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Sample records for affect body size

  1. Sneaker Males Affect Fighter Male Body Size and Sexual Size Dimorphism in Salmon.

    PubMed

    Weir, Laura K; Kindsvater, Holly K; Young, Kyle A; Reynolds, John D

    2016-08-01

    Large male body size is typically favored by directional sexual selection through competition for mates. However, alternative male life-history phenotypes, such as "sneakers," should decrease the strength of sexual selection acting on body size of large "fighter" males. We tested this prediction with salmon species; in southern populations, where sneakers are common, fighter males should be smaller than in northern populations, where sneakers are rare, leading to geographical clines in sexual size dimorphism (SSD). Consistent with our prediction, fighter male body size and SSD (fighter male∶female size) increase with latitude in species with sneaker males (Atlantic salmon Salmo salar and masu salmon Oncorhynchus masou) but not in species without sneakers (chum salmon Oncorhynchus keta and pink salmon Oncorhynchus gorbuscha). This is the first evidence that sneaker males affect SSD across populations and species, and it suggests that alternative male mating strategies may shape the evolution of body size.

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

    USGS Publications Warehouse

    Winter, M.; Johnson, D.H.; Shaffer, J.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. ?? The Cooper Ornithological Society 2006.

  3. Body size affects the evolution of eyespots in caterpillars

    PubMed Central

    Skelhorn, John; Breinholt, Jesse W.; Kawahara, Akito Y.; Sherratt, Thomas N.

    2015-01-01

    Many caterpillars have conspicuous eye-like markings, called eyespots. Despite recent work demonstrating the efficacy of eyespots in deterring predator attack, a fundamental question remains: Given their protective benefits, why have eyespots not evolved in more caterpillars? Using a phylogenetically controlled analysis of hawkmoth caterpillars, we show that eyespots are associated with large body size. This relationship could arise because (i) large prey are innately conspicuous; (ii) large prey are more profitable, and thus face stronger selection to evolve such defenses; and/or (iii) eyespots are more effective on large-bodied prey. To evaluate these hypotheses, we exposed small and large caterpillar models with and without eyespots in a 2 × 2 factorial design to avian predators in the field. Overall, eyespots increased prey mortality, but the effect was particularly marked in small prey, and eyespots decreased mortality of large prey in some microhabitats. We then exposed artificial prey to naïve domestic chicks in a laboratory setting following a 2 × 3 design (small or large size × no, small, or large eyespots). Predators attacked small prey with eyespots more quickly, but were more wary of large caterpillars with large eyespots than those without eyespots or with small eyespots. Taken together, these data suggest that eyespots are effective deterrents only when both prey and eyespots are large, and that innate aversion toward eyespots is conditional. We conclude that the distribution of eyespots in nature likely results from selection against eyespots in small caterpillars and selection for eyespots in large caterpillars (at least in some microhabitats). PMID:25964333

  4. Body size affects the evolution of eyespots in caterpillars.

    PubMed

    Hossie, Thomas John; Skelhorn, John; Breinholt, Jesse W; Kawahara, Akito Y; Sherratt, Thomas N

    2015-05-26

    Many caterpillars have conspicuous eye-like markings, called eyespots. Despite recent work demonstrating the efficacy of eyespots in deterring predator attack, a fundamental question remains: Given their protective benefits, why have eyespots not evolved in more caterpillars? Using a phylogenetically controlled analysis of hawkmoth caterpillars, we show that eyespots are associated with large body size. This relationship could arise because (i) large prey are innately conspicuous; (ii) large prey are more profitable, and thus face stronger selection to evolve such defenses; and/or (iii) eyespots are more effective on large-bodied prey. To evaluate these hypotheses, we exposed small and large caterpillar models with and without eyespots in a 2 × 2 factorial design to avian predators in the field. Overall, eyespots increased prey mortality, but the effect was particularly marked in small prey, and eyespots decreased mortality of large prey in some microhabitats. We then exposed artificial prey to naïve domestic chicks in a laboratory setting following a 2 × 3 design (small or large size × no, small, or large eyespots). Predators attacked small prey with eyespots more quickly, but were more wary of large caterpillars with large eyespots than those without eyespots or with small eyespots. Taken together, these data suggest that eyespots are effective deterrents only when both prey and eyespots are large, and that innate aversion toward eyespots is conditional. We conclude that the distribution of eyespots in nature likely results from selection against eyespots in small caterpillars and selection for eyespots in large caterpillars (at least in some microhabitats).

  5. A delay in pubertal onset affects the covariation of body weight, estradiol, and bone size.

    PubMed

    Yingling, Vanessa R

    2009-04-01

    The skeletal system functions as a locomotive organ and a mineral reservoir and combinations of genetic and environmental factors affect the skeletal system. Although delayed puberty is associated with compromised bone mass, suppression of estrogen should be beneficial to cortical strength. The purpose was to employ path analysis to study bone strength and delayed puberty. Forty-five female rats were randomly assigned to a control group (n = 15) and an experimental group (n = 30) that received injections of gonadotropin releasing hormone antagonist (GnRH-a). Causal models were constructed by specifying directed paths between bone traits. The first model tested the hypothesis that the functional relationships between bone traits and body weight were altered by a delay in pubertal onset. GnRH-a injections during puberty altered the covariation between body weight and bone size. The second model was constructed to test the hypothesis that variability in stiffness was causally related to variability in body weight. The model also tested the relationship between the periosteal and endocortical surfaces and their relationship to stiffness. There was no change in the relationship between the surfaces in the GnRH-a group. The third model determined the effect of estradiol on both total area and relative cortical area in both groups. The relationship between periosteal surface and serum estradiol levels was only significant during estrogen suppression. These data suggest that increases in body weight during or prior to puberty may not be protective of bone strength.

  6. Body size, but not cooling rate, affects supercooling points in the red imported fire ant, Solenopsis invicta.

    PubMed

    Hahn, Daniel A; Martin, Adam R; Porter, Sanford D

    2008-10-01

    The level of an animal's stress resistance is set by multiple intrinsic physiological and extrinsic environmental parameters. Body size is a critical intrinsic parameter that affects numerous fitness-related organismal traits including fecundity, survival, mating success, and stress resistance. The rate of cooling is a critical extrinsic environmental factor that can affect thermal stress resistance. Workers of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), display considerable variation in adult body size. Therefore, developing ecologically realistic models of thermotolerance in this species requires a consideration of body size. We tested the hypothesis that body size and cooling rate would interact to set the supercooling point in fire ant workers by exposing workers of a range of body sizes to three different cooling regimens: a very fast ramp of -10 degrees C/min, an intermediate ramp of -1 degrees C/min, and an ecologically relevant slow ramp of -0.1 degrees C/min. Specifically, we asked whether large workers were more susceptible to differences in cooling rate than smaller workers. We found that body size had a considerable effect on supercooling point with the largest workers freezing at a temperature approximately 3 degrees C higher than the smallest workers. Cooling rate had a very small effect on supercooling point, and there was no interaction between the two factors. Therefore, the allometry of supercooling points across the range of worker body sizes does not change with cooling rate.

  7. 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.

  8. Nectar foraging behaviour is affected by ant body size in Camponotus mus.

    PubMed

    Medan, Violeta; Josens, Roxana B

    2005-08-01

    The nectivorous ant Camponotus mus shows a broad size variation within the worker caste. Large ants can ingest faster and larger loads than small ones. Differences in physiological abilities in fluid ingestion due to the insect size could be related to differences in decision-making according to ant size during nectar foraging. Sucrose solutions of different levels of sugar concentration (30% or 60%w/w), viscosity (high or low) or flow rate (ad libitum or 1microl/min) were offered in combination to analyse the behavioural responses to each of these properties separately. Differences were found depending on ant body size and the property compared. A regulated flow produced smaller crop loads for medium and large ants compared to the same solution given ad libitum. All foragers remained longer times feeding at the regulated flow source but larger ants often made longer interruptions. When sugar concentration was constant but viscosity was high, only large ants increased feeding time. Constant viscosity with different sugar concentration determined longer feeding time and bigger loads for the most concentrated solution for small but not for large ants. Small ants reached similar crop loads in a variety of conditions while large ants did not. These differences could be evidence of a possible specialization for nectar foraging based on ant body size.

  9. Body size affects individual winter foraging strategies of thick-billed murres in the Bering Sea.

    PubMed

    Orben, Rachael A; Paredes, Rosana; Roby, Daniel D; Irons, David B; Shaffer, Scott A

    2015-11-01

    Foraging and migration often require different energetic and movement strategies. Though not readily apparent, constraints during one phase might influence the foraging strategies observed in another. For marine birds that fly and dive, body size constraints likely present a trade-off between foraging ability and migration as smaller bodies reduce flight costs, whereas larger bodies are advantageous for diving deeper. This study examines individual wintering strategies of deep diving thick-billed murres (Uria lomvia) breeding at three colonies in the south-eastern Bering Sea: St Paul, St George and Bogoslof. These colonies, arranged north to south, are located such that breeding birds forage in a gradient from shelf to deep-water habitats. We used geolocation time-depth recorders and stable isotopes from feathers to determine differences in foraging behaviour and diet of murres during three non-breeding periods, 2008-2011. Body size was quantified by a principal component analysis (wing, culmen, head+bill and tarsus length). A hierarchical cluster analysis identified winter foraging strategies based on individual movement, diving behaviour and diet (inferred from stable isotopes). Structural body size differed by breeding island. Larger birds from St Paul had higher wing loading than smaller birds from St George. Larger birds, mainly from St Paul, dove to deeper depths, spent more time in the Bering Sea, and likely consumed higher trophic-level prey in late winter. Three winter foraging strategies were identified. The main strategy, employed by small birds from all three breeding colonies in the first 2 years, was characterized by high residency areas in the North Pacific south of the Aleutians and nocturnal diving. In contrast, 31% of birds from St Paul remained in the Bering Sea and foraged mainly during the day, apparently feeding on higher trophic-level prey. Throat feather stable isotopes indicated that individuals exhibited flexibility in the use of this

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

    PubMed Central

    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. PMID:26047491

  11. Body size, but not cooling rate affects supercooling points in the red imported fire ant Solenopsis invicta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The level of an animal’s stress resistance is set by multiple intrinsic physiological and extrinsic environmental parameters. Body size is a critical intrinsic parameter that affects numerous fitness-related organismal traits including fecundity, survival, mating success, and stress resistance. The ...

  12. How body size affects middle-ear structure and function and auditory sensitivity in gekkonoid lizards.

    PubMed

    Werner, Y L; Montgomery, L G; Safford, S D; Igic, P G; Saunders, J C

    1998-02-01

    Gekkonoid lizards increase in body size throughout life, and the present study investigates whether changes in auditory function accompany these increases. Middle-ear structures in four groups of animals, adults and juveniles of two gekkonoid species (Eublepharis macularius and Oedura marmorata), were examined. Tympanic membrane velocity and phase were also measured in all four groups. An indication of peripheral auditory function was obtained for each group by measuring compound action potentials (CAPs) from the round window membrane. The middle-ear contribution to CAP thresholds was obtained by comparing threshold levels of the CAP response with and without an intact middle-ear system. The results from these studies indicated that significant changes occurred in middle-ear structure, tympanic membrane velocity and CAP threshold between the younger and older animals. In addition, the adults of both species exhibited better auditory function when the acoustic stimulus was delivered to the tympanic membrane than when it was delivered to the columella footplate. The findings show clearly that increased body size (or age) is accompanied by functional changes in the auditory periphery.

  13. Activity affects intraspecific body-size scaling of metabolic rate in ectothermic animals.

    PubMed

    Glazier, Douglas Stewart

    2009-10-01

    Metabolic rate is commonly thought to scale with body mass (M) to the 3/4 power. However, the metabolic scaling exponent (b) may vary with activity state, as has been shown chiefly for interspecific relationships. Here I use a meta-analysis of literature data to test whether b changes with activity level within species of ectothermic animals. Data for 19 species show that b is usually higher during active exercise (mean +/- 95% confidence limits = 0.918 +/- 0.038) than during rest (0.768 +/- 0.069). This significant upward shift in b to near 1 is consistent with the metabolic level boundaries hypothesis, which predicts that maximal metabolic rate during exercise should be chiefly influenced by volume-related muscular power production (scaling as M (1)). This dependence of b on activity level does not appear to be a simple temperature effect because body temperature in ectotherms changes very little during exercise.

  14. Mating status and body size in Aedes albopictus (Diptera: Culicidae) affect host finding and DEET repellency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variations in the conditions accompanying mosquito development and mating can result in females of variable size that have not been inseminated. In this study, we compared the host finding activity of mated and unmated large and small Aedes albopictus and the repellency to these mosquitoes of 25% D...

  15. 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.

  16. Cognitive Processing about Classroom-Relevant Contexts: Teachers' Attention to and Utilization of Girls' Body Size, Ethnicity, Attractiveness, and Facial Affect

    ERIC Educational Resources Information Center

    Wang, Shirley S.; Treat, Teresa A.; Brownell, Kelly D.

    2008-01-01

    This study examines 2 aspects of cognitive processing in person perception--attention and decision making--in classroom-relevant contexts. Teachers completed 2 implicit, performance-based tasks that characterized attention to and utilization of 4 student characteristics of interest: ethnicity, facial affect, body size, and attractiveness. Stimuli…

  17. Dopamine regulates body size in Caenorhabditis elegans.

    PubMed

    Nagashima, Takashi; Oami, Eitaro; Kutsuna, Natsumaro; Ishiura, Shoichi; Suo, Satoshi

    2016-04-01

    The nervous system plays a critical role in the regulation of animal body sizes. In Caenorhabditis elegans, an amine neurotransmitter, dopamine, is required for the tactile perception of food and food-dependent behavioral changes, while its role in development is unknown. In this study, we show that dopamine negatively regulates body size through a D2-like dopamine receptor, DOP-3, in C. elegans. Dopamine alters body size without affecting food intake or developmental rate. We also found that dopamine promotes egg-laying, although the regulation of body size by dopamine was not solely caused by this effect. Furthermore, dopamine negatively regulates body size through the suppression of signaling by octopamine and Gq-coupled octopamine receptors, SER-3 and SER-6. Our results demonstrate that dopamine and octopamine regulate the body size of C. elegans and suggest a potential role for perception in addition to ingestion of food for growth.

  18. A prospective study of calf factors affecting age, body size, and body condition score at first calving of holstein dairy heifers.

    PubMed

    Heinrichs, A J; Heinrichs, B S; Harel, O; Rogers, G W; Place, N T

    2005-08-01

    Data were collected prospectively on parameters related to first calving on 18 farms located in Northeastern Pennsylvania. This project was designed to study possible residual effects of calf management practices and events occurring during the first 16 wk of life on age, BW, skeletal growth, and body condition score at first calving. Multiple imputation method for handling missing data was incorporated in these analyses. This method has the advantage over ad hoc single imputations because the appropriate error structure is maintained. Much similarity was found between the multiple imputation method and a traditional mixed model analysis, except that some estimates from the multiple imputation method seemed more logical in their effects on the parameter measured. Factors related to increased age at first calving were increased difficulty of delivery, antibiotic treatment of sick calves, increased amount of milk or milk replacer fed before weaning, reduced quality of forage fed to weaned calves, maximum humidity, mean daily temperature, and maximum ammonia levels in calf housing areas. Body weight at calving tended to increase with parity of the dam, increased amount of grain fed to calves, increased ammonia levels, and increased mean temperature of the calf housing area. Body condition score at calving tended to be positively influenced by delivery score at first calving, dam parity, and milk or milk replacer dry matter intake. Withers height at calving was positively affected by treatment of animals with antibiotics and increased mean temperature in the calf area. This study demonstrated that nutrition, housing, and management factors that affect health and growth of calves have long-term effects on the animal at least through first calving.

  19. Body Size in Mammalian Paleobiology

    NASA Astrophysics Data System (ADS)

    Damuth, John; MacFadden, Bruce J.

    1990-11-01

    This valuable collection of essays presents and evaluates techniques of body-mass estimation and reviews current and potential applications of body-size estimates in paleobiology. Papers discuss explicitly the errors and biases of various regression techniques and predictor variables, and the identification of functionally similar groups of species for improving the accuracy of estimates. At the same time other chapters review and discuss the physiological, ecological, and behavioral correlates of body size in extant mammals; the significance of body-mass distributions in mammalian faunas; and the ecology and evolution of body size in particular paleofaunas. Coverage is particularly detailed for carnivores, primates, and ungulates, but information is also presented on marsupials, rodents, and proboscideans.

  20. How Body Affects Brain.

    PubMed

    Suzuki, Wendy A

    2016-08-09

    Studies show that physical exercise can affect a range of brain and cognitive functions. However, little is known about the peripheral signals that initiate these central changes. Moon et al. (2016) provide exciting new evidence that a novel myokine, cathepsin B (CTSB), released with exercise is associated with improved memory.

  1. Variability in human body size

    NASA Technical Reports Server (NTRS)

    Annis, J. F.

    1978-01-01

    The range of variability found among homogeneous groups is described and illustrated. Those trends that show significantly marked differences between sexes and among a number of racial/ethnic groups are also presented. Causes of human-body size variability discussed include genetic endowment, aging, nutrition, protective garments, and occupation. The information is presented to aid design engineers of space flight hardware and equipment.

  2. 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.

  3. Gender Affects Body Language Reading

    PubMed Central

    Sokolov, Arseny A.; Krüger, Samuel; Enck, Paul; Krägeloh-Mann, Ingeborg; Pavlova, Marina A.

    2011-01-01

    Body motion is a rich source of information for social cognition. However, gender effects in body language reading are largely unknown. Here we investigated whether, and, if so, how recognition of emotional expressions revealed by body motion is gender dependent. To this end, females and males were presented with point-light displays portraying knocking at a door performed with different emotional expressions. The findings show that gender affects accuracy rather than speed of body language reading. This effect, however, is modulated by emotional content of actions: males surpass in recognition accuracy of happy actions, whereas females tend to excel in recognition of hostile angry knocking. Advantage of women in recognition accuracy of neutral actions suggests that females are better tuned to the lack of emotional content in body actions. The study provides novel insights into understanding of gender effects in body language reading, and helps to shed light on gender vulnerability to neuropsychiatric and neurodevelopmental impairments in visual social cognition. PMID:21713180

  4. 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.

  5. Body size and chronic acceleration

    NASA Technical Reports Server (NTRS)

    Pitts, G. C.

    1976-01-01

    Experiments were conducted to study body composition as a function of acceleration (1-4.7 G) in mice and rats. It is shown that fat-free body mass is a predictable function of acceleration, and that of nine components of the fat-free body mass only skeletal muscle, liver and heart contributed to observed changes induced by delta G. Fat-free body mass was found to pass through a maximum at 1 G when it was plotted vs G for mice, rats and monkeys (1-4.7 G) and men (0-1 G).

  6. 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.

  7. 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.

  8. 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.

  9. Cell size versus body size in geophilomorph centipedes

    NASA Astrophysics Data System (ADS)

    Moretto, Marco; Minelli, Alessandro; Fusco, Giuseppe

    2015-04-01

    Variation in animal body size is the result of a complex interplay between variation in cell number and cell size, but the latter has seldom been considered in wide-ranging comparative studies, although distinct patterns of variation have been described in the evolution of different lineages. We investigated the correlation between epidermal cell size and body size in a sample of 29 geophilomorph centipede species, representative of a wide range of body sizes, from 6 mm dwarf species to gigantic species more than 200 mm long, exploiting the marks of epidermal cells on the overlying cuticle in the form of micro-sculptures called scutes. We found conspicuous and significant variation in average scute area, both between suprageneric taxa and between genera, while the within-species range of variation is comparatively small. This supports the view that the average epidermal cell size is to some extent taxon specific. However, regression analyses show that neither body size nor the number of leg-bearing segments explain this variation, which suggests that cell size is not an usual target of change for body size evolution in this group of arthropods, although there is evidence of its correlation with other morphological variables, like cuticle thickness. Scute sizes of miniaturized geophilomorph species are well within the range of the lineage to which the species belong, suggesting recent evolutionary transitions to smaller body size.

  10. Body size evolution in Mesozoic birds.

    PubMed

    Hone, D W E; Dyke, G J; Haden, M; Benton, M J

    2008-03-01

    The tendency for the mean body size of taxa within a clade to increase through evolution (Cope's Rule) has been demonstrated in a number of terrestrial vertebrate groups. However, because avian body size is strongly constrained by flight, any increase in size during the evolution of this lineage should be limited - there is a maximum size that can be attained by a bird for it to be able to get off the ground. Contrary to previous interpretations of early avian evolution, we demonstrate an overall increase in body size across Jurassic and Cretaceous flying birds: taxon body size increases from the earliest Jurassic through to the end of the Cretaceous, across a time span of 70 Myr. Although evidence is limited that this change is directional, it is certainly nonrandom. Relative size increase occurred presumably as the result of an increase in variance as the avian clade diversified after the origin of flight: a progression towards larger body size is seen clearly within the clades Pygostylia and Ornithothoraces. In contrast, a decrease in body size characterizes the most crownward lineage Ornithuromorpha, the clade that includes all extant taxa, and potentially may explain the survival of these birds across the Cretaceous-Palaeogene boundary. As in all other dinosaurs, counter selection for small size is seen in some clades, whereas body size is increasing overall.

  11. Studying the Body Sizes of Echinoidea during the Mesozoic Era

    NASA Astrophysics Data System (ADS)

    Tenorio, E.; Gupta, A.; Panneerselvam, S.; Heim, N. A.; Payne, J.

    2013-12-01

    Body size is an important trait that is affected by many factors such as temperature and space, more specifically the distance from the equator. We are studying whether Bergmann's rule or Cope's rule is dominant in the class Echinoidea during the Mesozoic Era. Bergmann's rule states that temperature and body size have an inverse correlation: as temperature decreases, body size increases. Bergmann's rule also states that as the distance from the equator increases, body size increases. The other principle we are studying, Cope's rule, dictates that the overall body size of an organism increases over time. Because CO2 is a greenhouse gas, we used rCO2 as a proxy for paleotemperature. The result from plotting body size against time was that as time progressed, body size tended to increase, supporting Cope's rule. By conducting correlation tests, we found that rCO2 and maximum area had a small, but significant, negative correlation, proving Bergmann's rule, but showing that there are other significant factors affecting the body sizes of Echinoids during this time period. After plotting the sizes against space, we found that these two factors had an inverse correlation during the Jurassic and Cretaceous periods, indicating that as distance from equator increases, size decreases. Cope's rule was supported since the overall trend is an increase in Echinoidea body size; in terms of space, however, Bergmann's rule did not apply to the class Echinoidea because the overall body size of the echinoderm decreased as the distance from equator increased. With this unexpected result, we concluded that there must have been another driving force other than temperature that influenced echinoids during the Mesozoic Era.

  12. 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…

  13. Temperature alters food web body-size structure.

    PubMed

    Gibert, Jean P; DeLong, John P

    2014-08-01

    The increased temperature associated with climate change may have important effects on body size and predator-prey interactions. The consequences of these effects for food web structure are unclear because the relationships between temperature and aspects of food web structure such as predator-prey body-size relationships are unknown. Here, we use the largest reported dataset for marine predator-prey interactions to assess how temperature affects predator-prey body-size relationships among different habitats ranging from the tropics to the poles. We found that prey size selection depends on predator body size, temperature and the interaction between the two. Our results indicate that (i) predator-prey body-size ratios decrease with predator size at below-average temperatures and increase with predator size at above-average temperatures, and (ii) that the effect of temperature on predator-prey body-size structure will be stronger at small and large body sizes and relatively weak at intermediate sizes. This systematic interaction may help to simplify forecasting the potentially complex consequences of warming on interaction strengths and food web stability.

  14. Body size distribution of the dinosaurs.

    PubMed

    O'Gorman, Eoin J; Hone, David W E

    2012-01-01

    The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size.

  15. Body Size Distribution of the Dinosaurs

    PubMed Central

    O’Gorman, Eoin J.; Hone, David W. E.

    2012-01-01

    The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size. PMID:23284818

  16. 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

  17. Being Barbie: the size of one's own body determines the perceived size of the world.

    PubMed

    van der Hoort, Björn; Guterstam, Arvid; Ehrsson, H Henrik

    2011-01-01

    A classical question in philosophy and psychology is if the sense of one's body influences how one visually perceives the world. Several theoreticians have suggested that our own body serves as a fundamental reference in visual perception of sizes and distances, although compelling experimental evidence for this hypothesis is lacking. In contrast, modern textbooks typically explain the perception of object size and distance by the combination of information from different visual cues. Here, we describe full body illusions in which subjects experience the ownership of a doll's body (80 cm or 30 cm) and a giant's body (400 cm) and use these as tools to demonstrate that the size of one's sensed own body directly influences the perception of object size and distance. These effects were quantified in ten separate experiments with complementary verbal, questionnaire, manual, walking, and physiological measures. When participants experienced the tiny body as their own, they perceived objects to be larger and farther away, and when they experienced the large-body illusion, they perceived objects to be smaller and nearer. Importantly, despite identical retinal input, this "body size effect" was greater when the participants experienced a sense of ownership of the artificial bodies compared to a control condition in which ownership was disrupted. These findings are fundamentally important as they suggest a causal relationship between the representations of body space and external space. Thus, our own body size affects how we perceive the world.

  18. Sauropod dinosaurs evolved moderately sized genomes unrelated to body size.

    PubMed

    Organ, Chris L; Brusatte, Stephen L; Stein, Koen

    2009-12-22

    Sauropodomorph dinosaurs include the largest land animals to have ever lived, some reaching up to 10 times the mass of an African elephant. Despite their status defining the upper range for body size in land animals, it remains unknown whether sauropodomorphs evolved larger-sized genomes than non-avian theropods, their sister taxon, or whether a relationship exists between genome size and body size in dinosaurs, two questions critical for understanding broad patterns of genome evolution in dinosaurs. Here we report inferences of genome size for 10 sauropodomorph taxa. The estimates are derived from a Bayesian phylogenetic generalized least squares approach that generates posterior distributions of regression models relating genome size to osteocyte lacunae volume in extant tetrapods. We estimate that the average genome size of sauropodomorphs was 2.02 pg (range of species means: 1.77-2.21 pg), a value in the upper range of extant birds (mean = 1.42 pg, range: 0.97-2.16 pg) and near the average for extant non-avian reptiles (mean = 2.24 pg, range: 1.05-5.44 pg). The results suggest that the variation in size and architecture of genomes in extinct dinosaurs was lower than the variation found in mammals. A substantial difference in genome size separates the two major clades within dinosaurs, Ornithischia (large genomes) and Saurischia (moderate to small genomes). We find no relationship between body size and estimated genome size in extinct dinosaurs, which suggests that neutral forces did not dominate the evolution of genome size in this group.

  19. Sauropod dinosaurs evolved moderately sized genomes unrelated to body size

    PubMed Central

    Organ, Chris L.; Brusatte, Stephen L.; Stein, Koen

    2009-01-01

    Sauropodomorph dinosaurs include the largest land animals to have ever lived, some reaching up to 10 times the mass of an African elephant. Despite their status defining the upper range for body size in land animals, it remains unknown whether sauropodomorphs evolved larger-sized genomes than non-avian theropods, their sister taxon, or whether a relationship exists between genome size and body size in dinosaurs, two questions critical for understanding broad patterns of genome evolution in dinosaurs. Here we report inferences of genome size for 10 sauropodomorph taxa. The estimates are derived from a Bayesian phylogenetic generalized least squares approach that generates posterior distributions of regression models relating genome size to osteocyte lacunae volume in extant tetrapods. We estimate that the average genome size of sauropodomorphs was 2.02 pg (range of species means: 1.77–2.21 pg), a value in the upper range of extant birds (mean = 1.42 pg, range: 0.97–2.16 pg) and near the average for extant non-avian reptiles (mean = 2.24 pg, range: 1.05–5.44 pg). The results suggest that the variation in size and architecture of genomes in extinct dinosaurs was lower than the variation found in mammals. A substantial difference in genome size separates the two major clades within dinosaurs, Ornithischia (large genomes) and Saurischia (moderate to small genomes). We find no relationship between body size and estimated genome size in extinct dinosaurs, which suggests that neutral forces did not dominate the evolution of genome size in this group. PMID:19793755

  20. Influence of individual body size on reproductive traits in Melanopline grasshoppers (Orthoptera: Acrididae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Body size is a fundamental trait of an organism, affecting most aspects of its performance, including reproduction. Numerous biotic and environmental factors can influence individual body size and reproduction in grasshoppers. Using data from four experiments, I examined intraspecific relationships ...

  1. Increases in disturbance and reductions in habitat size interact to suppress predator body size.

    PubMed

    Jellyman, Phillip G; McHugh, Peter A; McIntosh, Angus R

    2014-05-01

    Food webs are strongly size-structured so will be vulnerable to changes in environmental factors that affect large predators. However, mechanistic understanding of environmental controls of top predator size is poorly developed. We used streams to investigate how predator body size is altered by three fundamental climate change stressors: reductions in habitat size, increases in disturbance and warmer temperatures. Using new survey data from 74 streams, we showed that habitat size and disturbance were the most important stressors influencing predator body size. A synergistic interaction between that habitat size and disturbance due to flooding meant the sizes of predatory fishes peaked in large, benign habitats and their body size decreased as habitats became either smaller or harsher. These patterns were supported by experiments indicating that habitat-size reductions and increased flood disturbance decreased both the abundance and biomass of large predators. This research indicates that interacting climate change stressors can influence predator body size, resulting in smaller predators than would be predicted from examining an environmental factor in isolation. Thus, climate-induced changes to key interacting environmental factors are likely to have synergistic impacts on predator body size which, because of their influence on the strength of biological interactions, will have far-reaching effects on food-web responses to global environmental change.

  2. 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

  3. 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.

  4. Body Size Evolution Across the Geozoic

    NASA Astrophysics Data System (ADS)

    Smith, Felisa A.; Payne, Jonathan L.; Heim, Noel A.; Balk, Meghan A.; Finnegan, Seth; Kowalewski, Michał; Lyons, S. Kathleen; McClain, Craig R.; McShea, Daniel W.; Novack-Gottshall, Philip M.; Anich, Paula Spaeth; Wang, Steve C.

    2016-06-01

    The Geozoic encompasses the 3.6 Ga interval in Earth history when life has existed. Over this time, life has diversified from exclusively tiny, single-celled organisms to include large, complex multicellular forms. Just how and why this diversification occurred has been a major area of interest for paleontologists and evolutionary biologists for centuries. Here, we compile data on organism size throughout the Geozoic fossil record for the three domains of life. We describe canonical trends in the evolution of body size, synthesize current understanding of the patterns and causal mechanisms at various hierarchical scales, and discuss the biological and geological consequences of variation in organismal size.

  5. The body size dependence of trophic cascades.

    PubMed

    DeLong, John P; Gilbert, Benjamin; Shurin, Jonathan B; Savage, Van M; Barton, Brandon T; Clements, Christopher F; Dell, Anthony I; Greig, Hamish S; Harley, Christopher D G; Kratina, Pavel; McCann, Kevin S; Tunney, Tyler D; Vasseur, David A; O'Connor, Mary I

    2015-03-01

    Trophic cascades are indirect positive effects of predators on resources via control of intermediate consumers. Larger-bodied predators appear to induce stronger trophic cascades (a greater rebound of resource density toward carrying capacity), but how this happens is unknown because we lack a clear depiction of how the strength of trophic cascades is determined. Using consumer resource models, we first show that the strength of a trophic cascade has an upper limit set by the interaction strength between the basal trophic group and its consumer and that this limit is approached as the interaction strength between the consumer and its predator increases. We then express the strength of a trophic cascade explicitly in terms of predator body size and use two independent parameter sets to calculate how the strength of a trophic cascade depends on predator size. Both parameter sets predict a positive effect of predator size on the strength of a trophic cascade, driven mostly by the body size dependence of the interaction strength between the first two trophic levels. Our results support previous empirical findings and suggest that the loss of larger predators will have greater consequences on trophic control and biomass structure in food webs than the loss of smaller predators.

  6. 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.

  7. Human vocal attractiveness as signaled by body size projection.

    PubMed

    Xu, Yi; Lee, Albert; Wu, Wing-Li; Liu, Xuan; Birkholz, Peter

    2013-01-01

    Voice, as a secondary sexual characteristic, is known to affect the perceived attractiveness of human individuals. But the underlying mechanism of vocal attractiveness has remained unclear. Here, we presented human listeners with acoustically altered natural sentences and fully synthetic sentences with systematically manipulated pitch, formants and voice quality based on a principle of body size projection reported for animal calls and emotional human vocal expressions. The results show that male listeners preferred a female voice that signals a small body size, with relatively high pitch, wide formant dispersion and breathy voice, while female listeners preferred a male voice that signals a large body size with low pitch and narrow formant dispersion. Interestingly, however, male vocal attractiveness was also enhanced by breathiness, which presumably softened the aggressiveness associated with a large body size. These results, together with the additional finding that the same vocal dimensions also affect emotion judgment, indicate that humans still employ a vocal interaction strategy used in animal calls despite the development of complex language.

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

    PubMed Central

    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. PMID:24711966

  9. Body Size Mediated Coexistence in Swans

    PubMed Central

    Engelhardt, Katharina A. M.; Ritchie, Mark E.; Powell, James A.

    2014-01-01

    Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs) and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus) and trumpeter swans (Cygnus buccinator), a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata) tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a) had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b) were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource. PMID:24672347

  10. 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…

  11. 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.

  12. Body Weight Independently Affects Articular Cartilage Catabolism

    PubMed Central

    Denning, W. Matt; Winward, Jason G.; Pardo, Michael Becker; Hopkins, J. Ty; Seeley, Matthew K.

    2015-01-01

    Although obesity is associated with osteoarthritis, it is unclear whether body weight (BW) independently affects articular cartilage catabolism (i.e., independent from physiological factors that also accompany obesity). The primary purpose of this study was to evaluate the independent effect of BW on articular cartilage catabolism associated with walking. A secondary purpose was to determine how decreased BW influenced cardiovascular response due to walking. Twelve able-bodied subjects walked for 30 minutes on a lower-body positive pressure treadmill during three sessions: control (unadjusted BW), +40%BW, and -40%BW. Serum cartilage oligomeric matrix protein (COMP) was measured immediately before (baseline) and after, and 15 and 30 minutes after the walk. Heart rate (HR) and rate of perceived exertion (RPE) were measured every three minutes during the walk. Relative to baseline, average serum COMP concentration was 13% and 5% greater immediately after and 15 minutes after the walk. Immediately after the walk, serum COMP concentration was 14% greater for the +40%BW session than for the -40%BW session. HR and RPE were greater for the +40%BW session than for the other two sessions, but did not differ between the control and -40%BW sessions. BW independently influences acute articular cartilage catabolism and cardiovascular response due to walking: as BW increases, so does acute articular cartilage catabolism and cardiovascular response. These results indicate that lower-body positive pressure walking may benefit certain individuals by reducing acute articular cartilage catabolism, due to walking, while maintaining cardiovascular response. Key points Walking for 30 minutes with adjustments in body weight (normal body weight, +40% and -40% body weight) significantly influences articular cartilage catabolism, measured via serum COMP concentration. Compared to baseline levels, walking with +40% body weight and normal body weight both elicited significant increases in

  13. 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

  14. Framing body size among African American women and girls.

    PubMed

    Williams, Ellen P; Wyatt, Sharon B; Winters, Karen

    2013-09-01

    Obesity continues to affect African Americans in epidemic proportions, particularly among women and adolescent females. Perceptions, beliefs, behaviors, and body sizes of adolescents are associated with those of their mothers, yet little is known about the transgenerational meanings and experiences of obese African American adolescent girls and their mothers. An interpretive phenomenological study was conducted with seven African American adolescents between the ages of 11 and 17, and their adult female caregivers. Audio-taped interviews were transcribed and analyzed by a multicultural interpretive team. Two constitutive patterns and associated themes were identified. One pattern, 'Framing: sizing it up; sizing it down', with its three associated themes is presented. Mothers and daughters are engaged in multiple common practices in which they self-define body size, while protecting their self-esteem and self-image. This pattern illustrates how the women and girls created an image of their bodies as they confronted and acknowledged their self-perceptions, compared themselves to others in their environment, and evaluated themselves against specific parameters of acceptable size.

  15. How Tongue Size and Roughness Affect Lapping

    NASA Astrophysics Data System (ADS)

    Hubbard, M. J.; Hay, K. M.

    2012-10-01

    The biomechanics of domestic cat lapping (Felis catus) and domestic dog lapping (Canis familiaris) is currently under debate. Lapping mechanics in vertebrates with incomplete cheeks, such as cats and dogs, is a balance of inertia and the force of gravity likely optimized for ingestion and physical necessities. Physiology dictates vertebrate mass, which dictates vertebrate tongue size, which dictates lapping mechanics to achieve optimum liquid ingestion; with either touch lapping, scooping, or a hybrid lapping method. The physics of this optimized system then determines how high a column of liquid can be raised before it collapses due to gravity, and therefore, lapping frequency. Through tongue roughness model variation experiments it was found that pore-scale geometrical roughness does not appear to affect lapping or liquid uptake. Through tongue size model variation experiments it was found that there is a critical tongue radius in the range of 25 mm to 35 mm above which touch lapping is no longer an efficient way to uptake liquid. Vertebrates with incomplete cheeks may use a touch lapping method to ingest water if their tongue radius is less than this critical radius and use an alternative ingestion method if their tongue radius is larger.

  16. On being the right size: increased body size is associated with reduced telomere length under natural conditions.

    PubMed

    Ringsby, Thor Harald; Jensen, Henrik; Pärn, Henrik; Kvalnes, Thomas; Boner, Winnie; Gillespie, Robert; Holand, Håkon; Hagen, Ingerid Julie; Rønning, Bernt; Sæther, Bernt-Erik; Monaghan, Pat

    2015-12-07

    Evolution of body size is likely to involve trade-offs between body size, growth rate and longevity. Within species, larger body size is associated with faster growth and ageing, and reduced longevity, but the cellular processes driving these relationships are poorly understood. One mechanism that might play a key role in determining optimal body size is the relationship between body size and telomere dynamics. However, we know little about how telomere length is affected when selection for larger size is imposed in natural populations. We report here on the relationship between structural body size and telomere length in wild house sparrows at the beginning and end of a selection regime for larger parent size that was imposed for 4 years in an isolated population of house sparrows. A negative relationship between fledgling size and telomere length was present at the start of the selection; this was extended when fledgling size increased under the selection regime, demonstrating a persistent covariance between structural size and telomere length. Changes in telomere dynamics, either as a correlated trait or a consequence of larger size, could reduce potential longevity and the consequent trade-offs could thereby play an important role in the evolution of optimal body size.

  17. Selection on body size and sexual size dimorphism differs between host species in a seed-feeding beetle.

    PubMed

    Fox, C W; Czesak, M E

    2006-07-01

    Sexual size dimorphism varies substantially among populations and species but we have little understanding of the sources of selection generating this variation. We used path analysis to study how oviposition host affects selection on body size in a seed-feeding beetle (Stator limbatus) in which males contribute large ejaculates (nuptial gifts) to females. Females use nutrients in these ejaculates for egg production. Male body size, which affects ejaculate size, affects female fecundity and is thus under fecundity selection similar in magnitude to the fecundity selection on female body size. We show that when eggs are laid on a host on which larval mortality is low (seeds of Acacia greggii) fecundity predicts fitness very well and fecundity selection is the major source of selection on both male and female adult size. In contrast, when eggs are laid on a host on which larval mortality is high (seeds of Parkinsonia florida) fecundity poorly predicts fitness such that fecundity selection is relaxed on both male and female size. However, because egg size affects larval mortality on this poor host (P. florida) there is selection on female size via the female size --> egg size --> fitness path; this selection via egg size offsets the reduction in fecundity selection on female, but not male, body size. Thus, differences in host suitability (due to differences in larval mortality) affect the relative importance of two sources of selection on adult body size; fecundity selection on both male and female body size is lower on the poor quality host (P. florida) relative to the high quality host (A. greggii) whereas selection on female body size via effects of egg size on offspring survival (body size --> egg size --> fitness) is greater on the poor quality host relative to the high quality host. Because selection via the egg size path affects only females the difference in larval survival between hosts shifts the relative magnitude of selection on female vs. male size

  18. Longevity is not influenced by prenatal programming of body size.

    PubMed

    Conover, Cheryl A; Bale, Laurie K; Grell, Jacquelyn A; Mader, Jessica R; Mason, Megan A

    2010-08-01

    Insulin-like growth factor (IGF) signaling is essential for achieving optimal body size during fetal development, whereas, in the adult, IGFs are associated with aging and age-related diseases. However, it is unclear as to what extent lifespan is influenced by events that occur during development. Here, we provide direct evidence that the exceptional longevity of mice with altered IGF signaling is not linked to prenatal programming of body size. Mice null for pregnancy-associated plasma protein-A (PAPP-A), an IGF-binding protein proteinase that increases local IGF bioavailability, are 60-70% the size of their wild-type littermates at birth and have extended median and maximum lifespan of 30-40%. In this study, PAPP-A(-/-) mice whose body size was normalized during fetal development through disruption of IgfII imprinting did not lose their longevity advantage. Adult-specific moderation of IGF signaling through PAPP-A inhibition may present a unique opportunity to improve lifespan without affecting important aspects of early life physiology.

  19. Factish relations: Affective bodies in diabetes treatment.

    PubMed

    Danholt, Peter

    2013-07-01

    Chronic diseases pose a major challenge to contemporary western healthcare systems, and consequently there are numerous initiatives designed to meet these challenges. Patient empowerment is considered to be extremely important in chronic disease management. But what does it mean to become an 'active patient', managing a condition? This article argues that people are always active in shaping their agency and the agency of numerous others, and that we need to attend to these processes of configuration in order to better understand and conceptualize the problem of chronic disease management. This article analyses the daily practices of people with Type 2 Diabetes, with the use of what is described as the 'sociology of attachment' in the field of science and technology studies. The implications of seeing and analysing chronic conditions in this manner are that determinist understandings of chronic conditions are challenged. Accordingly, an experimental and constructive attitude towards the production and assembling of the chronically ill body is enabled. Such an attitude holds that relations with multiple other bodies and entities, such as technologies, the disease, medication and so on continuously and relentlessly affect how the condition unfolds and consequently, the room for interventional strategies and transformation of the chronically ill body is enlarged.

  20. 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.

  1. 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.

  2. Does teenage childbearing increase smoking, drinking and body size?

    PubMed

    Webbink, Dinand; Martin, Nicholas G; Visscher, Peter M

    2008-07-01

    This paper analyses the causal effect of teenage childbearing on smoking, drinking and body size using a sample of Australian twins and their relatives. Fixed effects estimates on samples of siblings, all twin pairs and identical twin pairs show that teenage mothers smoke more during their lives. Teen mothers tend to have a higher probability of being overweight, especially if they are older than 40 years. Their spouses are more likely to smoke and drink more. The quality of the spouse seems to be an important mechanism through which teenage childbearing affects subsequent maternal health.

  3. Dietary Habits and Body Size Perception of Elementary School Children

    ERIC Educational Resources Information Center

    Murimi, Mary W.

    2004-01-01

    This study assessed the attitudes and concerns of children in grades 1 through 5 regarding their perceived body size and ideal body size, and it assessed their Body Mass Index (BMI) and dietary habits. This study found an overweight prevalence of 11.4%, based on the children's BMI. Most of the overweight students were either African American or…

  4. Trade-offs in the evolution of bumblebee colony and body size: a comparative analysis.

    PubMed

    Cueva Del Castillo, Raúl; Sanabria-Urbán, Salomón; Serrano-Meneses, Martín Alejandro

    2015-09-01

    Trade-offs between life-history traits - such as fecundity and survival - have been demonstrated in several studies. In eusocial insects, the number of organisms and their body sizes can affect the fitness of the colony. Large-than-average body sizes as well as more individuals can improve a colony's thermoregulation, foraging efficiency, and fecundity. However, in bumblebees, large colonies and large body sizes depend largely on high temperatures and a large amount of food resources. Bumblebee taxa can be found in temperate and tropical regions of the world and differ markedly in their colony sizes and body sizes. Variation in colony size and body size may be explained by the costs and benefits associated with the evolutionary history of each species in a particular environment. In this study, we explored the effect of temperature and precipitation (the latter was used as an indirect indicator of food availability) on the colony and body size of twenty-one bumblebee taxa. A comparative analysis controlling for phylogenetic effects as well as for the body size of queens, workers, and males in bumblebee taxa from temperate and tropical regions indicated that both temperature and precipitation affect colony and body size. We found a negative association between colony size and the rainiest trimester, and a positive association between the colony size and the warmest month of the year. In addition, male bumblebees tend to evolve larger body sizes in places where the rain occurs mostly in the summer and the overall temperature is warmer. Moreover, we found a negative relationship between colony size and body sizes of queens, workers, and males, suggesting potential trade-offs in the evolution of bumblebee colony and body size.

  5. 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.

  6. 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

  7. The effects of exercise on body satisfaction and affect.

    PubMed

    Lepage, Marie L; Crowther, Janis H

    2010-03-01

    This research used ecological momentary assessment to examine the effects of exercise on state body dissatisfaction and affect in 33 undergraduate females with high trait body dissatisfaction and 28 with low trait body dissatisfaction who exercised at least three times weekly. Trait body dissatisfaction was investigated as a moderator of the effects of exercise as well as different motivations for exercise. Results indicated all participants experienced lower state body dissatisfaction and negative affect and greater positive affect post-exercise. Trait body dissatisfaction moderated the association between motivations and exercise effects. Appearance and weight motivations were related to higher state body dissatisfaction for all individuals. Fitness and health motivations were related to higher state body dissatisfaction for high trait body dissatisfied individuals and lower state body dissatisfaction for low trait body dissatisfied individuals. Thus, although exercise has positive effects on body dissatisfaction and affect for high frequency exercisers, their exercise motivations impact these effects.

  8. Ballroom dance and body size perception.

    PubMed

    Fonseca, Cristiane Costa; Thurm, Bianca Elisabeth; Vecchi, Rodrigo Luiz; Gama, Eliane Florencio

    2014-10-01

    Ballroom dancing consists in the performance of rhythmic movements guided by music, which provide sensorimotor integration and stimulate feelings. The body schema is the unconscious sensorimotor representation that allows the individual to perceive his anatomical body in space. Comprising tactile, proprioceptive, kinesthetic, and environmental information, it is directly related to movement. The aim of this study was to investigate the influence of non-competitive practice of ballroom dancing on body perception. The projection point test was applied to 30 volunteers before and after a period of 3 mo.; 15 controls attended lectures on body perception and 15 participants took dance lessons. It was observed that ballroom dancing brought perceptual benefits for those who practiced it.

  9. 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.

  10. 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.

  11. Men's facial masculinity: when (body) size matters.

    PubMed

    Holzleitner, Iris J; Hunter, David W; Tiddeman, Bernard P; Seck, Alassane; Re, Daniel E; Perrett, David I

    2014-01-01

    Recent studies suggest that judgments of facial masculinity reflect more than sexually dimorphic shape. Here, we investigated whether the perception of masculinity is influenced by facial cues to body height and weight. We used the average differences in three-dimensional face shape of forty men and forty women to compute a morphological masculinity score, and derived analogous measures for facial correlates of height and weight based on the average face shape of short and tall, and light and heavy men. We found that facial cues to body height and weight had substantial and independent effects on the perception of masculinity. Our findings suggest that men are perceived as more masculine if they appear taller and heavier, independent of how much their face shape differs from women's. We describe a simple method to quantify how body traits are reflected in the face and to define the physical basis of psychological attributions.

  12. Vertebral Adaptations to Large Body Size in Theropod Dinosaurs

    PubMed Central

    Wilson, John P.; Woodruff, D. Cary; Gardner, Jacob D.; Flora, Holley M.; Horner, John R.; Organ, Chris L.

    2016-01-01

    Rugose projections on the anterior and posterior aspects of vertebral neural spines appear throughout Amniota and result from the mineralization of the supraspinous and interspinous ligaments via metaplasia, the process of permanent tissue-type transformation. In mammals, this metaplasia is generally pathological or stress induced, but is a normal part of development in some clades of birds. Such structures, though phylogenetically sporadic, appear throughout the fossil record of non-avian theropod dinosaurs, yet their physiological and adaptive significance has remained unexamined. Here we show novel histologic and phylogenetic evidence that neural spine projections were a physiological response to biomechanical stress in large-bodied theropod species. Metaplastic projections also appear to vary between immature and mature individuals of the same species, with immature animals either lacking them or exhibiting smaller projections, supporting the hypothesis that these structures develop through ontogeny as a result of increasing bending stress subjected to the spinal column. Metaplastic mineralization of spinal ligaments would likely affect the flexibility of the spinal column, increasing passive support for body weight. A stiff spinal column would also provide biomechanical support for the primary hip flexors and, therefore, may have played a role in locomotor efficiency and mobility in large-bodied species. This new association of interspinal ligament metaplasia in Theropoda with large body size contributes additional insight to our understanding of the diverse biomechanical coping mechanisms developed throughout Dinosauria, and stresses the significance of phylogenetic methods when testing for biological trends, evolutionary or not. PMID:27442509

  13. No Latitudinal Trends in Body Size of Foraminifera

    NASA Astrophysics Data System (ADS)

    Liao, Z.; Payne, J.; Seixas, G.

    2012-12-01

    Many organisms, such as penguins and polar bears, follow Bergmann's rule, which states that body size of animals tends to increase as temperature decreases, and thus as latitude increases toward to poles. A study of marine mollusk bivalves across a latitudinal gradient found no correlation between body size and latitude along the North American Pacific Coast, suggesting that the body size of marine bivalves might be controlled by other factors. This posed the question: Is there a lack of correlation between latitude and body size for all marine invertebrates or is it unique to marine bivalves? In this study, we examined four suborders of benthic foraminifera, Lagenina, Miliolina, Rotaliina, and Textulariina, a diverse phylum of amoeboid protists, to determine the relationship between body size and latitude within and across suborders at the global scale. We measured the shell (test) dimensions of foraminifera from a compilation of monograph images of type specimens. The mean test size as well as the maximum body size of those foraminifera suborders does not vary with increasing latitude. Our results show that foraminifera do not follow Bergmann's rule, consistent with the body size distribution pattern observed in marine bivalves. Different biological and environmental factors that vary between foraminifera suborders, such as life habitats, behaviors, and physiology, might have a greater influence on body size distributions.

  14. Geographic variation in body size and sexual size dimorphism of a seed-feeding beetle.

    PubMed

    Stillwell, R Craig; Morse, Geoffrey E; Fox, Charles W

    2007-09-01

    Body size of many animals varies with latitude: body size is either larger at higher latitudes (Bergmann's rule) or smaller at higher latitudes (converse Bergmann's rule). However, the causes underlying these patterns are poorly understood. Also, studies rarely explore how sexual size dimorphism varies with latitude. Here we investigate geographic variation in body size and sexual size dimorphism of the seed-feeding beetle Stator limbatus, collected from 95 locations along a 38 degrees range in latitude. We examine 14 variables to test whether clines in environmental factors are adequate to explain geographic patterns of body size. We found that body size and sexual size dimorphism of S. limbatus varied considerably with latitude; beetles were smaller but more dimorphic at lower latitudes. Body size was not correlated with a gradient in mean temperature, contrary to the commonly accepted hypothesis that clines are produced by latitudinal gradients in temperature. Instead, we found that three factors were adequate to explain the cline in body size: clinal variation in host plant seed size, moisture (humidity), and seasonality (variance in humidity, precipitation, and temperature). We also found that the cline in sexual size dimorphism was partially explainable by a gradient in moisture, though moisture alone was not sufficient to explain the cline. Other ecological or environmental variables must necessarily contribute to differences in selection on male versus female body size. The main implications of our study are that the sexes differ in the magnitude of clinal variation in body size, creating latitudinal variation in sexual size dimorphism, and that clines in body size of seed beetles are likely influenced by variation in host seed size, water availability, and seasonality.

  15. Biodiversity and body size are linked across metazoans

    PubMed Central

    McClain, Craig R.; Boyer, Alison G.

    2009-01-01

    Body size variation across the Metazoa is immense, encompassing 17 orders of magnitude in biovolume. Factors driving this extreme diversification in size and the consequences of size variation for biological processes remain poorly resolved. Species diversity is invoked as both a predictor and a result of size variation, and theory predicts a strong correlation between the two. However, evidence has been presented both supporting and contradicting such a relationship. Here, we use a new comprehensive dataset for maximum and minimum body sizes across all metazoan phyla to show that species diversity is strongly correlated with minimum size, maximum size and consequently intra-phylum variation. Similar patterns are also observed within birds and mammals. The observations point to several fundamental linkages between species diversification and body size variation through the evolution of animal life. PMID:19324730

  16. 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.

  17. Illusory Changes in Body Size Modulate Body Satisfaction in a Way That Is Related to Non-Clinical Eating Disorder Psychopathology

    PubMed Central

    Preston, Catherine; Ehrsson, H. Henrik

    2014-01-01

    Historically, body size overestimation has been linked to abnormal levels of body dissatisfaction found in eating disorders. However, recently this relationship has been called into question. Indeed, despite a link between how we perceive and how we feel about our body seeming intuitive, until now lack of an experimental method to manipulate body size has meant that a causal link, even in healthy participants, has remained elusive. Recent developments in body perception research demonstrate that the perceptual experience of the body can be readily manipulated using multisensory illusions. The current study exploits such illusions to modulate perceived body size in an attempt to influence body satisfaction. Participants were presented with stereoscopic video images of slimmer and wider mannequin bodies viewed through head-mounted displays from first person perspective. Illusory ownership was induced by synchronously stroking the seen mannequin body with the unseen real body. Pre and post-illusion affective and perceptual measures captured changes in perceived body size and body satisfaction. Illusory ownership of a slimmer body resulted in participants perceiving their actual body as slimmer and giving higher ratings of body satisfaction demonstrating a direct link between perceptual and affective body representations. Change in body satisfaction following illusory ownership of a wider body, however, was related to degree of (non-clinical) eating disorder psychopathology, which can be linked to fluctuating body representations found in clinical samples. The results suggest that body perception is linked to body satisfaction and may be of importance for eating disorder symptomology. PMID:24465698

  18. Body size is negatively correlated with trophic position among cyprinids.

    PubMed

    Burress, Edward D; Holcomb, Jordan M; Bonato, Karine Orlandi; Armbruster, Jonathan W

    2016-05-01

    Body size has many ecological and evolutionary implications that extend across multiple levels of organization. Body size is often positively correlated with species traits such as metabolism, prey size and trophic position (TP) due to physiological and mechanical constraints. We used stable isotope analysis to quantify TP among minnows across multiple assemblages that differed in their species composition, diversity and food web structure. Body size significantly predicted TP across different lineages and assemblages, and indicated a significant negative relationship. The observed negative relationship between body size and TP is contrary to conventional knowledge, and is likely to have arisen owing to highly clade-specific patterns, such that clades consist of either large benthic species or small pelagic species. Cyprinids probably subvert the physiological and mechanical constraints that generally produce a positive relationship between body size and TP using anatomical modifications and by consuming small-bodied prey, respectively. The need for herbivorous cyprinids to digest cellulose-rich foods probably selected for larger bodies to accommodate longer intestinal tracts and thereby to facilitate digestion of nutrient-poor resources, such as algae. Therefore, body size and TP are likely to have coevolved in cyprinids in association with specialization along the benthic to pelagic resource axis.

  19. Body size is negatively correlated with trophic position among cyprinids

    PubMed Central

    Burress, Edward D.; Holcomb, Jordan M.; Bonato, Karine Orlandi; Armbruster, Jonathan W.

    2016-01-01

    Body size has many ecological and evolutionary implications that extend across multiple levels of organization. Body size is often positively correlated with species traits such as metabolism, prey size and trophic position (TP) due to physiological and mechanical constraints. We used stable isotope analysis to quantify TP among minnows across multiple assemblages that differed in their species composition, diversity and food web structure. Body size significantly predicted TP across different lineages and assemblages, and indicated a significant negative relationship. The observed negative relationship between body size and TP is contrary to conventional knowledge, and is likely to have arisen owing to highly clade-specific patterns, such that clades consist of either large benthic species or small pelagic species. Cyprinids probably subvert the physiological and mechanical constraints that generally produce a positive relationship between body size and TP using anatomical modifications and by consuming small-bodied prey, respectively. The need for herbivorous cyprinids to digest cellulose-rich foods probably selected for larger bodies to accommodate longer intestinal tracts and thereby to facilitate digestion of nutrient-poor resources, such as algae. Therefore, body size and TP are likely to have coevolved in cyprinids in association with specialization along the benthic to pelagic resource axis. PMID:27293777

  20. Trophic strategies, animal diversity and body size

    USGS Publications Warehouse

    Lafferty, Kevin D.; Kuris, Armand M.

    2002-01-01

    A primary difference between predators and parasites is the number of victims that an individual attacks throughout a life-history stage. A key division within natural enemies is whether a successful attack eliminates the fitness of the prey or the host. A third distinctive axis for parasites is whether the host must die to further parasite development. The presence or absence of intensity-dependent pathology is a fourth factor that separates macroparasites from microparasites; this also distinguishes between social and solitary predators. Combining these four dichotomies defines seven types of parasitism, seven corresponding parasites, three forms of predation and, when one considers obligate and facultative combinations of these forms, four types of predator. Here, we argue that the energetics underlying the relative and absolute sizes of natural enemies and their victims is the primary selective factor responsible for the evolution of these different trophic strategies.

  1. Digit reduction, body size, and paedomorphosis in salamanders.

    PubMed

    Wiens, John J; Hoverman, Jason T

    2008-01-01

    The loss of digits is a widespread evolutionary trend in tetrapods which occurs in nearly every major clade. Alberch and Gale showed that the order in which digits are evolutionarily lost in salamanders versus frogs corresponds to the order in which they develop in each group, providing a classic example of developmental constraint. However, what actually drives the loss of digits in salamanders has remained unclear. Alberch and Gale suggested that loss of digits might be associated with paedomorphosis or with reduced body size. We test these hypotheses by combining morphometric and phylogenetic information for 98 species of salamanders. We find that digit loss is associated with both paedomorphosis and reduction in body size. However, these trends are surprisingly contradictory, in that paedomorphosis is significantly associated with an increase in body size in salamanders. Thus, much of the extreme digit reduction is found in the smaller species within paedomorphic clades that have, on average, unusually large body size. Our results show that the consequences of changes in body size on morphology are highly context dependent. We also show (possibly for the first time) a significant association between paedomorphosis and increased body size, rather than the expected association with reduced body size.

  2. Taylor's law and body size in exploited marine ecosystems.

    PubMed

    Cohen, Joel E; Plank, Michael J; Law, Richard

    2012-12-01

    Taylor's law (TL), which states that variance in population density is related to mean density via a power law, and density-mass allometry, which states that mean density is related to body mass via a power law, are two of the most widely observed patterns in ecology. Combining these two laws predicts that the variance in density is related to body mass via a power law (variance-mass allometry). Marine size spectra are known to exhibit density-mass allometry, but variance-mass allometry has not been investigated. We show that variance and body mass in unexploited size spectrum models are related by a power law, and that this leads to TL with an exponent slightly <2. These simulated relationships are disrupted less by balanced harvesting, in which fishing effort is spread across a wide range of body sizes, than by size-at-entry fishing, in which only fish above a certain size may legally be caught.

  3. 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

  4. Evidence for the higher importance of signal size over body size in aposematic signaling in insects.

    PubMed

    Remmel, Triinu; Tammarub, Toomas

    2011-01-01

    To understand the evolution of warning coloration, it is important to distinguish between different aspects of conspicuous color patterns. As an example, both pattern element size and body size of prey have been shown to enhance the effectiveness of warning signals. However, it is unclear whether the effect of body size is merely a side effect of proportionally increasing pattern elements, or if there is an effect of body size per se. These possibilities were evaluated by offering different sized artificial caterpillars with either fixed or proportionally increasing aposematic color signal elements to wild great tits, Parus major L. (Passeriformes: Paridae). The birds' hesitation time to attack each "caterpillar" was used as a measure of the warning effect. The hesitation time showed a significant, positive size-dependence with the caterpillars whose pattern elements increased proportionally with their body size. In contrast, no size dependence was found in the larvae with fixed-size signal elements. Such a difference in mortality curves is consistent with the idea that pattern element size is a more important aspect than body size in enhancing a warning signal. Since no evidence of an effect of body size per se on signal efficiency was found, this study does not support the hypothesis that aposematic insects gain more from large size than cryptic ones.

  5. Morphological characteristics of blood cells in monitor lizards: is erythrocyte size linked to actual body size?

    PubMed

    Frýdlová, Petra; Hnízdo, Jan; Chylíková, Lenka; Simková, Olga; Cikánová, Veronika; Velenský, Petr; Frynta, Daniel

    2013-04-01

    Blood cell morphology and count are not uniform across species. Recently, between-species comparisons revealed that the size of red blood cells is associated with body size in some lizard taxa, and this finding was interpreted in the context of the metabolic theory. In the present study, we examined the numbers and the size of blood cells in 2 species of monitor lizards, the mangrove-dwelling monitor (Varanus indicus) and the savannah monitor (V. exanthematicus), and we compared these traits in individuals of different body size. The results revealed that during the course of ontogeny, the size of red blood cells increases with body mass. Because the mass-specific metabolic rate decreases with body size and the cell volume-to-surface ratio decreases with the cell size, changes in the erythrocyte size might be the result of oxygen transport adjustment.

  6. 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

  7. 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.

  8. 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

  9. Modes of Brachiopod Body Size Evolution throughout the Phanerozoic Eon

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Payne, J.

    2012-12-01

    Body size correlates with numerous physiological and behavioral traits and is therefore one of the most important influences on the survival prospects of individuals and species. Patterns of body size evolution across taxa can therefore complement taxonomic diversity and geochemical proxy data in quantifying controls on long-term trends in the history of life. In contrast to widely available and synoptic taxonomic diversity data for fossil animal families and genera, however, no comprehensive size dataset exists, even for a single fossil animal phylum. For this study, we compiled a comprehensive, genus-level dataset of body sizes spanning the entire Phanerozoic for the phylum Brachiopoda. We use this dataset to examine statistical support for several possible modes of size evolution, in addition to environmental covariates: CO2, O2, and sea level. Brachiopod body size in the Phanerozoic followed two evolutionary modes: directional trend in the Early Paleozoic (Cambrian - Mississippian), and unbiased random walk from the Mississippian to the modern. We find no convincing correlation between trends in any single environmental parameter and brachiopod body size over time. The Paleozoic size increase follows Cope's Rule, and has been documented in many other marine invertebrates, while the Mesozoic size plateau has not been. This interval of size stability correlates with increased competition for resources from bivalves beginning during the Mesozoic Marine Revolution, and may be causally linked. The Late Mesozoic decline in size is an artifact of the improved sampling of smaller genera, many of which are less abundant than their Paleozoic ancestors. The Cenozoic brachiopod dataset is similarly incomplete. Biodiversity is decoupled from size dynamics even within the Paleozoic when brachiopods are on average becoming larger and more abundant, suggesting the presence of different controls. Our findings reveal that the dynamics of body size evolution changed over time in

  10. Body Size Evolution in Extant Oryzomyini Rodents: Cope's Rule or Miniaturization?

    PubMed Central

    Avaria-Llautureo, Jorge; Hernández, Cristián E.; Boric-Bargetto, Dusan; Canales-Aguirre, Cristian B.; Morales-Pallero, Bryan; Rodríguez-Serrano, Enrique

    2012-01-01

    At the macroevolutionary level, one of the first and most important hypotheses that proposes an evolutionary tendency in the evolution of body sizes is “Cope's rule". This rule has considerable empirical support in the fossil record and predicts that the size of species within a lineage increases over evolutionary time. Nevertheless, there is also a large amount of evidence indicating the opposite pattern of miniaturization over evolutionary time. A recent analysis using a single phylogenetic tree approach and a Bayesian based model of evolution found no evidence for Cope's rule in extant mammal species. Here we utilize a likelihood-based phylogenetic method, to test the evolutionary trend in body size, which considers phylogenetic uncertainty, to discern between Cope's rule and miniaturization, using extant Oryzomyini rodents as a study model. We evaluated body size trends using two principal predictions: (a) phylogenetically related species are more similar in their body size, than expected by chance; (b) body size increased (Cope's rule)/decreased (miniaturization) over time. Consequently the distribution of forces and/or constraints that affect the tendency are homogenous and generate this directional process from a small/large sized ancestor. Results showed that body size in the Oryzomyini tribe evolved according to phylogenetic relationships, with a positive trend, from a small sized ancestor. Our results support that the high diversity and specialization currently observed in the Oryzomyini tribe is a consequence of the evolutionary trend of increased body size, following and supporting Cope's rule. PMID:22509339

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

    PubMed

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

    2016-11-07

    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.

  12. Body size regulation and insulin-like growth factor signaling.

    PubMed

    Hyun, Seogang

    2013-07-01

    How animals achieve their specific body size is a fundamental, but still largely unresolved, biological question. Over the past decades, studies on the insect model system have provided some important insights into the process of body size determination and highlighted the importance of insulin/insulin-like growth factor signaling. Fat body, the Drosophila counterpart of liver and adipose tissue, senses nutrient availability and controls larval growth rate by modulating peripheral insulin signaling. Similarly, insulin-like growth factor I produced from liver and muscle promotes postnatal body growth in mammals. Organismal growth is tightly coupled with the process of sexual maturation wherein the sex steroid hormone attenuates body growth. This review summarizes some important findings from Drosophila and mammalian studies that shed light on the general mechanism of animal size determination.

  13. Efficiency of whole-body counter for various body size calculated by MCNP5 software.

    PubMed

    Krstic, D; Nikezic, D

    2012-11-01

    The efficiency of a whole-body counter for (137)Cs and (40)K was calculated using the MCNP5 code. The ORNL phantoms of a human body of different body sizes were applied in a sitting position in front of a detector. The aim was to investigate the dependence of efficiency on the body size (age) and the detector position with respect to the body and to estimate the accuracy of real measurements. The calculation work presented here is related to the NaI detector, which is available in the Serbian Whole-body Counter facility in Vinca Institute.

  14. Low temperature alteration processes affecting ultramafic bodies

    USGS Publications Warehouse

    Nesbitt, H.W.; Bricker, O.P.

    1978-01-01

    At low temperatures, in the presence of an aqueous solution, olivine and orthopyroxene are not stable relative to the hydrous phases brucite, serpentine and talc. Alteration of dunite and peridotite to serpentine or steatite bodies must therefore proceed via non-equilibrium processes. The compositions of natural solutions emanating from dunites and peridotites demonstrate that the dissolution of forsterite and/or enstatite is rapid compared with the precipitation of the hydrous phases; consequently, dissolution of anhydrous minerals controls the chemistry of such solutions. In the presence of an aqueous phase, precipitation of hydrous minerals is the rate-controlling step. Brucite-bearing and -deficient serpentinites alter at low temperature by non-equilibrium processes, as evidenced by the composition of natural solutions from these bodies. The solutions approach equilibrium with the least stable hydrous phase and, as a consequence, are supersaturated with other hydrous phases. Dissolution of the least stable phase is rapid compared to precipitation of other phases, so that the dissolving mineral controls the solution chemistry. Non-equilibrium alteration of anhydrous ultramafic bodies continues until at least one anhydrous phase equilibrates with brucite, chrysotile or talc. The lowest temperature (at a given pressure) at which this happens is defined by the reaction: 3H2O + 2Mg2SiO4 ??? Mg3Si2O5(OH)4 + Mg(OH)2 (Johannes, 1968, Contrib. Mineral. Petrol. 19, 309-315) so that non-equilibrium alteration may occur well into greenschist facies metamorphic conditions. ?? 1978.

  15. 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

  16. Effects of developmental change in body size on ectotherm body temperature and behavioral thermoregulation: caterpillars in a heat-stressed environment.

    PubMed

    Nielsen, Matthew E; Papaj, Daniel R

    2015-01-01

    Ectotherms increase in size dramatically during development, and this growth should have substantial effects on their body temperature and ability to thermoregulate. To better understand how this change in size affects temperature, we examined the direct effects of body size on body temperature in Battus philenor caterpillars, and also how body size affects both the expression and effectiveness of thermal refuge-seeking, a thermoregulatory behavior. Field studies of both live caterpillars and physical operative temperature models indicated that caterpillar body temperature increases with body size. The operative temperature models also showed that thermal refuges have a greater cooling effect for larger caterpillars, while a laboratory study found that larger caterpillars seek refuges at a lower temperature. Although the details may vary, similar connections between developmental growth, temperature, and thermoregulation should be common among ectotherms and greatly affect both their development and thermal ecology.

  17. Hydrodynamic drag of diving birds: effects of body size, body shape and feathers at steady speeds.

    PubMed

    Lovvorn, J; Liggins, G A; Borstad, M H; Calisal, S M; Mikkelsen, J

    2001-05-01

    For birds diving to depths where pressure has mostly reduced the buoyancy of air spaces, hydrodynamic drag is the main mechanical cost of steady swimming. Drag is strongly affected by body size and shape, so such differences among species should affect energy costs. Because flow around the body is complicated by the roughness and vibration of feathers, feathers must be considered in evaluating the effects of size and shape on drag. We investigated the effects of size, shape and feathers on the drag of avian divers ranging from wing-propelled auklets weighing 75 g to foot-propelled eiders weighing up to 2060 g. Laser scanning of body surfaces yielded digitized shapes that were averaged over several specimens per species and then used by a milling machine to cut foam models. These models were fitted with casts of the bill area, and their drag was compared with that of frozen specimens. Because of the roughness and vibration of the feathers, the drag of the frozen birds was 2-6 times that of the models. Plots of drag coefficient (C(D)) versus Reynolds number (Re) differed between the model and the frozen birds, with the pattern of difference varying with body shape. Thus, the drag of cast models or similar featherless shapes can differ both quantitatively and qualitatively from that of real birds. On the basis of a new towing method with no posts or stings that alter flow or angles of attack, the dimensionless C(D)/Re curves differed among a size gradient of five auklet species (75-100g) with similar shapes. Thus, extrapolation of C(D)/Re curves among related species must be performed with caution. At lower speeds, the C(D) at a given Re was generally higher for long-necked birds that swim with their neck extended (cormorants, grebes, some ducks) than for birds that swim with their head retracted (penguins, alcids), but this trend was reversed at high speeds. Because swimming birds actually travel at a range of instantaneous speeds during oscillatory strokes, species

  18. Gender, Body Size and Social Relations in American High Schools

    ERIC Educational Resources Information Center

    Crosnoe, Robert; Frank, Kenneth; Mueller, Anna Strassmann

    2008-01-01

    To investigate the role of body size in social networks, this study estimated cross-nested multilevel network models (p2) with longitudinal data from the 16 saturated schools in the National Longitudinal Study of Adolescent Health. As body mass index increased, the likelihood of being nominated by schoolmates as friends--but not the likelihood of…

  19. Relationship of metabolic rate to body size in Orthoptera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metabolic rate determines an individual’s rate of resource acquisition, assimilation, growth, survival, and reproduction. Studies involving a broad range of taxa and body sizes typically result in whole-organism metabolic rate scaling to the ¾ power of body mass. Competing models have been proposed ...

  20. The evolutionary history of cetacean brain and body size.

    PubMed

    Montgomery, Stephen H; Geisler, Jonathan H; McGowen, Michael R; Fox, Charlotte; Marino, Lori; Gatesy, John

    2013-11-01

    Cetaceans rival primates in brain size relative to body size and include species with the largest brains and biggest bodies to have ever evolved. Cetaceans are remarkably diverse, varying in both phenotypes by several orders of magnitude, with notable differences between the two extant suborders, Mysticeti and Odontoceti. We analyzed the evolutionary history of brain and body mass, and relative brain size measured by the encephalization quotient (EQ), using a data set of extinct and extant taxa to capture temporal variation in the mode and direction of evolution. Our results suggest that cetacean brain and body mass evolved under strong directional trends to increase through time, but decreases in EQ were widespread. Mysticetes have significantly lower EQs than odontocetes due to a shift in brain:body allometry following the divergence of the suborders, caused by rapid increases in body mass in Mysticeti and a period of body mass reduction in Odontoceti. The pattern in Cetacea contrasts with that in primates, which experienced strong trends to increase brain mass and relative brain size, but not body mass. We discuss what these analyses reveal about the convergent evolution of large brains, and highlight that until recently the most encephalized mammals were odontocetes, not primates.

  1. Using Amazon's Mechanical Turk website to measure accuracy of body size estimation and body dissatisfaction.

    PubMed

    Gardner, Rick M; Brown, Dana L; Boice, Russell

    2012-09-01

    This study investigated Amazon.com's website Mechanical Turk (MTurk) as a research tool for measuring body size estimation and dissatisfaction. 160 U.S. participants completed the BIAS-BD figural drawing scale and demographic questions posted on the MTurk website. The BIAS-BD consists of 17 drawings of various male and female body sizes based on anthropometric data corresponding to a range of 60% below to 140% above the average U.S. adult. Respondents selected a drawing that best reflected their current size and ideal size. Results revealed that respondents overestimated their body size by 6% and desired an ideal size 9.2% smaller than their perceived size. Findings are compared with three previous studies using the BIAS-BD scale. A general correspondence in findings between the four studies was found. We conclude that the MTurk can serve as a viable method for collecting data on the perceptual and attitudinal aspects of body image quickly and inexpensively.

  2. Body size preference among Yoruba in three Nigerian communities.

    PubMed

    Okoro, E O; Oyejola, B A; Etebu, E N; Sholagberu, H; Kolo, P M; Chijioke, A; Adebisi, S A

    2014-03-01

    Following our previous observation of an aversion to weight reduction in Nigerians with type 2 diabetes, we measured several parameters of body dimensions and preferences in otherwise healthy adults in three communities to study the phenomenon further. The study population of 524 participants (304 F) was 99.8% of Yoruba ethnic origin with a mean age of 43.9 ± 17.2 years. Females had a significantly (p > 0.001) higher body mass index (BMI), waist circumference, hip circumference compared to the males; the values being 24.55 ± 5.5 vs. 21.75 ± 3.71 kg/m(2); 84.98 ± 12.67 vs. 80.92 ± 9.85 cm; 96.32 ± 12.94 vs. 89.36 ± 8.06 cm, respectively. There was a high level of satisfaction amongst respondents with their body size (Kendall's t = 0.52, p < 0.001) which they also predicted with a high degree of certainty even without the prior use of a weighing scale. The relationship between current body size (CBI) and BMI emerged as CBI = 1.22 + 0.32 BMI. In the 41% of respondents who expressed unhappiness with their current body size, there was a strong aversion for a smaller body size and the preference was often for a bigger body figure. Strikingly, many more women than men were less dissatisfied with their bigger body sizes. Stepwise regression indicated that CBI and gender were the two most important variables that best related to casual blood sugar (RBS) among the factors entered. The mathematical relationship between these variables that emerged was: [Formula: see text] where gender = 0 for male and 1 for female. The results suggest that larger body sizes were positively viewed in these communities consistent with our previous observations in type 2 diabetes.

  3. Does affective touch influence the virtual reality full body illusion?

    PubMed

    de Jong, Jutta R; Keizer, Anouk; Engel, Manja M; Dijkerman, H Chris

    2017-03-13

    The sense of how we experience our physical body as our own represents a fundamental component of human self-awareness. Body ownership can be studied with bodily illusions which are generated by inducing a visuo-tactile conflict where individuals experience illusionary ownership over a fake body or body part, such as a rubber hand. Previous studies showed that different types of touch modulate the strength of experienced ownership over a rubber hand. Specifically, participants experienced more ownership after the rubber hand illusion was induced through affective touch vs non-affective touch. It is, however, unclear whether this effect would also occur for an entire fake body. The aim of this study was, therefore, to investigate whether affective touch modulates the strength of ownership in a virtual reality full body illusion. To elicit this illusion, we used slow (3 cm/s; affective touch) and fast (30 cm/s; non-affective touch) stroking velocities on the participants' abdomen. Both stroking velocities were performed either synchronous or asynchronous (control condition), while participants viewed a virtual body from a first-person-perspective. In our first study, we found that participants experienced more subjective ownership over a virtual body in the affective touch condition, compared to the non-affective touch condition. In our second study, we found higher levels of subjective ownership for synchronous stimulation, compared to asynchronous, for both touch conditions, but failed to replicate the findings from study 1 that show a difference between affective and non-affective touch. We, therefore, cannot conclude unequivocally that affective touch enhances the full-body illusion. Future research is required to study the effects of affective touch on body ownership.

  4. Body size, performance and fitness in galapagos marine iguanas.

    PubMed

    Wikelski, Martin; Romero, L Michael

    2003-07-01

    Complex organismal traits such as body size are influenced by innumerable selective pressures, making the prediction of evolutionary trajectories for those traits difficult. A potentially powerful way to predict fitness in natural systems is to study the composite response of individuals in terms of performance measures, such as foraging or reproductive performance. Once key performance measures are identified in this top-down approach, we can determine the underlying physiological mechanisms and gain predictive power over long-term evolutionary processes. Here we use marine iguanas as a model system where body size differs by more than one order of magnitude between island populations. We identified foraging efficiency as the main performance measure that constrains body size. Mechanistically, foraging performance is determined by food pasture height and the thermal environment, influencing intake and digestion. Stress hormones may be a flexible way of influencing an individual's response to low-food situations that may be caused by high population density, famines, or anthropogenic disturbances like oil spills. Reproductive performance, on the other hand, increases with body size and is mediated by higher survival of larger hatchlings from larger females and increased mating success of larger males. Reproductive performance of males may be adjusted via plastic hormonal feedback mechanisms that allow individuals to assess their social rank annually within the current population size structure. When integrated, these data suggest that reproductive performance favors increased body size (influenced by reproductive hormones), with an overall limit imposed by foraging performance (influenced by stress hormones). Based on our mechanistic understanding of individual performances we predicted an evolutionary increase in maximum body size caused by global warming trends. We support this prediction using specimens collected during 1905. We also show in a common

  5. Body position affects performance in untrained cyclists

    PubMed Central

    Ashe, M; Scroop, G; Frisken, P; Amery, C; Wilkins, M; Khan, K

    2003-01-01

    Objective: To compare cardiovascular and ventilatory variables in upright versus aero cycle ergometry at submaximal and maximal exercise intensities in untrained cyclists. Method: Ten physically active men (mean (SD) age 19.1 (1.10) years) who were unfamiliar with aerobars underwent maximal exercise testing and steady state cycling at 50, 100, and 150 W. Results: Participants had significantly greater maxima for oxygen uptake (VO2), ventilation, heart rate, and workload maximum in the upright position. During steady state cycling at the three workloads, VO2 (ml/kg/min) and gross mechanical efficiency were significantly greater in the upright position. Conclusions: In untrained subjects performing with maximal effort, the upright position permits greater VO2, ventilation, heart rate, and workload maxima. Further, in the steady state, exercise cycling may be less costly in the upright position. For this reason, untrained cyclists need to weigh body position effects against the well known aerodynamic advantages of the aero position. PMID:14514538

  6. 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

  7. Human Body Size in Military Aircraft and Personal Equipment

    DTIC Science & Technology

    1946-06-01

    and engineer. The use of cramped spaces such .s gun turrets, catwalks , etc., involves quite as much the design and sizing of he personal equipment...human body size are concerned. The concept of writing specifications on the man which are as definite and demanding as any of those written on any type of...incorporate to the fullest extent the consideration of the size of human beings, and, also, that every considera- tion should be made in a cockpit design to

  8. Ostracod Body Size Change Across Space and Time

    NASA Astrophysics Data System (ADS)

    Nolen, L.; Llarena, L. A.; Saux, J.; Heim, N. A.; Payne, J.

    2014-12-01

    Many factors drive evolution, although it is not always clear which factors are more influential. Miller et al. (2009) found that there is a change in geographic disparity in diversity in marine biotas over time. We tested if there was also geographic disparity in body size during different epochs. We used marine ostracods, which are tiny crustaceans, as a study group for this analysis. We also studied which factor is more influential in body size change: distance or time. We compared the mean body size from different geologic time intervals as well as the mean body size from different locations for each epoch. We grouped ostracod occurrences from the Paleobiology Database into 10º x 10º grid cells on a paleogeographic map. Then we calculated the difference in mean size and the distance between the grid cells containing specimens. Our size data came from the Ellis & Messina"Catalogue of Ostracod" as well as the"Treatise on Invertebrate Paleontology". Sizes were calculated by applying the formula for the volume of an ellipsoid to three linear dimensions of the ostracod carapace (anteroposterior, dorsoventral, and right-left lengths). Throughout this analysis we have come to the realization that there is a trend in ostracods towards smaller size over time. Therefore there is also a trend through time of decreasing difference in size between occurrences in different grid cells. However, if time is not taken into account, there is no correlation between size and geographic distance. This may be attributed to the fact that one might not expect a big size difference between locations that are far apart but still at a similar latitude (for example, at the equator). This analysis suggests that distance alone is not the main factor in driving changes in ostracod size over time.

  9. Directionality theory and the evolution of body size.

    PubMed

    Demetrius, L

    2000-12-07

    Directionality theory, a dynamic theory of evolution that integrates population genetics with demography, is based on the concept of evolutionary entropy, a measure of the variability in the age of reproducing individuals in a population. The main tenets of the theory are three principles relating the response to the ecological constraints a population experiences, with trends in entropy as the population evolves under mutation and natural selection. (i) Stationary size or fluctuations around a stationary size (bounded growth): a unidirectional increase in entropy; (ii) prolonged episodes of exponential growth (unbounded growth), large population size: a unidirectional decrease in entropy; and (iii) prolonged episodes of exponential growth (unbounded growth), small population size: random, non-directional change in entropy. We invoke these principles, together with an allometric relationship between entropy, and the morphometric variable body size, to provide evolutionary explanations of three empirical patterns pertaining to trends in body size, namely (i) Cope's rule, the tendency towards size increase within phyletic lineages; (ii) the island rule, which pertains to changes in body size that occur as species migrate from mainland populations to colonize island habitats; and (iii) Bergmann's rule, the tendency towards size increase with increasing latitude. The observation that these ecotypic patterns can be explained in terms of the directionality principles for entropy underscores the significance of evolutionary entropy as a unifying concept in forging a link between micro-evolution, the dynamics of gene frequency change, and macro-evolution, dynamic changes in morphometric variables.

  10. Effects of allometry, productivity and lifestyle on rates and limits of body size evolution

    PubMed Central

    Okie, Jordan G.; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Evans, Alistair R.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Saarinen, Juha J.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica; Uhen, Mark D.; Sibly, Richard M.

    2013-01-01

    Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates individual productivity, the lifestyle component of the slow–fast life-history continuum, and the allometric scaling of generation time to predict a clade's evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during diversifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow–fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological diversity. PMID:23760865

  11. Quantifying the Effects of Predator and Prey Body Size on Sea Star Feeding Behaviors.

    PubMed

    Gooding, Rebecca A; Harley, Christopher D G

    2015-06-01

    Body size plays a crucial role in determining the strength of species interactions, population dynamics, and community structure. We measured how changes in body size affect the trophic relationship between the sea star Pisaster ochraceus and its prey, the mussel Mytilus trossulus. We tested the effects of a wide range of predator and prey sizes on sea stars' prey-size preference, feeding rate, and prey tissue consumption. We found that preferred prey size increased with sea star size. Pisaster consumption rate (mussels consumed per day) and tissue intake rate (grams of tissue consumed per day) also increased with sea star size. Pisaster consumption rate, but not tissue intake rate, decreased with increasing mussel size. Juvenile sea stars preferred the most profitable prey sizes-that is, those that maximized tissue consumed per unit handling time. When adult sea stars were offered larger, more profitable mussels, tissue intake rates (grams per day) tended to increase, although this relationship was not statistically significant. Our results indicate that the Pisaster-Mytilus interaction depends on the sizes of both predator and prey, that predation rates are sensitive to even small changes in body size, and that shifts in size distributions may affect predator energetics and prey numbers differently depending on the factors that limit tissue consumption rates.

  12. Perceived body size versus healthy body size and physical activity among adolescents - Results of a national survey.

    PubMed

    Zach, Sima; Zeev, Aviva; Dunsky, Ayelet; Goldbourt, Uri; Shimony, Tal; Goldsmith, Rebecca; Netz, Yael

    2013-01-01

    This study examined whether body perception (BP) and body satisfaction (BS) among adolescents correspond with healthy body size criteria as recommended by various world health authorities, and assessed the relationships between BP and BS and physical activity (PA) among adolescents. Participants included 6274 Israeli boys and girls from grades 7-12 who took part in the first Israeli Health and Nutrition Youth survey. Data regarding their BP and BS, body mass index (BMI) and PA were gathered. Among the overweight and obese participants, 66.4% and 40.6% of the boys, respectively, and 46.7% and 26.1% of the girls, respectively, perceived their body shape and size as satisfactory (OK). Another important finding was that overweight and obese girls were three times more active than underweight girls, and the highest per cent of active boys appeared among the overweight boys or those who perceived themselves as fat. Regression analyses revealed that BMI, gender and age accounted for 29.8% of the variance in participants' BP; BMI, gender and age accounted for 22.1% of BS variance, and PA was not related to either BP or BS. In conclusion, adolescents do not perceive their body according to healthy body size criteria recommended by various world health authorities. In addition, PA as a variable does not explain body image. Therefore, increasing body awareness seems to be a fundamental step in programs that aim to reduce obesity.

  13. 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.

  14. Perception of biological motion from size-invariant body representations

    PubMed Central

    Lappe, Markus; Wittinghofer, Karin; de Lussanet, Marc H. E.

    2015-01-01

    The visual recognition of action is one of the socially most important and computationally demanding capacities of the human visual system. It combines visual shape recognition with complex non-rigid motion perception. Action presented as a point-light animation is a striking visual experience for anyone who sees it for the first time. Information about the shape and posture of the human body is sparse in point-light animations, but it is essential for action recognition. In the posturo-temporal filter model of biological motion perception posture information is picked up by visual neurons tuned to the form of the human body before body motion is calculated. We tested whether point-light stimuli are processed through posture recognition of the human body form by using a typical feature of form recognition, namely size invariance. We constructed a point-light stimulus that can only be perceived through a size-invariant mechanism. This stimulus changes rapidly in size from one image to the next. It thus disrupts continuity of early visuo-spatial properties but maintains continuity of the body posture representation. Despite this massive manipulation at the visuo-spatial level, size-changing point-light figures are spontaneously recognized by naive observers, and support discrimination of human body motion. PMID:25852505

  15. 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.

  16. Body size and predatory performance in wolves: Is bigger better?

    USGS Publications Warehouse

    MacNulty, D.R.; Smith, D.W.; Mech, L.D.; Eberly, L.E.

    2009-01-01

    Large body size hinders locomotor performance in ways that may lead to trade-offs in predator foraging ability that limit the net predatory benefit of larger size. For example, size-related improvements in handling prey may come at the expense of pursuing prey and thus negate any enhancement in overall predatory performance due to increasing size. 2. This hypothesis was tested with longitudinal data from repeated observations of 94 individually known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park, USA. Wolf size was estimated from an individually based sex-specific growth model derived from body mass measurements of 304 wolves. 3. Larger size granted individual wolves a net predatory advantage despite substantial variation in its effect on the performance of different predatory tasks; larger size improved performance of a strength-related task (grappling and subduing elk) but failed to improve performance of a locomotor-related task (selecting an elk from a group) for wolves > 39 kg. 4. Sexual dimorphism in wolf size also explained why males outperformed females in each of the three tasks considered (attacking, selecting, and killing). 5. These findings support the generalization that bigger predators are overall better hunters, but they also indicate that increasing size ultimately limits elements of predatory behaviour that require superior locomotor performance. We argue that this could potentially narrow the dietary niche of larger carnivores as well as limit the evolution of larger size if prey are substantially more difficult to pursue than to handle. ?? 2009 British Ecological Society.

  17. Body size and predatory performance in wolves: is bigger better?

    PubMed

    MacNulty, Daniel R; Smith, Douglas W; Mech, L David; Eberly, Lynn E

    2009-05-01

    1. Large body size hinders locomotor performance in ways that may lead to trade-offs in predator foraging ability that limit the net predatory benefit of larger size. For example, size-related improvements in handling prey may come at the expense of pursuing prey and thus negate any enhancement in overall predatory performance due to increasing size. 2. This hypothesis was tested with longitudinal data from repeated observations of 94 individually known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park, USA. Wolf size was estimated from an individually based sex-specific growth model derived from body mass measurements of 304 wolves. 3. Larger size granted individual wolves a net predatory advantage despite substantial variation in its effect on the performance of different predatory tasks; larger size improved performance of a strength-related task (grappling and subduing elk) but failed to improve performance of a locomotor-related task (selecting an elk from a group) for wolves > 39 kg. 4. Sexual dimorphism in wolf size also explained why males outperformed females in each of the three tasks considered (attacking, selecting, and killing). 5. These findings support the generalization that bigger predators are overall better hunters, but they also indicate that increasing size ultimately limits elements of predatory behaviour that require superior locomotor performance. We argue that this could potentially narrow the dietary niche of larger carnivores as well as limit the evolution of larger size if prey are substantially more difficult to pursue than to handle.

  18. 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

  19. Environmental influences on the evolution of body size in Ammonoids

    NASA Astrophysics Data System (ADS)

    Hines, S.; Khong, C.; Pelagio, M.; Seixas, G.; Payne, J.

    2012-12-01

    A major debate in evolutionary biology and paleobiology focuses on the relative importance of ecological interactions between species versus changes in the physical environment in governing large-scale evolutionary patterns. Body size is among the most important traits of any organism, and so identifying the factors that influence size evolution can shed light on both the causes and consequences of many major evolutionary trends. However, the extent to which body size evolution over time can be explained by changes in the physical versus ecological context remains unknown. In this study, we examined body size evolution in ammonoids, an extinct group of marine cephalopods. We collected a representative body size for each genus from illustrated specimens in the Treatise on Invertebrate Paleontology. We then examined relative statistical support for six models of size evolution: random walk, directional trend, stasis, and environmental control by oxygen availability, temperature, and global sea level. No model is unambiguously supported over all others. Unbiased random walk was the best supported model (34%) and environmental control by atmospheric pO2 was the second best supported model (22%). Stasis received the least support (<<1%). Because we find pO2 to be inversely correlated with ammonoid size, we suspect that the observed correlation does not reflect a direct causal relationship. Overall, our results suggest that no single, simple model can be used to characterize the evolution of ammonoid size over the entire history of this clade. We speculate that controls on ammonoid size evolution varied through geological time, both due to long-term shifts in the ecological structure of marine communities and short-term perturbations associated with major extinction events.

  20. A phylogenetic analysis of egg size, clutch size, spawning mode, adult body size, and latitude in reef fishes

    NASA Astrophysics Data System (ADS)

    Kasimatis, Katja; Riginos, Cynthia

    2016-06-01

    Theoretical treatments of egg size in fishes suggest that constraints on reproductive output should create trade-offs between the size and number of eggs produced per spawn. For marine reef fishes, the observation of distinct reproductive care strategies (demersal guarding, egg scattering, and pelagic spawning) has additionally prompted speculation that these strategies reflect alternative fitness optima with selection on egg size differing by reproductive mode and perhaps latitude. Here, we aggregate data from 278 reef fish species and test whether clutch size, reproductive care, adult body size, and latitudinal bands (i.e., tropical, subtropical, and temperate) predict egg size, using a statistically unified framework that accounts for phylogenetic correlations among traits. We find no inverse relationship between species egg size and clutch size, but rather that egg size differs by reproductive mode (mean volume for demersal eggs = 1.22 mm3, scattered eggs = 0.18 mm3, pelagic eggs = 0.52 mm3) and that clutch size is strongly correlated with adult body size. Larger eggs were found in temperate species compared with tropical species in both demersal guarders and pelagic spawners, but this difference was not strong when accounting for phylogenetic correlations, suggesting that differences in species composition underlies regional differences in egg size. In summary, demersal guarders are generally small fishes with small clutch sizes that produce large eggs. Pelagic spawners and egg scatterers are variable in adult and clutch size. Although pelagic spawned eggs are variable in size, those of scatterers are consistently small.

  1. Body size and vocalization in primates and carnivores

    PubMed Central

    Bowling, D. L.; Garcia, M.; Dunn, J. C.; Ruprecht, R.; Stewart, A.; Frommolt, K.-H.; Fitch, W. T.

    2017-01-01

    A fundamental assumption in bioacoustics is that large animals tend to produce vocalizations with lower frequencies than small animals. This inverse relationship between body size and vocalization frequencies is widely considered to be foundational in animal communication, with prominent theories arguing that it played a critical role in the evolution of vocal communication, in both production and perception. A major shortcoming of these theories is that they lack a solid empirical foundation: rigorous comparisons between body size and vocalization frequencies remain scarce, particularly among mammals. We address this issue here in a study of body size and vocalization frequencies conducted across 91 mammalian species, covering most of the size range in the orders Primates (n = 50; ~0.11–120 Kg) and Carnivora (n = 41; ~0.14–250 Kg). We employed a novel procedure designed to capture spectral variability and standardize frequency measurement of vocalization data across species. The results unequivocally demonstrate strong inverse relationships between body size and vocalization frequencies in primates and carnivores, filling a long-standing gap in mammalian bioacoustics and providing an empirical foundation for theories on the adaptive function of call frequency in animal communication. PMID:28117380

  2. Mind/Body Connection: How Your Emotions Affect Your Health

    MedlinePlus

    ... body. Relaxation methods, such as meditation, listening to music, listening to guided imagery CD's or mp3's, yoga, ... Article >>Mental HealthPostpartum Depression (PPD)Postpartum depression affects women after childbirth. It includes feelings of sadness, loneliness, ...

  3. Home ranges, habitat and body mass: simple correlates of home range size in ungulates

    PubMed Central

    Herfindal, Ivar; Solberg, Erling Johan; Sæther, Bernt-Erik

    2016-01-01

    The spatial scale of animal space use, e.g. measured as individual home range size, is a key trait with important implications for ecological and evolutionary processes as well as management and conservation of populations and ecosystems. Explaining variation in home range size has therefore received great attention in ecological research. However, few studies have examined multiple hypotheses simultaneously, which is important provided the complex interactions between life history, social system and behaviour. Here, we review previous studies on home range size in ungulates, supplementing with a meta-analysis, to assess how differences in habitat use and species characteristics affect the relationship between body mass and home range size. Habitat type was the main factor explaining interspecific differences in home range size after accounting for species body mass and group size. Species using open habitats had larger home ranges for a given body mass than species using closed habitats, whereas species in open habitats showed a much weaker allometric relationship compared with species living in closed habitats. We found no support for relationships between home range size and species diet or mating system, or any sexual differences. These patterns suggest that the spatial scale of animal movement mainly is a combined effect of body mass, group size and the landscape structure. Accordingly, landscape management must acknowledge the influence of spatial distribution of habitat types on animal behaviour to ensure natural processes affecting demography and viability of ungulate populations. PMID:28003441

  4. Humans Conceptualize Victory and Defeat in Body Size

    PubMed Central

    Yu, Wenjun; Sun, Zhongqiang; Zhou, Jifan; Xu, Chaoer; Shen, Mowei

    2017-01-01

    Size matters considerably for victory and defeat during competitive situations. Drawing on the embodied theory of cognition, we examined the reciprocal association between size and competition outcomes. To do so, we used the ‘rock-paper-scissors game’, whose outcome is not contingent on apparent physical size. In Experiment 1, participants were asked to judge whether the target gesture was a winning or a losing one. Compared to responses in the incompatible condition (small-winner and large-loser), those in the compatible condition (large-winner and small-loser) were quicker. In Experiment 2, we asked participants to adjust the size of gestures to correspond to gestures previously presented, and found that the winning gesture was estimated as much larger than the losing one. In line with our main hypothesis, size information can interfere with judgments about competition outcomes, and vice versa, even when the outcome is unrelated to body size. PMID:28294145

  5. Affective stimulus properties influence size perception and the Ebbinghaus illusion

    PubMed Central

    Semin, Gün R.; Oudejans, Raôul R. D.; Beek, Peter J.

    2007-01-01

    In the New Look literature of the 1950s, it has been suggested that size judgments are dependent on the affective content of stimuli. This suggestion, however, has been ‘discredited’ due to contradictory findings and methodological problems. In the present study, we revisited this forgotten issue in two experiments. The first experiment investigated the influence of affective content on size perception by examining judgments of the size of target circles with and without affectively loaded (i.e., positive, neutral, and negative) pictures. Circles with a picture were estimated to be smaller than circles without a picture, and circles with a negative picture were estimated to be larger than circles with a positive or a neutral picture confirming the suggestion from the 1950s that size perception is influenced by affective content, an effect notably confined to negatively loaded stimuli. In a second experiment, we examined whether affective content influenced the Ebbinghaus illusion. Participants judged the size of a target circle whereby target and flanker circles differed in affective loading. The results replicated the first experiment. Additionally, the Ebbinghaus illusion was shown to be weakest for a negatively loaded target with positively loaded and blank flankers. A plausible explanation for both sets of experimental findings is that negatively loaded stimuli are more attention demanding than positively loaded or neutral stimuli. PMID:17410379

  6. The Affective Consequences of Minimizing Women's Body Image Concerns

    ERIC Educational Resources Information Center

    Bosson, Jennifer K.; Pinel, Elizabeth C.; Thompson, J. Kevin

    2008-01-01

    We propose that women regularly anticipate and receive messages from others that trivialize the severity of their body image concerns. Moreover, we suggest that these minimizing messages can heighten women's negative affective reactions to body image threats, particularly if they internalize them. Two studies provided support for these ideas. In…

  7. Developmental mechanisms of body size and wing-body scaling in insects.

    PubMed

    Nijhout, H Frederik; Callier, Viviane

    2015-01-07

    The developmental mechanisms that control body size and the relative sizes of body parts are today best understood in insects. Size is controlled by the mechanisms that cause growth to stop when a size characteristic of the species has been achieved. This requires the mechanisms to assess size and respond by stopping the process that controls growth. Growth is controlled by two hormones, insulin and ecdysone, that act synergistically by controlling cell growth and cell division. Ecdysone has two distinct functions: At low concentration it controls growth, and at high levels it causes molting and tissue differentiation. Growth is stopped by the pulse of ecdysone that initiates the metamorphic molt. Body size is sensed by either stretch receptors or oxygen restriction, depending on the species, which stimulate the high level of ecdysone secretion that induces a molt. Wing growth occurs mostly after the body has stopped growing. Wing size is adjusted to body size by variation in both the duration and level of ecdysone secretion.

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

    PubMed Central

    2013-01-01

    Background 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. Results We found sex and age explained the most variance in body mass, condition and length (R2 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 (R2 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 (R2 from 0.01–0.08), while annual rate of landscape change explained additional variance in body length (R2 of 0.03). Human footprint and population density had no observed effect on body size. Conclusions 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

  9. 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

  10. Size matters: relationships between body size and body mass of common coastal, aquatic invertebrates in the Baltic Sea

    PubMed Central

    Austin, Åsa; Bergström, Ulf; Donadi, Serena; Eriksson, Britas D.H.K.; Hansen, Joakim; Sundblad, Göran

    2017-01-01

    Background Organism biomass is one of the most important variables in ecological studies, making biomass estimations one of the most common laboratory tasks. Biomass of small macroinvertebrates is usually estimated as dry mass or ash-free dry mass (hereafter ‘DM’ vs. ‘AFDM’) per sample; a laborious and time consuming process, that often can be speeded up using easily measured and reliable proxy variables like body size or wet (fresh) mass. Another common way of estimating AFDM (one of the most accurate but also time-consuming estimates of biologically active tissue mass) is the use of AFDM/DM ratios as conversion factors. So far, however, these ratios typically ignore the possibility that the relative mass of biologically active vs. non-active support tissue (e.g., protective exoskeleton or shell)—and therefore, also AFDM/DM ratios—may change with body size, as previously shown for taxa like spiders, vertebrates and trees. Methods We collected aquatic, epibenthic macroinvertebrates (>1 mm) in 32 shallow bays along a 360 km stretch of the Swedish coast along the Baltic Sea; one of the largest brackish water bodies on Earth. We then estimated statistical relationships between the body size (length or height in mm), body dry mass and ash-free dry mass for 14 of the most common taxa; five gastropods, three bivalves, three crustaceans and three insect larvae. Finally, we statistically estimated the potential influence of body size on the AFDM/DM ratio per taxon. Results For most taxa, non-linear regression models describing the power relationship between body size and (i) DM and (ii) AFDM fit the data well (as indicated by low SE and high R2). Moreover, for more than half of the taxa studied (including the vast majority of the shelled molluscs), body size had a negative influence on organism AFDM/DM ratios. Discussion The good fit of the modelled power relationships suggests that the constants reported here can be used to quickly estimate organism dry- and

  11. A new explanation for unexpected evolution in body size

    PubMed Central

    2017-01-01

    Bigger is apparently frequently fitter, and body size is typically heritable, so why don’t animals in wild populations evolve towards larger sizes? Different explanations have been proposed for this apparent “paradox of stasis.” A new study of snow voles in the Swiss Alps finds higher survival in animals with larger body mass and heritability of body mass, but, surprisingly, a genetic decline in body mass is also indicated. The authors suggest a novel explanation for this observation: the appearance of positive phenotypic selection is driven by a confounding variable of the age at which a juvenile is measured, whereas the evolutionarily relevant selection actually acts negatively on mass via its association with development time. Thus, genes for larger mass are not actually “fitter” because they are associated with longer development times, and juvenile snow voles with longer development times run the risk of not completing development before the first winter snow. However, the genetic decline in body size is not apparent at the phenotypic level, presumably because of countervailing trends in environmental effects on the phenotype. PMID:28225765

  12. Diabetes Awareness and Body Size Perceptions of Cree Schoolchildren

    ERIC Educational Resources Information Center

    Willows, Noreen D.; Marshall, Dru; Raine, Kim; Ridley, Denise C.

    2009-01-01

    Native American Indians and First Nations are predisposed to obesity and diabetes. A study was done to understand Cree schoolchildren's diabetes awareness and body size perceptions in two communities that had diabetes awareness-raising activities in the Province of Quebec, Canada. Children (N = 203) in grades 4-6 were classified into weight…

  13. Pareto tails and lognormal body of US cities size distribution

    NASA Astrophysics Data System (ADS)

    Luckstead, Jeff; Devadoss, Stephen

    2017-01-01

    We consider a distribution, which consists of lower tail Pareto, lognormal body, and upper tail Pareto, to estimate the size distribution of all US cities. This distribution fits the data more accurately than a distribution that comprises of only lognormal and the upper tail Pareto.

  14. Mass extinctions show selective patterns in crinoid body size

    NASA Astrophysics Data System (ADS)

    Soto, A.; Tang, C.; Pelagio, M.; Heim, N. A.; Payne, J.

    2013-12-01

    There have been five major extinctions on planet Earth: the end of the Ordovician, late Devonian, late Permian, late Triassic and the late Cretaceous and through all of these, Crinoids have still managed to prosper. Our project attempts to find a correlation between these five mass extinctions and the body size of Crinoids. Past research has shown that bigger animals are more prone to extinction compared to smaller sized ones because of their complex environmental niches. We hypothesized that small-sized Crinoids would have a higher possibility of survival compared to the larger-sized Crinoids. We first graphed Crinoids' maximum body size and the five major extinctions throughout time for any visual correlation between them. We then used t-tests as our statistical analyses to find any differences between the size of survivors and. There was no mean difference between the mean size of victims and survivors with the exception of the end of the Triassic extinction. There are many possible explanations for this difference in the end of the Triassic such as 1) a rise in atmospheric CO2, 2) a combination was volcanic CO2 and catastrophic dissociation of gas hydrate, and/or 3) a cooling in temperature and oceanic changes occurred.

  15. Resolving the roles of body size and species identity in driving functional diversity

    PubMed Central

    Rudolf, Volker H. W.; Rasmussen, Nick L.; Dibble, Christopher J.; Van Allen, Benjamin G.

    2014-01-01

    Efforts to characterize food webs have generated two influential approaches that reduce the complexity of natural communities. The traditional approach groups individuals based on their species identity, while recently developed approaches group individuals based on their body size. While each approach has provided important insights, they have largely been used in parallel in different systems. Consequently, it remains unclear how body size and species identity interact, hampering our ability to develop a more holistic framework that integrates both approaches. We address this conceptual gap by developing a framework which describes how both approaches are related to each other, revealing that both approaches share common but untested assumptions about how variation across size classes or species influences differences in ecological interactions among consumers. Using freshwater mesocosms with dragonfly larvae as predators, we then experimentally demonstrate that while body size strongly determined how predators affected communities, these size effects were species specific and frequently nonlinear, violating a key assumption underlying both size- and species-based approaches. Consequently, neither purely species- nor size-based approaches were adequate to predict functional differences among predators. Instead, functional differences emerged from the synergistic effects of body size and species identity. This clearly demonstrates the need to integrate size- and species-based approaches to predict functional diversity within communities. PMID:24598423

  16. Lynx body size in Norway is related to its main prey (Roe deer) density, climate, and latitude.

    PubMed

    Yom-Tov, Yoram; Kvam, Tor; Wiig, Øystein

    2011-02-01

    We studied the effect of various factors on body size variation of the Eurasian lynx in Norway, using data from 374 lynx collected between 1960 and 1976 and whose locality of capture, year of birth, sex, and age were known. Body size of lynx in Norway was mainly affected by sex and age. Female skull size (and by implication body size) was also positively affected by the availability of its main prey (roe deer) and by latitude, and negatively by the North Atlantic Oscillation (NAO). Male size was not affected by any of the environmental factors examined. We interpret the effects of NAO and latitude on body size through their effect on the local climate and particularly snow conditions. We suggest that females are more sensitive to environmental factors than males.

  17. Media influences on body size estimation in anorexia and bulimia. An experimental study.

    PubMed

    Hamilton, K; Waller, G

    1993-06-01

    Anorexic and bulimic women overestimate their body sizes substantially more than comparison women, but little is known about the factors that influence this overestimation. This study examined the influence of media portrayal of idealized female bodies in women's fashion magazines. Comparison women were not affected by the nature of the photographs that they saw, but eating-disordered women were--they overestimated more when they had seen the pictures of women than when they saw photographs of neutral objects.

  18. Phylogenetic analyses of dimorphism in primates: evidence for stronger selection on canine size than on body size.

    PubMed

    Thorén, Sandra; Lindenfors, Patrik; Kappeler, Peter M

    2006-05-01

    Phylogenetic comparative methods were used to analyze the consequences of sexual selection on canine size and canine size dimorphism in primates. Our analyses of previously published body mass and canine size data revealed that the degree of sexual selection is correlated with canine size dimorphism, as well as with canine size in both sexes, in haplorhine but not in strepsirrhine primates. Consistent with these results, male and female canine size was found to be highly correlated in all primates. Since canine dimorphism and canine size in both sexes in haplorhines were found to be not only related to mating system but also to body size and body size dimorphism (characters which are also subject to or the result of sexual selection), it was not apparent whether the degree of canine dimorphism is the result of sexual selection on canine size itself, or whether canine dimorphism is instead a consequence of selection on body size, or vice versa. To distinguish among these possibilities, we conducted matched-pairs analyses on canine size after correcting for the effects of body size. These tests revealed significant effects of sexual selection on relative canine size, indicating that canine size is more important in haplorhine male-male competition than body size. Further analyses showed, however, that it was not possible to detect any evolutionary lag between canine size and body size, or between canine size dimorphism and body size dimorphism. Additional support for the notion of special selection on canine size consisted of allometric relationships in haplorhines between canine size and canine size dimorphism in males, as well as between canine size dimorphism and body size dimorphism. In conclusion, these analyses revealed that the effects of sexual selection on canine size are stronger than those on body size, perhaps indicating that canines are more important than body size in haplorhine male-male competition.

  19. Development and Validation of the Body Size Scale for Assessing Body Weight Perception in African Populations

    PubMed Central

    Cohen, Emmanuel; Bernard, Jonathan Y.; Ponty, Amandine; Ndao, Amadou; Amougou, Norbert; Saïd-Mohamed, Rihlat; Pasquet, Patrick

    2015-01-01

    Background The social valorisation of overweight in African populations could promote high-risk eating behaviours and therefore become a risk factor of obesity. However, existing scales to assess body image are usually not accurate enough to allow comparative studies of body weight perception in different African populations. This study aimed to develop and validate the Body Size Scale (BSS) to estimate African body weight perception. Methods Anthropometric measures of 80 Cameroonians and 81 Senegalese were used to evaluate three criteria of adiposity: body mass index (BMI), overall percentage of fat, and endomorphy (fat component of the somatotype). To develop the BSS, the participants were photographed in full face and profile positions. Models were selected for their representativeness of the wide variability in adiposity with a progressive increase along the scale. Then, for the validation protocol, participants self-administered the BSS to assess self-perceived current body size (CBS), desired body size (DBS) and provide a “body self-satisfaction index.” This protocol included construct validity, test-retest reliability and convergent validity and was carried out with three independent samples of respectively 201, 103 and 1115 Cameroonians. Results The BSS comprises two sex-specific scales of photos of 9 models each, and ordered by increasing adiposity. Most participants were able to correctly order the BSS by increasing adiposity, using three different words to define body size. Test-retest reliability was consistent in estimating CBS, DBS and the “body self-satisfaction index.” The CBS was highly correlated to the objective BMI, and two different indexes assessed with the BSS were consistent with declarations obtained in interviews. Conclusion The BSS is the first scale with photos of real African models taken in both full face and profile and representing a wide and representative variability in adiposity. The validation protocol proved its

  20. Role of media and peers on body change strategies among adult men: is body size important?

    PubMed

    McCabe, Marita P; McGreevy, Shauna J

    2011-01-01

    There has been limited previous research that has examined the role of sociocultural influences on body change strategies among adult men. The current study investigated the role of specific types of messages (encouragement, teasing and modelling) from peers and the media on the strategies to change weight among adult men. Differences were evaluated between 526 men aged from 18 to 60 years from three groups (normal weight, overweight and obese) on body image, body change strategies and messages about their body received from peers and the media. Men were primarily drawn from United States, Australia and Europe. Results showed that messages received by men regarding losing weight or increasing muscle size differed according to weight. Body image and media messages were the strongest predictors of losing weight, whereas body image importance and messages from peers were the strongest predictors of increasing muscles. These findings highlight the importance of sociocultural influences on body change strategies among adult males.

  1. A new model for the body size-metabolism relationship.

    PubMed

    Roberts, Michael F; Lightfoot, Edwin N; Porter, Warren P

    2010-01-01

    The allometric 3/4 power relation, initially used for describing the relation between mammalian basal metabolic rate and body size, is often used as a general model for organismal design. The use of allometric regression as a model has important limitations: it is not mechanistic, it combines all physiological variables into one correlate of body size, and it combines data from several physiological states. In reassessing the use of allometric equations, we first describe problems with their use in studies of organismal design and then use a formulation for distributed net heat production and temperature distribution within the body to derive an alternative equation for the relation between basal metabolism and body size. Tests of the heat flow equation against data reported in the literature indicate that it is an accurate estimator of basal metabolism under thermoneutral conditions and suggest that the allometric equation is a special case of this mechanistic and more general model. We propose that our method is more meaningful and widely applicable for thermoneutral conditions than is a purely allometric approach.

  2. 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.

  3. Prothoracicotropic hormone regulates developmental timing and body size in Drosophila

    PubMed Central

    McBrayer, Zofeyah; Ono, Hajime; Shimell, MaryJane; Parvy, Jean-Philippe; Beckstead, Robert B.; Warren, James T.; Thummel, Carl S.; Dauphin-Villemant, Chantal; Gilbert, Lawrence I.; O’Connor, Michael B.

    2008-01-01

    Summary In insects, control of body size is intimately linked to nutritional quality as well as environmental and genetic cues that regulate the timing of developmental transitions. Prothoracicotropic hormone (PTTH) has been proposed to play an essential role in regulating the production and/or release of ecdysone, a steroid hormone that stimulates molting and metamorphosis. In this report we examine the consequences on Drosophila development of ablating the PTTH-producing neurons. Surprisingly, PTTH production is not essential for molting or metamorphosis. Instead, loss of PTTH results in delayed larval development and eclosion of larger flies with more cells. Prolonged feeding, without changing the rate of growth, causes the developmental delay and is a consequence of low ecdysteroid titers. These results indicate that final body size in insects is determined by a balance between growth rate regulators such as insulin and developmental timing cues such as PTTH that set the duration of the feeding interval. PMID:18061567

  4. Evolution of genetically correlated traits: tooth size and body size in baboons.

    PubMed

    Hlusko, Leslea J; Lease, Loren R; Mahaney, Michael C

    2006-11-01

    Within a population, only phenotypic variation that is influenced by genes will respond to selection. Genes with pleiotropic effects are known to influence numerous traits, complicating our understanding of their evolution through time. Here we use quantitative genetic analyses to identify and estimate the shared genetic effects between molar size and trunk length in a pedigreed, breeding population of baboons housed at the Southwest National Primate Research Center. While crown area has a genetic correlation with trunk length, specific linear measurements yield different results. We find that variation in molar buccolingual width and trunk length is influenced by overlapping additive genetic effects. In contrast, mesiodistal molar length appears to be genetically independent of body size. This is the first study to demonstrate a significant genetic correlation between tooth size and body size in primates. The evolutionary implications are discussed.

  5. Influential sources affecting Bangkok adolescent body image perceptions.

    PubMed

    Thianthai, Chulanee

    2006-01-01

    The study of body image-related problems in non-Western countries is still very limited. Thus, this study aims to identify the main influential sources and show how they affect the body image perceptions of Bangkok adolescents. The researcher recruited 400 Thai male and female adolescents in Bangkok, attending high school to freshmen level, ranging from 16-19 years, to participate in this study. Survey questionnaires were distributed to every student and follow-up interviews conducted with 40 students. The findings showed that there are eight main influential sources respectively ranked from the most influential to the least influential: magazines, television, peer group, familial, fashion trend, the opposite gender, self-realization and health knowledge. Similar to those studies conducted in Western countries, more than half of the total percentage was the influence of mass media and peer groups. Bangkok adolescents also internalized Western ideal beauty through these mass media channels. Alike studies conducted in the West, there was similarities in the process of how these influential sources affect Bangkok adolescent body image perception, with the exception of familial source. In conclusion, taking the approach of identifying the main influential sources and understanding how they affect adolescent body image perceptions can help prevent adolescents from having unhealthy views and taking risky measures toward their bodies. More studies conducted in non-Western countries are needed in order to build a cultural sensitive program, catered to the body image problems occurring in adolescents within that particular society.

  6. Shape and size of the body vs. musculoskeletal stress markers.

    PubMed

    Myszka, Anna; Piontek, Janusz

    2010-01-01

    The objective of this paper is to assess the relationship between the degree of development of muscle attachment sites (musculoskeletal stress markers - MSM1) and the length and circumference measurements of long bones and the body build expressed with the reconstructed values of body height (BH) and body mass (BM). The bone material (102 male and 99 female skeletons) used in the study was collected in the medieval burial ground in Cedynia, Poland. The authors analyzed 10 musculoskeletal stress markers located on the scapula (2), humerus (2), radius (2), femur (2) and tibia (2). The frequency and the degree of expression of muscle attachment size was carried out using the scale prepared by Myszka (2007). The scale encompassed three degrees of expression of muscle attachment size. Only changes of robusticity type (nonpathological changes) were taken into account. The assessment of body build of individuals was carried out according to the method proposed by Vancata & Charvátová (2001). Body height was reconstructed from the length of the humerus and femur using eight equations. Body mass was reconstructed from the measurements of the breadth of the proximal and distal sections of the femur and tibia (mechanical method) using twenty one equations. The equations were developed for different reference populations. The same equations were used for men and women. The correlation between the MSM and the length and circumference measurements of the bones was analyzed using the principal components analysis and the Gamma correlation coefficient. The strength of the correlation between the reconstructed body build traits (BH, BM) and the moderate degree of musculoskeletal stress markers expression was studied based on the principal components method and the Pearson correlation coefficient. A linear correlation was found between musculoskeletal stress markers and the circumference measurements and the reconstructed body mass, but no relationship with body height and the

  7. Relative Importance of Sex, Pre-Starvation Body Mass and Structural Body Size in the Determination of Exceptional Starvation Resistance of Anchomenus dorsalis (Coleoptera: Carabidae)

    PubMed Central

    Knapp, Michal

    2016-01-01

    In nature, almost all animals have to cope with periods of food shortage during their lifetimes. Starvation risks are especially high for carnivorous predatory species, which often experience long intervals between stochastic prey capturing events. A laboratory experiment using the common predatory carabid beetle Anchomenus dorsalis revealed an exceptional level of starvation resistance in this species: males survived up to 137 days and females up to 218 days without food at 20°C. Individual starvation resistance was strongly positively affected by pre-starvation body mass but only slightly by beetle structural body size per se. Females outperformed males even when the effect of gender was corrected for the effects of structural body size and pre-starvation body mass. The better performance of females compared to males and of beetles with higher relative pre-starvation body mass could be linked to higher fat content and lean dry mass before starvation, followed by a greater decrease in both during starvation. There was also a difference between the sexes in the extent of body mass changes both during ad libitum feeding and following starvation; the body masses of females fluctuated more compared to males. This study stresses the need to distinguish between body mass and structural body size when investigating the ecological and evolutionary consequences of body size. Investigation of the net effects of body size and sex is necessary to disentangle the causes of differences in individual performances in studies of species with significant sexual size dimorphism. PMID:26978071

  8. Relative Importance of Sex, Pre-Starvation Body Mass and Structural Body Size in the Determination of Exceptional Starvation Resistance of Anchomenus dorsalis (Coleoptera: Carabidae).

    PubMed

    Knapp, Michal

    2016-01-01

    In nature, almost all animals have to cope with periods of food shortage during their lifetimes. Starvation risks are especially high for carnivorous predatory species, which often experience long intervals between stochastic prey capturing events. A laboratory experiment using the common predatory carabid beetle Anchomenus dorsalis revealed an exceptional level of starvation resistance in this species: males survived up to 137 days and females up to 218 days without food at 20°C. Individual starvation resistance was strongly positively affected by pre-starvation body mass but only slightly by beetle structural body size per se. Females outperformed males even when the effect of gender was corrected for the effects of structural body size and pre-starvation body mass. The better performance of females compared to males and of beetles with higher relative pre-starvation body mass could be linked to higher fat content and lean dry mass before starvation, followed by a greater decrease in both during starvation. There was also a difference between the sexes in the extent of body mass changes both during ad libitum feeding and following starvation; the body masses of females fluctuated more compared to males. This study stresses the need to distinguish between body mass and structural body size when investigating the ecological and evolutionary consequences of body size. Investigation of the net effects of body size and sex is necessary to disentangle the causes of differences in individual performances in studies of species with significant sexual size dimorphism.

  9. Body Size as a Driver of Scavenging in Theropod Dinosaurs.

    PubMed

    Kane, Adam; Healy, Kevin; Ruxton, Graeme D; Jackson, Andrew L

    2016-06-01

    Theropod dinosaurs dominated Earth's terrestrial ecosystem as a diverse group of predators for more than 160 million years, yet little is known about their foraging ecology. Maintaining a balanced energy budget presented a major challenge for therapods, which ranged from the chicken-sized Microraptor up to the whale-sized Giganotosaurus, in the face of intense competition and the demands of ontogenetic growth. Facultative scavenging, a behavior present in almost all modern predators, may have been important in supplementing energetically expensive lifestyles. By using agent-based models based on the allometric relationship between size and foraging behaviors, we show that theropods between 27 and 1,044 kg would have gained a significant energetic advantage over individuals at both the small and large extremes of theropod body mass through their scavenging efficiency. These results were robust to rate of competition, primary productivity, and detection distance. Our models demonstrate the potential importance of facultative scavenging in theropods and the role of body size in defining its prevalence in Mesozoic terrestrial systems.

  10. The evolution of maximum body size of terrestrial mammals.

    PubMed

    Smith, Felisa A; Boyer, Alison G; Brown, James H; Costa, Daniel P; Dayan, Tamar; Ernest, S K Morgan; Evans, Alistair R; Fortelius, Mikael; Gittleman, John L; Hamilton, Marcus J; Harding, Larisa E; Lintulaakso, Kari; Lyons, S Kathleen; McCain, Christy; Okie, Jordan G; Saarinen, Juha J; Sibly, Richard M; Stephens, Patrick R; Theodor, Jessica; Uhen, Mark D

    2010-11-26

    The extinction of dinosaurs at the Cretaceous/Paleogene (K/Pg) boundary was the seminal event that opened the door for the subsequent diversification of terrestrial mammals. Our compilation of maximum body size at the ordinal level by sub-epoch shows a near-exponential increase after the K/Pg. On each continent, the maximum size of mammals leveled off after 40 million years ago and thereafter remained approximately constant. There was remarkable congruence in the rate, trajectory, and upper limit across continents, orders, and trophic guilds, despite differences in geological and climatic history, turnover of lineages, and ecological variation. Our analysis suggests that although the primary driver for the evolution of giant mammals was diversification to fill ecological niches, environmental temperature and land area may have ultimately constrained the maximum size achieved.

  11. Television exposure predicts body size ideals in rural Nicaragua.

    PubMed

    Boothroyd, Lynda G; Jucker, Jean-Luc; Thornborrow, Tracey; Jamieson, Mark A; Burt, D Michael; Barton, Robert A; Evans, Elizabeth H; Tovee, Martin J

    2016-11-01

    Internalization of a thin ideal has been posited as a key risk factor in the development of pathological eating attitudes. Cross-culturally, studies have found a preference for heavier bodies in populations with reduced access to visual media compared to Western populations. As yet, however, there has been little attempt to control for confounding variables in order to isolate the effects of media exposure from other cultural and ecological factors. Here, we examined preferences for female body size in relation to television consumption in Nicaraguan men and women, while controlling for the potential confounding effects of other aspects of Westernization and hunger. We included an urban sample, a sample from a village with established television access, and a sample from a nearby village with very limited television access. The highest BMI preferences were found in the village with least media access, while the lowest BMI preferences were found in the urban sample. Data from the rural sample with established television access were intermediate between the two. Amongst rural women in particular, greater television consumption was a stronger predictor of body weight preferences than acculturation, education, hunger, or income. We also found some evidence for television consumption increasing the likelihood of women seeking to lose weight, possibly via body shape preferences. Overall, these results strongly implicate television access in establishing risk factors for body image disturbances in populations newly gaining access to Western media.

  12. Shrinking body size as an ecological response to climate change

    NASA Astrophysics Data System (ADS)

    Sheridan, Jennifer A.; Bickford, David

    2011-11-01

    Determining how climate change will affect global ecology and ecosystem services is one of the next important frontiers in environmental science. Many species already exhibit smaller sizes as a result of climate change and many others are likely to shrink in response to continued climate change, following fundamental ecological and metabolic rules. This could negatively impact both crop plants and protein sources such as fish that are important for human nutrition. Furthermore, heterogeneity in response is likely to upset ecosystem balances. We discuss future research directions to better understand the trend and help ameliorate the trophic cascades and loss of biodiversity that will probably result from continued decreases in organism size.

  13. Sexual Size Dimorphism and Body Condition in the Australasian Gannet

    PubMed Central

    Angel, Lauren P.; Wells, Melanie R.; Rodríguez-Malagón, Marlenne A.; Tew, Emma; Speakman, John R.; Arnould, John P. Y.

    2015-01-01

    Sexual size dimorphism is widespread throughout seabird taxa and several drivers leading to its evolution have been hypothesised. While the Australasian Gannet (Morus serrator) has previously been considered nominally monomorphic, recent studies have documented sexual segregation in diet and foraging areas, traits often associated with size dimorphism. The present study investigated the sex differences in body mass and structural size of this species at two colonies (Pope’s Eye, PE; Point Danger, PD) in northern Bass Strait, south-eastern Australia. Females were found to be 3.1% and 7.3% heavier (2.74 ± 0.03, n = 92; 2.67 ± 0.03 kg, n = 43) than males (2.66 ± 0.03, n = 92; 2.48 ± 0.03 kg, n = 43) at PE and PD, respectively. Females were also larger in wing ulna length (0.8% both colonies) but smaller in bill depth (PE: 2.2%; PD: 1.7%) than males. Despite this dimorphism, a discriminant function provided only mild accuracy in determining sex. A similar degree of dimorphism was also found within breeding pairs, however assortative mating was not apparent at either colony (R2 < 0.04). Using hydrogen isotope dilution, a body condition index was developed from morphometrics to estimate total body fat (TBF) stores, where TBF(%) = 24.43+1.94*(body mass/wing ulna length) – 0.58*tarsus length (r2 = 0.84, n = 15). This index was used to estimate body composition in all sampled individuals. There was no significant difference in TBF(%) between the sexes for any stage of breeding or in any year of the study at either colony suggesting that, despite a greater body mass, females were not in a better condition than males. While the driving mechanism for sexual dimorphism in this species is currently unknown, studies of other Sulids indicate segregation in foraging behaviour, habitat and diet may be a contributing factor. PMID:26637116

  14. Crater size estimates for large-body terrestrial impact

    NASA Technical Reports Server (NTRS)

    Schmidt, Robert M.; Housen, Kevin R.

    1988-01-01

    Calculating the effects of impacts leading to global catastrophes requires knowledge of the impact process at very large size scales. This information cannot be obtained directly but must be inferred from subscale physical simulations, numerical simulations, and scaling laws. Schmidt and Holsapple presented scaling laws based upon laboratory-scale impact experiments performed on a centrifuge (Schmidt, 1980 and Schmidt and Holsapple, 1980). These experiments were used to develop scaling laws which were among the first to include gravity dependence associated with increasing event size. At that time using the results of experiments in dry sand and in water to provide bounds on crater size, they recognized that more precise bounds on large-body impact crater formation could be obtained with additional centrifuge experiments conducted in other geological media. In that previous work, simple power-law formulae were developed to relate final crater diameter to impactor size and velocity. In addition, Schmidt (1980) and Holsapple and Schmidt (1982) recognized that the energy scaling exponent is not a universal constant but depends upon the target media. Recently, Holsapple and Schmidt (1987) includes results for non-porous materials and provides a basis for estimating crater formation kinematics and final crater size. A revised set of scaling relationships for all crater parameters of interest are presented. These include results for various target media and include the kinematics of formation. Particular attention is given to possible limits brought about by very large impactors.

  15. Exoskeletal chitin scales isometrically with body size in terrestrial insects.

    PubMed

    Lease, Hilary M; Wolf, Blair O

    2010-06-01

    The skeletal system of animals provides the support for a variety of activities and functions. For animals such as mammals, which have endoskeletons, research has shown that skeletal investment (mass) scales with body mass to the 1.1 power. In this study, we ask how exoskeletal investment in insects scales with body mass. We measured the body mass and mass of exoskeletal chitin of 551 adult terrestrial insects of 245 species, with dry masses ranging from 0.0001 to 2.41 g (0.0002-6.13 g wet mass) to assess the allometry of exoskeletal investment. Our results showed that exoskeletal chitin mass scales isometrically with dry body mass across the Insecta as M(chitin) = a M(dry) (b), where b = 1.03 +/- 0.04, indicating that both large and small terrestrial insects allocate a similar fraction of their body mass to chitin. This isometric chitin-scaling relationship was also evident at the taxonomic level of order, for all insect orders except Coleoptera. We additionally found that the relative exoskeletal chitin investment, indexed by the coefficient, a, varies with insect life history and phylogeny. Exoskeletal chitin mass tends to be proportionally less and to increase at a lower rate with mass in flying than in nonflying insects (M(flying insect chitin) = -0.56 x M(dry) (0.97); M(nonflying insect chitin) = -0.55 x M(dry) (1.03)), and to vary with insect order. Isometric scaling (b = 1) of insect exoskeletal chitin suggests that the exoskeleton in insects scales differently than support structures of most other organisms, which have a positive allometry (b > 1) (e.g., vertebrate endoskeleton, tree secondary tissue). The isometric pattern that we document here additionally suggests that exoskeletal investment may not be the primary limit on insect body size.

  16. The scaling of eye size with body mass in birds

    PubMed Central

    Brooke, M. de L.; Hanley, S.; Laughlin, S. B.

    1999-01-01

    We developed a simple method that uses skulls to estimate the diameter, and hence the mass, of birds' eyes. Allometric analysis demonstrated that, within five orders (parrots, pigeons, petrels, raptors and owls) and across 104 families of flying birds, eye mass is proportional to (body mass)0.68 over a range of body masses (6 g to 11.3 kg). As expected from their habits and visual ecology, raptors and owls have enlarged eyes, with masses 1.4 and 2.2 times greater than average birds of the same weight. Taking existing relationships for flight speed on body mass, we find that resolution increases close to (flight speed)1.333. Consequently, large birds resolve objects at a longer time to contact than small birds. Eye radius and skull size co-vary in strict proportion, suggesting common physiological, aerodynamic and mechanical constraints. Because eye mass scales close to brain mass, metabolic rate and information processing could also be limiting, but the precise factors determining the scaling of eye to body have not been identified.

  17. Big people, little world: the body influences size perception.

    PubMed

    Stefanucci, Jeanine K; Geuss, Michael N

    2009-01-01

    Previous research has shown that changes to the body can influence the perception of distances in near space (Witt et al, 2005 Journal of Experimental Psychology: Human Perception and Performance 31 880-888). In this paper, we question whether changes to the body can also influence the perception of extents in extrapersonal space, namely the perception of aperture widths. In experiment 1, broad-shouldered participants visually estimated the size of apertures to be smaller than narrow-shouldered participants. In experiment 2, we questioned whether changes to the body, which included holding a large object, wearing a large object, or simply holding out the arms would influence perceived width. Surprisingly, we found that only when participants' hands were widened was extrapersonal space rescaled. In experiment 3, we explored the boundaries of the effect observed in experiment 2 by asking participants to hold their arms at four different positions in order to determine the arm width at which apertures appeared smaller. We found that arm positions that were larger than the shoulder width made apertures appear smaller. The results suggest that dimensions of the body play a role in the scaling of environmental parameters in extrapersonal space.

  18. The evolution of body armor in mammals: plantigrade constraints of large body size.

    PubMed

    Lovegrove, B G

    2001-07-01

    Predictions associated with opposing selection generating minimum variance in basal metabolic rate (BMR) in mammals at a constrained body mass (CBM; 358 g) were tested. The CBM is presumed to be associated with energetic constraints linked to predation and variable resources at intermediate sizes on a logarithmic mass scale. Opposing selection is thought to occur in response to energetic constraints associated with predation and unpredictable resources. As body size approaches and exceeds the CBM, mammals face increasing risks of predation and daily energy requirements. Fast running speeds may require high BMRs, but unpredictable and low resources may select for low BMRs, which also reduce foraging time and distances and thus predation risks. If these two selection forces oppose each other persistently, minimum BMR variance may result. However, extreme BMR outliers at and close to the CBM should be indicative of unbalanced selection and predator avoidance alternatives (escapers vs. defenders), and may therefore provide indirect support for opposing selection. It was confirmed that body armor in defenders evolves at and above the CBM, and armored mammals had significantly lower BMRs than their nonarmored counterparts. However, analyses comparing the BMR of escapers--the fastest nonarmored runners (Lagomorpha)--with similar-sized counterparts were inconclusive and were confounded by limb morphology associated with speed optimization. These analyses suggest that the risks and costs of predation and the speed limitations of the plantigrade foot may constrain the evolution of large body sizes in plantigrade mammals.

  19. Size matters: plasticity in metabolic scaling shows body-size may modulate responses to climate change

    PubMed Central

    Carey, Nicholas; Sigwart, Julia D.

    2014-01-01

    Variability in metabolic scaling in animals, the relationship between metabolic rate (R) and body mass (M), has been a source of debate and controversy for decades. R is proportional to Mb, the precise value of b much debated, but historically considered equal in all organisms. Recent metabolic theory, however, predicts b to vary among species with ecology and metabolic level, and may also vary within species under different abiotic conditions. Under climate change, most species will experience increased temperatures, and marine organisms will experience the additional stressor of decreased seawater pH (‘ocean acidification’). Responses to these environmental changes are modulated by myriad species-specific factors. Body-size is a fundamental biological parameter, but its modulating role is relatively unexplored. Here, we show that changes to metabolic scaling reveal asymmetric responses to stressors across body-size ranges; b is systematically decreased under increasing temperature in three grazing molluscs, indicating smaller individuals were more responsive to warming. Larger individuals were, however, more responsive to reduced seawater pH in low temperatures. These alterations to the allometry of metabolism highlight abiotic control of metabolic scaling, and indicate that responses to climate warming and ocean acidification may be modulated by body-size. PMID:25122741

  20. Size matters: plasticity in metabolic scaling shows body-size may modulate responses to climate change.

    PubMed

    Carey, Nicholas; Sigwart, Julia D

    2014-08-01

    Variability in metabolic scaling in animals, the relationship between metabolic rate ( R: ) and body mass ( M: ), has been a source of debate and controversy for decades. R: is proportional to MB: , the precise value of B: much debated, but historically considered equal in all organisms. Recent metabolic theory, however, predicts B: to vary among species with ecology and metabolic level, and may also vary within species under different abiotic conditions. Under climate change, most species will experience increased temperatures, and marine organisms will experience the additional stressor of decreased seawater pH ('ocean acidification'). Responses to these environmental changes are modulated by myriad species-specific factors. Body-size is a fundamental biological parameter, but its modulating role is relatively unexplored. Here, we show that changes to metabolic scaling reveal asymmetric responses to stressors across body-size ranges; B: is systematically decreased under increasing temperature in three grazing molluscs, indicating smaller individuals were more responsive to warming. Larger individuals were, however, more responsive to reduced seawater pH in low temperatures. These alterations to the allometry of metabolism highlight abiotic control of metabolic scaling, and indicate that responses to climate warming and ocean acidification may be modulated by body-size.

  1. Effects of body size and temperature on population growth.

    PubMed

    Savage, Van M; Gilloly, James F; Brown, James H; Charnov, Eric L

    2004-03-01

    For at least 200 years, since the time of Malthus, population growth has been recognized as providing a critical link between the performance of individual organisms and the ecology and evolution of species. We present a theory that shows how the intrinsic rate of exponential population growth, rmax, and the carrying capacity, K, depend on individual metabolic rate and resource supply rate. To do this, we construct equations for the metabolic rates of entire populations by summing over individuals, and then we combine these population-level equations with Malthusian growth. Thus, the theory makes explicit the relationship between rates of resource supply in the environment and rates of production of new biomass and individuals. These individual-level and population-level processes are inextricably linked because metabolism sets both the demand for environmental resources and the resource allocation to survival, growth, and reproduction. We use the theory to make explicit how and why rmax exhibits its characteristic dependence on body size and temperature. Data for aerobic eukaryotes, including algae, protists, insects, zooplankton, fishes, and mammals, support these predicted scalings for rmax. The metabolic flux of energy and materials also dictates that the carrying capacity or equilibrium density of populations should decrease with increasing body size and increasing temperature. Finally, we argue that body mass and body temperature, through their effects on metabolic rate, can explain most of the variation in fecundity and mortality rates. Data for marine fishes in the field support these predictions for instantaneous rates of mortality. This theory links the rates of metabolism and resource use of individuals to life-history attributes and population dynamics for a broad assortment of organisms, from unicellular organisms to mammals.

  2. Body size correlates with fertilization success but not gonad size in grass goby territorial males.

    PubMed

    Pujolar, Jose Martin; Locatello, Lisa; Zane, Lorenzo; Mazzoldi, Carlotta

    2012-01-01

    In fish species with alternative male mating tactics, sperm competition typically occurs when small males that are unsuccessful in direct contests steal fertilization opportunities from large dominant males. In the grass goby Zosterisessor ophiocephalus, large territorial males defend and court females from nest sites, while small sneaker males obtain matings by sneaking into nests. Parentage assignment of 688 eggs from 8 different nests sampled in the 2003-2004 breeding season revealed a high level of sperm competition. Fertilization success of territorial males was very high but in all nests sneakers also contributed to the progeny. In territorial males, fertilization success correlated positively with male body size. Gonadal investment was explored in a sample of 126 grass gobies collected during the period 1995-1996 in the same area (61 territorial males and 65 sneakers). Correlation between body weight and testis weight was positive and significant for sneaker males, while correlation was virtually equal to zero in territorial males. That body size in territorial males is correlated with fertilization success but not gonad size suggests that males allocate much more energy into growth and relatively little into sperm production once the needed size to become territorial is attained. The increased paternity of larger territorial males might be due to a more effective defense of the nest in comparison with smaller territorial males.

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

    PubMed Central

    Brandl, Simon J.

    2016-01-01

    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. PMID:28083093

  4. Methodology significantly affects genome size estimates: quantitative evidence using bryophytes.

    PubMed

    Bainard, Jillian D; Fazekas, Aron J; Newmaster, Steven G

    2010-08-01

    Flow cytometry (FCM) is commonly used to determine plant genome size estimates. Methodology has improved and changed during the past three decades, and researchers are encouraged to optimize protocols for their specific application. However, this step is typically omitted or undescribed in the current plant genome size literature, and this omission could have serious consequences for the genome size estimates obtained. Using four bryophyte species (Brachythecium velutinum, Fissidens taxifolius, Hedwigia ciliata, and Thuidium minutulum), three methodological approaches to the use of FCM in plant genome size estimation were tested. These included nine different buffers (Baranyi's, de Laat's, Galbraith's, General Purpose, LB01, MgSO(4), Otto's, Tris.MgCl(2), and Woody Plant), seven propidium iodide (PI) staining periods (5, 10, 15, 20, 45, 60, and 120 min), and six PI concentrations (10, 25, 50, 100, 150, and 200 microg ml(-1)). Buffer, staining period and staining concentration all had a statistically significant effect (P = 0.05) on the genome size estimates obtained for all four species. Buffer choice and PI concentration had the greatest effect, altering the 1C-values by as much as 8% and 14%, respectively. As well, the quality of the data varied with the different methodology used. Using the methodology determined to be the most accurate in this study (LB01 buffer and PI staining for 20 min at 150 microg ml(-1)), three new genome size estimates were obtained: B. velutinum: 0.46 pg, H. ciliata: 0.30 pg, and T. minutulum: 0.46 pg. While the peak quality of flow cytometry histograms is important, researchers must consider that changes in methodology can also affect the relative peak positions and therefore the genome size estimates obtained for plants using FCM.

  5. Relationships between Body Size and Parasitic Fitness and Offspring Performance of Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae)

    PubMed Central

    Gao, Shangkun; Tang, Yanlong; Wei, Ke; Wang, Xiaoyi; Yang, Zhongqi; Zhang, Yanlong

    2016-01-01

    The relationship between body size and fitness in parasitoid wasps has several effects on parasitic ability, reproductive behavior in female wasps, and progeny fitness. Female wasps with various body sizes were obtained by mass–rearing a gregarious ectoparasitoid, Sclerodermus pupariae, which is one of the excellent parasites to control the larvae and pupae of Buprestidae and Cerambycidae. We investigated the effects of body size of adult females introduced on Thyestilla gebleri (Coleoptera: Cerambycidae) larvae on their paralysis time, pre–oviposition period, oviposition period and fecundity, and the related fitness of their offspring. Results showed that small female wasps needed more time to paralyze a host and had a higher mortality rate than large female wasps. More offspring were produced by large female wasps than by small female wasps, and the percentage and body size of female offspring was not affected by maternal body size. The duration of the egg stage was not affected by foundress size, nor was that of the pupal stage, but the duration of the larval stage and generation time of small female wasps was longer than that of large females. Our findings suggest that the parasitic fitness and offspring performance are affected by maternal size, and there is need to choose reasonable body size of female wasps, to optimally utilize mass rearing and to control target pests with the lowest mortality cost. PMID:27367523

  6. 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.

  7. Size heterogeneity of epidermal growth factor in human body fluids

    SciTech Connect

    Pesonen, K.; Viinikka, L.; Koskimies, A.; Banks, A.R.; Nicolson, M.; Perheentupa, J.

    1987-06-29

    The authors measured the concentration of immunoreactive (IR) hEGF in various body fluids by radioimmunoassay (RIA) and evaluated its size heterogeneity by size exclusion high performance liquid chromatography combined with RIA or with time-resolved immunofluorometric assay (TR-IFMA). Mean concentration was 80 ng/ml in urine, 65 ng/ml in milk, 50 ng/ml in seminal plasma, 25 ng/ml in armpit sweat, 1 ng/ml in breast sweat, 0.3 ng/ml in third-trimester amniotic fluid, 3 ng/ml in saliva, 1.5 ng/ml in tears and 0.3 ng/ml in gastric juice. All the fluids except armpit sweat and gastric juice contained two to five molecular sizes of IR-hEGF. As well as the 6200-dalton (6.2kDa) hEGF the authors found at least four other different molecular sizes with approximate weights of greater than or equal to300, 150, 70 and 20 kDa. The authentic 6.2kDa form made up >90% of the total IR-hEGF in all except the amniotic fluid where its proportion was 71%, and the seminal plasma where the proportion could not be determined. 18 references, 1 figure, 1 table.

  8. Relationship between regolith particle size and porosity on small bodies

    NASA Astrophysics Data System (ADS)

    Kiuchi, M.; Nakamura, A.

    2014-07-01

    Small planetary bodies are covered by a particle layer called the regolith. The particle size and porosity of the regolith surface of the small bodies are important physical properties. The responses of the surface to solar irradiation depend on the particle size and porosity. The particle size and porosity have influences on the dynamic responses of the surface, such as cratering efficiency. In previous studies, these two quantities were measured or estimated by various methods. Here we propose a semi-empirical relationship between the particle size and porosity for small bodies' surfaces. An empirical relationship between the porosity of granular materials in loose packing state under 1G and the ratio of the magnitudes of the interparticle force and gravity which act on a particle was presented in a previous study [1]. In this study, we assume that the van der Waals force F_{V} is predominant in the interparticle forces and adopt a model formula [2] which is different from that adopted in the previous study [1]: F_{V} = {AS^{2}}/{48Ω ^{2}}r, where A is the Hamaker constant, r is the particle radius, Ω is the diameter of an O^{-2} ion, and S is the cleanliness ratio which shows the smallness of a number of the adsorbate molecules [2]. It was shown that the cleanliness ratio S is approximately 0.1 on the Earth, and is almost unity in the interplanetary space. In addition to the data of the several previous studies, our own measurement result for micron-sized fly-ash particles in atmospheric conditions is used in the present analysis. We calculate F_{V} using Eq. (1), and obtain a relationship between porosity and the ratio R_{F} = F_{V}/F_{g}, where F_{g} is gravity. An empirical formula used in the previous study [1], p = p_{0}+(1-p_{0})exp(-m{R_{F}}^{-n}), is applied to fit the data, where p is the porosity and p_{0}, m and n are constants. We assume that p_{0} is 0.36. By substituting Eq. (1) to Eq. 2, we obtain p = p_{0}+(1-p_{0})exp {-m({AS^{2}}/{64πΩ ^{2

  9. 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.

  10. 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.

  11. The elite athlete - assessing body shape, size, proportion and composition.

    PubMed

    Kerr, D A; Ackland, T R; Schreiner, A B

    1995-03-01

    In the quest to optimize performance of the elite athlete the sport scientist has sought to determine the ideal physique for a given sport or event. For some sports, specific structural characteristics offer definite performance advantages; for example in rowing, in addition to height, a large arm span has been identified as important. In other sports. such as long distance running, low levels of adiposity or 'fatness' appear to be linked with faster running times. There are four areas where appraisal of the athlete's physique can provide useful information: (1) identification of talented athletes; (2) to assess and monitor the growing athlete; (3) to monitor training and performance; and (4) to determine 'race weight' in weight-category sports. As a research tool a particular method must be reliable and valid. Other considerations include how expensive the method is, if it is suitable for a field situation and if large amounts of data on a number of subjects can be collected quickly. The method should be safe for both the athlete and the tester and provide useful feedback for the athlete or coach. Anthropometry, with training is able to fulfil most of these criteria and is the most widely used method of physique assessment in sports science. Large anthropometric data bases have been collected on elite athletes at Olympic games and world championships according to a standard protocol. Kinanthropometry, which has developed from anthropometry, is concerned with measurement and evaluation of different aspects of human movement and individual variation in body shape, size, proportion and composition. For the assessment of adiposity a sum of skinfolds, usually over six sites, is most commonly used rather than percentage body fat formulae. Muscle mass can be assessed indirectly through girth and corrected girth measurements. Limb lengths and breadths are used to assess skeletal structure and proportional differences in limb size. The anthropometric methods most commonly

  12. Body size and body shape in early hominins - implications of the Gona pelvis.

    PubMed

    Ruff, Christopher

    2010-02-01

    Discovery of the first complete Early Pleistocene hominin pelvis, Gona BSN49/P27, attributed to Homo erectus, raises a number of issues regarding early hominin body size and shape variation. Here, acetabular breadth, femoral head breadth, and body mass calculated from femoral head breadth are compared in 37 early hominin (6.0-0.26 Ma) specimens, including BSN49/P27. Acetabular and estimated femoral head sizes in the Gona specimen fall close to the means for non-Homo specimens (Orrorin tugenesis, Australopithecus africanus, Paranthropus robustus), and well below the ranges of all previously described Early and Middle Pleistocene Homo specimens. The Gona specimen has an estimated body mass of 33.2kg, close to the mean for the non-Homo sample (34.1kg, range 24-51.5kg, n=19) and far outside the range for any previously known Homo specimen (mean=70.5kg; range 52-82kg, n=17). Inclusion of the Gona specimen within H. erectus increases inferred sexual dimorphism in body mass in this taxon to a level greater than that observed here for any other hominin taxon, and increases variation in body mass within H. erectus females to a level much greater than that observed for any living primate species. This raises questions regarding the taxonomic attribution of the Gona specimen. When considered within the context of overall variation in body breadth among early hominins, the mediolaterally very wide Gona pelvis fits within the distribution of other lower latitude Early and Middle Pleistocene specimens, and below that of higher latitude specimens. Thus, ecogeographic variation in body breadth was present among earlier hominins as it is in living humans. The increased M-L pelvic breadth in all earlier hominins relative to modern humans is related to an increase in ellipticity of the birth canal, possibly as a result of a non-rotational birth mechanism that was common to both australopithecines and archaic Homo.

  13. 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

  14. Offspring size at weaning affects survival to recruitment and reproductive performance of primiparous gray seals

    PubMed Central

    Bowen, William D; den Heyer, Cornelia E; McMillan, Jim I; Iverson, Sara J

    2015-01-01

    Offspring size affects survival and subsequent reproduction in many organisms. However, studies of offspring size in large mammals are often limited to effects on juveniles because of the difficulty of following individuals to maturity. We used data from a long-term study of individually marked gray seals (Halichoerus grypus; Fabricius, 1791) to test the hypothesis that larger offspring have higher survival to recruitment and are larger and more successful primiparous mothers than smaller offspring. Between 1998 and 2002, 1182 newly weaned female pups were branded with unique permanent marks on Sable Island, Canada. Each year through 2012, all branded females returning to the breeding colony were identified in weekly censuses and a subset were captured and measured. Females that survived were significantly longer offspring than those not sighted, indicating size-selective mortality between weaning and recruitment. The probability of female survival to recruitment varied among cohorts and increased nonlinearly with body mass at weaning. Beyond 51.5 kg (mean population weaning mass) weaning mass did not influence the probability of survival. The probability of female survival to recruitment increased monotonically with body length at weaning. Body length at primiparity was positively related to her body length and mass at weaning. Three-day postpartum mass (proxy for birth mass) of firstborn pups was also positively related to body length of females when they were weaned. However, females that were longer or heavier when they were weaned did not wean heavier firstborn offspring. PMID:25897381

  15. Effect of environmental variables on body size evolution of crinoids between periods of mass extinctions

    NASA Astrophysics Data System (ADS)

    Jani, T.; Heim, N. A.; Payne, J.

    2013-12-01

    Body size plays a major role in determining whether or not an organism can sustain in its local environment. The ecosystem of an animal has a major effect on the fitness of organisms, and it would be interesting to note the degree to which various environmental factors alter body size. In my project, I identify three environmental factors that seem to affect body size of crinoids, marine invertebrates from phylum Echinodermata, and explore how these variables play out in the intervals between the five mass extinctions. The particular factors I study include atmospheric CO2 concentration (proxy for temperature), O2 concentration, and sea level. Although the r and p values for all of these factors were statistically insignificant to definitively make any correlation, there was a visual correlation. For O2, I noted a generally positive correlation with body size over time. CO2 trends suggested a negative correlation until the K-T boundary, but a positive correlation afterwards. Correlation with sea level was a little more complicated: correlation was positive from the start of the Phanerozoic to the Permian extinction; it turned negative until the Cretaceous-Tertiary boundary; afterwards, it again became positive. However, for all three variables, statistical values are too low to say definitively mark any correlation. Out of all three factors, CO2 levels had the highest correlation and lowest p-values in the most time intervals: from the start of the Phanerozoic to Ordovician-Silurian Extinction, from the Late Devonian to the Permian Extinction, and from the Cretaceous-Tertiary boundary to the present. When considering first differences, CO2 levels also had the highest correlation from the Permian Extinction to Triassic-Jurassic Extinction and from the Triassic-Jurassic Extinction to Cretaceous-Tertiary Extinction. Using PaleoTS, I found that body size evolution patterns either seemed to follow either an unbiased random walk (URW) or stasis in the intervals between

  16. 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

  17. Specific dynamic action of ambystomatid salamanders and the effects of meal size, meal type, and body temperature.

    PubMed

    Secor, Stephen M; Boehm, Matthew

    2006-01-01

    The past decade has witnessed a dramatic increase in studies of amphibian and reptile specific dynamic action (SDA). These studies have demonstrated that SDA, the summed energy expended on meal digestion and assimilation, is affected significantly by meal size, meal type, and body size and to some extent by body temperature. While much of this attention has been directed at anuran and reptile SDA, we investigated the effects of meal size, meal type, and body temperature on the postprandial metabolic responses and the SDA of the tiger salamander (Ambystoma tigrinum tigrinum). We also compared the SDA responses among six species of Ambystoma salamanders representing the breadth of Ambystoma phylogeny. Postprandial peaks in VO(2) and VO(2), duration of elevated metabolism, and SDA of tiger salamanders increased with the size of cricket meals (2.5%-12.5% of body mass). For A. tigrinum, as for other ectotherms, a doubling of meal size results in an approximate doubling of SDA, a function of equal increases in peak VO(2) and duration. For nine meal types of equivalent size (5% of body mass), the digestion of hard-bodied prey (crickets, superworms, mealworms, beetles) generated larger SDA responses than the digestion of soft-bodied prey (redworms, beetle larvae). Body temperature affected the profile of postprandial metabolism, increasing the peak and shortening the duration of the profile as body temperature increased. SDA was equivalent among three body temperatures (20 degrees, 25 degrees, and 30 degrees C) but decreased significantly at 15 degrees C. Comparatively, the postprandial metabolic responses and SDA of Ambystoma jeffersonianum, Ambystoma maculatum, Ambystoma opacum, Ambystoma talpoideum, Ambystoma texanum, and the conspecific Ambystoma tigrinum mavortium digesting cricket meals that were 5% of their body mass were similar (independent of body mass) to those of A. t. tigrinum. Among the six species, standard metabolic rate, peak postprandial VO(2), and SDA

  18. Rate of language evolution is affected by population size.

    PubMed

    Bromham, Lindell; Hua, Xia; Fitzpatrick, Thomas G; Greenhill, Simon J

    2015-02-17

    The effect of population size on patterns and rates of language evolution is controversial. Do languages with larger speaker populations change faster due to a greater capacity for innovation, or do smaller populations change faster due to more efficient diffusion of innovations? Do smaller populations suffer greater loss of language elements through founder effects or drift, or do languages with more speakers lose features due to a process of simplification? Revealing the influence of population size on the tempo and mode of language evolution not only will clarify underlying mechanisms of language change but also has practical implications for the way that language data are used to reconstruct the history of human cultures. Here, we provide, to our knowledge, the first empirical, statistically robust test of the influence of population size on rates of language evolution, controlling for the evolutionary history of the populations and formally comparing the fit of different models of language evolution. We compare rates of gain and loss of cognate words for basic vocabulary in Polynesian languages, an ideal test case with a well-defined history. We demonstrate that larger populations have higher rates of gain of new words whereas smaller populations have higher rates of word loss. These results show that demographic factors can influence rates of language evolution and that rates of gain and loss are affected differently. These findings are strikingly consistent with general predictions of evolutionary models.

  19. 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

  20. Visual Diet versus Associative Learning as Mechanisms of Change in Body Size Preferences

    PubMed Central

    Boothroyd, Lynda G.; Tovée, Martin J.; Pollet, Thomas V.

    2012-01-01

    Systematic differences between populations in their preferences for body size may arise as a result of an adaptive ‘prepared learning’ mechanism, whereby cues to health or status in the local population are internalized and affect body preferences. Alternatively, differences between populations may reflect their ‘visual diet’ as a cognitive byproduct of mere exposure. Here we test the relative importance of these two explanations for variation in body preferences. Two studies were conducted where female observers were exposed to pictures of high or low BMI women which were either aspirational (healthy, attractive models in high status clothes) or non-aspirational (eating disordered patients in grey leotards), or to combinations thereof, in order to manipulate their body-weight preferences which were tested at baseline and at post–test. Overall, results showed good support for visual diet effects (seeing a string of small or large bodies resulted in a change from pre- to post-test whether the bodies were aspirational or not) and also some support for the associative learning explanation (exposure to aspirational images of overweight women induced a towards preferring larger bodies, even when accompanied by equal exposure to lower weight bodies in the non-aspirational category). Thus, both influences may act in parallel. PMID:23144929

  1. Computing Gravitational Fields of Finite-Sized Bodies

    NASA Technical Reports Server (NTRS)

    Quadrelli, Marco

    2005-01-01

    A computer program utilizes the classical theory of gravitation, implemented by means of the finite-element method, to calculate the near gravitational fields of bodies of arbitrary size, shape, and mass distribution. The program was developed for application to a spacecraft and to floating proof masses and associated equipment carried by the spacecraft for detecting gravitational waves. The program can calculate steady or time-dependent gravitational forces, moments, and gradients thereof. Bodies external to a proof mass can be moving around the proof mass and/or deformed under thermoelastic loads. An arbitrarily shaped proof mass is represented by a collection of parallelepiped elements. The gravitational force and moment acting on each parallelepiped element of a proof mass, including those attributable to the self-gravitational field of the proof mass, are computed exactly from the closed-form equation for the gravitational potential of a parallelepiped. The gravitational field of an arbitrary distribution of mass external to a proof mass can be calculated either by summing the fields of suitably many point masses or by higher-order Gauss-Legendre integration over all elements surrounding the proof mass that are part of a finite-element mesh. This computer program is compatible with more general finite-element codes, such as NASTRAN, because it is configured to read a generic input data file, containing the detailed description of the finiteelement mesh.

  2. 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.

  3. 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.

  4. 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

  5. Rapid body size decline in Alaskan Pleistocene horses before extinction.

    PubMed

    Guthrie, R Dale

    2003-11-13

    About 70% of North American large mammal species were lost at the end of the Pleistocene epoch. The causes of this extinction--the role of humans versus that of climate--have been the focus of much controversy. Horses have figured centrally in that debate, because equid species dominated North American late Pleistocene faunas in terms of abundance, geographical distribution, and species variety, yet none survived into the Holocene epoch. The timing of these equid regional extinctions and accompanying evolutionary changes are poorly known. In an attempt to document better the decline and demise of two Alaskan Pleistocene equids, I selected a large number of fossils from the latest Pleistocene for radiocarbon dating. Here I show that horses underwent a rapid decline in body size before extinction, and I propose that the size decline and subsequent regional extinction at 12,500 radiocarbon years before present are best attributed to a coincident climatic/vegetational shift. The present data do not support human overkill and several other proposed extinction causes, and also show that large mammal species responded somewhat individualistically to climate changes at the end of the Pleistocene.

  6. Patterns of Diversity in Soft-Bodied Meiofauna: Dispersal Ability and Body Size Matter

    PubMed Central

    Curini-Galletti, Marco; Artois, Tom; Delogu, Valentina; De Smet, Willem H.; Fontaneto, Diego; Jondelius, Ulf; Leasi, Francesca; Martínez, Alejandro; Meyer-Wachsmuth, Inga; Nilsson, Karin Sara; Tongiorgi, Paolo; Worsaae, Katrine; Todaro, M. Antonio

    2012-01-01

    Background Biogeographical and macroecological principles are derived from patterns of distribution in large organisms, whereas microscopic ones have often been considered uninteresting, because of their supposed wide distribution. Here, after reporting the results of an intensive faunistic survey of marine microscopic animals (meiofauna) in Northern Sardinia, we test for the effect of body size, dispersal ability, and habitat features on the patterns of distribution of several groups. Methodology/Principal Findings As a dataset we use the results of a workshop held at La Maddalena (Sardinia, Italy) in September 2010, aimed at studying selected taxa of soft-bodied meiofauna (Acoela, Annelida, Gastrotricha, Nemertodermatida, Platyhelminthes and Rotifera), in conjunction with data on the same taxa obtained during a previous workshop hosted at Tjärnö (Western Sweden) in September 2007. Using linear mixed effects models and model averaging while accounting for sampling bias and potential pseudoreplication, we found evidence that: (1) meiofaunal groups with more restricted distribution are the ones with low dispersal potential; (2) meiofaunal groups with higher probability of finding new species for science are the ones with low dispersal potential; (3) the proportion of the global species pool of each meiofaunal group present in each area at the regional scale is negatively related to body size, and positively related to their occurrence in the endobenthic habitat. Conclusion/Significance Our macroecological analysis of meiofauna, in the framework of the ubiquity hypothesis for microscopic organisms, indicates that not only body size but mostly dispersal ability and also occurrence in the endobenthic habitat are important correlates of diversity for these understudied animals, with different importance at different spatial scales. Furthermore, since the Western Mediterranean is one of the best-studied areas in the world, the large number of undescribed species (37

  7. Optimizing human embryonic stem cells differentiation efficiency by screening size-tunable homogenous embryoid bodies.

    PubMed

    Moon, Sung-Hwan; Ju, Jongil; Park, Soon-Jung; Bae, Daekyeong; Chung, Hyung-Min; Lee, Sang-Hoon

    2014-07-01

    Human embryonic stem cells (hESCs) are generally induced to differentiate by forming spherical structures termed embryoid bodies (EBs) in the presence of soluble growth factors. hEBs are generated by suspending small clumps of hESC colonies; however, the resulting hEBs are heterogeneous because this method lacks the ability to control the number of cells in individual EBs. This heterogeneity affects factors that influence differentiation such as cell-cell contact and the diffusion of soluble factors, and consequently, the differentiation capacity of each EB varies. Here, we fabricated size-tunable concave microwells to control the physical environment, thereby regulating the size of EBs formed from single hESCs. Defined numbers of single hESCs were forced to aggregate and generate uniformly sized EBs with high fidelity, and the size of the EBs was controlled using concave microwells of different diameters. Differentiation patterns in H9- and CHA15-hESCs were affected by EB size in both the absence and presence of growth factors. By screening EB size in the presence of various BMP4 concentrations, a two-fold increase in endothelial cell differentiation was achieved. Because each hESC line has unique characteristics, the findings of this study demonstrate that concave microwells could be used to screen different EB sizes and growth factor concentrations to optimize differentiation for each hESC line.

  8. Scaling of sexual dimorphism in body weight and canine size in primates.

    PubMed

    Leutenegger, W

    1982-01-01

    Among primates sexual dimorphism in both body weight and canine size increases exponentially with increasing body size. This suggests that a full explanation of the variance in sexual dimorphism can only be attained if, in addition to sexual selection, parental investment, and various ecological factors, the influence of body size is taken into account. Positive allometry in both body weight dimorphism and canine size dimorphism is demonstrated to be associated with polygyny. In monogamous species the two dimorphisms not only remain constant throughout the size range but actually are minimal or lacking at any given body size.

  9. Quantitative trait loci for honey bee stinging behavior and body size.

    PubMed Central

    Hunt, G J; Guzmán-Novoa, E; Fondrk, M K; Page, R E

    1998-01-01

    A study was conducted to identify quantitative trait loci (QTLs) that affect colony-level stinging behavior and individual body size of honey bees. An F1 queen was produced from a cross between a queen of European origin and a drone descended from an African subspecies. Haploid drones from the hybrid queen were individually backcrossed to sister European queens to produce 172 colonies with backcross workers that were evaluated for tendency to sting. Random amplified polymorphic DNA markers were scored from the haploid drone fathers of these colonies. Wings of workers and drones were used as a measure of body size because Africanized bees in the Americas are smaller than European bees. Standard interval mapping and multiple QTL models were used to analyze data. One possible QTL was identified with a significant effect on tendency to sting (LOD 3.57). Four other suggestive QTLs were also observed (about LOD 1.5). Possible QTLs also were identified that affect body size and were unlinked to defensive-behavior QTLs. Two of these were significant (LOD 3.54 and 5.15). PMID:9539435

  10. Chemical Variations Affect Seismic Velocities Less Than Grain Size Variations

    NASA Astrophysics Data System (ADS)

    de Jong, B. H.; Jacobs, M. H.

    2001-12-01

    It is well known that mantle velocities depend on the ``Magnesium number'' of constituent minerals. According to our recently developed equation of state (Jacobs & Oonk, Calphad 24, 133--147, 2000) this speed varies almost linearly between 6.7422 (Mg2SiO4) and 6.0113 (Fe2SiO4) km/sec at 10 GPa and 1500 K, i.e. a velocity contrast of 730 m/sec, the canonical mantle composition at 400 km depth being 52% Mg2SiO4 in accordance with the estimates by Lee et al. (1998). We have shown experimentally elsewhere that grain size variations of isochemical, equal density, holocrystalline alkali disilicates affect acoustic velocities. These vary at room temperature and ambient pressure between 6.6 km/sec (coarse grained) and 7.7 km/sec (fine grained), a difference of 1100 m/sec, i.e. substantially larger than the above mentioned 730 m/sec for chemical variations. Such differences in grain size occur because of variations in time, temperature, transformation (TTT) conditions to which a material is subjected. Thus velocity variations as observed in the mantle do not necessarily reflect current hottter or colder localities or compositional variations. They more likely reflect different TTT conditions with concomitant fabric variation during subduction.

  11. 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…

  12. Influence of geography and climate on patterns of cell size and body size in the lizard Anolis carolinensis.

    PubMed

    Goodman, Rachel M; Echternacht, Arthur C; Hall, Jim C; Deng, Lihan D; Welch, Jessica N

    2013-06-01

    Geographic patterns in body size are often associated with latitude, elevation, or environmental and climatic variables. This study investigated patterns of body size and cell size of the green anole lizard, Anolis carolinensis, and potential associations with geography or climatic variables. Lizards were sampled from 19 populations across the native range, and body size, red blood cell size and size and number of muscle cells were measured. Climatic data from local weather stations and latitude and longitude were entered into model selection with Akaike's information criterion to explain patterns in cell and body sizes. Climatic variables did not drive any major patterns in cell size or body size; rather, latitude and longitude were the best predictors of cell and body size. In general, smaller body and cell sizes in Florida anoles drove geographic patterns in A. carolinensis. Small size in Florida may be attributable to the geological history of the peninsular state or the unique ecological factors in this area, including a recently introduced congener. In contrast to previous studies, we found that A. carolinensis does not follow Bergmann's rule when the influence of Florida is excluded. Rather, the opposite pattern of larger lizards in southern populations is evident in the absence of Florida populations, and mirrors the general pattern in squamates. Muscle cell size was negatively related to latitude and red blood cell size showed no latitudinal trend outside of Florida. Different patterns in the sizes of the 2 cell types confirm the importance of examining multiple cell types when studying geographic variation in cell size.

  13. Seasonal shifts in predator body size diversity and trophic interactions in size-structured predator-prey systems.

    PubMed

    Rudolf, Volker H W

    2012-05-01

    1. Theory suggests that the relationship between predator diversity and prey suppression should depend on variation in predator traits such as body size, which strongly influences the type and strength of species interactions. Prey species often face a range of different sized predators, and the composition of body sizes of predators can vary between communities and within communities across seasons. 2. Here, I test how variation in size structure of predator communities influences prey survival using seasonal changes in the size structure of a cannibalistic population as a model system. Laboratory and field experiments showed that although the per-capita consumption rates increased at higher predator-prey size ratios, mortality rates did not consistently increase with average size of cannibalistic predators. Instead, prey mortality peaked at the highest level of predator body size diversity. 3. Furthermore, observed prey mortality was significantly higher than predictions from the null model that assumed no indirect interactions between predator size classes, indicating that different sized predators were not substitutable but had more than additive effects. Higher predator body size diversity therefore increased prey mortality, despite the increased potential for behavioural interference and predation among predators demonstrated in additional laboratory experiments. 4. Thus, seasonal changes in the distribution of predator body sizes altered the strength of prey suppression not only through changes in mean predator size but also through changes in the size distribution of predators. In general, this indicates that variation (i.e. diversity) within a single trait, body size, can influence the strength of trophic interactions and emphasizes the importance of seasonal shifts in size structure of natural food webs for community dynamics.

  14. Bumblebee flight performance in cluttered environments: effects of obstacle orientation, body size and acceleration.

    PubMed

    Crall, James D; Ravi, Sridhar; Mountcastle, Andrew M; Combes, Stacey A

    2015-09-01

    Locomotion through structurally complex environments is fundamental to the life history of most flying animals, and the costs associated with movement through clutter have important consequences for the ecology and evolution of volant taxa. However, few studies have directly investigated how flying animals navigate through cluttered environments, or examined which aspects of flight performance are most critical for this challenging task. Here, we examined how body size, acceleration and obstacle orientation affect the flight of bumblebees in an artificial, cluttered environment. Non-steady flight performance is often predicted to decrease with body size, as a result of a presumed reduction in acceleration capacity, but few empirical tests of this hypothesis have been performed in flying animals. We found that increased body size is associated with impaired flight performance (specifically transit time) in cluttered environments, but not with decreased peak accelerations. In addition, previous studies have shown that flying insects can produce higher accelerations along the lateral body axis, suggesting that if maneuvering is constrained by acceleration capacity, insects should perform better when maneuvering around objects laterally rather than vertically. Our data show that bumblebees do generate higher accelerations in the lateral direction, but we found no difference in their ability to pass through obstacle courses requiring lateral versus vertical maneuvering. In sum, our results suggest that acceleration capacity is not a primary determinant of flight performance in clutter, as is often assumed. Rather than being driven by the scaling of acceleration, we show that the reduced flight performance of larger bees in cluttered environments is driven by the allometry of both path sinuosity and mean flight speed. Specifically, differences in collision-avoidance behavior underlie much of the variation in flight performance across body size, with larger bees

  15. Impact of a healthy body image program among adolescent boys on body image, negative affect, and body change strategies.

    PubMed

    McCabe, Marita P; Ricciardelli, Lina A; Karantzas, Gery

    2010-03-01

    This study evaluated the effectiveness of a healthy body image program. In total, 421 adolescent boys completed a five-session intervention program or a wait list control group. There were no differences between the intervention and the control group at post-intervention or any of the follow-up times. Boys in the intervention group who were one standard deviation above the mean on body dissatisfaction at baseline, demonstrated a reduction in negative affect in the intervention group at post-test and 6 months follow-up. Prevention programs need to target boys who are at risk of adopting health risk behaviors, rather than being universally applied.

  16. Examining predator-prey body size, trophic level and body mass across marine and terrestrial mammals.

    PubMed

    Tucker, Marlee A; Rogers, Tracey L

    2014-12-22

    Predator-prey relationships and trophic levels are indicators of community structure, and are important for monitoring ecosystem changes. Mammals colonized the marine environment on seven separate occasions, which resulted in differences in species' physiology, morphology and behaviour. It is likely that these changes have had a major effect upon predator-prey relationships and trophic position; however, the effect of environment is yet to be clarified. We compiled a dataset, based on the literature, to explore the relationship between body mass, trophic level and predator-prey ratio across terrestrial (n = 51) and marine (n = 56) mammals. We did not find the expected positive relationship between trophic level and body mass, but we did find that marine carnivores sit 1.3 trophic levels higher than terrestrial carnivores. Also, marine mammals are largely carnivorous and have significantly larger predator-prey ratios compared with their terrestrial counterparts. We propose that primary productivity, and its availability, is important for mammalian trophic structure and body size. Also, energy flow and community structure in the marine environment are influenced by differences in energy efficiency and increased food web stability. Enhancing our knowledge of feeding ecology in mammals has the potential to provide insights into the structure and functioning of marine and terrestrial communities.

  17. 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.

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

    PubMed

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

    2011-08-23

    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.

  19. Dietary calcium intake, body size, and body composition in the Training Intervention and Genetics of Exercise Response study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased calcium intake has been associated with lower body weight, body mass index (BMI), and adiposity measures in cross-sectional studies, as well as randomized clinical trials. However, much of the research on dietary calcium and body size to date has focused only on Caucasian, middle-aged men ...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Implant Size Availability Affects Reproduction of Distal Femoral Anatomy.

    PubMed

    Morris, William Z; Gebhart, Jeremy J; Goldberg, Victor M; Wera, Glenn D

    2016-07-01

    A total knee arthroplasty system offers more distal femoral implant anterior-posterior (AP) sizes than its predecessor. The purpose of this study is to investigate the impact of increased size availability on an implant system's ability to reproduce the AP dimension of the native distal femur. We measured 200 cadaveric femora with the AP-sizing guides of Zimmer (Warsaw, IN) NexGen (8 sizes) and Zimmer Persona (12 sizes) total knee arthroplasty systems. We defined "size deviation" as the difference in the AP dimension between the anatomic size of the native femur and the closest implant size. We defined satisfactory reproduction of distal femoral dimensions as < 1 mm difference between the implant and native femur size. The NexGen system was associated with a mean 0.46 mm greater implant size deviation than Persona (p < 0.001). When using a 1 mm size deviation as a cutoff for satisfactory replication of the native distal femoral anatomy, 85/200 specimens (42.5%) were a poor fit by NexGen, but a satisfactory fit by Persona. Only 1/200 specimens (0.5%) was a poor fit by Persona, but a satisfactory fit by NexGen (p < 0.001). The novel knee system with 12 versus 8 sizes reproduces the AP dimension of the native distal femur more closely than its predecessor. Further study is needed to determine the clinical impact of these differences.

  5. 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.

  6. 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

  7. Common Noctule Bats Are Sexually Dimorphic in Migratory Behaviour and Body Size but Not Wing Shape

    PubMed Central

    O’Mara, M. Teague; Bauer, Karla; Blank, Dominik; Baldwin, Justin W.; Dechmann, Dina K. N.

    2016-01-01

    Within the large order of bats, sexual size dimorphism measured by forearm length and body mass is often female-biased. Several studies have explained this through the effects on load carrying during pregnancy, intrasexual competition, as well as the fecundity and thermoregulation advantages of increased female body size. We hypothesized that wing shape should differ along with size and be under variable selection pressure in a species where there are large differences in flight behaviour. We tested whether load carrying, sex differential migration, or reproductive advantages of large females affect size and wing shape dimorphism in the common noctule (Nyctalus noctula), in which females are typically larger than males and only females migrate long distances each year. We tested for univariate and multivariate size and shape dimorphism using data sets derived from wing photos and biometric data collected during pre-migratory spring captures in Switzerland. Females had forearms that are on average 1% longer than males and are 1% heavier than males after emerging from hibernation, but we found no sex differences in other size, shape, or other functional characters in any wing parameters during this pre-migratory period. Female-biased size dimorphism without wing shape differences indicates that reproductive advantages of big mothers are most likely responsible for sexual dimorphism in this species, not load compensation or shape differences favouring aerodynamic efficiency during pregnancy or migration. Despite large behavioural and ecological sex differences, morphology associated with a specialized feeding niche may limit potential dimorphism in narrow-winged bats such as common noctules and the dramatic differences in migratory behaviour may then be accomplished through plasticity in wing kinematics. PMID:27880791

  8. The influence of body size, condition index and tidal exposure on the variability in metal bioaccumulation in Mytilus edulis.

    PubMed

    Mubiana, Valentine K; Vercauteren, Kathleen; Blust, Ronny

    2006-11-01

    Mussels are commonly used to monitor metal pollution despite high inter-individual variability in tissue concentrations. In this study, influences of body size, condition index and tidal height on concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were investigated. Body weight was inversely related to metal concentrations and for Cd, Mn, Pb and Zn the regression was affected by tidal height. Except for As, Fe and Mn metal concentrations were inversely related to physiological status though no differences between essential and non-essential metals were obvious. After correcting for body size, tidal height was related positively to As, Cd and Zn, negatively related to Cu, Fe and Mn while Co, Cr, Ni and Pb were independent of tidal height. The study recommends stringent measures during sampling for biomonitoring or metal concentrations at each location must be normalized to a common body size, CI and tidal height.

  9. Correlation of tooth size and body size in living hominoid primates, with a note on relative brain size in Aegyptopithecus and Proconsul.

    PubMed

    Gingerich, P D

    1977-11-01

    Second molar length and body weight are used to test the correlation between tooth size and body size in living Hominoidea. These variates are highly correlated (r= 0.942, p less than 0.001), indicating that tooth size can be used in dentally unspecialized fossil hominoids as one method of predicting the average body weight of species. Based on tooth size, the average body weight of Aegyptopithecus zeuxis is estimated to have been beteen 4.5 and 7.5 kg, which is corroborated by known cranial and postcranial elements. Using Radinsky's estimates of brain size, the encephalization quotient (EQ) for Aegyptopithecus was between 0.65 and 1.04. A similar analysis for Proconsul africanus yields a body weight between 16 and 34 kg, and an EQ between 1.19 and 1.96.

  10. Phylogenetic evidence for competitively driven divergence: body-size evolution in Caribbean treefrogs (Hylidae: Osteopilus).

    PubMed

    Moen, Daniel S; Wiens, John J

    2009-01-01

    Understanding the role of competition in explaining phenotypic diversity is a challenging problem, given that the most divergent species may no longer compete today. However, convergent evolution of extreme body sizes across communities may offer evidence of past competition. For example, many treefrog assemblages around the world have convergently evolved species with very large and small body sizes. To better understand this global pattern, we studied body-size diversification within the small, endemic radiation of Caribbean treefrogs (Osteopilus). We introduce a suite of analyses designed to help reveal the signature of past competition. Diet analyses show that Osteopilus are generalist predators and that prey size is strongly associated with body size, suggesting that body-size divergence facilitates resource partitioning. Community assembly models indicate that treefrog body-size distributions in Jamaica and Hispaniola are consistent with expectations from competition. Phylogenetic analyses show that similar body-size extremes in Jamaica and Hispaniola have originated through parallel evolution on each island, and the rate of body-size evolution in Osteopilus is accelerated relative to mainland treefrogs. Together, these results suggest that competition may have driven the rapid diversification of body sizes in Caribbean treefrogs to the extremes seen in treefrog communities around the world.

  11. 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.

  12. Body size as a predictor of species loss effect on ecosystem functioning

    PubMed Central

    Séguin, Annie; Harvey, Éric; Archambault, Philippe; Nozais, Christian; Gravel, Dominique

    2014-01-01

    There is an urgent need to develop predictive indicators of the effect of species loss on ecosystem functioning. Body size is often considered as a good indicator because of its relationship to extinction risk and several functional traits. Here, we examined the predictive capacity of species body size in marine and freshwater multitrophic systems. We found a significant, but weak, effect of body size on functioning. The effect was much stronger when considering the effect of body size within trophic position levels. Compared to extinctions ordered by body size, random extinction sequences had lower multiple species loss effects on functioning. Our study is the first to show experimentally, in multitrophic systems, a more negative impact of ordered extinction sequences on ecosystem functioning than random losses. Our results suggest apparent ease in predicting species loss effect on functioning based on easily measured ecological traits that are body size and trophic position. PMID:24714619

  13. Body size as a predictor of species loss effect on ecosystem functioning.

    PubMed

    Séguin, Annie; Harvey, Éric; Archambault, Philippe; Nozais, Christian; Gravel, Dominique

    2014-04-09

    There is an urgent need to develop predictive indicators of the effect of species loss on ecosystem functioning. Body size is often considered as a good indicator because of its relationship to extinction risk and several functional traits. Here, we examined the predictive capacity of species body size in marine and freshwater multitrophic systems. We found a significant, but weak, effect of body size on functioning. The effect was much stronger when considering the effect of body size within trophic position levels. Compared to extinctions ordered by body size, random extinction sequences had lower multiple species loss effects on functioning. Our study is the first to show experimentally, in multitrophic systems, a more negative impact of ordered extinction sequences on ecosystem functioning than random losses. Our results suggest apparent ease in predicting species loss effect on functioning based on easily measured ecological traits that are body size and trophic position.

  14. How Methodological Features Affect Effect Sizes in Education

    ERIC Educational Resources Information Center

    Cheung, Alan; Slavin, Robert

    2016-01-01

    As evidence-based reform becomes increasingly important in educational policy, it is becoming essential to understand how research design might contribute to reported effect sizes in experiments evaluating educational programs. The purpose of this study was to examine how methodological features such as types of publication, sample sizes, and…

  15. Size counts: evolutionary perspectives on physical activity and body size from early hominids to modern humans.

    PubMed

    Leonard, William R

    2010-11-01

    This paper examines the evolutionary origins of human dietary and activity patterns, and their implications for understanding modern health problems. Humans have evolved distinctive nutritional characteristics associated the high metabolic costs of our large brains. The evolution of larger hominid brain size necessitated the adoption of foraging strategies that both provided high quality foods, and required larger ranges and activity budgets. Over time, human subsistence strategies have become ever more efficient in obtaining energy with minimal time and effort. Today, populations of the industrialized world live in environments characterized by low levels of energy expenditure and abundant food supplies contributing to growing rates of obesity. Analyses of trends in dietary intake and body weight in the US over the last 50 years indicate that the dramatic rise in obesity cannot be explained solely by increased energy consumption. Rather, declines in activity are also important. Further, we find that recent recommendations on physical activity have the potential to bring daily energy expenditure levels of industrialized societies surprisingly close to those observed among subsistence-level populations. These findings highlight the importance of physical activity in promoting nutritional health and show the utility of evolutionary approaches for developing public health recommendations.

  16. The evolution of body size in extant groups of North American freshwater fishes: speciation, size distributions, and Cope's rule.

    PubMed

    Knouft, Jason H; Page, Lawrence M

    2003-03-01

    Change in body size within an evolutionary lineage over time has been under investigation since the synthesis of Cope's rule, which suggested that there is a tendency for mammals to evolve larger body size. Data from the fossil record have subsequently been examined for several other taxonomic groups to determine whether they also displayed an evolutionary increase in body size. However, we are not aware of any species-level study that has investigated the evolution of body size within an extant continental group. Data acquired from the fossil record and data derived from the evolutionary relationships of extant species are not similar, with each set exhibiting both strengths and weaknesses related to inferring evolutionary patterns. Consequently, expectation that general trends exhibited in the fossil record will correspond to patterns in extant groups is not necessarily warranted. Using phylogenetic relationships of extant species, we show that five of nine families of North American freshwater fishes exhibit an evolutionary trend of decreasing body size. These trends result from the basal position of large species and the more derived position of small species within families. Such trends may be caused by the invasion of small streams and subsequent isolation and speciation. This pattern, potentially influenced by size-biased dispersal rates and the high percentage of small streams in North America, suggests a scenario that could result in the generation of the size-frequency distribution of North American freshwater fishes.

  17. The Effect of Abiotic Factors on Marine Animal Body Size Evolution

    NASA Astrophysics Data System (ADS)

    Wang, X. F.; Wong, W.; Heim, N.; Payne, J.

    2015-12-01

    While there is evidence of a general increase in body size over time, there has been no comprehensive attempt to determine the influence of abiotic factors on body size. Although an increase in maximum body size has been observed during and after the Precambrian oxidation events in the Late Archean and at the onset of the Cambrian, these observations took into account the appearance of eukaryotic life and multicellular life respectively. Using a database of marine animal body sizes spanning the Phanerozoic, we conducted a series of Pearson product-moment correlation tests with igneous rock weathering (Strontium-87: Strontium-86), rate of carbon cycle (δ13C), temperature (δ18O), CO2 concentration, sulfate mineral weathering (δ34S), atmospheric oxygen concentration, and sea level as independent variables, and mean body size as the dependent variable. Our test yielded a correlation coefficient of 0.81 between δ18O and body size, and -0.78 between rCO2 and body size; since δ18O is inversely correlated with temperature, these results indicate that both temperature and CO2 have strong inverse relationships with body size. Atmospheric oxygen yielded a correlation coefficient of 0.09, demonstrating that it ceased to play an influential role in shaping body sizes following the start of the Phanerozoic.

  18. 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'.

  19. Estimating body size in early primates: The case of Archicebus and Teilhardina.

    PubMed

    Dagosto, Marian; Gebo, Daniel; Ni, Xijun; Smith, Thierry

    2017-03-19

    Obtaining accurate estimations of the body mass of fossil primates has always been a subject of interest in paleoanthropology because mass is an important determinant for so many other aspects of biology, ecology, and life history. This paper focuses on the issues involved in attempting to reconstruct the mass of two early Eocene haplorhine primates, Teilhardina and Archicebus, which pose particular problems due to their small size and temporal and phylogenetic distance from extant primates. In addition to a ranking of variables from more to less useful, the effect of using models of varying taxonomic and size compositions is examined. Phylogenetic correction is also applied to the primate database. Our results indicate that the choice of variable is more critical than the choice of model. The more reliable variables are the mediolateral breadth across the femoral condyles and the area of the calcaneocuboid facet of the calcaneus. These variables suggest a body mass of 39 g (range 33-46 g) for Archicebus and 48 g (range 44-56 g) for Teilhardina. The width of the distal femur is found to be the most consistent estimator across models of various composition and techniques. The effect of phylogenetic correction is small but the choice of branch length assumption affects point estimates for the fossils. The majority of variables and models predict the body mass of Archicebus and Teilhardina to be in the range of the smaller extant mouse lemurs, as expected.

  20. BODY IMAGE AMONG MEN WHO PRACTICE BODY BUILDING: COMPARISON BY AGE, ECONOMIC STATUS, AND CITY SIZE.

    PubMed

    Silva, Diego A S; Da Silva, Rafael C; Gonçalves, Eliane C A

    2015-10-01

    Identifying the factors that influence the body image of body builders is important for understanding this construct. The aim of this study was to analyze the association between body image and age, socioeconomic status, and place of residence of body builders from two cities in Brazil. A cross-sectional study of 301 body builders with an average age of 25.2 yr. (SD = 3.5) was carried out. The Muscle Silhouette Measure scale was used, in which the discrepancy between current and desired silhouette was examined. Older body builders showed greater discrepancy between current and desired silhouette, reflecting their desire for a more muscular body.

  1. 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.

  2. Does Body Mass Index Affect Mortality in Coronary Surgery?

    PubMed Central

    Protopapas, Aristotle D.

    2016-01-01

    Introduction: The Body Mass Index (BMI) quantifies nutritional status and classifies humans as underweight, of normal weight, overweight, mildly obese, moderately obese or morbidly obese. Obesity is the excessive accumulation of fat, defined as BMI higher than 30 kg/m2. Obesity is widely accepted to complicate anaesthesia and surgery, being a risk factor for mediastinitis after coronary artery bypass grafting (CABG). We sought the evidence on operative mortality of CABG between standard BMI groups. Materials and Methodology: A simple literature review of papers presenting the mortality of CABG by BMI group: Underweight (BMI ≤ 18.49 kg/m2), normal weight (BMI 18.5–24.9 kg/m2), overweight (BMI 25.0–29.9 kg/m2), mild obesity (BMI 30.0–34.9 kg/m2), moderate obesity (BMI 35.0–39.9 kg/m2), or morbid obesity (BMI ≥ 40.0 kg/m2). Results: We identified 18 relevant studies with 1,027,711 patients in total. Their variability in size of samples and choice of BMI groups precluded us from attempting inferential statistics. The overall cumulative mortality was 2.7%. Underweight patients had by far the highest mortality (6.6%). Overweight patients had the lowest group mortality (2.1%). The group mortality for morbidly obese patients was 3.44%. Discussion: Patients with extreme BMI’s undergoing CABG (underweight ones more than morbidly obese) suffer increased crude mortality. This simple observation indicates that under nutrition and morbid obesity need be further explored as risk factors for coronary surgery. PMID:28217179

  3. Geographical variations in adult body size and reproductive life history traits in an invasive anuran, Discoglossus pictus.

    PubMed

    Oromi, Neus; Pujol-Buxó, Eudald; San Sebastián, Olatz; Llorente, Gustavo A; Hammou, Mohamed Aït; Sanuy, Delfi

    2016-06-01

    Variability in life history traits positively affects the establishment and expansive potential of invasive species. In the present study, we analysed the variation of body size in seven populations - two native and five invasive - of the painted frog (Discoglossus pictus, Anura: Discoglossidae), native to North Africa and introduced in southern France and the north-east of the Iberian Peninsula. Other life history traits (age at maturity, size at maturity, longevity, median age and potential reproductive lifespan) were analysed in a native and an invasive population. We observed geographic variations in adult body size, related mainly to mean annual precipitation. Thus, populations had greater body size as mean annual precipitation increased, resulting in bigger specimens in the invasive populations. Adult body size and growth rates also varied between sexes in all studied populations, with males significantly larger than females. Age distribution varied between native (1-5 years) and invasive populations (2-4 years) and also between sexes. Our results suggest that higher precipitation promotes faster growth rates and larger adult body size that could facilitate the successful establishment of invasive populations.

  4. Impact of variable body size on pedestrian dynamics by heuristics-based model

    NASA Astrophysics Data System (ADS)

    Guo, Ning; Hu, Mao-Bin; Jiang, Rui

    2017-01-01

    In the real world, pedestrians can arch the shoulders or rotate their bodies actively to across the narrow space. The method is helpful to reduce the effective size of the body. In this paper, the impact of variable body size on the direction choice has been investigated by an improved heuristic-based model. In the model, it is assumed that the cost of adjusting body size is a factor in the process to evaluate the optimal direction. In a typical simulation scenario, the pedestrian reluctant to adjust body size will pass by the blocks. On the contrary, the pedestrian caring little about body size will traverse through the exit. There is a direction-choice change behavior between bypass and traverse considering block width and the initial location of the pedestrian.

  5. 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

  6. Island colonisation and the evolutionary rates of body size in insular neonate snakes.

    PubMed

    Aubret, F

    2015-10-01

    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.

  7. 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

  8. The evolution of mammal body sizes: responses to Cenozoic climate change in North American mammals.

    PubMed

    Lovegrove, B G; Mowoe, M O

    2013-06-01

    Explanations for the evolution of body size in mammals have remained surprisingly elusive despite the central importance of body size in evolutionary biology. Here, we present a model which argues that the body sizes of Nearctic mammals were moulded by Cenozoic climate and vegetation changes. Following the early Eocene Climate Optimum, forests retreated and gave way to open woodland and savannah landscapes, followed later by grasslands. Many herbivores that radiated in these new landscapes underwent a switch from browsing to grazing associated with increased unguligrade cursoriality and body size, the latter driven by the energetics and constraints of cellulose digestion (fermentation). Carnivores also increased in size and digitigrade, cursorial capacity to occupy a size distribution allowing the capture of prey of the widest range of body sizes. With the emergence of larger, faster carnivores, plantigrade mammals were constrained from evolving to large body sizes and most remained smaller than 1 kg throughout the middle Cenozoic. We find no consistent support for either Cope's Rule or Bergmann's Rule in plantigrade mammals, the largest locomotor guild (n = 1186, 59% of species in the database). Some cold-specialist plantigrade mammals, such as beavers and marmots, showed dramatic increases in body mass following the Miocene Climate Optimum which may, however, be partially explained by Bergmann's rule. This study reemphasizes the necessity of considering the evolutionary history and resultant form and function of mammalian morphotypes when attempting to understand contemporary mammalian body size distributions.

  9. Climate change and shrinking salamanders: alternative mechanisms for changes in plethodontid salamander body size.

    PubMed

    Connette, Grant M; Crawford, John A; Peterman, William E

    2015-08-01

    An increasing number of studies have demonstrated relationships between climate trends and body size change of organisms. In many cases, climate might be expected to influence body size by altering thermoregulation, energetics or food availability. However, observed body size change can result from a variety of ecological processes (e.g. growth, selection, population dynamics) or imperfect observation of biological systems. We used two extensive datasets to evaluate alternative mechanisms for recently reported changes in the observed body size of plethodontid salamanders. We found that mean adult body size of salamanders can be highly sensitive to survey conditions, particularly rainfall. This systematic bias in the detection of larger or smaller individuals could result in a signature of body size change in relation to reported climate trends when it is simply observation error. We also identify considerable variability in body size distributions among years and find that individual growth rates can be strongly influenced by weather. Finally, our study demonstrates that measures of mean adult body size can be highly variable among surveys and that large sample sizes may be required to make reliable inferences. Identifying the effects of climate change is a critical area of research in ecology and conservation. Researchers should be aware that observed changes in certain organisms can result from multiple ecological processes or systematic bias due to nonrandom sampling of populations.

  10. Drinking spout orifice size affects licking behavior in inbred mice.

    PubMed

    Dotson, Cedrick D; Spector, Alan C

    2005-08-07

    Using a lickometer, we assessed the effect of drinking spout orifice size on the licking behavior of inbred mice [C57BL/6J, SWR/J, 129P3/J and DBA/2J]. Animals licked from drinking spout sipper tubes that had what were defined as either a large (2.7 mm) or a small (1.5 mm) orifice. Mice took approximately twice as many licks from a stationary single small orifice drinking spout than when licking from a spout with a large orifice during separate 30-min sessions. However, their total intake volume was approximately the same. We calculated that mice received a mean of 0.55 muL per lick from the drinking tubes with a small orifice and a mean of 1.15 muL per lick from the drinking tubes with a large orifice. Thus, the animals appear to have regulated their fluid intake by proportionally adjusting their licking as a function of the lick volume. On average, this regulation occurred through modulation of the size of licking bursts and not their frequency. However, strain differences in compensation strategy were observed. When licking was restricted to a series of 5-s trials in a 30-min brief access test session, the smaller orifice size increased the range of responsiveness that was expressed. Mice increased their average licks per trial by 20% and took 60% more trials when licking from a spout with a small orifice. Interestingly, when the orifice size was quasi-randomly varied within a brief access session, licking was greater from large orifice drinking spouts, suggesting that water delivered from the two orifice sizes differs in its reinforcement efficacy. These findings demonstrate that drinking spout orifice size can significantly influence experimental outcomes in licking tests involving mice and care should be taken in controlling this variable in testing the effects of taste or other factors on ingestive behavior.

  11. Somatotype, size and body composition of competitive female volleyball players.

    PubMed

    Malousaris, Grigoris G; Bergeles, Nikolaos K; Barzouka, Karolina G; Bayios, Ioannis A; Nassis, George P; Koskolou, Maria D

    2008-06-01

    The aim of this study was to describe the morphological characteristics of competitive female volleyball players. For this purpose, body weight and height, breadths and girths as well as skinfold thickness at various body sites were assessed in 163 elite female volleyball players (age: 23.8+/-4.7 years, years of playing: 11.5+/-4.2, hours of training per week: 11.9+/-2.9, means+/-S.D.). Seventy-nine of these players were from the A1 division and the rest from the A2 division of the Greek National League. Two-way ANOVA was used to compare the differences in these characteristics between competition level and playing position. Body height ranged from 161cm to 194cm, and the mean value (177.1+/-6.5cm) was not inferior to that of international players of similar calibre. Adiposity of these players (sum of 5 skinfolds: 51.8+/-10.2mm, percent body fat: 23.4+/-2.8) was higher than that reported in other studies in which, however, different methodology was used. Volleyball athletes of this study were mainly balanced endomorphs (3.4-2.7-2.9). The A1 division players were taller and slightly leaner with greater fat-free mass than their A2 counterparts. Significant differences were found among athletes of different playing positions which are interpreted by their varying roles and physical demands during a volleyball game. The volleyball players who play as opposites were the only subgroup of players differing between divisions; the A2 opposites had more body fat than A1 opposites. These data could be added in the international literature related to the anthropometric characteristics of competitive female volleyball players.

  12. How Methodological Features Affect Effect Sizes in Education

    ERIC Educational Resources Information Center

    Cheung, Alan C. K.; Slavin, Robert E.

    2016-01-01

    As evidence becomes increasingly important in educational policy, it is essential to understand how research design might contribute to reported effect sizes in experiments evaluating educational programs. A total of 645 studies from 12 recent reviews of evaluations of preschool, reading, mathematics, and science programs were studied. Effect…

  13. Radish (Raphanus sativus) seed size affects germination response to coumarin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The inhibition of seed germination by an allelochemical is generally greater in small seeds than in large seeds. Studies reporting these results used a large number of plant species that varied in seed size, which might have introduced differences in germination characteristics or various parameter...

  14. Dissociations between the horizontal and dorsoventral axes in body-size perception

    PubMed Central

    Hashimoto, Teruo; Iriki, Atsushi

    2013-01-01

    Body size can vary throughout a person's lifetime, inducing plasticity of the internal body representation. Changes in horizontal width accompany those in dorsal-to-ventral thickness. To examine differences in the perception of different body axes, neural correlates of own-body-size perception in the horizontal and dorsoventral directions were compared using functional magnetic resonance imaging. Original and distorted (−30, −10, +10 and +30%) images of the neck-down region of their own body were presented to healthy female participants, who were then asked whether the images were of their own body or not based explicitly on body size. Participants perceived body images distorted by −10% as their own, whereas those distorted by +30% as belonging to others. Horizontal width images yielded slightly more subjective own-body perceptions than dorsoventral thickness images did. Subjective perception of own-body size was associated with bilateral inferior parietal activity. In contrast, other-body judgments showed pre-supplementary motor and superior parietal activity. Expansion in the dorsoventral direction was associated with the left fusiform gyrus and the right inferior parietal lobule, whereas horizontal expansions were associated with activity in the bilateral somatosensory area. These results suggest neural dissociations between the two body axes: dorsoventral images of thickness may require visual processing, whereas bodily sensations are involved in horizontal body-size perception. Somatosensory rather than visual processes can be critical for the assessment of frontal own-body appearance. Visual body thickness and somatosensory body width may be integrated to construct a whole-body representation. PMID:23510226

  15. 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.

  16. Cope's rule and the evolution of body size in Pinnipedimorpha (Mammalia: Carnivora).

    PubMed

    Churchill, Morgan; Clementz, Mark T; Kohno, Naoki

    2015-01-01

    Cope's rule describes the evolutionary trend for animal lineages to increase in body size over time. In this study, we tested the validity of Cope's rule for a marine mammal clade, the Pinnipedimorpha, which includes the extinct Desmatophocidae, and extant Phocidae (earless seals), Otariidae (fur seals and sea lions), and Odobenidae (walruses). We tested for the presence of Cope's rule by compiling a large dataset of body size data for extant and fossil pinnipeds and then examined how body size evolved through time. We found that there was a positive relationship between geologic age and body size. However, this trend is the result of differences between early assemblages of small-bodied pinnipeds (Oligocene to early Miocene) and later assemblages (middle Miocene to Pliocene) for which species exhibited greater size diversity. No significant differences were found between the number of increases or decreases in body size within Pinnipedimorpha or within specific pinniped clades. This suggests that the pinniped body size increase was driven by passive diversification into vacant niche space, with the common ancestor of Pinnipedimorpha occurring near the minimum adult body size possible for a marine mammal. Based upon the above results, the evolutionary history of pinnipeds does not follow Cope's rule.

  17. 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.

  18. Geographical variation in body size and sexual size dimorphism in an Australian lizard, Boulenger's Skink (Morethia boulengeri).

    PubMed

    Michael, Damian R; Banks, Sam C; Piggott, Maxine P; Cunningham, Ross B; Crane, Mason; MacGregor, Christopher; McBurney, Lachlan; Lindenmayer, David B

    2014-01-01

    Ecogeographical rules help explain spatial and temporal patterns in intraspecific body size. However, many of these rules, when applied to ectothermic organisms such as reptiles, are controversial and require further investigation. To explore factors that influence body size in reptiles, we performed a heuristic study to examine body size variation in an Australian lizard, Boulenger's Skink Morethia boulengeri from agricultural landscapes in southern New South Wales, south-eastern Australia. We collected tissue and morphological data on 337 adult lizards across a broad elevation and climate gradient. We used a model-selection procedure to determine if environmental or ecological variables best explained body size variation. We explored the relationship between morphology and phylogenetic structure before modeling candidate variables from four broad domains: (1) geography (latitude, longitude and elevation), (2) climate (temperature and rainfall), (3) habitat (vegetation type, number of logs and ground cover attributes), and (4) management (land use and grazing history). Broad phylogenetic structure was evident, but on a scale larger than our study area. Lizards were sexually dimorphic, whereby females had longer snout-vent length than males, providing support for the fecundity selection hypothesis. Body size variation in M. boulengeri was correlated with temperature and rainfall, a pattern consistent with larger individuals occupying cooler and more productive parts of the landscape. Climate change forecasts, which predict warmer temperature and increased aridity, may result in reduced lizard biomass and decoupling of trophic interactions with potential implications for community organization and ecosystem function.

  19. The influence of body size on adult skeletal age estimation methods.

    PubMed

    Merritt, Catherine E

    2015-01-01

    Accurate age estimations are essential to archaeological and forensic analyses. However, reliability for adult skeletal age estimations is poor, especially for individuals over the age of 40 years. This is the first study to show that body size influences skeletal age estimation. The İşcan et al., Lovejoy et al., Buckberry and Chamberlain, and Suchey-Brooks age methods were tested on 764 adult skeletons from the Hamann-Todd and William Bass Collections. Statures ranged from 1.30 to 1.93 m and body masses ranged from 24.0 to 99.8 kg. Transition analysis was used to evaluate the differences in the age estimations. For all four methods, the smallest individuals have the lowest ages at transition and the largest individuals have the highest ages at transition. Short and light individuals are consistently underaged, while tall and heavy individuals are consistently overaged. When femoral length and femoral head diameter are compared with the log-age model, results show the same trend as the known stature and body mass measurements. The skeletal remains of underweight individuals have fewer age markers while those of obese individuals have increased surface degeneration and osteophytic lipping. Tissue type and mechanical loading have been shown to affect bone turnover rates, and may explain the differing patterns of skeletal aging. From an archaeological perspective, the underaging of light, short individuals suggests the need to revisit the current research consensus on the young mortality rates of past populations. From a forensic perspective, understanding the influence of body size will impact efforts to identify victims of mass disasters, genocides, and homicides.

  20. Birth weight, Early Life Course BMI, and Body Size Change: Chains of Risk to Adult Inflammation?

    PubMed Central

    Goosby, Bridget J.; Cheadle, Jacob E.; McDade, Thomas

    2015-01-01

    This paper examines how body size changes over the early life course predict high-sensitivity C-reactive protein in a U.S. based sample. Using three waves of the National Longitudinal Study of Adolescent Health (Add Health), we test the chronic disease epidemiological models of fetal origins, sensitive periods, and chains of risk from birth into adulthood. Few studies link birth weight and changes in obesity status over adolescence and early adulthood to adult obesity and inflammation. Consistent with fetal origins and sensitive periods hypotheses, body size and obesity status at each developmental period, along with increasing body size between periods, are highly correlated with adult CRP. However, the predictive power of earlier life course periods is mediated by body size and body size change at later periods in a pattern consistent with the chains of risk model. Adult increases in obesity had effect sizes of nearly .3sd, and effect sizes from overweight to the largest obesity categories were between .3–1sd. There was also evidence that risk can be offset by weight loss, which suggests that interventions can reduce inflammation and cardiovascular risk, that females are more sensitive to body size changes, and that body size trajectories over the early life course account for African American-and Hispanic-white disparities in adult inflammation. PMID:26685708

  1. Relationships of maternal body size and morphology with egg and clutch size in the diamondback terrapin, Malaclemys terrapin (Testudines: Emydidae)

    USGS Publications Warehouse

    Kern, Maximilian M.; Guzy, Jacquelyn C.; Lovich, Jeffrey E.; Gibbons, J. Whitfield; Dorcas, Michael E.

    2016-01-01

    Because resources are finite, female animals face trade-offs between the size and number of offspring they are able to produce during a single reproductive event. Optimal egg size (OES) theory predicts that any increase in resources allocated to reproduction should increase clutch size with minimal effects on egg size. Variations of OES predict that egg size should be optimized, although not necessarily constant across a population, because optimality is contingent on maternal phenotypes, such as body size and morphology, and recent environmental conditions. We examined the relationships among body size variables (pelvic aperture width, caudal gap height, and plastron length), clutch size, and egg width of diamondback terrapins from separate but proximate populations at Kiawah Island and Edisto Island, South Carolina. We found that terrapins do not meet some of the predictions of OES theory. Both populations exhibited greater variation in egg size among clutches than within, suggesting an absence of optimization except as it may relate to phenotype/habitat matching. We found that egg size appeared to be constrained by more than just pelvic aperture width in Kiawah terrapins but not in the Edisto population. Terrapins at Edisto appeared to exhibit osteokinesis in the caudal region of their shells, which may aid in the oviposition of large eggs.

  2. Effects of meal size, meal type, body temperature, and body size on the specific dynamic action of the marine toad, Bufo marinus.

    PubMed

    Secor, Stephen M; Faulkner, Angela C

    2002-01-01

    Specific dynamic action (SDA), the accumulated energy expended on all physiological processes associated with meal digestion, is strongly influenced by features of both the meal and the organism. We assessed the effects of meal size, meal type, body temperature, and body size on the postprandial metabolic response and calculated SDA of the marine toad, Bufo marinus. Peak postprandial rates of O(2) consumption (.V(O2)) and CO(2) production (.V(CO2)) and SDA increased with meal size (5%-20% of body mass). Postprandial metabolism was impacted by meal type; the digestion of hard-bodied superworms (Zophobas larva) and crickets was more costly than the digestion of soft-bodied earthworms and juvenile rats. An increase in body temperature (from 20 degrees to 35 degrees C) altered the postprandial metabolic profile, decreasing its duration and increasing its magnitude, but did not effect SDA, with the cost of meal digestion remaining constant across body temperatures. Allometric mass exponents were 0.69 for standard metabolic rate, 0.85 for peak postprandial .V(O2), and 1.02 for SDA; therefore, the factorial scope of peak postprandial .V(O2) increased with body mass. The mass of nutritive organs (stomach, liver, intestines, and kidneys) accounted for 38% and 20% of the variation in peak postprandial .V(O2) and SDA, respectively. Toads forced to exercise experienced 25-fold increases in .V(O2) much greater than the 5.5-fold increase experience during digestion. Controlling for meal size, meal type, and body temperature, the specific dynamic responses of B. marinus are similar to those of the congeneric Bufo alvarius, Bufo boreas, Bufo terrestris, and Bufo woodhouseii.

  3. Body size evolution in the Phylum Brachiopoda throughout the Phanerozoic Eon

    NASA Astrophysics Data System (ADS)

    O'Keefe, N.; Zhang, Z.; Augustin, M.; Payne, J.; Paleobiology

    2011-12-01

    Body size is a useful trait for studying the evolution of life on Earth. It is functionally important and therefore reflects how species respond to fluctuating environmental conditions such as changing oxygen and resource availabilities. In this study, we measured 4,993 species of brachiopods, spanning the whole Phanerozoic Eon, from the Treatise of Invertebrate Paleontology. Brachiopods were chosen for the study because they have an extensive and well-studied fossil record, are extremely abundant in rocks of many ages, and are well preserved due to their mineralized shells. Brachiopod mean body size increased significantly during the Devonian period and continued growing throughout the Carboniferous period, but declined sharply after the Permian-Triassic extinction. Soon after, their body size remained stable throughout the Jurassic and again declined during the Cretaceous, never to regain their high body size again. Brachiopod body size displayed different trends throughout the Phanerozoic Eon, which led to a diversification of species.

  4. Characteristics of women with body size satisfaction at midlife: results of the Gender and Body Image (GABI) Study.

    PubMed

    Runfola, Cristin D; Von Holle, Ann; Peat, Christine M; Gagne, Danielle A; Brownley, Kimberly A; Hofmeier, Sara M; Bulik, Cynthia M

    2013-01-01

    This study characterizes the profile of women (N = 1,789) ages 50 and over who report body size satisfaction on a figure rating scale. Satisfied women (12.2%) had a lower body mass index and reported fewer eating disorder symptoms, dieting behaviors, and weight and appearance dissatisfaction. Interestingly, satisfied women exercised more than dissatisfied women, and weight and shape still played a primary role in their self-evaluation. Weight monitoring and appearance-altering behaviors did not differ between groups. Body satisfaction was associated with better overall functioning. This end point appears to represent effortful body satisfaction rather than passive contentment.

  5. Am I Fat? Helping Young Children Accept Differences in Body Size.

    ERIC Educational Resources Information Center

    Ikeda, Joanne; Naworski, Priscilla

    This book offers information and ideas to support teachers, parents and other caregivers in their efforts to help children accept and like their bodies. It includes specific tips on dealing with body image issues and suggestions for role modeling healthy attitudes about body size. It also offers suggestions for healthy eating, increasing physical…

  6. The evolution of body size, antennal size and host use in parasitoid wasps (Hymenoptera: Chalcidoidea): a phylogenetic comparative analysis.

    PubMed

    Symonds, Matthew R E; Elgar, Mark A

    2013-01-01

    Chalcidoid wasps represent one of the most speciose superfamilies of animals known, with ca. 23,000 species described of which many are parasitoids. They are extremely diverse in body size, morphology and, among the parasitoids, insect hosts. Parasitic chalcidoids utilise a range of behavioural adaptations to facilitate exploitation of their diverse insect hosts, but how host use might influence the evolution of body size and morphology is not known in this group. We used a phylogenetic comparative analysis of 126 chalcidoid species to examine whether body size and antennal size showed evolutionary correlations with aspects of host use, including host breadth (specificity), host identity (orders of insects parasitized) and number of plant associates. Both morphological features and identity of exploited host orders show strong phylogenetic signal, but host breadth does not. Larger body size in these wasps was weakly associated with few plant genera, and with more specialised host use, and chalcidoid wasps that parasitize coleopteran hosts tend to be larger. Intriguingly, chalcidoid wasps that parasitize hemipteran hosts are both smaller in size in the case of those parasitizing the suborder Sternorrhyncha and have relatively larger antennae, particularly in those that parasitize other hemipteran suborders. These results suggest there are adaptations in chalcidoid wasps that are specifically associated with host detection and exploitation.

  7. The Evolution of Body Size, Antennal Size and Host Use in Parasitoid Wasps (Hymenoptera: Chalcidoidea): A Phylogenetic Comparative Analysis

    PubMed Central

    Symonds, Matthew R. E.; Elgar, Mark A.

    2013-01-01

    Chalcidoid wasps represent one of the most speciose superfamilies of animals known, with ca. 23,000 species described of which many are parasitoids. They are extremely diverse in body size, morphology and, among the parasitoids, insect hosts. Parasitic chalcidoids utilise a range of behavioural adaptations to facilitate exploitation of their diverse insect hosts, but how host use might influence the evolution of body size and morphology is not known in this group. We used a phylogenetic comparative analysis of 126 chalcidoid species to examine whether body size and antennal size showed evolutionary correlations with aspects of host use, including host breadth (specificity), host identity (orders of insects parasitized) and number of plant associates. Both morphological features and identity of exploited host orders show strong phylogenetic signal, but host breadth does not. Larger body size in these wasps was weakly associated with few plant genera, and with more specialised host use, and chalcidoid wasps that parasitize coleopteran hosts tend to be larger. Intriguingly, chalcidoid wasps that parasitize hemipteran hosts are both smaller in size in the case of those parasitizing the suborder Sternorrhyncha and have relatively larger antennae, particularly in those that parasitize other hemipteran suborders. These results suggest there are adaptations in chalcidoid wasps that are specifically associated with host detection and exploitation. PMID:24205189

  8. 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

  9. The effect of seasonality and body size on the sensitivity of marine amphipods to toxicants.

    PubMed

    Pérez-Landa, Víctor; Belzunce, María Jesús; Franco, Javier

    2008-12-01

    Two factors, seasonality and body size, were studied to determine their influence on the sensitivity of the amphipods Corophium urdaibaiense and Corophium multisetosum to toxicants. Seasonality was studied by comparing LC50 values for cadmium and ammonia toxicity to both species over a year. Body size effect was studied by comparing LC50 values of ammonia in three size categories of C. urdaibaiense. Except for the case of C. urdaibaiense with ammonia as a toxicant, the sensitivity was maximum during summer and minimum during winter. Furthermore, differences in sensitivities were found among the three body size groups studied.

  10. 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

  11. The role of local versus biogeographical processes in influencing diversity and body-size variation in mammal assemblages.

    PubMed

    Lopez, Luiz Carlos S; Figueiredo, Marcos S L; Fracasso, Maria Paula de Aguiar; Mesquita, Daniel Oliveira; Anjos, Ulisses Umbelino; Grelle, Carlos Eduardo Viveiros

    2016-03-01

    Our objective was to estimate and analyze the body-size distribution parameters of terrestrial mammal assemblages at different spatial scales, and to determine whether these parameters are controlled by local ecological processes or by larger-scale ones. Based on 93 local assemblages, plus the complete mammal assemblage from three continents (Africa, North, and South America), we estimated three key distribution parameters (diversity/size slope, skewness, and modal size) and compared the values to those expected if size distributions are mainly controlled by local interactions. Mammal diversity decreased much faster as body size increased than predicted by fractal niche theory, both at continental and at local scales, with continental distributions showing steeper slopes than the localities within them. South America showed a steeper slope (after controlling for species diversity), compared to Africa and North America, at local and continental scales. We also found that skewness and modal body size can show strikingly different correlations with predictor variables, such as species richness and median size, depending on the use of untransformed versus log-transformed data, due to changes in the distribution density generated by log-transformation. The main differences in slope, skewness, and modal size between local and continental scales appear to arise from the same biogeographical process, where small-sized species increase in diversity much faster (due to higher spatial turnover rates) than large-sized species. This process, which can operate even in the absence of competitive saturation at local scales, generates continental assemblages with steeper slopes, smaller modal sizes, and higher right skewness (toward small-sized species) compared to local communities. In addition, historical factors can also affect the size distribution slopes, which are significantly steeper, in South American mammal assemblages (probably due to stronger megafauna extinction events

  12. 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

  13. 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.

  14. Perceptions of Body Size in Mothers and Their Young Children in the Galapagos Islands.

    PubMed

    Waldrop, Julee B; Page, Rachel A; Bentley, Margaret E

    2016-10-01

    Introduction Little specific information has been published about the health of people who live in the Galapagos Islands. As part of determining the status of the nutrition transition that may be occurring in the islands mothers of young children in the Galapagos perceptions of their child's body size and therefore health status was evaluated along with actual body size. Methods This paper presents data collected as part of a pilot study that used a mixed methods approach to identify and describe health and nutrition issues for mother-child pairs on Isla Isabela in Galapagos, Ecuador. It includes participant anthropometric assessment and self-perception of body size using silhouettes for themselves and one of their children along with open-ended questions to elicit further understanding of body size perceptions. Twenty mothers of children greater than 6 months of age but less than 6 years of age were interviewed. Results The women preferred a smaller body size for themselves but a larger body size for their children. Findings of different body size combinations between mothers and children in the same household demonstrated that the island is undergoing or may be post the nutrition transition. Discussion This dual burden of body weights (especially overweight or obese mothers) in the same household with underweight, normal and overweight or obese children and the potential nutrition related chronic disease burden in the future will require more educational resources and innovative health services than are currently available for the people of the Galapagos.

  15. 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

  16. 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

  17. Body size reductions in nonmammalian eutheriodont therapsids (Synapsida) during the end-Permian mass extinction.

    PubMed

    Huttenlocker, Adam K

    2014-01-01

    The extent to which mass extinctions influence body size evolution in major tetrapod clades is inadequately understood. For example, the 'Lilliput effect,' a common feature of mass extinctions, describes a temporary decrease in body sizes of survivor taxa in post-extinction faunas. However, its signature on existing patterns of body size evolution in tetrapods and the persistence of its impacts during post-extinction recoveries are virtually unknown, and rarely compared in both geologic and phylogenetic contexts. Here, I evaluate temporal and phylogenetic distributions of body size in Permo-Triassic therocephalian and cynodont therapsids (eutheriodonts) using a museum collections-based approach and time series model fitting on a regional stratigraphic sequence from the Karoo Basin, South Africa. I further employed rank order correlation tests on global age and clade rank data from an expanded phylogenetic dataset, and performed evolutionary model testing using Brownian (passive diffusion) models. Results support significant size reductions in the immediate aftermath of the end-Permian mass extinction (ca. 252.3 Ma) consistent with some definitions of Lilliput effects. However, this temporal succession reflects a pattern that was underscored largely by Brownian processes and constructive selectivity. Results also support two recent contentions about body size evolution and mass extinctions: 1) active, directional evolution in size traits is rare over macroevolutionary time scales and 2) geologically brief size reductions may be accomplished by the ecological removal of large-bodied species without rapid originations of new small-bodied clades or shifts from long-term evolutionary patterns.

  18. Size-assortative mating and effect of maternal body size on the reproductive output of the nassariid Buccinanops globulosus

    NASA Astrophysics Data System (ADS)

    Avaca, María Soledad; Narvarte, Maite; Martín, Pablo

    2012-04-01

    Size- assortative mating is usually present in populations where there is a positive relationship between female size and reproductive output. In this study, we tested for the presence of sexual size dimorphism, size-assortative mating and the effects of female size on reproductive output in a wild population of Buccinanops globulosus, an endemic nassariid of the Southwestern Atlantic Ocean with direct development. The results showed that: 1) females were larger than males, indicating sexual size dimorphism; 2) mate sizes were significantly correlated, indicating a component of size-assortative mating; 3) males of medium and large size classes were paired with larger females than small-sized males; 4) larger females were paired with large males; 5) maternal body size was positively related to some proxies of reproductive success (number of nurse eggs per egg capsule, egg capsular area and total length at hatching). Our results suggest that larger females may be favored as mates over smaller ones owing to their higher investment per offspring and consequently a larger initial juvenile size as juvenile.

  19. ZResponse to selection, heritability and genetic correlations between body weight and body size in Pacific white shrimp, Litopenaeus vannamei

    NASA Astrophysics Data System (ADS)

    Andriantahina, Farafidy; Liu, Xiaolin; Huang, Hao; Xiang, Jianhai

    2012-03-01

    To quantify the response to selection, heritability and genetic correlations between weight and size of Litopenaeus vannamei, the body weight (BW), total length (TL), body length (BL), first abdominal segment depth (FASD), third abdominal segment depth (TASD), first abdominal segment width (FASW), and partial carapace length (PCL) of 5-month-old parents and of offspnng were measured by calculating seven body measunngs of offspnng produced by a nested mating design. Seventeen half-sib families and 42 full-sib families of L. vannamei were produced using artificial fertilization from 2-4 dams by each sire, and measured at around five months post-metamorphosis. The results show that hentabilities among vanous traits were high: 0.515±0.030 for body weight and 0.394±0.030 for total length. After one generation of selection. the selection response was 10.70% for offspring growth. In the 5th month, the realized heritability for weight was 0.296 for the offspnng generation. Genetic correlations between body weight and body size were highly variable. The results indicate that external morphological parameters can be applied dunng breeder selection for enhancing the growth without sacrificing animals for determining the body size and breed ability; and selective breeding can be improved significantly, simultaneously with increased production.

  20. A mathematical model to predict the size of the pellets formed in freeze pelletization techniques: parameters affecting pellet size.

    PubMed

    Cheboyina, Sreekhar; O'Haver, John; Wyandt, Christy M

    2006-01-01

    A mathematical model was developed based on the theory of drop formation to predict the size of the pellets formed in the freeze pelletization process. Further the model was validated by studying the effect of various parameters on the pellet size such as viscosity of the pellet forming and column liquids, surface/interfacial tension, density difference between pellet forming and column liquids; size, shape, and material of construction of the needle tips and temperatures maintained in the columns. In this study, pellets were prepared from different matrices including polyethylene glycols and waxes. The column liquids studied were silicone oils and aqueous glycerol solutions. The surface/interfacial tension, density difference between pellet forming and column liquids and needle tip size were found to be the most important factors affecting pellet size. The viscosity of the column liquid was not found to significantly affect the size of the pellets. The size of the pellets was also not affected by the pellet forming liquids of low viscosities. An increase in the initial column temperature slightly decreased the pellet size. The mathematical model developed was found to successfully predict the size of the pellets with an average error of 3.32% for different matrices that were studied.

  1. Body Size, Rather Than Male Eye Allometry, Explains Chrysomya megacephala (Diptera: Calliphoridae) Activity in Low Light

    PubMed Central

    Smith, J. L.; Palermo, N. A.; Theobald, J. C.; Wells, J. D.

    2015-01-01

    Male Chrysomya megacephala (F.) blow fly compound eyes contain an unusual area of enlarged dorsal facets believed to allow for increased light capture. This region is absent in females and has been hypothesized to aid in mate tracking in low light conditions or at greater distances. Many traits used in the attraction and capture of mates are allometric, growing at different rates relative to body size. Previous reports concerning C. megacephala eye properties did not include measurements of body size, making the relationship between the specialized eye region and body size unclear. We examined different morphological features of the eye among individuals of varying sizes. We found total eye size scaled proportionately to body size, but the number of enlarged dorsal facets increased as body size increased. This demonstrated that larger males have an eye that is morphologically different than smaller males. On the basis of external morphology, we hypothesized that since larger males have larger and a greater number of dorsally enlarged facets, and these facets are believed to allow for increased light capture, larger males would be active in lower light levels than smaller males and females of equal size. In a laboratory setting, larger males were observed to become active earlier in the morning than smaller males, although they did not remain active later in the evening. However, females followed the same pattern at similar light levels suggesting that overall body size rather than specialized male eye morphology is responsible for increased activity under low light conditions. PMID:26411786

  2. 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.

  3. 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.

  4. Size of the Group IVA Iron Meteorite Parent Body

    NASA Astrophysics Data System (ADS)

    Moskovitz, N.; Walker, R.

    2011-10-01

    The group IVA fractionally crystallized iron meteorites display a diverse range of metallographic cooling rates, ranging from 100 - 6600 K/Myr [1]. These have been attributed to their formation in a metallic core, ˜150 km in radius that cooled to crystallization without any appreciable insulating mantle. Such an exposed core may have resulted from a hit-and-run collision [2] between two large (˜ 103 km) protoplanetary bodies. Here we build upon this formation scenario by incorporating several new constraints. These include (i) a recent U-Pb radiometric closure age of 4565.3 Mya (<2.5 Myr after CAIs) for the group IVA iron Muonionalusta [3], (ii) new measurements and modeling of highly siderophile element compositions for a suite of IVAs, and (iii) consideration of the thermal effects of heating by the decay of the short-lived radionuclide 60Fe.

  5. 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

  6. Body Size Adaptations to Altitudinal Climatic Variation in Neotropical Grasshoppers of the Genus Sphenarium (Orthoptera: Pyrgomorphidae).

    PubMed

    Sanabria-Urbán, Salomón; Song, Hojun; Oyama, Ken; González-Rodríguez, Antonio; Serrano-Meneses, Martin A; Cueva Del Castillo, Raúl

    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.

  7. Luminance controlled pupil size affects Landolt C task performance

    SciTech Connect

    Berman, S.M. ); Fein, G. ); Jewett, D.L.; Ashford, F. )

    1993-02-01

    Subjects judged the orientation of a 2 min. gap Landolt C located at a distance of 2.4 m. The stimuli were presented in central vision on a CRT, at low to medium contrast. The effects of varying the spectrum and luminance of surround lighting were assessed on both pupil size (measured using infrared pupillometry during task performance) and task accuracy. The task display was protected from the surround lighting, so that its luminance and contrast could be varied independently of the changes in the surround lighting. Indirect surround illumination was provided by either two illuminants of very different scotopic spectral content but with the same photopic luminance (Experiments 1 and 3), or by using the same illuminant at two different luminance levels (Experiment 2). In Experiment 3, the effect of changing surround spectrum was compared to the effect of varying task background luminance between 12 cd/m[sup 2] and 73 cd/m[sup 2]. In all experiments, scotopically enhanced surround lighting produced pupil areas which were reduced by almost 50% in comparison with surround lighting with relatively less scotopic luminance. Concomitantly there was improvement in Landolt C task performance with the scotopically enhanced surround lighting at all contrast and luminance levels. In these experiments, smaller pupil sizes were associated with significantly better visual-task performance in spite of lower task retinal illuminance when compared to the condition with larger pupils. These results suggest that changes in surround spectrum can compensate for the effect on task performance of a reduction in task luminance and supports the hypothesis that lighting energy savings could accrue in the workplace by shifting lamp spectra to obtain greater scotopic efficacy.

  8. Luminance controlled pupil size affects Landolt C task performance. Revision

    SciTech Connect

    Berman, S.M.; Fein, G.; Jewett, D.L.; Ashford, F.

    1993-02-01

    Subjects judged the orientation of a 2 min. gap Landolt C located at a distance of 2.4 m. The stimuli were presented in central vision on a CRT, at low to medium contrast. The effects of varying the spectrum and luminance of surround lighting were assessed on both pupil size (measured using infrared pupillometry during task performance) and task accuracy. The task display was protected from the surround lighting, so that its luminance and contrast could be varied independently of the changes in the surround lighting. Indirect surround illumination was provided by either two illuminants of very different scotopic spectral content but with the same photopic luminance (Experiments 1 and 3), or by using the same illuminant at two different luminance levels (Experiment 2). In Experiment 3, the effect of changing surround spectrum was compared to the effect of varying task background luminance between 12 cd/m{sup 2} and 73 cd/m{sup 2}. In all experiments, scotopically enhanced surround lighting produced pupil areas which were reduced by almost 50% in comparison with surround lighting with relatively less scotopic luminance. Concomitantly there was improvement in Landolt C task performance with the scotopically enhanced surround lighting at all contrast and luminance levels. In these experiments, smaller pupil sizes were associated with significantly better visual-task performance in spite of lower task retinal illuminance when compared to the condition with larger pupils. These results suggest that changes in surround spectrum can compensate for the effect on task performance of a reduction in task luminance and supports the hypothesis that lighting energy savings could accrue in the workplace by shifting lamp spectra to obtain greater scotopic efficacy.

  9. Food Serving Size Knowledge in African American Women and the Relationship with Body Mass Index

    ERIC Educational Resources Information Center

    Shah, Meena; Adams-Huet, Beverley; Elston, Elizabeth; Hubbard, Stacy; Carson, Kristin

    2010-01-01

    Objective: To examine serving size knowledge in African Americans and how it is related to body mass index (BMI). Design: Serving size knowledge of food commonly consumed by African Americans was assessed by asking the subjects to select the amount of food considered to be a single serving size by the United States Department of Agriculture and…

  10. Sexually dimorphic body size and development time plasticity in Aedes mosquitoes (Diptera: Culicidae)

    PubMed Central

    Wormington, Jillian D.; Juliano, Steven A.

    2015-01-01

    Background Sexual size dimorphism (SSD) in insects often accompanies a sexual difference in development time, sexual bimaturism (SBM). Goal To determine whether three Aedes mosquito species have similar plasticity in SSD, attain sexual dimorphism through similar strategies, and whether SSD and SBM are associated. Organisms Aedes albopictus, Aedes aegypti, and Aedes triseriatus (Diptera: Culicidae). Methods In four different food availability environments, we quantified plastic responses of relative growth rate (RGR), development time, and adult body size in individually reared males and females. Results Food availability affected RGR differently for the sexes for all three species. The RGR of males and females differed significantly in the 0.1 g/L food treatment. This difference did not account for observed SSD. Food levels over which the largest changes in RGR were observed differed among the species. Male and female adult mass and development time were jointly affected by food availability in a pattern that differed among the three species, so that degree of SSD and SBM changed differentially with food availability for all three species. Development time was generally less sexually dimorphic than mass, particularly in A. albopictus. At lower food levels, A. aegypti and A. triseriatus had accentuated dimorphism in development time. These results, combined with our knowledge of mosquito life history, suggest that a direct benefit of SBM is improbable for mosquitoes and that the observed intersexual differences in development time are more likely byproducts of selection for SSD. PMID:25663826

  11. Body Size Extinction and Origination Selectivity: A Case Study of Marine Gastropods

    NASA Astrophysics Data System (ADS)

    Kuo, E.; Seixas, G.; Faerber, M.; Payne, J.

    2012-12-01

    Body size has received exceptional interest in evolutionary biology because of its correlation with many ecological and physiological traits. Because large size is typically associated with long generation time and small population size, it has been widely assumed that extinction risk is positively correlated with body size. Data from Pleistocene and Holocene terrestrial mammals and birds support this inference. However, there have been few studies on size bias of marine invertebrate animals, so the true extent of this pattern remains unknown. For this study, we compiled genus-level body size data for marine gastropods spanning the entire Phanerozoic. We use this dataset to examine the statistical evidence for size bias in both origination and extinction of marine gastropods. We perform logistic regression analyses on the data from each Phanerozoic stage to determine the association of body size with origination and extinction. Contrary to previous studies on terrestrial vertebrates, we observe no strong or persistent association between body size and the probability that a genus either originated or went extinct during that stage. Hence, our findings indicate that size bias in extinction risk may reflect particular aspects of mammalian biology or anthropogenic environmental change rather than a general pattern of animal evolution.

  12. Effects of prey quality and predator body size on prey DNA detection success in a centipede predator.

    PubMed

    Eitzinger, B; Unger, E M; Traugott, M; Scheu, S

    2014-08-01

    Predator body size and prey quality are important factors driving prey choice and consumption rates. Both factors might affect prey detection success in PCR-based gut content analysis, potentially resulting in over- or underestimation of feeding rates. Experimental evidence, however, is scarce. We examined how body size and prey quality affect prey DNA detection success in centipede predators. Due to metabolic rates increasing with body size, we hypothesized that prey DNA detection intervals will be shorter in large predators than in smaller ones. Moreover, we hypothesized that prey detection intervals of high-quality prey, defined by low carbon-to-nitrogen ratio will be shorter than in low-quality prey due to faster assimilation. Small, medium and large individuals of centipedes Lithobius spp. (Lithobiidae, Chilopoda) were fed Collembola and allowed to digest prey for up to 168 h post-feeding. To test our second hypothesis, medium-sized lithobiids were fed with either Diptera or Lumbricidae. No significant differences in 50% prey DNA detection success time intervals for a 272-bp prey DNA fragment were found between the predator size groups, indicating that body size does not affect prey DNA detection success. Post-feeding detection intervals were significantly shorter in Lumbricidae and Diptera compared to Collembola prey, apparently supporting the second hypothesis. However, sensitivity of diagnostic PCR differed between prey types, and quantitative PCR revealed that concentration of targeted DNA varied significantly between prey types. This suggests that both DNA concentration and assay sensitivity need to be considered when assessing prey quality effects on prey DNA detection success.

  13. Loving transgressions: Queer of color bodies, affective ties, transformative community.

    PubMed

    Carrillo Rowe, Aimee; Royster, Francesca T

    2016-09-12

    This introductory article considers the importance of queer woman of color theorizations of affect in thinking more fully the recent interdisciplinary turn to affect. The affective turn has vitally invited culture and feminist critics to interrogate emotion beyond the individual to examine the political and cultural production of emotion. Even as women of color are often associated with excessive affect, the theoretical contributions women of color make to the field of affect studies are often overlooked. Our introduction and this special issue more broadly examine how this solipsism shapes projects invested in critical knowledge production, as well as the stakes of centering a queer woman of color genealogy. For instance, we argue for the importance of retaining U.S. third-world feminist concepts-like interpellation, oppositional consciousness, and the generative force of negative affects-even as they fall out of favor within affect studies. Centering theory that emerges from the vexed spaces of queer women of color lived experiences generates a vital interdisciplinary conversation that contributes to the ongoing political task of mobilizing affect for social action as a critical praxis. In the articles that follow we see this critical praxis at work in the form of community organizing, music, poetry, and performance art.

  14. Intermittent fasting during winter and spring affects body composition and reproduction of a migratory duck

    USGS Publications Warehouse

    Barboza, P.S.; Jorde, D.G.

    2002-01-01

    We compared food intake, body mass and body composition of male and female black ducks (Anas rubripes) during winter (January-March). Birds were fed the same complete diet ad libitum on consecutive days each week without fasting (control; nine male; nine female) or with either short fasts (2 day.week-1; nine male; nine female), or long fasts (4 day.week-1; eleven male; twelve female). We continued treatments through spring (March-May) to measure the effect of intermittent fasts on body mass and egg production. Daily food intake of fasted birds was up to four times that of unfasted birds. Weekly food intake of males was similar among treatments (364 g.kg-1.week-1) but fasted females consumed more than unfasted females in January (363 g.kg-1.week-1 vs. 225 g.kg-1.week-1). Although both sexes lost 10-14% body mass, fasted females lost less mass and lipid than unfasted females during winter. Total body nitrogen was conserved over winter in both sexes even though the heart and spleen lost mass while the reproductive tract and liver gained mass. Intermittent fasting increased liver, intestinal tissue and digesta mass of females but not of males. Fasting delayed egg production in spring but did not affect size, fertility or hatching of the clutch. Females on long fasts were still heavier than controls after laying eggs. Thus black ducks combine flexibility of food intake with plasticity of digestive tract, liver and adipose tissue when food supply is interrupted during winter. Females modulate body mass for survival and defer reproduction when food supply is interrupted in spring.

  15. Parry–Romberg syndrome affecting one half of the body

    PubMed Central

    Pathi, Jugajyoti; Mishra, Pallavi; Kumar, Harish; Panda, Abikshyeet

    2016-01-01

    Parry-Romberg syndrome, which is also known as progressive hemifacial atrophy, is a poorly understood rare condition. In this condition, the face shows unilateral, slowly progressive atrophy. Disturbance in fat metabolism, viral infection, trauma, heredity, endocrinal disturbances, and autoimmunity are few possible factors in its pathogenesis. Rarely, only this syndrome progresses and involves one half of the body. Our attempt is to present a case of Parry–Romberg syndrome involving one half of the body, which is a rarity in itself. PMID:27583230

  16. How does poaching affect the size of national parks?

    PubMed

    Dobson, Andy; Lynes, Laura

    2008-04-01

    A variety of human activities have detrimental impacts on populations of species the park is designed to protect. These impacts range from direct hunting for trophy or subsistence needs, through vehicular collisions, to the direct loss of habitat due to forestry and agricultural activity. These impacts reduce the effective size of the parks and require changes in management policy that deal both with the direct cause of the problem and the underlying social conflicts that the presence of parks can place on humans in the surrounding communities. Recent studies from the Serengeti illustrate that increases in anti-poaching patrols increase the risk of poacher detection and lead to dramatic declines in levels of poaching. The economic arguments that support investment in anti-poaching patrols, rather than increased sentences for poachers who are caught, can be generalized to examine the costs and benefits of other changes in natural resource management that arise when attempting to manage the impact of anthropogenic activities in and around national parks.

  17. Factors affecting desired family size among preliterate New Guinea mothers.

    PubMed

    Pust, R E; Newman, J S; Senf, J; Stotik, E

    1985-10-01

    A random sample of 331 Enga mothers in Papua New Guinea perceived that an average of 5.96 live births (S.D. = 1.88) were needed to achieve their mean desired completed family size (DFS) of 4.65 children (S.D. = 1.32). The mean of the personal child mortality rates projected by the individual mothers. 194/1000, is very close to the rate of 198/1000 (224 deaths among 1134 live births) experienced by the women as a group and the 177/1000 documented in a 1972 prospective study in the area. This suggests that as a group preliterate women may possess an accurate estimate of prevailing child mortality rates. Considerable interest in family planning was shown. However for cultural or linguistic reasons, the majority (except in the case of the pill and tubal ligation) expressed no opinions about their readiness to use specific modern methods. The mean parity of 43 women seeking tubal ligation was 5.98 (S.D. = 1.81). An integrated maternal health and family planning program focusing on the health benefits to mother and child of the current 3-4-year birth interval seems indicated.

  18. Reproductive rate and body size predict road impacts on mammal abundance.

    PubMed

    Rytwinski, Trina; Fahrig, Lenore

    2011-03-01

    It has been hypothesized that mobile species should be more negatively affected by road mortality than less-mobile species because they interact with roads more often, and that species with lower reproductive rates and longer generation times should be more susceptible to road effects because they will be less able to rebound quickly from population declines. Taken together, these hypotheses suggest that, in general, larger species should be more affected by road networks than smaller species because larger species generally have lower reproductive rates and longer generation times and are more mobile than smaller species. We tested these hypotheses by estimating relative abundances of 17 mammal species across landscapes ranging in road density within eastern Ontario, Canada. For each of the 13 species for which detectability was not related to road density, we quantified the relationship between road density and relative abundance. We then tested three cross-species predictions: that the slope of the relationship between road density and abundance should become increasingly negative with (1) decreasing annual reproductive rate; (2) increasing home range area (an indicator of movement range); and (3) increasing body size. All three predictions were supported in univariate models, with R2 values of 0.68, 0.50, and 0.52 respectively. The best overall model based on AICc contained both reproductive rate (P = 0.008) and body size (P = 0.072) and explained 77% of the variation in the slope of the relationship between road density and abundance. Our results suggest that priority should be placed on mitigating road effects on large mammals with low reproductive rates.

  19. Body size dissatisfaction among young adults from the 1982 Pelotas birth cohort

    PubMed Central

    Mintem, G C; Horta, B L; Domingues, M R; Gigante, D P

    2015-01-01

    Background/Objectives: To identify the prevalence and factors associated with body dissatisfaction. Subjects/Methods: Birth cohort study investigating 4100 subjects (2187 men and 1913 women) aged between 22 and 23 years who answered questionnaires, including the body satisfaction Stunkard Scale were included in the study; they were weighed and measured. Multinomial logistic regression was used in the crude and adjusted analyses. Results: The prevalence of body dissatisfaction was 64% (95% CI, 62.7–65.6); 42% (95% CI, 40.6–43.6) of the subjects reported feeling larger than the desired body size, and 22% (95% CI, 20.7–23.3) reported feeling smaller than desired. Underweight subjects, subjects with less schooling, poor and sedentary male subjects with low psychological well-being and female subjects who were already mothers were more likely to express body dissatisfaction, perceiving their body as smaller than the desirable body size. The prevalence of body dissatisfaction was also high among overweight subjects, subjects with a high socioeconomic status and married female subjects, who perceived their body size as too large. Minor psychiatric disorders were associated with body dissatisfaction in all subjects, regardless of perceiving themselves as larger or smaller than the desired body size. Most women perceived themselves as larger, but similar proportions of men perceived themselves as too small or too large. Conclusions: Body dissatisfaction was observed among men and women with normal weight, but it was more evident in the obese individuals. Regardless of the nutritional status, both men and women should be appropriately counseled because body size perception can lead to unhealthy behaviors in relation to diet and physical activity. PMID:25074390

  20. Clinal variation in body and cell size in a widely distributed vertebrate ectotherm.

    PubMed

    Litzgus, Jacqueline D; DuRant, Sarah E; Mousseau, Timothy A

    2004-08-01

    Bergmann's rule states that, among conspecific populations, individuals are larger in cooler than in warmer environments as a consequence of selection related to heat conservation. Many of the most comprehensive assessments of Bergmann's rule to date have examined clinal patterns in body size among species assemblages. Our study is a more direct test of Bergmann's rule because we examine the pattern within a single, widely distributed species. We examined geographic variation in body and cell size in the spotted turtle ( Clemmys guttata). Our analysis of 818 turtles collected from the entire range (45-28 degrees N), indicated that body size increased with latitude; however, the relationship was driven by a population of large turtles at the northern extreme of the species' range. When the northern population was removed from the analyses, Bergmann's rule was not supported, and the smallest turtles occurred near the central part of the species' distribution. Recent literature has suggested that latitudinal clines in body size may simply be a physiological byproduct of the effects of temperature on cell division, resulting in larger cells, and hence larger organisms, from cooler temperatures. Measurements of the diameter of skin cells did not support the hypothesis that cell size increases with latitude and decreases with temperature in the spotted turtle, nor was there a significant relationship between body size and cell size. Our study suggests that neither Bergmann's rule nor cell size variation sufficiently explain the body size cline observed in the spotted turtle. We hypothesize that patterns in body size are related to variation in female size at maturity and reproductive cycles.

  1. Sexual selection uncouples the evolution of brain and body size in pinnipeds.

    PubMed

    Fitzpatrick, J L; Almbro, M; Gonzalez-Voyer, A; Hamada, S; Pennington, C; Scanlan, J; Kolm, N

    2012-07-01

    The size of the vertebrate brain is shaped by a variety of selective forces. Although larger brains (correcting for body size) are thought to confer fitness advantages, energetic limitations of this costly organ may lead to trade-offs, for example as recently suggested between sexual traits and neural tissue. Here, we examine the patterns of selection on male and female brain size in pinnipeds, a group where the strength of sexual selection differs markedly among species and between the sexes. Relative brain size was negatively associated with the intensity of sexual selection in males but not females. However, analyses of the rates of body and brain size evolution showed that this apparent trade-off between sexual selection and brain mass is driven by selection for increasing body mass rather than by an actual reduction in male brain size. Our results suggest that sexual selection has important effects on the allometric relationships of neural development.

  2. Body size distributions of the pale grass blue butterfly in Japan: Size rules and the status of the Fukushima population

    NASA Astrophysics Data System (ADS)

    Taira, Wataru; Iwasaki, Mayo; Otaki, Joji M.

    2015-07-01

    The body size of the pale grass blue butterfly, Zizeeria maha, has been used as an environmental indicator of radioactive pollution caused by the Fukushima nuclear accident. However, geographical and temporal size distributions in Japan and temperature effects on size have not been established in this species. Here, we examined the geographical, temporal, and temperature-dependent changes of the forewing size of Z. maha argia in Japan. Butterflies collected in 2012 and 2013 from multiple prefectures throughout Japan demonstrated an inverse relationship of latitude and forewing size, which is the reverse of Bergmann’s cline. The Fukushima population was significantly larger than the Aomori and Miyagi populations and exhibited no difference from most of the other prefectural populations. When monitored at a single geographic locality every other month, forewing sizes were the largest in April and the smallest in August. Rearing larvae at a constant temperature demonstrated that forewing size followed the temperature-size rule. Therefore, the converse Bergmann’s rule and the temperature-size rule coexist in this multivoltine species. Our study establishes this species as a useful environmental indicator and supports the idea that the size reduction observed only in Fukushima Prefecture in 2011 was caused by the environmental stress of radioactive pollution.

  3. Body size distributions of the pale grass blue butterfly in Japan: Size rules and the status of the Fukushima population

    PubMed Central

    Taira, Wataru; Iwasaki, Mayo; Otaki, Joji M.

    2015-01-01

    The body size of the pale grass blue butterfly, Zizeeria maha, has been used as an environmental indicator of radioactive pollution caused by the Fukushima nuclear accident. However, geographical and temporal size distributions in Japan and temperature effects on size have not been established in this species. Here, we examined the geographical, temporal, and temperature-dependent changes of the forewing size of Z. maha argia in Japan. Butterflies collected in 2012 and 2013 from multiple prefectures throughout Japan demonstrated an inverse relationship of latitude and forewing size, which is the reverse of Bergmann’s cline. The Fukushima population was significantly larger than the Aomori and Miyagi populations and exhibited no difference from most of the other prefectural populations. When monitored at a single geographic locality every other month, forewing sizes were the largest in April and the smallest in August. Rearing larvae at a constant temperature demonstrated that forewing size followed the temperature-size rule. Therefore, the converse Bergmann’s rule and the temperature-size rule coexist in this multivoltine species. Our study establishes this species as a useful environmental indicator and supports the idea that the size reduction observed only in Fukushima Prefecture in 2011 was caused by the environmental stress of radioactive pollution. PMID:26197998

  4. Lean birds in the city: body size and condition of house sparrows along the urbanization gradient.

    PubMed

    Liker, A; Papp, Z; Bókony, V; Lendvai, A Z

    2008-07-01

    1. Urbanized habitats differ from natural ones in several ecological features, including climate, food availability, strength of predation and competition. Although the effects of urbanization on avian community composition are well known, there is much less information about how individual birds are affected by these human-generated habitat differences. 2. In this study we investigated the relationships between the morphological characteristics and the degree of habitat urbanization in house sparrows, Passer domesticus (Linne 1758) . We collected data for more than 1000 non-breeding adult birds in Hungary between 1997 and 2006, from seven sites including farmlands, suburban areas and city centres. 3. We found that the body mass, tarsus length and body condition of free-living sparrows differed among the sites: birds in more urbanized habitats were consistently smaller and in worse condition than birds in more rural habitats. A composite measure of habitat urbanization (based on building density, road density and vegetation cover) explained over 75% of variance between sites in the studied traits, after we controlled for the effects of sex, year, season and time of capture. 4. The difference in body mass between rural and urban sparrows was significant when birds were kept in aviaries under identical conditions, with constant ad libitum food availability. It is therefore unlikely that the reduced body size and condition of urban sparrows are a consequence of reduced access to food for adults (e.g. due to strong competition), or their short-term responses to high food predictability (e.g. by strategic mass regulation). 5. We suggest that habitat differences in nestling development or adaptive divergence of sparrow populations due to distinct environmental conditions (such as differing predation pressure) may account for the differences along the urbanization gradient.

  5. 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.

  6. Body size clines in sceloporus lizards: proximate mechanisms and demographic constraints.

    PubMed

    Sears, Michael W; Angilletta, Michael J

    2004-12-01

    Although most species of animals examined to date exhibit Bergmann's clines in body size, squamates tend to exhibit opposing patterns. Squamates might exhibit reversed Bergmann's clines because they tend to behaviorally regulate their body temperature effectively; the outcome of this thermoregulation is that warmer environments enable longer daily and annual durations of activity than cooler environments. Lizards of the genus Sceloporus provide an opportunity to understand the factors that give rise to contrasting thermal clines in body size because S. undulatus exhibits a standard Bergmann's cline whereas S. graciosus exhibits a reverse Bergmann's cline. Interestingly, rapid growth by individuals of both species involves adjustments of physiological processes that enable more efficient use of food. Patterns of adult body size are likely the evolutionary consequence of variation in juvenile survivorship among populations. In S. undulatus, delayed maturation at a relatively large body size is exhibited in cooler environments where juveniles experience higher survivorship, resulting in a Bergmann's cline. In S. graciosus, high juvenile survivorship is not consistently found in cooler environments, resulting in no cline or a reversed Bergmann's cline, i.e., geographic patterns in body size aren't necessarily produced by natural selection. Thus, discerning the mechanistic links between the thermal physiology of an organism and environment-specific rates of mortality will be critical to understanding the evolution of body size in relation to environmental temperature.

  7. Exploring the genetic signature of body size in Yucatan miniature pig.

    PubMed

    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.

  8. 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

  9. Comparing Apples and Pears: Women's Perceptions of Their Body Size and Shape

    PubMed Central

    Hediger, Mary L.; Sundaram, Rajeshwari; Stanford, Joseph B.; Peterson, C. Matthew; Croughan, Mary S.; Chen, Zhen; Louis, Germaine M. Buck

    2012-01-01

    Abstract Background Obesity is a growing public health problem among reproductive-aged women, with consequences for chronic disease risk and reproductive and obstetric morbidities. Evidence also suggests that body shape (i.e., regional fat distribution) may be independently associated with risk, yet it is not known if women adequately perceive their shape. This study aimed to assess the validity of self-reported body size and shape figure drawings when compared to anthropometric measures among reproductive-aged women. Methods Self-reported body size was ascertained using the Stunkard nine-level figures and self-reported body shape using stylized pear, hourglass, rectangle, and apple figures. Anthropometry was performed by trained researchers. Body size and body mass index (BMI) were compared using Spearman's correlation coefficient. Fat distribution indicators were compared across body shapes for nonobese and obese women using analysis of variance (ANOVA) and Fisher's exact test. Percent agreement and kappa statistics were computed for apple and pear body shapes. Results The 131 women studied were primarily Caucasian (81%), aged 32 years, with a mean BMI of 27.1 kg/m2 (range 16.6–52.8 kg/m2). The correlation between body size and BMI was 0.85 (p<0.001). Among nonobese women, waist-to-hip ratios (WHR) were 0.75, 0.75, 0.80, and 0.82 for pear, hourglass, rectangle, and apple, respectively (p<0.001). Comparing apples and pears, the percent agreement (kappa) for WHR≥0.80 was 83% (0.55). Conclusions Self-reported size and shape were consistent with anthropometric measures commonly used to assess obesity and fat distribution, respectively. Self-reported body shape may be a useful proxy measure in addition to body size in large-scale surveys. PMID:22873752

  10. 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

  11. Predictive equations for the estimation of body size in seals and sea lions (Carnivora: Pinnipedia).

    PubMed

    Churchill, Morgan; Clementz, Mark T; Kohno, Naoki

    2014-08-01

    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

  12. Body Size Shifts in Philippine Reef Fishes: Interfamilial Variation in Responses to Protection

    PubMed Central

    Fidler, Robert Y.; Maypa, Aileen; Apistar, Dean; White, Alan; Turingan, Ralph G.

    2014-01-01

    As a consequence of intense fishing pressure, fished populations experience reduced population sizes and shifts in body size toward the predominance of smaller and early maturing individuals. Small, early-maturing fish exhibit significantly reduced reproductive output and, ultimately, reduced fitness. As part of resource management and biodiversity conservation programs worldwide, no-take marine protected areas (MPAs) are expected to ameliorate the adverse effects of fishing pressure. In an attempt to advance our understanding of how coral reef MPAs meet their long-term goals, this study used visual census data from 23 MPAs and fished reefs in the Philippines to address three questions: (1) Do MPAs promote shifts in fish body size frequency distribution towards larger body sizes when compared to fished reefs? (2) Do MPA size and (3) age contribute to the efficacy of MPAs in promoting such shifts? This study revealed that across all MPAs surveyed, the distribution of fishes between MPAs and fished reefs were similar; however, large-bodied fish were more abundant within MPAs, along with small, young-of-the-year individuals. Additionally, there was a significant shift in body size frequency distribution towards larger body sizes in 12 of 23 individual reef sites surveyed. Of 22 fish families, eleven demonstrated significantly different body size frequency distributions between MPAs and fished reefs, indicating that shifts in the size spectrum of fishes in response to protection are family-specific. Family-level shifts demonstrated a significant, positive correlation with MPA age, indicating that MPAs become more effective at increasing the density of large-bodied fish within their boundaries over time. PMID:24833509

  13. Biogeography and divergent patterns of body size disparification in North American minnows.

    PubMed

    Martin, Samuel D; Bonett, Ronald M

    2015-12-01

    Body size is one of the most important traits influencing an organism's ecology and a major axis of evolutionary change. We examined body size disparification in the highly speciose North American minnows (Cyprinidae), which exhibit diverse body sizes and ecologies, including the giant piscivorous pikeminnows. We estimated a novel phylogeny for 285 species based on a supermatrix alignment of seven mitochondrial and ten nuclear genes, and used this to reconstruct ancestral body sizes (log-total length) and ancestral area. Additionally, given that fishes inhabiting Pacific drainages have historically been subjected to frequent local extinctions due to periodic flooding, droughts, and low drainage connectivity, we also compared body size disparification between the highly speciose Atlantic drainages and comparatively depauperate Pacific drainages. We found that dispersal between Atlantic and Pacific drainages has been infrequent and generally occurred in minnows with southerly distributions, where drainage systems are younger and less stable. The long isolation between Atlantic and Pacific drainages has allowed for divergent patterns of morphological disparification; we found higher rates of body size disparification in minnows from the environmentally harsher Pacific drainages. We propose several possible explanations for the observed patterns of size disparification in the context of habitat stability, niche space, and species diversification.

  14. The role of body size in predator recognition by untrained birds.

    PubMed

    Beránková, Jana; Veselý, Petr; Fuchs, Roman

    2015-11-01

    It is supposed that body size serves as an important cue in the recognition of relevant stimuli in nature. As predators of varying body size pose differing levels of threat, their potential prey should be able to discriminate between them. We tested the reaction of great tits (Parus major) to the dummies of their common predator (the European sparrowhawk-Accipiter nisus) in natural and reduced body sizes under laboratory conditions. All of the tested dummies possessed local raptor-specific features (hooked beak, claws with talons, and conspicuous eyes), but differed in global species-specific features: body size (large - the size of a sparrowhawk, small - the size of a great tit) and colouration (sparrowhawk, great tit, robin, and pigeon). The sparrowhawk-coloured dummies evoked fear regardless of their size while both great tit- and pigeon-coloured dummies evoked no fear reaction. The body size was used as the cue only for the discrimination of the robin-coloured dummies. The differences in reactions to the dummies with robin colouration (species unimportant to the great tits) could be explained as that the tits are able to recognize these birds in nature, but not so undoubtedly as the predator or the conspecific.

  15. Body-size distributions and size-spectra: universal indicators of ecological status?

    PubMed Central

    Petchey, Owen L.; Belgrano, Andrea

    2010-01-01

    The sizes of individual organisms, rather than their taxonomy, are used to inform management and conservation in some aquatic ecosystems. The European Science Foundation Research Network, SIZEMIC, facilitates integration of such approaches with the more taxonomic approaches used in terrestrial ecology. During its 4-year tenure, the Network is bringing together researchers from disciplines including theorists, empiricists, government employees, and practitioners, via a series of meetings, working groups and research visits. The research conducted suggests that organismal size, with a generous helping of taxonomy, provides the most probable route to universal indicators of ecological status. PMID:20444761

  16. The Importance of Strength, Speed, and Body Size for Team Success in Women's Intercollegiate Volleyball.

    ERIC Educational Resources Information Center

    Morrow, James R., Jr.; And Others

    1979-01-01

    In evaluating performance of women's volleyball teams it was found that the quality of physical size as represented by body composition and strength was more important than the combination of height and lean weight. (JD)

  17. Nano-sized polystyrene affects feeding, behavior and physiology of brine shrimp Artemia franciscana larvae.

    PubMed

    Bergami, Elisa; Bocci, Elena; Vannuccini, Maria Luisa; Monopoli, Marco; Salvati, Anna; Dawson, Kenneth A; Corsi, Ilaria

    2016-01-01

    Nano-sized polymers as polystyrene (PS) constitute one of the main challenges for marine ecosystems, since they can distribute along the whole water column affecting planktonic species and consequently disrupting the energy flow of marine ecosystems. Nowadays very little knowledge is available on the impact of nano-sized plastics on marine organisms. Therefore, the present study aims to evaluate the effects of 40nm anionic carboxylated (PS-COOH) and 50nm cationic amino (PS-NH2) polystyrene nanoparticles (PS NPs) on brine shrimp Artemia franciscana larvae. No signs of mortality were observed at 48h of exposure for both PS NPs at naplius stage but several sub-lethal effects were evident. PS-COOH (5-100μg/ml) resulted massively sequestered inside the gut lumen of larvae (48h) probably limiting food intake. Some of them were lately excreted as fecal pellets but not a full release was observed. Likewise, PS-NH2 (5-100µg/ml) accumulated in larvae (48h) but also adsorbed at the surface of sensorial antennules and appendages probably hampering larvae motility. In addition, larvae exposed to PS-NH2 undergo multiple molting events during 48h of exposure compared to controls. The activation of a defense mechanism based on a physiological process able to release toxic cationic NPs (PS-NH2) from the body can be hypothesized. The general observed accumulation of PS NPs within the gut during the 48h of exposure indicates a continuous bioavailability of nano-sized PS for planktonic species as well as a potential transfer along the trophic web. Therefore, nano-sized PS might be able to impair food uptake (feeding), behavior (motility) and physiology (multiple molting) of brine shrimp larvae with consequences not only at organism and population level but on the overall ecosystem based on the key role of zooplankton on marine food webs.

  18. Cajal body number and nucleolar size correlate with the cell body mass in human sensory ganglia neurons.

    PubMed

    Berciano, Maria T; Novell, Mariona; Villagra, Nuria T; Casafont, Iñigo; Bengoechea, Rocio; Val-Bernal, J Fernado; Lafarga, Miguel

    2007-06-01

    This paper studies the cell size-dependent organization of the nucleolus and Cajal bodies (CBs) in dissociated human dorsal root ganglia (DRG) neurons from autopsy tissue samples of patients without neurological disease. The quantitative analysis of nucleoli with an anti-fibrillarin antibody showed that all neurons have only one nucleolus. However, the nucleolar volume and the number of fibrillar centers per nucleolus significantly increase as a function of cell body size. Immunostaining for coilin demonstrated the presence of numerous CBs in DRG neurons (up to 20 in large size neurons). The number of CBs per neuron correlated positively with the cell body volume. Light and electron microscopy immunocytochemical analysis revealed the concentration of coilin, snRNPs, SMN and fibrillarin in CBs of DRG neurons. CBs were frequently associated with the nucleolus, active chromatin domains and PML bodies, but not with telomeres. Our results support the view that the nucleolar volume and number of both fibrillar centers and CBs depend on the cell body mass, a parameter closely related to transcriptional and synaptic activity in mammalian neurons. Moreover, the unusual large number of CBs could facilitate the transfer of RNA processing components from CBs to nucleolar and nucleoplasmic sites of RNA processing.

  19. 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.

  20. 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.

  1. Does smoking affect body weight and obesity in China?

    PubMed

    Fang, Hai; Ali, Mir M; Rizzo, John A

    2009-12-01

    An inverse relationship between smoking and body weight has been documented in the medical literature, but the effect of cigarette smoking on obesity remains inconclusive. In addition, the evidence is mixed on whether rising obesity rates are an unintended consequence of successful anti-smoking policies. This study re-examines these relationships using data from China, the largest consumer and manufacturer of tobacco in the world that is also experiencing a steady rise in obesity rates. We focus on the impact of the total number of cigarettes smoked per day on individuals' body mass index (BMI) and on the likelihood of being overweight and obese. Instrumental variables estimation is used to correct for the endogeneity of cigarette smoking. We find a moderate negative and significant relationship between cigarette smoking and BMI. Smoking is also negatively related to being overweight and obese, but the marginal effects are small and statistically insignificant for being obese. Quantile regression analyses reveal that the association between smoking and BMI is quite weak among subjects whose BMIs are at the high end of the distribution but are considerably stronger among subjects in the healthy weight range. Ordered probit regression analyses also confirm these findings. Our results thus reconcile an inverse average effect of smoking on body weight with the absence of any significant effect on obesity. From a policy perspective these findings suggest that, while smoking cessation may lead to moderate weight gain among subjects of healthy weight, the effects on obese subjects are modest and should not be expected to lead to a large increase in obesity prevalence rates.

  2. Predator-prey body size relationships when predators can consume prey larger than themselves.

    PubMed

    Nakazawa, Takefumi; Ohba, Shin-Ya; Ushio, Masayuki

    2013-06-23

    As predator-prey interactions are inherently size-dependent, predator and prey body sizes are key to understanding their feeding relationships. To describe predator-prey size relationships (PPSRs) when predators can consume prey larger than themselves, we conducted field observations targeting three aquatic hemipteran bugs, and assessed their body masses and those of their prey for each hunting event. The data revealed that their PPSR varied with predator size and species identity, although the use of the averaged sizes masked these effects. Specifically, two predators had slightly decreased predator-prey mass ratios (PPMRs) during growth, whereas the other predator specialized on particular sizes of prey, thereby showing a clear positive size-PPMR relationship. We discussed how these patterns could be different from fish predators swallowing smaller prey whole.

  3. Obesity Bias in Children: The Role of Actual and Perceived Body Size

    ERIC Educational Resources Information Center

    Kornilaki, Ekaterina N.

    2015-01-01

    The aim of this study was to examine how children perceive their body size and whether their actual or perceived body size can explain their anti-fat views. Four hundred and fourteen 5-6, 7-8 and 9-10-year-old children were read short vignettes depicting two characters, one possessing a positive and the other a negative quality. Following each…

  4. Physical Activity, Body Size, Intentional Weight Loss and Breast Cancer Risk: Fellowship

    DTIC Science & Technology

    1999-10-01

    exercised frequently. More pronounced were results obtained from the model examining the joint effects of early-life physical activity and net lifetime...Number: DAMD17-97-1-7235 TITLE:. Physical Activity , Body Size, Intentional Weight Loss and Breast Cancer Risk: Fellowship PRINCIPAL INVESTIGATOR: Suzanne...SUBTITLE 5. FUNDING NUMBERS Physical Activity , Body Size, Intentional Weight Loss and Breast Cancer: DAMD 17-97-1-7235 Risk: Fellowship 6. AUTHORIS

  5. Reproductive and resource benefits to large female body size in a mammal with female-biased sexual size dimorphism

    SciTech Connect

    Fokidis, H.B., T.S. Risch and T.C. Glenn

    2007-01-01

    Factors underlying the evolution of female-biased sexual size dimorphism in mammals are poorly understood. In an effort to better understand these factors we tested whether larger female southern flying squirrels, Glaucomys volans, gained reproductive advantages (larger litters or more male mates) and direct resource benefits, such as larger home ranges or access to more food (i.e. mast-producing trees). As dimorphism can vary with age in precocial breeding species, we compared females during their first reproduction and during a subsequent breeding attempt. Females were not significantly larger or heavier than males at first reproduction, but became about 7% heavier and 22% larger than males at subsequent breeding. Larger females produced larger litters and had home ranges containing a greater proportion of upland hardwood trees. Female body size was not associated with either multiple male mating or home range size, but females with larger home ranges had higher indexes of body condition. Females in precocial breeding flying squirrels initiate reproduction before sexual size dimorphism is evident, and thus, may be allocating resources to both reproduction and growth simultaneously, or delaying growth entirely. Larger females produce more pups and have access to more food resources. Thus, selection for increased female size may partly explain how female-biased sexual size dimorphism is maintained in this species.

  6. 78 FR 7659 - Revised Medical Criteria for Evaluating Congenital Disorders That Affect Multiple Body Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-04

    ... impairments that affect multiple body systems in adults and children under titles II and XVI of the Social... eligibility or filing for benefits, call our national toll-free number, 1-800-772-1213, or TTY 1-800-325-0778... the appropriate affected body system(s), such as musculoskeletal, special senses and...

  7. Ostracod Body Size: Locality in Accordance with Cope's and Bergmann's Rules

    NASA Astrophysics Data System (ADS)

    Vo, T.; Tolosa, R.; Heim, N. A.; Payne, J.

    2014-12-01

    A wide range of climates exists on planet Earth, and the different kinds of life inhabiting each area vary greatly in accordance with its topography and weather conditions. The nature of each climate is in part determined by its latitude—latitudes closer to 90º suggest a colder climate while latitudes closer to 0º suggest a warmer, more tropical climate. The evolution of organisms is expected to differ in different parts of the world because environment plays such a significant role in it. In our study, we focus on the relationship between location and the extent to which the evolution of ostracod body size follows Cope's Rule (i.e., the tendency for body size to increase over time) and Bergmann's Rule (i.e., body size decreases with temperature) from the Ordovician to the Holocene. Using body sizes of ostracod occurrences, we explored the relationships among size, latitude and time. Modern ecosystems near the poles are more sensitive to environmental and climate change than those near the equator, we hypothesized that ostracods with latitudes closer to the poles will follow Cope's Rule more closely. To test this hypothesis, we compared body size and latitude as well as trends of body size evolution over time in tropical, temperate and polar regions. The graphs produced showed that over different latitudes, there was a decreasing trend in the mean size of ostracods over time. This means that the evolution of ostracod body size does not follow Cope's Rule any more in polar and temperate regions than it does in tropical regions. In fact, our data suggests that ostracods do not necessarily follow Cope's Rule or Bergmann's Rule at all, which concurs with a notion that has been previously brought up—the possibility that ectothermic marine organisms are exceptions to Bergmann's Rule.

  8. Can foraging ecology drive the evolution of body size in a diving endotherm?

    PubMed

    Cook, Timothée R; Lescroël, Amélie; Cherel, Yves; Kato, Akiko; Bost, Charles-André

    2013-01-01

    Within a single animal species, different morphs can allow for differential exploitation of foraging niches between populations, while sexual size dimorphism can provide each sex with access to different resources. Despite being potentially important agents of evolution, resource polymorphisms, and the way they operate in wild populations, remain poorly understood. In this study, we examine how trophic factors can select for different body sizes between populations and sexes in a diving endotherm. Dive depth and duration are positively related to body size in diving birds and mammals, a relationship explained by a lower mass-specific metabolic rate and greater oxygen stores in larger individuals. Based on this allometry, we predict that selection for exploiting resources situated at different depths can drive the evolution of body size in species of diving endotherms at the population and sexual level. To test this prediction, we studied the foraging ecology of Blue-eyed Shags, a group of cormorants with male-biased sexual size dimorphism from across the Southern Ocean. We found that mean body mass and relative difference in body mass between sexes varied by up to 77% and 107% between neighbouring colonies, respectively. Birds from colonies with larger individuals dived deeper than birds from colonies with smaller individuals, when accounting for sex. In parallel, males dived further offshore and deeper than females and the sexual difference in dive depth reflected the level of sexual size dimorphism at each colony. We argue that body size in this group of birds is under intense selection for diving to depths of profitable benthic prey patches and that, locally, sexual niche divergence selection can exaggerate the sexual size dimorphism of Blue-eyed Shags initially set up by sexual selection. Our findings suggest that trophic resources can select for important geographic micro-variability in body size between populations and sexes.

  9. Can Foraging Ecology Drive the Evolution of Body Size in a Diving Endotherm?

    PubMed Central

    Cook, Timothée R.; Lescroël, Amélie; Cherel, Yves; Kato, Akiko; Bost, Charles-André

    2013-01-01

    Within a single animal species, different morphs can allow for differential exploitation of foraging niches between populations, while sexual size dimorphism can provide each sex with access to different resources. Despite being potentially important agents of evolution, resource polymorphisms, and the way they operate in wild populations, remain poorly understood. In this study, we examine how trophic factors can select for different body sizes between populations and sexes in a diving endotherm. Dive depth and duration are positively related to body size in diving birds and mammals, a relationship explained by a lower mass-specific metabolic rate and greater oxygen stores in larger individuals. Based on this allometry, we predict that selection for exploiting resources situated at different depths can drive the evolution of body size in species of diving endotherms at the population and sexual level. To test this prediction, we studied the foraging ecology of Blue-eyed Shags, a group of cormorants with male-biased sexual size dimorphism from across the Southern Ocean. We found that mean body mass and relative difference in body mass between sexes varied by up to 77% and 107% between neighbouring colonies, respectively. Birds from colonies with larger individuals dived deeper than birds from colonies with smaller individuals, when accounting for sex. In parallel, males dived further offshore and deeper than females and the sexual difference in dive depth reflected the level of sexual size dimorphism at each colony. We argue that body size in this group of birds is under intense selection for diving to depths of profitable benthic prey patches and that, locally, sexual niche divergence selection can exaggerate the sexual size dimorphism of Blue-eyed Shags initially set up by sexual selection. Our findings suggest that trophic resources can select for important geographic micro-variability in body size between populations and sexes. PMID:23409169

  10. Consistent size-independent harvest selection on fish body shape in two recreationally exploited marine species.

    PubMed

    Alós, Josep; Palmer, Miquel; Linde-Medina, Marta; Arlinghaus, Robert

    2014-06-01

    Harvesting wild animals may exert size-independent selection pressures on a range of morphological, life history, and behavioral traits. Most work so far has focused on selection pressures on life history traits and body size as morphological trait. We studied here how recreational fishing selects for morphological traits related to body shape, which may correlate with underlying swimming behavior. Using landmark-based geometric morphometrics, we found consistent recreational fishing-induced selection pressures on body shape in two recreationally exploited marine fish species. We show that individuals with larger-sized mouths and more streamlined and elongated bodies were more vulnerable to passively operated hook-and-line fishing independent of the individual's body size or condition. While the greater vulnerability of individuals with larger mouth gapes can be explained by the direct physical interaction with hooks, selection against streamlined and elongated individuals could either involve a specific foraging mode or relate to underlying elevated swimming behavior. Harvesting using passive gear is common around the globe, and thus, size-independent selection on body shape is expected to be widespread potentially leaving behind individuals with smaller oral gapes and more compact bodies. This might have repercussions for food webs by altering foraging and predation.

  11. Genes predict long distance migration and large body size in a migratory fish, Pacific lamprey

    PubMed Central

    Hess, Jon E; Caudill, Christopher C; Keefer, Matthew L; McIlraith, Brian J; Moser, Mary L; Narum, Shawn R

    2014-01-01

    Elucidation of genetic mechanisms underpinning migratory behavior could help predict how changes in genetic diversity may affect future spatiotemporal distribution of a migratory species. This ability would benefit conservation of one such declining species, anadromous Pacific lamprey (Entosphenus tridentatus). Nonphilopatric migration of adult Pacific lamprey has homogenized population-level neutral variation but has maintained adaptive variation that differentiates groups based on geography, run-timing and adult body form. To investigate causes for this adaptive divergence, we examined 647 adult lamprey sampled at a fixed location on the Columbia River and radiotracked during their subsequent upstream migration. We tested whether genetic variation [94 neutral and adaptive single nucleotide polymorphisms (SNPs) previously identified from a genomewide association study] was associated with phenotypes of migration distance, migration timing, or morphology. Three adaptive markers were strongly associated with morphology, and one marker also correlated with upstream migration distance and timing. Genes physically linked with these markers plausibly influence differences in body size, which is also consistently associated with migration distance in Pacific lamprey. Pacific lamprey conservation implications include the potential to predict an individual's upstream destination based on its genotype. More broadly, the results suggest a genetic basis for intrapopulation variation in migration distance in migratory species. PMID:25558280

  12. 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...of sizing systems. The impact of these changes are (as theoretically demonstrated here) that legacy size charts, based on the ANSUR 1988 data, would

  13. Demands of eicosapentaenoic acid (EPA) in Daphnia: are they dependent on body size?

    PubMed

    Sikora, Anna B; Petzoldt, Thomas; Dawidowicz, Piotr; von Elert, Eric

    2016-10-01

    Fatty acids contribute to the nutritional quality of the phytoplankton and, thus, play an important role in Daphnia nutrition. One of the polyunsaturated fatty acids (PUFAs)--eicosapentaenoic acid (EPA)--has been shown to predict carbon transfer between primary producers and consumers in lakes, suggesting that EPA limitation of Daphnia in nature is widespread. Although the demand for EPA must be covered by the diet, the demand of EPA in Daphnia that differ in body size has not been addressed yet. Here, we hypothesize that the demand for EPA in Daphnia is size-dependent and that bigger species have a higher EPA demand. To elucidate this, a growth experiment was conducted in which at 20 °C three Daphnia taxa (small-sized D. longispina complex, medium-sized D. pulicaria, and large-bodied D. magna) were fed Synechococcus elongatus supplemented with cholesterol and increasing concentrations of EPA. In addition, fatty acid analyses of Daphnia were performed. Our results show that the saturation threshold for EPA-dependent growth increased with increasing body size. This increase in thresholds with body size may provide another mechanism contributing to the prevalence of small-bodied cladocera in warm habitats and to the midsummer decline of large cladocera in eutrophic water bodies.

  14. Body dysmorphic disorder: A complex and polymorphic affection

    PubMed Central

    Fiori, Patrizia; Giannetti, Luigi Maria

    2009-01-01

    Background Body dysmorphic disorder (BDD) is defined as a syndrome characterized by an excessive preoccupation because of a presumed or minimal physical flaw in appearance that polarizes the energies of the subject. So far, its specular aspect, represented by the presence of an evident physical defect that is not recognized or is even denied and neglected, has been disregarded. The aim of our study was to examine the individual and relational meaning of BDD and to evaluate the efficacy of cognitive-behavioral and medical–aesthetical treatments. Methods and results We describe two subjects with BDD, diagnosed by clinical interviews and test. Both patients were compliant to cognitive-behavioral approach. One out of two subjects underwent aesthetical treatments. Conclusions Cognitive-behavioral therapy stimulates self-consciousness, rebuilds the body image, promotes health care, and improves relational capacity. Moreover, it ensures the success of any medical and/or surgical procedures by preventing unrealistic expectations. Lastly, it contributes to the definition of worldwide shared behavioral models. PMID:19777069

  15. Effect of Individual Variability in Body Size on Empirical Model Predictions of Exercise Endurance Times

    DTIC Science & Technology

    2005-05-01

    clothing, and exertion, increased body mass index ( BMI ) has recently been shown to increase the likelihood of developing exertional heat illness. USARIEM...addition to weather, clothing, and exertion, increased body mass index ( BMI ) has recently been shown to increase the likelihood of developing exertional...OF ABSTRACT 8. M05-24 1. AGENCY USE ONLY (Leave blank) 4. TITLE AND SUBTITLE EFFECT OF INDIVIDUAL VARIABILITY IN BODY SIZE ON EMPIRICAL MODEL

  16. Determinants and consequences of interspecific body size variation in tetraphyllidean tapeworms.

    PubMed

    Randhawa, Haseeb Sajjad; Poulin, Robert

    2009-10-01

    Tetraphyllidean cestodes are cosmopolitan, remarkably host specific, and form the most speciose and diverse group of helminths infecting elasmobranchs (sharks, skates and rays). They show substantial interspecific variation in a variety of morphological traits, including body size. Tetraphyllideans represent therefore, an ideal group in which to examine the relationship between parasite body size and abundance. The individual and combined effects of host size, environmental temperature, host habitat, host environment, host physiology, and host type (all likely correlates of parasite body size) on parasite length were assessed using general linear model analyses using data from 515 tetraphyllidean cestode species (182 species were included in analyses). The relationships between tetraphyllidean cestode length and intensity and abundance of infection were assessed using simple linear regression analyses. Due to the contrasting morphologies between shark and batoid hosts, and contrasting physiologies between sharks of the Lamnidae family and other sharks, analyses were repeated in different subsets based on host morphology and physiologies ("sharks" vs. batoids) to determine the influence of these variables on adult tetraphyllidean tapeworm body size. Results presented herein indicate that host body size, environmental temperature and host habitat are relatively important variables in models explaining interspecific variations in tetraphyllidean tapeworm length. In addition, a negative relationship between tetraphyllidean body size and intensity of infection was apparent. These results suggest that space constraints and ambient temperature, via their effects on metabolism and growth, determine adult tetraphyllidean cestode size. Consequently, a trade-off between size and numbers is possibly imposed by external forces influencing host size, hence limiting physical space or other resources available to the parasites.

  17. Venom yield and its relationship with body size and fang separation of pit vipers from Argentina.

    PubMed

    de Roodt, Adolfo Rafael; Boyer, Leslie Victoria; Lanari, Laura Cecilia; Irazu, Lucia; Laskowicz, Rodrigo Daniel; Sabattini, Paula Leticia; Damin, Carlos Fabián

    2016-10-01

    The amount of venom that a snake can inject is related to its body size. The body size is related to head size and to the distance between fangs. To correlate snake body size, distance between fangs and distance between puncture wounds with the venom yield (and consequently with the venom dose potentially injected in a single snakebite), we studied these variables in two species of public health importance in South America, Bothrops (Rhinocerophis) alternatus, and Crotalus durissus terrificus. In all cases a positive correlation was observed between body length, fang separation distance, distance between puncture wounds and venom yield, with a regression coefficient over 0.5 for Bothrops alternatus and over 0.6 for Crotalus durissus terrificus in all cases, being the relation distance between punctures wounds and venom yield of 0.54 and 0.69 respectively. The difference between fang separation and puncture separation was never greater than 30%, with a mean difference around 13%. The strong relationships between body size, fang separation and venom yield may be useful for planning potential venom production in serpentariums. In addition, because puncture mark separation gives an approximate idea of the size of the snake, this provides a rough idea of the size of the snake that produced a bite and the potential amount of venom that could have been injected.

  18. Global warming and Bergmann's rule: do central European passerines adjust their body size to rising temperatures?

    PubMed

    Salewski, Volker; Hochachka, Wesley M; Fiedler, Wolfgang

    2010-01-01

    Recent climate change has caused diverse ecological responses in plants and animals. However, relatively little is known about homeothermic animals' ability to adapt to changing temperature regimes through changes in body size, in accordance with Bergmann's rule. We used fluctuations in mean annual temperatures in south-west Germany since 1972 in order to look for direct links between temperature and two aspects of body size: body mass and flight feather length. Data from regionally born juveniles of 12 passerine bird species were analysed. Body mass and feather length varied significantly among years in eight and nine species, respectively. Typically the inter-annual changes in morphology were complexly non-linear, as was inter-annual variation in temperature. For six (body mass) and seven species (feather length), these inter-annual fluctuations were significantly correlated with temperature fluctuations. However, negative correlations consistent with Bergmann's rule were only found for five species, either for body mass or feather length. In several of the species for which body mass and feather length was significantly associated with temperature, morphological responses were better predicted by temperature data that were smoothed across multiple years than by the actual mean breeding season temperatures of the year of birth. This was found in five species for body mass and three species for feather length. These results suggest that changes in body size may not merely be the result of phenotypic plasticity but may hint at genetically based microevolutionary adaptations.

  19. Climate change impacts on body size and food web structure on mountain ecosystems.

    PubMed

    Lurgi, Miguel; López, Bernat C; Montoya, José M

    2012-11-05

    The current distribution of climatic conditions will be rearranged on the globe. To survive, species will have to keep pace with climates as they move. Mountains are among the most affected regions owing to both climate and land-use change. Here, we explore the effects of climate change in the vertebrate food web of the Pyrenees. We investigate elevation range expansions between two time-periods illustrative of warming conditions, to assess: (i) the taxonomic composition of range expanders; (ii) changes in food web properties such as the distribution of links per species and community size-structure; and (iii) what are the specific traits of range expanders that set them apart from the other species in the community-in particular, body mass, diet generalism, vulnerability and trophic position within the food web. We found an upward expansion of species at all elevations, which was not even for all taxonomic groups and trophic positions. At low and intermediate elevations, predator : prey mass ratios were significantly reduced. Expanders were larger, had fewer predators and were, in general, more specialists. Our study shows that elevation range expansions as climate warms have important and predictable impacts on the structure and size distribution of food webs across space.

  20. Climate change impacts on body size and food web structure on mountain ecosystems

    PubMed Central

    Lurgi, Miguel; López, Bernat C.; Montoya, José M.

    2012-01-01

    The current distribution of climatic conditions will be rearranged on the globe. To survive, species will have to keep pace with climates as they move. Mountains are among the most affected regions owing to both climate and land-use change. Here, we explore the effects of climate change in the vertebrate food web of the Pyrenees. We investigate elevation range expansions between two time-periods illustrative of warming conditions, to assess: (i) the taxonomic composition of range expanders; (ii) changes in food web properties such as the distribution of links per species and community size-structure; and (iii) what are the specific traits of range expanders that set them apart from the other species in the community—in particular, body mass, diet generalism, vulnerability and trophic position within the food web. We found an upward expansion of species at all elevations, which was not even for all taxonomic groups and trophic positions. At low and intermediate elevations, predator : prey mass ratios were significantly reduced. Expanders were larger, had fewer predators and were, in general, more specialists. Our study shows that elevation range expansions as climate warms have important and predictable impacts on the structure and size distribution of food webs across space. PMID:23007094

  1. Arctic ecosystem structure and functioning shaped by climate and herbivore body size

    NASA Astrophysics Data System (ADS)

    Legagneux, P.; Gauthier, G.; Lecomte, N.; Schmidt, N. M.; Reid, D.; Cadieux, M.-C.; Berteaux, D.; Bêty, J.; Krebs, C. J.; Ims, R. A.; Yoccoz, N. G.; Morrison, R. I. G.; Leroux, S. J.; Loreau, M.; Gravel, D.

    2014-05-01

    Significant progress has been made in our understanding of species-level responses to climate change, but upscaling to entire ecosystems remains a challenge. This task is particularly urgent in the Arctic, where global warming is most pronounced. Here we report the results of an international collaboration on the direct and indirect effects of climate on the functioning of Arctic terrestrial ecosystems. Our data from seven terrestrial food webs spread along a wide range of latitudes (~1,500 km) and climates (Δ mean July temperature = 8.5 °C) across the circumpolar world show the effects of climate on tundra primary production, food-web structure and species interaction strength. The intensity of predation on lower trophic levels increased significantly with temperature, at approximately 4.5% per °C. Temperature also affected trophic interactions through an indirect effect on food-web structure (that is, diversity and number of interactions). Herbivore body size was a major determinant of predator-prey interactions, as interaction strength was positively related to the predator-prey size ratio, with large herbivores mostly escaping predation. There is potential for climate warming to cause a switch from bottom-up to top-down regulation of herbivores. These results are critical to resolving the debate on the regulation of tundra and other terrestrial ecosystems exposed to global change.

  2. How do respiratory state and measurement method affect bra size calculations?

    PubMed Central

    McGhee, D E; Steele, J R

    2006-01-01

    Objectives To investigate the effects of respiratory state and measurement method on bra size calculation. Methods The bra sizes of 16 large‐breasted women were measured during two respiratory states, end voluntary inspiration and relaxed voluntary expiration, and using two sizing methods, which were compared against subject‐reported bra sizes. Results Both respiratory state and measurement method significantly affected bra size estimations, whereby measuring chest circumference during inspiration increased both band and decreased cup size. However, whereas bra size calculated using the standard method differed significantly from subject‐reported bra size, cup size calculated using the breast hemi‐circumference method did not differ significantly from subject‐reported cup size. Conclusions As respiratory state significantly affects bra sizes, it should be standardised during bra size measurements. A more valid and reliable bra sizing method should be developed, possibly using the breast hemi‐circumference method for cup size estimations and raw under‐bust chest circumference values for band size. PMID:17021004

  3. Seasonal variation in metabolic rate, flight activity and body size of Anopheles gambiae in the Sahel

    PubMed Central

    Huestis, Diana L.; Yaro, Alpha S.; Traoré, Adama I.; Dieter, Kathryne L.; Nwagbara, Juliette I.; Bowie, Aleah C.; Adamou, Abdoulaye; Kassogué, Yaya; Diallo, Moussa; Timbiné, Seydou; Dao, Adama; Lehmann, Tovi

    2012-01-01

    SUMMARY Malaria in Africa is vectored primarily by the Anopheles gambiae complex. Although the mechanisms of population persistence during the dry season are not yet known, targeting dry season mosquitoes could provide opportunities for vector control. In the Sahel, it appears likely that M-form A. gambiae survive by aestivation (entering a dormant state). To assess the role of eco-physiological changes associated with dry season survival, we measured body size, flight activity and metabolic rate of wild-caught mosquitoes throughout 1 year in a Sahelian locality, far from permanent water sources, and at a riparian location adjacent to the Niger River. We found significant seasonal variation in body size at both the Sahelian and riparian sites, although the magnitude of the variation was greater in the Sahel. For flight activity, significant seasonality was only observed in the Sahel, with increased flight activity in the wet season when compared with that just prior to and throughout the dry season. Whole-organism metabolic rate was affected by numerous biotic and abiotic factors, and a significant seasonal component was found at both locations. However, assay temperature accounted completely for seasonality at the riparian location, while significant seasonal variation remained after accounting for all measured variables in the Sahel. Interestingly, we did not find that mean metabolic rate was lowest during the dry season at either location, contrary to our expectation that mosquitoes would conserve energy and increase longevity by reducing metabolism during this time. These results indicate that mosquitoes may use mechanisms besides reduced metabolic rate to enable survival during the Sahelian dry season. PMID:22623189

  4. The effects of food shortage during larval development on adult body size, body mass, physiology and developmental time in a tropical damselfly.

    PubMed

    Jiménez-Cortés, J Guillermo; Serrano-Meneses, Martín Alejandro; Córdoba-Aguilar, Alex

    2012-03-01

    Few studies have looked jointly at the effects of larval stressors on life history and physiology across metamorphosis, especially in tropical insects. Here we investigated how the variation of food availability during the larval stage of the tropical and territorial American rubyspot damselfly (Hetaerina americana) affects adult body size and body mass, and two physiological indicators of condition--phenoloxidase activity (an indicator of immune ability) and protein concentration. We also investigated whether larval developmental time is prolonged when food is scarce, an expected situation for tropical species whose larval time is less constrained, compared to temperate species. Second instar larvae were collected from their natural environments and reared in one of two diet regimes: (i) "rich" provided with five Artemia salina prey every day, and (ii) "poor" provided with two A. salina prey every day. In order to compare how distinct our treatments were from natural conditions, a second set of last-instar larvae were also collected and allowed to emerge. Only body size and phenoloxidase increased in the rich regime, possibly to prioritize investment on sexually selected traits (which increase mating opportunities), and immune ability, given pathogen pressure. The sexes did not differ in body size in relation to food regimes but they did differ in body mass and protein concentration; this can be explained on the basis of the energetically demanding territorial activities by males (for the case of body mass), and female allocation to egg production (for the case of protein). Finally, animals delayed larval development when food was scarce, which is coherent for tropical environments. These findings provide key insights in the role of food availability in a tropical species.

  5. Body Size Reductions in Nonmammalian Eutheriodont Therapsids (Synapsida) during the End-Permian Mass Extinction

    PubMed Central

    Huttenlocker, Adam K.

    2014-01-01

    The extent to which mass extinctions influence body size evolution in major tetrapod clades is inadequately understood. For example, the ‘Lilliput effect,’ a common feature of mass extinctions, describes a temporary decrease in body sizes of survivor taxa in post-extinction faunas. However, its signature on existing patterns of body size evolution in tetrapods and the persistence of its impacts during post-extinction recoveries are virtually unknown, and rarely compared in both geologic and phylogenetic contexts. Here, I evaluate temporal and phylogenetic distributions of body size in Permo-Triassic therocephalian and cynodont therapsids (eutheriodonts) using a museum collections-based approach and time series model fitting on a regional stratigraphic sequence from the Karoo Basin, South Africa. I further employed rank order correlation tests on global age and clade rank data from an expanded phylogenetic dataset, and performed evolutionary model testing using Brownian (passive diffusion) models. Results support significant size reductions in the immediate aftermath of the end-Permian mass extinction (ca. 252.3 Ma) consistent with some definitions of Lilliput effects. However, this temporal succession reflects a pattern that was underscored largely by Brownian processes and constructive selectivity. Results also support two recent contentions about body size evolution and mass extinctions: 1) active, directional evolution in size traits is rare over macroevolutionary time scales and 2) geologically brief size reductions may be accomplished by the ecological removal of large-bodied species without rapid originations of new small-bodied clades or shifts from long-term evolutionary patterns. PMID:24498335

  6. Body image and body type preferences in St. Kitts, Caribbean: a cross- cultural comparison with U.S. samples regarding attitudes towards muscularity, body fat, and breast size.

    PubMed

    Gray, Peter B; Frederick, David A

    2012-09-06

    We investigated body image in St. Kitts, a Caribbean island where tourism, international media, and relatively high levels of body fat are common. Participants were men and women recruited from St. Kitts (n = 39) and, for comparison, U.S. samples from universities (n = 618) and the Internet (n = 438). Participants were shown computer generated images varying in apparent body fat level and muscularity or breast size and they indicated their body type preferences and attitudes. Overall, there were only modest differences in body type preferences between St. Kitts and the Internet sample, with the St. Kitts participants being somewhat more likely to value heavier women. Notably, however, men and women from St. Kitts were more likely to idealize smaller breasts than participants in the U.S. samples. Attitudes regarding muscularity were generally similar across samples. This study provides one of the few investigations of body preferences in the Caribbean.

  7. Caterpillars selected for large body size and short development time are more susceptible to oxygen-related stress

    PubMed Central

    Harrison, Jon F; Cease, Arianne J; VandenBrooks, John M; Albert, Todd; Davidowitz, Goggy

    2013-01-01

    Recent studies suggest that higher growth rates may be associated with reduced capacities for stress tolerance and increased accumulated damage due to reactive oxygen species. We tested the response of Manduca sexta (Sphingidae) lines selected for large or small body size and short development time to hypoxia (10 kPa) and hyperoxia (25, 33, and 40 kPa); both hypoxia and hyperoxia reduce reproduction and oxygen levels over 33 kPa have been shown to increase oxidative damage in insects. Under normoxic (21 kPa) conditions, individuals from the large-selected (big-fast) line were larger and had faster growth rates, slightly longer developmental times, and reduced survival rates compared to individuals from a line selected for small size (small-fast) or an unselected control line. Individuals from the big-fast line exhibited greater negative responses to hyperoxia with greater reductions in juvenile and adult mass, growth rate, and survival than the other two lines. Hypoxia generally negatively affected survival and growth/size, but the lines responded similarly. These results are mostly consistent with the hypothesis that simultaneous acquisition of large body sizes and short development times leads to reduced capacities for coping with stressful conditions including oxidative damage. This result is of particular importance in that natural selection tends to decrease development time and increase body size. PMID:23762517

  8. Weber's Illusion and Body Shape: Anisotropy of Tactile Size Perception on the Hand

    ERIC Educational Resources Information Center

    Longo, Matthew R.; Haggard, Patrick

    2011-01-01

    The perceived distance between touches on a single skin surface is larger on regions of high tactile sensitivity than those with lower acuity, an effect known as "Weber's illusion". This illusion suggests that tactile size perception involves a representation of the perceived size of body parts preserving characteristics of the somatosensory…

  9. A critical evaluation of the insect body size model and causes of metamorphosis in solitary bees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The insect body size model posits that adult size is determined by growth rate and the duration of growth during the larval stage of development. Within the model, growth rate is regulated by many mechanistic elements that are influenced by both internal and external factors. However, the duration o...

  10. Age modifies effect of body size on fecundity in Culex quinquefasciatus Say (Diptera: Culicidae).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fecundity of mosquitoes can vary with many factors, and can have a strong effect on population growth. This study reports the effects of body size, blood meal size and age on reproductive output of nulliparous Culex quinquefasciatus, a vector of arboviruses and other pathogens. Mated adult female m...

  11. Male lifetime mating success in relation to body size in Diabrotica barberi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Body size is often an important component of male lifetime mating success in insects, especially when males are capable of mating several times over their lifespan. We paired either a large or small male northern corn rootworm with a female of random size and noted copulation success. We observed co...

  12. Relationships between body size and percent body fat among Melanesians in Vanuatu.

    PubMed

    Dancause, Kelsey Needham; Vilar, Miguel; DeHuff, Christa; Wilson, Michelle; Soloway, Laura E; Chan, Chim; Lum, J Koji; Garruto, Ralph M

    2010-01-01

    Obesity is a global epidemic, and measures to define it must be appropriate for diverse populations for accurate assessment of worldwide risk. Obesity refers to excess body fatness, but is more commonly defined by body mass index (BMI). Body composition varies among populations: Asians have higher percent body fat (%BF), and Pacific Islanders lower %BF at a given BMI compared to Europeans. Many researchers thus propose higher BMI cut-off points for obesity among Pacific Islanders and lower cut-offs for Asians. Because of the great genetic diversity in the Asia-Pacific region, more studies analyzing associations between BMI and %BF among diverse populations remain necessary. We measured height; weight; tricep, subscapular, and suprailiac skinfolds; waist and hip circumference; and %BF by bioelectrical impedance among 546 adult Melanesians from Vanuatu in the South Pacific. We analyzed relationships among anthropometric measurements and compared them to measurements from other populations in the Asia-Pacific region. BMI was a relatively good predictor of %BF among our sample. Based on regression analyses, the BMI value associated with obesity defined by %BF (>25% for men, >35% for women) at age 40 was 27.9 for men and 27.8 for women. This indicates a need for a more nuanced definition of obesity than provided by the common BMI cut-off value of 30. Rather than using population-specific cut-offs for Pacific Islanders, we suggest the World Health Organization's public health action cut-off points (23, 27.5, 32.5, 37.5), which enhance the precision of assessments of population-wide obesity burdens while still allowing for international comparison.

  13. Body Size Versus Depth: Regional and Taxonomical Variation in Deep-Sea Meio- and Macrofaunal Organisms.

    PubMed

    van der Grient, Jesse M A; Rogers, Alex D

    2015-01-01

    Body size (weight per individual) is an important concept in ecology. It has been studied in the deep sea where a decrease in size with increasing depth has often been found. This has been explained as an adaptation to food limitation where size reduction results in a lowered metabolic rate and a decreased energetic requirement. However, observations vary, with some studies showing an increase in size with depth, and some finding no depth correlation at all. Here, we collected data from peer-reviewed studies on macro- and meiofaunal abundance and biomass, creating two datasets allowing statistical comparison of factors expected to influence body size in meio- and macrofaunal organisms. Our analyses examined the influence of region, taxonomic group and sampling method on the body size of meiofauna and macrofauna in the deep sea with increasing depth, and the resulting models are presented. At the global scale, meio- and macrofaunal communities show a decrease in body size with increasing depth as expected with the food limitation hypothesis. However, at the regional scale there were differences in trends of body size with depth, either showing a decrease (e.g. southwest Pacific Ocean; meio- and macrofauna) or increase (e.g. Gulf of Mexico; meiofauna only) compared to a global mean. Taxonomic groups also showed differences in body size trends compared to total community average (e.g. Crustacea and Bivalvia). Care must be taken when conducting these studies, as our analyses indicated that sampling method exerts a significant influence on research results. It is possible that differences in physiology, lifestyle and life history characteristics result in different responses to an increase in depth and/or decrease in food availability. This will have implications in the future as food supply to the deep sea changes as a result of climate change (e.g. increased ocean stratification at low to mid latitudes and reduced sea ice duration at high latitudes).

  14. Heterogeneous hosts: how variation in host size, behaviour and immunity affects parasite aggregation.

    PubMed

    Johnson, Pieter T J; Hoverman, Jason T

    2014-09-01

    Infection heterogeneity is one of the most fundamental patterns in disease ecology, yet surprisingly few studies have experimentally explored its underlying drivers. Here, we used large-scale field assessments to evaluate the degree of parasite aggregation within amphibian host populations followed by a novel experimental approach to assess the potential influence of host size, behaviour and immunity in reproducing such heterogeneity. Among 227 wetlands, 2468 hosts and seven parasite species, infections were consistently aggregated among host individuals within populations of the Pacific chorus frog (Pseudacris regilla). For each parasite species, the relationship between the log-mean and log-variance of infection load was strongly linear (R(2): 0·91-0·98) with a slope between 1·37 and 1·67, indicative of aggregation relative to the expected Poisson slope of unity. In laboratory trials with P. regilla and the most virulent trematode (Ribeiroia ondatrae), experimental reductions in either host immunity (through corticosterone exposure) or antiparasite behaviours (through anaesthesia exposure) increased parasite infection loads in isolated hosts by 62-102% relative to unmanipulated individuals. In a second experiment designed to test how variation in host immunity, behaviour and body size affected variation in infection load within small groups (dyads), a reduction in immune function or behaviour of one host significantly amplified infection heterogeneity within the group, effectively doubling the variance-to-mean ratio. However, immunity affected aggregation only in the absence of behavioural manipulation, and changing the size distribution of hosts did not appreciably affect aggregation. Using Taylor's Power Law to integrate field and laboratory data, we found that only treatments involving behavioural reductions achieved aggregation levels comparable to natural host populations. Thus, despite their short duration, our treatments generated heterogeneity in

  15. Variations in leopard cat (Prionailurus bengalensis) skull morphology and body size: sexual and geographic influences

    PubMed Central

    Oliveira, Luiz Flamarion B.

    2015-01-01

    foot of male leopard cats is the main feature of sexual dimorphism among P. b. bengalensis (and probably among P. b. horsfieldii too). External body measurements also indicated the absence of sexual dimorphism among individuals of P. b. borneoensis. Inter-subspecific skull comparisons provided a morphometric basis for differentiating some subspecies. Prionailurus b. horsfieldii and P. b. bengalensis were distinguished only by a subtle difference in PM4 size, indicating that overall skull morphology does not appear to support their separate taxonomical status, in spite of the marked differences reported in their coat patterns. Geological events affecting the Sunda Shelf connection between the Sunda Islands and the mainland during the Last Glacial Maximum seem to have influenced directly the morphological pattern shown by leopard cat subspecies nowadays. PMID:26500818

  16. Interdependent effects of male and female body size plasticity on mating behaviour of predatory mites

    PubMed Central

    Walzer, Andreas; Schausberger, Peter

    2015-01-01

    The adaptive canalization hypothesis predicts that traits with low phenotypic plasticity are more fitness relevant, because they have been canalized via strong past selection, than traits with high phenotypic plasticity. Based on differing male body size plasticities of the predatory mites Phytoseiulus persimilis (low plasticity) and Neoseiulus californicus (high plasticity), we accordingly hypothesized that small male body size entails higher costs in female choice and male–male competition in P. persimilis than N. californicus. Males of both species are highly polygynous but females differ in the level of polyandry (low level in P. persimilis; medium level in N. californicus). We videotaped the mating interactions in triplets of either P. persimilis or N. californicus, consisting of a virgin female (small or standard-sized) and a small and a standard-sized male. Mating by both small and standard-sized P. persimilis females was biased towards standard-sized males, resulting from the interplay between female preference for standard-sized males and the inferiority of small males in male–male competition. In contrast, mating by N. californicus females was equally balanced between small and standard-sized males. Small N. californicus males were more aggressive (‘Napoleon complex’) in male–male competition, reducing the likelihood of encounter between the standard-sized male and the female, and thus counterbalancing female preference for standard-sized males. Our results support the hypothesis that male body size is more important to fitness in the low-level polyandrous P. persimilis than in the medium-level polyandrous N. californicus and provide a key example of the implications of sexually selected body size plasticity on mating behaviour. PMID:25673881

  17. Body size mediated coexistence of consumers competing for resources in space

    USGS Publications Warehouse

    Basset, A.; Angelis, D.L.

    2007-01-01

    Body size is a major phenotypic trait of individuals that commonly differentiates co-occurring species. We analyzed inter-specific competitive interactions between a large consumer and smaller competitors, whose energetics, selection and giving-up behaviour on identical resource patches scaled with individual body size. The aim was to investigate whether pure metabolic constraints on patch behaviour of vagile species can determine coexistence conditions consistent with existing theoretical and experimental evidence. We used an individual-based spatially explicit simulation model at a spatial scale defined by the home range of the large consumer, which was assumed to be parthenogenic and semelparous. Under exploitative conditions, competitive coexistence occurred in a range of body size ratios between 2 and 10. Asymmetrical competition and the mechanism underlying asymmetry, determined by the scaling of energetics and patch behaviour with consumer body size, were the proximate determinant of inter-specific coexistence. The small consumer exploited patches more efficiently, but searched for profitable patches less effectively than the larger competitor. Therefore, body-size related constraints induced niche partitioning, allowing competitive coexistence within a set of conditions where the large consumer maintained control over the small consumer and resource dynamics. The model summarises and extends the existing evidence of species coexistence on a limiting resource, and provides a mechanistic explanation for decoding the size-abundance distribution patterns commonly observed at guild and community levels. ?? Oikos.

  18. Reduced body size and cub recruitment in polar bears associated with sea ice decline.

    PubMed

    Rode, Karyn D; Amstrup, Steven C; Regehr, Eric V

    2010-04-01

    Rates of reproduction and survival are dependent upon adequate body size and condition of individuals. Declines in size and condition have provided early indicators of population decline in polar bears (Ursus maritimus) near the southern extreme of their range. We tested whether patterns in body size, condition, and cub recruitment of polar bears in the southern Beaufort Sea of Alaska were related to the availability of preferred sea ice habitats and whether these measures and habitat availability exhibited trends over time, between 1982 and 2006. The mean skull size and body length of all polar bears over three years of age declined over time, corresponding with long-term declines in the spatial and temporal availability of sea ice habitat. Body size of young, growing bears declined over time and was smaller after years when sea ice availability was reduced. Reduced litter mass and numbers of yearlings per female following years with lower availability of optimal sea ice habitat, suggest reduced reproductive output and juvenile survival. These results, based on analysis of a long-term data set, suggest that declining sea ice is associated with nutritional limitations that reduced body size and reproduction in this population.

  19. Reduced body size and cub recruitment in polar bears associated with sea ice decline

    USGS Publications Warehouse

    Rode, K.D.; Amstrup, Steven C.; Regehr, E.V.

    2010-01-01

    Rates of reproduction and survival are dependent upon adequate body size and condition of individuals. Declines in size and condition have provided early indicators of population decline in polar bears (Ursus maritimus) near the southern extreme of their range. We tested whether patterns in body size, condition, and cub recruitment of polar bears in the southern Beaufort Sea of Alaska were related to the availability of preferred sea ice habitats and whether these measures and habitat availability exhibited trends over time, between 1982 and 2006. The mean skull size and body length of all polar bears over three years of age declined over time, corresponding with long-term declines in the spatial and temporal availability of sea ice habitat. Body size of young, growing bears declined over time and was smaller after years when sea ice availability was reduced. Reduced litter mass and numbers of yearlings per female following years with lower availability of optimal sea ice habitat, suggest reduced reproductive output and juvenile survival. These results, based on analysis of a longterm data set, suggest that declining sea ice is associated with nutritional limitations that reduced body size and reproduction in this population. ?? 2010 by the Ecological Society of America.

  20. Body size is not critical for critical PO₂ in scarabaeid and tenebrionid beetles.

    PubMed

    Lease, Hilary M; Klok, Cornelis J; Kaiser, Alexander; Harrison, Jon F

    2012-07-15

    Constraints on oxygen delivery potentially limit animal body size. Because diffusion rates are highly distance dependent, and because tracheal length increases with size, gas exchange was traditionally thought to be more difficult for larger insects. As yet the effect of body size on critical oxygen partial pressure (P(crit)) has not been measured for any clade of insect species for which there are interspecific data on tracheal scaling. We addressed this deficiency by measuring P(crit) over a 4150-fold mass range (ratio of largest to smallest species mean) of two families of Coleoptera (Tenebrionidae and Scarabaeidae). We exposed adult beetles to progressively lower oxygen levels and measured their ability to maintain CO(2) release rates. Absolute metabolic rates increased hypometrically with beetle body mass (M) at both normoxic (M(0.748)) and hypoxic (M(0.846)) conditions. P(crit), however, was independent of body size. Maximum overall conductances for oxygen from air to mitochondria (G(O(2),max)) matched metabolic rates as insects became larger, likely enabling the similar P(crit) values observed in large and small beetles. These data suggest that current atmospheric oxygen levels do not limit body size of insects because of limitations on gas exchange. However, increasing relative investment in the tracheal system in larger insects may produce trade-offs or meet spatial limits that constrain insect size.

  1. Waif goodbye! Average-size female models promote positive body image and appeal to consumers.

    PubMed

    Diedrichs, Phillippa C; Lee, Christina

    2011-10-01

    Despite consensus that exposure to media images of thin fashion models is associated with poor body image and disordered eating behaviours, few attempts have been made to enact change in the media. This study sought to investigate an effective alternative to current media imagery, by exploring the advertising effectiveness of average-size female fashion models, and their impact on the body image of both women and men. A sample of 171 women and 120 men were assigned to one of three advertisement conditions: no models, thin models and average-size models. Women and men rated average-size models as equally effective in advertisements as thin and no models. For women with average and high levels of internalisation of cultural beauty ideals, exposure to average-size female models was associated with a significantly more positive body image state in comparison to exposure to thin models and no models. For men reporting high levels of internalisation, exposure to average-size models was also associated with a more positive body image state in comparison to viewing thin models. These findings suggest that average-size female models can promote positive body image and appeal to consumers.

  2. Body size limits dim-light foraging activity in stingless bees (Apidae: Meliponini).

    PubMed

    Streinzer, Martin; Huber, Werner; Spaethe, Johannes

    2016-10-01

    Stingless bees constitute a species-rich tribe of tropical and subtropical eusocial Apidae that act as important pollinators for flowering plants. Many foraging tasks rely on vision, e.g. spatial orientation and detection of food sources and nest entrances. Meliponini workers are usually small, which sets limits on eye morphology and thus quality of vision. Limitations are expected both on acuity, and thus on the ability to detect objects from a distance, as well as on sensitivity, and thus on the foraging time window at dusk and dawn. In this study, we determined light intensity thresholds for flight under dim light conditions in eight stingless bee species in relation to body size in a Neotropical lowland rainforest. Species varied in body size (0.8-1.7 mm thorax-width), and we found a strong negative correlation with light intensity thresholds (0.1-79 lx). Further, we measured eye size, ocelli diameter, ommatidia number, and facet diameter. All parameters significantly correlated with body size. A disproportionately low light intensity threshold in the minute Trigonisca pipioli, together with a large eye parameter P eye suggests specific adaptations to circumvent the optical constraints imposed by the small body size. We discuss the implications of body size in bees on foraging behavior.

  3. Correlation of Gulf of Mexico Nutrient Availability and Foraminiferan Body Size

    NASA Astrophysics Data System (ADS)

    Hernandez, J.; Payne, J.; Keating-Bitonti, C.

    2012-12-01

    The Island Rule states that organisms converge on an optimal body size through time. The Gulf of Mexico is surrounded by land, which allows the organisms to retain similar amounts of nutrients. We hypothesis that organisms living in the Gulf of Mexico will not show size difference. This study focuses on nutrient availability and benthic foraminiferal body size distributions. Foraminifera are single-celled marine organisms that are an excellent recorder of the environment. An ANOVA statistical test was done to see if foram body size varied with our different independent variables. We did not observe a significant difference in the body size of benthic foraminifera between those living in the shallow water and those in the deep basin in the Gulf of Mexico. Our results suggest that benthic foraminifera in the Gulf of Mexico receive a greater amount of nutrients because it is surrounded by land. Overall, our prediction to this study tested out to be true because the organisms showed no significant change on the body size.

  4. Temperature and body weight affect fouling of pig pens.

    PubMed

    Aarnink, A J A; Schrama, J W; Heetkamp, M J W; Stefanowska, J; Huynh, T T T

    2006-08-01

    Fouling of the solid lying area in pig housing is undesirable for reasons of animal welfare, animal health, environmental pollution, and labor costs. In this study the influence of temperature on the excreting and lying behavior of growing-finishing pigs of different BW (25, 45, 65, 85, or 105 kg) was studied. Ten groups of 5 pigs were placed in partially slatted pens (60% solid concrete, 40% metal-slatted) in climate respiration chambers. After an adaptation period, temperatures were raised daily for 9 d. Results showed that above certain inflection temperatures (IT; mean 22.6 degrees C, SE = 0.78) the number of excretions (relative to the total number of excretions) on the solid floor increased with temperature (mean increase 9.7%/ degrees C, SE = 1.41). Below the IT, the number of excretions on the solid floor was low and not influenced by temperature (mean 13.2%, SE = 3.5). On average, the IT for excretion on the solid floor decreased with increasing BW, from approximately 25 degrees C at 25 kg to 20 degrees C at 100 kg of BW (P < 0.05). Increasing temperature also affected the pattern and postural lying. The temperature at which a maximum number of pigs lay on the slatted floor (i.e., the IT for lying) decreased from approximately 27 degrees C at 25 kg to 23 degrees C at 100 kg of BW (P < 0.001). At increasing temperatures, pigs lay more on their sides and less against other pigs (P < 0.001). Temperature affects lying and excreting behavior of growing-finishing pigs in partially slatted pens. Above certain IT, pen fouling increases linearly with temperature. Inflection temperatures decrease at increasing BW.

  5. Evolution of large body size in abalones (Haliotis): Patterns and implications

    USGS Publications Warehouse

    Estes, J.A.; Lindberg, D.R.; Wray, C.

    2005-01-01

    Kelps and other fleshy macroalgae - dominant reef-inhabiting organisms in cool - seasmay have radiated extensively following late Cenozoic polar cooling, thus triggering a chain of evolutionary change in the trophic ecology of nearshore temperate ecosystems. We explore this hypothesis through an analysis of body size in the abalones (Gastropoda; Haliotidae), a widely distributed group in modern oceans that displays a broad range of body sizes and contains fossil representatives from the late Cretaceous (60-75 Ma). Geographic analysis of maximum shell length in living abalones showed that small-bodied species, while most common in the Tropics, have a cosmopolitan distribution, whereas large-bodied species occur exclusively in cold-water ecosystems dominated by kelps and other macroalgae. The phylogeography of body size evolution in extant abalones was assessed by constructing a molecular phylogeny in a mix of large and small species obtained from different regions of the world. This analysis demonstrates that small body size is the plesiomorphic state and largeness has likely arisen at least twice. Finally, we compiled data on shell length from the fossil record to determine how (slowly or suddenly) and when large body size arose in the abalones. These data indicate that large body size appears suddenly at the Miocene/Pliocene boundary. Our findings support the view that fleshy-algal dominated ecosystems radiated rapidly in the coastal oceans with the onset of the most recent glacial age. We conclude with a discussion of the broader implications of this change. ?? 2005 The Paleontological Society. All rights reserved.

  6. Body-size reduction in vertebrates following the end-Devonian mass extinction.

    PubMed

    Sallan, Lauren; Galimberti, Andrew K

    2015-11-13

    Following the end-Devonian mass extinction (359 million years ago), vertebrates experienced persistent reductions in body size for at least 36 million years. Global shrinkage was not related to oxygen or temperature, which suggests that ecological drivers played a key role in determining the length and direction of size trends. Small, fast-breeding ray-finned fishes, sharks, and tetrapods, most under 1 meter in length from snout to tail, radiated to dominate postextinction ecosystems and vertebrae biodiversity. The few large-bodied, slow-breeding survivors failed to diversify, facing extinction despite earlier evolutionary success. Thus, the recovery interval resembled modern ecological successions in terms of active selection on size and related life histories. Disruption of global vertebrate, and particularly fish, biotas may commonly lead to widespread, long-term reduction in body size, structuring future biodiversity.

  7. Body sizes in print media: Are there ethnic differences? A brief report.

    PubMed

    Shoneye, C; Johnson, F; Croker, H; Steptoe, A; Wardle, J

    2011-09-01

    There is evidence that black women are more satisfied with their body size despite higher rates of overweight. One possible mechanism is differential exposure to ultrathin images. We hypothesized that models in magazines aimed at black women are not as thin as models in materials aimed at the general population. Pictures of women from magazines aimed at black women and magazines aimed at the general population were compared (N=51). Female raters (21 white, 21 black) matched pictures to one of four drawings depicting very thin to normal-weight women. The mean body size of pictures from black magazines was significantly higher than for general magazines (p<0.001, d=0.89); 85% of pictures from general magazines were in the two thinnest size categories compared with 46% of pictures from black magazines. Media aimed at black women are less likely to use extremely slim models, which could contribute to or reflect a greater range of acceptable body sizes.

  8. Listening-touch, Affect and the Crafting of Medical Bodies through Percussion

    PubMed Central

    2015-01-01

    The growing abundance of medical technologies has led to laments over doctors’ sensory de-skilling, technologies viewed as replacing diagnosis based on sensory acumen. The technique of percussion has become emblematic of the kinds of skills considered lost. While disappearing from wards, percussion is still taught in medical schools. By ethnographically following how percussion is taught to and learned by students, this article considers the kinds of bodies configured through this multisensory practice. I suggest that three kinds of bodies arise: skilled bodies; affected bodies; and resonating bodies. As these bodies are crafted, I argue that boundaries between bodies of novices and bodies they learn from blur. Attending to an overlooked dimension of bodily configurations in medicine, self-perception, I show that learning percussion functions not only to perpetuate diagnostic craft skills but also as a way of knowing of, and through, the resource always at hand; one’s own living breathing body. PMID:27390549

  9. Relationship between self-discrepancy and worries about penis size in men with body dysmorphic disorder.

    PubMed

    Veale, David; Miles, Sarah; Read, Julie; Bramley, Sally; Troglia, Andrea; Carmona, Lina; Fiorito, Chiara; Wells, Hannah; Wylie, Kevan; Muir, Gordon

    2016-06-01

    We explored self-discrepancy in men with body dysmorphic disorder (BDD) concerned about penis size, men without BDD but anxious about penis size, and controls. Men with BDD (n=26) were compared to those with small penis anxiety (SPA; n=31) and controls (n=33), objectively (by measuring) and investigating self-discrepancy: actual size, ideal size, and size they felt they should be according to self and other. Most men under-estimated their penis size, with the BDD group showing the greatest discrepancy between perceived and ideal size. The SPA group showed a larger discrepancy than controls. This was replicated for the perceptions of others, suggesting the BDD group internalised the belief that they should have a larger penis size. There was a significant correlation between symptoms of BDD and this discrepancy. This self-actual and self-ideal/self-should discrepancy and the role of comparing could be targeted in therapy.

  10. Predictable modification of body size and competitive ability following a host shift by a seed beetle.

    PubMed

    Messina, Frank J

    2004-12-01

    Interfertile populations of the seed beetle Callosobruchus maculatus differ genetically in several behavioral, morphological, and life-history traits, including traits that affect the intensity of larval competition within seeds. Previous studies have suggested that this variation depends on differences in host size. I performed a selection experiment in which replicate beetle lines were either maintained on a small, ancestral host (mung bean) or switched to a larger, novel host (cowpea). After 40 generations, I estimated survival, development time, and adult mass on each host, both in the presence and absence of larval competition. The shift to cowpea substantially reduced body size; irrespective of rearing host, adults from the cowpea lines were more than 10% lighter than those from the mung bean lines. Switching to cowpea also improved survival and reduced development time on this host, but without decreasing performance on the ancestral host. The most striking effect of the shift to a larger host was a reduction in larval competitiveness. When two even-aged larvae co-existed within a seed, the probability that both survived to adult emergence was > or = 65% if larvae were from the cowpea lines but < or = 12% if they were from the mung bean lines. The adverse effects of competition on development time and adult mass were also less severe in the cowpea lines than in the mung bean lines. By rapidly evolving smaller size and reduced competitiveness, the cowpea lines converged toward populations chronically associated with cowpea. These results suggest that evolutionary trajectories can be predictable, and that host-specific selection can play a major role in the diversification of insect life histories. Because host shifts by small, endophagous insects are comparable to the colonization of new habitats, adaptive responses may often include traits (such as larval competitiveness) that are not directly related to host use.

  11. The non-linear relationship between body size and function in parrotfishes

    NASA Astrophysics Data System (ADS)

    Lokrantz, J.; Nyström, M.; Thyresson, M.; Johansson, C.

    2008-12-01

    Parrotfishes are a group of herbivores that play an important functional role in structuring benthic communities on coral reefs. Increasingly, these fish are being targeted by fishermen, and resultant declines in biomass and abundance may have severe consequences for the dynamics and regeneration of coral reefs. However, the impact of overfishing extends beyond declining fish stocks. It can also lead to demographic changes within species populations where mean body size is reduced. The effect of reduced mean body size on population dynamics is well described in literature but virtually no information exists on how this may influence important ecological functions. The study investigated how one important function, scraping (i.e., the capacity to remove algae and open up bare substratum for coral larval settlement), by three common species of parrotfishes ( Scarus niger, Chlorurus sordidus, and Chlorurus strongylocephalus) on coral reefs at Zanzibar (Tanzania) was influenced by the size of individual fishes. There was a non-linear relationship between body size and scraping function for all species examined, and impact through scraping was also found to increase markedly when fish reached a size of 15 20 cm. Thus, coral reefs which have a high abundance and biomass of parrotfish may nonetheless be functionally impaired if dominated by small-sized individuals. Reductions in mean body size within parrotfish populations could, therefore, have functional impacts on coral reefs that previously have been overlooked.

  12. 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.

  13. The role of body size in host specificity: reciprocal transfer experiments with feather lice.

    PubMed

    Bush, Sarah E; Clayton, Dale H

    2006-10-01

    Although most parasites show at least some degree of host specificity, factors governing the evolution of specificity remain poorly understood. Many different groups of host-specific parasites show a striking correlation between parasite and host body size, suggesting that size reinforces specificity. We tested this hypothesis by measuring the relative fitness of host-specific feather lice transferred to pigeons and doves that differ in size by an order of magnitude. To test the general influence of size, we transferred unrelated groups of wing and body lice, which are specialized for different regions of the host. Lice were transferred in both directions, from a large native host species, the rock pigeon (Columba livia), to several progressively smaller hosts, and from a small native host species, the common ground dove (Columbina passerina), to several larger hosts. We measured the relative fitness (population size) of lice transferred to these novel host species after two louse generations. Neither wing lice nor body lice could survive on novel host species that were smaller in size than the native host. However, when host defense (preening behavior) was blocked, both groups survived and reproduced on all novel hosts tested. Thus, host defense interacted with host size to govern the ability of lice to establish on small hosts. Neither wing lice nor body lice could survive on larger hosts, even when preening was blocked. In summary, host size influenced the fitness of both types of feather lice, but through different mechanisms, depending on the direction of the transfer. Our results indicate that host switching is most likely between hosts of similar body size. This finding has important implications for studies of host-parasite coevolution at both the micro- and macroevolutionary scales.

  14. Body size perception and weight control in youth: 9-year international trends from 24 countries

    PubMed Central

    Quick, Virginia; Nansel, Tonja R.; Liu, Danping; Lipsky, Leah M.; Due, Pernille; Iannotti, Ronald J.

    2014-01-01

    Objectives To examine nine-year trends and relationships regarding misperceptions of body size and dieting for weight loss among adolescents from 24 countries, and explore the influence of country-level overweight prevalence. Methods Socio-demographic characteristics, body size perception, and dieting for weight loss were assessed in the Health Behaviour in School-aged Children survey conducted in 24 countries cross-sectionally at three time points (2001/02, 2005/06, 2009/10). Logistic regression models examined change over time in overestimation of body size in non-overweight adolescents, underestimation of body size in overweight adolescents, dieting for weight loss in non-overweight and overweight adolescents, and relationships between body size perception and dieting. Analyses were stratified by weight status and sex. Covariates included country-level overweight prevalence, family affluence, and country level of development. Body mass index was only included in models examining dieting for weight loss. Results Country-level overweight prevalence increased over time (11.6% to 14.7%). Compared to Time 1, overweight adolescents had greater odds of body size underestimation at Time 3 (OR=1.68 for girls, OR=1.10 for boys), while non-overweight adolescents had lower odds of body size overestimation at Time 3 (OR=0.87 for girls, OR=0.89 for boys). Controlling for country-level overweight prevalence attenuated these relationships. Compared to Time 1, overweight and non-overweight boys were 10% more likely to diet at Time 3, while overweight and non-overweight girls were 19% and 16%, respectively, less likely to diet at Time 3. Controlling for country-level overweight prevalence did not impact trends in dieting for weight loss. Additionally, the association of self-perceived overweight with increased odds of dieting diminished over time. Conclusions Body size perceptions among adolescents may have changed over time concurrent with shifts in country-level body weight

  15. Emotional signals from faces, bodies and scenes influence observers' face expressions, fixations and pupil-size

    PubMed Central

    Kret, Mariska E.; Roelofs, Karin; Stekelenburg, Jeroen J.; de Gelder, Beatrice

    2013-01-01

    We receive emotional signals from different sources, including the face, the whole body, and the natural scene. Previous research has shown the importance of context provided by the whole body and the scene on the recognition of facial expressions. This study measured physiological responses to face-body-scene combinations. Participants freely viewed emotionally congruent and incongruent face-body and body-scene pairs whilst eye fixations, pupil-size, and electromyography (EMG) responses were recorded. Participants attended more to angry and fearful vs. happy or neutral cues, independent of the source and relatively independent from whether the face body and body scene combinations were emotionally congruent or not. Moreover, angry faces combined with angry bodies and angry bodies viewed in aggressive social scenes elicited greatest pupil dilation. Participants' face expressions matched the valence of the stimuli but when face-body compounds were shown, the observed facial expression influenced EMG responses more than the posture. Together, our results show that the perception of emotional signals from faces, bodies and scenes depends on the natural context, but when threatening cues are presented, these threats attract attention, induce arousal, and evoke congruent facial reactions. PMID:24391567

  16. Emotional signals from faces, bodies and scenes influence observers' face expressions, fixations and pupil-size.

    PubMed

    Kret, Mariska E; Roelofs, Karin; Stekelenburg, Jeroen J; de Gelder, Beatrice

    2013-01-01

    We receive emotional signals from different sources, including the face, the whole body, and the natural scene. Previous research has shown the importance of context provided by the whole body and the scene on the recognition of facial expressions. This study measured physiological responses to face-body-scene combinations. Participants freely viewed emotionally congruent and incongruent face-body and body-scene pairs whilst eye fixations, pupil-size, and electromyography (EMG) responses were recorded. Participants attended more to angry and fearful vs. happy or neutral cues, independent of the source and relatively independent from whether the face body and body scene combinations were emotionally congruent or not. Moreover, angry faces combined with angry bodies and angry bodies viewed in aggressive social scenes elicited greatest pupil dilation. Participants' face expressions matched the valence of the stimuli but when face-body compounds were shown, the observed facial expression influenced EMG responses more than the posture. Together, our results show that the perception of emotional signals from faces, bodies and scenes depends on the natural context, but when threatening cues are presented, these threats attract attention, induce arousal, and evoke congruent facial reactions.

  17. Correlates of Research Effort in Carnivores: Body Size, Range Size and Diet Matter

    PubMed Central

    Brooke, Zoe M.; Bielby, Jon; Nambiar, Kate; Carbone, Chris

    2014-01-01

    Given the budgetary restrictions on scientific research and the increasing need to better inform conservation actions, it is important to identify the patterns and causes of biases in research effort. We combine bibliometric information from a literature review of almost 16,500 peer-reviewed publications on a well-known group of 286 species, the Order Carnivora, with global datasets on species' life history and ecological traits to explore patterns in research effort. Our study explores how species' characteristics influenced the degree to which they were studied (measured as the number of publications). We identified a wide variation in intensity of research effort at both Family and Species levels, with some of the least studied being those which may need protection in future. Our findings hint at the complex role of human perspectives in setting research agendas. We found that better-studied species tended to be large-bodied and have a large geographic range whilst omnivory had a negative relationship with research effort. IUCN threat status did not exhibit a strong relationship with research effort which suggests that the conservation needs of individual species are not major drivers of research interest. This work is the first to use a combination of bibliometric analysis and biological data to quantify and interpret gaps in research knowledge across an entire Order. Our results could be combined with other resources, such as Biodiversity Action Plans, to prioritise and co-ordinate future research effort, whilst our methods can be applied across many scientific disciplines to describe knowledge gaps. PMID:24695422

  18. Correlates of research effort in carnivores: body size, range size and diet matter.

    PubMed

    Brooke, Zoe M; Bielby, Jon; Nambiar, Kate; Carbone, Chris

    2014-01-01

    Given the budgetary restrictions on scientific research and the increasing need to better inform conservation actions, it is important to identify the patterns and causes of biases in research effort. We combine bibliometric information from a literature review of almost 16,500 peer-reviewed publications on a well-known group of 286 species, the Order Carnivora, with global datasets on species' life history and ecological traits to explore patterns in research effort. Our study explores how species' characteristics influenced the degree to which they were studied (measured as the number of publications). We identified a wide variation in intensity of research effort at both Family and Species levels, with some of the least studied being those which may need protection in future. Our findings hint at the complex role of human perspectives in setting research agendas. We found that better-studied species tended to be large-bodied and have a large geographic range whilst omnivory had a negative relationship with research effort. IUCN threat status did not exhibit a strong relationship with research effort which suggests that the conservation needs of individual species are not major drivers of research interest. This work is the first to use a combination of bibliometric analysis and biological data to quantify and interpret gaps in research knowledge across an entire Order. Our results could be combined with other resources, such as Biodiversity Action Plans, to prioritise and co-ordinate future research effort, whilst our methods can be applied across many scientific disciplines to describe knowledge gaps.

  19. Body shape and size in 6-year old children: assessment by three-dimensional photonic scanning

    PubMed Central

    Santos, L P; Ong, K K; Day, F; Wells, J C K; Matijasevich, A; Santos, I S; Victora, C G; Barros, A J D

    2016-01-01

    Background: Body shape and size are typically described using measures such as body mass index (BMI) and waist circumference, which predict disease risks in adults. However, this approach may underestimate the true variability in childhood body shape and size. Objective: To use a comprehensive three-dimensional photonic scan approach to describe variation in childhood body shape and size. Subjects/Methods: At age 6 years, 3350 children from the population-based 2004 Pelotas birth cohort study were assessed by three-dimensional photonic scanner, traditional anthropometry and dual X-ray absorptiometry. Principal component analysis (PCA) was performed on height and 24 photonic scan variables (circumferences, lengths/widths, volumes and surface areas). Results: PCA identified four independent components of children's body shape and size, which we termed: Corpulence, Central:peripheral ratio, Height and arm lengths, and Shoulder diameter. Corpulence showed strong correlations with traditional anthropometric and body composition measures (r>0.90 with weight, BMI, waist circumference and fat mass; r>0.70 with height, lean mass and bone mass); in contrast, the other three components showed weak or moderate correlations with those measures (all r<0.45). There was no sex difference in Corpulence, but boys had higher Central:peripheral ratio, Height and arm lengths and Shoulder diameter values than girls. Furthermore, children with low birth weight had lower Corpulence and Height and arm lengths but higher Central:peripheral ratio and Shoulder diameter than other children. Children from high socio-economic position (SEP) families had higher Corpulence and Height and arm lengths than other children. Finally, white children had higher Corpulence and Central:peripheral ratio than mixed or black children. Conclusions: Comprehensive assessment by three-dimensional photonic scanning identified components of childhood body shape and size not captured by traditional anthropometry or

  20. Rates and modes of body size evolution in early carnivores and herbivores: a case study from Captorhinidae

    PubMed Central

    2016-01-01

    Body size is an extremely important characteristic, impacting on a variety of ecological and life-history traits. It is therefore important to understand the factors which may affect its evolution, and diet has attracted much interest in this context. A recent study which examined the evolution of the earliest terrestrial herbivores in the Late Carboniferous and Early Permian concluded that in the four herbivorous clades examined there was a trend towards increased body size, and that this increase was more substantial than that observed in closely related carnivorous clades. However, this hypothesis was not based on quantitative examination, and phylogenetic comparative methods provide a more robust means of testing such hypotheses. Here, the evolution of body size within different dietary regimes is examined in Captorhinidae, the most diverse and longest lived of these earliest high fibre herbivores. Evolutionary models were fit to their phylogeny to test for variation in rate and mode of evolution between the carnivorous and herbivorous members of this clade, and an analysis of rate variation throughout the tree was carried out. Estimates of ancestral body sizes were calculated in order to compare the rates and direction of evolution of lineages with different dietary regimes. Support for the idea that the high fibre herbivores within captorhinids are being drawn to a higher adaptive peak in body size than the carnivorous members of this clade is weak. A shift in rates of body size evolution is identified, but this does not coincide with the evolution of high-fibre herbivory, instead occurring earlier in time and at a more basal node. Herbivorous lineages which show an increase in size are not found to evolve at a faster rate than those which show a decrease; in fact, it is those which experience a size decrease which evolve at higher rates. It is possible the shift in rates of evolution is related to the improved food processing ability of the more derived

  1. Microhabitat and body size effects on heat tolerance: implications for responses to climate change (army ants: Formicidae, Ecitoninae).

    PubMed

    Baudier, Kaitlin M; Mudd, Abigail E; Erickson, Shayna C; O'Donnell, Sean

    2015-09-01

    1. Models that predict organismal and population responses to climate change may be improved by considering ecological factors that affect species thermal tolerance. Species differences in microhabitat use can expose animals to diverse thermal selective environments at a given site and may cause sympatric species to evolve different thermal tolerances. 2. We tested the hypothesis that species differences in body size and microhabitat use (above- vs. below-ground activity) would correspond to differences in thermal tolerance (maximum critical temperatures: CTmax ). Thermal buffering effects of soil can reduce exposure to extreme high temperatures for below-ground active species. We predicted larger-bodied individuals and species would have higher CTmax and that species mean CTmax would covary positively with degree of above-ground activity. We used Neotropical army ants (Formicidae: Ecitoninae) as models. Army ants vary in microhabitat use from largely subterranean to largely above-ground active species and are highly size polymorphic. 3. We collected data on above- and below-ground temperatures in habitats used by army ants to test for microhabitat temperature differences, and we conducted CTmax assays for army ant species with varying degrees of surface activity and with different body sizes within and between species. We then tested whether microhabitat use was associated with species differences in CTmax and whether microhabitat was a better predictor of CTmax than body size for species that overlapped in size. 4. Microhabitat use was a highly significant predictor of species' upper thermal tolerance limits, both for raw data and after accounting for the effects of phylogeny. Below-ground species were more thermally sensitive, with lower maximum critical temperatures (CTmax ). The smallest workers within each species were the least heat tolerant, but the magnitude of CTmax change with body size was greater in below-ground species. Species-typical microhabitat

  2. Geohistorical records indicate no impact of the Deepwater Horizon oil spill on oyster body size

    PubMed Central

    Durham, Stephen R.

    2016-01-01

    Documentation of the near- and long-term effects of the Deepwater Horizon (DWH) oil spill, one of the largest environmental disasters in US history, is still ongoing. We used a novel before-after-control-impact analysis to test the hypothesis that average body size of intertidal populations of the eastern oyster (Crassostrea virginica) inhabiting impacted areas in Louisiana decreased due to increased stress/mortality related to the oil spill. Time-averaged death assemblages of oysters were used to establish a pre-spill baseline of body-size structure for four impacted and four control locations along a 350 km stretch of Louisiana's coastline. Post-spill body sizes were then measured from live oysters at each site in order to evaluate the differences in body size between oiled (i.e. impact) and unoiled (i.e. control) locations before and after the spill. Our results indicate that average body size of oysters remained relatively unchanged after the oil spill. There were also no temporal patterns in temperature, salinity or disease prevalence that could have explained our results. Together, these findings suggest that oysters either recovered rapidly following the immediate impact of the DWH oil spill, or that its impact was not severe enough to influence short-term population dynamics of the oyster beds. PMID:28018663

  3. The Role of Body Size in Mate Selection among African American Young Adults

    PubMed Central

    Simons, Leslie G.; Simons, Ronald L.

    2016-01-01

    A profusion of studies have demonstrated that body size is a major factor in mate selection for both men and women. The particular role played by weight, however, has been subject to some debate, particularly with respect to the types of body sizes deemed most attractive, and scholars have questioned the degree to which body size preferences are constant across groups. In this paper, we drew from two perspectives on this issue, Sexual Strategies Theory and what we termed the cultural variability perspective, and used survey data to examine how body size was associated with both casual dating and serious romantic relationships. We used a United States sample of 386 African American adolescents and young adults between ages 16 and 21, living in the Midwest and Southeast, and who were enrolled in either high school or college. Results showed that overweight women were more likely to report casually dating than women in the thinnest weight category. Body size was not related to dating status among men. Among women, the results suggest stronger support for the cultural variability argument than for Sexual Strategies Theory. Potential explanations for these findings are discussed. PMID:26973377

  4. Longevity, life history, and relative body wall size in sea urchins

    SciTech Connect

    Ebert, T.A.

    1982-12-01

    Annual survival rates in 38 populations of 17 sea urchin species in the Indo-West Pacific were related to relative size of the body wall and exposure to the surf. Populations were studied at Hawaii, Enewetak Atok, Queensland, New South Wales and Western Australia, Sri Lanka, Seychelles, Kenya, Zanzibar, and Isaerl (Eilat). Live animals were dissected to determine the size of body components. Parameters of the Richards growth function were determined from animals tagged with tetracycline. Tagged animals were collected after they had been in the field for 1 yr. Growth parameters were used with parameters from size-frequency distributions to estimate Z, the mortality coefficient. Stepwise multiple regression was used to examine the relationship between annual survival probability (p) and two indepencent variables, ..cap alpha.. and E, where E is a subjective measure of exposure to surf (1 = most exposed). Survivorship increases with increased relative size of the body wall and with increased protection from the surf. The positive relationship between survival probability and relative body wall size supports the hypothesis that survival is related to allocation of resources to maintenance. The significane of longevity in urchins probably is that it is related to the predictability of survival of prereproductive individuals. The greater the unpredictability, the longer life must be. Long life requires a greater investment in maintenance mechanisms and hence, among other adaptations, a more massive body wall.

  5. Geohistorical records indicate no impact of the Deepwater Horizon oil spill on oyster body size.

    PubMed

    Dietl, Gregory P; Durham, Stephen R

    2016-11-01

    Documentation of the near- and long-term effects of the Deepwater Horizon (DWH) oil spill, one of the largest environmental disasters in US history, is still ongoing. We used a novel before-after-control-impact analysis to test the hypothesis that average body size of intertidal populations of the eastern oyster (Crassostrea virginica) inhabiting impacted areas in Louisiana decreased due to increased stress/mortality related to the oil spill. Time-averaged death assemblages of oysters were used to establish a pre-spill baseline of body-size structure for four impacted and four control locations along a 350 km stretch of Louisiana's coastline. Post-spill body sizes were then measured from live oysters at each site in order to evaluate the differences in body size between oiled (i.e. impact) and unoiled (i.e. control) locations before and after the spill. Our results indicate that average body size of oysters remained relatively unchanged after the oil spill. There were also no temporal patterns in temperature, salinity or disease prevalence that could have explained our results. Together, these findings suggest that oysters either recovered rapidly following the immediate impact of the DWH oil spill, or that its impact was not severe enough to influence short-term population dynamics of the oyster beds.

  6. Evolving concepts on adjusting human resting energy expenditure measurements for body size.

    PubMed

    Heymsfield, S B; Thomas, D; Bosy-Westphal, A; Shen, W; Peterson, C M; Müller, M J

    2012-11-01

    Establishing if an adult's resting energy expenditure (REE) is high or low for their body size is a pervasive question in nutrition research. Early workers applied body mass and height as size measures and formulated the Surface Law and Kleiber's Law, although each has limitations when adjusting REE. Body composition methods introduced during the mid-20th century provided a new opportunity to identify metabolically homogeneous 'active' compartments. These compartments all show improved correlations with REE estimates over body mass-height approaches, but collectively share a common limitation: REE-body composition ratios are not 'constant' but vary across men and women and with race, age and body size. The now-accepted alternative to ratio-based norms is to adjust for predictors by applying regression models to calculate 'residuals' that establish if an REE is relatively high or low. The distinguishing feature of statistical REE-body composition models is a 'non-zero' intercept of unknown origin. The recent introduction of imaging methods has allowed development of physiological tissue-organ-based REE prediction models. Herein, we apply these imaging methods to provide a mechanistic explanation, supported by experimental data, for the non-zero intercept phenomenon and, in that context, propose future research directions for establishing between-subject differences in relative energy metabolism.

  7. Differences in body size and egg loads of Rhagoletis indifferens (Diptera: Tephritidae) from introduced and native cherries.

    PubMed

    Yee, Wee L; Goughnour, Robert B; Feder, Jeffrey L

    2011-12-01

    The western cherry fruit fly, Rhagoletis indifferens Curran, infests introduced, domesticated sweet [Prunus avium (L.) L.], and tart cherries (Prunus cerasus L.) as well as native bitter cherry, Prunus emarginata (Douglas) Eaton. Bitter cherries are smaller than sweet and tart cherries and this could affect various life history traits of flies. The objectives of the current study were to determine 1) if body size and egg loads of flies infesting sweet, tart, and bitter cherries differ from one another; and 2) if any observed body size differences are genetically based or caused by the host fruit environment. Pupae and adults of both sexes reared from larval-infested sweet and tart cherries collected in Washington and Montana were larger than those reared from bitter cherries. In addition, flies of both sexes caught on traps in sweet and tart cherry trees were larger than those caught in bitter cherry trees and females trapped from sweet and tart cherry trees had 54.0-98.8% more eggs. The progeny of flies from naturally-infested sweet and bitter cherries reared for one generation in the laboratory on sweet cherry did not differ in size. The same also was true for progeny of sweet and bitter cherry flies reared in the field on bitter cherry. The results suggest that the larger body sizes of flies from sweet and tart cherries than bitter cherries in the field are caused by host fruit and not genetic factors.

  8. Does large body size in males evolve to facilitate forcible insemination? A study on garter snakes.

    PubMed

    Shine, Richard; Mason, Robert T

    2005-11-01

    A trend for larger males to obtain a disproportionately high number of matings, as occurs in many animal populations, typically is attributed either to female choice or success in male-male rivalry; an alternative mechanism, that larger males are better able to coercively inseminate females, has received much less attention. For example, previous studies on garter snakes (Thamnophis sirtalis parietalis) at communal dens in Manitoba have shown that the mating benefit to larger body size in males is due to size-dependent advantages in male-male rivalry. However, this previous work ignored the possibility that larger males may obtain more matings because of male-female interactions. In staged trials within outdoor arenas, larger body size enhanced male mating success regardless of whether a rival male was present. The mechanism involved was coercion rather than female choice, because mating occurred most often (and soonest) in females that were least able to resist courtship-induced hypoxic stress. Males do physically displace rivals from optimal positions in the mating ball, and larger males are better able to resist such displacement. Nonetheless, larger body size enhances male mating success even in the absence of such male-male interactions. Thus, even in mating systems where males compete physically and where larger body size confers a significant advantage in male-male competition, the actual selective force for larger body size in males may relate to forcible insemination of unreceptive females. Experimental studies are needed to determine whether the same situation occurs in other organisms in which body-size advantages have been attributed to male-male rather than male-female interactions.

  9. The 'island rule' in birds: medium body size and its ecological explanation.

    PubMed

    Clegg, Sonya M; Owens, Ian P F

    2002-07-07

    Do birds show a different pattern of insular evolution from mammals? Mammals follow the 'island rule', with large-bodied species getting smaller on islands and small-bodied species getting bigger. By contrast, the traditional view on birds is that they follow no general island rule for body size, but that there is an insular trend for large bills. Insular shifts in feeding ecology are, therefore, widely assumed to be the primary cause of divergence in island birds. We use a comparative approach to test these ideas. Contrary to the traditional view, we find no evidence for increased bill size in insular populations. Instead, changes in both bill size and body size obey the 'island rule'. The differences between our results and the traditional view arise because previous analyses were based largely on passerines. We also investigate some ecological factors that are thought to influence island evolution. As predicted by the traditional view, shifts in bill size are associated with feeding ecology. By contrast, shifts in body size are associated with the potential for intraspecific competition and thermal ecology. All these results remain qualitatively unchanged when we use different methods to score the ecological factors and restrict our analyses to taxa showing pronounced morphological divergence. Because of strong covariation between ecological factors, however, we cannot estimate the relative importance of each ecological factor. Overall, our results show that the island rule is valid for both body size and bill length in birds and that, in addition to feeding ecology, insular shifts in the level of intraspecific competition and the abiotic environment also have a role.

  10. Despite Buffers, Experimental Forest Clearcuts Impact Amphibian Body Size and Biomass.

    PubMed

    Veysey Powell, Jessica S; Babbitt, Kimberly J

    2015-01-01

    Forest buffers are a primary tool used to protect wetland-dependent wildlife. Though implemented widely, buffer efficacy is untested for most amphibian species. Consequently, it remains unclear whether buffers are sufficient for maintaining amphibian populations and if so, how wide buffers should be. We present evidence from a six-year, landscape-scale experiment testing the impacts of clearcutting, buffer width, and hydroperiod on body size and condition and biomass of breeding adults for two amphibian species at 11 vernal pools in the northeastern United States. We randomly assigned treatments (i.e., reference, 100m buffer, 30m buffer) across pools, clearcut to create buffers, and captured all spotted salamanders and wood frogs. Clearcuts strongly and negatively impacted size, condition, and biomass, but wider buffers mitigated effect magnitude and duration. Among recaptured individuals, for example, 30m-treatment salamanders were predicted to be about 9.5 mm shorter than, while 100m-treatment salamanders did not differ in length from, reference-treatment salamanders. Similarly, among recaptured frogs, mean length in the 30m treatment was predicted to decrease by about 1 mm/year, while in the 100m and reference treatments, length was time-invariant. Some, but not all, metrics recovered with time. For example, female new-captured and recaptured salamanders were predicted, respectively and on average, to weigh 4.5 and 7 g less in the 30m versus reference treatment right after the cut. While recaptured-female mass was predicted to recover by 9.5 years post-cut, new-captured-female mass did not recover. Hydroperiod was an important mediator: in the 100m treatment, cutting predominately affected pools that were stressed hydrologically. Overall, salamanders and female frogs were impacted more than male frogs. Our results highlight the importance of individualized metrics like body size, which can reveal sublethal effects and illuminate mechanisms by which habitat

  11. Despite Buffers, Experimental Forest Clearcuts Impact Amphibian Body Size and Biomass

    PubMed Central

    Veysey Powell, Jessica S.; Babbitt, Kimberly J.

    2015-01-01

    Forest buffers are a primary tool used to protect wetland-dependent wildlife. Though implemented widely, buffer efficacy is untested for most amphibian species. Consequently, it remains unclear whether buffers are sufficient for maintaining amphibian populations and if so, how wide buffers should be. We present evidence from a six-year, landscape-scale experiment testing the impacts of clearcutting, buffer width, and hydroperiod on body size and condition and biomass of breeding adults for two amphibian species at 11 vernal pools in the northeastern United States. We randomly assigned treatments (i.e., reference, 100m buffer, 30m buffer) across pools, clearcut to create buffers, and captured all spotted salamanders and wood frogs. Clearcuts strongly and negatively impacted size, condition, and biomass, but wider buffers mitigated effect magnitude and duration. Among recaptured individuals, for example, 30m-treatment salamanders were predicted to be about 9.5 mm shorter than, while 100m-treatment salamanders did not differ in length from, reference-treatment salamanders. Similarly, among recaptured frogs, mean length in the 30m treatment was predicted to decrease by about 1 mm/year, while in the 100m and reference treatments, length was time-invariant. Some, but not all, metrics recovered with time. For example, female new-captured and recaptured salamanders were predicted, respectively and on average, to weigh 4.5 and 7 g less in the 30m versus reference treatment right after the cut. While recaptured-female mass was predicted to recover by 9.5 years post-cut, new-captured-female mass did not recover. Hydroperiod was an important mediator: in the 100m treatment, cutting predominately affected pools that were stressed hydrologically. Overall, salamanders and female frogs were impacted more than male frogs. Our results highlight the importance of individualized metrics like body size, which can reveal sublethal effects and illuminate mechanisms by which habitat

  12. Body Size Evolution in Conodonts from the Cambrian through the Triassic

    NASA Astrophysics Data System (ADS)

    Schaal, E. K.; Morgan, D. J.; Payne, J.

    2013-12-01

    The size of an organism exercises tremendous control over its physiology, life history, and ecology, yet the factors that influence body size evolution remain poorly understood. One major limitation is the lack of appropriate datasets spanning long intervals of evolutionary time. Here, we document size trends in conodonts (tooth-like microfossils from marine chordates) because they evolved rapidly and are known to change size during intervals of environmental change. By measuring photographs from the Catalogue of Conodonts (Ziegler 1982), we compiled a database of conodont P1 element measurements for 575 species and subspecies from the Cambrian through Triassic periods. Because tooth size correlates with body size in conodont animals and their extant relatives, conodont element length can serve as a proxy for the size of the conodont animal. We find that mean and maximum size across species increased during the early Paleozoic, peaked during the Devonian-Mississippian, and then generally decreased until conodonts went extinct at the end of the Triassic. We used regression analyses to compare conodont mean size trends to potential environmental predictors, such as changing atmospheric pO2, atmospheric pCO2, and sea level. Conodont size exhibited poor correlation with these environmental factors, suggesting that conodont evolution may have been more strongly influenced by other environmental covariates or ecological variables such as predation and competition.

  13. Volitional exaggeration of body size through fundamental and formant frequency modulation in humans

    PubMed Central

    Pisanski, Katarzyna; Mora, Emanuel C.; Pisanski, Annette; Reby, David; Sorokowski, Piotr; Frackowiak, Tomasz; Feinberg, David R.

    2016-01-01

    Several mammalian species scale their voice fundamental frequency (F0) and formant frequencies in competitive and mating contexts, reducing vocal tract and laryngeal allometry thereby exaggerating apparent body size. Although humans’ rare capacity to volitionally modulate these same frequencies is thought to subserve articulated speech, the potential function of voice frequency modulation in human nonverbal communication remains largely unexplored. Here, the voices of 167 men and women from Canada, Cuba, and Poland were recorded in a baseline condition and while volitionally imitating a physically small and large body size. Modulation of F0, formant spacing (∆F), and apparent vocal tract length (VTL) were measured using Praat. Our results indicate that men and women spontaneously and systemically increased VTL and decreased F0 to imitate a large body size, and reduced VTL and increased F0 to imitate small size. These voice modulations did not differ substantially across cultures, indicating potentially universal sound-size correspondences or anatomical and biomechanical constraints on voice modulation. In each culture, men generally modulated their voices (particularly formants) more than did women. This latter finding could help to explain sexual dimorphism in F0 and formants that is currently unaccounted for by sexual dimorphism in human vocal anatomy and body size. PMID:27687571

  14. Population Variation Reveals Independent Selection toward Small Body Size in Chinese Debao Pony

    PubMed Central

    Kader, Adiljan; Li, Yan; Dong, Kunzhe; Irwin, David M.; Zhao, Qianjun; He, Xiaohong; Liu, Jianfeng; Pu, Yabin; Gorkhali, Neena Amatya; Liu, Xuexue; Jiang, Lin; Li, Xiangchen; Guan, Weijun; Zhang, Yaping; Wu, Dong-Dong; Ma, Yuehui

    2016-01-01

    Body size, one of the most important quantitative traits under evolutionary scrutiny, varies considerably among species and among populations within species. Revealing the genetic basis underlying this variation is very important, particularly in humans where there is a close relationship with diseases and in domestic animals as the selective patterns are associated with improvements in production traits. The Debao pony is a horse breed with small body size that is unique to China; however, it is unknown whether the size-related candidate genes identified in Western breeds also account for the small body size of the Debao pony. Here, we compared individual horses from the Debao population with other two Chinese horse populations using single nucleotide polymorphisms (SNPs) identified with the Equine SNP 65 Bead Chip. The previously reported size-related candidate gene HMGA2 showed a significant signature for selection, consistent with its role observed in human populations. More interestingly, we found a candidate gene TBX3, which had not been observed in previous studies on horse body size that displayed the highest differentiation and most significant association, and thus likely is the dominating factor for the small stature of the Debao pony. Further comparison between the Debao pony and other breeds of horses from around the world demonstrated that TBX3 was selected independently in the Debao pony, suggesting that there were multiple origins of small stature in the horse. PMID:26637467

  15. Exceptional body sizes but typical trophic structure in a Pleistocene food web.

    PubMed

    Segura, Angel M; Fariña, Richard A; Arim, Matías

    2016-05-01

    In this study, we focused on the exceptionally large mammals inhabiting the Americas during the Quaternary period and the paramount role of body size in species ecology. We evaluated two main features of Pleistocene food webs: the relationship between body size and (i) trophic position and (ii) vulnerability to predation. Despite the large range of species sizes, we found a hump-shaped relationship between trophic position and body size. We also found a negative trend in species vulnerability similar to that observed in modern faunas. The largest species lived near the boundary of energetic constraints, such that any shift in resource availability could drive these species to extinction. Our results reinforce several features of megafauna ecology: (i) the negative relationship between trophic position and body size implies that large-sized species were particularly vulnerable to changes in energetic support; (ii) living close to energetic imbalance could favour the incorporation of additional energy sources, for example, a transition from a herbivorous to a scavenging diet in the largest species (e.g. Megatherium) and (iii) the interactions and structure of Quaternary megafauna communities were shaped by similar forces to those shaping modern fauna communities.

  16. Investigating yellow dung fly body size evolution in the field: Response to climate change?

    PubMed

    Blanckenhorn, Wolf U

    2015-08-01

    Uncovering genetic responses to selection in wild populations typically requires tracking individuals over generations and use of animal models. Our group monitored the body size of one Swiss Yellow Dung Fly (Scathophaga stercoraria; Diptera: Scathophagidae) field population over 15 years, including intermittent common-garden rearing in the laboratory to assess body size with minimized environmental and maximized genetic variation. Contrary to expectations based on repeated heritability and phenotypic selection assessments over the years (reported elsewhere), field body sizes declined by >10% and common-garden laboratory sizes by >5% from 1993 to 2009. Our results confirm the temperature-size rule (smaller when warmer) and, albeit entirely correlational, could be mediated by climate change, as over this period mean temperature at the site increased by 0.5°C, although alternative systematic environmental changes cannot be entirely excluded. Monitoring genetic responses to selection in wild invertebrate populations is thus possible, though indirect, and wild populations may evolve in directions not consistent with strongly positive directional selection favoring large body size.

  17. Body size and mortality rates in coral reef fishes: a three-phase relationship.

    PubMed

    Goatley, Christopher Harry Robert; Bellwood, David Roy

    2016-10-26

    Body size is closely linked to mortality rates in many animals, although the overarching patterns in this relationship have rarely been considered for multiple species. A meta-analysis of published size-specific mortality rates for coral reef fishes revealed an exponential decline in mortality rate with increasing body size, however, within this broad relationship there are three distinct phases. Phase one is characterized by naive fishes recruiting to reefs, which suffer extremely high mortality rates. In this well-studied phase, fishes must learn quickly to survive the many predation risks. After just a few days, the surviving fishes enter phase two, in which small increases in body size result in pronounced increases in lifespan (estimated 11 d mm(-1)). Remarkably, approximately 50% of reef fish individuals remain in phase two throughout their lives. Once fishes reach a size threshold of about 43 mm total length (TL) they enter phase three, where mortality rates are relatively low and the pressure to grow is presumably, significantly reduced. These phases provide a clearer understanding of the impact of body size on mortality rates in coral reef fishes and begin to reveal critical insights into the energetic and trophic dynamics of coral reefs.

  18. Variations in otolith patterns, sizes and body morphometrics of jack mackerel Trachurus japonicus juveniles.

    PubMed

    Kanaji, Y; Kishida, M; Watanabe, Y; Kawamura, T; Xie, S; Yamashita, Y; Sassa, C; Tsukamoto, Y

    2010-10-01

    Variations in otolith patterns, sizes and body morphometrics of jack mackerel Trachurus japonicus juveniles were investigated. Under transmitted light, translucent (W(t)) and opaque otoliths (W(o)) were detected in juveniles collected from Wakasa Bay between July 2005 and April 2006, whereas only opaque otoliths (G(o)) were detected in Goto-nada Sea individuals between May and June 2006. Three groups of juveniles were distinguished based on differences in hatch season, otolith size and growth history, and body morphometrics. As T. japonicus has different spawning seasons according to spawning grounds, each group was estimated to hatch in different waters. Juveniles with W(t) otoliths were considered to have stayed in coastal habitat longer, as the hatch area was estimated to be near Wakasa Bay. Juveniles with W(o) and G(o) otoliths appear to recruit to coastal waters at larger size, since their hatch areas were estimated to be far from each collection area. Larger otoliths of W(t) were attributed to otolith accretion after the second growth flexion, which was observed only for W(t) . Standard length of W(t) fish at the second otolith growth flexion was estimated to correspond to recruitment size to coastal rocky reefs in Wakasa Bay. Body morphometrics were correlated with otolith size after removing body size effect, suggesting that morphological variations of T. japonicus juveniles were also associated with the timing of recruitment to coastal habitat.

  19. Comparison of cell body size and oxidative enzyme activity in motoneurons between the cervical and lumbar segments in the rat spinal cord after spaceflight and recovery.

    PubMed

    Ishihara, A; Yamashiro, J; Matsumoto, A; Higashibata, A; Ishioka, N; Shimazu, T; Ohira, Y

    2006-03-01

    The cell body sizes and succinate dehydrogenase (SDH) activities of motoneurons in the dorsolateral region of the ventral horn at the cervical and lumbar segments in the rat spinal cord were determined following 9 days of spaceflight with or without 10 days of recovery on Earth. The motoneurons were divided into three types based on their cell body sizes; small-, medium-, and large-sized motoneurons. In control rats, there was no difference in the cell body size or SDH activity of small- and large-sized motoneurons between the cervical and lumbar segments. The SDH activity of medium-sized motoneurons in control rats was higher in the lumbar segment than in the cervical segment, while the cell body sizes of medium-sized motoneurons were identical. The SDH activity of medium-sized motoneurons in the lumbar segment decreased to a level similar to that in the cervical segment of control rats following spaceflight. In addition, the decreased SDH activity of medium-sized motoneurons persisted for at least 10 days of recovery on Earth. It is concluded that spaceflight selectively affects the SDH activity of medium-sized motoneurons in the lumbar segment of the spinal cord, which presumably innervate skeletal muscles having an antigravity function.

  20. Body size in early life and risk of lymphoid malignancies and histological subtypes in adulthood.

    PubMed

    Yang, TienYu Owen; Cairns, Benjamin J; Kroll, Mary E; Reeves, Gillian K; Green, Jane; Beral, Valerie

    2016-07-01

    Risk of adult lymphoid malignancy is associated with recent adiposity. Some have reported apparent associations with adiposity in childhood or early adulthood, but whether these associations are independent of recent adiposity is unknown. Birth weight, body size at age 10 years, clothes size at age 20 years, and recent body mass index (BMI) were recorded in 745,273 UK women, mean age 60.1 (SD 4.9) at baseline, without prior cancer. They were followed for 11 years, during which time 5,765 lymphoid malignancies occurred. Using Cox regression, a higher risk of lymphoid malignancy was strongly associated with higher recent BMI (RR=1.33, 95%CI 1.17-1.51, for BMI 35+ vs <22.5 kg/m(2)), and this association remained essentially unchanged after adjustment for birth weight and body size at 10. Higher lymphoid malignancy risk was also associated with large size at birth, at age 10, and at age 20 years, but after adjustment for recent BMI, the significance of the associations with large size at birth and at age 10 years was sufficiently reduced that residual confounding by adult BMI could not be excluded; a weak association with large size at 20 years remained (adjusted RR =1.17, 95%CI 1.10-1.24 for large size at age 20 vs. medium or small size). We found no strong evidence of histological specificity in any of these associations. In conclusion, our findings suggest a possible role of adiposity throughout adulthood in the risk of lymphoid malignancy, but the independent contribution of body size at birth and during childhood appears to be small.

  1. Warming-induced reductions in body size are greater in aquatic than terrestrial species.

    PubMed

    Forster, Jack; Hirst, Andrew G; Atkinson, David

    2012-11-20

    Most ectothermic organisms mature at smaller body sizes when reared in warmer conditions. This phenotypically plastic response, known as the "temperature-size rule" (TSR), is one of the most taxonomically widespread patterns in biology. However, the TSR remains a longstanding life-history puzzle for which no dominant driver has been found. We propose that oxygen supply plays a central role in explaining the magnitude of ectothermic temperature-size responses. Given the much lower oxygen availability and greater effort required to increase uptake in water vs. air, we predict that the TSR in aquatic organisms, especially larger species with lower surface area-body mass ratios, will be stronger than in terrestrial organisms. We performed a meta-analysis of 1,890 body mass responses to temperature in controlled experiments on 169 terrestrial, freshwater, and marine species. This reveals that the strength of the temperature-size response is greater in aquatic than terrestrial species. In animal species of ∼100 mg dry mass, the temperature-size response of aquatic organisms is 10 times greater than in terrestrial organisms (-5.0% °C(-1) vs. -0.5% °C(-1)). Moreover, although the size response of small (<0.1 mg dry mass) aquatic and terrestrial species is similar, increases in species size cause the response to become increasingly negative in aquatic species, as predicted, but on average less negative in terrestrial species. These results support oxygen as a major driver of temperature-size responses in aquatic organisms. Further, the environment-dependent differences parallel latitudinal body size clines, and will influence predicted impacts of climate warming on food production, community structure, and food-web dynamics.

  2. Body size in early life and risk of lymphoid malignancies and histological subtypes in adulthood

    PubMed Central

    Cairns, Benjamin J.; Kroll, Mary E.; Reeves, Gillian K.; Green, Jane; Beral, Valerie

    2016-01-01

    Risk of adult lymphoid malignancy is associated with recent adiposity. Some have reported apparent associations with adiposity in childhood or early adulthood, but whether these associations are independent of recent adiposity is unknown. Birth weight, body size at age 10 years, clothes size at age 20 years, and recent body mass index (BMI) were recorded in 745,273 UK women, mean age 60.1 (SD 4.9) at baseline, without prior cancer. They were followed for 11 years, during which time 5,765 lymphoid malignancies occurred. Using Cox regression, a higher risk of lymphoid malignancy was strongly associated with higher recent BMI (RR=1.33, 95%CI 1.17‐1.51, for BMI 35+ vs <22.5 kg/m2), and this association remained essentially unchanged after adjustment for birth weight and body size at 10. Higher lymphoid malignancy risk was also associated with large size at birth, at age 10, and at age 20 years, but after adjustment for recent BMI, the significance of the associations with large size at birth and at age 10 years was sufficiently reduced that residual confounding by adult BMI could not be excluded; a weak association with large size at 20 years remained (adjusted RR =1.17, 95%CI 1.10–1.24 for large size at age 20 vs. medium or small size). We found no strong evidence of histological specificity in any of these associations. In conclusion, our findings suggest a possible role of adiposity throughout adulthood in the risk of lymphoid malignancy, but the independent contribution of body size at birth and during childhood appears to be small. PMID:26888490

  3. Latitudinal variation in the shape of the species body size distribution: an analysis using freshwater fishes.

    PubMed

    Knouft, Jason H

    2004-05-01

    Many taxonomic and ecological assemblages of species exhibit a right-skewed body size-frequency distribution when characterized at a regional scale. Although this distribution has been frequently described, factors influencing geographic variation in the distribution are not well understood, nor are mechanisms responsible for distribution shape. In this study, variation in the species body size-frequency distributions of 344 regional communities of North American freshwater fishes is examined in relation to latitude, species richness, and taxonomic composition. Although the distribution of all species of North American fishes is right-skewed, a negative correlation exists between latitude and regional community size distribution skewness, with size distributions becoming left-skewed at high latitudes. This relationship is not an artifact of the confounding relationship between latitude and species richness in North American fishes. The negative correlation between latitude and regional community size distribution skewness is partially due to the geographic distribution of families of fishes and apparently enhanced by a nonrandom geographic distribution of species within families. These results are discussed in the context of previous explanations of factors responsible for the generation of species size-frequency distributions related to the fractal nature of the environment, energetics, and evolutionary patterns of body size in North American fishes.

  4. Body size distributions signal a regime shift in a lake ecosystem

    USGS Publications Warehouse

    Spanbauer, Trisha; Allen, Craig R.; Angeler, David G.; Eason, Tarsha; Fritz, Sherilyn C.; Garmestani, Ahjond S.; Nash, Kirsty L.; Stone, Jeffery R.; Stow, Craig A.; Sundstrom, Shana M.

    2016-01-01

    Communities of organisms, from mammals to microorganisms, have discontinuous distributions of body size. This pattern of size structuring is a conservative trait of community organization and is a product of processes that occur at multiple spatial and temporal scales. In this study, we assessed whether body size patterns serve as an indicator of a threshold between alternative regimes. Over the past 7000 years, the biological communities of Foy Lake (Montana, USA) have undergone a major regime shift owing to climate change. We used a palaeoecological record of diatom communities to estimate diatom sizes, and then analysed the discontinuous distribution of organism sizes over time. We used Bayesian classification and regression tree models to determine that all time intervals exhibited aggregations of sizes separated by gaps in the distribution and found a significant change in diatom body size distributions approximately 150 years before the identified ecosystem regime shift. We suggest that discontinuity analysis is a useful addition to the suite of tools for the detection of early warning signals of regime shifts.

  5. Body size distributions signal a regime shift in a lake ecosystem.

    PubMed

    Spanbauer, Trisha L; Allen, Craig R; Angeler, David G; Eason, Tarsha; Fritz, Sherilyn C; Garmestani, Ahjond S; Nash, Kirsty L; Stone, Jeffery R; Stow, Craig A; Sundstrom, Shana M

    2016-06-29

    Communities of organisms, from mammals to microorganisms, have discontinuous distributions of body size. This pattern of size structuring is a conservative trait of community organization and is a product of processes that occur at multiple spatial and temporal scales. In this study, we assessed whether body size patterns serve as an indicator of a threshold between alternative regimes. Over the past 7000 years, the biological communities of Foy Lake (Montana, USA) have undergone a major regime shift owing to climate change. We used a palaeoecological record of diatom communities to estimate diatom sizes, and then analysed the discontinuous distribution of organism sizes over time. We used Bayesian classification and regression tree models to determine that all time intervals exhibited aggregations of sizes separated by gaps in the distribution and found a significant change in diatom body size distributions approximately 150 years before the identified ecosystem regime shift. We suggest that discontinuity analysis is a useful addition to the suite of tools for the detection of early warning signals of regime shifts.

  6. Discoidin domain receptor 2 (DDR2) regulates body size and fat metabolism in mice.

    PubMed

    Kawai, Ikuma; Matsumura, Hirokazu; Fujii, Wataru; Naito, Kunihiko; Kusakabe, Ken; Kiso, Yasuo; Kano, Kiyoshi

    2014-02-01

    Discoidin domain receptor 2 (DDR2) is a receptor tyrosine kinase that is activated by fibrillar collagens, which act as its endogenous ligand. DDR2 regulates cell proliferation, cell adhesion, migration, extracellular matrix remodeling and reproductive functions. Both DDR2 null allele mice and mice with a recessive, loss-of-function allele for Ddr2 exhibit dwarfing and a reduction in body weight. However, the detailed mechanisms by which DDR2 exerts its positive systemic regulation of whole body size, local skeletal size and fat tissue volume remain to be clarified. To investigate the systemic role of DDR2 in body size regulation, we produced transgenic mice in which the DDR2 protein is overexpressed, then screened the transgenic mice for abnormalities using systematic mouse abnormality screening. The modified-SHIPRA screen revealed that only the parameter of body size was significantly different among the genotypes. We also discovered that the body length was significantly increased, while the body weight was significantly decreased in transgenic mice compared to their littermate controls. We also found that the epididymal fat pads were significantly decreased in transgenic mice compared to normal littermate mice, which may have been the cause of the leptin decrement in the transgenic mice. The new insight that DDR2 might promote metabolism in adipocyte cells is very interesting, but more experiments will be needed to elucidate the direct relation between DDR2 and adipose-derived hormones. Taken together, our data demonstrated that DDR2 might play a systemic role in the regulation of body size thorough skeletal formation and fat metabolism.

  7. Body Size Preference of Marine Animals in Relation to Extinction Selectivity

    NASA Astrophysics Data System (ADS)

    Sriram, A.; Idgunji, S.; Heim, N. A.; Payne, J.

    2014-12-01

    Our project encompasses an extremely specific aspect in relation to the five mass extinctions in geologic history. We asked ourselves whether larger or smaller body sizes would be better suited for surviving a mass extinction. To conduct research for our project, we used the body sizes of 17,172 marine animal genera as our primary data. These animals include echinoderms, arthropods, chordates, mollusks, and brachiopods. These creatures are perfect model organisms in terms of finding data on them because they have an excellent fossil record, and are well documented. We focused on the mean body size of these animals before and after each of the five mass extinctions (end-Ordovician, Late Devonian, end-Permian, end-Triassic, and end-Cretaceous). Our hypothesis was that the average biovolume of animals increased after each of the extinctions, with the mean size being greater after than it was before. Our size data is from the Ellis & Messina Catalogue of Ostracoda and the Treatise on Invertebrate Paleontology. We obtained stratigraphic range data The Treatise and Sepkoski (2002). In our analyses, we compared the mean size of the different animal genera before and after each extinction event. We further partitioned size change across mass extinction boundaries into three categories: the surviving genera, the extinct genera, and the newly originating genera that came about after the extinction. According to our analyses, the mean sizes did not change significantly from the genera living during the stages before the extinctions and after the extinctions. From our results, we can assume that there were not enough major increases in the overall volume of the organisms to warrant a definite conclusion that extinctions lead to larger body sizes. Further support for our findings came from the T-tests in our R code. Only the Cretaceous period showed true evidence for size changing because of the extinction; in this case, the mean size decreased. T-tests for the Cretaceous

  8. Finite size scaling for the many-body-localization transition: finite-size-pseudo-critical points of individual eigenstates

    NASA Astrophysics Data System (ADS)

    Monthus, Cécile

    2016-12-01

    To understand the finite-size-scaling properties of phases transitions in classical and quantum models in the presence of quenched disorder, it has proven to be fruitful to introduce the notion of a finite-size-pseudo-critical point in each disordered sample and to analyze its sample-to-sample fluctuations as a function of the size. For the many-body-localization transition, where very strong eigenstate-to-eigenstate fluctuations have been numerically reported even within a given disordered sample at a given energy density (Yu, Luitz and Clark 2016 arXiv:1606.01260 and Khemani, Lim, Sheng and Huse 2016 arXiv:1607.05756), it seems thus useful to introduce the notion of a finite-size-pseudo-critical point for each individual eigenstate and to study its eigenstate-to-eigenstate fluctuations governed by the correlation length exponent ν. The scaling properties of critical eigenstates are also expected to appear much more clearly if one considers each eigenstate at its finite-size-pseudo-critical point, where it is ‘truly critical’, while standard averages over eigenstates and samples in the critical region actually see a mixture of states that are effectively either localized or delocalized.

  9. The Mind-Body Connection - Can Prolonged Stress Affect Whether Breast Cancer Returns?

    MedlinePlus

    ... Past Issues The Mind-Body Connection Can Prolonged Stress Affect Whether Breast Cancer Returns? Past Issues / Winter ... traumatic life events. The categories ranged from traumatic stress to some stress to no significant stress. According ...

  10. Biology, not environment, drives major patterns in maximum tetrapod body size through time.

    PubMed

    Sookias, Roland B; Benson, Roger B J; Butler, Richard J

    2012-08-23

    Abiotic and biological factors have been hypothesized as controlling maximum body size of tetrapods and other animals through geological time. We analyse the effects of three abiotic factors--oxygen, temperature and land area--on maximum size of Permian-Jurassic archosauromorphs and therapsids, and Cenozoic mammals, using time series generalized least-squares regression models. We also examine maximum size growth curves for the Permian-Jurassic data by comparing fits of Gompertz and logistic models. When serial correlation is removed, we find no robust correlations, indicating that these environmental factors did not consistently control tetrapod maximum size. Gompertz models--i.e. exponentially decreasing rate of size increase at larger sizes--fit maximum size curves far better than logistic models. This suggests that biological limits such as reduced fecundity and niche space availability become increasingly limiting as larger sizes are reached. Environmental factors analysed may still have imposed an upper limit on tetrapod body size, but any environmentally imposed limit did not vary substantially during the intervals examined despite variation in these environmental factors.

  11. Environmental and biotic controls on the evolutionary history of insect body size

    PubMed Central

    Clapham, Matthew E.; Karr, Jered A.

    2012-01-01

    Giant insects, with wingspans as large as 70 cm, ruled the Carboniferous and Permian skies. Gigantism has been linked to hyperoxic conditions because oxygen concentration is a key physiological control on body size, particularly in groups like flying insects that have high metabolic oxygen demands. Here we show, using a dataset of more than 10,500 fossil insect wing lengths, that size tracked atmospheric oxygen concentrations only for the first 150 Myr of insect evolution. The data are best explained by a model relating maximum size to atmospheric environmental oxygen concentration (pO2) until the end of the Jurassic, and then at constant sizes, independent of oxygen fluctuations, during the Cretaceous and, at a smaller size, the Cenozoic. Maximum insect size decreased even as atmospheric pO2 rose in the Early Cretaceous following the evolution and radiation of early birds, particularly as birds acquired adaptations that allowed more agile flight. A further decrease in maximum size during the Cenozoic may relate to the evolution of bats, the Cretaceous mass extinction, or further specialization of flying birds. The decoupling of insect size and atmospheric pO2 coincident with the radiation of birds suggests that biotic interactions, such as predation and competition, superseded oxygen as the most important constraint on maximum body size of the largest insects. PMID:22665762

  12. From the Cover: Environmental and biotic controls on the evolutionary history of insect body size

    NASA Astrophysics Data System (ADS)

    Clapham, Matthew E.; Karr, Jered A.

    2012-07-01

    Giant insects, with wingspans as large as 70 cm, ruled the Carboniferous and Permian skies. Gigantism has been linked to hyperoxic conditions because oxygen concentration is a key physiological control on body size, particularly in groups like flying insects that have high metabolic oxygen demands. Here we show, using a dataset of more than 10,500 fossil insect wing lengths, that size tracked atmospheric oxygen concentrations only for the first 150 Myr of insect evolution. The data are best explained by a model relating maximum size to atmospheric environmental oxygen concentration (pO2) until the end of the Jurassic, and then at constant sizes, independent of oxygen fluctuations, during the Cretaceous and, at a smaller size, the Cenozoic. Maximum insect size decreased even as atmospheric pO2 rose in the Early Cretaceous following the evolution and radiation of early birds, particularly as birds acquired adaptations that allowed more agile flight. A further decrease in maximum size during the Cenozoic may relate to the evolution of bats, the Cretaceous mass extinction, or further specialization of flying birds. The decoupling of insect size and atmospheric pO2 coincident with the radiation of birds suggests that biotic interactions, such as predation and competition, superseded oxygen as the most important constraint on maximum body size of the largest insects.

  13. Body-size spectra of biofilm-dwelling protozoa and their seasonal shift in coastal ecosystems.

    PubMed

    Zhao, Lu; Xu, Guangjian; Wang, Zheng; Xu, Henglong

    2016-10-01

    Community-based assessment of protozoa is usually performed at a taxon-dependent resolution. As an inherent 'taxon-free' trait, however, body-size spectrum has proved to be a highly informative indicator to summarize the functional structure of a community in both community research and monitoring programs in aquatic ecosystems. To demonstrate the relationships between the taxon-free resolution of protozoan communities and water conditions, the body-size spectra of biofilm-dwelling protozoa and their seasonal shift and environmental drivers were explored based on an annual dataset collected monthly from coastal waters of the Yellow Sea, northern China. Body sizes were calculated in equivalent spherical diameter (ESD). Among a total of 8 body-size ranks, S2 (19-27μm), S3 (28-36μm), S4 (37-50μm) and S5 (53-71μm) were the top four levels in frequency of occurrence, while rank S1 (13-17μm), S2 and S4 were the dominant levels in abundance. These dominants showed a clear seasonal succession: S2/S4 (spring)→S2/S4 (summer)→S4 (autumn)→S2 (winter) in frequency of occurrence; S1 (spring)→S4 (summer)→S2 (autumn)→S1 (winter) in abundance. Bootstrapped average analysis showed a clear seasonal shift in body-size spectra of the protozoa during a 1-year cycle, and the best-matching analysis demonstrated that the temporal variations in frequency of occurrence and abundance were significantly correlated with water temperature, pH, dissolved oxygen (DO), alone or in combination with chemical oxygen demand (COD) and nutrients. Thus, the body-size spectra of biofilm-dwelling protozoa were seasonally shaped and might be used as a time and cost efficient bioindicator of water quality in marine ecosystems.

  14. The Relationship between Perceived and Ideal Body Size and Body Mass Index in 3rd-Grade Low Socioeconomic Hispanic Children

    ERIC Educational Resources Information Center

    Fisher, Allison; Lange, Mary Anne; Young-Cureton, Virginia; Canham, Daryl

    2005-01-01

    Very little is known about body satisfaction among minority children. This study examined the relationship between perceived and actual body size and Body Mass Index among 43 low-socioeconomic Hispanic 3rd-graders. Researchers measured participants' Body Mass Index; students self-reported Perceived Ideal Self Image and Perceived Actual Self Image…

  15. Cultural constructions of "obesity": understanding body size, social class and gender in Morocco.

    PubMed

    Batnitzky, Adina K

    2011-01-01

    This article presents data from an in-depth qualitative study of overweight and diabetic women in Morocco, a North African country experiencing a rapid increase in obesity according to national statistics. This case study explores the heterogeneous relationship among health, culture and religion in Morocco by highlighting the relationship between the intricacies of women's everyday lives and their body sizes. My findings suggest that although the Body Mass Index (BMI) of adult women has been documented to have increased in Morocco along with other macroeconomic changes (i.e., increases in urbanization, etc.), "obesity" has yet to be universally medicalized in the Moroccan context. As such women do not generally utilize a medicalized concept of obesity in reference to their larger body sizes. Rather, cultural constructions of "obesity" are understood through cultural understandings of a larger body size, religious beliefs about health and illness, and the nature of women's religious participation. This stands in contrast to dominant accounts about the region that promote an overall veneration of a larger body size for women.

  16. Selection does not favor larger body size at lower temperature in a seed-feeding beetle.

    PubMed

    Stillwell, R Craig; Moya-Laraño, Jordi; Fox, Charles W

    2008-10-01

    Body size of many animals increases with increasing latitude, a phenomenon known as Bergmann's rule (Bergmann clines). Latitudinal gradients in mean temperature are frequently assumed to be the underlying cause of this pattern because temperature covaries systematically with latitude, but whether and how temperature mediates selection on body size is unclear. To test the hypothesis that the "relative" advantage of being larger is greatest at cooler temperatures we compare the fitness of replicate lines of the seed beetle, Stator limbatus, for which body size was manipulated via artificial selection ("Large,"Control," and "Small" lines), when raised at low (22 degrees C) and high (34 degrees C) temperatures. Large-bodied beetles (Large lines) took the longest to develop but had the highest lifetime fecundity, and highest fitness (r(C)), at both low and high temperatures. However, the relative difference between the Large and Small lines did not change with temperature (replicate 2) or was greatest at high temperature (replicate 1), contrary to the prediction that the fitness advantage of being large relative to being small will decline with increasing temperature. Our results are consistent with two previous studies of this seed beetle, but inconsistent with prior studies that suggest that temperature-mediated selection on body size is a major contributor to the production of Bergmann clines. We conclude that other environmental and ecological variables that covary with latitude are more likely to produce the gradient in natural selection responsible for generating Bergmann clines.

  17. Body size and extinction risk in terrestrial mammals above the species level.

    PubMed

    Tomiya, Susumu

    2013-12-01

    Mammalian body mass strongly correlates with life history and population properties at the scale of mouse to elephant. Large body size is thus often associated with elevated extinction risk. I examined the North American fossil record (28-1 million years ago) of 276 terrestrial genera to uncover the relationship between body size and extinction probability above the species level. Phylogenetic comparative analysis revealed no correlation between sampling-adjusted durations and body masses ranging 7 orders of magnitude, an observation that was corroborated by survival analysis. Most of the ecological and temporal groups within the data set showed the same lack of relationship. Size-biased generic extinctions do not constitute a general feature of the Holarctic mammalian faunas in the Neogene. Rather, accelerated loss of large mammals occurred during intervals that experienced combinations of regional aridification and increased biomic heterogeneity within continents. The latter phenomenon is consistent with the macroecological prediction that large geographic ranges are critical to the survival of large mammals in evolutionary time. The frequent lack of size selectivity in generic extinctions can be reconciled with size-biased species loss if extinctions of large and small mammals at the species level are often driven by ecological perturbations of different spatial and temporal scales, while those at the genus level are more synchronized in time as a result of fundamental, multiscale environmental shifts.

  18. Relationships between abiotic environment, plant functional traits, and animal body size at Mount Kilimanjaro, Tanzania

    PubMed Central

    Classen, Alice; Ferger, Stefan; Helbig-Bonitz, Maria; Peters, Marcell; Böhning-Gaese, Katrin; Steffan-Dewenter, Ingolf; Kleyer, Michael

    2017-01-01

    The effect-response framework states that plant functional traits link the abiotic environment to ecosystem functioning. One ecosystem property is the body size of the animals living in the system, which is assumed to depend on temperature or resource availability, among others. For primary consumers, resource availability may directly be related to plant traits, while for secondary consumers the relationship is indirect. We used plant traits to describe resource availability along an elevational gradient on Mount Kilimanjaro, Tanzania. Using structural equation models, we determined the response of plant traits to changes in precipitation, temperature and disturbance with and assessed whether abiotic conditions or community-weighted means of plant traits are stronger predictors of the mean size of bees, moths, frugivorous birds, and insectivorous birds. Traits indicating tissue density and nutrient content strongly responded to variations in precipitation, temperature and disturbance. They had direct effects on pollination and fruit traits. However, the average body sizes of the animal groups considered could only be explained by temperature and habitat structure, not by plant traits. Our results demonstrate a strong link between traits and the abiotic environment, but suggest that temperature is the most relevant predictor of mean animal body size. Community-weighted means of plant traits and body sizes appear unsuitable to capture the complexity of plant-animal interactions. PMID:28319155

  19. Lifespan, growth rate, and body size across latitude in marine Bivalvia, with implications for Phanerozoic evolution.

    PubMed

    Moss, David K; Ivany, Linda C; Judd, Emily J; Cummings, Patrick W; Bearden, Claire E; Kim, Woo-Jun; Artruc, Emily G; Driscoll, Jeremy R

    2016-08-17

    Mean body size in marine animals has increased more than 100-fold since the Cambrian, a discovery that brings to attention the key life-history parameters of lifespan and growth rate that ultimately determine size. Variation in these parameters is not well understood on the planet today, much less in deep time. Here, we present a new global database of maximum reported lifespan and shell growth coupled with body size data for 1 148 populations of marine bivalves and show that (i) lifespan increases, and growth rate decreases, with latitude, both across the group as a whole and within well-sampled species, (ii) growth rate, and hence metabolic rate, correlates inversely with lifespan, and (iii) opposing trends in lifespan and growth combined with high variance obviate any demonstrable pattern in body size with latitude. Our observations suggest that the proposed increase in metabolic activity and demonstrated increase in body size of organisms over the Phanerozoic should be accompanied by a concomitant shift towards faster growth and/or shorter lifespan in marine bivalves. This prediction, testable from the fossil record, may help to explain one of the more fundamental patterns in the evolutionary and ecological history of animal life on this planet.

  20. Relationships between abiotic environment, plant functional traits, and animal body size at Mount Kilimanjaro, Tanzania.

    PubMed

    Schellenberger Costa, David; Classen, Alice; Ferger, Stefan; Helbig-Bonitz, Maria; Peters, Marcell; Böhning-Gaese, Katrin; Steffan-Dewenter, Ingolf; Kleyer, Michael

    2017-01-01

    The effect-response framework states that plant functional traits link the abiotic environment to ecosystem functioning. One ecosystem property is the body size of the animals living in the system, which is assumed to depend on temperature or resource availability, among others. For primary consumers, resource availability may directly be related to plant traits, while for secondary consumers the relationship is indirect. We used plant traits to describe resource availability along an elevational gradient on Mount Kilimanjaro, Tanzania. Using structural equation models, we determined the response of plant traits to changes in precipitation, temperature and disturbance with and assessed whether abiotic conditions or community-weighted means of plant traits are stronger predictors of the mean size of bees, moths, frugivorous birds, and insectivorous birds. Traits indicating tissue density and nutrient content strongly responded to variations in precipitation, temperature and disturbance. They had direct effects on pollination and fruit traits. However, the average body sizes of the animal groups considered could only be explained by temperature and habitat structure, not by plant traits. Our results demonstrate a strong link between traits and the abiotic environment, but suggest that temperature is the most relevant predictor of mean animal body size. Community-weighted means of plant traits and body sizes appear unsuitable to capture the complexity of plant-animal interactions.

  1. Macroevolutionary patterns of bumblebee body size: detecting the interplay between natural and sexual selection

    PubMed Central

    del Castillo, Raúl Cueva; Fairbairn, Daphne J

    2012-01-01

    Bumblebees and other eusocial bees offer a unique opportunity to analyze the evolution of body size differences between sexes. The workers, being sterile females, are not subject to selection for reproductive function and thus provide a natural control for parsing the effects of selection on reproductive function (i.e., sexual and fecundity selection) from other natural selection. Using a phylogenetic comparative approach, we explored the allometric relationships among queens, males, and workers in 70 species of bumblebees (Bombus sp.). We found hyperallometry in thorax width for males relative to workers, indicating greater evolutionary divergence of body size in males than in sterile females. This is consistent with the hypothesis that selection for reproductive function, most probably sexual selection, has caused divergence in male size among species. The slope for males on workers was significantly steeper than that for queens on workers and the latter did not depart from isometry, providing further evidence of greater evolutionary divergence in male size than female size, and no evidence that reproductive selection has accelerated divergence of females. We did not detect significant hyperallometry when male size was regressed directly on queen size and our results thus add the genus Bombus to the increasing list of clades that have female-larger sexual size dimorphism and do not conform to Rensch's rule when analyzed according to standard methodology. Nevertheless, by using worker size as a common control, we were able to demonstrate that bumblee species do show the evolutionary pattern underlying Rensch's rule, that being correlated evolution of body size in males and females, but with greater evolutionary divergence in males. PMID:22408725

  2. Cross Modal Perception of Body Size in Domestic Dogs (Canis familiaris)

    PubMed Central

    McComb, Karen

    2011-01-01

    While the perception of size-related acoustic variation in animal vocalisations is well documented, little attention has been given to how this information might be integrated with corresponding visual information. Using a cross-modal design, we tested the ability of domestic dogs to match growls resynthesised to be typical of either a large or a small dog to size-matched models. Subjects looked at the size-matched model significantly more often and for a significantly longer duration than at the incorrect model, showing that they have the ability to relate information about body size from the acoustic domain to the appropriate visual category. Our study suggests that the perceptual and cognitive mechanisms at the basis of size assessment in mammals have a multisensory nature, and calls for further investigations of the multimodal processing of size information across animal species. PMID:21359228

  3. Completeness of the fossil record: Estimating losses due to small body size

    NASA Astrophysics Data System (ADS)

    Cooper, Roger A.; Maxwell, Phillip A.; Crampton, James S.; Beu, Alan G.; Jones, Craig M.; Marshall, Bruce A.

    2006-04-01

    Size bias in the fossil record limits its use for interpreting patterns of past biodiversity and ecological change. Using comparative size frequency distributions of exceptionally good regional records of New Zealand Holocene and Cenozoic Mollusca in museum archive collections, we derive first-order estimates of the magnitude of the bias against small body size and the effect of this bias on completeness of the fossil record. Our database of 3907 fossil species represents an original living pool of 9086 species, from which ˜36% have been removed by size culling, 27% from the smallest size class (<5 mm). In contrast, non-size-related losses compose only 21% of the total. In soft rocks, the loss of small taxa can be reduced by nearly 50% through the employment of exhaustive collection and preparation techniques.

  4. Penis size interacts with body shape and height to influence male attractiveness.

    PubMed

    Mautz, Brian S; Wong, Bob B M; Peters, Richard A; Jennions, Michael D

    2013-04-23

    Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory sexual selection for characteristics that increase a male's relative fertilization success. There could, however, also be direct precopulatory female mate choice based on male genital traits. Before clothing, the nonretractable human penis would have been conspicuous to potential mates. This observation has generated suggestions that human penis size partly evolved because of female choice. Here we show, based upon female assessment of digitally projected life-size, computer-generated images, that penis size interacts with body shape and height to determine male sexual attractiveness. Positive linear selection was detected for penis size, but the marginal increase in attractiveness eventually declined with greater penis size (i.e., quadratic selection). Penis size had a stronger effect on attractiveness in taller men than in shorter men. There was a similar increase in the positive effect of penis size on attractiveness with a more masculine body shape (i.e., greater shoulder-to-hip ratio). Surprisingly, larger penis size and greater height had almost equivalent positive effects on male attractiveness. Our results support the hypothesis that female mate choice could have driven the evolution of larger penises in humans. More broadly, our results show that precopulatory sexual selection can play a role in the evolution of genital traits.

  5. Biology, not environment, drives major patterns in maximum tetrapod body size through time

    PubMed Central

    Sookias, Roland B.; Benson, Roger B. J.; Butler, Richard J.

    2012-01-01

    Abiotic and biological factors have been hypothesized as controlling maximum body size of tetrapods and other animals through geological time. We analyse the effects of three abiotic factors—oxygen, temperature and land area—on maximum size of Permian–Jurassic archosauromorphs and therapsids, and Cenozoic mammals, using time series generalized least-squares regression models. We also examine maximum size growth curves for the Permian–Jurassic data by comparing fits of Gompertz and logistic models. When serial correlation is removed, we find no robust correlations, indicating that these environmental factors did not consistently control tetrapod maximum size. Gompertz models—i.e. exponentially decreasing rate of size increase at larger sizes—fit maximum size curves far better than logistic models. This suggests that biological limits such as reduced fecundity and niche space availability become increasingly limiting as larger sizes are reached. Environmental factors analysed may still have imposed an upper limit on tetrapod body size, but any environmentally imposed limit did not vary substantially during the intervals examined despite variation in these environmental factors. PMID:22513278

  6. Body size and the small branch niche: using marsupial ontogeny to model primate locomotor evolution.

    PubMed

    Shapiro, Liza J; Young, Jesse W; VandeBerg, John L

    2014-03-01

    Recently proposed ancestral locomotor and morphological 'stages' leading to the evolution of primates have emphasized small body size, and a transition from a clawed non-grasping stage, to a clawed, grasping stage with clawless opposable hallux, to a fully-nailed primate with grasping extremities. This evolutionary transition was presumably associated with frequent use of the small branch niche. To model elements of these evolutionary transitions, we investigate how body size, substrate size, substrate orientation and grasping morphology interact to influence quadrupedal kinematics within and between ontogenetic samples of two small-bodied marsupials, one arboreal (Petaurus breviceps) and the other mainly terrestrial (Monodelphis domestica). Longitudinal morphometric and kinematic data were collected from four juvenile P. breviceps (33-75 g) and two juvenile M. domestica (18-95 g) walking across poles of three diameters (2.5, 1.0, and 0.5 cm) and three orientations (horizontal, 30° incline, 30° decline). The two species responded similarly to some substrate conditions, but diverged in response to others. Kinematic divergence between the two species reflects Monodelphis' relatively shorter digits, reduced grasping ability and greater need for stabilizing mechanisms on narrow substrates. At a given relative body size or pole orientation, Monodelphis used higher limb duty factors, more limbs in support per stride, lower limb phases, and in some conditions, faster speeds compared with Petaurus. Interspecific differences were the least distinct on declined poles, highlighting the particular challenge of this substrate condition, even for arboreally adapted species. Small-bodied, arboreal primate ancestors would likely have employed the kinematic mechanisms common to our model taxa, but those with enhanced grasping adaptations would most likely not have required the increased level of stabilizing mechanisms exhibited by Monodelphis. Thus, using these two species

  7. Potential enhanced ability of giant squid to detect sperm whales is an exaptation tied to their large body size.

    PubMed

    Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Wainwright, Peter C

    2013-10-15

    It has been hypothesized that sperm whale predation is the driver of eye size evolution in giant squid. Given that the eyes of giant squid have the size expected for a squid this big, it is likely that any enhanced ability of giant squid to detect whales is an exaptation tied to their body size. Future studies should target the mechanism behind the evolution of large body size, not eye size. Reconstructions of the evolutionary history of selective regime, eye size, optical performance, and body size will improve the understanding of the evolution of large eyes in large ocean animals.

  8. 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

  9. Resource partitioning or reproductive isolation: the ecological role of body size differences among closely related species in sympatry.

    PubMed

    Okuzaki, Yutaka; Takami, Yasuoki; Sota, Teiji

    2010-03-01

    1. Body size differences among coexisting related species are common, but the actual effect of these differences in mitigating interspecific interactions, such as resource competition and reproductive interference, is poorly understood. 2. Local assemblages of the ground beetle genus Carabus (subgenus Ohomopterus) typically consist of two or more species of varying sizes. Through foraging and mating experiments using four Ohomopterus species in parapatry and sympatry, we examined whether interspecific body size differences are effective in partitioning food resources or reducing reproductive interference. 3. Because larval Ohomopterus feed exclusively on earthworms, body size differences may be related to partitioning earthworms of different sizes. However, larvae did not exhibit differences in selectivity or attack success on earthworms of different sizes based on larval body size, indicating little possibility of partitioning food by body size. 4. In contrast, interspecific mating behaviours, such as mate recognition, mounting, and copulation, were hindered when body size differences were large; copulation was frequently accomplished between parapatric species with smaller body size differences. 5. These results suggest that body size differences between species effectively reduce reproductive interference, rather than resource competition. Although body size differences in coexisting closely related species have been considered to function in resource partitioning, they may function primarily in reproductive isolation and thereby facilitate coexistence of species.

  10. Acoustic correlates of body size and individual identity in banded penguins.

    PubMed

    Favaro, Livio; Gamba, Marco; Gili, Claudia; Pessani, Daniela

    2017-01-01

    Animal vocalisations play a role in individual recognition and mate choice. In nesting penguins, acoustic variation in vocalisations originates from distinctiveness in the morphology of the vocal apparatus. Using the source-filter theory approach, we investigated vocal individuality cues and correlates of body size and mass in the ecstatic display songs the Humboldt and Magellanic penguins. We demonstrate that both fundamental frequency (f0) and formants (F1-F4) are essential vocal features to discriminate among individuals. However, we show that only duration and f0 are honest indicators of the body size and mass, respectively. We did not find any effect of body dimension on formants, formant dispersion nor estimated vocal tract length of the emitters. Overall, our findings provide the first evidence that the resonant frequencies of the vocal tract do not correlate with body size in penguins. Our results add important information to a growing body of literature on the role of the different vocal parameters in conveying biologically meaningful information in bird vocalisations.

  11. Acoustic correlates of body size and individual identity in banded penguins

    PubMed Central

    Gamba, Marco; Gili, Claudia; Pessani, Daniela

    2017-01-01

    Animal vocalisations play a role in individual recognition and mate choice. In nesting penguins, acoustic variation in vocalisations originates from distinctiveness in the morphology of the vocal apparatus. Using the source-filter theory approach, we investigated vocal individuality cues and correlates of body size and mass in the ecstatic display songs the Humboldt and Magellanic penguins. We demonstrate that both fundamental frequency (f0) and formants (F1-F4) are essential vocal features to discriminate among individuals. However, we show that only duration and f0 are honest indicators of the body size and mass, respectively. We did not find any effect of body dimension on formants, formant dispersion nor estimated vocal tract length of the emitters. Overall, our findings provide the first evidence that the resonant frequencies of the vocal tract do not correlate with body size in penguins. Our results add important information to a growing body of literature on the role of the different vocal parameters in conveying biologically meaningful information in bird vocalisations. PMID:28199318

  12. Physical Activity, Body Size, Intentional Weight Loss and Breast Cancer Risk: Fellowship

    DTIC Science & Technology

    2000-10-01

    Incident cases of invasive endome - mine whether the relation between diabetes and endo- trial cancer (diagnosed between 1991 and 1994) were metrial cancer...with an increased risk of endome - increase in risk above that attributed to body size trial cancer that decreased as duration increased (p alone

  13. Body size evolution in Mesozoic birds: little evidence for Cope's rule.

    PubMed

    Butler, R J; Goswami, A

    2008-11-01

    Cope's rule, the tendency towards evolutionary increases in body size, is a long-standing macroevolutionary generalization that has the potential to provide insights into directionality in evolution; however, both the definition and identification of Cope's rule are controversial and problematic. A recent study [J. Evol. Biol. 21 (2008) 618] examined body size evolution in Mesozoic birds, and claimed to have identified evidence of Cope's rule occurring as a result of among-lineage species sorting. We here reassess the results of this study, and additionally carry out novel analyses testing for within-lineage patterns in body size evolution in Mesozoic birds. We demonstrate that the nonphylogenetic methods used by this previous study cannot distinguish between among- and within-lineage processes, and that statistical support for their results and conclusions is extremely weak. Our ancestor-descendant within-lineage analyses explicitly incorporate recent phylogenetic hypotheses and find little compelling evidence for Cope's rule. Cope's rule is not supported in Mesozoic birds by the available data, and body size evolution currently provides no insights into avian survivorship through the Cretaceous-Paleogene mass extinction.

  14. Decline in top predator body size and changing climate alter trophic structure in an oceanic ecosystem.

    PubMed

    Shackell, Nancy L; Frank, Kenneth T; Fisher, Jonathan A D; Petrie, Brian; Leggett, William C

    2010-05-07

    Globally, overfishing large-bodied groundfish populations has resulted in substantial increases in their prey populations. Where it has been examined, the effects of overfishing have cascaded down the food chain. In an intensively fished area on the western Scotian Shelf, Northwest Atlantic, the biomass of prey species increased exponentially (doubling time of 11 years) even though the aggregate biomass of their predators remained stable over 38 years. Concomitant reductions in herbivorous zooplankton and increases in phytoplankton were also evident. This anomalous trophic pattern led us to examine how declines in predator body size (approx. 60% in body mass since the early 1970s) and climatic regime influenced lower trophic levels. The increase in prey biomass was associated primarily with declines in predator body size and secondarily to an increase in stratification. Sea surface temperature and predator biomass had no influence. A regression model explained 65 per cent of prey biomass variability. Trait-mediated effects, namely a reduction in predator size, resulted in a weakening of top predation pressure. Increased stratification may have enhanced growing conditions for prey fish. Size-selective harvesting under changing climatic conditions initiated a trophic restructuring of the food chain, the effects of which may have influenced three trophic levels.

  15. The evolution of placental mammal body sizes: evolutionary history, form, and function.

    PubMed

    Lovegrove, Barry G; Haines, Linda

    2004-01-01

    The unimodal, right-skewed distribution, most frequently identified in contemporary descriptions of placental mammal body size distributions, masks an underlying multidistribution structure; a long-term evolutionary process that has generated a concatenation of two or three frequency distributions specific to locomotory modes (plantigrade, digitigrade and unguligrade). The Afrotropical assemblages are bimodal, with a tendency towards trimodality, whereas the Nearctic assemblage is unimodal. However, mixtures of two and three normal distributions fitted the Nearctic data well, suggesting a multidistribution structure masked by disproportionate species numbers within locomotory modes. Differences in proportional species numbers within modes between assemblages may reflect the evolutionary history of form and function. However, common interassemblage predictions of such proportions in contemporary distributions may be disguised by the relative severity of the Pleistocene megafaunal extinction (patterns supported by the fossil record), geographical scale, and taxonomic composition. A species gap occurs at body sizes around 1 kg at the interface between the largest plantigrade mammals and the smallest digitigrade mammals, coincident with the minimum interspecific variance of basal metabolic rate. In terms of the evolution of the optimal body size in the trade-off between mortality and production, there may be good historical and evolutionary reasons why we should not expect optimization to produce the same results in different zoogeographical assemblages. Moreover, the evolution of diverse mammalian forms and functions, especially with respect to predator-prey interactions and diet, render a single body size optimum untenable in the search for an energetic definition of fitness.

  16. Maternal body size influences offspring immune configuration in an oviparous snake

    PubMed Central

    Brown, Gregory P.

    2016-01-01

    Like most ectothermic vertebrates, keelback snakes (Tropidonophis mairii) do not exhibit parental care. Thus, offspring must possess an immune system capable of dealing with challenges such as pathogens, without assistance from an attendant parent. We know very little about immune system characteristics of neonatal reptiles, including the magnitude of heritability and other maternal influences. To identify sources of variation in circulating white blood cell (WBC) concentrations and differentials, we examined blood smears from 246 hatchling snakes and their field-caught mothers. WBC concentrations were lower in hatchlings than in adults, and hatchlings had more basophils and fewer azurophils than adults. A hatchling keelback's WBC differential was also influenced by its sex and body size. Although hatchling WBC measures exhibited negligible heritability, they were strongly influenced by maternal body size and parasite infection (but not by maternal body condition, relative clutch mass or time in captivity). Larger mothers produced offspring with more azurophils and fewer lymphocytes. The mechanisms and consequences of WBC variation are currently unknown, but if these maternal effects enhance offspring fitness, the impact of maternal body size on reproductive success may be greater than expected simply from allometric increases in the numbers and sizes of progeny. PMID:27069670

  17. Decline in top predator body size and changing climate alter trophic structure in an oceanic ecosystem

    PubMed Central

    Shackell, Nancy L.; Frank, Kenneth T.; Fisher, Jonathan A. D.; Petrie, Brian; Leggett, William C.

    2010-01-01

    Globally, overfishing large-bodied groundfish populations has resulted in substantial increases in their prey populations. Where it has been examined, the effects of overfishing have cascaded down the food chain. In an intensively fished area on the western Scotian Shelf, Northwest Atlantic, the biomass of prey species increased exponentially (doubling time of 11 years) even though the aggregate biomass of their predators remained stable over 38 years. Concomitant reductions in herbivorous zooplankton and increases in phytoplankton were also evident. This anomalous trophic pattern led us to examine how declines in predator body size (approx. 60% in body mass since the early 1970s) and climatic regime influenced lower trophic levels. The increase in prey biomass was associated primarily with declines in predator body size and secondarily to an increase in stratification. Sea surface temperature and predator biomass had no influence. A regression model explained 65 per cent of prey biomass variability. Trait-mediated effects, namely a reduction in predator size, resulted in a weakening of top predation pressure. Increased stratification may have enhanced growing conditions for prey fish. Size-selective harvesting under changing climatic conditions initiated a trophic restructuring of the food chain, the effects of which may have influenced three trophic levels. PMID:20031989

  18. Effects of body size and lifestyle on evolution of mammal life histories.

    PubMed

    Sibly, Richard M; Brown, James H

    2007-11-06

    It has recently been proposed that life-history evolution is subject to a fundamental size-dependent constraint. This constraint limits the rate at which biomass can be produced so that production per unit of body mass is inevitably slower in larger organisms than in smaller ones. Here we derive predictions for how changes in body size and production rates evolve in different lifestyles subject to this constraint. Predictions are tested by using data on the mass of neonate tissue produced per adult per year in 637 placental mammal species and are generally supported. Compared with terrestrial insectivores with generalized primitive traits, mammals that have evolved more specialized lifestyles have divergent mass-specific production rates: (i) increased in groups that specialize on abundant and reliable foods: grazing and browsing herbivores (artiodactyls, lagomorphs, perissodactyls, and folivorous rodents) and flesh-eating marine mammals (pinnipeds, cetaceans); and (ii) decreased in groups that have lifestyles with reduced death rates: bats, primates, arboreal, fossorial, and desert rodents, bears, elephants, and rhinos. Convergent evolution of groups with similar lifestyles is common, so patterns of productivity across mammalian taxa reflect both ecology and phylogeny. The overall result is that groups with different lifestyles have parallel but offset relationships between production rate and body size. These results shed light on the evolution of the fast-slow life-history continuum, suggesting that variation occurs along two axes corresponding to body size and lifestyle.

  19. Short-term exposure to predation affects body elemental composition, climbing speed and survival ability in Drosophila melanogaster

    PubMed Central

    Eichler Inwood, Sarah; Trakimas, Giedrius; Krams, Ronalds; Burghardt, Gordon M.; Butler, David M.; Luoto, Severi; Krama, Tatjana

    2016-01-01

    Factors such as temperature, habitat, larval density, food availability and food quality substantially affect organismal development. In addition, risk of predation has a complex impact on the behavioural and morphological life history responses of prey. Responses to predation risk seem to be mediated by physiological stress, which is an adaptation for maintaining homeostasis and improving survivorship during life-threatening situations. We tested whether predator exposure during the larval phase of development has any influence on body elemental composition, energy reserves, body size, climbing speed and survival ability of adult Drosophila melanogaster. Fruit fly larvae were exposed to predation by jumping spiders (Phidippus apacheanus), and the percentage of carbon (C) and nitrogen (N) content, extracted lipids, escape response and survival were measured from predator-exposed and control adult flies. The results revealed predation as an important determinant of adult phenotype formation and survival ability. D. melanogaster reared together with spiders had a higher concentration of body N (but equal body C), a lower body mass and lipid reserves, a higher climbing speed and improved adult survival ability. The results suggest that the potential of predators to affect the development and the adult phenotype of D. melanogaster is high enough to use predators as a more natural stimulus in laboratory experiments when testing, for example, fruit fly memory and learning ability, or when comparing natural populations living under different predation pressures. PMID:27602281

  20. Short-term exposure to predation affects body elemental composition, climbing speed and survival ability in Drosophila melanogaster.

    PubMed

    Krams, Indrikis; Eichler Inwood, Sarah; Trakimas, Giedrius; Krams, Ronalds; Burghardt, Gordon M; Butler, David M; Luoto, Severi; Krama, Tatjana

    2016-01-01

    Factors such as temperature, habitat, larval density, food availability and food quality substantially affect organismal development. In addition, risk of predation has a complex impact on the behavioural and morphological life history responses of prey. Responses to predation risk seem to be mediated by physiological stress, which is an adaptation for maintaining homeostasis and improving survivorship during life-threatening situations. We tested whether predator exposure during the larval phase of development has any influence on body elemental composition, energy reserves, body size, climbing speed and survival ability of adult Drosophila melanogaster. Fruit fly larvae were exposed to predation by jumping spiders (Phidippus apacheanus), and the percentage of carbon (C) and nitrogen (N) content, extracted lipids, escape response and survival were measured from predator-exposed and control adult flies. The results revealed predation as an important determinant of adult phenotype formation and survival ability. D. melanogaster reared together with spiders had a higher concentration of body N (but equal body C), a lower body mass and lipid reserves, a higher climbing speed and improved adult survival ability. The results suggest that the potential of predators to affect the development and the adult phenotype of D. melanogaster is high enough to use predators as a more natural stimulus in laboratory experiments when testing, for example, fruit fly memory and learning ability, or when comparing natural populations living under different predation pressures.

  1. Illusory ownership of a virtual child body causes overestimation of object sizes and implicit attitude changes.

    PubMed

    Banakou, Domna; Groten, Raphaela; Slater, Mel

    2013-07-30

    An illusory sensation of ownership over a surrogate limb or whole body can be induced through specific forms of multisensory stimulation, such as synchronous visuotactile tapping on the hidden real and visible rubber hand in the rubber hand illusion. Such methods have been used to induce ownership over a manikin and a virtual body that substitute the real body, as seen from first-person perspective, through a head-mounted display. However, the perceptual and behavioral consequences of such transformed body ownership have hardly been explored. In Exp. 1, immersive virtual reality was used to embody 30 adults as a 4-y-old child (condition C), and as an adult body scaled to the same height as the child (condition A), experienced from the first-person perspective, and with virtual and real body movements synchronized. The result was a strong body-ownership illusion equally for C and A. Moreover there was an overestimation of the sizes of objects compared with a nonembodied baseline, which was significantly greater for C compared with A. An implicit association test showed that C resulted in significantly faster reaction times for the classification of self with child-like compared with adult-like attributes. Exp. 2 with an additional 16 participants extinguished the ownership illusion by using visuomotor asynchrony, with all else equal. The size-estimation and implicit association test differences between C and A were also extinguished. We conclude that there are perceptual and probably behavioral correlates of body-ownership illusions that occur as a function of the type of body in which embodiment occurs.

  2. Beauty, body size and wages: Evidence from a unique data set.

    PubMed

    Oreffice, Sonia; Quintana-Domeque, Climent

    2016-09-01

    We analyze how attractiveness rated at the start of the interview in the German General Social Survey is related to weight, height, and body mass index (BMI), separately by gender and accounting for interviewers' characteristics or fixed effects. We show that height, weight, and BMI all strongly contribute to male and female attractiveness when attractiveness is rated by opposite-sex interviewers, and that anthropometric characteristics are irrelevant to male interviewers when assessing male attractiveness. We also estimate whether, controlling for beauty, body size measures are related to hourly wages. We find that anthropometric attributes play a significant role in wage regressions in addition to attractiveness, showing that body size cannot be dismissed as a simple component of beauty. Our findings are robust to controlling for health status and accounting for selection into working.

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

    PubMed

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

    2015-11-01

    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.

  4. 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

  5. Biogeography and body size shuffling of aquatic salamander communities on a shifting refuge

    PubMed Central

    Bonett, Ronald M.; Trujano-Alvarez, Ana Lilia; Williams, Michael J.; Timpe, Elizabeth K.

    2013-01-01

    Freshwater habitats of coastal plains are refugia for many divergent vertebrate lineages, yet these environments are highly vulnerable to sea-level fluctuations, which suggest that resident communities have endured dynamic histories. Using the fossil record and a multi-locus nuclear phylogeny, we examine divergence times, biogeography, body size evolution and patterns of community assembly of aquatic salamanders from North American coastal plains since the Late Cretaceous. At least five salamander families occurred on the extensive Western Interior Coastal Plain (WICP), which existed from the Late Cretaceous through the Eocene. Four of these families subsequently colonized the emergent Southeastern Coastal Plain (SECP) by the Early Oligocene to Late Miocene. Three families ultimately survived and underwent extensive body size evolution in situ on the SECP. This included at least two major size reversals in recent taxa that are convergent with confamilial WICP ancestors. Dynamics of the coastal plain, major lineage extinctions and frequent extreme changes in body size have resulted in significant shuffling of the size structure of aquatic salamander communities on this shifting refuge since the Cretaceous. PMID:23466988

  6. Biogeography and body size shuffling of aquatic salamander communities on a shifting refuge.

    PubMed

    Bonett, Ronald M; Trujano-Alvarez, Ana Lilia; Williams, Michael J; Timpe, Elizabeth K

    2013-05-07

    Freshwater habitats of coastal plains are refugia for many divergent vertebrate lineages, yet these environments are highly vulnerable to sea-level fluctuations, which suggest that resident communities have endured dynamic histories. Using the fossil record and a multi-locus nuclear phylogeny, we examine divergence times, biogeography, body size evolution and patterns of community assembly of aquatic salamanders from North American coastal plains since the Late Cretaceous. At least five salamander families occurred on the extensive Western Interior Coastal Plain (WICP), which existed from the Late Cretaceous through the Eocene. Four of these families subsequently colonized the emergent Southeastern Coastal Plain (SECP) by the Early Oligocene to Late Miocene. Three families ultimately survived and underwent extensive body size evolution in situ on the SECP. This included at least two major size reversals in recent taxa that are convergent with confamilial WICP ancestors. Dynamics of the coastal plain, major lineage extinctions and frequent extreme changes in body size have resulted in significant shuffling of the size structure of aquatic salamander communities on this shifting refuge since the Cretaceous.

  7. Controls on body size during the Late Permian mass extinction event.

    PubMed

    He, W-H; Twitchett, R J; Zhang, Y; Shi, G R; Feng, Q-L; Yu, J-X; Wu, S-B; Peng, X-F

    2010-12-01

    This study examines the morphological responses of Late Permian brachiopods to environmental changes. Quantitative analysis of body size data from Permian-Triassic brachiopods has demonstrated significant, directional changes in body size before, during and after the Late Permian mass extinction event. Brachiopod size significantly reduced before and during the extinction interval, increased for a short time in more extinction-resistant taxa in the latter stages of extinction and then dramatically reduced again across the Permian/Triassic boundary. Relative abundances of trace elements and acritarchs demonstrate that the body size reductions which happened before, during and after extinction were driven by primary productivity collapse, whereas declining oxygen levels had less effect. An episode of size increase in two of the more extinction-resistant brachiopod species is unrelated to environmental change and possibly was the result of reduced interspecific competition for resources following the extinction of competitors. Based on the results of this study, predictions can be made for the possible responses of modern benthos to present-day environmental changes.

  8. Female mate preferences for male body size and shape promote sexual isolation in threespine sticklebacks

    PubMed Central

    Head, Megan L; Kozak, Genevieve M; Boughman, Janette W

    2013-01-01

    Female mate preferences for ecologically relevant traits may enhance natural selection, leading to rapid divergence. They may also forge a link between mate choice within species and sexual isolation between species. Here, we examine female mate preference for two ecologically important traits: body size and body shape. We measured female preferences within and between species of benthic, limnetic, and anadromous threespine sticklebacks (Gasterosteus aculeatus species complex). We found that mate preferences differed between species and between contexts (i.e., within vs. between species). Within species, anadromous females preferred males that were deep bodied for their size, benthic females preferred larger males (as measured by centroid size), and limnetic females preferred males that were more limnetic shaped. In heterospecific mating trials between benthics and limnetics, limnetic females continued to prefer males that were more limnetic like in shape when presented with benthic males. Benthic females showed no preferences for size when presented with limnetic males. These results show that females use ecologically relevant traits to select mates in all three species and that female preference has diverged between species. These results suggest that sexual selection may act in concert with natural selection on stickleback size and shape. Further, our results suggest that female preferences may track adaptation to local environments and contribute to sexual isolation between benthic and limnetic sticklebacks. PMID:23919161

  9. Subcutaneous Adipose Cell Size and Distribution: Relationship to Insulin Resistance and Body Fat

    PubMed Central

    McLaughlin, T; Lamendola, C; Coghlan, N; Liu, TC; Lerner, K; Sherman, A; Cushman, SW

    2015-01-01

    Metabolic heterogeneity among obese individuals may be attributable to differences in adipose cell size. We sought to clarify this by quantifying adipose cell-size distribution, body fat, and insulin-mediated glucose uptake in overweight/moderately-obese individuals. 148 healthy nondiabetic subjects with BMI 25–38 kg/m2 underwent subcutaneous adipose tissue biopsies and quantification of insulin-mediated glucose uptake with steady-state plasma glucose concentrations (SSPG) during the modified insulin suppression test. Cell-size distributions were obtained with Beckman Coulter Multisizer. Primary endpoints included % small adipose cells and diameter of large adipose cells. Cell-size and metabolic parameters were compared by regression for the whole group; according to IR and IS subgroups; and by body fat quintile. Both large and small adipose cells were present in nearly equal proportions. Percent small cells was associated with SSPG (r=0.26, p=0.003). Compared to BMI-matched IS individuals, IR counterparts demonstrated fewer, but larger large adipose cells, and a greater proportion of small-to-large adipose cells. Diameter of the large adipose cells was associated with %body fat (r=0.26, p=0.014), female sex (r=0.21, p=0.036), and SSPG (r=0.20, p=0.012). In the highest vs lowest % body fat quintile, adipose cell size increased by only 7% whereas adipose cell number increased by 74%. Recruitment of adipose cells is required for expansion of body fat mass beyond BMI of 25 kg/m2. Insulin resistance is associated with accumulation of small adipose cells and enlargement of large adipose cells. These data support the notion that impaired adipogenesis may underlie insulin resistance. PMID:23666871

  10. Interannual variability in stock abundance and body size of Pacific salmon in the central Bering Sea

    NASA Astrophysics Data System (ADS)

    Ishida, Y.; Azumaya, T.; Fukuwaka, M.; Davis, N.

    2002-10-01

    Variability in catch-per-unit-effort (CPUE) and mean body size was examined for pink, chum and sockeye salmon collected with research gillnets in the central Bering Sea in July from 1972 to 2000. The CPUEs for all three species showed significant increasing trends, but with large interannual variability. The CPUE of pink salmon was higher in odd years than in even years, and abruptly increased in the odd years post-1989. Chum salmon also showed odd/even year fluctuations, which were out-of-phase with those of pink salmon. Sockeye salmon showed no biennial such fluctuations. The CPUEs of chum and sockeye salmon were higher during 1979-1984 and 1992-1998, but lower during 1985-1991, especially for younger age group such as ocean age 2 and 3. Data for sea surface temperature (SST) and abundances of chum and sockeye salmon during four periods (1972-1976, 1977-1984, 1985-1990, and 1991-2000) indicated a portion of chum and sockeye salmon were distributed in the northern Gulf of Alaska in 1985-1990, when SST in the Gulf of Alaska was low. However, the fish were more abundant in the Bering Sea in 1977-1984 and 1991-2000 when SST was relatively high in the Gulf of Alaska. Body size of pink salmon showed a significant decreasing trend. Chum and sockeye salmon also showed significant decreasing trends in body size at ocean age 3 and older ages, but not at ocean age 2. Significant negati