compare decomposition rates of large pigs (Sus scrofa; 60-90 kg), with that of small pigs (<35 kg), to assess the influence of body size on decomposition rates. For the decomposition rates of small pigs, 15 piglets were assessed three times per week over a period of three months during spring and early summer. Data collection was conducted until complete skeletonization occurred. Stages of decomposition were scored according to separate categories for each anatomical region, and the point values for each region were added to determine the total body score (TBS), which represents the overall stage of decomposition for each pig. For the large pigs, data of 15 pigs were used. Scatter plots illustrating the relationships between TBS and PMI as well as TBS and accumulated degree days (ADD) were used to assess the pattern of decomposition and to compare decomposition rates between small and large pigs. Results indicated that rapid decomposition occurs during the early stages of decomposition for both samples. Large pigs showed a plateau phase in the course of advanced stages of decomposition, during which decomposition was minimal. A similar, but much shorter plateau was reached by small pigs of >20 kg at a PMI of 20-25 days, after which decomposition commenced swiftly. This was in contrast to the small pigs of <20 kg, which showed no plateau phase and their decomposition rates were swift throughout the duration of the study. Overall, small pigs decomposed 2.82 times faster than large pigs, indicating that body size does have an effect on the rate of decomposition. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Weibel-Palade bodies at a glance.

PubMed

McCormack, Jessica J; Lopes da Silva, Mafalda; Ferraro, Francesco; Patella, Francesca; Cutler, Daniel F

2017-11-01

The vascular environment can rapidly alter, and the speed with which responses to both physiological and pathological changes are required necessitates the existence of a highly responsive system. The endothelium can quickly deliver bioactive molecules by regulated exocytosis of its secretory granules, the Weibel-Palade bodies (WPBs). WPBs include proteins that initiate both haemostasis and inflammation, as well those that modulate blood pressure and angiogenesis. WPB formation is driven by von Willebrand factor, their most abundant protein, which controls both shape and size of WPBs. WPB are generated in a range of sizes, with the largest granules over ten times the size of the smallest. In this Cell Science at a Glance and the accompanying poster, we discuss the emerging mechanisms by which WPB size is controlled and how this affects the ability of this organelle to modulate haemostasis. We will also outline the different modes of exocytosis and their polarity that are currently being explored, and illustrate that these large secretory organelles provide a model for how elements of secretory granule biogenesis and exocytosis cooperate to support a complex and diverse set of functions. © 2017. Published by The Company of Biologists Ltd.

Mesh size selectivity of the gillnet in East China Sea

NASA Astrophysics Data System (ADS)

Li, L. Z.; Tang, J. H.; Xiong, Y.; Huang, H. L.; Wu, L.; Shi, J. J.; Gao, Y. S.; Wu, F. Q.

2017-07-01

A production test using several gillnets with various mesh sizes was carried out to discover the selectivity of gillnets in the East China Sea. The result showed that the composition of the catch species was synthetically affected by panel height and mesh size. The bycatch species of the 10-m nets were more than those of the 6-m nets. For target species, the effect of panel height on juvenile fish was ambiguous, but the number of juvenile fish declined quickly with the increase in mesh size. According to model deviance (D) and Akaike’s information criterion, the bi-normal model provided the best fit for small yellow croaker (Larimichthy polyactis), and the relative retention was 0.2 and 1, respectively. For Chelidonichthys spinosus, the log-normal was the best model; the right tilt of the selectivity curve was obvious and well coincided with the original data. The contact population of small yellow croaker showed a bi-normal distribution, and body lengths ranged from 95 to 215 mm. The contact population of C. spinosus showed a normal distribution, and the body lengths ranged from 95 to 205 mm. These results can provide references for coastal fishery management.

Experimental evolution in Drosophila melanogaster: interaction of temperature and food quality selection regimes.

PubMed

Bochdanovits, Zoltán; de Jong, Gerdien

2003-08-01

In Drosophila, both the phenotypic and evolutionary effect of temperature on adult size involves alterations to larval resource processing and affects other life-history traits, that is, development time but most notably, larval survival. Therefore, thermal evolution of adult body size might not be independent of simultaneous adaptation of larval traits to resource availability. Using experimental evolution lines adapted to high and low temperatures at different levels of food, we show that selection pressures interact in shaping larval resource processing. Evolution on poor food invariably leads to lower resource acquisition suggesting a cost to feeding behavior. However, following low temperature selection, lower resource acquisition led to a higher adult body size, probably by more efficient allocation to growth. In contrast, following high temperature selection, low resource acquisition benefited larval survival, possibly by reducing feeding-associated costs. We show that evolved differences to larval resource processing provide a possible proximate mechanism to variation in a suite of correlated life-history traits during adaptation to different climates. The implication for natural populations is that in nature, thermal evolution drives populations to opposite ends of an adult size versus larval survival trade-off by altering resource processing, if resource availability is limited.

Body size perceptions among Pakistani women in Norway participating in a controlled trial to prevent deterioration of glucose tolerance.

PubMed

Hussain, Aysha; Bjørge, Benedikte; Hjellset, Victoria T; Holmboe-Ottesen, Gerd; Wandel, Margareta

2010-06-01

South Asians are prone to diabetes type 2 and cardiovascular diseases, which can be prevented by a diet leading to weight reduction. Body size perceptions may influence compliance to dietary advice. The objective was to study body size perceptions among Pakistani immigrant women in Norway, enrolled in a controlled trial to prevent deterioration of glucose tolerance by focussing on diet and physical activity. Participants (n=198) were 25-62 years of age, 79.8% had BMI > 25 and mean BMI was 29.6. Data were collected by questionnaire interviews with Punjabi/Urdu speaking interviewers, and body weight and height were measured. This article is based on baseline data. Stunkard's Figure Rating Scale was used. The scale consists of nine figures, representing women with different body shapes, from very thin (1-2) to very obese (6-9). The women were asked which body size they thought would connote health and wealth. A significantly smaller body size was related to health (mean 2.9) than to wealth (mean 3.3), p<0.01, and both were smaller than their self-rated own body size (mean 5.7), p<0.01. The women perceived that Pakistanis in Norway prefer women to have a smaller body size (mean 3.4) than people in Pakistan (mean 4.5), but larger than Norwegians (mean 2.5). A discrepancy score was calculated between self-rated own body size and perceived body size preference among Pakistanis in Norway. BMI was positively associated, and level of education negatively associated, with the discrepancy score. The women related body size numbers to BMI similarly to what has been described for US women. In conclusion, body size preferences among Pakistani women in this study were within the range of normal weight. However, there was a large discrepancy between own self-rated body size and the perceived ideal for Pakistanis in Norway.

Relation of Body Size on Ecological Modes

NASA Astrophysics Data System (ADS)

Ivanov, A.; Ngo, A.; Heim, N.; Payne, J.

2016-12-01

Body size in the manner of total biovolume is a useful metric for determining the way an organism interacts with its environment. Body sizes of an organism determines behavior and its life mode, the way an organism lives and survives defined by motility, depth of habitat, and feeding mode. To build on that, we hypothesize that the body size of organisms determines the amount of unique life modes an organism is capable of utilizing. the We categorized the ecological life modes of marine organisms in the phyla Arthropoda, Mollusca, Chordata, and Brachiopoda. After organizing body sizes into bins of 10,000 mm3 per x-value through R, a trend displaying a decrease in the amount of unique life modes per body size bin is visible with increasing size. Chordates however do not display as consistent of a trend as do the rest of the phyla. We hypothesize that this could be because most chordates have a backbone allowing more variation in life modes and behaviors which in turn are capable sustain larger body sizes. A boxplot regarding the range of unique life modes for all body sizes for all phyla also shows that a majority of life mode ranges range from the median size organisms from data collected to the smallest. Which means that with all of the unique life modes that were taken into consideration, the possible body sizes they ranged into were mostly into smaller organisms as there was a majority in life modes that did not range into the realm of larger body size organisms that were greater than the median sizes of the organisms.

Effect of meal size and body size on specific dynamic action and gastric processing in decapod crustaceans.

PubMed

McGaw, Iain J; Curtis, Daniel L

2013-11-01

Meal size and animal size are important factors affecting the characteristics of the specific dynamic action (SDA) response across a variety of taxa. The effects of these two variables on the SDA of decapod crustaceans are based on just a couple of articles, and are not wholly consistent with the responses reported for other aquatic ectotherms. Therefore, the effects of meal size and animal size on the characteristics of SDA response were investigated in a variety of decapod crustaceans from different families. A 6 fold increase in meal size (0.5%-3% body mass) resulted a pronounced increase in the duration of increased oxygen consumption, resulting in an increase in the SDA of Callinectes sapidus, Cancer gracilis, Hemigrapsus nudus, Homarus americanus, Pugettia producta and Procambarus clarkii. Unlike many other aquatic ectotherms a substantial increase between meal sizes was required, with meal size close to their upper feeding limit (3% body mass), before changes were evident. In many organisms increases in both duration and scope contribute to the overall SDA, here changes in scope as a function of meal size were weak, suggesting that a similar amount of energy is required to upregulate gastric processes, regardless of meal size. The SDA characteristics were less likely to be influenced by the size of the animal, and there was no difference in the SDA (kJ) as a function of size in H. americanus or Cancer irroratus when analysed as mass specific values. In several fish species characteristics of the SDA response are more closely related to the transit times of food, rather than the size of a meal. To determine if a similar trend occurred in crustaceans, the transit rates of different sized meals were followed through the digestive system using a fluoroscope. Although there was a trend towards larger meals taking longer to pass through the gut, this was only statistically significant for P. clarkii. There were some changes in transit times as a function of animal size. The foregut clearance times for Cancer magister increased with increasing body size, while smaller Carcinus maenas cleared the hindgut region at a faster rate than larger individuals. Unlike fish there was no clear relationship between transit rates and any of the SDA characteristics. While the fluoroscopy method is useful for assessing foregut activity and food passage, it is limited when inferring connections between nutrient assimilation and post-absorptive processes in crustaceans. Therefore, at least with respect to meal size, transit rates do not make a good proxy for determining the SDA characteristics in crustaceans. © 2013.

Environment-dependence of behavioural consistency in adult male European green lizards (Lacerta viridis).

PubMed

Horváth, Gergely; Mészáros, Boglárka; Urszán, Tamás János; Bajer, Katalin; Molnár, Orsolya; Garamszegi, László Zsolt; Herczeg, Gábor

2017-01-01

Understanding the background mechanisms affecting the emergence and maintenance of consistent between-individual variation within population in single (animal personality) or across multiple (behavioural syndrome) behaviours has key importance. State-dependence theory suggests that behaviour is 'anchored' to individual state (e.g. body condition, gender, age) and behavioural consistency emerges through behavioural-state feedbacks. A number of relevant state variables are labile (e.g. body condition, physiological performance) and expected to be affected by short-term environmental change. Yet, whether short-term environmental shifts affect behavioural consistency during adulthood remains questionable. Here, by employing a full-factorial laboratory experiment, we explored if quantity of food (low vs. high) and time available for thermoregulation (3h vs. 10h per day) had an effect on activity and risk-taking of reproductive adult male European green lizards (Lacerta viridis). We focussed on different components of behavioural variation: (i) strength of behavioural consistency (repeatability for animal personality; between-individual correlation for behavioural syndrome), (ii) behavioural type (individual mean behaviour) and (iii) behavioural predictability (within-individual behavioural variation). Activity was repeatable in all treatments. Risk-taking was repeatable only in the low basking treatments. We found significant between-individual correlation only in the low food × long basking time group. The treatments did not affect behavioural type, but affected behavioural predictability. Activity predictability was higher in the short basking treatment, where it also decreased with size (≈ age). Risk-taking predictability in the short basking treatment increased with size under food limitation, but decreased when food supply was high. We conclude that short-term environmental change can alter various components of behavioural consistency. The effect could be detected in the presence/absence patterns of animal personality and behavioural syndrome and the level of individual behavioural predictability, but not in behavioural type.

No Effect of Body Size on the Frequency of Calling and Courtship Song in the Two-Spotted Cricket, Gryllus bimaculatus.

PubMed

Miyashita, Atsushi; Kizaki, Hayato; Sekimizu, Kazuhisa; Kaito, Chikara

2016-01-01

The relationship between body size and vocalization parameters has been studied in many animal species. In insect species, however, the effect of body size on song frequency has remained unclear. Here we analyzed the effect of body size on the frequency spectra of mating songs produced by the two-spotted cricket, Gryllus bimaculatus. We recorded the calling songs and courtship songs of male crickets of different body sizes. The calling songs contained a frequency component that peaked at 5.7 kHz. On the other hand, courtship songs contained two frequency components that peaked at 5.8 and 14.7 kHz. The dominant frequency of each component in both the calling and courtship songs was constant regardless of body size. The size of the harp and mirror regions in the cricket forewings, which are the acoustic sources of the songs, correlated positively with body size. These findings suggest that the frequency contents of both the calling and courtship songs of the cricket are unaffected by whole body, harp, or mirror size.

Effects of exposure to bodies of different sizes on perception of and satisfaction with own body size: two randomized studies.

PubMed

Bould, Helen; Carnegie, Rebecca; Allward, Heather; Bacon, Emily; Lambe, Emily; Sapseid, Megan; Button, Katherine S; Lewis, Glyn; Skinner, Andy; Broome, Matthew R; Park, Rebecca; Harmer, Catherine J; Penton-Voak, Ian S; Munafò, Marcus R

2018-05-01

Body dissatisfaction is prevalent among women and associated with subsequent obesity and eating disorders. Exposure to images of bodies of different sizes has been suggested to change the perception of 'normal' body size in others. We tested whether exposure to different-sized (otherwise identical) bodies changes perception of own and others' body size, satisfaction with body size and amount of chocolate consumed. In Study 1, 90 18-25-year-old women with normal BMI were randomized into one of three groups to complete a 15 min two-back task using photographs of women either of 'normal weight' (Body Mass Index (BMI) 22-23 kg m -2 ), or altered to appear either under- or over-weight. Study 2 was identical except the 96 participants had high baseline body dissatisfaction and were followed up after 24 h. We also conducted a mega-analysis combining both studies. Participants rated size of others' bodies, own size, and satisfaction with size pre- and post-task. Post-task ratings were compared between groups, adjusting for pre-task ratings. Participants exposed to over- or normal-weight images subsequently perceived others' bodies as smaller, in comparison to those shown underweight bodies ( p  < 0.001). They also perceived their own bodies as smaller (Study 1, p  = 0.073; Study 2, p  = 0.018; mega-analysis, p  = 0.001), and felt more satisfied with their size (Study 1, p  = 0.046; Study 2, p  = 0.004; mega-analysis, p  = 0.006). There were no differences in chocolate consumption. This study suggests that a move towards using images of women with a BMI in the healthy range in the media may help to reduce body dissatisfaction, and the associated risk of eating disorders.

Effects of exposure to bodies of different sizes on perception of and satisfaction with own body size: two randomized studies

PubMed Central

Carnegie, Rebecca; Allward, Heather; Bacon, Emily; Lambe, Emily; Sapseid, Megan; Button, Katherine S.; Lewis, Glyn; Skinner, Andy; Broome, Matthew R.; Park, Rebecca; Penton-Voak, Ian S.

2018-01-01

Body dissatisfaction is prevalent among women and associated with subsequent obesity and eating disorders. Exposure to images of bodies of different sizes has been suggested to change the perception of ‘normal’ body size in others. We tested whether exposure to different-sized (otherwise identical) bodies changes perception of own and others' body size, satisfaction with body size and amount of chocolate consumed. In Study 1, 90 18–25-year-old women with normal BMI were randomized into one of three groups to complete a 15 min two-back task using photographs of women either of ‘normal weight’ (Body Mass Index (BMI) 22–23 kg m−2), or altered to appear either under- or over-weight. Study 2 was identical except the 96 participants had high baseline body dissatisfaction and were followed up after 24 h. We also conducted a mega-analysis combining both studies. Participants rated size of others' bodies, own size, and satisfaction with size pre- and post-task. Post-task ratings were compared between groups, adjusting for pre-task ratings. Participants exposed to over- or normal-weight images subsequently perceived others' bodies as smaller, in comparison to those shown underweight bodies (p < 0.001). They also perceived their own bodies as smaller (Study 1, p = 0.073; Study 2, p = 0.018; mega-analysis, p = 0.001), and felt more satisfied with their size (Study 1, p = 0.046; Study 2, p = 0.004; mega-analysis, p = 0.006). There were no differences in chocolate consumption. This study suggests that a move towards using images of women with a BMI in the healthy range in the media may help to reduce body dissatisfaction, and the associated risk of eating disorders. PMID:29892352

Testing the norm to fat talk for women of varying size: what's weight got to do with it?

PubMed

Barwick, Amy; Bazzini, Doris; Martz, Denise; Rocheleau, Courtney; Curtin, Lisa

2012-01-01

"Fat talk" is the conversational phenomenon whereby people berate their bodies in social circles. This study assessed whether norms of fat talk differ for overweight versus average-weight women. Sixty-three women read a script depicting a fat talk situation during which an overweight or average-weight target woman engaged in positive or negative body talk. Regardless of the target's weight, participants perceived it to be more typical and less surprising if she engaged in negative body talk (fat talk) rather than positive body talk. Furthermore, fat talk from either weight group did not affect the likeability of the target, but women, overweight or of average weight, who engaged in positive talk were perceived to have more socially desirable personality characteristics. Copyright © 2011 Elsevier Ltd. All rights reserved.

Motion-oriented 3D analysis of body measurements

NASA Astrophysics Data System (ADS)

Loercher, C.; Morlock, S.; Schenk, A.

2017-10-01

The aim of this project is to develop an ergonomically based and motion-oriented size system. New concepts are required in order to be able to deal competently with complex requirements of function-oriented workwear and personal protective equipment (PPE). Body dimensions change through movement, which are basis for motion optimized clothing development. This affects fit and ergonomic comfort. The situation has to be fundamentally researched in order to derive well-founded anthropometric body data, taking into account kinematic requirements of humans and to define functional dimensions for clothing industry. Research focus shall be on ergonomic design of workwear and PPE. There are huge differences in body forms, proportions and muscle manifestations between genders. An improved basic knowledge can be provided as a result, supporting development as well as sales of motion-oriented clothing with perfect fit for garment manufacturers.

Study of the flying ability of Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) adults using a computer-monitored flight mill.

PubMed

Ávalos, J A; Martí-Campoy, A; Soto, A

2014-08-01

The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae), native to tropical Asian regions, has become a serious threat to palm trees all over the world. Knowledge of its flight potential is vital to improving the preventive and curative measures currently used to manage this pest. As R. ferrugineus is a quarantine pest, it is difficult to study its flight potential in the field. A computer-monitored flight mill was adapted to analyse the flying ability of R. ferrugineus through the study of different flight parameters (number of flights, total distance flown, longest single flight, flight duration, and average and maximum speed) and the influence of the weevil's sex, age, and body size on these flight parameters. Despite significant differences in the adult body size (body weight and length) of males and females, the sex of R. ferrugineus adults did not have an influence on their flight potential. Neither adult body size nor age was found to affect the weevil's flying abilities, although there was a significantly higher percentage of individuals flying that were 8-23 days old than 1-7 days old. Compared to the longest single flight, 54% of the insects were classified as short-distance flyers (covering <100 m) and 36 and 10% were classified as medium- (100-5000 m) and long-distance (>5000 m), respectively. The results are compared with similar studies on different insect species under laboratory and field conditions.

Survival suit volume reduction associated with immersion: implications for buoyancy estimation in offshore workers of different size.

PubMed

Stewart, Arthur; Ledingham, Robert; Furnace, Graham; Williams, Hector; Coleshaw, Susan

2017-06-01

It is currently unknown how body size affects buoyancy in submerged helicopter escape. Eight healthy males aged 39.6 ± 12.6 year (mean ± SD) with BMI 22.0-40.0 kg m -2 wearing a standard survival ('dry') suit undertook a normal venting manoeuvre and underwent 3D scanning to assess body volume (wearing the suit) before and after immersion in a swimming pool. Immersion-induced volume loss averaged 14.4 ± 5.4 l, decreased with increasing dry density (mass volume -1 ) and theoretical buoyant force in 588 UK offshore workers was found to be 264 ± 46 and 232 ± 60 N using linear and power functions, respectively. Both approaches revealed heavier workers to have greater buoyant force. While a larger sample may yield a more accurate buoyancy prediction, this study shows heavier workers are likely to have greater buoyancy. Without free-swimming capability to overcome such buoyancy, some individuals may possibly exceed the safe limit to enable escape from a submerged helicopter. Practitioner Summary: Air expulsion reduced total body volume of survival-suited volunteers following immersion by an amount inversely proportional to body size. When applied to 588 offshore workers, the predicted air loss suggested buoyant force to be greatest in the heaviest individuals, which may impede their ability to exit a submerged helicopter.

Do lizards and snakes really differ in their ability to take large prey? A study of relative prey mass and feeding tactics in lizards.

PubMed

Shine, Richard; Thomas, Jai

2005-07-01

Adaptations of snakes to overpower and ingest relatively large prey have attracted considerable research, whereas lizards generally are regarded as unable to subdue or ingest such large prey items. Our data challenge this assumption. On morphological grounds, most lizards lack the highly kinetic skulls that facilitate prey ingestion in macrostomate snakes, but (1) are capable of reducing large items into ingestible-sized pieces, and (2) have much larger heads relative to body length than do snakes. Thus, maximum ingestible prey size might be as high in some lizards as in snakes. Also, the willingness of lizards to tackle very large prey items may have been underestimated. Captive hatchling scincid lizards (Bassiana duperreyi) offered crickets of a range of relative prey masses (RPMs) attacked (and sometimes consumed parts of) crickets as large as or larger than their own body mass. RPM affected foraging responses: larger crickets were less likely to be attacked (especially on the abdomen), more likely to be avoided, and less likely to provide significant nutritional benefit to the predator. Nonetheless, lizards successfully attacked and consumed most crickets < or =35% of the predator's own body mass, representing RPM as high as for most prey taken by snakes. Thus, although lizards lack the impressive cranial kinesis or prey-subduction adaptations of snakes, at least some lizards are capable of overpowering and ingesting prey items as large as those consumed by snakes of similar body sizes.

The evolution of body size and shape in the human career

PubMed Central

Grabowski, Mark; Hatala, Kevin G.; Richmond, Brian G.

2016-01-01

Body size is a fundamental biological property of organisms, and documenting body size variation in hominin evolution is an important goal of palaeoanthropology. Estimating body mass appears deceptively simple but is laden with theoretical and pragmatic assumptions about best predictors and the most appropriate reference samples. Modern human training samples with known masses are arguably the ‘best’ for estimating size in early bipedal hominins such as the australopiths and all members of the genus Homo, but it is not clear if they are the most appropriate priors for reconstructing the size of the earliest putative hominins such as Orrorin and Ardipithecus. The trajectory of body size evolution in the early part of the human career is reviewed here and found to be complex and nonlinear. Australopith body size varies enormously across both space and time. The pre-erectus early Homo fossil record from Africa is poor and dominated by relatively small-bodied individuals, implying that the emergence of the genus Homo is probably not linked to an increase in body size or unprecedented increases in size variation. Body size differences alone cannot explain the observed variation in hominin body shape, especially when examined in the context of small fossil hominins and pygmy modern humans. This article is part of the themed issue ‘Major transitions in human evolution’. PMID:27298459

The evolution of body size and shape in the human career.

PubMed

Jungers, William L; Grabowski, Mark; Hatala, Kevin G; Richmond, Brian G

2016-07-05

Body size is a fundamental biological property of organisms, and documenting body size variation in hominin evolution is an important goal of palaeoanthropology. Estimating body mass appears deceptively simple but is laden with theoretical and pragmatic assumptions about best predictors and the most appropriate reference samples. Modern human training samples with known masses are arguably the 'best' for estimating size in early bipedal hominins such as the australopiths and all members of the genus Homo, but it is not clear if they are the most appropriate priors for reconstructing the size of the earliest putative hominins such as Orrorin and Ardipithecus The trajectory of body size evolution in the early part of the human career is reviewed here and found to be complex and nonlinear. Australopith body size varies enormously across both space and time. The pre-erectus early Homo fossil record from Africa is poor and dominated by relatively small-bodied individuals, implying that the emergence of the genus Homo is probably not linked to an increase in body size or unprecedented increases in size variation. Body size differences alone cannot explain the observed variation in hominin body shape, especially when examined in the context of small fossil hominins and pygmy modern humans.This article is part of the themed issue 'Major transitions in human evolution'. © 2016 The Author(s).

Environmental and scale-dependent evolutionary trends in the body size of crustaceans

PubMed Central

Klompmaker, Adiël A.; Schweitzer, Carrie E.; Feldmann, Rodney M.; Kowalewski, Michał

2015-01-01

The ecological and physiological significance of body size is well recognized. However, key macroevolutionary questions regarding the dependency of body size trends on the taxonomic scale of analysis and the role of environment in controlling long-term evolution of body size are largely unknown. Here, we evaluate these issues for decapod crustaceans, a group that diversified in the Mesozoic. A compilation of body size data for 792 brachyuran crab and lobster species reveals that their maximum, mean and median body size increased, but no increase in minimum size was observed. This increase is not expressed within lineages, but is rather a product of the appearance and/or diversification of new clades of larger, primarily burrowing to shelter-seeking decapods. This argues against directional selective pressures within lineages. Rather, the trend is a macroevolutionary consequence of species sorting: preferential origination of new decapod clades with intrinsically larger body sizes. Furthermore, body size evolution appears to have been habitat-controlled. In the Cretaceous, reef-associated crabs became markedly smaller than those in other habitats, a pattern that persists today. The long-term increase in body size of crabs and lobsters, coupled with their increased diversity and abundance, suggests that their ecological impact may have increased over evolutionary time. PMID:26156761

Assessment of body perception among Swedish adolescents and young adults.

PubMed

Bergström, E; Stenlund, H; Svedjehäll, B

2000-01-01

To assess body perception in adolescents and young adults without anorexia nervosa. Using a visual size estimation technique, perceived body size was estimated in four groups of Swedish adolescents and young adults without anorexia nervosa (86 males and 95 females). Perceived body size was estimated at nine different body sites comparing these estimations to real body size. The results show that 95% of males and 96% of females overestimated their body size (mean overestimation: males +22%, females +33%). The overestimations were greatest in females. The greatest overestimations were made of the waist (males +31%, females +46%), buttocks (males +22%, females +42%), and thighs (males +27%, females +41%). The results indicate that overestimation of body size may be a general phenomenon in adolescents and young adults in a country such as Sweden, implying a similar, but less pronounced distortion of body image as in individuals with anorexia nervosa.

Effects of Synthetic Diets Enriched in Specific Nutrients on Drosophila Development, Body Fat, and Lifespan.

PubMed

Reis, Tânia

2016-01-01

Gene-diet interactions play a crucial but poorly understood role in susceptibility to obesity. Accordingly, the development of genetically tractable model systems to study the influence of diets in obesity-prone genetic backgrounds is a focus of current research. Here I present a modified synthetic Drosophila diet optimized for timely larval development, a stage dedicated to energy storage. Specifically increasing the levels of individual macronutrients-carbohydrate, lipid, or protein-resulted in markedly different organismal effects. A high-carbohydrate diet adversely affected the timing of development, size, early lifespan and body fat. Strikingly, quadrupling the amount of dietary lipids had none of these effects. Diets rich in protein appeared to be the most beneficial, as larvae developed faster, with no change in size, into long-lived adults. I believe this synthetic diet will significantly facilitate the study of gene-diet interactions in organismal energy balance.

The ornament-condition relationship varies with parasite abundance at population level in a female bird

NASA Astrophysics Data System (ADS)

Vergara, Pablo; Martínez-Padilla, Jesús; Redpath, Stephen M.; Mougeot, Francois

2011-10-01

Environmental heterogeneity is expected to create variation in the ornament-condition relationship. This topic has been studied in males with less attention being given to females. Here, we explore inter-population variation in the relationship between the size of a male-like trait, supra-orbital combs, and body mass in female red grouse Lagopus lagopus scoticus. We used the abundance of the nematode Trichostrongylus tenuis, a parasite with strong negative effects on this species, as a proxy of environmental conditions. We studied six populations over 5 years and showed that the comb size-body mass relationship varied with mean parasite abundance, with stronger ornament-condition relationships in populations with higher parasite infection levels. Our study supports the idea that environmental conditions, and in particular parasite infection levels, may affect the reliability of female ornaments as condition indicators.

Reducing eating disorder risk factors: A pilot effectiveness trial of a train-the-trainer approach to dissemination and implementation.

PubMed

Greif, Rebecca; Becker, Carolyn Black; Hildebrandt, Tom

2015-12-01

Impediments limit dissemination and implementation of evidence-based interventions (EBIs), including lack of sufficient training. One strategy to increase implementation of EBIs is the train-the-trainer (TTT) model. The Body Project is a peer-led body image program that reduces eating disorder (ED) risk factors. This study examined the effectiveness of a TTT model at reducing risk factors in Body Project participants. Specifically, this study examined whether a master trainer could train a novice trainer to train undergraduate peer leaders to administer the Body Project such that individuals who received the Body Project (i.e., participants) would evidence comparable outcomes to previous trials. We hypothesized that participants would evidence reductions in ED risk factors, with effect sizes similar to previous trials. Utilizing a TTT model, a master trainer trained a novice trainer to train undergraduate peer leaders to administer the Body Project to undergraduate women. Undergraduate women aged 18 years or older who received the Body Project intervention participated in the trial and completed measures at baseline, post-treatment, and five-month follow-up. Primary outcomes included body dissatisfaction, thin ideal internalization, negative affect, and ED pathology. Participants demonstrated significant reductions in thin ideal internalization, ED pathology and body dissatisfaction at post-treatment and 5-month follow-up. At 5 months, using three different strategies for managing missing data, effect sizes were larger or comparable to earlier trials for 3 out of 4 variables. Results support a TTT model for Body Project implementation and the importance of utilizing sensitivity analyses for longitudinal datasets with missing data. © 2015 Wiley Periodicals, Inc.

Pre and Post-copulatory Selection Favor Similar Genital Phenotypes in the Male Broad Horned Beetle

PubMed Central

House, Clarissa M.; Sharma, M. D.; Okada, Kensuke; Hosken, David J.

2016-01-01

Sexual selection can operate before and after copulation and the same or different trait(s) can be targeted during these episodes of selection. The direction and form of sexual selection imposed on characters prior to mating has been relatively well described, but the same is not true after copulation. In general, when male–male competition and female choice favor the same traits then there is the expectation of reinforcing selection on male sexual traits that improve competitiveness before and after copulation. However, when male–male competition overrides pre-copulatory choice then the opposite could be true. With respect to studies of selection on genitalia there is good evidence that male genital morphology influences mating and fertilization success. However, whether genital morphology affects reproductive success in more than one context (i.e., mating versus fertilization success) is largely unknown. Here we use multivariate analysis to estimate linear and nonlinear selection on male body size and genital morphology in the flour beetle Gnatocerus cornutus, simulated in a non-competitive (i.e., monogamous) setting. This analysis estimates the form of selection on multiple traits and typically, linear (directional) selection is easiest to detect, while nonlinear selection is more complex and can be stabilizing, disruptive, or correlational. We find that mating generates stabilizing selection on male body size and genitalia, and fertilization causes a blend of directional and stabilizing selection. Differences in the form of selection across these bouts of selection result from a significant alteration of nonlinear selection on body size and a marginally significant difference in nonlinear selection on a component of genital shape. This suggests that both bouts of selection favor similar genital phenotypes, whereas the strong stabilizing selection imposed on male body size during mate acquisition is weak during fertilization. PMID:27371390

Elucidating mechanisms for insect body size: partial support for the oxygen-dependent induction of moulting hypothesis.

PubMed

Kivelä, Sami M; Viinamäki, Sonja; Keret, Netta; Gotthard, Karl; Hohtola, Esa; Välimäki, Panu

2018-01-25

Body size is a key life history trait, and knowledge of its mechanistic basis is crucial in life history biology. Such knowledge is accumulating for holometabolous insects, whose growth is characterised and body size affected by moulting. According to the oxygen-dependent induction of moulting (ODIM) hypothesis, moult is induced at a critical mass at which oxygen demand of growing tissues overrides the supply from the tracheal respiratory system, which principally grows only at moults. Support for the ODIM hypothesis is controversial, partly because of a lack of proper data to explicitly test the hypothesis. The ODIM hypothesis predicts that the critical mass is positively correlated with oxygen partial pressure ( P O 2 ) and negatively with temperature. To resolve the controversy that surrounds the ODIM hypothesis, we rigorously test these predictions by exposing penultimate-instar Orthosia gothica (Lepidoptera: Noctuidae) larvae to temperature and moderate P O 2  manipulations in a factorial experiment. The relative mass increment in the focal instar increased along with increasing P O 2 , as predicted, but there was only weak suggestive evidence of the temperature effect. Probably owing to a high measurement error in the trait, the effect of P O 2  on the critical mass was sex specific; high P O 2  had a positive effect only in females, whereas low P O 2  had a negative effect only in males. Critical mass was independent of temperature. Support for the ODIM hypothesis is partial because of only suggestive evidence of a temperature effect on moulting, but the role of oxygen in moult induction seems unambiguous. The ODIM mechanism thus seems worth considering in body size analyses. © 2018. Published by The Company of Biologists Ltd.

Automatic exposure control in CT: the effect of patient size, anatomical region and prescribed modulation strength on tube current and image quality.

PubMed

Papadakis, Antonios E; Perisinakis, Kostas; Damilakis, John

2014-10-01

To study the effect of patient size, body region and modulation strength on tube current and image quality on CT examinations that use automatic tube current modulation (ATCM). Ten physical anthropomorphic phantoms that simulate an individual as neonate, 1-, 5-, 10-year-old and adult at various body habitus were employed. CT acquisition of head, neck, thorax and abdomen/pelvis was performed with ATCM activated at weak, average and strong modulation strength. The mean modulated mAs (mAsmod) values were recorded. Image noise was measured at selected anatomical sites. The mAsmod recorded for neonate compared to 10-year-old increased by 30 %, 14 %, 6 % and 53 % for head, neck, thorax and abdomen/pelvis, respectively, (P < 0.05). The mAsmod was lower than the preselected mAs with the exception of the 10-year-old phantom. In paediatric and adult phantoms, the mAsmod ranged from 44 and 53 for weak to 117 and 93 for strong modulation strength, respectively. At the same exposure parameters image noise increased with body size (P < 0.05). The ATCM system studied here may affect dose differently for different patient habitus. Dose may decrease for overweight adults but increase for children older than 5 years old. Care should be taken when implementing ATCM protocols to ensure that image quality is maintained. • ATCM efficiency is related to the size of the patient's body. • ATCM should be activated without caution in overweight adult individuals. • ATCM may increase radiation dose in children older than 5 years old. • ATCM efficiency depends on the protocol selected for a specific anatomical region. • Modulation strength may be appropriately tuned to enhance ATCM efficiency.

Crowding of Drosophila larvae affects lifespan and other life-history traits via reduced availability of dietary yeast.

PubMed

Klepsatel, Peter; Procházka, Emanuel; Gáliková, Martina

2018-06-19

Conditions experienced during development have often long-lasting effects persisting into adulthood. In Drosophila, it is well-documented that larval crowding influences fitness-related traits such as body size, starvation resistance and lifespan. However, the underlying mechanism of this phenomenon is not well understood. Here, we show that the effects of increased larval density on life-history traits can be explained by decreased yeast availability in the diet during development. Yeast-poor larval diet alters various life-history traits and mimics the effects of larval crowding. In particular, reduced amount of yeast in larval diet prolongs developmental time, reduces body size, increases body fat content and starvation resistance, and prolongs Drosophila lifespan. Conversely, the effects of larval crowding can be rescued by increasing the concentration of the dietary yeast in the diet during development. Altogether, our results show that the well-known effects of larval crowding on life-history traits are mainly caused by the reduced availability of dietary yeasts due to increased larval competition. Copyright © 2018. Published by Elsevier Inc.

Effects of Anthropometrics and Body Size Changes on the Development of Personal Protective Equipment (PPE) Sizing Systems in the US Army

DTIC Science & Technology

2016-08-01

ANTHROPOMETRICS AND BODY SIZE CHANGES ON THE DEVELOPMENT OF PERSONAL PROTECTIVE EQUIPMENT (PPE) SIZING SYSTEMS IN THE US ARMY by Hyeg Joo Choi* Todd...EFFECTS OF ANTHROPOMETRICS AND BODY SIZE CHANGES ON THE DEVELOPMENT OF PERSONAL PROTECTIVE EQUIPMENT (PPE) SIZING SYSTEMS IN THE US ARMY 5a. CONTRACT...Universities (ORAU) Maryland, 4692 Millennium Drive, Suite 101, Belcamp, MD 21017 14. ABSTRACT Understanding body size and shape information of military

The influence of genetic and environmental factors in estimations of current body size, desired body size, and body dissatisfaction.

PubMed

Wade, T D; Bulik, C M; Heath, A C; Martin, N G; Eaves, L J

2001-08-01

The objective was to investigate the genetic epidemiology of figural stimuli. Standard figural stimuli were available from 5,325 complete twin pairs: 1,751 (32.9%) were monozygotic females, 1,068 (20.1%) were dizygotic females, 752 (14.1%) were monozygotic males, 495 (9.3%) were dizygotic males, and 1,259 (23.6%) were dizygotic male-female pairs. Univariate twin analyses were used to examine the influences on the individual variation in current body size and ideal body size. These data were analysed separately for men and women in each of five age groups. A factorial analysis of variance, with polychoric correlations between twin pairs as the dependent variable, and age, sex, zygosity, and the three interaction terms (age x sex, age x zygosity, sex x zygosity) as independent variables, was used to examine trends across the whole data set. Results showed genetic influences had the largest impact on the individual variation in current body size measures, whereas non-shared environmental influences were associated with the majority of individual variation in ideal body size. There was a significant main effect of zygosity (heritability) in predicting polychoric correlations for current body size and body dissatisfaction. There was a significant main effect of gender and zygosity in predicting ideal body size, with a gender x zygosity interaction. In common with BMI, heritability is important in influencing the estimation of current body size. Selection of desired body size for both men and women is more strongly influenced by environmental factors.

Body size preference and body weight perception among two migrant groups of non-Western origin.

PubMed

Nicolaou, Mary; Doak, Colleen; Dam, Rob van; Hosper, Karen; Seidell, Jaap; Stronks, Karien

2008-12-01

To evaluate body size preference, body weight perception and their relationship with actual weight in two migrant groups of non-Western origin, Turks and Moroccans; additionally, to study the association between body size preference and acculturation. Cross-sectional study. Amsterdam, The Netherlands. Males and females (18-30 years) were randomly selected from the population registry (n 451); participants, or at least one of their parents, were born in Turkey or Morocco. Body size preference was assessed using seven silhouette drawings and body weight perception was assessed by asking participants' opinion of own weight. Acculturation variables were generation status and two scale measures, cultural orientation and social contacts. Participants showed preference for a thin body size. The discrepancy between ideal and current size was significant in women but not men (P < 0.001). Perceived current body size was correlated with BMI (Spearman's correlation coefficient 0.60, P < 0.001 (men) and 0.73, P < 0.001 (women)). Among overweight participants (BMI = 25.0-29.9 kg/m2), 63-82 % of men and 35 % of women perceived themselves as 'average'. Paying attention to own body weight was associated with a discrepancy between ideal and current size among women and with perceiving oneself as 'overweight' among men. Body size preference was not significantly associated with the three acculturation variables. We did not observe a preference for large body sizes in these two non-Western migrant groups. Similar to Western populations, most women wished to be thinner than they were. This was not the case among men, the majority of whom were also unaware of being overweight.

Weight status and the perception of body image in men

PubMed Central

Gardner, Rick M

2014-01-01

Understanding the role of body size in relation to the accuracy of body image perception in men is an important topic because of the implications for avoiding and treating obesity, and it may serve as a potential diagnostic criterion for eating disorders. The early research on this topic produced mixed findings. About one-half of the early studies showed that obese men overestimated their body size, with the remaining half providing accurate estimates. Later, improvements in research technology and methodology provided a clearer indication of the role of weight status in body image perception. Research in our laboratory has also produced diverse findings, including that obese subjects sometimes overestimate their body size. However, when examining our findings across several studies, obese subjects had about the same level of accuracy in estimating their body size as normal-weight subjects. Studies in our laboratory also permitted the separation of sensory and nonsensory factors in body image perception. In all but one instance, no differences were found overall between the ability of obese and normal-weight subjects to detect overall changes in body size. Importantly, however, obese subjects are better at detecting changes in their body size when the image is distorted to be too thin as compared to too wide. Both obese and normal-weight men require about a 3%–7% change in the width of their body size in order to detect the change reliably. Correlations between a range of body mass index values and body size estimation accuracy indicated no relationship between these variables. Numerous studies in other laboratories asked men to place their body size into discrete categorizes, ranging from thin to obese. Researchers found that overweight and obese men underestimate their weight status, and that men are less accurate in their categorizations than are women. Cultural influences have been found to be important, with body size underestimations occurring in cultures where a larger body is found to be desirable. Methodological issues are reviewed with recommendations for future studies. PMID:25114606

Sexual orientation and shifts in preferences for a partner's body attributes in short-term versus long-term mating contexts.

PubMed

Lucas, Margery; Koff, Elissa; Grossmith, Samantha; Migliorini, Robyn

2011-06-01

This study assessed the effects of short- and long-term mating contexts on preferences for body characteristics of potential relationship partners in lesbians and heterosexual women. Lesbians (n = 41) rated figure drawings and computer-generated images of women that varied in body fat, waist-to-hip ratio, and breast size; heterosexual women (n = 95) rated computer-generated images of men that varied in muscularity and body fat. Both lesbians and heterosexual women showed a shift in preferences toward more physically attractive partners for shortterm relationships. All body aspects were affected, except that heterosexual women did not show a preference shift for male body fat. The results were interpreted in terms of a mating trade-off strategy in which mate preferences are the consequence of cost/benefit analyses and suggest that preferences for physical attributes of sexual partners may be shared by members of the same sex regardless of sexual orientation.

Effect of Intraperitoneal Radiotelemetry Instrumentation on Voluntary Wheel Running and Surgical Recovery in Mice

PubMed Central

Helwig, Bryan G; Ward, Jermaine A; Blaha, Michael D; Leon, Lisa R

2012-01-01

Radiotelemetry transmitters support tracking of physiologic variables in conscious animals, but the size of the transmitter may alter animal health and behavior. We hypothesized that the size of the device adversely affects body weight, food intake, water intake, circadian core temperature, activity, voluntary running patterns, and the health of internal organs and that these negative effects can be minimized with smaller transmitter devices. Male C57BL/6J mice (weight, 20 to 24 g) were implanted with small (1.1 g, 0.52 mL) or large (3.5 g, 1.75 mL) radiotransmitters. Recovery of presurgical body weight, food intake, and water intake occurred within 3 d in mice implanted with small transmitter and 9 d in those with large transmitters. Mice with small transmitters displayed robust circadian core body temperature and activity patterns within 1 d after surgery, whereas activity was depressed in mice with large transmitters throughout experimentation. The most robust effects of the large transmitter included significantly reduced voluntary running, which never recovered to baseline, and inflammation of the diaphragm, large intestine, and duodenum. These results demonstrate that the large transmitter delayed surgical recovery, disrupted normal growth, reduced voluntary running, and induced inflammatory reactions of the internal organs of mice. The choice of radiotelemetry transmitter can significantly affect the health and wellbeing of experimental mice as well as data quality, such that the smallest transmitter device available and appropriate to the situation should be chosen for experimentation. PMID:23312089

Body Image in Anorexia Nervosa: Body Size Estimation Utilising a Biological Motion Task and Eyetracking.

PubMed

Phillipou, Andrea; Rossell, Susan Lee; Gurvich, Caroline; Castle, David Jonathan; Troje, Nikolaus Friedrich; Abel, Larry Allen

2016-03-01

Anorexia nervosa (AN) is a psychiatric condition characterised by a distortion of body image. However, whether individuals with AN can accurately perceive the size of other individuals' bodies is unclear. In the current study, 24 women with AN and 24 healthy control participants undertook two biological motion tasks while eyetracking was performed: to identify the gender and to indicate the walkers' body size. Anorexia nervosa participants tended to 'hyperscan' stimuli but did not demonstrate differences in how visual attention was directed to different body areas, relative to controls. Groups also did not differ in their estimation of body size. The hyperscanning behaviours suggest increased anxiety to disorder-relevant stimuli in AN. The lack of group difference in the estimation of body size suggests that the AN group was able to judge the body size of others accurately. The findings are discussed in terms of body image distortion specific to oneself in AN. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

Body size in early life and risk of breast cancer.

PubMed

Shawon, Md Shajedur Rahman; Eriksson, Mikael; Li, Jingmei

2017-07-21

Body size in early life is inversely associated with adult breast cancer (BC) risk, but it is unclear whether the associations differ by tumor characteristics. In a pooled analysis of two Swedish population-based studies consisting of 6731 invasive BC cases and 28,705 age-matched cancer-free controls, we examined the associations between body size in early life and BC risk. Self-reported body sizes at ages 7 and 18 years were collected by a validated nine-level pictogram (aggregated into three categories: small, medium and large). Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated from multivariable logistic regression models in case-control analyses, adjusting for study, age at diagnosis, age at menarche, number of children, hormone replacement therapy, and family history of BC. Body size change between ages 7 and 18 were also examined in relation to BC risk. Case-only analyses were performed to test whether the associations differed by tumor characteristics. Medium or large body size at age 7 and 18 was associated with a statistically significant decreased BC risk compared to small body size (pooled OR (95% CI): comparing large to small, 0.78 (0.70-0.86), P trend <0.001 and 0.72 (0.64-0.80), P trend <0.001, respectively). The majority of the women (~85%) did not change body size categories between age 7 and 18 . Women who remained medium or large between ages 7 and 18 had significantly decreased BC risk compared to those who remained small. A reduction in body size between ages 7 and 18 was also found to be inversely associated with BC risk (0.90 (0.81-1.00)). No significant association was found between body size at age 7 and tumor characteristics. Body size at age 18 was found to be inversely associated with tumor size (P trend  = 0.006), but not estrogen receptor status and lymph node involvement. For all analyses, the overall inferences did not change appreciably after further adjustment for adult body mass index. Our data provide further support for a strong and independent inverse relationship between early life body size and BC risk. The association between body size at age 18 and tumor size could be mediated by mammographic density.

Maternal life course socio-economic position and offspring body composition at birth in a multi-ethnic population.

PubMed

Sletner, Line; Jenum, Anne Karen; Mørkrid, Kjersti; Vangen, Siri; Holme, Ingar M; Birkeland, Kåre I; Nakstad, Britt

2014-09-01

Size and body composition at birth may affect long-term health. Mean birthweight and body composition differ between ethnic groups living in Europe. We wanted to explore if this relates to differences in socio-economic conditions in country of origin and over the maternal life course. This is a population-based cohort study of healthy pregnant women living in Oslo, Norway. Data on maternal early life and present socio-economic position (SEP) were collected in early gestation, and SEP scores were extracted through two separate principal components analyses. The associations between maternal present SEP and four different offspring anthropometric measures at birth were assessed separately, stratified by maternal early life SEP (dichotomised score) and Human Development Index (HDI, a country-level socio-economic indicator) in the country of origin [high HDI (Reference), n = 287 and low HDI, n = 250]. A strong positive association between maternal present SEP and offspring birthweight was observed if maternal early life SEP was high, but not if maternal early life SEP was low (P < 0.001 for the interaction term). This interactional effect was observed in both HDI groups. Maternal life course SEP affected offspring birthweight mainly through an effect on length and sum of skin folds. Offspring of mothers with origin from low HDI countries had smaller abdominal circumference, possibly indicating less fat-free mass, regardless of maternal life course SEP. Our results suggest that there are transgenerational effects of maternal past socio-economic conditions on offspring size and body composition at birth that modify the associations with present socio-economic factors. © 2014 John Wiley & Sons Ltd.

Effect of Carbohydrate Supplementation on Investment into Offspring Number, Size, and Condition in a Social Insect

PubMed Central

Wills, Bill D.; Chong, Cody D.; Wilder, Shawn M.; Eubanks, Micky D.; Holway, David A.; Suarez, Andrew V.

2015-01-01

Resource availability can determine an organism’s investment strategies for growth and reproduction. When nutrients are limited, there are potential tradeoffs between investing into offspring number versus individual offspring size. In social insects, colony investment in offspring size and number may shift in response to colony needs and the availability of food resources. We experimentally manipulated the diet of a polymorphic ant species (Solenopsis invicta) to test how access to the carbohydrate and amino acid components of nectar resources affect colony investment in worker number, body size, size distributions, and individual percent fat mass. We reared field-collected colonies on one of four macronutrient treatment supplements: water, amino acids, carbohydrates, and amino acid and carbohydrates. Having access to carbohydrates nearly doubled colony biomass after 60 days. This increase in biomass resulted from an increase in worker number and mean worker size. Access to carbohydrates also altered worker body size distributions. Finally, we found a negative relationship between worker number and size, suggesting a tradeoff in colony investment strategies. This tradeoff was more pronounced for colonies without access to carbohydrate resources. The monopolization of plant-based resources has been implicated in the ecological success of ants. Our results shed light on a possible mechanism for this success, and also have implications for the success of introduced species. In addition to increases in colony size, our results suggest that having access to plant-based carbohydrates can also result in larger workers that may have better individual fighting ability, and that can withstand greater temperature fluctuations and periods of food deprivation. PMID:26196147

Larval nutrition differentially affects adult fitness and Plasmodium development in the malaria vectors Anopheles gambiae and Anopheles stephensi

PubMed Central

2013-01-01

Background Mosquito fitness is determined largely by body size and nutritional reserves. Plasmodium infections in the mosquito and resultant transmission of malaria parasites might be compromised by the vector’s nutritional status. We studied the effects of nutritional stress and malaria parasite infections on transmission fitness of Anopheles mosquitoes. Methods Larvae of Anopheles gambiae sensu stricto and An. stephensi were reared at constant density but with nutritionally low and high diets. Fitness of adult mosquitoes resulting from each dietary class was assessed by measuring body size and lipid, protein and glycogen content. The size of the first blood meal was estimated by protein analysis. Mosquitoes of each dietary class were fed upon a Plasmodium yoelii nigeriensis-infected mouse, and parasite infections were determined 5 d after the infectious blood meal by dissection of the midguts and by counting oocysts. The impact of Plasmodium infections on gonotrophic development was established by dissection. Results Mosquitoes raised under low and high diets emerged as adults of different size classes comparable between An. gambiae and An. stephensi. In both species low-diet females contained less protein, lipid and glycogen upon emergence than high-diet mosquitoes. The quantity of larval diet impacted strongly upon adult blood feeding and reproductive success. The prevalence and intensity of P. yoelii nigeriensis infections were reduced in low-diet mosquitoes of both species, but P. yoelii nigeriensis impacted negatively only on low-diet, small-sized An. gambiae considering survival and egg maturation. There was no measurable fitness effect of P. yoelii nigeriensis on An. stephensi. Conclusions Under the experimental conditions, small-sized An. gambiae expressed high mortality, possibly caused by Plasmodium infections, the species showing distinct physiological concessions when nutrionally challenged in contrast to well-fed, larger siblings. Conversely, An. stephensi was a robust, successful vector regardless of its nutrional status upon emergence. The data suggest that small-sized An. gambiae, therefore, would contribute little to malaria transmission, whereas this size effect would not affect An. stephensi. PMID:24326030

Effect of mature body weight and stocking rate on cow and calf performance, cow herd efficiency, and economics in the southeastern United States.

PubMed

Beck, P A; Stewart, C B; Gadberry, M S; Haque, M; Biermacher, J

2016-04-01

Eight 4-ha mixed warm-season grass pastures in southwestern Arkansas (33°40'4″ N, 93°35'24″ W, and elevation 107 m) were stocked with either large mature size (571 kg [SD 55.2] BW) or small mature size (463 kg [SD 58.2] BW) spring-calving cows at 4 stocking rates (SR; 1, 1.5, 2, or 2.5 cow-calf pairs/ha) over 4 yr to test the effects of SR and mature body size on cow and calf performance and system economics. Each pasture received 112 kg/ha N as ammonium nitrate in May and was broadcast seeded to annual ryegrass ( Lam.) in mid October each fall along with 112 kg/ha N as ammonium nitrate. Data were analyzed by regression to determine the effects of cow size and SR on calf performance, cow BW change, calf gain, weaning weight per hectare, hay feeding requirements, and net returns. As SR increased, cow BW and BCS at weaning decreased ( < 0.01) by 26 kg and 0.36 condition scores, respectively, for each additional cow stocked per hectare ( = 0.44). Calf BW at weaning in October increased ( < 0.01) 19 kg for each 100-kg increase in cow BW but was not affected ( = 0.66) by SR. As cow BW increased, calf BW at weaning per 100 kg cow BW decreased ( < 0.01) 6.7 kg for each 100-kg increase in cow BW but was not affected ( = 0.44) by SR. Neither cow BW nor SR affected ( ≥ 0.53) pregnancy percentage, which averaged 88% over the 4-yr experiment. Calf BW weaned per hectare was not affected ( = 0.75) by cow BW but linearly increased ( < 0.01) by 217 kg for each additional cow per hectare SR. Hay feeding days and cost of hay per cow increased ( ≤ 0.05) and kilograms of hay offered per cow tended ( = 0.09) to linearly increase with increasing SR, yet cow BW had no effects ( > 0.22). Although there were no effects ( ≥ 0.38) of cow BW on carrying cost or net returns, increasing SR decreased ( < 0.01) total expenses by US$102/cow and increased net returns by $70/cow and $438/ha for each cow per hectare increase in SR. These data indicate that increasing cow size can increase weaning BW of calves but does not affect total production per hectare or profitability, even though weaning weight efficiency ratios were reduced. Increasing SR reduced cow BW and BCS at weaning and increased feeding of conserved forages but did not affect pregnancy rates and led to increases in total calf BW weaned per hectare and net returns.

Prey availability affects territory size, but not territorial display behavior, in green anole lizards

NASA Astrophysics Data System (ADS)

Stehle, Chelsea M.; Battles, Andrew C.; Sparks, Michelle N.; Johnson, Michele A.

2017-10-01

The availability of food resources can affect the size and shape of territories, as well as the behaviors used to defend territories, in a variety of animal taxa. However, individuals within a population may respond differently to variation in food availability if the benefits of territoriality vary among those individuals. For example, benefits to territoriality may differ for animals of differing sizes, because larger individuals may require greater territory size to acquire required resources, or territorial behavior may differ between the sexes if males and females defend different resources in their territories. In this study, we tested whether arthropod abundance and biomass were associated with natural variation in territory size and defense in insectivorous green anole lizards, Anolis carolinensis. Our results showed that both male and female lizards had smaller territories in a habitat with greater prey biomass than lizards in habitats with less available prey, but the rates of aggressive behaviors used to defend territories did not differ among these habitats. Further, we did not find a relationship between body size and territory size, and the sexes did not differ in their relationships between food availability and territory size or behavioral defense. Together, these results suggest that differences in food availability influenced male and female territorial strategies similarly, and that territory size may be more strongly associated with variation in food resources than social display behavior. Thus, anole investment in the behavioral defense of a territory may not vary with territory quality.

Contrasting effects of climate on juvenile body size in a Southern Hemisphere passerine bird.

PubMed

Kruuk, Loeske E B; Osmond, Helen L; Cockburn, Andrew

2015-08-01

Despite extensive research on the topic, it has been difficult to reach general conclusions as to the effects of climate change on morphology in wild animals: in particular, the effects of warming temperatures have been associated with increases, decreases or stasis in body size in different populations. Here, we use a fine-scale analysis of associations between weather and offspring body size in a long-term study of a wild passerine bird, the cooperatively breeding superb fairy-wren, in south-eastern Australia to show that such variation in the direction of associations occurs even within a population. Over the past 26 years, our study population has experienced increased temperatures, increased frequency of heatwaves and reduced rainfall - but the mean body mass of chicks has not changed. Despite the apparent stasis, mass was associated with weather across the previous year, but in multiple counteracting ways. Firstly, (i) chick mass was negatively associated with extremely recent heatwaves, but there also positive associations with (ii) higher maximum temperatures and (iii) higher rainfall, both occurring in a period prior to and during the nesting period, and finally (iv) a longer-term negative association with higher maximum temperatures following the previous breeding season. Our results illustrate how a morphological trait may be affected by both short- and long-term effects of the same weather variable at multiple times of the year and that these effects may act in different directions. We also show that climate within the relevant time windows may not be changing in the same way, such that overall long-term temporal trends in body size may be minimal. Such complexity means that analytical approaches that search for a single 'best' window for one particular weather variable may miss other relevant information, and is also likely to make analyses of phenotypic plasticity and prediction of longer-term population dynamics difficult. © 2015 John Wiley & Sons Ltd.

Developmental lead exposure has mixed effects on butterfly cognitive processes.

PubMed

Philips, Kinsey H; Kobiela, Megan E; Snell-Rood, Emilie C

2017-01-01

While the effects of lead pollution have been well studied in vertebrates, it is unclear to what extent lead may negatively affect insect cognition. Lead pollution in soils can elevate lead in plant tissues, suggesting it could negatively affect neural development of insect herbivores. We used the cabbage white butterfly (Pieris rapae) as a model system to study the effect of lead pollution on insect cognitive processes, which play an important role in how insects locate and handle resources. Cabbage white butterfly larvae were reared on a 4-ppm lead diet, a concentration representative of vegetation in polluted sites; we measured eye size and performance on a foraging assay in adults. Relative to controls, lead-reared butterflies did not differ in time or ability to search for a food reward associated with a less preferred color. Indeed, lead-treated butterflies were more likely to participate in the behavioral assay itself. Lead exposure did not negatively affect survival or body size, and it actually sped up development time. The effects of lead on relative eye size varied with sex: lead tended to reduce eye size in males, but increase eye size in females. These results suggest that low levels of lead pollution may have mixed effects on butterfly vision, but only minimal impacts on performance in foraging tasks, although follow-up work is needed to test whether this result is specific to cabbage whites, which are often associated with disturbed areas.

The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size

PubMed Central

Rideout, Elizabeth J.; Narsaiya, Marcus S.; Grewal, Savraj S.

2015-01-01

Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway. PMID:26710087

The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size.

PubMed

Rideout, Elizabeth J; Narsaiya, Marcus S; Grewal, Savraj S

2015-12-01

Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.

Migrate small, sound big: functional constraints on body size promote tracheal elongation in cranes.

PubMed

Jones, M R; Witt, C C

2014-06-01

Organismal traits often represent the outcome of opposing selection pressures. Although social or sexual selection can cause the evolution of traits that constrain function or survival (e.g. ornamental feathers), it is unclear how the strength and direction of selection respond to ecological shifts that increase the severity of the constraint. For example, reduced body size might evolve by natural selection to enhance flight performance in migratory birds, but social or sexual selection favouring large body size may provide a countervailing force. Tracheal elongation is a potential outcome of these opposing pressures because it allows birds to convey an auditory signal of exaggerated body size. We predicted that the evolution of migration in cranes has coincided with a reduction in body size and a concomitant intensification of social or sexual selection for apparent large body size via tracheal elongation. We used a phylogenetic comparative approach to examine the relationships among migration distance, body mass and trachea length in cranes. As predicted, we found that migration distance correlated negatively with body size and positively with proportional trachea length. This result was consistent with our hypothesis that evolutionary reductions in body size led to intensified selection for trachea length. The most likely ultimate causes of intensified positive selection on trachea length are the direct benefits of conveying a large body size in intraspecific contests for mates and territories. We conclude that the strength of social or sexual selection on crane body size is linked to the degree of functional constraint. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Fetal size in mid- and late pregnancy is related to infant alertness: the generation R study.

PubMed

Henrichs, Jens; Schenk, Jacqueline J; Schmidt, Henk G; Arends, Lidia R; Steegers, Eric A P; Hofman, Albert; Jaddoe, Vincent W V; Verhulst, Frank C; Tiemeier, Henning

2009-03-01

The vulnerability for behavioral problems is partly shaped in fetal life. Numerous studies have related indicators of intrauterine growth, for example, birth weight and body size, to behavioral development. We investigated whether fetal size in mid- and late pregnancy is related to infant irritability and alertness. In a population-based birth cohort of 4,255 singleton full-term infants ultrasound measurements of fetal head and abdominal circumference in mid- and late pregnancy were performed. Infant irritability and alertness scores were obtained by the Mother and Baby Scales at 3 months and z-standardized. Multiple linear regression analyses revealed curvilinear associations (inverted J-shape) of measures of fetal size in both mid- and late pregnancy with infant alertness. Fetal size characteristics were not associated with infant irritability. These results suggest that alterations of intrauterine growth affecting infant alertness are already detectable from mid-pregnancy onwards.

Predator size divergence depends on community context.

PubMed

Okuzaki, Yutaka; Sota, Teiji

2018-05-09

Body size is a multi-functional trait related to various fitness components, but the relative importance of different selection pressures is seldom resolved. In Carabus japonicus beetles, of which the larvae exclusively prey on earthworms, adult body size is related to the presence/absence of a larger congener and habitat temperature. In sympatry, C. japonicus consistently exhibits smaller body size which is effective for avoiding interspecific mating, but in allopatry, it shows size variation unrelated to temperature. Here, we show that this predator-size variation is attributed to prey-size variation, associated with high phylogenetic diversity in earthworm communities. In allopatry, the predator size was larger where larger prey occurred. Larger adult size may have been selected because larger females produce larger larvae, which can subdue larger prey. Thus, in the absence of a larger congener, variation in prey body size had a pronounced effect on geographic body size divergence in C. japonicus. © 2018 John Wiley & Sons Ltd/CNRS.

Influence of Xenorhabdus (Gamma-Proteobacteria: Enterobacteriaceae) symbionts on gonad postembryonic development in Steinernema (Nematoda: Steinernematidae) nematodes.

PubMed

Roder, Alexandra C; Stock, S Patricia

2018-03-01

Steinernema nematodes and their Xenorhabdus partners form an obligate mutualistic association. This partnership is insecticidal to a wide range of insects. Steinernema rely on their Xenorhabdus partner to produce toxins inside the insect cadaver to liberate nutrients from the insect, as well as antimicrobials to sterilize the cadaver, thus creating a suitable environment for reproduction. In return, Steinernema vector their Xenorhabdus between insect hosts. Disruption of this partnership may affect the success of both partners. For instance, when Steinernema associates with non-cognate symbionts, their virulence and reproductive fitness are affected. In this study, we examined the effect of symbiotic (cognate and non-cognate) and non-symbiotic bacteria on maturation time, gonad postembryonic development, and sex ratio of first-generation Steinernema adults. Two Steinernema spp. were considered: S. feltiae SN and S. carpocapsae All. In vitro assays were carried out by pairing each nematode sp. with symbiotic (cognate and non-cognate) Xenorhabdus, and with non-symbiotic bacteria (Serratia proteamaculans). Additionally, for comparative purposes, we also considered adult nematodes reared in vivo in Galleria mellonella larvae to assess nematode development under natural conditions. Results from this study showed non-symbiotic Serratia proteamaculans did not support adult development of S. feltiae but it allowed development of S. carpocapsae adults. Sex ratio decreased from 2:1 to 1:1 (female: male) when S. carpocapsae adults were reared with the non-symbiotic S. proteamaculans. Cognate or non-cognate Xenorhabdus spp. and/or strains did not change the sex ratio of any of either Steinernema spp. tested. Morphometric analysis also revealed that bacterial conditions influenced adult size and gonad postembryonic development in both Steinernema species. Body size (length and width), and gonad length in both S. feltiae males and females, were significantly reduced when reared with a non-cognate Xenorhabdus species. In S. carpocapsae, males exhibited an enhanced body size (length and width) and gonad length when reared with a non-cognate X. nematophila strain. S. carpocapsae females also exhibited an enhanced gonad length when reared with a non-cognate X. nematophila strain. S. carpocapsae males and females were underdeveloped when reared with the non-symbiotic S. proteamaculans, and exhibited reduced body sizes and gonad lengths. We conclude that development of first-generation adults of both Steinernema spp. tested, in particular time to adult maturation as well as body and gonad size were directly influenced by the bacterial symbionts they were cultured with. However, response to the culture conditions was species specific. Published by Elsevier Inc.

Effects of newborn characteristics and length of colostrum feeding period on passive immune transfer in goat kids.

PubMed

Castro, N; Capote, J; Morales-Delanuez, A; Rodríguez, C; Argüello, A

2009-04-01

Majorera goat kids (n = 200) were used to evaluate the effects of litter size, birth body weight, sex, and suckling duration on serum IgG concentrations. Kids were assigned to 1 of 3 experimental groups: litter size and sex were equally distributed in each group. In the first group, kids (n = 67) stayed with their dams for 24 h; in the second group, kids (n = 66) stayed with their dams for 48 h; and in the third group, kids (n = 67) stayed with their dams for 120 h. Blood samples were obtained every 24 h for 5 d, and serum IgG concentration was measured using radial immunodiffusion. In litter sizes of 1 to 2 kids, IgG blood serum concentration was significantly higher (18.30 +/- 5.40 mg/mL) than in litters of 3 kids (9.85 +/- 4.23 mg/mL). Kid sex did not affect IgG blood serum concentrations. Suckling duration did not affect kid serum IgG concentrations. In conclusion, kids with low birth body weight (<2.8 kg) or from litters of 3 may need special attention. If newborn goat kids are allowed to suckle colostrum for at least 24 h from their dams, this seems to be sufficient time to ingest enough IgG from colostrum to achieve an adequate serum IgG concentration and passive immune protection to avoid failure of passive immune transfer.

Annual plants change in size over a century of observations.

PubMed

Leger, Elizabeth A

2013-07-01

Studies have documented changes in animal body sizes over the last century, but very little is known about changes in plant sizes, even though reduced plant productivity is potentially responsible for declines in size of other organisms. Here, I ask whether warming trends in the Great Basin have affected plant size by measuring specimens preserved on herbarium sheets collected between 1893 and 2011. I asked how maximum and minimum temperatures, precipitation, and the Pacific Decadal Oscillation (PDO) in the year of collection affected plant height, leaf size, and flower number, and asked whether changes in climate resulted in decreasing sizes for seven annual forbs. Species had contrasting responses to climate factors, and would not necessarily be expected to respond in parallel to climatic shifts. There were generally positive relationships between plant size and increased minimum and maximum temperatures, which would have been predicted to lead to small increases in plant sizes over the observation period. While one species increased in size and flower number over the observation period, five of the seven species decreased in plant height, four of these decreased in leaf size, and one species also decreased in flower production. One species showed no change. The mechanisms behind these size changes are unknown, and the limited data available on these species (germination timing, area of occupancy, relative abundance) did not explain why some species shrank while others grew or did not change in size over time. These results show that multiple annual forbs are decreasing in size, but that even within the same functional group, species may have contrasting responses to similar environmental stimuli. Changes in plant size could have cascading effects on other members of these communities, and differential responses to directional change may change the composition of plant communities over time. © 2013 Blackwell Publishing Ltd.

Body Size Evolution in Insular Speckled Rattlesnakes (Viperidae: Crotalus mitchellii)

PubMed Central

Meik, Jesse M.; Lawing, A. Michelle; Pires-daSilva, André

2010-01-01

Background Speckled rattlesnakes (Crotalus mitchellii) inhabit multiple islands off the coast of Baja California, Mexico. Two of the 14 known insular populations have been recognized as subspecies based primarily on body size divergence from putative mainland ancestral populations; however, a survey of body size variation from other islands occupied by these snakes has not been previously reported. We examined body size variation between island and mainland speckled rattlesnakes, and the relationship between body size and various island physical variables among 12 island populations. We also examined relative head size among giant, dwarfed, and mainland speckled rattlesnakes to determine whether allometric differences conformed to predictions of gape size (and indirectly body size) evolving in response to shifts in prey size. Methodology/Principal Findings Insular speckled rattlesnakes show considerable variation in body size when compared to mainland source subspecies. In addition to previously known instances of gigantism on Ángel de la Guarda and dwarfism on El Muerto, various degrees of body size decrease have occurred frequently in this taxon, with dwarfed rattlesnakes occurring mostly on small, recently isolated, land-bridge islands. Regression models using the Akaike information criterion (AIC) showed that mean SVL of insular populations was most strongly correlated with island area, suggesting the influence of selection for different body size optima for islands of different size. Allometric differences in head size of giant and dwarf rattlesnakes revealed patterns consistent with shifts to larger and smaller prey, respectively. Conclusions/Significance Our data provide the first example of a clear relationship between body size and island area in a squamate reptile species; among vertebrates this pattern has been previously documented in few insular mammals. This finding suggests that selection for body size is influenced by changes in community dynamics that are related to graded differences in area over what are otherwise similar bioclimatic conditions. We hypothesize that in this system shifts to larger prey, episodic saturation and depression of primary prey density, and predator release may have led to insular gigantism, and that shifts to smaller prey and increased reproductive efficiency in the presence of intense intraspecific competition may have led to insular dwarfism. PMID:20209105

Development and growth of fruit bodies and crops of the button mushroom, Agaricus bisporus.

PubMed

Straatsma, Gerben; Sonnenberg, Anton S M; van Griensven, Leo J L D

2013-10-01

We studied the appearance of fruit body primordia, the growth of individual fruit bodies and the development of the consecutive flushes of the crop. Relative growth, measured as cap expansion, was not constant. It started extremely rapidly, and slowed down to an exponential rate with diameter doubling of 1.7 d until fruit bodies showed maturation by veil breaking. Initially many outgrowing primordia were arrested, indicating nutritional competition. After reaching 10 mm diameter, no growth arrest occurred; all growing individuals, whether relatively large or small, showed an exponential increase of both cap diameter and biomass, until veil breaking. Biomass doubled in 0.8 d. Exponential growth indicates the absence of competition. Apparently there exist differential nutritional requirements for early growth and for later, continuing growth. Flushing was studied applying different picking sizes. An ordinary flushing pattern occurred at an immature picking size of 8 mm diameter (picking mushrooms once a day with a diameter above 8 mm). The smallest picking size yielded the highest number of mushrooms picked, confirming the competition and arrested growth of outgrowing primordia: competition seems less if outgrowing primordia are removed early. The flush duration (i.e. between the first and last picking moments) was not affected by picking size. At small picking size, the subsequent flushes were not fully separated in time but overlapped. Within 2 d after picking the first individuals of the first flush, primordia for the second flush started outgrowth. Our work supports the view that the acquisition of nutrients by the mycelium is demand rather than supply driven. For formation and early outgrowth of primordia, indications were found for an alternation of local and global control, at least in the casing layer. All these data combined, we postulate that flushing is the consequence of the depletion of some unknown specific nutrition required by outgrowing primordia. Copyright © 2013 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Can the Yarkovsky effect significantly influence the main-belt size distribution?

NASA Astrophysics Data System (ADS)

O'Brien, D. P.; Greenberg, R.

2001-11-01

It has been proposed that the size distribution of main-belt asteroids may be significantly modified by the Yarkovsky effect---a size-dependent radiation force which can sweep asteroids into resonances and out of the main belt. Bell [1] suggested that this effect could deplete the population of asteroids smaller than ~10 m by at least an order of magnitude, resulting in the lack of small craters observed on Eros. Others have hypothesized that the same effect could explain the steepness of the crater distribution on Gaspra [2]. We have explicitly included Yarkovsky removal in a numerical collisional evolution model. The algorithm uses recent calculations of the expected removal rates of different sized bodies from the main belt (David Vokrouhlicky, personal communication). We find that the rate of removal of bodies from the main belt by the Yarkovsky effect may be within an order of magnitude of the rate of collisional destruction for asteroids ~10 m in diameter, and negligible for larger or smaller asteroids. When Yarkovsky removal is incorporated into our numerical collisional evolution model, the numbers of bodies ~10 m in diameter is reduced by ~10-20%, and a wave propagates up the size distribution increasing the number of bodies ~300 m by ~10%. This `waviness' could conceivably be detected in the cratering records on asteroids. However, the uncertainties in crater counts on Ida, Gaspra, Malthide, and Eros are >10% for diameters >100 m (i. e. the craters made by impactors >10 m in diameter). Contrary to the earlier hypothesis, Yarkovsky removal of small asteroids cannot have substantially affected the overall slopes of the crater populations on these asteroids. Moreover, Yarkovsky removal cannot explain the lack of small (<10 m) craters on Eros, because the corresponding impactors (<1 m) are unaffected by the Yarkovsky effect. [1] Bell, J. F. (2001). LPSC XXXII abstract no. 1964. [2] Hartmann, W. K. and E. V. Ryan (1996). DPS 28, abstract no. 10.35.

Global warming may disproportionately affect larger adults in a predatory coral reef fish.

PubMed

Messmer, Vanessa; Pratchett, Morgan S; Hoey, Andrew S; Tobin, Andrew J; Coker, Darren J; Cooke, Steven J; Clark, Timothy D

2017-06-01

Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems. © 2016 John Wiley & Sons Ltd.

Ideal Body Size as a Mediator for the Gender-Specific Association Between Socioeconomic Status and Body Mass Index: Evidence From an Upper-Middle-Income Country in the African Region.

PubMed

Yepes, Maryam; Maurer, Jürgen; Stringhini, Silvia; Viswanathan, Barathi; Gedeon, Jude; Bovet, Pascal

2016-04-01

While obesity continues to rise globally, the associations between body size, gender, and socioeconomic status (SES) seem to vary in different populations, and little is known on the contribution of perceived ideal body size in the social disparity of obesity in African countries. We examined the gender and socioeconomic patterns of body mass index (BMI) and perceived ideal body size in the Seychelles, a middle-income small island state in the African region. We also assessed the potential role of perceived ideal body size as a mediator for the gender-specific association between SES and BMI. A population-based survey of 1,240 adults aged 25 to 64 years conducted in December 2013. Participants' BMI was calculated based on measured weight and height; ideal body size was assessed using a nine-silhouette instrument. Three SES indicators were considered: income, education, and occupation. BMI and perceived ideal body size were both higher among men of higher versus lower SES (p< .001) but lower among women of higher versus lower SES (p< .001), irrespective of the SES indicator used. Multivariate analysis showed a strong and direct association between perceived ideal body size and BMI in both men and women (p< .001) and was consistent with a potential mediating role of perceived ideal body size in the gender-specific associations between SES and BMI. Our study emphasizes the importance of gender and socioeconomic differences in BMI and ideal body size and suggests that public health interventions that promote perception of healthy weight could help mitigate SES-related disparities in BMI. © 2016 Society for Public Health Education.

Body mass estimates of hominin fossils and the evolution of human body size.

PubMed

Grabowski, Mark; Hatala, Kevin G; Jungers, William L; Richmond, Brian G

2015-08-01

Body size directly influences an animal's place in the natural world, including its energy requirements, home range size, relative brain size, locomotion, diet, life history, and behavior. Thus, an understanding of the biology of extinct organisms, including species in our own lineage, requires accurate estimates of body size. Since the last major review of hominin body size based on postcranial morphology over 20 years ago, new fossils have been discovered, species attributions have been clarified, and methods improved. Here, we present the most comprehensive and thoroughly vetted set of individual fossil hominin body mass predictions to date, and estimation equations based on a large (n = 220) sample of modern humans of known body masses. We also present species averages based exclusively on fossils with reliable taxonomic attributions, estimates of species averages by sex, and a metric for levels of sexual dimorphism. Finally, we identify individual traits that appear to be the most reliable for mass estimation for each fossil species, for use when only one measurement is available for a fossil. Our results show that many early hominins were generally smaller-bodied than previously thought, an outcome likely due to larger estimates in previous studies resulting from the use of large-bodied modern human reference samples. Current evidence indicates that modern human-like large size first appeared by at least 3-3.5 Ma in some Australopithecus afarensis individuals. Our results challenge an evolutionary model arguing that body size increased from Australopithecus to early Homo. Instead, we show that there is no reliable evidence that the body size of non-erectus early Homo differed from that of australopiths, and confirm that Homo erectus evolved larger average body size than earlier hominins. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Two-Tier Golgi-Based Control of Organelle Size Underpins the Functional Plasticity of Endothelial Cells

PubMed Central

Ferraro, Francesco; Kriston-Vizi, Janos; Metcalf, Daniel J.; Martin-Martin, Belen; Freeman, Jamie; Burden, Jemima J.; Westmoreland, David; Dyer, Clare E.; Knight, Alex E.; Ketteler, Robin; Cutler, Daniel F.

2014-01-01

Summary Weibel-Palade bodies (WPBs), endothelial-specific secretory granules that are central to primary hemostasis and inflammation, occur in dimensions ranging between 0.5 and 5 μm. How their size is determined and whether it has a functional relevance are at present unknown. Here, we provide evidence for a dual role of the Golgi apparatus in controlling the size of these secretory carriers. At the ministack level, cisternae constrain the size of nanostructures (“quanta”) of von Willebrand factor (vWF), the main WPB cargo. The ribbon architecture of the Golgi then allows copackaging of a variable number of vWF quanta within the continuous lumen of the trans-Golgi network, thereby generating organelles of different sizes. Reducing the WPB size abates endothelial cell hemostatic function by drastically diminishing platelet recruitment, but, strikingly, the inflammatory response (the endothelial capacity to engage leukocytes) is unaltered. Size can thus confer functional plasticity to an organelle by differentially affecting its activities. PMID:24794632

Sex- and concentration-dependent effects of predator feces on seasonal regulation of body mass in the bank vole Clethrionomys glareolus.

PubMed

Tidhar, Wendy L; Bonier, Frances; Speakman, John R

2007-11-01

Increased perception of predation risk can cause changes in activity, feeding and reproductive behavior in a wide range of taxa. Many small mammals in the temperate zone exhibit fluctuations in body mass in response to changing photoperiod. Bank voles lose body mass in winter which they regain when photoperiod increases in the spring. To determine if predation risk affects seasonal changes in body mass (BM), bank voles were exposed to two concentrations (low: LC and high: HC) of weasel feces. Food intake (FI) and daily energy expenditure (DEE) were measured to establish if differences in body mass were due to adjustment in energy intake or expenditure. Fecal corticosterone (CORT) was measured to assess whether the voles had detected and responded to predator feces as a physiological stressor. Voles of both sexes had higher levels of fecal CORT in the groups exposed to weasel feces compared to controls. Voles responded to the predator feces in a sex- and concentration-dependent manner. Males responded to LC feces by gaining less mass following the change in photoperiod. This was mediated by reduced FI and higher DEE. Female voles also gained less BM in response to HC feces, but increased both FI and DEE. We hypothesize that males may gain a short-term advantage by lowering BM in response to predation risk, which may be regained without affecting reproductive success. The consequences of mass loss in females may be more significant as this may delay the onset of breeding or reduce the size or number of young, thereby negatively affecting breeding success.

The role of underestimating body size for self-esteem and self-efficacy among grade five children in Canada.

PubMed

Maximova, Katerina; Khan, Mohammad K A; Austin, S Bryn; Kirk, Sara F L; Veugelers, Paul J

2015-10-01

Underestimating body size hinders healthy behavior modification needed to prevent obesity. However, initiatives to improve body size misperceptions may have detrimental consequences on self-esteem and self-efficacy. Using sex-specific multiple mixed-effect logistic regression models, we examined the association of underestimating versus accurate body size perceptions with self-esteem and self-efficacy in a provincially representative sample of 5075 grade five school children. Body size perceptions were defined as the standardized difference between the body mass index (BMI, from measured height and weight) and self-perceived body size (Stunkard body rating scale). Self-esteem and self-efficacy for physical activity and healthy eating were self-reported. Most of overweight boys and girls (91% and 83%); and most of obese boys and girls (93% and 90%) underestimated body size. Underestimating weight was associated with greater self-efficacy for physical activity and healthy eating among normal-weight children (odds ratio: 1.9 and 1.6 for boys, 1.5 and 1.4 for girls) and greater self-esteem among overweight and obese children (odds ratio: 2.0 and 6.2 for boys, 2.0 and 3.4 for girls). Results highlight the importance of developing optimal intervention strategies as part of targeted obesity prevention efforts that de-emphasize the focus on body weight, while improving body size perceptions. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of body mass and melanism on heat balance in Liolaemus lizards of the goetschi clade.

PubMed

Moreno Azócar, Débora Lina; Bonino, Marcelo Fabián; Perotti, María Gabriela; Schulte, James A; Abdala, Cristian Simón; Cruz, Félix Benjamín

2016-04-15

The body temperature of ectotherms depends on the environmental temperatures and behavioral adjustments, but morphology may also have an effect. For example, in colder environments, animals tend to be larger and to show higher thermal inertia, as proposed by Bergmann's rule and the heat balance hypothesis (HBH). Additionally, dark coloration increases solar radiation absorption and should accelerate heat gain (thermal melanism hypothesis, TMH). We tested Bergmann's rule, the HBH and the TMH within the ITALIC! Liolaemus goetschilizard clade, which shows variability in body size and melanic coloration. We measured heating and cooling rates of live and euthanized animals, and tested how morphology and color affect these rates. Live organisms show less variable and faster heating rates compared with cooling rates, suggesting behavioral and/or physiological adjustments. Our results support Bergmann's rule and the HBH, as larger species show slower heating and cooling rates. However, we did not find a clear pattern to support the TMH. The influence of dorsal melanism on heating by radiation was masked by the body size effect in live animals, and results from euthanized individuals also showed no clear effects of melanism on heating rates. Comparison among three groups of live individuals with different degrees of melanism did not clarify the influence of melanism on heating rates. However, when euthanized animals from the same three groups were compared, we observed that darker euthanized animals actually heat faster than lighter ones, favoring the TMH. Although unresolved aspects remain, body size and coloration influenced heat exchange, suggesting complex thermoregulatory strategies in these lizards, probably regulated through physiology and behavior, which may allow these small lizards to inhabit harsh weather environments. © 2016. Published by The Company of Biologists Ltd.

Effects of leptin replacement alone and with exendin-4 on food intake and weight regain in weight-reduced diet-induced obese rats

PubMed Central

Haver, Alvin; Chelikani, Prasanth K.; Apenteng, Bettye; Perriotte-Olson, Curtis; Anders, Krista; Steenson, Sharalyn; Blevins, James E.

2012-01-01

Weight loss in obese humans produces a relative leptin deficiency, which is postulated to activate potent orexigenic and energy conservation mechanisms to restrict weight loss and promote weight regain. Here we determined whether leptin replacement alone or with GLP-1 receptor agonist exendin-4 attenuates weight regain or promotes greater weight loss in weight-reduced diet-induced obese (DIO) rats. Forty percent restriction in daily intake of a high-fat diet in DIO rats for 4 wk reduced body weight by 12%, body fat by 29%, and plasma leptin by 67% and normalized leptin sensitivity. When food restriction ended, body weight, body fat, and plasma leptin increased rapidly. Daily administration of leptin [3-h intraperitoneal (ip) infusions (4 nmol·kg−1·h−1)] at onset and end of dark period for 3 wk did not attenuate hyperphagia and weight regain, nor did it affect mean daily meal sizes or meal numbers. Exendin-4 (50 pmol·kg−1·h−1) infusions during the same intervals prevented postrestriction hyperphagia and weight regain by normalizing meal size. Coadministration of leptin and exendin-4 did not reduce body weight more than exendin-4 alone. Instead, leptin began to attenuate the inhibitory effects of exendin-4 on food intake, meal size, and weight regain by the end of the second week of administration. Plasma leptin in rats receiving leptin was sevenfold greater than in rats receiving vehicle and 17-fold greater than in rats receiving exendin-4. Together, these results do not support the hypothesis that leptin replacement alone or with exendin-4 attenuates weight regain or promotes greater weight loss in weight-reduced DIO rats. PMID:22510712

Micromégas: Altered Body-Environment Scaling in Literary Fiction.

PubMed

Dieguez, Sebastian

2016-01-01

Architectonic embodiment postulates a bidirectional link between bodily awareness and the architectural environment. The standard size and features of the human body, for instance, are thought to influence the structure of interiors and buildings, as well as their perception and appreciation. Whereas architectural practice and theory, the visual arts and more recently the cognitive sciences have explored this relationship of humans with their crafted environments, many fictional literary works have long experimented with alterations of body-environment scaling. This so-called Gulliver theme - popular in the science-fiction genre but also in children's literature and philosophical satire - reveals, as a recurrent thought-experiment, our preoccupation with proportions and our fascination for the infinitely small and large. Here I provide an overview of the altered scaling theme in literature, including classics such as Voltaire's Micromégas, Swift's Gulliver's Travels, Caroll's Alice, and Matheson's The Shrinking man, closely examining issues relevant to architectonic embodiment such as: bodily, perceptual, cognitive, affective, and social changes related to alterations in body size relative to people, objects and architectural environments. I next provide a taxonomy of the Gulliver theme and highlight its main psychological features, and then proceed to review relevant work from cognitive science. Although fictional alterations of body-environment scaling far outreach current possibilities in experimental research, I argue that the peripetiae and morals outlined in the literary realm, as products of the human imagination, provide a unique window into the folk-psychology of body and space.

Revisions of rump fat and body scoring indices for deer, elk, and moose

USGS Publications Warehouse

Cook, Rachel C.; Cook, John G.; Stephenson, Thomas R.; Myers, Woodrow L.; Mccorquodale, Scott M.; Vales, David J.; Irwin, Larry L.; Hall, P. Briggs; Spencer, Rocky D.; Murphie, Shannon L.; Schoenecker, Kathryn A.; Miller, Patrick J.

2010-01-01

Because they do not require sacrificing animals, body condition scores (BCS), thickness of rump fat (MAXFAT), and other similar predictors of body fat have advanced estimating nutritional condition of ungulates and their use has proliferated in North America in the last decade. However, initial testing of these predictors was too limited to assess their reliability among diverse habitats, ecotypes, subspecies, and populations across the continent. With data collected from mule deer (Odocoileus hemionus), elk (Cervus elaphus), and moose (Alces alces) during initial model development and data collected subsequently from free-ranging mule deer and elk herds across much of the western United States, we evaluated reliability across a broader range of conditions than were initially available. First, to more rigorously test reliability of the MAXFAT index, we evaluated its robustness across the 3 species, using an allometric scaling function to adjust for differences in animal size. We then evaluated MAXFAT, rump body condition score (rBCS), rLIVINDEX (an arithmetic combination of MAXFAT and rBCS), and our new allometrically scaled rump-fat thickness index using data from 815 free-ranging female Roosevelt and Rocky Mountain elk (C. e. roosevelti and C. e. nelsoni) from 19 populations encompassing 4 geographic regions and 250 free-ranging female mule deer from 7 populations and 2 regions. We tested for effects of subspecies, geographic region, and captive versus free-ranging existence. Rump-fat thickness, when scaled allometrically with body mass, was related to ingesta-free body fat over a 38–522-kg range of body mass (r2 = 0.87; P < 0.001), indicating the technique is remarkably robust among at least the 3 cervid species of our analysis. However, we found an underscoring bias with the rBCS for elk that had >12% body fat. This bias translated into a difference between subspecies, because Rocky Mountain elk tended to be fatter than Roosevelt elk in our sample. Effects of observer error with the rBCS also existed for mule deer with moderate to high levels of body fat, and deer body size significantly affected accuracy of the MAXFAT predictor. Our analyses confirm robustness of the rump-fat index for these 3 species but highlight the potential for bias due to differences in body size and to observer error with BCS scoring. We present alternative LIVINDEX equations where potential bias from rBCS and bias due to body size are eliminated or reduced. These modifications improve the accuracy of estimating body fat for projects intended to monitor nutritional status of herds or to evaluate nutrition's influence on population demographics.

Body shape convergence driven by small size optimum in marine angelfishes.

PubMed

Frédérich, Bruno; Santini, Francesco; Konow, Nicolai; Schnitzler, Joseph; Lecchini, David; Alfaro, Michael E

2017-06-01

Convergent evolution of small body size occurs across many vertebrate clades and may reflect an evolutionary response to shared selective pressures. However it remains unclear if other aspects of phenotype undergo convergent evolution in miniaturized lineages. Here we present a comparative analysis of body size and shape evolution in marine angelfishes (Pomacanthidae), a reef fish family characterized by repeated transitions to small body size. We ask if lineages that evolve small sizes show convergent evolution in body shape. Our results reveal that angelfish lineages evolved three different stable size optima with one corresponding to the group of pygmy angelfishes ( Centropyge ). Then, we test if the observed shifts in body size are associated with changes to new adaptive peaks in shape. Our data suggest that independent evolution to small size optima have induced repeated convergence upon deeper body and steeper head profile in Centropyge These traits may favour manoeuvrability and visual awareness in these cryptic species living among corals, illustrating that functional demands on small size may be related to habitat specialization and predator avoidance. The absence of shape convergence in large marine angelfishes also suggests that more severe requirements exist for small than for large size optima. © 2017 The Author(s).

Widespread rapid reductions in body size of adult salamanders in response to climate change.

PubMed

Caruso, Nicholas M; Sears, Michael W; Adams, Dean C; Lips, Karen R

2014-06-01

Reduction in body size is a major response to climate change, yet evidence in globally imperiled amphibians is lacking. Shifts in average population body size could indicate either plasticity in the growth response to changing climates through changes in allocation and energetics, or through selection for decreased size where energy is limiting. We compared historic and contemporary size measurements in 15 Plethodon species from 102 populations (9450 individuals) and found that six species exhibited significant reductions in body size over 55 years. Biophysical models, accounting for actual changes in moisture and air temperature over that period, showed a 7.1-7.9% increase in metabolic expenditure at three latitudes but showed no change in annual duration of activity. Reduced size was greatest at southern latitudes in regions experiencing the greatest drying and warming. Our results are consistent with a plastic response of body size to climate change through reductions in body size as mediated through increased metabolism. These rapid reductions in body size over the past few decades have significance for the susceptibility of amphibians to environmental change, and relevance for whether adaptation can keep pace with climate change in the future. © 2014 John Wiley & Sons Ltd.

The evolution of helicopters

NASA Astrophysics Data System (ADS)

Chen, R.; Wen, C. Y.; Lorente, S.; Bejan, A.

2016-07-01

Here, we show that during their half-century history, helicopters have been evolving into geometrically similar architectures with surprisingly sharp correlations between dimensions, performance, and body size. For example, proportionalities emerge between body size, engine size, and the fuel load. Furthermore, the engine efficiency increases with the engine size, and the propeller radius is roughly the same as the length scale of the whole body. These trends are in accord with the constructal law, which accounts for the engine efficiency trend and the proportionality between "motor" size and body size in animals and vehicles. These body-size effects are qualitatively the same as those uncovered earlier for the evolution of aircraft. The present study adds to this theoretical body of research the evolutionary design of all technologies [A. Bejan, The Physics of Life: The Evolution of Everything (St. Martin's Press, New York, 2016)].

Oesophageal foreign bodies in dogs: factors affecting success of endoscopic retrieval.

PubMed

Juvet, Florence; Pinilla, Manuel; Shiel, Robert E; Mooney, Carmel T

2010-03-01

Oesophageal foreign bodies are common in dogs. Endoscopic removal is a viable treatment option but few studies have assessed the clinical and radiographic features that would be useful in decision-making and prognosis.Dogs (n = 44) with oesophageal foreign bodies presented to the University Veterinary Hospital were assessed. Terriers and West Highland White Terriers were significantly overrepresented (p < 0.0001) and in those breeds the foreign body was significantly (p < 0.0001) more likely to be located caudal to the heart base. The majority (88.6%) of foreign bodies were bones or bone fragments.Group 1 (n = 30) included animals where endoscopic removal was successful and Group 2 (n = 14) animals where it was unsuccessful or not attempted because of evidence of oesophageal rupture. There was no statistically significant difference in age, sex, body weight, type, location and size of foreign body, recovery rate, short-term complications and long-term outcome between the two groups. Duration of signs prior to presentation and time to spontaneous oral feeding were significantly longer (p < 0.01 in each case) in Group 2 (five days and 120 hours, respectively) compared to Group 1 (2 days and 24 hours, respectively). Mortality was 11.1%. Long-term follow-up of 29 dogs suggested oesophageal stricture formation manageable by feeding alone in seven (24.1%) cases.Terriers appear predisposed to oesophageal foreign bodies. Success of endoscopic removal is adversely affected by duration of signs prior to presentation. Surgical removal negatively influences time to recovery. Stricture formation appears to be a relatively common complication and alternate measures for its prevention should be sought.

Oesophageal foreign bodies in dogs: factors affecting success of endoscopic retrieval

PubMed Central

2010-01-01

Oesophageal foreign bodies are common in dogs. Endoscopic removal is a viable treatment option but few studies have assessed the clinical and radiographic features that would be useful in decision-making and prognosis. Dogs (n = 44) with oesophageal foreign bodies presented to the University Veterinary Hospital were assessed. Terriers and West Highland White Terriers were significantly overrepresented (p < 0.0001) and in those breeds the foreign body was significantly (p < 0.0001) more likely to be located caudal to the heart base. The majority (88.6%) of foreign bodies were bones or bone fragments. Group 1 (n = 30) included animals where endoscopic removal was successful and Group 2 (n = 14) animals where it was unsuccessful or not attempted because of evidence of oesophageal rupture. There was no statistically significant difference in age, sex, body weight, type, location and size of foreign body, recovery rate, short-term complications and long-term outcome between the two groups. Duration of signs prior to presentation and time to spontaneous oral feeding were significantly longer (p < 0.01 in each case) in Group 2 (five days and 120 hours, respectively) compared to Group 1 (2 days and 24 hours, respectively). Mortality was 11.1%. Long-term follow-up of 29 dogs suggested oesophageal stricture formation manageable by feeding alone in seven (24.1%) cases. Terriers appear predisposed to oesophageal foreign bodies. Success of endoscopic removal is adversely affected by duration of signs prior to presentation. Surgical removal negatively influences time to recovery. Stricture formation appears to be a relatively common complication and alternate measures for its prevention should be sought. PMID:21851744

Assessment of liver size by ultrasonography.

PubMed

Patzak, Monika; Porzner, Marc; Oeztuerk, Suemeyra; Mason, Richard Andrew; Wilhelm, Manfred; Graeter, Tilmann; Kratzer, Wolfgang; Haenle, Mark Martin; Akinli, Atilla Serif

2014-09-01

To determine liver span sonographically in a randomly selected population sample and identify factors that affect liver size. A total of 1,789 subjects (963 females, 826 males; mean age 41.8 ± 12.8 years) underwent sonographic examination of the liver in the midclavicular line to determine liver span. Subjects underwent physical examination and blood tests and completed a standardized interview questionnaire. The average liver span in the midclavicular line for the overall collective was 15.0 ± 1.5 cm; the average for females was 14.9 ± 1.6 cm and 15.1 ± 1.5 cm for males. Liver span exceeded 16 cm in 24.3% of subjects. Results of the multivariate analysis showed that, of the factors potentially influencing liver span, gender, age, body mass index, body height, fatty liver (p < 0.0001), waist-to-hip ratio (p = 0.015), and metabolic syndrome (p = 0.032) are significant. By contrast, diabetes mellitus, alcohol consumption, tobacco consumption, physical activity, and laboratory findings showed no influence. Sonographic measurement of liver span in the midclavicular line is a simple method for routine clinical use. Gender, age, body mass index, waist-to-hip ratio, body height, hepatic steatosis, and metabolic syndrome are factors associated with liver span. © 2014 Wiley Periodicals, Inc.

From inflation to flotation: contribution of the swimbladder to whole-body density and swimming depth during development of the zebrafish (Danio rerio).

PubMed

Lindsey, Benjamin W; Smith, Frank M; Croll, Roger P

2010-03-01

Teleost fishes have body tissues that are denser than water, causing them to sink. Many teleosts therefore possess a gas-filled swimbladder that provides lift, allowing fish to attain neutral buoyancy. The importance of the swimbladder as a buoyancy aid during changing body sizes over ontogeny and its role in determining the swimming depth of fish remain unclear. In this study, we have used the zebrafish (Danio rerio) to investigate changes in the size and shape of the swimbladder during development and examine whether these changes affect the hydrostatic contribution of the swimbladder during swimming. Our results showed that swim-up behavior is critical for larvae to first inflate their swimbladder, decrease body density, and attain neutral buoyancy. Following inflation, we found a strong linear correlation between fish volume and swimbladder volume over ontogeny. This trend was supported by measures of the density of zebrafish, which was conserved within a narrow range between 1.00 +/- 0.001 and 0.996 +/- 0.001 g/cm(3) despite an increase in the swimming depth of zebrafish, which occurred upon transition to a double-chambered organ. Finally, we demonstrated that the contribution of the swimbladder keeps the fish within 1.7% of neutral buoyancy throughout larval development.

Personality differentially affects individual mate choice decisions in female and male Western mosquitofish (Gambusia affinis).

PubMed

Chen, Bo-Jian; Liu, Kai; Zhou, Lin-Jun; Gomes-Silva, Guilherme; Sommer-Trembo, Carolin; Plath, Martin

2018-01-01

Consistent individual differences in behavioral tendencies (animal personality) can affect individual mate choice decisions. We asked whether personality traits affect male and female mate choice decisions similarly and whether potential personality effects are consistent across different mate choice situations. Using western mosquitofish (Gambusia affinis) as our study organism, we characterized focal individuals (males and females) twice for boldness, activity, and sociability/shoaling and found high and significant behavioral repeatability. Additionally, each focal individual was tested in two different dichotomous mate choice tests in which it could choose between computer-animated stimulus fish of the opposite sex that differed in body size and activity levels, respectively. Personality had different effects on female and male mate choice: females that were larger than average showed stronger preferences for large-bodied males with increasing levels of boldness/activity (i.e., towards more proactive personality types). Males that were larger than average and had higher shoaling tendencies showed stronger preferences for actively swimming females. Size-dependent effects of personality on the strength of preferences for distinct phenotypes of potential mating partners may reflect effects of age/experience (especially in females) and social dominance (especially in males). Previous studies found evidence for assortative mate choice based on personality types or hypothesized the existence of behavioral syndromes of individuals' choosiness across mate choice criteria, possibly including other personality traits. Our present study exemplifies that far more complex patterns of personality-dependent mate choice can emerge in natural systems.

Scale-Dependent Habitat Selection and Size-Based Dominance in Adult Male American Alligators

PubMed Central

Strickland, Bradley A.; Vilella, Francisco J.; Belant, Jerrold L.

2016-01-01

Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance and space use can provide great insight into their functional role in the ecosystem. PMID:27588947

Scale-dependent habitat selection and size-based dominance in adult male American alligators

USGS Publications Warehouse

Strickland, Bradley A.; Vilella, Francisco; Belant, Jerrold L.

2016-01-01

Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance and space use can provide great insight into their functional role in the ecosystem.

A free flight investigation of transonic sting interference

NASA Technical Reports Server (NTRS)

Jaffe, P.

1975-01-01

Transonic sting interference has been studied in a supersonic wind tunnel to obtain free flight and sting support data on identical models. The two principal configurations, representing fuselage bodies, were cigar shaped with tail fins. The others were a sharp 10-deg cone, a sphere, and a blunt entry body. Comparative data indicated that the sting had an appreciable effect on drag for the fuselage-like configurations; drag rise occurred 0.02 Mach number earlier in free flight, and drag level was 15% greater. The spheres and the blunt bodies were insensitive to the presence of stings regardless of their size. The 10-deg cones were in between, experiencing no drag difference with a minimum diameter sting, but a moderate difference with the largest diameter sting tested. All data tend to confirm the notion that for the more slender bodies the sting not only affects flow but the forebody flow as well.

On the origin of the moon, with emphasis on bulk composition

NASA Technical Reports Server (NTRS)

Kaula, W. M.

1977-01-01

A new analysis of altimetric, gravimetric, and seismological results, together with petrological and thermal history constraints, obtains an estimated Al2O3 content of 5.0%, 2.1 times chondritic. Hence the moon definitely has a refractory lithophile excess as well as an iron deficiency. In addition, the lunar surface is characterized by refractory siderophile depletions. The combination of these properties appears to require a previous stage of differentiation in a planetary body or bodies. Siderophile and chalcolphile depletions and dispersions in eucrites suggest that these bodies are not necessarily large. Possible mechanisms of lunar formation include impacting of a very large body into the earth; tidal disruption of sizeable differentiated planetesimals by the earth; and selective capture of differentiated planetesimal material by small moonlets. Each mechanism has its difficulties; the major unknown affecting all of them is the size distribution of planetesimals.

Climate warming and Bergmann's rule through time: is there any evidence?

PubMed Central

Teplitsky, Celine; Millien, Virginie

2014-01-01

Climate change is expected to induce many ecological and evolutionary changes. Among these is the hypothesis that climate warming will cause a reduction in body size. This hypothesis stems from Bergmann's rule, a trend whereby species exhibit a smaller body size in warmer climates, and larger body size under colder conditions in endotherms. The mechanisms behind this rule are still debated, and it is not clear whether Bergmann's rule can be extended to predict the effects of climate change through time. We reviewed the primary literature for evidence (i) of a decrease in body size in response to climate warming, (ii) that changing body size is an adaptive response and (iii) that these responses are evolutionary or plastic. We found weak evidence for changes in body size through time as predicted by Bergmann's rule. Only three studies investigated the adaptive nature of these size decreases. Of these, none reported evidence of selection for smaller size or of a genetic basis for the size change, suggesting that size decreases could be due to nonadaptive plasticity in response to changing environmental conditions. More studies are needed before firm conclusions can be drawn about the underlying causes of these changes in body size in response to a warming climate. PMID:24454554

Body Size Adaptations to Altitudinal Climatic Variation in Neotropical Grasshoppers of the Genus Sphenarium (Orthoptera: Pyrgomorphidae)

PubMed Central

2015-01-01

Altitudinal clines in body size can result from the effects of natural and sexual selection on growth rates and developing times in seasonal environments. Short growing and reproductive seasons constrain the body size that adults can attain and their reproductive success. Little is known about the effects of altitudinal climatic variation on the diversification of Neotropical insects. In central Mexico, in addition to altitude, highly heterogeneous topography generates diverse climates that can occur even at the same latitude. Altitudinal variation and heterogeneous topography open an opportunity to test the relative impact of climatic variation on body size adaptations. In this study, we investigated the relationship between altitudinal climatic variation and body size, and the divergence rates of sexual size dimorphism (SSD) in Neotropical grasshoppers of the genus Sphenarium using a phylogenetic comparative approach. In order to distinguish the relative impact of natural and sexual selection on the diversification of the group, we also tracked the altitudinal distribution of the species and trends of both body size and SSD on the phylogeny of Sphenarium. The correlative evidence suggests no relationship between altitude and body size. However, larger species were associated with places having a warmer winter season in which the temporal window for development and reproduction can be longer. Nonetheless, the largest species were also associated with highly seasonal environments. Moreover, large body size and high levels of SSD have evolved independently several times throughout the history of the group and male body size has experienced a greater evolutionary divergence than females. These lines of evidence suggest that natural selection, associated with seasonality and sexual selection, on maturation time and body size could have enhanced the diversification of this insect group. PMID:26684616

Body size-trophic position relationships among fishes of the lower Mekong basin.

PubMed

Ou, Chouly; Montaña, Carmen G; Winemiller, Kirk O

2017-01-01

Body size is frequently claimed to be a major determinant of animal trophic interactions, yet few studies have explored relationships between body size and trophic interactions in rivers, especially within the tropics. We examined relationships between body size and trophic position (TP) within fish assemblages in four lowland rivers of the Lower Mekong Basin in Cambodia. Stable isotope analysis (based on δ 15 N) was used to estimate TP of common fish species in each river, and species were classified according to occupation of benthic versus pelagic habitats and major feeding guilds. Regression analysis yielded strong correlations between body size and TP among fishes from the Sesan and Sreprok rivers, but not those from the Mekong and Sekong rivers. The Mekong fish assemblage had higher average TP compared with those of other rivers. The relationship between body size and TP was positive and significantly correlated for piscivores and omnivores, but not for detritivores and insectivores. The body size-TP relationship did not differ between pelagic and benthic fishes. Body size significantly predicted TP within the orders Siluriformes and Perciformes, but not for Cypriniformes, the most species-rich and ecologically diverse order in the Lower Mekong River. We conclude that for species-rich, tropical fish assemblages with many detritivores and invertivores, body size would not be an appropriate surrogate for TP in food web models and other ecological applications.

Predictive equations for the estimation of body size in seals and sea lions (Carnivora: Pinnipedia)

PubMed Central

Churchill, Morgan; Clementz, Mark T; Kohno, Naoki

2014-01-01

Body size plays an important role in pinniped ecology and life history. However, body size data is often absent for historical, archaeological, and fossil specimens. To estimate the body size of pinnipeds (seals, sea lions, and walruses) for today and the past, we used 14 commonly preserved cranial measurements to develop sets of single variable and multivariate predictive equations for pinniped body mass and total length. Principal components analysis (PCA) was used to test whether separate family specific regressions were more appropriate than single predictive equations for Pinnipedia. The influence of phylogeny was tested with phylogenetic independent contrasts (PIC). The accuracy of these regressions was then assessed using a combination of coefficient of determination, percent prediction error, and standard error of estimation. Three different methods of multivariate analysis were examined: bidirectional stepwise model selection using Akaike information criteria; all-subsets model selection using Bayesian information criteria (BIC); and partial least squares regression. The PCA showed clear discrimination between Otariidae (fur seals and sea lions) and Phocidae (earless seals) for the 14 measurements, indicating the need for family-specific regression equations. The PIC analysis found that phylogeny had a minor influence on relationship between morphological variables and body size. The regressions for total length were more accurate than those for body mass, and equations specific to Otariidae were more accurate than those for Phocidae. Of the three multivariate methods, the all-subsets approach required the fewest number of variables to estimate body size accurately. We then used the single variable predictive equations and the all-subsets approach to estimate the body size of two recently extinct pinniped taxa, the Caribbean monk seal (Monachus tropicalis) and the Japanese sea lion (Zalophus japonicus). Body size estimates using single variable regressions generally under or over-estimated body size; however, the all-subset regression produced body size estimates that were close to historically recorded body length for these two species. This indicates that the all-subset regression equations developed in this study can estimate body size accurately. PMID:24916814

Larger Mammalian Body Size Leads to Lower Retroviral Activity

PubMed Central

Katzourakis, Aris; Magiorkinis, Gkikas; Lim, Aaron G.; Gupta, Sunetra; Belshaw, Robert; Gifford, Robert

2014-01-01

Retroviruses have been infecting mammals for at least 100 million years, leaving descendants in host genomes known as endogenous retroviruses (ERVs). The abundance of ERVs is partly determined by their mode of replication, but it has also been suggested that host life history traits could enhance or suppress their activity. We show that larger bodied species have lower levels of ERV activity by reconstructing the rate of ERV integration across 38 mammalian species. Body size explains 37% of the variance in ERV integration rate over the last 10 million years, controlling for the effect of confounding due to other life history traits. Furthermore, 68% of the variance in the mean age of ERVs per genome can also be explained by body size. These results indicate that body size limits the number of recently replicating ERVs due to their detrimental effects on their host. To comprehend the possible mechanistic links between body size and ERV integration we built a mathematical model, which shows that ERV abundance is favored by lower body size and higher horizontal transmission rates. We argue that because retroviral integration is tumorigenic, the negative correlation between body size and ERV numbers results from the necessity to reduce the risk of cancer, under the assumption that this risk scales positively with body size. Our model also fits the empirical observation that the lifetime risk of cancer is relatively invariant among mammals regardless of their body size, known as Peto's paradox, and indicates that larger bodied mammals may have evolved mechanisms to limit ERV activity. PMID:25033295

The Relationship of Body Size and Adiposity to Source of Self-Esteem in College Women

ERIC Educational Resources Information Center

Moncur, Breckann; Bailey, Bruce W.; Lockhart, Barbara D.; LeCheminant, James D.; Perkins, Annette E.

2013-01-01

Background: Studies looking at self-esteem and body size or adiposity generally demonstrate a negative relationship. However, the relationship between the source of self-esteem and body size has not been examined in college women. Purpose: The purpose of this study was to evaluate the relationship of body size and adiposity to source of…

Body size satisfaction and physical activity levels among men and women.

PubMed

Kruger, Judy; Lee, Chong-Do; Ainsworth, Barbara E; Macera, Caroline A

2008-08-01

Body size satisfaction may be an important factor associated with physical activity. We analyzed data from the 2002 National Physical Activity and Weight Loss Survey (NPAWLS), a population-based cross-sectional telephone survey of US adults. Multiple logistic regression models were used to examine the association of body size satisfaction on being regularly active. Participants were aged > or =18 years with complete data on weight, race/ethnicity, physical activity level, and body size satisfaction (n = 10,021). More than half of men (55.8%) and women (53.3%) who reported being very satisfied with the body size were regularly active. After adjustment for covariates, participants who reported being somewhat or not satisfied with their body size had a 13 and 44% lower odds of being regularly active, respectively, compared with those very satisfied with their body size. When stratified by race/ethnicity, this association remained in whites (P for trend <0.001), but became weaker and nonsignificant in blacks, Hispanics, or other racial/ethnic groups. Irrespective of actual weight, those who were satisfied with their body size were more likely to engage in regular physical activity than those less satisfied. Further research is needed to explore predictors of physical activity to reduce health disparities.

Size matters for lice on birds: Coevolutionary allometry of host and parasite body size.

PubMed

Harnos, Andrea; Lang, Zsolt; Petrás, Dóra; Bush, Sarah E; Szabó, Krisztián; Rózsa, Lajos

2017-02-01

Body size is one of the most fundamental characteristics of all organisms. It influences physiology, morphology, behavior, and even interspecific interactions such as those between parasites and their hosts. Host body size influences the magnitude and variability of parasite size according to Harrison's rule (HR: positive relationship between host and parasite body sizes) and Poulin's Increasing Variance Hypothesis (PIVH: positive relationship between host body size and the variability of parasite body size). We analyzed parasite-host body size allometry for 581 species of avian lice (∼15% of known diversity) and their hosts. We applied phylogenetic generalized least squares (PGLS) methods to account for phylogenetic nonindependence controlling for host and parasite phylogenies separately and variance heterogeneity. We tested HR and PIVH for the major families of avian lice (Ricinidae, Menoponidae, Philopteridae), and for distinct ecological guilds within Philopteridae. Our data indicate that most families and guilds of avian lice follow both HR and PIVH; however, ricinids did not follow PIVH and the "body lice" guild of philopterid lice did not follow HR or PIVH. We discuss mathematical and ecological factors that may be responsible for these patterns, and we discuss the potential pervasiveness of these relationships among all parasites on Earth. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Dissociation of somatic growth from segmentation drives gigantism in snakes.

PubMed

Head, Jason J; David Polly, P

2007-06-22

Body size is significantly correlated with number of vertebrae (pleomerism) in multiple vertebrate lineages, indicating that change in number of body segments produced during somitogenesis is an important factor in evolutionary change in body size, but the role of segmentation in the evolution of extreme sizes, including gigantism, has not been examined. We explored the relationship between body size and vertebral count in basal snakes that exhibit gigantism. Boids, pythonids and the typhlopid genera, Typhlops and Rhinotyphlops, possess a positive relationship between body size and vertebral count, confirming the importance of pleomerism; however, giant taxa possessed fewer than expected vertebrae, indicating that a separate process underlies the evolution of gigantism in snakes. The lack of correlation between body size and vertebral number in giant taxa demonstrates dissociation of segment production in early development from somatic growth during maturation, indicating that gigantism is achieved by modifying development at a different stage from that normally selected for changes in body size.

The influence of body size on the pharmacodynamic and pharmacokinetic response to clopidogrel and prasugrel: a retrospective analysis of the FEATHER study.

PubMed

Jakubowski, Joseph A; Angiolillo, Dominick J; Zhou, Chunmei; Small, David S; Moser, Brian A; Ten Berg, Jurrien M; Brown, Patricia B; James, Stefan; Winters, Kenneth J; Erlinge, David

2014-09-01

Patients treated with clopidogrel who have higher body size exhibit greater platelet reactivity than patients with lower body size. In a retrospective analysis of the FEATHER trial, we examined the relationship between platelet response to thienopyridines clopidogrel 75 mg (Clop-75), prasugrel 5mg (Pras-5), and prasugrel 10mg (Pras-10) using 3 body size indices: body weight (BW), body mass index (BMI), and body surface area (BSA). Relationships were assessed as continuous variables and as 4 incremental body size groups. Aspirin-treated patients with stable coronary artery disease (N=72) and a BW range of 45-134 kg received Clop-75, Pras-5, and Pras-10 in a 3-period, blinded, cross-over study. Platelet assays included maximum platelet aggregation (MPA) to 20μM ADP by light transmission aggregometry, VerifyNow-P2Y12 reaction units (PRU), and vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation platelet reactivity index (PRI). Exposure to active metabolites (AMs) was also assessed. Body size was a determinant of AM exposure and residual platelet reactivity regardless of type and dose of thienopyridine. BW and BSA demonstrated marginally stronger correlations with platelet reactivity; VASP-PRI demonstrated a stronger correlation with the body size than the other tests. Correlation coefficients ranged from a high of 0.64 (BW vs. PRI on Pras-5) to a low of 0.34 (BMI vs. MPA on Pras-10), but all were statistically significant (p<0.01). Using a comprehensive selection of body size indices, AM exposures, platelet function tests, and thienopyridine doses, we demonstrated a consistent inverse relationship between body size and response to clopidogrel and prasugrel. Copyright © 2014 Elsevier Ltd. All rights reserved.

Clinical Muscle Testing Compared with Whole-Body Magnetic Resonance Imaging in Facio-scapulo-humeral Muscular Dystrophy.

PubMed

Regula, J U; Jestaedt, L; Jende, F; Bartsch, A; Meinck, H-M; Weber, M-A

2016-12-01

The objective of this study was to evaluate the clinical usefulness of whole-body magnetic resonance imaging (MRI) in facio-scapulo-humeral muscular dystrophy (FSHD). In 20 patients with genetically proven FSHD1, we prospectively assessed muscular involvement and correlated the results of semi-quantitative manual muscle testing and other parameters such as disease duration, creatine kinase (CK) levels and repeat length of the D4Z4 locus with whole-body MRI. Clinical muscle testing revealed the trapezius, pectoralis and infraspinatus as the most severely affected muscles in the shoulder, and the knee flexors and gluteus medius in the hip girdle. MRI revealed the trapezius and serratus anterior muscles in the shoulder, and the hamstrings and adductor muscles in the hip girdle, as the most severely affected muscle groups. Overall, degrees of fatty degeneration on MRI scans correlated significantly with clinical weakness. Moreover, we could detect clear affection of the trunk muscles. Corresponding to earlier reports, asymmetric involvement was frequent in both clinical examination and MRI scoring. Moreover, MRI revealed inhomogeneous muscle degeneration in a considerable proportion of both, muscles and patients. Both clinical and MRI scores significantly correlated to disease duration, but not to fragment size or CK levels. Fatty degeneration in whole-body MRI correlates well to clinical muscle testing of the extremities but gives more information on deeper or trunk muscles. It shows structural changes in muscular disorders and may become an excellent tool for assessment of muscle involvement and follow-up studies.

Island colonisation and the evolutionary rates of body size in insular neonate snakes

PubMed Central

Aubret, F

2015-01-01

Island colonisation by animal populations is often associated with dramatic shifts in body size. However, little is known about the rates at which these evolutionary shifts occur, under what precise selective pressures and the putative role played by adaptive plasticity on driving such changes. Isolation time played a significant role in the evolution of body size in island Tiger snake populations, where adaptive phenotypic plasticity followed by genetic assimilation fine-tuned neonate body and head size (hence swallowing performance) to prey size. Here I show that in long isolated islands (>6000 years old) and mainland populations, neonate body mass and snout-vent length are tightly correlated with the average prey body mass available at each site. Regression line equations were used to calculate body size values to match prey size in four recently isolated populations of Tiger snakes. Rates of evolution in body mass and snout-vent length, calculated for seven island snake populations, were significantly correlated with isolation time. Finally, rates of evolution in body mass per generation were significantly correlated with levels of plasticity in head growth rates. This study shows that body size evolution occurs at a faster pace in recently isolated populations and suggests that the level of adaptive plasticity for swallowing abilities may correlate with rates of body mass evolution. I hypothesise that, in the early stages of colonisation, adaptive plasticity and directional selection may combine and generate accelerated evolution towards an ‘optimal' phenotype. PMID:25074570

Temperature-Dependent Growth and Fission Rate Plasticity Drive Seasonal and Geographic Changes in Body Size in a Clonal Sea Anemone.

PubMed

Ryan, Will H

2018-02-01

The temperature-size rule is a commonly observed pattern where adult body size is negatively correlated with developmental temperature. In part, this may occur as a consequence of allometric scaling, where changes in the ratio of surface area to mass limit oxygen diffusion as body size increases. As oxygen demand increases with temperature, a smaller body should be favored as temperature increases. For clonal animals, small changes in growth and/or fission rate can rapidly alter the average body size of clonal descendants. Here I test the hypothesis that the clonal sea anemone Diadumene lineata is able to track an optimal body size through seasonal temperature changes using fission rate plasticity. Individuals from three regions (Florida, Georgia, and Massachusetts) across the species' latitudinal range were grown in a year-long reciprocal common garden experiment mimicking seasonal temperature changes at three sites. Average body size was found to be smaller and fission rates higher in warmer conditions, consistent with the temperature-size rule pattern. However, seasonal size and fission patterns reflect a complex interaction between region-specific thermal reaction norms and the local temperature regime. These details provide insight into both the range of conditions required for oxygen limitation to contribute to a negative correlation between body size and temperature and the role that fission rate plasticity can play in tracking a rapidly changing optimal phenotype.

Sex allocation and secondary sex ratio in Cuban boa ( Chilabothrus angulifer): mother's body size affects the ratio between sons and daughters

NASA Astrophysics Data System (ADS)

Frynta, Daniel; Vejvodová, Tereza; Šimková, Olga

2016-06-01

Secondary sex ratios of animals with genetically determined sex may considerably deviate from equality. These deviations may be attributed to several proximate and ultimate factors. Sex ratio theory explains some of them as strategic decisions of mothers improving their fitness by selective investment in sons or daughters, e.g. local resource competition hypothesis (LRC) suggests that philopatric females tend to produce litters with male-biased sex ratios to avoid future competition with their daughters. Until now, only little attention has been paid to examine predictions of sex ratio theory in snakes possessing genetic sex determination and exhibiting large variance in allocation of maternal investment. Cuban boa is an endemic viviparous snake producing large-bodied newborns (˜200 g). Extremely high maternal investment in each offspring increases importance of sex allocation. In a captive colony, we collected breeding records of 42 mothers, 62 litters and 306 newborns and examined secondary sex ratios (SR) and sexual size dimorphism (SSD) of newborns. None of the examined morphometric traits of neonates appeared sexually dimorphic. The sex ratio was slightly male biased (174 males versus 132 females) and litter sex ratio significantly decreased with female snout-vent length. We interpret this relationship as an additional support for LRC as competition between mothers and daughters increases with similarity of body sizes between competing snakes.

Sex allocation and secondary sex ratio in Cuban boa (Chilabothrus angulifer): mother's body size affects the ratio between sons and daughters.

PubMed

Frynta, Daniel; Vejvodová, Tereza; Šimková, Olga

2016-06-01

Secondary sex ratios of animals with genetically determined sex may considerably deviate from equality. These deviations may be attributed to several proximate and ultimate factors. Sex ratio theory explains some of them as strategic decisions of mothers improving their fitness by selective investment in sons or daughters, e.g. local resource competition hypothesis (LRC) suggests that philopatric females tend to produce litters with male-biased sex ratios to avoid future competition with their daughters. Until now, only little attention has been paid to examine predictions of sex ratio theory in snakes possessing genetic sex determination and exhibiting large variance in allocation of maternal investment. Cuban boa is an endemic viviparous snake producing large-bodied newborns (∼200 g). Extremely high maternal investment in each offspring increases importance of sex allocation. In a captive colony, we collected breeding records of 42 mothers, 62 litters and 306 newborns and examined secondary sex ratios (SR) and sexual size dimorphism (SSD) of newborns. None of the examined morphometric traits of neonates appeared sexually dimorphic. The sex ratio was slightly male biased (174 males versus 132 females) and litter sex ratio significantly decreased with female snout-vent length. We interpret this relationship as an additional support for LRC as competition between mothers and daughters increases with similarity of body sizes between competing snakes.

Body shape and size depictions of African American women in JET magazine, 1953-2006.

PubMed

Dawson-Andoh, Nana A; Gray, James J; Soto, José A; Parker, Scott

2011-01-01

Depictions of Caucasian women in the mainstream media have become increasingly thinner in size and straighter in shape. These changes may be inconsistent with the growing influence of African American beauty ideals, which research has established as more accepting of larger body sizes and more curvaceous body types than Caucasians. The present study looked at trends in the portrayal of African American women featured in JET magazine from 1953 to 2006. Beauty of the Week (BOW) images were collected and analyzed to examine body size (estimated by independent judges) and body shape (estimated by waist-to-hip ratio). We expected body sizes to increase and body shapes to become more curvaceous. Results revealed a rise in models' body size consistent with expectations, but an increase in waist-to-hip ratio, contrary to prediction. Our findings suggest that the African American feminine beauty ideal reflects both consistencies with and departures from mainstream cultural ideals. Copyright © 2010 Elsevier Ltd. All rights reserved.

Explaining body size beliefs in anorexia.

PubMed

Gadsby, Stephen

2017-11-01

Cognitive neuropsychiatry has had much success in providing theoretical models for the causal origins of many delusional beliefs. Recently, it has been suggested that some anorexia nervosa patients' beliefs about their own body size should be considered delusions. As such, it seems high time the methods of cognitive neuropsychiatry were turned to modelling the false body size beliefs of anorexics. In this paper, I adopt an empiricist approach to modelling the causal origins of false body size beliefs in anorexia. Within the background of cognitive neuropsychiatry, empiricist models claim that abnormal beliefs are grounded by abnormal experiences bearing similar content. I discuss the kinds of abnormal experiences of body size anorexics suffer from which could ground their false beliefs about body size. These oversized experiences come in three varieties: false self-other body comparisons, spontaneous mental imagery of a fat body and distorted perception of affordances. Further theoretical and empirical research into the oversized experiences which anorexics suffer from presents a promising avenue for understanding and treating the disorder.

Physical capital and the embodied nature of income inequality: gender differences in the effect of body size on workers' incomes in Canada.

PubMed

Perks, Thomas

2012-02-01

This study assesses the effects of body size--measured using the body mass index--on the income attainment of female and male workers in Canada. Using data from a national representative sample of Canadians, multivariate analyses show that, for female workers, the body size-income relationship is negative. However, for male workers, the body size-income relationship is positive and nonlinear. Using Bourdieu's conceptualization of physical capital, and Shilling's extension of it, it is argued that these results are suggestive of the relative importance of body size to the production and continuation of gender income inequality in Canada.

Influence of Roost Site Selection on the Energetic Efficiency and Distribution of Starlings and Blackbirds: A Way of Controlling Blackbird Populations Near Airports.

DTIC Science & Technology

1981-05-01

differences present since males and females are sexually dimorphic with regard to body weight and MR is affected by the size of t the bird. Hart (1962...810). Birds were kept at ambient temperatures ranging from 5.0 to -10.0 C on natural photoperiods and were provided turkey pellets (Ralston Purina Co

Male Responses to Conspecific Advertisement Signals in the Field Cricket Gryllus rubens (Orthoptera: Gryllidae)

PubMed Central

Jang, Yikweon

2011-01-01

In many species males aggregate and produce long-range advertisement signals to attract conspecific females. The majority of the receivers of these signals are probably other males most of the time, and male responses to competitors' signals can structure the spatial and temporal organization of the breeding aggregation and affect male mating tactics. I quantified male responses to a conspecific advertisement stimulus repeatedly over three age classes in Gryllus rubens (Orthoptera: Gryllidae) in order to estimate the type and frequency of male responses to the broadcast stimulus and to determine the factors affecting them. Factors tested included body size, wing dimorphism, age, and intensity of the broadcast stimulus. Overall, males employed acoustic response more often than positive phonotactic response. As males aged, the frequency of positive phonotactic response decreased but that of the acoustic response increased. That is, males may use positive phonotaxis in the early stages of their adult lives, possibly to find suitable calling sites or parasitize calling males, and then later in life switch to acoustic responses in response to conspecific advertisement signals. Males with smaller body size more frequently exhibited acoustic responses. This study suggests that individual variation, more than any factors measured, is critical for age-dependent male responses to conspecific advertisement signals. PMID:21283758

Male responses to conspecific advertisement signals in the field cricket Gryllus rubens (Orthoptera: Gryllidae).

PubMed

Jang, Yikweon

2011-01-20

In many species males aggregate and produce long-range advertisement signals to attract conspecific females. The majority of the receivers of these signals are probably other males most of the time, and male responses to competitors' signals can structure the spatial and temporal organization of the breeding aggregation and affect male mating tactics. I quantified male responses to a conspecific advertisement stimulus repeatedly over three age classes in Gryllus rubens (Orthoptera: Gryllidae) in order to estimate the type and frequency of male responses to the broadcast stimulus and to determine the factors affecting them. Factors tested included body size, wing dimorphism, age, and intensity of the broadcast stimulus. Overall, males employed acoustic response more often than positive phonotactic response. As males aged, the frequency of positive phonotactic response decreased but that of the acoustic response increased. That is, males may use positive phonotaxis in the early stages of their adult lives, possibly to find suitable calling sites or parasitize calling males, and then later in life switch to acoustic responses in response to conspecific advertisement signals. Males with smaller body size more frequently exhibited acoustic responses. This study suggests that individual variation, more than any factors measured, is critical for age-dependent male responses to conspecific advertisement signals.

What is the psychological impact of self-weighing? A meta-analysis.

PubMed

Benn, Yael; Webb, Thomas L; Chang, Betty P I; Harkin, Benjamin

2016-06-01

Many people self-weigh and many interventions addressing weight-related problems such as obesity promote self-weighing. However, while self-weighing has been associated with weight loss, there is mixed evidence regarding the psychological impact of this behaviour. The present review aimed to quantify the relationship between self-weighing and: (i) affect (e.g., anxiety, depression); (ii) psychological functioning (e.g., self-esteem); (iii) body-related attitudes and (iv) disordered eating. A computerized search of scientific databases in September 2014 and subsequent ancestry and citation searches identified 29 independent tests of the relationship between self-weighing on psychological outcomes. Meta-analysis was used to quantify the size of the association across the tests. Results indicated that there was no association between self-weighing and affect, body-related attitudes or disordered eating. There was, however, a small-sized negative association between self-weighing and psychological functioning. The age of participants, obesity status, the extent of weight loss, duration of self-weighing and study design (RCT versus correlational) were found to influence at least some of the psychological outcomes of self-weighing. The findings suggest that, for the most part, self-weighing is not associated with adverse psychological outcomes. However, in some cases the association between self-weighing and psychological outcomes may be more negative than in others.

What is the psychological impact of self-weighing? A meta-analysis

PubMed Central

Benn, Yael; Webb, Thomas L.; Chang, Betty P. I.; Harkin, Benjamin

2016-01-01

ABSTRACT Many people self-weigh and many interventions addressing weight-related problems such as obesity promote self-weighing. However, while self-weighing has been associated with weight loss, there is mixed evidence regarding the psychological impact of this behaviour. The present review aimed to quantify the relationship between self-weighing and: (i) affect (e.g., anxiety, depression); (ii) psychological functioning (e.g., self-esteem); (iii) body-related attitudes and (iv) disordered eating. A computerized search of scientific databases in September 2014 and subsequent ancestry and citation searches identified 29 independent tests of the relationship between self-weighing on psychological outcomes. Meta-analysis was used to quantify the size of the association across the tests. Results indicated that there was no association between self-weighing and affect, body-related attitudes or disordered eating. There was, however, a small-sized negative association between self-weighing and psychological functioning. The age of participants, obesity status, the extent of weight loss, duration of self-weighing and study design (RCT versus correlational) were found to influence at least some of the psychological outcomes of self-weighing. The findings suggest that, for the most part, self-weighing is not associated with adverse psychological outcomes. However, in some cases the association between self-weighing and psychological outcomes may be more negative than in others. PMID:26742706

The Fat-Dachsous signaling pathway regulates growth of horns in Trypoxylus dichotomus, but does not affect horn allometry.

PubMed

Hust, James; Lavine, Mark D; Worthington, Amy M; Zinna, Robert; Gotoh, Hiroki; Niimi, T; Lavine, Laura

Males of the Asian rhinoceros beetle, Trypoxylus dichotomus, possess exaggerated head and thoracic horns that scale dramatically out of proportion to body size. While studies of insulin signaling suggest that this pathway regulates nutrition-dependent growth including exaggerated horns, what regulates disproportionate growth has yet to be identified. The Fat signaling pathway is a potential candidate for regulating disproportionate growth of sexually-selected traits, a hypothesis we advanced in a previous paper (Gotoh et al., 2015). To investigate the role of Fat signaling in the growth and scaling of the sexually dimorphic, condition-dependent traits of the in the Asian rhinoceros beetle T. dichotomus, we used RNA interference to knock down expression of fat and its co-receptor dachsous. Knockdown of fat, and to a lesser degree dachsous, caused shortening and widening of appendages, including the head and thoracic horns. However, scaling of horns to body size was not affected. Our results show that Fat signaling regulates horn growth in T. dichotomus as it does in appendage growth in other insects. However, we provide evidence that Fat signaling does not mediate the disproportionate, positive allometric growth of horns in T. dichotomus. Copyright © 2018 Elsevier Ltd. All rights reserved.

Body-part compatibility effects are modulated by the tendency for women to experience negative social comparative emotions and the body-type of the model.

PubMed

Pila, Eva; Jovanov, Kimberely; Welsh, Timothy N; Sabiston, Catherine M

2017-01-01

Although exposure to physique-salient media images of women's bodies has been consistently linked with negative psychological consequences, little is known about the cognitive processes that lead to these negative effects. The present study employed a novel adaptation of a computerized response time (RT) task to (i) assess implicit cognitive processing when exposed to the body of another individual, and (ii) examine individual differences in social comparative emotions that may influence the cognitive processing of human bodies. Adult females with low (n = 44) or high (n = 23) tendencies for comparative emotions completed a task in which they executed responses to coloured targets presented on the hands or feet of images of ultra-thin, average-size, and above average-size female models. Although the colour of the target is the only relevant target feature, it is typically found that the to-be-ignored location of the target on the body of the model influences RTs such that RTs are shorter when the target is on a body-part that is compatible with the responding limb (e.g., hand response when target was on hand) than on a body-part that is incompatible with the responding limb (e.g., hand response when target was on foot). Findings from the present study revealed that the magnitude of the body-part compatibility effect (i.e., the index of the cognitive processing of the model) was modulated by tendencies for affective body-related comparisons. Specifically, women who were prone to experiencing social comparative emotions demonstrated stronger and more consistent body-part compatibility effects across models. Therefore, women with higher social comparison tendencies have heightened processing of bodies at a neurocognitive level and may be at higher risk of the negative outcomes linked with physique-salient media exposure.

Body-part compatibility effects are modulated by the tendency for women to experience negative social comparative emotions and the body-type of the model

PubMed Central

Jovanov, Kimberely; Welsh, Timothy N.; Sabiston, Catherine M.

2017-01-01

Although exposure to physique-salient media images of women’s bodies has been consistently linked with negative psychological consequences, little is known about the cognitive processes that lead to these negative effects. The present study employed a novel adaptation of a computerized response time (RT) task to (i) assess implicit cognitive processing when exposed to the body of another individual, and (ii) examine individual differences in social comparative emotions that may influence the cognitive processing of human bodies. Adult females with low (n = 44) or high (n = 23) tendencies for comparative emotions completed a task in which they executed responses to coloured targets presented on the hands or feet of images of ultra-thin, average-size, and above average-size female models. Although the colour of the target is the only relevant target feature, it is typically found that the to-be-ignored location of the target on the body of the model influences RTs such that RTs are shorter when the target is on a body-part that is compatible with the responding limb (e.g., hand response when target was on hand) than on a body-part that is incompatible with the responding limb (e.g., hand response when target was on foot). Findings from the present study revealed that the magnitude of the body-part compatibility effect (i.e., the index of the cognitive processing of the model) was modulated by tendencies for affective body-related comparisons. Specifically, women who were prone to experiencing social comparative emotions demonstrated stronger and more consistent body-part compatibility effects across models. Therefore, women with higher social comparison tendencies have heightened processing of bodies at a neurocognitive level and may be at higher risk of the negative outcomes linked with physique-salient media exposure. PMID:28632746

Male songbird indicates body size with low-pitched advertising songs.

PubMed

Hall, Michelle L; Kingma, Sjouke A; Peters, Anne

2013-01-01

Body size is a key sexually selected trait in many animal species. If size imposes a physical limit on the production of loud low-frequency sounds, then low-pitched vocalisations could act as reliable signals of body size. However, the central prediction of this hypothesis--that the pitch of vocalisations decreases with size among competing individuals--has limited support in songbirds. One reason could be that only the lowest-frequency components of vocalisations are constrained, and this may go unnoticed when vocal ranges are large. Additionally, the constraint may only be apparent in contexts when individuals are indeed advertising their size. Here we explicitly consider signal diversity and performance limits to demonstrate that body size limits song frequency in an advertising context in a songbird. We show that in purple-crowned fairy-wrens, Malurus coronatus coronatus, larger males sing lower-pitched low-frequency advertising songs. The lower frequency bound of all advertising song types also has a significant negative relationship with body size. However, the average frequency of all their advertising songs is unrelated to body size. This comparison of different approaches to the analysis demonstrates how a negative relationship between body size and song frequency can be obscured by failing to consider signal design and the concept of performance limits. Since these considerations will be important in any complex communication system, our results imply that body size constraints on low-frequency vocalisations could be more widespread than is currently recognised.

Male Songbird Indicates Body Size with Low-Pitched Advertising Songs

PubMed Central

Hall, Michelle L.; Kingma, Sjouke A.; Peters, Anne

2013-01-01

Body size is a key sexually selected trait in many animal species. If size imposes a physical limit on the production of loud low-frequency sounds, then low-pitched vocalisations could act as reliable signals of body size. However, the central prediction of this hypothesis – that the pitch of vocalisations decreases with size among competing individuals – has limited support in songbirds. One reason could be that only the lowest-frequency components of vocalisations are constrained, and this may go unnoticed when vocal ranges are large. Additionally, the constraint may only be apparent in contexts when individuals are indeed advertising their size. Here we explicitly consider signal diversity and performance limits to demonstrate that body size limits song frequency in an advertising context in a songbird. We show that in purple-crowned fairy-wrens, Malurus coronatus coronatus, larger males sing lower-pitched low-frequency advertising songs. The lower frequency bound of all advertising song types also has a significant negative relationship with body size. However, the average frequency of all their advertising songs is unrelated to body size. This comparison of different approaches to the analysis demonstrates how a negative relationship between body size and song frequency can be obscured by failing to consider signal design and the concept of performance limits. Since these considerations will be important in any complex communication system, our results imply that body size constraints on low-frequency vocalisations could be more widespread than is currently recognised. PMID:23437221

Testing the 'island rule' for a tenebrionid beetle (Coleoptera, Tenebrionidae)

NASA Astrophysics Data System (ADS)

Palmer, Miquel

2002-05-01

Insular populations and their closest mainland counterparts commonly display body size differences that are considered to fit the island rule, a theoretical framework to explain both dwarfism and gigantism in isolated animal populations. The island rule is used to explain the pattern of change of body size at the inter-specific level. But the model implicitly makes also a prediction for the body size of isolated populations of a single species. It suggests that, for a hypothetical species covering a wide range of island sizes, there exists a specific island size where this species reaches the largest body size. Body size would be small (in relative terms) in the smallest islets of the species range. It would increase with island size, and reach a maximum at some specific island size. However, additional increases from such a specific island size would instead promote body size reduction, and small (in relative terms) body sizes would be found again on the largest islands. The biogeographical patterns predicted by the island rule have been described and analysed for vertebrates only (mainly mammals), but remain largely untested for insects or other invertebrates. I analyse here the pattern of body size variation between seven isolated insular populations of a flightless beetle, Asida planipennis (Coleoptera, Tenebrionidae). This is an endemic species of Mallorca, Menorca and a number of islands and islets in the Balearic archipelago (western Mediterranean). The study covers seven of the 15 known populations (i.e., there are only 15 islands or islets inhabited by the species). The populations studied fit the pattern advanced above and we could, therefore, extrapolate the island rule to a very different kind of organism. However, the small sample size of some of the populations invites some caution at this early stage.

Stance control is not affected by paresis and reflex hyperexcitability: the case of spastic patients

PubMed Central

Nardone, A; Galante, M; Lucas, B; Schieppati, M

2001-01-01

OBJECTIVES—Spastic patients were studied to understand whether stance unsteadiness is associated with changes in the control of voluntary force, muscle tone, or reflex excitability, rather than to abnormal posture connected to the motor deficit itself.
METHODS—Twenty four normal subjects, 12 patients affected by amyotrophic lateral sclerosis (ALS), seven by spastic paraparesis, and 14 by hemiparesis were studied. All patients featured various degrees of spasticity and paresis but were free from clinically evident sensory deficits. Body sway during quiet upright stance was assessed through a stabilometric platform under both eyes open (EO) and eyes closed (EC) conditions. The sudden rotation of a supporting platform, in a toe up and toe down direction respectively, evoked short (SLR) and medium latency (MLR) reflex responses to stretch of the soleus or the tibialis anterior (TA) muscle.
RESULTS—No relation was found between clinical findings (tone, muscle strength, tendon reflexes, plantar response, and duration of disease) and body sway. On average, all patient groups exhibited a forward shift of the centre of foot pressure (CFP) with respect to normal subjects; in addition, paraparetic and to a much larger extent hemiparetic patients showed a lateral shift of CFP. Body sway area was significantly increased only in the hemiparetic patients. No relation was found between position of the CFP and sway within any patient group. Soleus SLR was increased in all patients with respect to normal subjects. TA SLR was often seen in both patients with ALS and paraparetic patients, but only rarely in normal subjects and hemiparetic patients. However, no relation was found between amplitude of soleus or TA SLRs and stabilometric variables. The frequency and size of soleus MLR and TA MLR were decreased in all patients. These responses were decreased in size and not modulated by background EMG in the affected leg of hemiparetic patients, suggesting a disturbed control of spinal reflexes fed by spindle group II afferent fibres.
CONCLUSIONS—It is proposed that body posture, paresis, or monosynaptic reflex hyperexcitability do not affect the control of equilibrium during quiet upright stance. In hemiparetic patients, the decreased amplitude of MLRs might be the main cause of the large postural instability. The results are congruent with the hypothesis of a role for group II afferent input in the reflex control of equilibrium.

 PMID:11309458

Smaller predator-prey body size ratios in longer food chains.

PubMed Central

Jennings, Simon; Warr, Karema J

2003-01-01

Maximum food-chain length has been correlated with resource availability, ecosystem size, environmental stability and colonization history. Some of these correlations may result from environmental effects on predator-prey body size ratios. We investigate relationships between maximum food-chain length, predator-prey mass ratios, primary production and environmental stability in marine food webs with a natural history of community assembly. Our analyses provide empirical evidence that smaller mean predator-prey body size ratios are characteristic of more stable environments and that food chains are longer when mean predator-prey body size ratios are small. We conclude that environmental effects on predator-prey body size ratios contribute to observed differences in maximum food-chain length. PMID:12965034

Long-Term Excessive Body Weight and Adult Left Ventricular Hypertrophy Are Linked Through Later-Life Body Size and Blood Pressure: The Bogalusa Heart Study.

PubMed

Zhang, Huijie; Zhang, Tao; Li, Shengxu; Guo, Yajun; Shen, Wei; Fernandez, Camilo; Harville, Emily; Bazzano, Lydia A; Urbina, Elaine M; He, Jiang; Chen, Wei

2017-05-12

Childhood adiposity is associated with cardiac structure in later life, but little is known regarding to what extent childhood body weight affects adult left ventricular geometric patterns through adult body size and blood pressure (BP). Determine quantitatively the mediation effect of adult body weight and BP on the association of childhood body mass index (BMI) with adult left ventricular (LV) hypertrophy. This longitudinal study consisted of 710 adults, aged 26 to 48 years, who had been examined for BMI and BP measured ≥4× during childhood and ≥2× during adulthood, with a mean follow-up period of 28.0 years. After adjusting for age, race, and sex, adult BMI had a significant mediation effect (76.4%; P <0.01) on the childhood BMI-adult LV mass index association. The mediation effects of adult systolic BP (15.2%), long-term burden (12.1%), and increasing trends of systolic BP (7.9%) were all significant ( P <0.01). Furthermore, these mediators also had significant mediation effects on the association of childhood BMI with adult LV hypertrophy, eccentric hypertrophy, and concentric hypertrophy. Importantly, the mediation effects of adult BMI were all significantly stronger than those of adult systolic BP on LV mass index, LV hypertrophy, and LV remodeling patterns ( P <0.01). Additionally, the mediation effect of systolic BP on concentric hypertrophy was significantly stronger than that on eccentric hypertrophy ( P <0.01). These findings suggest that increased childhood BMI has long-term adverse impact on subclinical changes in adult cardiac structure, and early life excessive body weight and adult LV hypertrophy are linked through later life excessive body weight and elevated BP. © 2017 American Heart Association, Inc.

Influence of Urbanization on Body Size, Condition, and Physiology in an Urban Exploiter: A Multi-Component Approach

PubMed Central

Meillère, Alizée; Brischoux, François; Parenteau, Charline; Angelier, Frédéric

2015-01-01

Consistent expanding urbanization dramatically transforms natural habitats and exposes organisms to novel environmental challenges, often leading to reduced species richness and diversity in cities. However, it remains unclear how individuals are affected by the urban environment and how they can or cannot adjust to the specific characteristics of urban life (e.g. food availability). In this study, we used an integrative multi-component approach to investigate the effects of urbanization on the nutritional status of house sparrows (Passer domesticus). We assessed several morphological and physiological indices of body condition in both juveniles (early post-fledging) and breeding adults from four sites with different levels of urbanization in France, Western Europe. We found that sparrows in more urbanized habitats have reduced body size and body mass compared to their rural conspecifics. However, we did not find any consistent differences in a number of complementary indices of condition (scaled mass index, muscle score, hematocrit, baseline and stress-induced corticosterone levels) between urban and rural birds, indicating that urban sparrows may not be suffering nutritional stress. Our results suggest that the urban environment is unlikely to energetically constrain adult sparrows, although other urban-related variables may constrain them. On the other hand, we found significant difference in juvenile fat scores, suggesting that food types provided to young sparrows differed highly between habitats. In addition to the observed smaller size of urban sparrows, these results suggest that the urban environment is inadequate to satisfy early-life sparrows’ nutritional requirements, growth, and development. The urban environment may therefore have life-long consequences for developing birds. PMID:26270531

Influence of Urbanization on Body Size, Condition, and Physiology in an Urban Exploiter: A Multi-Component Approach.

PubMed

Meillère, Alizée; Brischoux, François; Parenteau, Charline; Angelier, Frédéric

2015-01-01

Consistent expanding urbanization dramatically transforms natural habitats and exposes organisms to novel environmental challenges, often leading to reduced species richness and diversity in cities. However, it remains unclear how individuals are affected by the urban environment and how they can or cannot adjust to the specific characteristics of urban life (e.g. food availability). In this study, we used an integrative multi-component approach to investigate the effects of urbanization on the nutritional status of house sparrows (Passer domesticus). We assessed several morphological and physiological indices of body condition in both juveniles (early post-fledging) and breeding adults from four sites with different levels of urbanization in France, Western Europe. We found that sparrows in more urbanized habitats have reduced body size and body mass compared to their rural conspecifics. However, we did not find any consistent differences in a number of complementary indices of condition (scaled mass index, muscle score, hematocrit, baseline and stress-induced corticosterone levels) between urban and rural birds, indicating that urban sparrows may not be suffering nutritional stress. Our results suggest that the urban environment is unlikely to energetically constrain adult sparrows, although other urban-related variables may constrain them. On the other hand, we found significant difference in juvenile fat scores, suggesting that food types provided to young sparrows differed highly between habitats. In addition to the observed smaller size of urban sparrows, these results suggest that the urban environment is inadequate to satisfy early-life sparrows' nutritional requirements, growth, and development. The urban environment may therefore have life-long consequences for developing birds.

Linking body mass and group dynamics in an obligate cooperative breeder.

PubMed

Ozgul, Arpat; Bateman, Andrew W; English, Sinead; Coulson, Tim; Clutton-Brock, Tim H

2014-11-01

Social and environmental factors influence key life-history processes and population dynamics by affecting fitness-related phenotypic traits such as body mass. The role of body mass is particularly pronounced in cooperative breeders due to variation in social status and consequent variation in access to resources. Investigating the mechanisms underlying variation in body mass and its demographic consequences can help elucidate how social and environmental factors affect the dynamics of cooperatively breeding populations. In this study, we present an analysis of the effect of individual variation in body mass on the temporal dynamics of group size and structure of a cooperatively breeding mongoose, the Kalahari meerkat, Suricata suricatta. First, we investigate how body mass interacts with social (dominance status and number of helpers) and environmental (rainfall and season) factors to influence key life-history processes (survival, growth, emigration and reproduction) in female meerkats. Next, using an individual-based population model, we show that the models explicitly including individual variation in body mass predict group dynamics better than those ignoring this morphological trait. Body mass influences group dynamics mainly through its effects on helper emigration and dominant reproduction. Rainfall has a trait-mediated, destabilizing effect on group dynamics, whereas the number of helpers has a direct and stabilizing effect. Counteracting effects of number of helpers on different demographic rates, despite generating temporal fluctuations, stabilizes group dynamics in the long term. Our study demonstrates that social and environmental factors interact to produce individual variation in body mass and accounting for this variation helps to explain group dynamics in this cooperatively breeding population. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

Identification of differentially expressed genes associated with differential body size in mandarin fish (Siniperca chuatsi).

PubMed

Tian, Changxu; Li, Ling; Liang, Xu-Fang; He, Shan; Guo, Wenjie; Lv, Liyuan; Wang, Qingchao; Song, Yi

2016-08-01

Body size is an obvious and important characteristic of fish. Mandarin fish Siniperca chuatsi (Basilewsky) is one of the most valuable perciform species widely cultured in China. Individual differences in body size are common in mandarin fish and significantly influence the aquaculture production. However, little is currently known about its genetic control. In this study, digital gene expression profiling and transcriptome sequencing were performed in mandarin fish with differential body size at 30 and 180 days post-hatch (dph), respectively. Body weight, total length and body length of fish with big-size were significantly higher than those with small-size at both 30 and 180 dph (P < 0.05). 2171 and 2014 differentially expressed genes were identified between small-size and big-size fish at 30 and 180 dph, respectively. RT quantitative PCR (qPCR) analysis showed that the differential expression of 10 selected genes in mandarin fish that went through the same training procedure. The genes were involved in the growth hormone-insulin-like growth factor axis, cell proliferation and differentiation, appetite control, glucose metabolism, reproduction and sexual size dimorphism pathways. This study will help toward a comprehensive understanding of the complexity of regulation of body size in mandarin fish individuals and provide valuable information for future research.

Rule reversal: Ecogeographical patterns of body size variation in the common treeshrew (Mammalia, Scandentia)

USGS Publications Warehouse

Sargis, Eric J.; Millien, Virginie; Woodman, Neal; Olson, Link E.

2018-01-01

There are a number of ecogeographical “rules” that describe patterns of geographical variation among organisms. The island rule predicts that populations of larger mammals on islands evolve smaller mean body size than their mainland counterparts, whereas smaller‐bodied mammals evolve larger size. Bergmann's rule predicts that populations of a species in colder climates (generally at higher latitudes) have larger mean body sizes than conspecifics in warmer climates (at lower latitudes). These two rules are rarely tested together and neither has been rigorously tested in treeshrews, a clade of small‐bodied mammals in their own order (Scandentia) broadly distributed in mainland Southeast Asia and on islands throughout much of the Sunda Shelf. The common treeshrew, Tupaia glis, is an excellent candidate for study and was used to test these two rules simultaneously for the first time in treeshrews. This species is distributed on the Malay Peninsula and several offshore islands east, west, and south of the mainland. Using craniodental dimensions as a proxy for body size, we investigated how island size, distance from the mainland, and maximum sea depth between the mainland and the islands relate to body size of 13 insular T. glis populations while also controlling for latitude and correlation among variables. We found a strong negative effect of latitude on body size in the common treeshrew, indicating the inverse of Bergmann's rule. We did not detect any overall difference in body size between the island and mainland populations. However, there was an effect of island area and maximum sea depth on body size among island populations. Although there is a strong latitudinal effect on body size, neither Bergmann's rule nor the island rule applies to the common treeshrew. The results of our analyses demonstrate the necessity of assessing multiple variables simultaneously in studies of ecogeographical rules.

Maintenance of phenotypic variation: Repeatability, heritability and size-dependent processes in a wild brook trout population

USGS Publications Warehouse

Letcher, B.H.; Coombs, J.A.; Nislow, K.H.

2011-01-01

Phenotypic variation in body size can result from within-cohort variation in birth dates, among-individual growth variation and size-selective processes. We explore the relative effects of these processes on the maintenance of wide observed body size variation in stream-dwelling brook trout (Salvelinus fontinalis). Based on the analyses of multiple recaptures of individual fish, it appears that size distributions are largely determined by the maintenance of early size variation. We found no evidence for size-dependent compensatory growth (which would reduce size variation) and found no indication that size-dependent survival substantially influenced body size distributions. Depensatory growth (faster growth by larger individuals) reinforced early size variation, but was relatively strong only during the first sampling interval (age-0, fall). Maternal decisions on the timing and location of spawning could have a major influence on early, and as our results suggest, later (>age-0) size distributions. If this is the case, our estimates of heritability of body size (body length=0.25) will be dominated by processes that generate and maintain early size differences. As a result, evolutionary responses to environmental change that are mediated by body size may be largely expressed via changes in the timing and location of reproduction. Published 2011. This article is a US Government work and is in the public domain in the USA.

Body size affects the evolution of hidden colour signals in moths.

PubMed

Kang, Changku; Zahiri, Reza; Sherratt, Thomas N

2017-08-30

Many cryptic prey have also evolved hidden contrasting colour signals which are displayed to would-be predators. Given that these hidden contrasting signals may confer additional survival benefits to the prey by startling/intimidating predators, it is unclear why they have evolved in some species, but not in others. Here, we have conducted a comparative phylogenetic analysis of the evolution of colour traits in the family Erebidae (Lepidoptera), and found that the hidden contrasting colour signals are more likely to be found in larger species. To understand why this relationship occurs, we present a general mathematical model, demonstrating that selection for a secondary defence such as deimatic display will be stronger in large species when (i) the primary defence (crypsis) is likely to fail as its body size increases and/or (ii) the secondary defence is more effective in large prey. To test the model assumptions, we conducted behavioural experiments using a robotic moth which revealed that survivorship advantages were higher against wild birds when the moth has contrasting hindwings and large size. Collectively, our results suggest that the evolutionary association between large size and hidden contrasting signals has been driven by a combination of the need for a back-up defence and its efficacy. © 2017 The Author(s).

Determinants and consequences of female attractiveness and sexiness: realistic tests with restaurant waitresses.

PubMed

Lynn, Michael

2009-10-01

Waitresses completed an on-line survey about their physical characteristics, self-perceived attractiveness and sexiness, and average tips. The waitresses' self-rated physical attractiveness increased with their breast sizes and decreased with their ages, waist-to-hip ratios, and body sizes. Similar effects were observed on self-rated sexiness, with the exception of age, which varied with self-rated sexiness in a negative, quadratic relationship rather than a linear one. Moreover, the waitresses' tips varied with age in a negative, quadratic relationship, increased with breast size, increased with having blond hair, and decreased with body size. These findings, which are discussed from an evolutionary perspective, make several contributions to the literature on female physical attractiveness. First, they replicate some previous findings regarding the determinants of female physical attractiveness using a larger, more diverse, and more ecologically valid set of stimuli than has been studied before. Second, they provide needed evidence that some of those determinants of female beauty affect interpersonal behaviors as well as attractiveness ratings. Finally, they indicate that some determinants of female physical attractiveness do not have the same effects on overt interpersonal behavior (such as tipping) that they have on attractiveness ratings. This latter contribution highlights the need for more ecologically valid tests of evolutionary theories about the determinants and consequences of female beauty.

Energetic tradeoffs control the size distribution of aquatic mammals

NASA Astrophysics Data System (ADS)

Gearty, William; McClain, Craig R.; Payne, Jonathan L.

2018-04-01

Four extant lineages of mammals have invaded and diversified in the water: Sirenia, Cetacea, Pinnipedia, and Lutrinae. Most of these aquatic clades are larger bodied, on average, than their closest land-dwelling relatives, but the extent to which potential ecological, biomechanical, and physiological controls contributed to this pattern remains untested quantitatively. Here, we use previously published data on the body masses of 3,859 living and 2,999 fossil mammal species to examine the evolutionary trajectories of body size in aquatic mammals through both comparative phylogenetic analysis and examination of the fossil record. Both methods indicate that the evolution of an aquatic lifestyle is driving three of the four extant aquatic mammal clades toward a size attractor at ˜500 kg. The existence of this body size attractor and the relatively rapid selection toward, and limited deviation from, this attractor rule out most hypothesized drivers of size increase. These three independent body size increases and a shared aquatic optimum size are consistent with control by differences in the scaling of energetic intake and cost functions with body size between the terrestrial and aquatic realms. Under this energetic model, thermoregulatory costs constrain minimum size, whereas limitations on feeding efficiency constrain maximum size. The optimum size occurs at an intermediate value where thermoregulatory costs are low but feeding efficiency remains high. Rather than being released from size pressures, water-dwelling mammals are driven and confined to larger body sizes by the strict energetic demands of the aquatic medium.

After runaway: The trans-Hill stage of planetesimal growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lithwick, Yoram

2014-01-01

When planetesimals begin to grow by coagulation, they first enter an epoch of runaway, during which the biggest bodies grow faster than all the others. The questions of how runaway ends and what comes next have not been answered satisfactorily. We show that runaway is followed by a new stage—the 'trans-Hill stage'—that commences when the bodies that dominate viscous stirring ('big bodies') become trans-Hill, i.e., when their Hill velocity matches the random speed of the small bodies they accrete. Subsequently, the small bodies' random speed grows in lockstep with the big bodies' sizes, such that the system remains in themore » trans-Hill state. Trans-Hill growth is crucial for determining the efficiency of growing big bodies, as well as their growth timescale and size spectrum. Trans-Hill growth has two sub-stages. In the earlier one, which occurs while the stirring bodies remain sufficiently small, the evolution is collisionless, i.e., collisional cooling among all bodies is irrelevant. The efficiency of forming big bodies in this collisionless sub-stage is very low, ∼10α << 1, where α ∼ 0.005(a/AU){sup –1} is the ratio between the physical size of a body and its Hill radius. Furthermore, the size spectrum is flat (equal mass per size decade, i.e., q = 4). This collisionless trans-Hill solution explains results from previous coagulation simulations for both the Kuiper Belt and the asteroid belt. The second trans-Hill sub-stage commences once the stirring bodies grow big enough (>α{sup –1} × the size of the accreted small bodies). After that time, collisional cooling among small bodies controls the evolution. The efficiency of forming big bodies rises and the size spectrum becomes more top heavy. Trans-Hill growth can terminate in one of two ways, depending on the sizes of the small bodies. First, mutual accretion of big bodies can become significant and conglomeration proceeds until half of the total mass is converted into big bodies. This mode of growth may explain the observed size distributions of small bodies in the solar system and is explored in our subsequent work. Second, if the big bodies' orbits become separated by their Hill radius, oligarchy commences. This mode likely precedes the formation of fully fledged planets.« less

Body shape throughout life and correlations with IGFs and GH.

PubMed

Schernhammer, Eva S; Tworoger, Shelley S; Eliassen, A Heather; Missmer, Stacey A; Holly, Jeff M; Pollak, Michael N; Hankinson, Susan E

2007-09-01

Both insulin-like growth factors (IGF) and body size have been linked to premenopausal breast cancer risk. However, observational studies of IGF have not been consistent, and they suggest that perhaps earlier levels of IGF might be more strongly related to breast cancer than those measured at mid-age. We therefore sought to explore associations between several measures of body size throughout life and IGF levels in premenopausal women. We examined cross-sectional associations of birth weight, body shape (or somatotype) at ages 5 and 10, body mass index (BMI) at age 18 and adulthood, bra cup size at age 20, adult waist circumference and waist-to-hip ratio (WHR), and attained height with plasma levels of IGF-I, IGF binding protein 3 (IGFBP-3), IGFBP-1, and GH. Participants were 592 healthy premenopausal women aged 34-52 from the Nurses' Health Study II. Using multiple linear regression, we computed least-square mean hormone levels across the categories of early life anthropometric factors. We observed consistent and strong inverse associations between body shape at various stages in life and IGF levels. Somatotype at ages 5 and 10 was inversely associated with IGF-I (P for difference, < 0.01) and positively with IGFBP-3 measured later in adulthood. Further, comparing women with a BMI > or = 25 kg/m(2) at age 18 vs < 19 kg/m(2), similar associations were observed for IGF-I (P for trend, 0.005) and IGFBP-3 (P for trend, 0.01), which were even stronger for BMI at blood collection (BMI< 20 versus BMI > or = 30, mean IGF-I 254 ng/ml, 95% CI, 239-271 vs 208 ng/ml, 95% CI, 195-222). Both waist circumference and WHR were strongly and inversely related to IGFBP-1 levels (top versus bottom quartile of waist circumference: 14.5 vs 40.0 ng/ml, P for trend 0.0005; WHR: 18.3 vs 39.4 ng/ml, P for trend 0.002), with similar results for bra cup size at age 20 although they did not reach statistical significance. There was no association between height and IGF or GH levels. Birth weight, on the other hand, was weakly positively associated with both IGF-I and IGFBP-1 levels, and inversely with GH. Our results suggest that childhood and adult body size may affect premenopausal breast cancer risk differently than birth weight, through associations with IGF and GH levels.

Allometric relationship of postmolt net ion uptake, ventilation, and circulation in the freshwater crayfish Procambarus clarkii: intraspecific scaling.

PubMed

Zanotto, F P; Wheatly, M G; Reiber, C L; Gannon, A T; Jalles-Filho, E

2004-01-01

There are few intraspecific studies relating physiological parameters to body mass. This study relates scaling of ionic regulation and respiratory parameters with body mass in crayfish (Procambarus clarkii). These animals were chosen because of their direct development, spanning four orders of magnitude in body mass. Usually, these animals are hyperregulators and must maintain hemolymph electrolyte levels above those in the ambient freshwater. This is especially important in the postmolt, when ion imbalance can occur. Maintaining hemolymph ion levels above ambient involves active processes that are independently related to metabolic rate, ventilation, and circulation. Therefore, this study investigates relationships among size and ionic regulation, heart rate, and ventilation in crayfish, spanning a size range of 0.003-24 g. Postmolt net ion uptake of Ca, titratable base, Na, Cl, and NH4 increase with body mass (positive allometry) with slopes of 0.92, 0.79, 0.90, 0.84, and 0.87, respectively. Between 72% and 97% of variation in ionic regulation was related to body mass. The slopes differed from each other for Ca and titratable base but not for Na, Cl, and NH4. For heart rate and ventilation rate, different relationships were derived for animals smaller and larger than 0.01 g (between first and third instar). Animals larger than 0.01 g show a negative allometric relationship between heart rate and body size ([body mass](0.15)), while smaller animals show positive allometry with body size, but only 29% of variation in heart rate is explained by body size alone. For ventilation rates, the negative allometry with body size for animals larger than 0.01 g is present, but less than 15% of variation in ventilation rate is explained by size, while for smaller animals the size dependency disappears. Based on these results, predictions of physiological parameters such as ionic regulation based on body size are useful in crayfish, but estimates of respiratory parameters and body size should be used with caution.

Trade-offs between larval survival and adult ornament development depend on predator regime in a territorial dragonfly.

PubMed

Moore, Michael P; Martin, Ryan A

2018-05-28

Trade-offs between juvenile survival and the development of sexually selected traits can cause ontogenetic conflict between life stages that constrains adaptive evolution. However, the potential for ecological interactions to alter the presence or strength of these trade-offs remains largely unexplored. Antagonistic selection over the accumulation and storage of resources could be one common cause of environment-specific trade-offs between life stages: higher condition may simultaneously enhance adult ornament development and increase juvenile vulnerability to predators. We tested this hypothesis in an ornamented dragonfly (Pachydiplax longipennis). Higher larval body condition indeed enhanced the initial development of its intrasexually selected wing coloration, but was opposed by viability selection in the presence of large aeshnid predators. In contrast, viability selection did not oppose larval body condition in pools when aeshnids were absent, and was not affected when we manipulated cannibalism risk. Trade-offs between larval survival and ornament development, mediated through the conflicting effects of body condition, therefore occurred only under high predation risk. We additionally characterized how body condition influences several traits associated with predator avoidance. Although body condition did not affect burst distance, it did increase larval abdomen size, potentially making larvae easier targets for aeshnid predators. As high body condition similarly increases vulnerability to predators in many other animals, predator-mediated costs of juvenile resource accumulation could be a common, environment-specific limitation on the elaboration of sexually selected traits.

Influence of maturation on anthropometry and body composition in Japanese junior high school students.

PubMed

Fukunaga, Yuko; Takai, Yohei; Yoshimoto, Takaya; Fujita, Eiji; Yamamoto, Masayoshi; Kanehisa, Hiroaki

2013-03-12

The purpose of this study was to examine maturity-related differences in anthropometry and body composition in Japanese youth within a single year. Two hundred and ten Japanese youth aged from 13 to 13.99 years participated in this study. Their maturity status was assessed using a self-assessment of stage of pubic hair development. Bioelectrical impedance analysis was used to estimate percent body fat and lean body mass (LBM). Muscle thickness of the anterior thigh, posterior lower leg and rectus abdominis muscles were measured by ultrasound. For boys, height, body weight, and LBM in less mature groups were lower than that in more mature groups. The maturity-related differences were still significant after adjusting for chronological age. On the other hand, muscle thickness values in the lower extremity and abdomen differed among the groups at different stages of pubic hair development, whereas there was no maturity-related difference in the relative values corrected by LBM, except for those thickness values measured at the abdomen. For girls, only the muscle thickness at the anterior thigh and muscle thickness relative to LBM1/3 at the posterior lower leg was significantly affected by maturity status, but significant maturity-related difference was not found after adjusting for chronological age. At least for Japanese boys and girls aged 13 years, maturity status affected body size in boys, but not in girls, and the influence of maturation on the muscularity of the lower extremity and trunk muscles is less in both sexes.

Evaluation of factors that affect hip moment impulse during gait: A systematic review.

PubMed

Inai, Takuma; Takabayashi, Tomoya; Edama, Mutsuaki; Kubo, Masayoshi

2018-03-01

Decreasing the daily cumulative hip moments in the frontal and sagittal planes may lower the risk of hip osteoarthritis. Therefore, it may be important to evaluate factors that affect hip moment impulse during gait. It is unclear what factors affect hip moment impulse during gait. This systematic review aimed to evaluate different factors that affect hip moment impulse during gait in healthy adults and patients with hip osteoarthritis. Four databases (Scopus, ScienceDirect, PubMed, and PEDro) were searched up to August 2017 to identify studies that examined hip moment impulse during gait. Data extracted for analysis included the sample size, age, height, body mass, type of intervention, and main findings. After screening, 10 of the 975 studies identified were included in our analysis. Several factors, including a rocker bottom shoe, FitFlop™ sandals, ankle push-off, posture, stride length, body-weight unloading, a rollator, walking poles, and a knee brace, were reviewed. The main findings were as follows: increasing ankle push-off decreased both the hip flexion and extension moment impulses; body-weight unloading decreased both the hip extension and adduction moment impulses; the FitFlop™ sandal increased the sum of the hip flexion and extension moment impulses; long strides increased the hip extension moment impulse; and the use of a knee brace increased hip flexion moment impulse. Of note, none of the eligible studies included patients with hip osteoarthritis. The hip moment impulses can be modified by person-specific factors (ankle push-off and long strides) and external factors (body-weight unloading and use of the FitFlop™ sandals and a knee brace). Effects on the progression of hip osteoarthritis remain to be evaluated. Copyright © 2018 Elsevier B.V. All rights reserved.

Carcass weight, growth performance and internal organs size of broilers fed graded levels of Saccharomycese cervicia supplemented diets.

PubMed

Farhoomand, Parviz; Dadvend, Ali

2007-06-01

The effects of graded levels of Saccharomyces cerviciae (SC) on performance, carcass characteristic and internal organs size of broilers were investigated in a seven weeks trial using 160 days old Cab 500 mal broiler chicks fed corn-soybean meal based diet. In a completely randomized design 160 chicks distributed to four dietary treatments. Thus each dietary treatment had 4 replication with 10 birds each. Four dietary treatment according to the Saccharomyces cervicia (SC) levels were S (0), S1 (100), S2 (300) and S3 (500 g kg(-1) diet). Each three levels of SC significantly (p < 0.05) affected the Feed Conversion Rate (FCR), during 7-21 days and S3 showed the best FCR but during 21-42 days the S1 was the best (p < 0.05). There was no significance differences in body weight gain (BW) and Feed Intake (FI) between the treatments. SC supplementation did not significantly (p > 0.05) affect Dressing Yield (DY) but dressing yield in SC containing treatments numerically were higher than control. Inclusion and levels of SC significantly (p < 0.05) affected, liver, spleen and Abdominal Fat (AF) weight. As the level of SC in diets increased the liver and spleen weight increased too. But abdominal fat decreased. Supplementation of SC significantly (p < 0.05) affected the intestinal (Large and Small) length (LI, SI), the shortest intestine measured on S3 receiving diet, while the highest intestine measured on bird receiving the control diet. The results demonstrated that compared to control diet supplemental SC significantly (p < 0.05) improve FCR, decrease abdominal fat, intestine length and apparently increase body weight gain, dressing yield, liver and spleen weights and 100 g kg(-1) SC diet give the best.

Inter-class competition in stage-structured populations: effects of adult density on life-history traits of adult and juvenile common lizards.

PubMed

San-Jose, Luis M; Peñalver-Alcázar, Miguel; Huyghe, Katleen; Breedveld, Merel C; Fitze, Patrick S

2016-12-01

Ecological and evolutionary processes in natural populations are largely influenced by the population's stage-structure. Commonly, different classes have different competitive abilities, e.g., due to differences in body size, suggesting that inter-class competition may be important and largely asymmetric. However, experimental evidence states that inter-class competition, which is important, is rare and restricted to marine fish. Here, we manipulated the adult density in six semi-natural populations of the European common lizard, Zootoca vivipara, while holding juvenile density constant. Adult density affected juveniles, but not adults, in line with inter-class competition. High adult density led to lower juvenile survival and growth before hibernation. In contrast, juvenile survival after hibernation was higher in populations with high adult density, pointing to relaxed inter-class competition. As a result, annual survival was not affected by adult density, showing that differences in pre- and post-hibernation survival balanced each other out. The intensity of inter-class competition affected reproduction, performance, and body size in juveniles. Path analyses unravelled direct treatment effects on early growth (pre-hibernation) and no direct treatment effects on the parameters measured after hibernation. This points to allometry of treatment-induced differences in early growth, and it suggests that inter-class competition mainly affects the early growth of the competitively inferior class and thereby their future performance and reproduction. These results are in contrast with previous findings and, together with results in marine fish, suggest that the strength and direction of density dependence may depend on the degree of inter-class competition, and thus on the availability of resources used by the competing classes.

Meteoroid Impacts: A Competitor for Yarkovsky and YORP

NASA Astrophysics Data System (ADS)

Wiegert, Paul

2014-11-01

Meteoroids impacting an asteroid transfer linear and angular momentum to the larger body, which may change its orbit and its rotational state. The meteoroid environment of our Solar System may affect small (few meter sizes and smaller) asteroids at a level that is comparable to the Yarkovsky and Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects.Asteroids orbiting on prograde orbits near the Earth encounter an anisotropic meteoroid environment, including a population of particles on retrograde orbits generally accepted to be material from long-period comets spiralling inwards under Poynting-Robertson drag. High relative speed (60 km/s) impacts by meteoroids provide a small effective drag force that decreases asteroid semimajor axes and which is independent of their rotation pole. This effect may exceed the Yarkovsky drift at sizes near and below one meter.The momentum content of the meteoroids themselves is small enough to neglect, but it is the momentum transport by ejecta that increases the net effective force by two orders of magnitude for impacts into bare rock surfaces: this brings the effect to a level where it is of order that due to Yarkovsky, at least for small bodies. However, the above results are sensitive to the extrapolation of laboratory microcratering experiment results to real meteoroid-asteroid collisions and need further study.Meteoroid impacts may also affect asteroid spins at a level comparable to that of YORP at sizes smaller than tens of meters. However, we conclude that recent measurements of the YORP effect have probably not been compromised, because of the targets' large sizes and because they are known or likely to be regolith-covered rather than bare rock, which decreases the efficiency of ejecta production. However, the effect of impacts increases sharply with decreasing size, and may be important for asteroids smaller than a few tens of meters in radius.

Life-History Evolution on Tropidurinae Lizards: Influence of Lineage, Body Size and Climate

PubMed Central

Brandt, Renata; Navas, Carlos A.

2011-01-01

The study of life history variation is central to the evolutionary theory. In many ectothermic lineages, including lizards, life history traits are plastic and relate to several sources of variation including body size, which is both a factor and a life history trait likely to modulate reproductive parameters. Larger species within a lineage, for example tend to be more fecund and have larger clutch size, but clutch size may also be influenced by climate, independently of body size. Thus, the study of climatic effects on lizard fecundity is mandatory on the current scenario of global climatic change. We asked how body and clutch size have responded to climate through time in a group of tropical lizards, the Tropidurinae, and how these two variables relate to each other. We used both traditional and phylogenetic comparative methods. Body and clutch size are variable within Tropidurinae, and both traits are influenced by phylogenetic position. Across the lineage, species which evolved larger size produce more eggs and neither trait is influenced by temperature components. A climatic component of precipitation, however, relates to larger female body size, and therefore seems to exert an indirect relationship on clutch size. This effect of precipitation on body size is likely a correlate of primary production. A decrease in fecundity is expected for Tropidurinae species on continental landmasses, which are predicted to undergo a decrease in summer rainfall. PMID:21603641

Body size-dependent Cd accumulation in the zebra mussel Dreissena polymorpha from different routes.

PubMed

Tang, Wen-Li; Evans, Douglas; Kraemer, Lisa; Zhong, Huan

2017-02-01

Understanding body size-dependent metal accumulation in aquatic organisms (i.e., metal allometry) is critical in interpreting biomonitoring data. While growth has received the most attention, little is known about controls of metal exposure routes on metal allometry. Here, size-dependent Cd accumulation in zebra mussels (Dreissena polymorpha) from different routes were investigated by exposing mussels to A.( 111 Cd spiked algae+ 113 Cd spiked river water) or B.( 111 Cd spiked sediments+ 113 Cd spiked river water). After exposure, 111 Cd or 113 Cd levels in mussel tissue were found to be negatively correlated with tissue weight, while Cd allometry coefficients (b values) were dependent on Cd exposure routes: -0.664 for algae, -0.241 for sediments and -0.379 for river water, compared to -0.582 in un-exposed mussels. By comparing different Cd exposure routes, we found that size-dependent Cd bioaccumulation from algae or river water could be more responsible for the overall size-dependent Cd accumulation in mussels, and the relative importance of the two sources was dependent on mussel size ranges: Cadmium obtained from algae (algae-Cd) was more important in size-dependent Cd accumulation in smaller mussels (tissue dry weight < 5 mg), while river water-Cd became more important in larger individuals (tissue dry weight > 5 mg). In contrast, sediment-Cd contributed only a small amount to Cd accumulation in zebra mussels and may have little effect on size-dependent Cd bioaccumulation. Our results suggest that size-dependent Cd accumulation in mussels could be largely affected by exposure routes, which should be considered when trying to interpret Cd biomonitoring data of zebra mussels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diatom cell size, coloniality and motility: trade-offs between temperature, salinity and nutrient supply with climate change.

PubMed

Svensson, Filip; Norberg, Jon; Snoeijs, Pauline

2014-01-01

Reduction in body size has been proposed as a universal response of organisms, both to warming and to decreased salinity. However, it is still controversial if size reduction is caused by temperature or salinity on their own, or if other factors interfere as well. We used natural benthic diatom communities to explore how "body size" (cells and colonies) and motility change along temperature (2-26°C) and salinity (0.5-7.8) gradients in the brackish Baltic Sea. Fourth-corner analysis confirmed that small cell and colony sizes were associated with high temperature in summer. Average community cell volume decreased linearly with 2.2% per °C. However, cells were larger with artificial warming when nutrient concentrations were high in the cold season. Average community cell volume increased by 5.2% per °C of artificial warming from 0 to 8.5°C and simultaneously there was a selection for motility, which probably helped to optimize growth rates by trade-offs between nutrient supply and irradiation. Along the Baltic Sea salinity gradient cell size decreased with decreasing salinity, apparently mediated by nutrient stoichiometry. Altogether, our results suggest that climate change in this century may polarize seasonality by creating two new niches, with elevated temperature at high nutrient concentrations in the cold season (increasing cell size) and elevated temperature at low nutrient concentrations in the warm season (decreasing cell size). Higher temperature in summer and lower salinity by increased land-runoff are expected to decrease the average cell size of primary producers, which is likely to affect the transfer of energy to higher trophic levels.

Effect of parental age and associated size on fecundity, growth and survival in the yellow seahorse Hippocampus kuda.

PubMed

Dzyuba, Borys; Van Look, Katrien J W; Cliffe, Alex; Koldewey, Heather J; Holt, William V

2006-08-01

Seahorses, together with the pipefishes (Family Syngnathidae), are the only vertebrates in which embryonic development takes place within a specialised body compartment, the brood pouch, of the male instead of the female. Embryos develop in close association with the brood pouch epithelium in a manner that bears some resemblance to embryo-placental relationships in mammals. We have explored the hypothesis that parental body size and age should affect offspring postnatal growth and survival if brood pouch quality impacts upon prenatal embryonic nutrition or respiration. Using an aquarium population of the yellow seahorse, Hippocampus kuda, we show here that large parents produce offspring whose initial postnatal growth rates (weeks one to three) were significantly higher than those of the offspring of younger and smaller parents. Whereas 90% of offspring from the larger parents survived for the duration of the study (7 weeks), less that 50% of offspring from smaller parents survived for the same period. For the offspring of large parents, growth rates from individual males were negatively correlated with the number of offspring in the cohort (r=-0.82; P<0.05); this was not the case for offspring from small parents (r=0.048; P>0.9). Observations of embryos within the pouch suggested that when relatively few embryos are present they may attach to functionally advantageous sites and thus gain physiological support during gestation. These results suggest that male body size, and pouch size and function, may influence the future fitness and survival of their offspring.

A Chinese alligator in heliox: formant frequencies in a crocodilian

PubMed Central

Reber, Stephan A.; Nishimura, Takeshi; Janisch, Judith; Robertson, Mark; Fitch, W. Tecumseh

2015-01-01

ABSTRACT Crocodilians are among the most vocal non-avian reptiles. Adults of both sexes produce loud vocalizations known as ‘bellows’ year round, with the highest rate during the mating season. Although the specific function of these vocalizations remains unclear, they may advertise the caller's body size, because relative size differences strongly affect courtship and territorial behaviour in crocodilians. In mammals and birds, a common mechanism for producing honest acoustic signals of body size is via formant frequencies (vocal tract resonances). To our knowledge, formants have to date never been documented in any non-avian reptile, and formants do not seem to play a role in the vocalizations of anurans. We tested for formants in crocodilian vocalizations by using playbacks to induce a female Chinese alligator (Alligator sinensis) to bellow in an airtight chamber. During vocalizations, the animal inhaled either normal air or a helium/oxygen mixture (heliox) in which the velocity of sound is increased. Although heliox allows normal respiration, it alters the formant distribution of the sound spectrum. An acoustic analysis of the calls showed that the source signal components remained constant under both conditions, but an upward shift of high-energy frequency bands was observed in heliox. We conclude that these frequency bands represent formants. We suggest that crocodilian vocalizations could thus provide an acoustic indication of body size via formants. Because birds and crocodilians share a common ancestor with all dinosaurs, a better understanding of their vocal production systems may also provide insight into the communication of extinct Archosaurians. PMID:26246611

Condition-dependent trade-offs between sexual traits, body condition and immunity: the effect of novel habitats.

PubMed

Iglesias-Carrasco, Maider; Head, Megan L; Jennions, Michael D; Cabido, Carlos

2016-06-21

The optimal allocation of resources to sexual signals and other life history traits is usually dependent on an individual's condition, while variation in the expression of sexual traits across environments depends on the combined effects of local adaptation, mean condition, and phenotypic responses to environment-specific cues that affect resource allocation. A clear contrast can often be drawn between natural habitats and novel habitats, such as forest plantations and urban areas. In some species, males seem to change their sexual signals in these novel environments, but why this occurs and how it affects signal reliability is still poorly understood. The relative size of sexual traits and level of immune responses were significantly lower for male palmate newts Lissotriton helveticus caught in pine and eucalyptus plantations compared to those caught in native forests, but there was no habitat-dependent difference in body condition (n = 18 sites, 382 males). The reliability with which sexual traits signalled body condition and immune responses was the same in all three habitats. Finally, we conducted a mesocosm experiment in which males were maintained in pine, eucalypt or oak infused water for 21 days. Males in plantation-like water (pine or eucalypt) showed significantly lower immune responses but no change in body condition. This matches the pattern seen for field-caught males. Unlike field-caught males, however, there was no relationship between water type and relative sexual trait size. Pine and eucalyptus plantations are likely to be detrimental to male palmate newt because they are associated with reduced immune function and smaller sexual traits. This could be because ecological aspects of these novel habitats, such as high water turbidity or changes in male-male competition, drive selection for reduced investment into sexual traits. However, it is more probable that there are differences in the ease of acquisition, hence optimal allocation, of resources among habitats. Our mesocosm experiment also provides some evidence that water toxicity is a causal factor. Our findings offer insights into how plantations affect amphibian life histories, and how novel habitats might generate long-term selection for new resource allocation strategies in native species.

Continuation of studies on thermoregulation of fish and turtles in thermally stressed habitats. Annual progress report, 1 October 1978-30 September 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spotila, J.R.

1979-06-01

A time dependent mathematical model accurately predicts heart, brain, and gut temperatures of largemouth bass. Body diameter, insulation thickness, and tissue thermal conductivity are controlling variables in the transfer of heat between a fish and water. Fish metabolic rate and water velocity across fish surfaces do not appreciably affect heat transfer rates. Multichannel temperature transmitters telemeter body temperatures of free swimming bass in Pond C on the Savannah River Plant while the behavior of those fish and other bass is recorded by an observer. Field studies of the home ranges and movements of turtles in Par Pond on the Savannahmore » River Plant are completed. We have recorded the movements of 30 individuals fitted with radio transmitters. Distinct differences are apparent in the behavior of turtles in areas affected by heated effluents as compared to those in control areas. Calculations and theoretical analysis of the transient energy exchange of turtles are continuing. Laboratory experiments using /sup 133/Xe indicate that blood flow in the muscles and skin of alligators increases 2 to 6 fold during movement. Relative variation is similar in magnitude to that seen in human muscle. Evaporative water loss from alligators decreases as body size increases. The ratios of respiratory to cutaneous water loss are 1.80 at 5/sup 0/C, 1.18 at 25/sup 0/C and 0.85 at 35/sup 0/C. Boundary layer resistances to evaporative water loss are 6 fold less than predicted by calculations of aerodynamic boundary layers. Body size is a primary factor in determining the thermoregulatory strategy that is to be used by a given animal.Operative environmental temperatures (T/sub e/) are as high as 60/sup 0/C for a turtle basking on a log in the sun. In a rainstorm T/sub e/ drops to 18/sup 0/C. Experiments to measure T/sub e/ for turtles in normal and thermally affected areas are now continuing on the Savannah River Plant. (ERB)« less

Overestimation of body size in eating disorders and its association to body-related avoidance behavior.

PubMed

Vossbeck-Elsebusch, Anna N; Waldorf, Manuel; Legenbauer, Tanja; Bauer, Anika; Cordes, Martin; Vocks, Silja

2015-06-01

Body-related avoidance behavior, e.g., not looking in the mirror, is a common feature of eating disorders. It is assumed that it leads to insufficient feedback concerning one's own real body form and might thus contribute to distorted mental representation of one's own body. However, this assumption still lacks empirical foundation. Therefore, the aim of the present study was to examine the relationship between misperception of one's own body and body-related avoidance behavior in N = 78 female patients with Bulimia nervosa and eating disorder not otherwise specified. Body-size misperception was assessed using a digital photo distortion technique based on an individual picture of each participant which was taken in a standardized suit. In a regression analysis with body-related avoidance behavior, body mass index and weight and shape concerns as predictors, only body-related avoidance behavior significantly contributed to the explanation of body-size overestimation. This result supports the theoretical assumption that body-related avoidance behavior makes body-size overestimation more likely.

Women's Preferences for Penis Size: A New Research Method Using Selection among 3D Models

PubMed Central

Park, Jaymie; Leung, Shannon

2015-01-01

Women’s preferences for penis size may affect men’s comfort with their own bodies and may have implications for sexual health. Studies of women’s penis size preferences typically have relied on their abstract ratings or selecting amongst 2D, flaccid images. This study used haptic stimuli to allow assessment of women’s size recall accuracy for the first time, as well as examine their preferences for erect penis sizes in different relationship contexts. Women (N = 75) selected amongst 33, 3D models. Women recalled model size accurately using this method, although they made more errors with respect to penis length than circumference. Women preferred a penis of slightly larger circumference and length for one-time (length = 6.4 inches/16.3 cm, circumference = 5.0 inches/12.7 cm) versus long-term (length = 6.3 inches/16.0 cm, circumference = 4.8 inches/12.2 cm) sexual partners. These first estimates of erect penis size preferences using 3D models suggest women accurately recall size and prefer penises only slightly larger than average. PMID:26332467

Women's Preferences for Penis Size: A New Research Method Using Selection among 3D Models.

PubMed

Prause, Nicole; Park, Jaymie; Leung, Shannon; Miller, Geoffrey

2015-01-01

Women's preferences for penis size may affect men's comfort with their own bodies and may have implications for sexual health. Studies of women's penis size preferences typically have relied on their abstract ratings or selecting amongst 2D, flaccid images. This study used haptic stimuli to allow assessment of women's size recall accuracy for the first time, as well as examine their preferences for erect penis sizes in different relationship contexts. Women (N = 75) selected amongst 33, 3D models. Women recalled model size accurately using this method, although they made more errors with respect to penis length than circumference. Women preferred a penis of slightly larger circumference and length for one-time (length = 6.4 inches/16.3 cm, circumference = 5.0 inches/12.7 cm) versus long-term (length = 6.3 inches/16.0 cm, circumference = 4.8 inches/12.2 cm) sexual partners. These first estimates of erect penis size preferences using 3D models suggest women accurately recall size and prefer penises only slightly larger than average.

Toxicity of Monoterpene Structure, Diversity and Concentration to Mountain Pine Beetles, Dendroctonus ponderosae: Beetle Traits Matter More.

PubMed

Reid, Mary L; Sekhon, Jagdeep K; LaFramboise, Lanielle M

2017-04-01

A high diversity of plant defenses may be a response to herbivore diversity or may be collectively more toxic than single compounds, either of which may be important for understanding insect-plant associations. Monoterpenes in conifers are particularly diverse. We tested the fumigant toxicity of four monoterpenes, alone and in combination, to mountain pine beetles, Dendroctonus ponderosae, in the context of the beetles' individual body traits. Chemical structures of tested monoterpene hydrocarbons had modest effects on beetle survival, mass loss, water content and fat content, with (R)-(+)-limonene tending to be more toxic than (-)-α-pinene, (-)-β-pinene, and (+)-3-carene. Monoterpene diversity (all qualitative combinations of one to four monoterpenes) did not affect toxicity. Concentration (0 to 1200 ppm) of individual monoterpenes was a strong determinant of toxicity. Beetle body size and body condition index strongly and positively affected survival during monoterpene treatments. Larger beetles in better condition lost proportionally less mass during exposure, where proportion mass loss negatively affected survivorship. Toxicity was much more associated with water loss than with fat loss, suggesting that a main cost of detoxification is excretion, a process that has received little attention. These results provide insight into the determinants of beetle success in historic and novel hosts that differ in monoterpene composition and concentration. We also suggest that water availability will affect beetle success directly through their ability to tolerate detoxification as well as indirectly through host responses to drought.

Life on the edge: carnivore body size variation is all over the place

PubMed Central

Meiri, Shai; Dayan, Tamar; Simberloff, Daniel; Grenyer, Richard

2009-01-01

Evolutionary biologists have long been fascinated by both the ways in which species respond to ecological conditions at the edges of their geographic ranges and the way that species' body sizes evolve across their ranges. Surprisingly, though, the relationship between these two phenomena is rarely studied. Here, we examine whether carnivore body size changes from the interior of their geographic range towards the range edges. We find that within species, body size often varies strongly with distance from the range edge. However, there is no general tendency across species for size to be either larger or smaller towards the edge. There is some evidence that the smallest guild members increase in size towards their range edges, but results for the largest guild members are equivocal. Whether individuals vary in relation to the distance from the range edges often depends on the way edge and interior are defined. Neither geographic range size nor absolute body size influences the tendency of size to vary with distance from the range edge. Therefore, we suggest that the frequent significant association between body size and the position of individuals along the edge-core continuum reflects the prevalence of geographic size variation and that the distance to range edge per se does not influence size evolution in a consistent way. PMID:19324818

Cell size is positively correlated between different tissues in passerine birds and amphibians, but not necessarily in mammals.

PubMed

Kozlowski, J; Czarnoleski, M; François-Krassowska, A; Maciak, S; Pis, T

2010-12-23

We examined cell size correlations between tissues, and cell size to body mass relationships in passerine birds, amphibians and mammals. The size correlated highly between all cell types in birds and amphibians; mammalian tissues clustered by size correlation in three tissue groups. Erythrocyte size correlated well with the volume of other cell types in birds and amphibians, but poorly in mammals. In birds, body mass correlated positively with the size of all cell types including erythrocytes, and in mammals only with the sizes of some cell types. Size of mammalian erythrocytes correlated with body mass only within the most taxonomically uniform group of species (rodents and lagomorphs). Cell volume increased with body mass of birds and mammals to less than 0.3 power, indicating that body size evolved mostly by changes in cell number. Our evidence suggests that epigenetic mechanisms determining cell size relationships in tissues are conservative in birds and amphibians, but less stringent in mammals. The patterns of cell size to body mass relationships we obtained challenge some key assumptions of fractal and cellular models used by allometric theory to explain mass-scaling of metabolism. We suggest that the assumptions in both models are not universal, and that such models need reformulation.

Multiple host-plant use may arise from gender-specific fitness effects

PubMed Central

Gibbs, Melanie; Lace, Lesley A.; Jones, Martin J.; Moore, Allen J.

2006-01-01

Ovipositing females are predicted to select host-plants that will maximise offspring survival and fitness. Yet hosts often differ in the component of larval fitness affected so host-selection often involves a trade-off between short development times and large size and high fecundity of offspring. If host-species can directly affect development rates and body size, and if there are gender differences in resource allocation during development, there can be different sex-specific selection pressures associated with different hosts. Using a Madeiran population of the speckled wood butterfly Pararge aegeria (L.) as the model species gender differences in larval development and size were examined in response to the hosts Brachypodium sylvaticum, Holcus lanatus and Poa annua. It was observed that male and female P. aegeria larvae differed, with their responses dependent on the host species. These results would suggest that oviposition behavior is a complex process, and use of multiple hosts may have evolved to balance the conflicting needs of male and female larvae. Co-evolution of host selection and oviposition behaviors may help to balance the differing performance needs of offspring. PMID:19537967

Influence of slice overlap on positron emission tomography image quality

NASA Astrophysics Data System (ADS)

McKeown, Clare; Gillen, Gerry; Dempsey, Mary Frances; Findlay, Caroline

2016-02-01

PET scans use overlapping acquisition beds to correct for reduced sensitivity at bed edges. The optimum overlap size for the General Electric (GE) Discovery 690 has not been established. This study assesses how image quality is affected by slice overlap. Efficacy of 23% overlaps (recommended by GE) and 49% overlaps (maximum possible overlap) were specifically assessed. European Association of Nuclear Medicine (EANM) guidelines for calculating minimum injected activities based on overlap size were also reviewed. A uniform flood phantom was used to assess noise (coefficient of variation, (COV)) and voxel accuracy (activity concentrations, Bq ml-1). A NEMA (National Electrical Manufacturers Association) body phantom with hot/cold spheres in a background activity was used to assess contrast recovery coefficients (CRCs) and signal to noise ratios (SNR). Different overlap sizes and sphere-to-background ratios were assessed. COVs for 49% and 23% overlaps were 9% and 13% respectively. This increased noise was difficult to visualise on the 23% overlap images. Mean voxel activity concentrations were not affected by overlap size. No clinically significant differences in CRCs were observed. However, visibility and SNR of small, low contrast spheres (⩽13 mm diameter, 2:1 sphere to background ratio) may be affected by overlap size in low count studies if they are located in the overlap area. There was minimal detectable influence on image quality in terms of noise, mean activity concentrations or mean CRCs when comparing 23% overlap with 49% overlap. Detectability of small, low contrast lesions may be affected in low count studies—however, this is a worst-case scenario. The marginal benefits of increasing overlap from 23% to 49% are likely to be offset by increased patient scan times. A 23% overlap is therefore appropriate for clinical use. An amendment to EANM guidelines for calculating injected activities is also proposed which better reflects the effect overlap size has on image noise.

Long-term and acute effects of temperature and oxygen on metabolism, food intake, growth and heat tolerance in a freshwater gastropod.

PubMed

Hoefnagel, K Natan; Verberk, Wilco C E P

2017-08-01

Temperature affects the physiology and life-history of ectothermic animals, often increasing metabolic rate and decreasing body size. Oxygen limitation has been put forward as a mechanism to explain thermal responses of body size and the ability to survive stress. However the time-scales involved in growth performance and heat tolerance differ radically. In order to increase our understanding of oxygen and temperature effects on body size and heat tolerance and the time scale involved, we reared Lymnaea stagnalis under six combinations of temperature and oxygen tension from hatching up to an age of 300 days and recorded shell length during this whole period. At the end of this period, we determined scope for growth by measuring food intake rate, assimilation efficiency, respiration rate and ammonium excretion rate at two different temperatures. We also measured the snails' ability to survive heat stress (CTmax), both at normoxia and hypoxia. We found that scope for growth and long term growth performance were much more affected by interactions of chronic oxygen and temperature conditions during rearing than by acute conditions during testing. Furthermore, our study shows that individual variation in growth performance can be traced back to individual differences in rates of food and oxygen consumption. Developmental acclimation also gave rise to differences in CTmax, but these were relatively small and were only expressed when CTmax was tested under hypoxia. The large effects of rearing oxygen conditions on growth and other physiological rates compared to modest effects of test oxygen conditions on CTmax suggest that small effects of hypoxia on the short term (e.g. heat tolerance) may nevertheless have large repercussions on the long term (e.g. growth and reproduction), even in a pulmonate snail that can compensate for hypoxia to some extent by aerial respiration. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Increased Dietary Supply of Medium-Chain Fatty Acids during Early Weaning in Rodents Prevents Excessive Fat Accumulation in Adulthood

PubMed Central

van de Heijning, Bert J. M.; Oosting, Annemarie; Kegler, Diane; van der Beek, Eline M.

2017-01-01

Medium-chain fatty acids (MCFA) are a directly and readily absorbed source of energy. Exposure early-in-life to increased MCFA levels might affect development and impact (lipid) metabolism later in life. We tested whether an increased MCFA intake early-in-life positively affects adult body composition and metabolic status when challenged by a western-style diet (WSD). Male offspring of C57Bl/6j mice and Wistar rats were fed a control diet (CTRL; 10 w% fat, 14% MCFA) or a medium-chain triglycerides (MCT) diet with 20% MCFA until postnatal (PN) day 42, whereupon animals were fed a WSD (10 w% fat) until PN day 98. Body composition was monitored by Dual Energy X-ray Absorptiometry (DEXA). In rats, glucose homeostasis was assessed by glucose tolerance test (GTT) and insulin tolerance test (ITT); in mice, the HOmeostasis Model Assessment of Insulin Resistance (HOMA-IR) was calculated. At autopsy on PN day 98, plasma lipid profiles, glucose, insulin, and adipokines were measured; organs and fat pads were collected and the adipocyte size distribution was analysed. Milk analysis in mice showed that the maternal MCT diet was not translated into milk, and pups were thus only exposed to high MCT levels from early weaning onward: PN day 16 until 42. Mice exposed to MCT showed 28% less fat accumulation vs. CTRL during WSD. The average adipocyte cell size, fasting plasma triglycerides (TG), and leptin levels were reduced in MCT mice. In rats, no effects were found on the adult body composition, but the adipocyte cell size distribution shifted towards smaller adipocytes. Particularly mice showed positive effects on glucose homeostasis and insulin sensitivity. Increased MCFA intake early-in-life protected against the detrimental effects of an obesogenic diet in adulthood. PMID:28632178

Influence of biological and physicochemical characteristics of larval habitats on the body size of Anopheles gambiae mosquitoes (Diptera: Culicidae) along the Kenyan coast

PubMed Central

Mwangangi, Joseph M.; Mbogo, Charles M.; Muturi, Ephantus J.; Nzovu, Joseph G.; Kabiru, Ephantus W.; Githure, John I.; Novak, Robert J.; Beier, John C.

2009-01-01

Background & objectives The number and productivity of larval habitats ultimately determine the density of adult mosquitoes. The biological and physicochemical conditions at the larval habitat affect larval development hence affecting the adult body size. The influence of biological and physicochemical characteristics on the body size of Anopheles gambiae was assessed in Jaribuni village, Kilifi district along the Kenyan Coast. Methods Ten cages measuring 1 × 1 × 1 m (1 m3) with a netting material were placed in 10 different aquatic habitats, which were positive for anopheline mosquito larvae. Emergent mosquitoes were collected daily by aspiration and the wing lengths were determined by microscopy. In the habitats, physicochemical parameters were assessed: pH, surface debris, algae and emergent plants, turbidity, substrate, nitrate, ammonia, phosphate and chlorophyll a content. Results A total of 685 anopheline and culicine mosquitoes were collected from the emergent cages. Only female mosquitoes were considered in this study. Among the Anopheles spp, 202 were An. gambiae s.s., eight An. arabiensis, two An. funestus, whereas the Culex spp was composed of 214 Cx. quinquefasciatus, 10 Cx. tigripes, eight Cx. annulioris and one Cx. cumminsii. The mean wing length of the female An. gambiae s.s. mosquitoes was 3.02 mm (n = 157), while that of An. arabiensis was 3.09 mm (n = 9). There were no associations between the wing lengths and the environmental and chemical parameters, except for a positive correlation between wing length of An. gambiae and chlorophyll a content (r = 0.622). The day on which the mosquitoes emerged was not significant for the anopheline (p = 0.324) or culicine mosquitoes (p = 0.374), because the mosquito emerged from the cages on a daily basis. Interpretation & conclusion In conclusion, there was variability in production of emergent mosquitoes from different habitats, which means that there should be targeted control on these habitats based on productivity. PMID:17722866

Influence of biological and physicochemical characteristics of larval habitats on the body size of Anopheles gambiae mosquitoes (Diptera: Culicidae) along the Kenyan coast.

PubMed

Mwangangi, Joseph M; Mbogo, Charles M; Muturi, Ephantus J; Nzovua, Joseph G; Kabiru, Ephantus W; Githure, John I; Novak, Robert J; Beier, John C

2007-06-01

The number and productivity of larval habitats ultimately determine the density of adult mosquitoes. The biological and physicochemical conditions at the larval habitat affect larval development hence affecting the adult body size. The influence of biological and physicochemical characteristics on the body size of Anopheles gambiae was assessed in Jaribuni village, Kilifi district along the Kenyan Coast. Ten cages measuring 1 x 1 x 1 m (1 m3) with a netting material were placed in 10 different aquatic habitats, which were positive for anopheline mosquito larvae. Emergent mosquitoes were collected daily by aspiration and the wing lengths were determined by microscopy. In the habitats, physicochemical parameters were assessed: pH, surface debris, algae and emergent plants, turbidity, substrate, nitrate, ammonia, phosphate and chlorophyll a content. A total of 685 anopheline and culicine mosquitoes were collected from the emergent cages. Only female mosquitoes were considered in this study. Among the Anopheles spp, 202 were An. gambiae s.s., eight An. arabiensis, two An. funestus, whereas the Culex spp was composed of 214 Cx. quinquefasciatus, 10 Cx. tigripes, eight Cx. annulioris and one Cx. cumminsii. The mean wing length of the female An. gambiae s.s. mosquitoes was 3.02 mm (n=157), while that of An. arabiensis was 3.09 mm (n=9). There were no associations between the wing lengths and the environmental and chemical parameters, except for a positive correlation between wing length of An. gambiae and chlorophyll a content (r = 0.622). The day on which the mosquitoes emerged was not significant for the anopheline (p = 0.324) or culicine mosquitoes (p = 0.374), because the mosquito emerged from the cages on a daily basis. In conclusion, there was variability in production of emergent mosquitoes from different habitats, which means that there should be targeted control on these habitats based on productivity.

Ethnic differences in the effects of media on body image: the effects of priming with ethnically different or similar models.

PubMed

Bruns, Gina L; Carter, Michele M

2015-04-01

Media exposure has been positively correlated with body dissatisfaction. While body image concerns are common, being African American has been found to be a protective factor in the development of body dissatisfaction. Participants either viewed ten advertisements showing 1) ethnically-similar thin models; 2) ethnically-different thin models; 3) ethnically-similar plus-sized models; and 4) ethnically-diverse plus-sized models. Following exposure, body image was measured. African American women had less body dissatisfaction than Caucasian women. Ethnically-similar thin-model conditions did not elicit greater body dissatisfaction scores than ethnically-different thin or plus-sized models nor did the ethnicity of the model impact ratings of body dissatisfaction for women of either race. There were no differences among the African American women exposed to plus-sized versus thin models. Among Caucasian women exposure to plus-sized models resulted in greater body dissatisfaction than exposure to thin models. Results support existing literature that African American women experience less body dissatisfaction than Caucasian women even following exposure to an ethnically-similar thin model. Additionally, women exposed to plus-sized model conditions experienced greater body dissatisfaction than those shown thin models. Copyright © 2014 Elsevier Ltd. All rights reserved.

Exploring the Genetic Signature of Body Size in Yucatan Miniature Pig

PubMed Central

Kim, Hyeongmin; Song, Ki Duk; Kim, Hyeon Jeong; Park, WonCheoul; Kim, Jaemin; Lee, Taeheon; Shin, Dong-Hyun; Kwak, Woori; Kwon, Young-jun; Sung, Samsun; Moon, Sunjin; Lee, Kyung-Tai; Kim, Namshin; Hong, Joon Ki; Eo, Kyung Yeon; Seo, Kang Seok; Kim, Girak; Park, Sungmoo; Yun, Cheol-Heui; Kim, Hyunil; Choi, Kimyung; Kim, Jiho; Lee, Woon Kyu; Kim, Duk-Kyung; Oh, Jae-Don; Kim, Eui-Soo; Cho, Seoae; Lee, Hak-Kyo; Kim, Tae-Hun; Kim, Heebal

2015-01-01

Since being domesticated about 10,000–12,000 years ago, domestic pigs (Sus scrofa domesticus) have been selected for traits of economic importance, in particular large body size. However, Yucatan miniature pigs have been selected for small body size to withstand high temperature environment and for laboratory use. This renders the Yucatan miniature pig a valuable model for understanding the evolution of body size. We investigate the genetic signature for selection of body size in the Yucatan miniature pig. Phylogenetic distance of Yucatan miniature pig was compared to other large swine breeds (Yorkshire, Landrace, Duroc and wild boar). By estimating the XP-EHH statistic using re-sequencing data derived from 70 pigs, we were able to unravel the signatures of selection of body size. We found that both selections at the level of organism, and at the cellular level have occurred. Selection at the higher levels include feed intake, regulation of body weight and increase in mass while selection at the molecular level includes cell cycle and cell proliferation. Positively selected genes probed by XP-EHH may provide insight into the docile character and innate immunity as well as body size of Yucatan miniature pig. PMID:25885114

Factors determining the average body size of geographically separated Arctodiaptomus salinus (Daday, 1885) populations

PubMed Central

Anufriieva, Elena V.; Shadrin, Nickolai V.

2014-01-01

Arctodiaptomus salinus inhabits water bodies across Eurasia and North Africa. Based on our own data and that from the literature, we analyzed the influences of several factors on the intra- and inter-population variability of this species. A strong negative linear correlation between temperature and average body size in the Crimean and African populations was found, in which the parameters might be influenced by salinity. Meanwhile, asignificant negative correlation between female body size and the altitude of habitats was found by comparing body size in populations from different regions. Individuals from environments with highly varying abiotic parameters, e.g. temporary reservoirs, had a larger body size than individuals from permanent water bodies. The changes in average body mass in populations were at 11.4 times, whereas, those in individual metabolic activities were at 6.2 times. Moreover, two size groups of A. salinus in the Crimean and the Siberian lakes were observed. The ratio of female length to male length fluctuatedbetween 1.02 and 1.30. The average size of A. salinus in populations and its variations were determined by both genetic and environmental factors. However, the paritiesof these factors were unequal in either spatial or temporal scales. PMID:24668656

Factors determining the average body size of geographically separated Arctodiaptomus salinus (Daday, 1885) populations.

PubMed

Anufriieva, Elena V; Shadrin, Nickolai V

2014-03-01

Arctodiaptomus salinus inhabits water bodies across Eurasia and North Africa. Based on our own data and that from the literature, we analyzed the influences of several factors on the intra- and inter-population variability of this species. A strong negative linear correlation between temperature and average body size in the Crimean and African populations was found, in which the parameters might be influenced by salinity. Meanwhile, a significant negative correlation between female body size and the altitude of habitats was found by comparing body size in populations from different regions. Individuals from environments with highly varying abiotic parameters, e.g. temporary reservoirs, had a larger body size than individuals from permanent water bodies. The changes in average body mass in populations were at 11.4 times, whereas, those in individual metabolic activities were at 6.2 times. Moreover, two size groups of A. salinus in the Crimean and the Siberian lakes were observed. The ratio of female length to male length fluctuated between 1.02 and 1.30. The average size of A. salinus in populations and its variations were determined by both genetic and environmental factors. However, the parities of these factors were unequal in either spatial or temporal scales.