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Sample records for affecting life history

  1. The odor of a plant metabolite affects life history traits in dietary restricted adult olive flies

    PubMed Central

    Gerofotis, Christos D.; Ioannou, Charalampos S.; Nakas, Christos T.; Papadopoulos, Nikos T.

    2016-01-01

    Food quality shapes life history traits either directly or through response of individuals to additional environmental factors, such as chemical cues. Plant extracts used as food additives modulate key life history traits; however little is known regarding such effects for olfactory chemical cues. Exploiting an interesting experimental system that involves the olive fly (Bactrocera oleae) and the plant metabolite α-pinene we asked whether exposure of adults to this compound modulates adult longevity and female reproduction in similar manner in a stressful – dietary (protein) restricted (DR) and in a relaxed- full diet (FD) feeding environment. Accordingly, we exposed males and females to the aroma of α-pinene and measured lifespan and age-specific fecundity in the above two dietary contexts. Our results demonstrate that exposure to α-pinene increased longevity in males and fecundity in females only under dietary restricted conditions. In relaxed food conditions, females exposed to α-pinene shifted high egg-laying towards younger ages compared to non-exposed ones. This is the first report demonstrating that a plant compound affects key life history traits of adult olive flies through olfaction. These effects are sex-specific and more pronounced in dietary restricted adults. Possible underlying mechanisms and the ecological significance are discussed. PMID:27339862

  2. Regional variation in seasonality affects migratory behaviour and life-history traits of two Mediterranean passerines

    NASA Astrophysics Data System (ADS)

    Pérez-Tris, Javier; Tellería, José Luis

    2002-03-01

    Migratory birds may improve fecundity by moving to seasonal breeding areas, but may also suffer higher mortality rates as a cost of movement. However, the covariation among seasonality, migratoriness and life histories should change between species if their ecological features affect site-tenacity, survival or fecundity. In frugivorous birds, for instance, wandering in search of fruits may trigger broader migrations than territorial defence, and also may improve nonbreeding survival by preventing food shortages that eventually happen in discrete territories. We studied the variation in spatio-temporal distribution, life expectancy and fecundity in robins ( Erithacus rubecula) and blackcaps ( Sylvia atricapilla) distributed in three Iberian regions with a low, mid or high degree of environmental seasonality. In the Iberian Peninsula, robins and blackcaps are the two most intensive frugivores in winter; however, robins are territorial while blackcaps track fruit abundance among habitat patches. In the most seasonal area, robins and blackcaps decreased abundance in winter and showed a lower breeding-site tenacity, a shorter life expectancy and a larger clutch size. However, blackcaps tended to be more migratory than robins in all regions. Despite their stronger migratory behaviour, blackcaps showed a longer life expectancy and a smaller clutch size than robins in all regions. In robins, winter territoriality could decrease nonbreeding survival but also improve fecundity, because survivors are dominant and hence more efficient breeders. In blackcaps, however, the use of the most profitable habitat patches could improve nonbreeding survival, thereby allowing a similar recruitment than in robins with a lower reproductive investment. These results support that regional-scale changes in seasonality may affect migratory behaviour and hence the tradeoff between reproduction and survival in birds, doing so differently depending on the idiosyncrasy of each species.

  3. Larval nutritional stress affects vector life history traits and human malaria transmission

    PubMed Central

    Vantaux, Amélie; Lefèvre, Thierry; Cohuet, Anna; Dabiré, Kounbobr Roch; Roche, Benjamin; Roux, Olivier

    2016-01-01

    Exposure to stress during an insect’s larval development can have carry-over effects on adult life history traits and susceptibility to pathogens. We investigated the effects of larval nutritional stress for the first time using field mosquito vectors and malaria parasites. In contrast to previous studies, we show that larval nutritional stress may affect human to mosquito transmission antagonistically: nutritionally deprived larvae showed lower parasite prevalence for only one gametocyte carrier; they also had lower fecundity. However, they had greater survival rates that were even higher when infected. When combining these opposing effects into epidemiological models, we show that larval nutritional stress induced a decrease in malaria transmission at low mosquito densities and an increase in transmission at high mosquito densities, whereas transmission by mosquitoes from well-fed larvae was stable. Our work underscores the importance of including environmental stressors towards understanding host–parasite dynamics to improve disease transmission models and control. PMID:27827429

  4. Larval nutritional stress affects vector life history traits and human malaria transmission.

    PubMed

    Vantaux, Amélie; Lefèvre, Thierry; Cohuet, Anna; Dabiré, Kounbobr Roch; Roche, Benjamin; Roux, Olivier

    2016-11-09

    Exposure to stress during an insect's larval development can have carry-over effects on adult life history traits and susceptibility to pathogens. We investigated the effects of larval nutritional stress for the first time using field mosquito vectors and malaria parasites. In contrast to previous studies, we show that larval nutritional stress may affect human to mosquito transmission antagonistically: nutritionally deprived larvae showed lower parasite prevalence for only one gametocyte carrier; they also had lower fecundity. However, they had greater survival rates that were even higher when infected. When combining these opposing effects into epidemiological models, we show that larval nutritional stress induced a decrease in malaria transmission at low mosquito densities and an increase in transmission at high mosquito densities, whereas transmission by mosquitoes from well-fed larvae was stable. Our work underscores the importance of including environmental stressors towards understanding host-parasite dynamics to improve disease transmission models and control.

  5. Association with pathogenic bacteria affects life-history traits and population growth in Caenorhabditis elegans.

    PubMed

    Diaz, S Anaid; Mooring, Eric Q; Rens, Elisabeth G; Restif, Olivier

    2015-04-01

    Determining the relationship between individual life-history traits and population dynamics is an essential step to understand and predict natural selection. Model organisms that can be conveniently studied experimentally at both levels are invaluable to test the rich body of theoretical literature in this area. The nematode Caenorhabditis elegans, despite being a well-established workhorse in genetics, has only recently received attention from ecologists and evolutionary biologists, especially with respect to its association with pathogenic bacteria. In order to start filling the gap between the two areas, we conducted a series of experiments aiming at measuring life-history traits as well as population growth of C. elegans in response to three different bacterial strains: Escherichia coli OP50, Salmonella enterica Typhimurium, and Pseudomonas aeruginosa PAO1. Whereas previous studies had established that the latter two reduced the survival of nematodes feeding on them compared to E. coli OP50, we report for the first time an enhancement in reproductive success and population growth for worms feeding on S. enterica Typhimurium. Furthermore, we used an age-specific population dynamic model, parameterized using individual life-history assays, to successfully predict the growth of populations over three generations. This study paves the way for more detailed and quantitative experimental investigation of the ecology and evolution of C. elegans and the bacteria it interacts with, which could improve our understanding of the fate of opportunistic pathogens in the environment.

  6. Life-history data.

    PubMed

    Vanhoutte, Bram; Nazroo, James

    2016-07-15

    Life-history data are quantitative, retrospective and autobiographical data collected through event-history calendars. By mimicking the structure of our memories, these instruments can gather reliable information on different dimensions of the lifecourse. Life-history data enable the duration, timing and ordering of events to be brought to the foreground of analysis. Extending the scope of lifecourse research, life-history data make it possible to examine the long-term effects of past policies with more precision and detail.

  7. Larval nutrition affects life history traits in a capital breeding moth.

    PubMed

    Colasurdo, Nadia; Gélinas, Yves; Despland, Emma

    2009-06-01

    Fitness depends not only on resource uptake but also on the allocation of these resources to various life history functions. This study explores the life-history consequences of larval diet in terms not only of larval performance but also of adult body composition and reproductive traits in the forest tent caterpillar (Malacosoma disstria Hübner). Caterpillars were reared on their preferred tree host, trembling aspen (Populus tremuloides), or on one of three artificial foods: high protein:low carbohydrate, equal protein-to-carbohydrate ratio or low protein:high carbohydrate. Survivorship, larval development rate and adult body size were lowest on the carbohydrate-biased diet and similar on the protein-biased and equal-ratio diets. Fecundity increased with body size but did not otherwise differ between diets. Moths reared on the carbohydrate-biased diet allocated a lower proportion of their mass to the ovaries and more to somatic growth whereas those on equal-ratio and protein-biased diets allocated more to reproductive tissue and less to somatic tissue. These differences in allocation to reproduction arose from differences in the size of eggs, an index of offspring quality. No differences were found in lipid and protein content of female ovaries, accessory glands or somatic tissue, or of the whole body of male moths. The findings show that physiological processes regulate the composition of the different components of the adult body. Diet effects occur as differences in overall body size and in relative allocation to these components. Although lepidopterans can, to a large extent, compensate post-ingestively for nutritionally deficient diets, investment in reproduction vs somatic growth depends on the nutrients available.

  8. Why does offspring size affect performance? Integrating metabolic scaling with life-history theory

    PubMed Central

    Pettersen, Amanda K.; White, Craig R.; Marshall, Dustin J.

    2015-01-01

    Within species, larger offspring typically outperform smaller offspring. While the relationship between offspring size and performance is ubiquitous, the cause of this relationship remains elusive. By linking metabolic and life-history theory, we provide a general explanation for why larger offspring perform better than smaller offspring. Using high-throughput respirometry arrays, we link metabolic rate to offspring size in two species of marine bryozoan. We found that metabolism scales allometrically with offspring size in both species: while larger offspring use absolutely more energy than smaller offspring, larger offspring use proportionally less of their maternally derived energy throughout the dependent, non-feeding phase. The increased metabolic efficiency of larger offspring while dependent on maternal investment may explain offspring size effects—larger offspring reach nutritional independence (feed for themselves) with a higher proportion of energy relative to structure than smaller offspring. These findings offer a potentially universal explanation for why larger offspring tend to perform better than smaller offspring but studies on other taxa are needed. PMID:26559952

  9. Colony pace: a life-history trait affecting social insect epidemiology

    PubMed Central

    Buechel, Séverine Denise; Schmid-Hempel, Paul

    2016-01-01

    Among colonies of social insects, the worker turnover rate (colony ‘pace’) typically shows considerable variation. This has epidemiological consequences for parasites, because in ‘fast-paced’ colonies, with short-lived workers, the time of parasite residence in a given host will be reduced, and further transmission may thus get less likely. Here, we test this idea and ask whether pace is a life-history strategy against infectious parasites. We infected bumblebees (Bombus terrestris) with the infectious gut parasite Crithidia bombi, and experimentally manipulated birth and death rates to mimic slow and fast pace. We found that fewer workers and, importantly, fewer last-generation workers that are responsible for rearing sexuals were infected in colonies with faster pace. This translates into increased fitness in fast-paced colonies, as daughter queens exposed to fewer infected workers in the nest are less likely to become infected themselves, and have a higher chance of founding their own colonies in the next year. High worker turnover rate can thus act as a strategy of defence against a spreading infection in social insect colonies. PMID:26763696

  10. Life history affects how species experience succession in pen shell metacommunities.

    PubMed

    Munguia, Pablo

    2014-04-01

    In nature, very few species are common and broadly distributed. Most species are rare and occupy few sites; this pattern is ubiquitous across habitats and taxa. In spatially structured communities (metacommunities), regional distribution and local abundance may change as the relative effects of within-habitat processes (e.g., species interactions) and among-habitat processes (e.g., dispersal) may vary through succession. A field experiment with the marine benthic inhabitants of pen shells (Atrina rigida) tested how common and rare species respond to succession and metacommunity size. I followed community development through time and partitioned species into sessile and motile based on their natural history. Rare species drive diversity patterns and are influenced by metacommunity size: there are strong abundance-distribution differences between common and rare species in large metacommunities, but motile species show lower rates of change than sessile species. In small metacommunities both common and rare species have similar changes through time; the dichotomous distinction of common and rare species is not present. Edge effects in metacommunities affect species' changes in distribution and abundance. In large metacommunities diversity is higher in edge habitats relative to small metacommunities during early succession. However, edge effects benefit motile species over time in small metacommunities showing a rapid increase in diversity. Individual mobility is sensitive to regional community size and allows individuals to sort among different communities. In contrast, sessile species do not show this edge effect. Metacommunity theory is a useful framework for understanding spatially structured communities, but the natural history of coexisting species cannot be ignored.

  11. Wheat cultivars affecting life history and digestive amylolytic activity of Sitotroga cerealella Olivier (Lepidoptera: Gelechiidae).

    PubMed

    Borzoui, E; Naseri, B

    2016-08-01

    The life history and digestive α-amylase activity of the Angoumois grain moth, Sitotroga cerealella Olivier (Lepidoptera: Gelechiidae) were studied on six wheat cultivars (Arg, Bam, Nai 60, Pishtaz, Sepahan and Shanghai) at 25 ± 1°C, relative humidity of 65 ± 5% and a photoperiod of 16:8 (L:D) h. A delay in the developmental time of S. cerealella immature stages was detected when larvae were fed on cultivar Sepahan. The maximum survival rate of immature stages was seen on cultivar Bam (93.33 ± 2.10%), and the minimum rates were on cultivars Nai 60 (54.66 ± 2.49%) and Sepahan (49.33 ± 4.52%). The highest realized fecundity and fertility were recorded for females which came from larvae fed on cultivar Bam (93.30 ± 2.10 eggs/female and 91.90 ± 3.10%, respectively); and the lowest ones were observed for females which came from larvae fed on cultivar Sepahan (49.30 ± 4.50 eggs/female and 67.4 ± 11.1%, respectively). The heaviest male and female weights of S. cerealella were observed on cultivar Bam (2.97 ± 0.02 and 4.80 ± 0.01 mg, respectively). The highest amylolytic activity of the fourth instar was detected on cultivar Bam (0.89 ± 0.04 mg maltose min-1), which had the maximum mean hundred-wheat weight (5.92 ± 0.19 g). One α-amylase isozyme was detected in the midgut extracts from the fourth instar larvae fed on different wheat cultivars, and the highest intensity was found in larvae fed on cultivar Bam. Correlation analyses showed that very high correlations existed between the immature period, fecundity and fertility on one side and inhibition of α-amylase, soluble starch content and hundred-wheat weight on the other. According to the obtained results, cultivar Sepahan is an unfavorable host for the feeding and development of S. cerealella.

  12. Reciprocity in predator-prey interactions: exposure to defended prey and predation risk affects intermediate predator life history and morphology.

    PubMed

    Hammill, Edd; Beckerman, Andrew P

    2010-05-01

    A vast body of literature exists documenting the morphological, behavioural and life history changes that predators induce in prey. However, little attention has been paid to how these induced changes feed back and affect the predators' life history and morphology. Larvae of the phantom midge Chaoborus flavicans are intermediate predators in a food web with Daphnia pulex as the basal resource and planktivorous fish as the top predator. C. flavicans prey on D. pulex and are themselves prey for fish; as D. pulex induce morphological defences in the presence of C. flavicans this is an ideal system in which to evaluate the effects of defended prey and top predators on an intermediate consumer. We assessed the impact on C. flavicans life history and morphology of foraging on defended prey while also being exposed to the non-lethal presence of a top fish predator. We tested the basic hypothesis that the effects of defended prey will depend on the presence or absence of top predator predation risk. Feeding rate was significantly reduced and time to pupation was significantly increased by defended morph prey. Gut size, development time, fecundity, egg size and reproductive effort respond to fish chemical cues directly or significantly alter the relationship between a trait and body size. We found no significant interactions between prey morph and the non-lethal presence of a top predator, suggesting that the effects of these two biological factors were additive or singularly independent. Overall it appears that C. flavicans is able to substantially modify several aspects of its biology, and while some changes appear mere consequences of resource limitation others appear facultative in nature.

  13. Demography, disease and the devil: life-history changes in a disease-affected population of Tasmanian devils (Sarcophilus harrisii).

    PubMed

    Lachish, Shelly; McCallum, Hamish; Jones, Menna

    2009-03-01

    1. Examining the demographic responses of populations to disease epidemics and the nature of compensatory responses to perturbation from epidemics is critical to our understanding of the processes affecting population dynamics and our ability to conserve threatened species. Such knowledge is currently available for few systems. 2. We examined changes to the demography and life-history traits of a population of Tasmanian devils (Sarcophilus harrisii) following the arrival of a debilitating infectious disease, devil facial tumour disease (DFTD), and investigated the population's ability to compensate for the severe population perturbation caused by this epizootic. 3. There was a significant change to the age structure following the arrival of DFTD to the Freycinet Peninsula. This shift to a younger population was caused by the loss of older individuals from the population as a direct consequence of DFTD-driven declines in adult survival rates. 4. Offspring sex ratios of disease mothers were more female biased than those of healthy mothers, indicating that devils may facultatively adjust offspring sex ratios in response to disease-induced changes in maternal condition. 5. We detected evidence of reproductive compensation in response to disease impacts via a reduction in the age of sexual maturity of females (an increase in precocial breeding) over time. 6. The strength of this compensatory response appeared to be limited by factors that constrain the ability of individuals to reach a critical size for sexual maturity in their first year, because of the time limit dictated by the annual breeding season. 7. The ongoing devastating impacts of this disease for adult survival and the apparent reliance of precocial breeding on rapid early growth provide the opportunity for evolution to favour of this new life-history pattern, highlighting the potential for novel infectious diseases to be strong selective forces on life-history evolution.

  14. Life history analysis of HIV/AIDS-affected households in rice and cassava-based farming communities in Northern Malawi.

    PubMed

    Yajima, Midori; van Huis, Arnold; Jiggins, Janice

    2010-10-01

    The "New Variant Famine" hypothesis proposed that AIDS offers a major challenge to food security in this part of Africa by impairing the functioning of traditional support systems, leading to the collapse of "social immunity". This study explores the changing perceptions of HIV and AIDS and peoples' responses to its impact by eliciting life history narratives of 30 respondents in Northern Malawi. We classified respondents by means of gender, livelihood systems and AIDS impact levels. Respondents reported a range of critical events, recorded in the life histories, that threatened their "social immunity", including deaths, sicknesses, migration, marriages and divorces, and dropping out of school; i.e., a greater range of risks than AIDS alone, that need to be recognised in HIV and AIDS programming. For the respondents who were classified as "AIDS-affected", learning about their seropositive status was found to be an important, and in some cases a positive, turning point in their lives in terms of behavioural changes, such as joining support groups and opening up to discussion of the implications of their status. The emerging social organisations could re-create social capacity and check the downward spiral proposed by the "New Variant Famine" hypothesis. To promote this shift and to confer a higher level of "social immunity", investments in expanding access to voluntary counselling and testing and antiretroviral therapy services, and assistance to community-based organisations would be essential.

  15. Food concentration affects the life history response of Ceriodaphnia cf. dubia to chemicals with different mechanisms of action.

    PubMed

    Rose, R M; Warne, M St J; Lim, R P

    2002-02-01

    The effect of three chemicals with different mechanisms of action (3,4-dichloroaniline, fenoxycarb, and chlorpyrifos) on the life history response of the cladoceran Ceriodaphnia cf. dubia was examined under both limited (3 x 10(4) cells/mL) and abundant (15 x 10(4) cells/mL) food conditions. Toxicity tests were conducted at both food concentrations simultaneously for each chemical, and cladocerans were examined daily from less than 24 h old until their death. A range of life history parameters were calculated, including mean brood sizes, survival, net reproductive rate, and population growth rate. The toxicity of 3,4-dichloroaniline was not significantly affected by food concentration. However, limited food significantly decreased the toxicity of fenoxycarb, and significantly increased the toxicity of chlorpyrifos. The effect of food concentration on toxicity appears to depend on the mechanism by which the chemical exerts its toxicity and on food--chemical interactions. Possible mechanisms for the different effects of food concentration on toxicity are discussed.

  16. Inducible offences affect predator-prey interactions and life-history plasticity in both predators and prey.

    PubMed

    Kishida, Osamu; Costa, Zacharia; Tezuka, Ayumi; Michimae, Hirofumi

    2014-07-01

    Phenotypic plasticity can have strong impacts on predator-prey interactions. Although much work has examined the effects of inducible defences, less understood is how inducible offences in predators affect predator-prey interactions and predator and prey phenotypes. Here, we examine the impacts of an inducible offence on the interactions and life histories of a cohort of predatory Hynobius retardatus salamander larvae and their prey, Rana pirica tadpoles. We examined larval (duration, survival) and post-metamorphic (size) traits of both species after manipulating the presence/absence of tadpoles and salamanders with offensive (broadened gape width) or non-offensive phenotypes in pond enclosures. Offensive phenotype salamanders reduced tadpole survival and metamorph emergence by 58% compared to tadpole-only treatments, and by over 30% compared to non-offensive phenotypes. Average time to metamorphosis of frogs was delayed by 30% in the presence of salamanders, although this was independent of salamander phenotype. Thus, offensive phenotype salamanders reduced the number of tadpoles remaining in the pond over time by reducing tadpole survival, not by altering patterns of metamorph emergence. Offensive phenotypes also caused tadpoles to metamorphose 19% larger than no salamander treatments and 6% larger than non-offensive phenotype treatments. Pooled across salamander treatments, tadpoles caused salamanders to reach metamorphosis faster and larger. Moreover, in the presence of tadpoles, offensive phenotype salamanders metamorphosed 25% faster and 5% larger than non-offensive phenotype salamanders, but in their absence, neither their size nor larval period differed from non-offensive phenotype individuals. To our knowledge, this study is the first to demonstrate that inducible offences in predators can have strong impacts on predator and prey phenotypes across multiple life stages. Since early metamorphosis at a larger size has potential fitness advantages, the impacts

  17. Interspecies systems biology uncovers metabolites affecting C. elegans gene expression and life history traits.

    PubMed

    Watson, Emma; MacNeil, Lesley T; Ritter, Ashlyn D; Yilmaz, L Safak; Rosebrock, Adam P; Caudy, Amy A; Walhout, Albertha J M

    2014-02-13

    Diet greatly influences gene expression and physiology. In mammals, elucidating the effects and mechanisms of individual nutrients is challenging due to the complexity of both the animal and its diet. Here, we used an interspecies systems biology approach with Caenorhabditis elegans and two of its bacterial diets, Escherichia coli and Comamonas aquatica, to identify metabolites that affect the animal's gene expression and physiology. We identify vitamin B12 as the major dilutable metabolite provided by Comamonas aq. that regulates gene expression, accelerates development, and reduces fertility but does not affect lifespan. We find that vitamin B12 has a dual role in the animal: it affects development and fertility via the methionine/S-Adenosylmethionine (SAM) cycle and breaks down the short-chain fatty acid propionic acid, preventing its toxic buildup. Our interspecies systems biology approach provides a paradigm for understanding complex interactions between diet and physiology.

  18. Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history.

    PubMed

    Cunningham, Susan J; Kruger, Andries C; Nxumalo, Mthobisi P; Hockey, Philip A R

    2013-01-01

    Increases in the frequency, duration and intensity of heat waves are frequently evoked in climate change predictions. However, there is no universal definition of a heat wave. Recent, intense hot weather events have caused mass mortalities of birds, bats and even humans, making the definition and prediction of heat wave events that have the potential to impact populations of different species an urgent priority. One possible technique for defining biologically meaningful heat waves is to use threshold temperatures (T(thresh)) above which known fitness costs are incurred by species of interest. We set out to test the utility of this technique using T(thresh) values that, when exceeded, affect aspects of the fitness of two focal southern African bird species: the southern pied babbler Turdiodes bicolor (T(thresh) = 35.5 °C) and the common fiscal Lanius collaris (T(thresh) = 33 °C). We used these T(thresh) values to analyse trends in the frequency, duration and intensity of heat waves of magnitude relevant to the focal species, as well as the annual number of hot days (maximum air temperature > T(thresh)), in north-western South Africa between 1961 and 2010. Using this technique, we were able to show that, while all heat wave indices increased during the study period, most rapid increases for both species were in the annual number of hot days and in the maximum intensity (and therefore intensity variance) of biologically meaningful heat waves. Importantly, we also showed that warming trends were not uniform across the study area and that geographical patterns in warming allowed both areas of high risk and potential climate refugia to be identified. We discuss the implications of the trends we found for our focal species, and the utility of the T(thresh) technique as a conservation tool.

  19. Life History and Identity

    ERIC Educational Resources Information Center

    Tierney, William G.

    2013-01-01

    This article uses the life history method to chronicle the challenges of a low-income, first-generation student en route to college. The paper addresses three questions: how Manuel navigates college and related topics such as roommates, family, and money; how he creates social networks; and how he works with adults such as teachers and…

  20. Perceived Risk of Predation Affects Reproductive Life-History Traits in Gambusia holbrooki, but Not in Heterandria formosa

    PubMed Central

    Mukherjee, Shomen; Heithaus, Michael R.; Trexler, Joel C.; Ray-Mukherjee, Jayanti; Vaudo, Jeremy

    2014-01-01

    Key to predicting impacts of predation is understanding the mechanisms through which predators impact prey populations. While consumptive effects are well-known, non-consumptive predator effects (risk effects) are increasingly being recognized as important. Studies of risk effects, however, have focused largely on how trade-offs between food and safety affect fitness. Less documented, and appreciated, is the potential for predator presence to directly suppress prey reproduction and affect life-history characteristics. For the first time, we tested the effects of visual predator cues on reproduction of two prey species with different reproductive modes, lecithotrophy (i.e. embryonic development primarily fueled by yolk) and matrotrophy (i.e. energy for embryonic development directly supplied by the mother to the embryo through a vascular connection). Predation risk suppressed reproduction in the lecithotrophic prey (Gambusia holbrokii) but not the matrotroph (Heterandria formosa). Predator stress caused G. holbrooki to reduce clutch size by 43%, and to produce larger and heavier offspring compared to control females. H. formosa, however, did not show any such difference. In G. holbrooki we also found a significantly high percentage (14%) of stillbirths in predator-exposed treatments compared to controls (2%). To the best of our knowledge, this is the first direct empirical evidence of predation stress affecting stillbirths in prey. Our results suggest that matrotrophy, superfetation (clutch overlap), or both decrease the sensitivity of mothers to environmental fluctuation in resource (food) and stress (predation risk) levels compared to lecithotrophy. These mechanisms should be considered both when modeling consequences of perceived risk of predation on prey-predator population dynamics and when seeking to understand the evolution of reproductive modes. PMID:24551171

  1. Perceived risk of predation affects reproductive life-history traits in Gambusia holbrooki, but not in Heterandria formosa.

    PubMed

    Mukherjee, Shomen; Heithaus, Michael R; Trexler, Joel C; Ray-Mukherjee, Jayanti; Vaudo, Jeremy

    2014-01-01

    Key to predicting impacts of predation is understanding the mechanisms through which predators impact prey populations. While consumptive effects are well-known, non-consumptive predator effects (risk effects) are increasingly being recognized as important. Studies of risk effects, however, have focused largely on how trade-offs between food and safety affect fitness. Less documented, and appreciated, is the potential for predator presence to directly suppress prey reproduction and affect life-history characteristics. For the first time, we tested the effects of visual predator cues on reproduction of two prey species with different reproductive modes, lecithotrophy (i.e. embryonic development primarily fueled by yolk) and matrotrophy (i.e. energy for embryonic development directly supplied by the mother to the embryo through a vascular connection). Predation risk suppressed reproduction in the lecithotrophic prey (Gambusia holbrokii) but not the matrotroph (Heterandria formosa). Predator stress caused G. holbrooki to reduce clutch size by 43%, and to produce larger and heavier offspring compared to control females. H. formosa, however, did not show any such difference. In G. holbrooki we also found a significantly high percentage (14%) of stillbirths in predator-exposed treatments compared to controls (2%). To the best of our knowledge, this is the first direct empirical evidence of predation stress affecting stillbirths in prey. Our results suggest that matrotrophy, superfetation (clutch overlap), or both decrease the sensitivity of mothers to environmental fluctuation in resource (food) and stress (predation risk) levels compared to lecithotrophy. These mechanisms should be considered both when modeling consequences of perceived risk of predation on prey-predator population dynamics and when seeking to understand the evolution of reproductive modes.

  2. Stress and life history.

    PubMed

    Monaghan, Pat; Spencer, Karen A

    2014-05-19

    In his book on behavioural endocrinology, Randy Nelson describes 'stress' as a 'notoriously ethereal concept'. Yet, despite this lack of clarity, studies of the consequences of stress across different time scales, life history stages, taxa and levels of biological enquiry form a large part of modern biology and biomedicine. Organisms need to recognise and respond to environmental challenges. Being able to do so appropriately, and with minimal costs, is an important physiological attribute, with great adaptive value. The costs and benefits of different mechanisms that enable organisms to cope with unpredictable environmental changes can be manifest to different degrees at different life stages. Accordingly, the level of stress experienced in the environment can act as a strong selective pressure that drives the evolution of life histories.

  3. Exposure of leopard frogs to a pesticide mixture affects life history characteristics of the lungworm Rhabdias ranae.

    PubMed

    Gendron, A D; Marcogliese, D J; Barbeau, S; Christin, M-S; Brousseau, P; Ruby, S; Cyr, D; Fournier, M

    2003-05-01

    We tested the hypothesis that exposure of leopard frogs ( Rana pipiens) to agricultural pesticides can affect the infection dynamics of a common parasite of ranid frogs, the lungworm Rhabdias ranae. After a 21-day exposure to sublethal concentrations of a pesticide mixture composed of atrazine, metribuzin, aldicarb, endosulfan, lindane and dieldrin, or to control solutions (water, dimethyl sulfoxide), parasite-free juvenile frogs were challenged with 30 infective larvae of R. ranae. Approximately 75% of the larvae penetrated the skin and survived in both exposed and control animals, suggesting that pesticides did not influence host recognition or penetration components of the transmission process. Rather, we found that the migration of R. ranae was significantly accelerated in hosts exposed to the highest concentrations of pesticides, leading to the establishment of twice as many adult worms in the lungs of frogs 21 days post-infection. Pesticide treatment did not influence the growth of lungworms but our results indicate that they matured and reproduced earlier in pesticide-exposed frogs compared to control animals. Such alterations in life history characteristics that enhance parasite transmission may lead to an increase in virulence. Supporting evidence shows that certain components of the frog immune response were significantly suppressed after exposure to the pesticide mixture. This suggests that the immune system of anurans exerts a control over lungworm migration and maturation and that agricultural contaminants can interfere with these control mechanisms. Our results also contribute to the ongoing debate regarding the role that anthropogenic factors could play in the perplexing disease-related die-offs of amphibians observed in several parts of the world.

  4. Zebra mussel life history

    SciTech Connect

    Ackerman, J.D.

    1995-06-01

    The success of introduced zebra mussels (Dreissena polymorpha (Pallas) and Dreissena bugensis Andrusova) can be related in large parttot a life history that is unlike that of the indigenous freshwater fauna and yet is conserved with marine bivalves. Following external fertilization and embryological development, there is a brief trochophore stage. With the development of a velum and the secretion of a D-shaped larval shell, the larva becomes a D-shaped veliger, which is the first recognizable planktonic larva. Later, the secretion of a second larval shell leads to the last obligate free-swimming veliger stage known as the veliconcha. The last larval stage known as the pediveliger, however, can both swim using its velum or crawl using its fully-functional foot. Pediveligers actively select substrates on which they {open_quotes}settle{close_quotes} by secreting byssal threads and undergo metamorphosis to become plantigrade mussels. The secretion of the adult shell and concomitant changes in growth axis leads to the heteromyariant or mussel-like shape, which is convergent with marine mussels. Like a number of other bivalves, zebra mussels produce byssal threads as adults, but these attachments may be broken enabling their translocation to new areas. The recognition and examination of these life history traits will lead to a better understanding of zebra mussel biology.

  5. Experience and Life History. Roskilde University Life History Project Paper.

    ERIC Educational Resources Information Center

    Salling Olesen, Henning

    The Life History Project at Denmark's Roskilde University is a 5-year research project that was initiated in 1998 to examine learning and participation in adult and continuing education from a life history perspective. The project was designed to build on a broad range of qualitative interview studies and case studies into learning processes. The…

  6. Germination season and watering regime, but not seed morph, affect life history traits in a cold desert diaspore-heteromorphic annual.

    PubMed

    Lu, Juan J; Tan, Dun Y; Baskin, Jerry M; Baskin, Carol C

    2014-01-01

    Seed morph, abiotic conditions and time of germination can affect plant fitness, but few studies have tested their combined effects on plasticity of plant life history traits. Thus, we tested the hypothesis that seed morph, germination season and watering regime influence phenotypic expression of post-germination life history traits in the diaspore-heteromorphic cold desert winter annual/spring ephemeral Diptychocarpus strictus. The two seed morphs were sown in watered and non-watered plots in late summer, and plants derived from them were watered or not-watered throughout the study. Seed morph did not affect phenology, growth and morphology, survival, dry mass accumulation and allocation or silique and seed production. Seeds in watered plots germinated in autumn (AW) and spring (SW) but only in spring for non-watered plots (SNW). A high percentage of AW, SW and SNW plants survived and reproduced, but flowering date and flowering period of autumn- vs. spring-germinated plants differed. Dry mass also differed with germination season/watering regime (AW > SW > SNW). Number of siliques and seeds increased with plant size (AW > SW > SNW), whereas percent dry mass allocated to reproduction was higher in small plants: SNW > SW > AW. Thus, although seed morph did not affect the expression of life history traits, germination season and watering regime significantly affected phenology, plant size and accumulation and allocation of biomass to reproduction. Flexibility throughout the life cycle of D. strictus is an adaptation to the variation in timing and amount of rainfall in its cold desert habitat.

  7. Temperature, activity, and lizard life histories.

    PubMed

    Adolph, S C; Porter, W P

    1993-08-01

    Lizard life-history characteristics vary widely among species and populations. Most authors seek adaptive or phylogenetic explanations for life-history patterns, which are usually presumed to reflect genetic differences. However, lizard life histories are often phenotypically plastic, varying in response to temperature, food availability, and other environmental factors. Despite the importance of temperature to lizard ecology and physiology, its effects on life histories have received relatively little attention. We present a theoretical model predicting the proximate consequences of the thermal environment for lizard life histories. Temperature, by affecting activity times, can cause variation in annual survival rate and fecundity, leading to a negative correlation between survival rate and fecundity among populations in different thermal environments. Thus, physiological and evolutionary models predict the same qualitative pattern of life-history variation in lizards. We tested our model with published life-history data from field studies of the lizard Sceloporus undulatus, using climate and geographical data to reconstruct estimated annual activity seasons. Among populations, annual activity times were negatively correlated with annual survival rate and positively correlated with annual fecundity. Proximate effects of temperature may confound comparative analyses of lizard life-history variation and should be included in future evolutionary models.

  8. Temperature, activity, and lizard life histories

    SciTech Connect

    Adolph, S.C.; Porter, W.P. )

    1993-08-01

    Lizard life-history characteristics vary widely among species and populations. Most authors seek adaptive or phylogenetic explanations for life-history patterns, which are usually presumed to reflect genetic differences. However, lizard life histories are often phenotypically plastic, varying in response to temperature, food availability, and other environmental factors. Despite the importance of temperature to lizard ecology and physiology, its effects on life histories have received relatively little attention. The authors present a theoretical model predicting the proximate consequences of the thermal environment for lizard life histories. Temperature, by affecting activity times, can cause variation in annual survival rate and fecundity, leading to a negative correlation between survival rate and fecundity among populations in different thermal environments. Thus, physiological and evolutionary models predict the same qualitative pattern of life-history variation in lizards. They tested their model with published life-history data from field studies of the lizard Sceloporus undulatus, using climate and geographical data to reconstruct estimated annual activity seasons. Among populations, annual activity times were negatively correlated with annual survival rate and positively correlated with annual fecundity. Proximate effects of temperature may confound comparative analyses of lizard life-history variation and should be included in future evolutionary models. 125 refs., 6 figs., 1 tab.

  9. Population momentum across vertebrate life histories

    USGS Publications Warehouse

    Koons, D.N.; Grand, J.B.; Arnold, J.M.

    2006-01-01

    Population abundance is critically important in conservation, management, and demographic theory. Thus, to better understand how perturbations to the life history affect long-term population size, we examined population momentum for four vertebrate classes with different life history strategies. In a series of demographic experiments we show that population momentum generally has a larger effect on long-term population size for organisms with long generation times than for organisms with short generation times. However, patterns between population momentum and generation time varied across taxonomic groups and according to the life history parameter that was changed. Our findings indicate that momentum may be an especially important aspect of population dynamics for long-lived vertebrates, and deserves greater attention in life history studies. Further, we discuss the importance of population momentum in natural resource management, pest control, and conservation arenas. ?? 2006 Elsevier B.V. All rights reserved.

  10. Tradeoffs in bacteriophage life histories.

    PubMed

    Keen, Eric C

    2014-01-01

    Viruses are the most abundant biological entities on the planet, yet most classical principles of evolutionary biology and ecology were not developed with viruses in mind. Here, the concept of biological tradeoffs, a fundamental tenet of life history theory, is examined in the context of bacteriophage biology. Specifically, several important parameters of phage life histories-replication, persistence, host range, and adsorption-are evaluated for tradeoffs. Available data indicate that replication rate is strongly negatively correlated with both persistence and host range, suggesting that the well-documented tradeoff in macroorganisms between offspring production and offspring quality also applies to phages. The biological tradeoffs that appear to characterize viruses' life histories have potential importance for viral evolution, ecology, and pathogenesis.

  11. Inconstant sun: how solar evolution has affected cosmic and ultraviolet radiation exposure over the history of life on Earth.

    PubMed

    Karam, P Andrew

    2003-03-01

    Four billion years ago, sea-level UV exposure was more than 400 times as intense as today, the dose from solar cosmic rays was five times present levels, and galactic cosmic rays accounted for only about 10% their current contribution to sea-level radiation doses. Exposure to cosmic radiation accounts for about 10% of natural background radiation exposure today and includes dose from galactic cosmic rays and solar charged particles. There is little exposure to ionizing wavelengths of UV due to absorption by ozone. The sun has evolved significantly over its life; in the past there were higher levels of particulate radiation and lower UV emissions from the sun, and a stronger solar wind reduced radiation dose in the inner solar system from galactic cosmic rays. Finally, since the early atmosphere contained little to no oxygen, surface levels of UV radiation were far higher in the past.

  12. Development on drought-stressed host plants affects life history, flight morphology and reproductive output relative to landscape structure.

    PubMed

    Gibbs, Melanie; Van Dyck, Hans; Breuker, Casper J

    2012-01-01

    With global climate change, rainfall is becoming more variable. Predicting the responses of species to changing rainfall levels is difficult because, for example in herbivorous species, these effects may be mediated indirectly through changes in host plant quality. Furthermore, species responses may result from a simultaneous interaction between rainfall levels and other environmental variables such as anthropogenic land use or habitat quality. In this eco-evolutionary study, we examined how male and female Pararge aegeria (L.) from woodland and agricultural landscape populations were affected by the development on drought-stressed host plants. Compared with individuals from woodland landscapes, when reared on drought-stressed plants agricultural individuals had longer development times, reduced survival rates and lower adult body masses. Across both landscape types, growth on drought-stressed plants resulted in males and females with low forewing aspect ratios and in females with lower wing loading and reduced fecundity. Development on drought-stressed plants also had a landscape-specific effect on reproductive output; agricultural females laid eggs that had a significantly lower hatching success. Overall, our results highlight several potential mechanisms by which low water availability, via changes in host plant quality, may differentially influence P. aegeria populations relative to landscape structure.

  13. Allometric scaling of plant life history.

    PubMed

    Marbà, Núria; Duarte, Carlos M; Agustí, Susana

    2007-10-02

    Plant mortality and birth rates are critical components of plant life history affecting the stability of plant populations and the ecosystems they form. Although allometric theory predicts that both plant birth and mortality rates should be size-dependent, this prediction has not yet been tested across plants ranging the full size spectrum. Here we show that both population mortality and population birth rates scale as the -(1/4) power and plant lifespan as the (1/4) power of plant mass across plant species spanning from the tiniest phototrophs to the largest trees. Whereas the controls on plant lifespans are as yet poorly understood, our findings suggest that plant mortality rates have evolved to match population birth rates, thereby helping to maintain plant communities in equilibrium and optimizing plant life histories.

  14. Hominin life history: reconstruction and evolution

    PubMed Central

    Robson, Shannen L; Wood, Bernard

    2008-01-01

    In this review we attempt to reconstruct the evolutionary history of hominin life history from extant and fossil evidence. We utilize demographic life history theory and distinguish life history variables, traits such as weaning, age at sexual maturity, and life span, from life history-related variables such as body mass, brain growth, and dental development. The latter are either linked with, or can be used to make inferences about, life history, thus providing an opportunity for estimating life history parameters in fossil taxa. We compare the life history variables of modern great apes and identify traits that are likely to be shared by the last common ancestor of Pan-Homo and those likely to be derived in hominins. All great apes exhibit slow life histories and we infer this to be true of the last common ancestor of Pan-Homo and the stem hominin. Modern human life histories are even slower, exhibiting distinctively long post-menopausal life spans and later ages at maturity, pointing to a reduction in adult mortality since the Pan-Homo split. We suggest that lower adult mortality, distinctively short interbirth intervals, and early weaning characteristic of modern humans are derived features resulting from cooperative breeding. We evaluate the fidelity of three life history-related variables, body mass, brain growth and dental development, with the life history parameters of living great apes. We found that body mass is the best predictor of great ape life history events. Brain growth trajectories and dental development and eruption are weakly related proxies and inferences from them should be made with caution. We evaluate the evidence of life history-related variables available for extinct species and find that prior to the transitional hominins there is no evidence of any hominin taxon possessing a body size, brain size or aspects of dental development much different from what we assume to be the primitive life history pattern for the Pan-Homo clade. Data for

  15. Personal Narratives in Life History Research

    ERIC Educational Resources Information Center

    Germeten, Sidsel

    2013-01-01

    In this article I discuss how to create personal narratives in life history research methodology. People tell stories of their lives, and the researchers make these stories into life histories. Based on theoretical perspectives on "discourse" inspired by Michel Foucault, narratives are seen as ways of positioning oneself as a…

  16. Globalization and Life History Research: Fragments of a Life Foretold

    ERIC Educational Resources Information Center

    Tierney, William G.

    2010-01-01

    The goal of this paper is to understand, by way of a life history of one low-income working-class youth, how globalization impacts the working class in a developing nation. The concept of globalization and the method of life history seem diametrically opposed. Globalization is an idea about large social forces that impact the economic and material…

  17. Species and life-history affects the utility of otolith chemical composition to determine natal stream-of-origin in Pacific salmon

    USGS Publications Warehouse

    Zimmerman, Christian E.; Swanson, Heidi K.; Volk, Eric C.; Kent, Adam J.R.

    2013-01-01

    To test the utility of otolith chemical composition as a tool for determining the natal stream of origin for salmon, we examined water chemistry and otoliths of juvenile and adult Chum Salmon Oncorhynchus keta and Coho Salmon O. kisutch from three watersheds (five rivers) in the Norton Sound region of Alaska. The two species are characterized by different life histories: Coho Salmon rear in freshwater for up to 3 years, whereas Chum Salmon emigrate from freshwater shortly after emergence. We used laser ablation (LA) inductively coupled plasma (ICP) mass spectrometry (MS) to quantify element: Ca ratios for Mg, Mn, Zn, Sr, and Ba, and we used multicollector LA-ICP-MS to determine 87Sr:86Sr ratios in otolith regions corresponding to the period of freshwater residence. Significant differences existed in both water and otolith elemental composition, suggesting that otolith composition could be used to discriminate the natal origin of Coho Salmon and Chum Salmon but only when 87Sr:86Sr ratios were included in the discriminant function analyses. The best discriminant model included 87Sr:86Sr ratios, and without 87Sr:86Sr ratios it was difficult to discriminate among watersheds and rivers. Classification accuracy was 80% for Coho Salmon and 68% for Chum Salmon, indicating that this method does not provide sufficient sensitivity to estimate straying rates of Pacific salmon at the scale we studied.

  18. Reconstructing life history of hominids and humans.

    PubMed

    Crews, Douglas E; Gerber, Linda M

    2003-06-01

    Aspects of life history, such as processes and timing of development, age at maturation, and life span are consistently associated with one another across the animal kingdom. Species that develop rapidly tend to mature and reproduce early, have many offspring, and exhibit shorter life spans (r-selection) than those that develop slowly, have extended periods of premature growth, mature later in life, reproduce later and less frequently, have few offspring and/or single births, and exhibit extended life spans (K-selection). In general, primates are among the most K-selected of species. A suite of highly derived life history traits characterizes humans. Among these are physically immature neonates, slowed somatic development both in utero and post-natally, late attainment of reproductive maturity and first birth, and extended post-mature survival. Exactly when, why, and through what types of evolutionary interactions this suite arose is currently the subject of much conjecture and debate. Humankind's biocultural adaptations have helped to structure human life history evolution in unique ways not seen in other animal species. Among all species, life history traits may respond rapidly to alterations in selective pressures through hormonal processes. Selective pressures on life history likely varied widely among hominids and humans over their evolutionary history. This suggests that current patterns of human growth, development, maturation, reproduction, and post-mature survival may be of recent genesis, rather then long-standing adaptations. Thus, life history patterns observed among contemporary human and chimpanzee populations may provide little insight to those that existed earlier in hominid/human evolution.

  19. Statistical analysis of life history calendar data.

    PubMed

    Eerola, Mervi; Helske, Satu

    2016-04-01

    The life history calendar is a data-collection tool for obtaining reliable retrospective data about life events. To illustrate the analysis of such data, we compare the model-based probabilistic event history analysis and the model-free data mining method, sequence analysis. In event history analysis, we estimate instead of transition hazards the cumulative prediction probabilities of life events in the entire trajectory. In sequence analysis, we compare several dissimilarity metrics and contrast data-driven and user-defined substitution costs. As an example, we study young adults' transition to adulthood as a sequence of events in three life domains. The events define the multistate event history model and the parallel life domains in multidimensional sequence analysis. The relationship between life trajectories and excess depressive symptoms in middle age is further studied by their joint prediction in the multistate model and by regressing the symptom scores on individual-specific cluster indices. The two approaches complement each other in life course analysis; sequence analysis can effectively find typical and atypical life patterns while event history analysis is needed for causal inquiries.

  20. Life-history strategies of ungulates

    USGS Publications Warehouse

    Leslie, David M.; Bowyer, R.T.; Kie, J.G.

    1999-01-01

    This Special Feature resulted from a symposium on life-history strategies of ungulates presented at the 78th Annual Meeting of the American Society of Mammalogists in Blacksburg, Virginia, in June 1998. The presentations at the symposium represented only a vignette of the wide variety of life-history strategies that exists among ungulates. The four papers that follow include treatises on birth-site selection of moose (Alces alces), sex-ratio correlates with dimorphism and risk of predation, optimal foraging relative to risk of predation, and the role of density dependence in shaping life-history traits of ungulates. A theme of risk of predation in shaping life-history traits is common to three of four papers.

  1. Impact of Life History on Fear Memory and Extinction

    PubMed Central

    Remmes, Jasmin; Bodden, Carina; Richter, S. Helene; Lesting, Jörg; Sachser, Norbert; Pape, Hans-Christian; Seidenbecher, Thomas

    2016-01-01

    Behavioral profiles are strongly shaped by an individual's whole life experience. The accumulation of negative experiences over lifetime is thought to promote anxiety-like behavior in adulthood (“allostatic load hypothesis”). In contrast, the “mismatch hypothesis” of psychiatric disease suggests that high levels of anxiety-like behavior are the result of a discrepancy between early and late environment. The aim of the present study was to investigate how different life histories shape the expression of anxiety-like behavior and modulate fear memory. In addition, we aimed to clarify which of the two hypotheses can better explain the modulation of anxiety and fear. For this purpose, male mice grew up under either adverse or beneficial conditions during early phase of life. In adulthood they were further subdivided in groups that either matched or mismatched the condition experienced before, resulting in four different life histories. The main results were: (i) Early life benefit followed by late life adversity caused decreased levels of anxiety-like behavior. (ii) Accumulation of adversity throughout life history led to impaired fear extinction learning. Late life adversity as compared to late life benefit mainly affected extinction training, while early life adversity as compared to early life benefit interfered with extinction recall. Concerning anxiety-like behavior, the results do neither support the allostatic load nor the mismatch hypothesis, but rather indicate an anxiolytic effect of a mismatched early beneficial and later adverse life history. In contrast, fear memory was strongly affected by the accumulation of adverse experiences over the lifetime, therefore supporting allostatic load hypothesis. In summary, this study highlights that anxiety-like behavior and fear memory are differently affected by specific combinations of adverse or beneficial events experienced throughout life. PMID:27757077

  2. The Early History of Life

    NASA Astrophysics Data System (ADS)

    Nisbet, E. G.; Fowler, C. M. R.

    2003-12-01

    The youth of the Earth is strange to us. Many of the most fundamental constraints on life may have been different, especially the oxidation state of the surface. Should we suddenly land on its Hadean or early Archean surface by some sci-fi accident, we would not recognize our home. Above, the sky may have been green or some other unworldly color, and above that the weak young Sun might have been unrecognizable to someone trying to identify it from its spectrum. Below, seismology would show a hot, comparatively low-viscosity interior, possibly with a magma ocean in the deeper part of the upper mantle (Drake and Righter, 2002; Nisbet and Walker, 1982), and a core that, though present, was perhaps rather smaller than today. The continents may have been small islands in an icy sea, mostly frozen with some leads of open water, ( Sleep et al., 2001). Into these icy oceans, huge protruding Hawaii-like volcanoes would have poured out vast far-spreading floods of komatiite lavas in immense eruptions that may have created sudden local hypercane storms to disrupt the nearby icebergs. And meteorites would rain down.Or perhaps it was not so strange, nor so violent. The child is father to the man; young Earth was mother to Old Earth. Earth had hydrogen, silicate rock below and on the surface abundant carbon, which her ancient self retains today. Moreover, Earth was oxygen-rich, as today. Today, a tiny part of the oxygen is free, as air; then the oxygen would have been in the mantle while the surface oxygen was used to handcuff the hydrogen as dihydrogen monoxide. Oxygen dihydride is dense, unlikely to fly off to space, and at the poles, rock-forming. Of all the geochemical features that make Earth unique, the initial degassing (Genesis 2 : b) and then the sustained presence of liquid water is the defining oddity of this planet. Early Earth probably also kept much of its carbon, nitrogen, and sulfur as oxide or hydride. And, after the most cataclysmic events had passed, ˜4.5 Ga

  3. America: History and Life Online: History and Much More.

    ERIC Educational Resources Information Center

    Falk, Joyce Duncan

    1983-01-01

    This guide to searching for "America: History and Life," a bibliographic database offering resources on topics in social sciences, humanities, and arts in the United States and Canada, covers subject scope, selection and coverage, document types and records, combined entries, subject indexing, personal names, geographic names, historical periods,…

  4. Life history diversity in Klamath River steelhead

    USGS Publications Warehouse

    Hodge, Brian W.; Wilzbach, Peggy; Duffy, Walter G. G.; Quinones, Rebecca M.; Hobbs, James A.

    2016-01-01

    Oncorhynchus mykiss exhibits a vast array of life histories, which increases its likelihood of persistence by spreading risk of extirpation among different pathways. The Klamath River basin (California–Oregon) provides a particularly interesting backdrop for the study of life history diversity in O. mykiss, in part because the river is slated for a historic and potentially influential dam removal and habitat recolonization project. We used scale and otolith strontium isotope (87Sr/86Sr) analyses to characterize life history diversity in wildO. mykiss from the lower Klamath River basin. We also determined maternal origin (anadromous or nonanadromous) and migratory history (anadromous or nonanadromous) of O. mykiss and compared length and fecundity at age between anadromous (steelhead) and nonanadromous (Rainbow Trout) phenotypes of O. mykiss. We identified a total of 38 life history categories at maturity, which differed in duration of freshwater and ocean rearing, age at maturation, and incidence of repeat spawning. Approximately 10% of adult fish sampled were nonanadromous. Rainbow Trout generally grew faster in freshwater than juvenile steelhead; however, ocean growth afforded adult steelhead greater length and fecundity than adult Rainbow Trout. Although 75% of individuals followed the migratory path of their mother, steelhead produced nonanadromous progeny and Rainbow Trout produced anadromous progeny. Overall, we observed a highly diverse array of life histories among Klamath River O. mykiss. While this diversity should increase population resilience, recent declines in the abundance of Klamath River steelhead suggest that life history diversity alone is not sufficient to stabilize a population. Our finding that steelhead and Rainbow Trout give rise to progeny of the alternate form (1) suggests that dam removal might lead to a facultatively anadromous O. mykiss population in the upper basin and (2) raises the question of whether both forms of

  5. Lemur Biorhythms and Life History Evolution.

    PubMed

    Hogg, Russell T; Godfrey, Laurie R; Schwartz, Gary T; Dirks, Wendy; Bromage, Timothy G

    2015-01-01

    Skeletal histology supports the hypothesis that primate life histories are regulated by a neuroendocrine rhythm, the Havers-Halberg Oscillation (HHO). Interestingly, subfossil lemurs are outliers in HHO scaling relationships that have been discovered for haplorhine primates and other mammals. We present new data to determine whether these species represent the general lemur or strepsirrhine condition and to inform models about neuroendocrine-mediated life history evolution. We gathered the largest sample to date of HHO data from histological sections of primate teeth (including the subfossil lemurs) to assess the relationship of these chronobiological measures with life history-related variables including body mass, brain size, age at first female reproduction, and activity level. For anthropoids, these variables show strong correlations with HHO conforming to predictions, though body mass and endocranial volume are strongly correlated with HHO periodicity in this group. However, lemurs (possibly excepting Daubentonia) do not follow this pattern and show markedly less variability in HHO periodicity and lower correlation coefficients and slopes. Moreover, body mass is uncorrelated, and brain size and activity levels are more strongly correlated with HHO periodicity in these animals. We argue that lemurs evolved this pattern due to selection for risk-averse life histories driven by the unpredictability of the environment in Madagascar. These results reinforce the idea that HHO influences life history evolution differently in response to specific ecological selection regimes.

  6. Deciphering life history transcriptomes in different environments

    PubMed Central

    Etges, William J.; Trotter, Meredith V.; de Oliveira, Cássia C.; Rajpurohit, Subhash; Gibbs, Allen G.; Tuljapurkar, Shripad

    2014-01-01

    We compared whole transcriptome variation in six preadult stages and seven adult female ages in two populations of cactophilic Drosophila mojavensis reared on two host plants in order to understand how differences in gene expression influence standing life history variation. We used Singular Value Decomposition (SVD) to identify dominant trajectories of life cycle gene expression variation, performed pair-wise comparisons of stage and age differences in gene expression across the life cycle, identified when genes exhibited maximum levels of life cycle gene expression, and assessed population and host cactus effects on gene expression. Life cycle SVD analysis returned four significant components of transcriptional variation, revealing functional enrichment of genes responsible for growth, metabolic function, sensory perception, neural function, translation and aging. Host cactus effects on female gene expression revealed population and stage specific differences, including significant host plant effects on larval metabolism and development, as well as adult neurotransmitter binding and courtship behavior gene expression levels. In 3 - 6 day old virgin females, significant up-regulation of genes associated with meiosis and oogenesis was accompanied by down-regulation of genes associated with somatic maintenance, evidence for a life history tradeoff. The transcriptome of D. mojavensis reared in natural environments throughout its life cycle revealed core developmental transitions and genome wide influences on life history variation in natural populations. PMID:25442828

  7. Deciphering life history transcriptomes in different environments.

    PubMed

    Etges, William J; Trotter, Meredith V; de Oliveira, Cássia C; Rajpurohit, Subhash; Gibbs, Allen G; Tuljapurkar, Shripad

    2015-01-01

    We compared whole transcriptome variation in six pre-adult stages and seven adult female ages in two populations of cactophilic Drosophila mojavensis reared on two host plants to understand how differences in gene expression influence standing life history variation. We used singular value decomposition (SVD) to identify dominant trajectories of life cycle gene expression variation, performed pairwise comparisons of stage and age differences in gene expression across the life cycle, identified when genes exhibited maximum levels of life cycle gene expression, and assessed population and host cactus effects on gene expression. Life cycle SVD analysis returned four significant components of transcriptional variation, revealing functional enrichment of genes responsible for growth, metabolic function, sensory perception, neural function, translation and ageing. Host cactus effects on female gene expression revealed population- and stage-specific differences, including significant host plant effects on larval metabolism and development, as well as adult neurotransmitter binding and courtship behaviour gene expression levels. In 3- to 6-day-old virgin females, significant upregulation of genes associated with meiosis and oogenesis was accompanied by downregulation of genes associated with somatic maintenance, evidence for a life history trade-off. The transcriptome of D. mojavensis reared in natural environments throughout its life cycle revealed core developmental transitions and genome-wide influences on life history variation in natural populations.

  8. How life affects the atmosphere

    NASA Technical Reports Server (NTRS)

    Walker, J. C.

    1984-01-01

    The impact of life on the atmosphere is examined through a discussion of the budgets of important atmospheric constituents and the processes that control their concentrations. Life profoundly influences oxygen and a number of minor atmospheric constituents, but many important gases, including those with the greatest effect on global climate, appear to be little altered by biological processes, at least in the steady state.

  9. Life history evolution: successes, limitations, and prospects

    NASA Astrophysics Data System (ADS)

    Stearns, Stephen C.

    Life history theory tries to explain how evolution designs organisms to achieve reproductive success. The design is a solution to an ecological problem posed by the environment and subject to constraints intrinsic to the organism. Work on life histories has expanded the role of phenotypes in evolutionary theory, extending the range of predictions from genetic patterns to whole-organism traits directly connected to fitness. Among the questions answered are the following: Why are organisms small or large? Why do they mature early or late? Why do they have few or many offspring? Why do they have a short or a long life? Why must they grow old and die? The classical approach to life histories was optimization; it has had some convincing empirical success. Recently non-equilibrium approaches involving frequency-dependence, density-dependence, evolutionary game theory, adaptive dynamics, and explicit population dynamics have supplanted optimization as the preferred approach. They have not yet had as much empirical success, but there are logical reasons to prefer them, and they may soon extend the impact of life history theory into population dynamics and interspecific interactions in coevolving communities.

  10. Life History Antecedents of Vocational Indecision.

    ERIC Educational Resources Information Center

    Iaffaldano, Michelle; And Others

    1985-01-01

    Assessed the validity of using systematic life history information to predict three vocational decision-making criteria in 200 college students: vocational decidedness and its two components, vocational identity and vocational maturity. Significant typologies were identified, however, results indicated that the overall construct of vocational…

  11. The life history of neochromosomes revealed

    PubMed Central

    Papenfuss, Anthony T; Thomas, David M

    2015-01-01

    Neochromosomes are a little-studied class of chromosome-scale mutations that drive some cancers. By sequencing isolated neochromosomes from liposarcomas, we recently defined their structure at single-nucleotide resolution and proposed a model for their life history. Here, we summarize that work, highlighting significant aspects and providing historical context and insight into the discovery process. PMID:27308490

  12. ELASTICITY ANALYSIS OF AMPHIBIAN LIFE HISTORIES

    EPA Science Inventory

    By comparing life history parameters (e.g., age at metamorphosis, age at sexual maturation, egg number, longevity) and phenology of different species, we gain valuable insight into why growth rates differ across populations. Although the demography of most amphibians is lacking, ...

  13. Life histories predict coral community disassembly under multiple stressors.

    PubMed

    Darling, Emily S; McClanahan, Timothy R; Côté, Isabelle M

    2013-06-01

    Climate change is reshaping biological communities against a background of existing human pressure. Evaluating the impacts of multiple stressors on community dynamics can be particularly challenging in species-rich ecosystems, such as coral reefs. Here, we investigate whether life-history strategies and cotolerance to different stressors can predict community responses to fishing and temperature-driven bleaching using a 20-year time series of coral assemblages in Kenya. We found that the initial life-history composition of coral taxa largely determined the impacts of bleaching and coral loss. Prior to the 1998 bleaching event, coral assemblages within no-take marine reserves were composed of three distinct life histories - competitive, stress-tolerant and weedy- and exhibited strong declines following bleaching with limited subsequent recovery. In contrast, fished reefs had lower coral cover, fewer genera and were composed of stress-tolerant and weedy corals that were less affected by bleaching over the long term. Despite these general patterns, we found limited evidence for cotolerance as coral genera and life histories were variable in their sensitivities to fishing and bleaching. Overall, fishing and bleaching have reduced coral diversity and led to altered coral communities of 'survivor' species with stress-tolerant and weedy life histories. Our findings are consistent with expectations that climate change interacting with existing human pressure will result in the loss of coral diversity and critical reef habitat.

  14. Honey and honey-based sugars partially affect reproductive trade-offs in parasitoids exhibiting different life-history and reproductive strategies.

    PubMed

    Harvey, Jeffrey A; Essens, Tijl A; Las, Rutger A; van Veen, Cindy; Visser, Bertanne; Ellers, Jacintha; Heinen, Robin; Gols, Rieta

    2016-12-23

    Adult dietary regimes in insects may affect egg production, fecundity and ultimately fitness. This is especially relevant in parasitoid wasps where many species serve as important biological control agents of agricultural pests. Here, we tested the effect of honey and sugar diets on daily fecundity schedules, lifetime reproductive success and longevity in four species of parasitoid wasps when reared on their respective hosts. The parasitoid species were selected based on dichotomies in host usage strategies and reproductive traits. Gelis agilis and G. areator are idiobiont ecto-parasitoids that develop in non-growing hosts, feed on protein-rich host fluids to maximize reproduction as adults and produce small numbers of large eggs. Meteorus pulchricornis and Microplitis mediator are koinobiont endoparasitoids that develop inside the bodies of growing hosts, do not host-feed, and produce greater numbers of small eggs. Parasitoids were reared on diets of either pure honey (containing trace amounts of proteins), heated honey (with denatured proteins) and a honey-mimic containing sugars only. We hypothesized that the benefits of proteins in honey would enhance reproduction in the ectoparasitoids due to their high metabolic investment per egg, but not in the koinobionts. Pure honey diet resulted in higher lifetime fecundity in G. agilis compared with the honey-mimic, whereas in both koinobionts, reproductive success did not vary significantly with diet. Longevity was less affected by diet in all of the parasitoids, although there were variable trade-offs between host access and longevity in the four species. We argue that there are both trait-based and association-specific effects of supplementary nutrients in honey on reproductive investment and success in parasitoid wasps.

  15. Effect of Load History on Fatigue Life.

    DTIC Science & Technology

    1980-06-01

    A number of different loading histories will be investigated to determine their effects on constant amplitude fatigue properties of the selected...previous test results, and at each of the two R ratios. The effect of overloads on constant ampli- tude fatigue life and damage will be investigated ...be investigated . 5.1 FATIGUE TEST RESULTS Constant amplitude fatigue tests were conducted at four R ratios (+0.5, 0.0, -0.5, -1.0) using the

  16. Grandmothering life histories and human pair bonding

    PubMed Central

    Coxworth, James E.; Kim, Peter S.; McQueen, John S.; Hawkes, Kristen

    2015-01-01

    The evolution of distinctively human life history and social organization is generally attributed to paternal provisioning based on pair bonds. Here we develop an alternative argument that connects the evolution of human pair bonds to the male-biased mating sex ratios that accompanied the evolution of human life history. We simulate an agent-based model of the grandmother hypothesis, compare simulated sex ratios to data on great apes and human hunter–gatherers, and note associations between a preponderance of males and mate guarding across taxa. Then we explore a recent model that highlights the importance of mating sex ratios for differences between birds and mammals and conclude that lessons for human evolution cannot ignore mammalian reproductive constraints. In contradiction to our claim that male-biased sex ratios are characteristically human, female-biased ratios are reported in some populations. We consider the likelihood that fertile men are undercounted and conclude that the mate-guarding hypothesis for human pair bonds gains strength from explicit links with our grandmothering life history. PMID:26351687

  17. Professional Identity as Learning Processes in Life Histories. Roskilde University Life History Project Paper.

    ERIC Educational Resources Information Center

    Salling Olesen, Henning

    The question of how to theorize the subjective side of work within a life history perspective was explored. The findings of a study on engineers' subjective recognition of their lives, their education and jobs, and their life perspectives and the findings of a study of continuing education within a number of white-collar and semiprofessional work…

  18. How Will Cancer Affect My Sex Life?

    MedlinePlus

    ... Families How will cancer affect my sex life? Sexual feelings and attitudes vary greatly among people, even ... people have little or no change in their sexual desire and energy level during cancer treatment. Others ...

  19. Significant effects of fishing gear selectivity on fish life history

    NASA Astrophysics Data System (ADS)

    Liang, Zhenlin; Sun, Peng; Yan, Wei; Huang, Liuyi; Tang, Yanli

    2014-06-01

    Over the past few decades, extreme changes have occurred in the characters of exploited fish populations. The majority of these changes have affected the growth traits of fish life history, which include a smaller size-at-age, an earlier age-at-maturation and among others. Currently, the causes of these life history traits changes still require systematic analyses and empirical studies. The explanations that have been cited are merely expressed in terms of fish phenotypic adaptation. It has been claimed that the original traits of fish can be recovered once the intensity of exploitation of the fish is controlled. Sustained environmental and fishing pressure will change the life history traits of most fish species, so the fish individual's traits are still in small size-at-age and at earlier age-at-maturation in exploited fish populations. In this paper, we expressed our view of points that fishing gear has imposed selectivity on fish populations and individuals as various other environmental factors have done and such changes are unrecoverable. According to the existing tend of exploited fish individual's life history traits, we suggested further researches in this field and provided better methods of fishery management and thereby fishery resources protection than those available early.

  20. A Life History of a Korean Adolescent Girl Who Attempted Suicide

    ERIC Educational Resources Information Center

    Yang, Sungeun

    2012-01-01

    The present study explores the life history of a South Korean adolescent girl who attempted suicide. The study focuses on how sociocultural values affected her suicide attempt and how she made meaning out of the experience. The results revealed that her life history was a process of seeking independence and autonomy, and freeing herself from…

  1. Agency and Female Teachers' Career Decisions: A Life History Study of 40 Women

    ERIC Educational Resources Information Center

    Smith, Joan

    2011-01-01

    This article reports on some of the findings of a wider, life history study on the factors affecting the career decisions of 40 female secondary school teachers in England. By using life history interviews, it was possible to gain rich and nuanced insights into the complexity of factors influencing women's career decisions. While acknowledging the…

  2. Predicting life-history adaptations to pollutants

    SciTech Connect

    Maltby, L.

    1995-12-31

    Animals may adapt to pollutant stress so that individuals from polluted environments are less susceptible than those from unpolluted environments. In addition to such direct adaptations, animals may respond to pollutant stress by life-history modifications; so-called indirect adaptations. This paper will demonstrate how, by combining life-history theory and toxicological data, it is possible to predict stress-induced alterations in reproductive output and offspring size. Pollutant-induced alterations in age-specific survival in favor of adults and reductions in juvenile growth, conditions are predicted to select for reduced investment in reproduction and the allocation of this investment into fewer, larger offspring. Field observations on the freshwater crustaceans, Asellus aquaticus and Gammarus pulex, support these predictions. Females from metal-polluted sites had lower investment in reproduction and produced larger offspring than females of the same species from unpolluted sites. Moreover, interpopulation differences in reproductive biology persisted in laboratory cultures indicating that they had a genetic basis and were therefore due to adaptation rather than acclimation. The general applicability of this approach will be considered.

  3. Immune defense and host life history.

    PubMed

    Zuk, Marlene; Stoehr, Andrew M

    2002-10-01

    Recent interest has focused on immune response in an evolutionary context, with particular attention to disease resistance as a life-history trait, subject to trade-offs against other traits such as reproductive effort. Immune defense has several characteristics that complicate this approach, however; for example, because of the risk of autoimmunity, optimal immune defense is not necessarily maximum immune defense. Two important types of cost associated with immunity in the context of life history are resource costs, those related to the allocation of essential but limited resources, such as energy or nutrients, and option costs, those paid not in the currency of resources but in functional or structural components of the organism. Resource and option costs are likely to apply to different aspects of resistance. Recent investigations into possible trade-offs between reproductive effort, particularly sexual displays, and immunity have suggested interesting functional links between the two. Although all organisms balance the costs of immune defense against the requirements of reproduction, this balance works out differently for males than it does for females, creating sex differences in immune response that in turn are related to ecological factors such as the mating system. We conclude that immune response is indeed costly and that future work would do well to include invertebrates, which have sometimes been neglected in studies of the ecology of immune defense.

  4. Individual heterogeneity in life histories and eco-evolutionary dynamics.

    PubMed

    Vindenes, Yngvild; Langangen, Øystein

    2015-05-01

    Individual heterogeneity in life history shapes eco-evolutionary processes, and unobserved heterogeneity can affect demographic outputs characterising life history and population dynamical properties. Demographic frameworks like matrix models or integral projection models represent powerful approaches to disentangle mechanisms linking individual life histories and population-level processes. Recent developments have provided important steps towards their application to study eco-evolutionary dynamics, but so far individual heterogeneity has largely been ignored. Here, we present a general demographic framework that incorporates individual heterogeneity in a flexible way, by separating static and dynamic traits (discrete or continuous). First, we apply the framework to derive the consequences of ignoring heterogeneity for a range of widely used demographic outputs. A general conclusion is that besides the long-term growth rate lambda, all parameters can be affected. Second, we discuss how the framework can help advance current demographic models of eco-evolutionary dynamics, by incorporating individual heterogeneity. For both applications numerical examples are provided, including an empirical example for pike. For instance, we demonstrate that predicted demographic responses to climate warming can be reversed by increased heritability. We discuss how applications of this demographic framework incorporating individual heterogeneity can help answer key biological questions that require a detailed understanding of eco-evolutionary dynamics.

  5. Individual heterogeneity in life histories and eco-evolutionary dynamics

    PubMed Central

    Vindenes, Yngvild; Langangen, Øystein

    2015-01-01

    Individual heterogeneity in life history shapes eco-evolutionary processes, and unobserved heterogeneity can affect demographic outputs characterising life history and population dynamical properties. Demographic frameworks like matrix models or integral projection models represent powerful approaches to disentangle mechanisms linking individual life histories and population-level processes. Recent developments have provided important steps towards their application to study eco-evolutionary dynamics, but so far individual heterogeneity has largely been ignored. Here, we present a general demographic framework that incorporates individual heterogeneity in a flexible way, by separating static and dynamic traits (discrete or continuous). First, we apply the framework to derive the consequences of ignoring heterogeneity for a range of widely used demographic outputs. A general conclusion is that besides the long-term growth rate lambda, all parameters can be affected. Second, we discuss how the framework can help advance current demographic models of eco-evolutionary dynamics, by incorporating individual heterogeneity. For both applications numerical examples are provided, including an empirical example for pike. For instance, we demonstrate that predicted demographic responses to climate warming can be reversed by increased heritability. We discuss how applications of this demographic framework incorporating individual heterogeneity can help answer key biological questions that require a detailed understanding of eco-evolutionary dynamics. PMID:25807980

  6. Martha E. Rogers: a life history.

    PubMed

    Hektor, L M

    1989-01-01

    The 20th century in nursing has focused heavily on theory development. While theorizing about nursing--what it is, and what it is not--can be traced back to Nightingale, Martha E. Rogers' An Introduction to the Theoretical Basis of Nursing (1970) marked the advent of a new era in nursing science. With a view of nursing as a "learned profession," this landmark work staked out a substantive knowledge base for the discipline. The science of unitary human beings proposed by Rogers was a radical departure from all that had come before and is seen by many as pioneering the beginning of a paradigmatic shift within the profession. The purpose of this inquiry is to document the self-described events across the life span of Martha E. Rogers that she perceived as having influenced the development of the science of unitary human beings. A life history approach is utilized and the data are organized chronologically. This life story of Martha E. Rogers is essential to the current and future understanding of the evolution of the culture of nursing. Likewise, more is learned about the nature and process of theory development.

  7. Dynamic Model for Life History of Scyphozoa

    PubMed Central

    Xie, Congbo; Fan, Meng; Wang, Xin; Chen, Ming

    2015-01-01

    A two-state life history model governed by ODEs is formulated to elucidate the population dynamics of jellyfish and to illuminate the triggering mechanism of its blooms. The polyp-medusa model admits trichotomous global dynamic scenarios: extinction, polyps survival only, and both survival. The population dynamics sensitively depend on several biotic and abiotic limiting factors such as substrate, temperature, and predation. The combination of temperature increase, substrate expansion, and predator diminishment acts synergistically to create a habitat that is more favorable for jellyfishes. Reducing artificial marine constructions, aiding predator populations, and directly controlling the jellyfish population would help to manage the jellyfish blooms. The theoretical analyses and numerical experiments yield several insights into the nature underlying the model and shed some new light on the general control strategy for jellyfish. PMID:26114642

  8. Dynamic Model for Life History of Scyphozoa.

    PubMed

    Xie, Congbo; Fan, Meng; Wang, Xin; Chen, Ming

    2015-01-01

    A two-state life history model governed by ODEs is formulated to elucidate the population dynamics of jellyfish and to illuminate the triggering mechanism of its blooms. The polyp-medusa model admits trichotomous global dynamic scenarios: extinction, polyps survival only, and both survival. The population dynamics sensitively depend on several biotic and abiotic limiting factors such as substrate, temperature, and predation. The combination of temperature increase, substrate expansion, and predator diminishment acts synergistically to create a habitat that is more favorable for jellyfishes. Reducing artificial marine constructions, aiding predator populations, and directly controlling the jellyfish population would help to manage the jellyfish blooms. The theoretical analyses and numerical experiments yield several insights into the nature underlying the model and shed some new light on the general control strategy for jellyfish.

  9. A model for brain life history evolution

    PubMed Central

    Lehmann, Laurent

    2017-01-01

    Complex cognition and relatively large brains are distributed across various taxa, and many primarily verbal hypotheses exist to explain such diversity. Yet, mathematical approaches formalizing verbal hypotheses would help deepen the understanding of brain and cognition evolution. With this aim, we combine elements of life history and metabolic theories to formulate a metabolically explicit mathematical model for brain life history evolution. We assume that some of the brain’s energetic expense is due to production (learning) and maintenance (memory) of energy-extraction skills (or cognitive abilities, knowledge, information, etc.). We also assume that individuals use such skills to extract energy from the environment, and can allocate this energy to grow and maintain the body, including brain and reproductive tissues. The model can be used to ask what fraction of growth energy should be allocated at each age, given natural selection, to growing brain and other tissues under various biological settings. We apply the model to find uninvadable allocation strategies under a baseline setting (“me vs nature”), namely when energy-extraction challenges are environmentally determined and are overcome individually but possibly with maternal help, and use modern-human data to estimate model’s parameter values. The resulting uninvadable strategies yield predictions for brain and body mass throughout ontogeny and for the ages at maturity, adulthood, and brain growth arrest. We find that: (1) a me-vs-nature setting is enough to generate adult brain and body mass of ancient human scale and a sequence of childhood, adolescence, and adulthood stages; (2) large brains are favored by intermediately challenging environments, moderately effective skills, and metabolically expensive memory; and (3) adult skill is proportional to brain mass when metabolic costs of memory saturate the brain metabolic rate allocated to skills. PMID:28278153

  10. A model for brain life history evolution.

    PubMed

    González-Forero, Mauricio; Faulwasser, Timm; Lehmann, Laurent

    2017-03-01

    Complex cognition and relatively large brains are distributed across various taxa, and many primarily verbal hypotheses exist to explain such diversity. Yet, mathematical approaches formalizing verbal hypotheses would help deepen the understanding of brain and cognition evolution. With this aim, we combine elements of life history and metabolic theories to formulate a metabolically explicit mathematical model for brain life history evolution. We assume that some of the brain's energetic expense is due to production (learning) and maintenance (memory) of energy-extraction skills (or cognitive abilities, knowledge, information, etc.). We also assume that individuals use such skills to extract energy from the environment, and can allocate this energy to grow and maintain the body, including brain and reproductive tissues. The model can be used to ask what fraction of growth energy should be allocated at each age, given natural selection, to growing brain and other tissues under various biological settings. We apply the model to find uninvadable allocation strategies under a baseline setting ("me vs nature"), namely when energy-extraction challenges are environmentally determined and are overcome individually but possibly with maternal help, and use modern-human data to estimate model's parameter values. The resulting uninvadable strategies yield predictions for brain and body mass throughout ontogeny and for the ages at maturity, adulthood, and brain growth arrest. We find that: (1) a me-vs-nature setting is enough to generate adult brain and body mass of ancient human scale and a sequence of childhood, adolescence, and adulthood stages; (2) large brains are favored by intermediately challenging environments, moderately effective skills, and metabolically expensive memory; and (3) adult skill is proportional to brain mass when metabolic costs of memory saturate the brain metabolic rate allocated to skills.

  11. Emotions, affects and the production of social life.

    PubMed

    Fox, Nick J

    2015-06-01

    While many aspects of social life possess an emotional component, sociology needs to explore explicitly the part emotions play in producing the social world and human history. This paper turns away from individualistic and anthropocentric emphases upon the experience of feelings and emotions, attending instead to an exploration of flows of 'affect' (meaning simply a capacity to affect or be affected) between bodies, things, social institutions and abstractions. It establishes a materialist sociology of affects that acknowledges emotions as a part, but only a part, of a more generalized affective flow that produces bodies and the social world. From this perspective, emotions are not a peculiarly remarkable outcome of the confluence of biology and culture, but part of a continuum of affectivity that links human bodies to their physical and social environment. This enhances sociological understanding of the part emotions play in shaping actions and capacities in many settings of sociological concern.

  12. Maternal warming affects early life stages of an invasive thistle.

    PubMed

    Zhang, R; Gallagher, R S; Shea, K

    2012-09-01

    Maternal environment can influence plant offspring performance. Understanding maternal environmental effects will help to bridge a key gap in the knowledge of plant life cycles, and provide important insights for species' responses under climate change. Here we show that maternal warming significantly affected the early life stages of an invasive thistle, Carduus nutans. Seeds produced by plants grown in warmed conditions had higher germination percentages and shorter mean germination times than those produced by plants under ambient conditions; this difference was most evident at suboptimal germination temperatures. Subsequent seedling emergence was also faster with maternal warming, with no cost to seedling emergence percentage and seedling growth. Our results suggest that maternal warming may accelerate the life cycle of this species via enhanced early life-history stages. These maternal effects on offspring performance, together with the positive responses of the maternal generation, may exacerbate invasions of this species under climate change.

  13. LIFE HISTORY. Age-related mortality explains life history strategies of tropical and temperate songbirds.

    PubMed

    Martin, Thomas E

    2015-08-28

    Life history theory attempts to explain why species differ in offspring number and quality, growth rate, and parental effort. I show that unappreciated interactions of these traits in response to age-related mortality risk challenge traditional perspectives and explain life history evolution in songbirds. Counter to a long-standing paradigm, tropical songbirds grow at similar overall rates to temperate species but grow wings relatively faster. These growth tactics are favored by predation risk, both in and after leaving the nest, and are facilitated by greater provisioning of individual offspring by parents. Increased provisioning of individual offspring depends on partitioning effort among fewer young because of constraints on effort from adult and nest mortality. These growth and provisioning responses to mortality risk finally explain the conundrum of small clutch sizes of tropical birds.

  14. When divergent life histories hybridize: insights into adaptive life-history traits in an annual weed.

    PubMed

    Campbell, Lesley G; Snow, Allison A; Sweeney, Patricia M

    2009-12-01

    *Colonizing weed populations face novel selective environments, which may drive rapid shifts in life history. These shifts may be amplified when colonists are hybrids of species with divergent life histories. Selection on such phenotypically diverse hybrids may create highly fecund weeds. We measured the phenotypic variation, strength of natural selection and evolutionary response of hybrid and nonhybrid weeds. *We created F(1) hybrids of wild radish, an early flowering, small-stemmed weed, and its late-flowering, large-stemmed, crop relative (Raphanus spp.). Replicate wild and hybrid populations were established in an agricultural landscape in Michigan, USA. The consequences of three generations of natural selection were measured in a common garden experiment. *Hybrid populations experienced strong selection for larger, earlier flowering plants whereas selection was relatively weak on wild populations. Large plant size evolved two to three times faster in the hybrid populations than in wild populations, yet hybrid populations did not evolve earlier flowering. Strong selection on size and phenotypic correlations between age at reproduction and size may have limited the response of flowering phenology. *Our findings demonstrate hybridization between species with divergent life histories may catalyse the rapid evolution of certain adaptive, weedy traits while tradeoffs limit the evolution of others.

  15. Variability in the developmental life history of the genus Gorilla.

    PubMed

    Stoinski, Tara S; Perdue, Bonnie; Breuer, Thomas; Hoff, Michael P

    2013-10-01

    Life history is influenced by factors both intrinsic (e.g., body and relative brain size) and extrinsic (e.g., diet, environmental instability) to organisms. In this study, we examine the prediction that energetic risk influences the life history of gorillas. Recent comparisons suggest that the more frugivorous western lowland gorilla shows increased infant dependence, and thus a slower life history, than the primarily folivorous mountain gorilla to buffer against the risk of starvation during periods of food unpredictability. We further tested this hypothesis by incorporating additional life history data from wild western lowland gorillas and captive western lowland gorillas with the assumption that the latter live under ecological conditions of energetic risk that more closely resemble those of mountain gorillas and thus should show faster life histories than wild members of the species. Overall, we found captive western lowland and wild mountain gorillas to have faster developmental life histories than wild western lowland gorillas, weaning their infants approximately a year earlier and thus reducing interbirth intervals by a year. These results provide support that energetic risk plays an important role in determining gorilla life history. Unlike previous assertions, gorillas do not have substantially faster life histories, at least at the genus level, than other great apes. This calls for a re-evaluation of theories concerning comparative ape life history and evolution and highlights the need for data from additional populations that vary in energetic risk.

  16. Primates and the evolution of long, slow life histories.

    PubMed

    Jones, James Holland

    2011-09-27

    Primates are characterized by relatively late ages at first reproduction, long lives and low fertility. Together, these traits define a life-history of reduced reproductive effort. Understanding the optimal allocation of reproductive effort, and specifically reduced reproductive effort, has been one of the key problems motivating the development of life-history theory. Because of their unusual constellation of life-history traits, primates play an important role in the continued development of life-history theory. In this review, I present the evidence for the reduced reproductive effort life histories of primates and discuss the ways that such life-history tactics are understood in contemporary theory. Such tactics are particularly consistent with the predictions of stochastic demographic models, suggesting a key role for environmental variability in the evolution of primate life histories. The tendency for primates to specialize in high-quality, high-variability food items may make them particularly susceptible to environmental variability and explains their low reproductive-effort tactics. I discuss recent applications of life-history theory to human evolution and emphasize the continuity between models used to explain peculiarities of human reproduction and senescence with the long, slow life histories of primates more generally.

  17. The Life History of 21 Breast Cancers

    PubMed Central

    Nik-Zainal, Serena; Van Loo, Peter; Wedge, David C.; Alexandrov, Ludmil B.; Greenman, Christopher D.; Lau, King Wai; Raine, Keiran; Jones, David; Marshall, John; Ramakrishna, Manasa; Shlien, Adam; Cooke, Susanna L.; Hinton, Jonathan; Menzies, Andrew; Stebbings, Lucy A.; Leroy, Catherine; Jia, Mingming; Rance, Richard; Mudie, Laura J.; Gamble, Stephen J.; Stephens, Philip J.; McLaren, Stuart; Tarpey, Patrick S.; Papaemmanuil, Elli; Davies, Helen R.; Varela, Ignacio; McBride, David J.; Bignell, Graham R.; Leung, Kenric; Butler, Adam P.; Teague, Jon W.; Martin, Sancha; Jönsson, Goran; Mariani, Odette; Boyault, Sandrine; Miron, Penelope; Fatima, Aquila; Langerød, Anita; Aparicio, Samuel A.J.R.; Tutt, Andrew; Sieuwerts, Anieta M.; Borg, Åke; Thomas, Gilles; Salomon, Anne Vincent; Richardson, Andrea L.; Børresen-Dale, Anne-Lise; Futreal, P. Andrew; Stratton, Michael R.; Campbell, Peter J.

    2012-01-01

    Summary Cancer evolves dynamically as clonal expansions supersede one another driven by shifting selective pressures, mutational processes, and disrupted cancer genes. These processes mark the genome, such that a cancer's life history is encrypted in the somatic mutations present. We developed algorithms to decipher this narrative and applied them to 21 breast cancers. Mutational processes evolve across a cancer's lifespan, with many emerging late but contributing extensive genetic variation. Subclonal diversification is prominent, and most mutations are found in just a fraction of tumor cells. Every tumor has a dominant subclonal lineage, representing more than 50% of tumor cells. Minimal expansion of these subclones occurs until many hundreds to thousands of mutations have accumulated, implying the existence of long-lived, quiescent cell lineages capable of substantial proliferation upon acquisition of enabling genomic changes. Expansion of the dominant subclone to an appreciable mass may therefore represent the final rate-limiting step in a breast cancer's development, triggering diagnosis. PaperClip PMID:22608083

  18. Life history evolution in social insects: a female perspective.

    PubMed

    Negroni, Matteo Antoine; Jongepier, Evelien; Feldmeyer, Barbara; Kramer, Boris H; Foitzik, Susanne

    2016-08-01

    Social insects are known for their unusual life histories with fecund, long-lived queens and sterile, short-lived workers. We review ultimate factors underlying variation in life history strategies in female social insects, whose social life reshapes common trade-offs, such as the one between fecundity and longevity. Interspecific life history variation is associated with colony size, mediated by changes in division of labour and extrinsic mortality. In addition to the ratio of juvenile to adult mortality, social factors such as queen number influence life history trajectories. We discuss two hypotheses explaining why queen fecundity and lifespan is higher in single-queen societies and suggest further research directions on the evolution of life history variation in social insects.

  19. Personality Polygenes, Positive Affect, and Life Satisfaction.

    PubMed

    Weiss, Alexander; Baselmans, Bart M L; Hofer, Edith; Yang, Jingyun; Okbay, Aysu; Lind, Penelope A; Miller, Mike B; Nolte, Ilja M; Zhao, Wei; Hagenaars, Saskia P; Hottenga, Jouke-Jan; Matteson, Lindsay K; Snieder, Harold; Faul, Jessica D; Hartman, Catharina A; Boyle, Patricia A; Tiemeier, Henning; Mosing, Miriam A; Pattie, Alison; Davies, Gail; Liewald, David C; Schmidt, Reinhold; De Jager, Philip L; Heath, Andrew C; Jokela, Markus; Starr, John M; Oldehinkel, Albertine J; Johannesson, Magnus; Cesarini, David; Hofman, Albert; Harris, Sarah E; Smith, Jennifer A; Keltikangas-Järvinen, Liisa; Pulkki-Råback, Laura; Schmidt, Helena; Smith, Jacqui; Iacono, William G; McGue, Matt; Bennett, David A; Pedersen, Nancy L; Magnusson, Patrik K E; Deary, Ian J; Martin, Nicholas G; Boomsma, Dorret I; Bartels, Meike; Luciano, Michelle

    2016-10-01

    Approximately half of the variation in wellbeing measures overlaps with variation in personality traits. Studies of non-human primate pedigrees and human twins suggest that this is due to common genetic influences. We tested whether personality polygenic scores for the NEO Five-Factor Inventory (NEO-FFI) domains and for item response theory (IRT) derived extraversion and neuroticism scores predict variance in wellbeing measures. Polygenic scores were based on published genome-wide association (GWA) results in over 17,000 individuals for the NEO-FFI and in over 63,000 for the IRT extraversion and neuroticism traits. The NEO-FFI polygenic scores were used to predict life satisfaction in 7 cohorts, positive affect in 12 cohorts, and general wellbeing in 1 cohort (maximal N = 46,508). Meta-analysis of these results showed no significant association between NEO-FFI personality polygenic scores and the wellbeing measures. IRT extraversion and neuroticism polygenic scores were used to predict life satisfaction and positive affect in almost 37,000 individuals from UK Biobank. Significant positive associations (effect sizes <0.05%) were observed between the extraversion polygenic score and wellbeing measures, and a negative association was observed between the polygenic neuroticism score and life satisfaction. Furthermore, using GWA data, genetic correlations of -0.49 and -0.55 were estimated between neuroticism with life satisfaction and positive affect, respectively. The moderate genetic correlation between neuroticism and wellbeing is in line with twin research showing that genetic influences on wellbeing are also shared with other independent personality domains.

  20. Early Adolescent Affect Predicts Later Life Outcomes

    PubMed Central

    Kansky, Jessica; Allen, Joseph P.; Diener, Ed

    2016-01-01

    Background Subjective well-being as a predictor for later behavior and health has highlighted its relationship to health, work performance, and social relationships. However, the majority of such studies neglect the developmental nature of well-being in contributing to important changes across the transition to adulthood. Methods To examine the potential role of subjective well-being as a long-term predictor of critical life outcomes, we examined indicators of positive and negative affect at age 14 as a predictor of relationship, adjustment, self worth, and career outcomes a decade later at ages 23 to 25, controlling for family income and gender. We utilized multi-informant methods including reports from the target participant, close friends, and romantic partners in a demographically diverse community sample of 184 participants. Results Early adolescent positive affect predicted less relationship problems (less self-reported and partner-reported conflict, greater friendship attachment as rated by close peers), healthy adjustment to adulthood (lower levels of depression, anxiety, and loneliness). It also predicted positive work functioning (higher levels of career satisfaction and job competence) and increased self-worth. Negative affect did not significantly predict any of these important life outcomes. In addition to predicting desirable mean levels of later outcomes, early positive affect predicted beneficial changes across time in many outcomes. Conclusions The findings extend early research on the beneficial outcomes of subjective well-being by having an earlier assessment of well-being, including informant reports in measuring a large variety of outcome variables, and by extending the findings to a lower socioeconomic group of a diverse and younger sample. The results highlight the importance of considering positive affect as an important component of subjective well-being distinct from negative affect. PMID:27075545

  1. Interrupting Life History: The Evolution of Relationship within Research

    ERIC Educational Resources Information Center

    Hallett, Ronald E.

    2013-01-01

    In this paper the author explores how relationships are defined within the context of constructing a life history. The life history of Benjamin, a homeless young man transitioning to adulthood, is used to illustrate how difficult it is to define the parameters of the research environment. During an "ethically important moment" in the…

  2. Inadvertent Exemplars: Life History Portraits of Two Socially Just Principals

    ERIC Educational Resources Information Center

    Scanlan, Martin

    2012-01-01

    This study creates life history portraits of two White middle-class native-English-speaking principals demonstrating commitments to social justice in their work in public elementary schools serving disproportionately high populations of students who are marginalized by poverty, race, and linguistic heritage. Through self-reported life histories of…

  3. Reflections on the Life Histories of Today's LGBQ Postsecondary Students

    ERIC Educational Resources Information Center

    Olive, James L.

    2012-01-01

    This qualitative multiple-case study utilized a life history methodology in which written and oral narratives were obtained from six postsecondary students who self-identified as lesbian, gay, bisexual, and/or queer (LGBQ). Through the construction of life histories, the researcher endeavored to understand how past experiences and behaviors shaped…

  4. To Fairly Tell: Social Mobility, Life Histories, and the Anthropologist

    ERIC Educational Resources Information Center

    Benei, Veronique

    2010-01-01

    This article focuses on social agents' own understandings of socio-economic mobility and social achievement, exploring the possibilities offered by the tool of "family" life history in the context of formerly Untouchable communities in western India, Maharashtra. While arguing in favour of family life histories as both resource and…

  5. Armitage Lecture 2011: the design and analysis of life history studies.

    PubMed

    Lawless, Jerald F

    2013-06-15

    Life history studies collect information on events and other outcomes during people's lifetimes. For example, these may be related to childhood development, education, fertility, health, or employment. Such longitudinal studies have constraints on the selection of study members, the duration and frequency of follow-up, and the accuracy and completeness of information obtained. These constraints, along with factors associated with the definition and measurement of certain outcomes, affect our ability to understand, model, and analyze life history processes. My objective here is to discuss and illustrate some issues associated with the design and analysis of life history studies.

  6. Life history linked to immune investment in developing amphibians

    PubMed Central

    Woodhams, Douglas C.; Bell, Sara C.; Bigler, Laurent; Caprioli, Richard M.; Chaurand, Pierre; Lam, Brianna A.; Reinert, Laura K.; Stalder, Urs; Vazquez, Victoria M.; Schliep, Klaus; Hertz, Andreas; Rollins-Smith, Louise A.

    2016-01-01

    The broad diversity of amphibian developmental strategies has been shaped, in part, by pathogen pressure, yet trade-offs between the rate of larval development and immune investment remain poorly understood. The expression of antimicrobial peptides (AMPs) in skin secretions is a crucial defense against emerging amphibian pathogens and can also indirectly affect host defense by influencing the composition of skin microbiota. We examined the constitutive or induced expression of AMPs in 17 species at multiple life-history stages. We found that AMP defenses in tadpoles of species with short larval periods (fast pace of life) were reduced in comparison with species that overwinter as tadpoles and grow to a large size. A complete set of defensive peptides emerged soon after metamorphosis. These findings support the hypothesis that species with a slow pace of life invest energy in AMP production to resist potential pathogens encountered during the long larval period, whereas species with a fast pace of life trade this investment in defense for more rapid growth and development. PMID:27928507

  7. Life history linked to immune investment in developing amphibians.

    PubMed

    Woodhams, Douglas C; Bell, Sara C; Bigler, Laurent; Caprioli, Richard M; Chaurand, Pierre; Lam, Brianna A; Reinert, Laura K; Stalder, Urs; Vazquez, Victoria M; Schliep, Klaus; Hertz, Andreas; Rollins-Smith, Louise A

    2016-01-01

    The broad diversity of amphibian developmental strategies has been shaped, in part, by pathogen pressure, yet trade-offs between the rate of larval development and immune investment remain poorly understood. The expression of antimicrobial peptides (AMPs) in skin secretions is a crucial defense against emerging amphibian pathogens and can also indirectly affect host defense by influencing the composition of skin microbiota. We examined the constitutive or induced expression of AMPs in 17 species at multiple life-history stages. We found that AMP defenses in tadpoles of species with short larval periods (fast pace of life) were reduced in comparison with species that overwinter as tadpoles and grow to a large size. A complete set of defensive peptides emerged soon after metamorphosis. These findings support the hypothesis that species with a slow pace of life invest energy in AMP production to resist potential pathogens encountered during the long larval period, whereas species with a fast pace of life trade this investment in defense for more rapid growth and development.

  8. The Digital Life History Project: Intergenerational Collaborative Research

    ERIC Educational Resources Information Center

    Loe, Meika

    2013-01-01

    This article describes the Digital Life History Project, a 10-week "lab" linked to a course on aging, in which students and community-dwelling elders work together to create a short digital story honoring the elder's life. After two interview sessions, the pair works together to produce a 3- to 5-minute digital life story narrated by the elder.…

  9. Life history strategy influences parasite responses to habitat fragmentation.

    PubMed

    Froeschke, Götz; van der Mescht, Luther; McGeoch, Melodie; Matthee, Sonja

    2013-12-01

    Anthropogenic habitat use is a major threat to biodiversity and is known to increase the abundance of generalist host species such as rodents, which are regarded as potential disease carriers. Parasites have an intimate relationship with their host and the surrounding environment and it is expected that habitat fragmentation will affect parasite infestation levels. We investigated the effect of habitat fragmentation on the ecto- and endoparasitic burdens of a broad niche small mammal, Rhabdomys pumilio, in the Western Cape Province, South Africa. Our aim was to look at the effects of fragmentation on different parasite species with diverse life history characteristics and to determine whether general patterns can be found. Sampling took place within pristine lowland (Fynbos/Renosterveld) areas and at fragmented sites surrounded and isolated by agricultural activities. All arthropod ectoparasites and available gastrointestinal endoparasites were identified. We used conditional autoregressive models to investigate the effects of habitat fragmentation on parasite species richness and abundance of all recovered parasites. Host density and body size were larger in the fragments. Combined ecto- as well as combined endoparasite taxa showed higher parasite species richness in fragmented sites. Parasite abundance was generally higher in the case of R. pumilio individuals in fragmented habitats but it appears that parasites that are more permanently associated with the host's body and those that are host-specific show the opposite trend. Parasite life history is an important factor that needs to be considered when predicting the effects of habitat fragmentation on parasite and pathogen transmission.

  10. "Ant" and "grasshopper" life-history strategies in Saccharomyces cerevisiae.

    PubMed

    Spor, Aymé; Wang, Shaoxiao; Dillmann, Christine; de Vienne, Dominique; Sicard, Delphine

    2008-02-13

    From the evolutionary and ecological points of view, it is essential to distinguish between the genetic and environmental components of the variability of life-history traits and of their trade-offs. Among the factors affecting this variability, the resource uptake rate deserves particular attention, because it depends on both the environment and the genetic background of the individuals. In order to unravel the bases of the life-history strategies in yeast, we grew a collection of twelve strains of Saccharomyces cerevisiae from different industrial and geographical origins in three culture media differing for their glucose content. Using a population dynamics model to fit the change of population size over time, we estimated the intrinsic growth rate (r), the carrying capacity (K), the mean cell size and the glucose consumption rate per cell. The life-history traits, as well as the glucose consumption rate, displayed large genetic and plastic variability and genetic-by-environment interactions. Within each medium, growth rate and carrying capacity were not correlated, but a marked trade-off between these traits was observed over the media, with high K and low r in the glucose rich medium and low K and high r in the other media. The cell size was tightly negatively correlated to carrying capacity in all conditions. The resource consumption rate appeared to be a clear-cut determinant of both the carrying capacity and the cell size in all media, since it accounted for 37% to 84% of the variation of those traits. In a given medium, the strains that consume glucose at high rate have large cell size and low carrying capacity, while the strains that consume glucose at low rate have small cell size but high carrying capacity. These two contrasted behaviors may be metaphorically defined as "ant" and "grasshopper" strategies of resource utilization. Interestingly, a strain may be "ant" in one medium and "grasshopper" in another. These life-history strategies are discussed

  11. Narratives from within: An Arendtian Approach to Life Histories and the Writing of History

    ERIC Educational Resources Information Center

    Tamboukou, Maria

    2010-01-01

    In this paper I draw on my current research of writing a genealogy of women artists, focusing in particular on the life history of the American working-class artist, May Stevens (1924-). I am particularly interested in how an analysis of the textual and visual narratives in her work, seen in the context of her life history, can intervene in the…

  12. From metamorphosis to maturity in complex life cycles: equal performance of different juvenile life history pathways.

    PubMed

    Schmidt, Benedikt R; Hödl, Walter; Schaub, Michael

    2012-03-01

    Performance in one stage of a complex life cycle may affect performance in the subsequent stage. Animals that start a new stage at a smaller size than conspecifics may either always remain smaller or they may be able to "catch up" through plasticity, usually elevated growth rates. We study how size at and date of metamorphosis affected subsequent performance in the terrestrial juvenile stage and lifetime fitness of spadefoot toads (Pelobates fuscus). We analyzed capture-recapture data of > 3000 individuals sampled during nine years with mark-recapture models to estimate first-year juvenile survival probabilities and age-specific first-time breeding probabilities of toads, followed by model selection to assess whether these probabilities were correlated with size at and date of metamorphosis. Males attained maturity after two years, whereas females reached maturity 2-4 years after metamorphosis. Age at maturity was weakly correlated with metamorphic traits. In both sexes, first-year juvenile survival depended positively on date of metamorphosis and, in males, also negatively on size at metamorphosis. In males, toads that metamorphosed early at a small size had the highest probability to reach maturity. However, because very few toadlets metamorphosed early, the vast majority of male metamorphs had a very similar probability to reach maturity. A matrix projection model constructed for females showed that different juvenile life history pathways resulted in similar lifetime fitness. We found that the effects of date of and size at metamorphosis on different juvenile traits cancelled each other out such that toads that were small or large at metamorphosis had equal performance. Because the costs and benefits of juvenile life history pathways may also depend on population fluctuations, ample phenotypic variation in life history traits may be maintained.

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

    PubMed

    Audzijonyte, Asta; Kuparinen, Anna

    2016-08-01

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

  14. Connecting proximate mechanisms and evolutionary patterns: pituitary gland size and mammalian life history.

    PubMed

    Kamilar, J M; Tecot, S R

    2015-11-01

    At the proximate level, hormones are known to play a critical role in influencing the life history of mammals, including humans. The pituitary gland is directly responsible for producing several hormones, including those related to growth and reproduction. Although we have a basic understanding of how hormones affect life history characteristics, we still have little knowledge of this relationship in an evolutionary context. We used data from 129 mammal species representing 14 orders to investigate the relationship between pituitary gland size and life history variation. Because pituitary gland size should be related to hormone production and action, we predicted that species with relatively large pituitaries should be associated with fast life histories, especially increased foetal and post-natal growth rates. Phylogenetic analyses revealed that total pituitary size and the size of the anterior lobe of the pituitary significantly predicted a life history axis that was correlated with several traits including body mass, and foetal and post-natal growth rates. Additional models directly examining the association between relative pituitary size and growth rates produced concordant results. We also found that relative pituitary size variation across mammals was best explained by an Ornstein-Uhlenbeck model of evolution, suggesting an important role of stabilizing selection. Our results support the idea that the size of the pituitary is linked to life history variation through evolutionary time. This pattern is likely due to mediating hormone levels but additional work is needed. We suggest that future investigations incorporating endocrine gland size may be critical for understanding life history evolution.

  15. The plastic fly: the effect of sustained fluctuations in adult food supply on life-history traits.

    PubMed

    van den Heuvel, J; Zandveld, J; Mulder, M; Brakefield, P M; Kirkwood, T B L; Shanley, D P; Zwaan, B J

    2014-11-01

    Many adult traits in Drosophila melanogaster show phenotypic plasticity, and the effects of diet on traits such as lifespan and reproduction are well explored. Although plasticity in response to food is still present in older flies, it is unknown how sustained environmental variation affects life-history traits. Here, we explore how such life-long fluctuations of food supply affect weight and survival in groups of flies and affect weight, survival and reproduction in individual flies. In both experiments, we kept adults on constant high or low food and compared these to flies that experienced fluctuations of food either once or twice a week. For these 'yoyo' groups, the initial food level and the duration of the dietary variation differed during adulthood, creating four 'yoyo' fly groups. In groups of flies, survival and weight were affected by adult food. However, for individuals, survival and reproduction, but not weight, were affected by adult food, indicating that single and group housing of female flies affects life-history trajectories. Remarkably, both the manner and extent to which life-history traits varied in relation to food depended on whether flies initially experienced high or low food after eclosion. We therefore conclude that the expression of life-history traits in adult life is affected not only by adult plasticity, but also by early adult life experiences. This is an important but often overlooked factor in studies of life-history evolution and may explain variation in life-history experiments.

  16. The evolution of life history trade-offs in viruses.

    PubMed

    Goldhill, Daniel H; Turner, Paul E

    2014-10-01

    Viruses can suffer 'life-history' trade-offs that prevent simultaneous improvement in fitness traits, such as improved intrahost reproduction at the expense of reduced extrahost survival. Here we examine reproduction-survival trade-offs and other trait compromises, highlighting that experimental evolution can reveal trade-offs and their associated mechanisms. Whereas 'curse of the pharaoh' (high virulence with extreme stability) may generally apply for viruses of eukaryotes, we suggest phages are instead likely to suffer virulence/stability trade-offs. We examine how survival/reproduction trade-offs in viruses are affected by environmental stressors, proteins governing viral host range, and organization of the virus genome. Future studies incorporating comparative biology, experimental evolution, and structural biology, could thoroughly determine how viral trade-offs evolve, and whether they transiently or permanently constrain virus adaptation.

  17. Improved viability of populations with diverse life-history portfolios.

    PubMed

    Greene, Correigh M; Hall, Jason E; Guilbault, Kimberly R; Quinn, Thomas P

    2010-06-23

    A principle shared by both economists and ecologists is that a diversified portfolio spreads risk, but this idea has little empirical support in the field of population biology. We found that population growth rates (recruits per spawner) and life-history diversity as measured by variation in freshwater and ocean residency were negatively correlated across short time periods (one to two generations), but positively correlated at longer time periods, in nine Bristol Bay sockeye salmon populations. Further, the relationship between variation in growth rate and life-history diversity was consistently negative. These findings strongly suggest that life-history diversity can both increase production and buffer population fluctuations, particularly over long time periods. Our findings provide new insights into the importance of biocomplexity beyond spatio-temporal aspects of populations, and suggest that maintaining diverse life-history portfolios of populations may be crucial for their resilience to unfavourable conditions like habitat loss and climate change.

  18. Improved viability of populations with diverse life-history portfolios

    PubMed Central

    Greene, Correigh M.; Hall, Jason E.; Guilbault, Kimberly R.; Quinn, Thomas P.

    2010-01-01

    A principle shared by both economists and ecologists is that a diversified portfolio spreads risk, but this idea has little empirical support in the field of population biology. We found that population growth rates (recruits per spawner) and life-history diversity as measured by variation in freshwater and ocean residency were negatively correlated across short time periods (one to two generations), but positively correlated at longer time periods, in nine Bristol Bay sockeye salmon populations. Further, the relationship between variation in growth rate and life-history diversity was consistently negative. These findings strongly suggest that life-history diversity can both increase production and buffer population fluctuations, particularly over long time periods. Our findings provide new insights into the importance of biocomplexity beyond spatio-temporal aspects of populations, and suggest that maintaining diverse life-history portfolios of populations may be crucial for their resilience to unfavourable conditions like habitat loss and climate change. PMID:20007162

  19. A database of life-history traits of European amphibians

    PubMed Central

    Moulherat, Sylvain; Calvez, Olivier; Stevens, Virginie M; Clobert, Jean; Schmeller, Dirk S

    2014-01-01

    Abstract In the current context of climate change and landscape fragmentation, efficient conservation strategies require the explicit consideration of life history traits. This is particularly true for amphibians, which are highly threatened worldwide, composed by more than 7400 species, which is constitute one of the most species-rich vertebrate groups. The collection of information on life history traits is difficult due to the ecology of species and remoteness of their habitats. It is therefore not surprising that our knowledge is limited, and missing information on certain life history traits are common for in this species group. We compiled data on amphibian life history traits from literature in an extensive database with morphological and behavioral traits, habitat preferences and movement abilities for 86 European amphibian species (50 Anuran and 36 Urodela species). When it were available, we reported data for males, females, juveniles and tadpoles. Our database may serve as an important starting point for further analyses regarding amphibian conservation. PMID:25425939

  20. How life affects the geochemical cycle of carbon

    NASA Technical Reports Server (NTRS)

    Walker, James C. G.

    1992-01-01

    Developing a quantitative understanding of the biogeochemical cycles of carbon as they have worked throughout Earth history on various time scales, how they have been affected by biological evolution, and how changes in the carbon content of ocean and atmosphere may have affected climate and the evolution of life are the goals of the research. Theoretical simulations were developed that can be tuned to reproduce such data as exist and, once tuned, can be used to predict properties that have not yet been observed. This is an ongoing process, in which models and results are refined as new data and interpretations become available and as understanding of the global system improves. Results of the research are described in several papers which were published or submitted for publication. These papers are summarized. Future research plans are presented.

  1. Life in varying environments: experimental evidence for delayed effects of juvenile environment on adult life history.

    PubMed

    Helle, Heikki; Koskela, Esa; Mappes, Tapio

    2012-05-01

    1. The effects of environment experienced during early development on phenotype as an adult has started to gain vast amounts of interest in various taxa. Some evidence on long-term effects of juvenile environment is available, but replicated experimental studies in wild animals are still lacking. 2. Here we report the first replicated experiment in wild mammals which examines the long-term effects of juvenile and adult environments on individual fitness (reproduction, survival and health). The early development of bank vole (Myodes glareolus) individuals took place in either food-supplemented or un-supplemented outdoor enclosures. After the summer, adult individuals were reciprocally changed to either a similar or opposite resource environment to overwinter. 3. Adult environment had an overriding effect on reproductive success of females so that females overwintering in food-supplemented enclosures had a higher probability of breeding and advanced the initiation of breeding. However, the characteristics of their litters were determined by juvenile environment: females initially grown in food-supplemented conditions subsequently produced larger litters with bigger pups and a male-biased sex ratio. 4. In males, individuals growing in un-supplemented conditions had the highest survival irrespective of adult environment during winter, whereas in females, neither the juvenile nor adult environments affected their survival significantly. The physiological condition of voles in spring, as determined by haematological parameters, was also differentially affected by juvenile (plasma proteins and male testosterone) and adult (haematocrit) environments. 5. Our results suggest that (i) life-history trajectories of voles are not strictly specialized to a certain environment and (ii) the plastic life-history responses to present conditions can actually be caused by delayed effects of the juvenile environment. More generally, the results are important for understanding

  2. Life history diversity and evolution in the Asterinidae.

    PubMed

    Byrne, Maria

    2006-06-01

    Asterinid sea stars have the greatest range of life histories known for the Asteroidea. Larval form in these sea stars has been modified in association with selection for planktonic, benthic, or intergonadal developmental habitats. Life history data are available for 31 species and molecular data for 28 of these. These data were used to assess life history evolution and relationships among asterinid clades. Lecithotrophy is prevalent in Asterinidae, with at least 6 independent origins of this developmental mode. Morphological differences in the attachment complex of brachiolaria larvae were evident among species with planktonic lecithotrophy. Some features are clade specific while others are variable within clades. Benthic brachiolariae are similar in Aquilonastra and Parvulastra with tripod-shaped larvae, while the bilobed sole-shaped larvae of Asterina species appear unique to this genus. Multiple transitions and pathways have been involved in the evolution of lecithotropy in the Asterinidae. Although several genera have a species with a planktonic feeding larva in a basal phylogenetic position, relative to species with planktonic or benthic lecithotrophy, there is little evidence for the expected life history transformation series from planktonic feeding, to planktonic non-feeding, to benthic non-feeding development. Intragonadal development, a life history pattern unique to the Asterinidae, arose three times through ancestors with benthic or pelagic lecithotrophy. Evolution of lecithotrophy appears more prevalent in the Asterinidae than other asteroid families. As diverse modes of development are discerned in cryptic species complexes, new insights into life history evolution in the Asterinidae are being generated.

  3. [Severe depression : life events, patient history].

    PubMed

    Lançon, C

    2009-12-01

    The relationships between severe depression, life events and personality are complex. However, sexual abuse and maltreatment during childhood contribute towards vulnerability to depressive disorders. Maltreatment in childhood does not appear to be linked to any particular personality disorder. An < insecure > type of bonding appears to be a vulnerability factor both for anxiety and depressive disorders in adulthood.

  4. Seed after-ripening and dormancy determine adult life history independently of germination timing.

    PubMed

    de Casas, Rafael Rubio; Kovach, Katherine; Dittmar, Emily; Barua, Deepak; Barco, Brenden; Donohue, Kathleen

    2012-05-01

    • Seed dormancy can affect life history through its effects on germination time. Here, we investigate its influence on life history beyond the timing of germination. • We used the response of Arabidopsis thaliana to chilling at the germination and flowering stages to test the following: how seed dormancy affects germination responses to the environment; whether variation in dormancy affects adult phenology independently of germination time; and whether environmental cues experienced by dormant seeds have an effect on adult life history. • Dormancy conditioned the germination response to low temperatures, such that prolonged periods of chilling induced dormancy in nondormant seeds, but stimulated germination in dormant seeds. The alleviation of dormancy through after-ripening was associated with earlier flowering, independent of germination date. Experimental dormancy manipulations showed that prolonged chilling at the seed stage always induced earlier flowering, regardless of seed dormancy. Surprisingly, this effect of seed chilling on flowering time was observed even when low temperatures did not induce germination. • In summary, seed dormancy influences flowering time and hence life history independent of its effects on germination timing. We conclude that the seed stage has a pronounced effect on life history, the influence of which goes well beyond the timing of germination.

  5. Mathematics and Life: Lessons from History.

    ERIC Educational Resources Information Center

    Gellert, Uwe

    2001-01-01

    Analyzes three stories in order to sensitize for possible characteristics of interrelations between mathematics, technology, science, culture, and society. Demonstrates how specific socio-cultural conditions affect the development of mathematics and technology as well as their use. Discusses the use of mathematics and ways in which mathematics,…

  6. Developmental and Evolutionary History Affect Survival in Stressful Environments

    PubMed Central

    Hopkins, Gareth R.; Brodie, Edmund D.; French, Susannah S.

    2014-01-01

    The world is increasingly impacted by a variety of stressors that have the potential to differentially influence life history stages of organisms. Organisms have evolved to cope with some stressors, while with others they have little capacity. It is thus important to understand the effects of both developmental and evolutionary history on survival in stressful environments. We present evidence of the effects of both developmental and evolutionary history on survival of a freshwater vertebrate, the rough-skinned newt (Taricha granulosa) in an osmotically stressful environment. We compared the survival of larvae in either NaCl or MgCl2 that were exposed to salinity either as larvae only or as embryos as well. Embryonic exposure to salinity led to greater mortality of newt larvae than larval exposure alone, and this reduced survival probability was strongly linked to the carry-over effect of stunted embryonic growth in salts. Larval survival was also dependent on the type of salt (NaCl or MgCl2) the larvae were exposed to, and was lowest in MgCl2, a widely-used chemical deicer that, unlike NaCl, amphibian larvae do not have an evolutionary history of regulating at high levels. Both developmental and evolutionary history are critical factors in determining survival in this stressful environment, a pattern that may have widespread implications for the survival of animals increasingly impacted by substances with which they have little evolutionary history. PMID:24748021

  7. Development under elevated pCO2 conditions does not affect lipid utilization and protein content in early life-history stages of the purple sea urchin, Strongylocentrotus purpuratus.

    PubMed

    Matson, Paul G; Yu, Pauline C; Sewell, Mary A; Hofmann, Gretchen E

    2012-12-01

    Ocean acidification (OA) is expected to have a major impact on marine species, particularly during early life-history stages. These effects appear to be species-specific and may include reduced survival, altered morphology, and depressed metabolism. However, less information is available regarding the bioenergetics of development under elevated CO(2) conditions. We examined the biochemical and morphological responses of Strongylocentrotus purpuratus during early development under ecologically relevant levels of pCO(2) (365, 1030, and 1450 μatm) that may occur during intense upwelling events. The principal findings of this study were (1) lipid utilization rates and protein content in S. purpuratus did not vary with pCO(2); (2) larval growth was reduced at elevated pCO(2) despite similar rates of energy utilization; and (3) relationships between egg phospholipid content and larval length were found under control but not high pCO(2) conditions. These results suggest that this species may either prioritize endogenous energy toward development and physiological function at the expense of growth, or that reduced larval length may be strictly due to higher costs of growth under OA conditions. This study highlights the need to further expand our knowledge of the physiological mechanisms involved in OA response in order to better understand how present populations may respond to global environmental change.

  8. Hyperthermophiles in the history of life

    PubMed Central

    Stetter, Karl O

    2006-01-01

    Today, hyperthermophilic (‘superheat-loving’) bacteria and archaea are found within high-temperature environments, representing the upper temperature border of life. They grow optimally above 80°C and exhibit an upper temperature border of growth up to 113°C. Members of the genera, Pyrodictium and Pyrolobus, survive at least 1 h of autoclaving. In their basically anaerobic environments, hyperthermophiles (HT) gain energy by inorganic redox reactions employing compounds like molecular hydrogen, carbon dioxide, sulphur and ferric and ferrous iron. Based on their growth requirements, HT could have existed already on the early Earth about 3.9 Gyr ago. In agreement, within the phylogenetic tree of life, they occupy all the short deep branches closest to the root. The earliest archaeal phylogenetic lineage is represented by the extremely tiny members of the novel kingdom of Nanoarchaeota, which thrive in submarine hot vents. HT are very tough survivors, even in deep-freezing at −140°C. Therefore, during impact ejecta, they could have been successfully transferred to other planets and moons through the coldness of space. PMID:17008222

  9. Life history evolution and comparative developmental biology of echinoderms.

    PubMed

    Hart, Michael W

    2002-01-01

    Evolutionary biologists studying life history variation have used echinoderms in experimental, laboratory, and field studies of life history evolution. This focus on echinoderms grew originally from the tradition of comparative embryology, in which echinoderms were central. The tools for obtaining and manipulating echinoderm gametes and larvae were taken directly from comparative embryological research. In addition, the comparative embryologists employed a diverse array of echinoderms, not a few model species, and this diversity has led to a broad understanding of the development, function, and evolution of echinoderm larvae. As a result, this branch of life history evolution has deep roots in comparative developmental biology of echinoderms. Here two main aspects of this relationship are reviewed. The first is a broad range of studies of fertilization biology, dispersal, population genetics, functional morphology, and asexual reproduction in which developmental biologists might take a keen interest because of the historical origins of this research in echinoderm comparative embryology. The second is a similarly broad variety of topics in life history research in which evolutionary biologists require techniques or data from developmental biology in order to make progress on understanding patterns of life history variation among echinoderm species and higher taxa. Both sets of topics provide opportunities for interaction and collaboration.

  10. The Crowded Life Is a Slow Life: Population Density and Life History Strategy.

    PubMed

    Sng, Oliver; Neuberg, Steven L; Varnum, Michael E W; Kenrick, Douglas T

    2017-01-09

    The world population has doubled over the last half century. Yet, research on the psychological effects of human population density, once a popular topic, has decreased over the past few decades. Applying a fresh perspective to an old topic, we draw upon life history theory to examine the effects of population density. Across nations and across the U.S. states (Studies 1 and 2), we find that dense populations exhibit behaviors corresponding to a slower life history strategy, including greater future-orientation, greater investment in education, more long-term mating orientation, later marriage age, lower fertility, and greater parental investment. In Studies 3 and 4, experimentally manipulating perceptions of high density led individuals to become more future-oriented. Finally, in Studies 5 and 6, experimentally manipulating perceptions of high density seemed to lead to life-stage-specific slower strategies, with college students preferring to invest in fewer rather than more relationship partners, and an older MTurk sample preferring to invest in fewer rather than more children. This research sheds new insight on the effects of density and its implications for human cultural variation and society at large. (PsycINFO Database Record

  11. Life history of amphibians and gravity.

    PubMed

    Naitoh, Tomio; Yamashita, Masamichi; Wassersug, Richard J

    2004-11-01

    Anurans hold a unique position in vertebrate phylogeny, as they made the major transition from water to land. Through evolution they have acquired fundamental mechanisms to adapt to terrestrial gravity. Such mechanisms are now shared among other terrestrial vertebrates derived from ancestral amphibians. Space research, using amphibians as a model animal, is significant based on the following aspects: (1) Anuran amphibians show drastic changes in their living niche during their metamorphosis. Environments for tadpoles and for terrestrial life of frogs are quite different in terms of gravity and its associated factors. (2) Certain tadpoles, such as Rhacophorus viridis amamiensis, have a transparent abdominal wall. Thus visceral organs and their motion can be observed in these animals in non-invasive manner through their transparent abdominal skin. This feature enables biologists to evaluate the physiological state of these amphibians and study the autonomic control of visceral organs. It is also feasible for space biologists to examine how such autonomic regulation could be altered by microgravity and exposure to the space environment.

  12. Random walks in the history of life

    PubMed Central

    Cornette, James L.; Lieberman, Bruce S.

    2004-01-01

    The simplest null hypothesis for evolutionary time series is that the observed data follow a random walk. We examined whether aspects of Sepkoski's compilation of marine generic diversity depart from a random walk by using statistical tests from econometrics. Throughout most of the Phanerozoic, the random-walk null hypothesis is not rejected for marine diversity, accumulated origination or accumulated extinction, suggesting that either these variables were correlated with environmental variables that follow a random walk or so many mechanisms were affecting these variables, in different ways, that the resultant trends appear random. The only deviation from this pattern involves rejection of the null hypothesis for roughly the last 75 million years for the diversity and accumulated origination time series. PMID:14684835

  13. Anthropogenic natal environmental effects on life histories in a wild bird population.

    PubMed

    Cartwright, Samantha J; Nicoll, Malcolm A C; Jones, Carl G; Tatayah, Vikash; Norris, Ken

    2014-03-03

    Recent work suggests that the environment experienced in early life can alter life histories in wild populations, but our understanding of the processes involved remains limited. Since anthropogenic environmental change is currently having a major impact on wild populations, this raises the possibility that life histories may be influenced by human activities that alter environmental conditions in early life. Whether this is the case and the processes involved remain unexplored in wild populations. Using 23 years of longitudinal data on the Mauritius kestrel (Falco punctatus), a tropical forest specialist, we found that females born in territories affected by anthropogenic habitat change shifted investment in reproduction to earlier in life at the expense of late life performance. They also had lower survival rates as young adults. This shift in life history strategy appears to be adaptive, because fitness was comparable to that of other females experiencing less anthropogenic modification in their natal environment. Our results suggest that human activities can leave a legacy on wild birds through natal environmental effects. Whether these legacies have a detrimental effect on populations will depend on life history responses and the extent to which these reduce individual fitness.

  14. Unification Theory of Optimal Life Histories and Linear Demographic Models in Internal Stochasticity

    PubMed Central

    Oizumi, Ryo

    2014-01-01

    Life history of organisms is exposed to uncertainty generated by internal and external stochasticities. Internal stochasticity is generated by the randomness in each individual life history, such as randomness in food intake, genetic character and size growth rate, whereas external stochasticity is due to the environment. For instance, it is known that the external stochasticity tends to affect population growth rate negatively. It has been shown in a recent theoretical study using path-integral formulation in structured linear demographic models that internal stochasticity can affect population growth rate positively or negatively. However, internal stochasticity has not been the main subject of researches. Taking account of effect of internal stochasticity on the population growth rate, the fittest organism has the optimal control of life history affected by the stochasticity in the habitat. The study of this control is known as the optimal life schedule problems. In order to analyze the optimal control under internal stochasticity, we need to make use of “Stochastic Control Theory” in the optimal life schedule problem. There is, however, no such kind of theory unifying optimal life history and internal stochasticity. This study focuses on an extension of optimal life schedule problems to unify control theory of internal stochasticity into linear demographic models. First, we show the relationship between the general age-states linear demographic models and the stochastic control theory via several mathematical formulations, such as path–integral, integral equation, and transition matrix. Secondly, we apply our theory to a two-resource utilization model for two different breeding systems: semelparity and iteroparity. Finally, we show that the diversity of resources is important for species in a case. Our study shows that this unification theory can address risk hedges of life history in general age-states linear demographic models. PMID:24945258

  15. Prey nutrient composition has different effects on Pardosa wolf spiders with dissimilar life histories.

    PubMed

    Jensen, Kim; Mayntz, David; Toft, Søren; Raubenheimer, David; Simpson, Stephen J

    2011-03-01

    The nutritional composition of prey is known to influence predator life histories, but how the life history strategies of predators affect their susceptibility to nutrient imbalance is less investigated. We used two wolf spider species with different life histories as model predators: Pardosa amentata, which have a fixed annual life cycle, and Pardosa prativaga, which reproduce later and can extend development across 2 years. We fed juvenile spiders of the two species ad libitum diets of one of six Drosophila melanogaster fly types varying in lipid:protein composition during three instars, from the start of the second instar until the fifth instar moult. We then tested for interactions between predator species and prey nutrient composition on several life history parameters. P. amentata completed the three instars faster and grew larger carapaces and heavier body masses than P. prativaga, but the two species responded differently to variation in prey lipid:protein ratio. Duration of the instars increased when feeding on protein-poor prey in P. amentata, but was unaffected by diet in P. prativaga. Likewise, the effect of diet on body composition was more pronounced in P. amentata than in P. prativaga. Prey nutrient composition thus affected the two species differently. During macronutrient imbalance P. amentata appear to prioritize high growth rates while experiencing highly variable body compositions, whereas P. prativaga maintain more constant body compositions and have slower growth. These can be seen as different consequences of a fixed annual and a plastic annual-biennial life cycle.

  16. Planetary Biology-Paleontological, Geological, and Molecular Histories of Life

    NASA Astrophysics Data System (ADS)

    Benner, Steven A.; Caraco, M. Daniel; Thomson, J. Michael; Gaucher, Eric A.

    2002-05-01

    The history of life on Earth is chronicled in the geological strata, the fossil record, and the genomes of contemporary organisms. When examined together, these records help identify metabolic and regulatory pathways, annotate protein sequences, and identify animal models to develop new drugs, among other features of scientific and biomedical interest. Together, planetary analysis of genome and proteome databases is providing an enhanced understanding of how life interacts with the biosphere and adapts to global change.

  17. Planetary biology--paleontological, geological, and molecular histories of life.

    PubMed

    Benner, Steven A; Caraco, M Daniel; Thomson, J Michael; Gaucher, Eric A

    2002-05-03

    The history of life on Earth is chronicled in the geological strata, the fossil record, and the genomes of contemporary organisms. When examined together, these records help identify metabolic and regulatory pathways, annotate protein sequences, and identify animal models to develop new drugs, among other features of scientific and biomedical interest. Together, planetary analysis of genome and proteome databases is providing an enhanced understanding of how life interacts with the biosphere and adapts to global change.

  18. Snake River Fall Chinook Salmon Life History Investigations, Annual Report 2008.

    SciTech Connect

    Tiffan, Kenneth F.; Connor, William P.; Bellgraph, Brian J.

    2009-09-15

    This study was initiated to provide empirical data and analyses on the dam passage timing, travel rate, survival, and life history variation of fall Chinook salmon that are produced in the Clearwater River. The area of interest for this study focuses on the lower four miles of the Clearwater River and its confluence with the Snake River because this is an area where many fish delay their seaward migration. The goal of the project is to increase our understanding of the environmental and biological factors that affect juvenile life history of fall Chinook salmon in the Clearwater River. The following summaries are provided for each of the individual chapters in this report.

  19. Life-history syndromes: integrating dispersal through space and time.

    PubMed

    Buoro, Mathieu; Carlson, Stephanie M

    2014-06-01

    Recent research has highlighted interdependencies between dispersal and other life-history traits, i.e. dispersal syndromes, thereby revealing constraints on the evolution of dispersal and opportunities for improved ability to predict dispersal by considering suites of dispersal-related traits. This review adds to the growing list of life-history traits linked to spatial dispersal by emphasising the interdependence between dispersal through space and time, i.e. life-history diversity that distributes individuals into separate reproductive events. We reviewed the literature that has simultaneously investigated spatial and temporal dispersal to examine the prediction that traits of these two dispersal strategies are negatively correlated. Our results suggest that negative covariation is widely anticipated from theory. Empirical studies often reported evidence of weak negative covariation, although more complicated patterns were also evident, including across levels of biological organisation. Existing literature has largely focused on plants with dormancy capability, one or two phases of the dispersal process (emigration and/or transfer) and a single level of biological organisation (theory: individual; empirical: species). We highlight patterns of covariation across levels of organisation and conclude with a discussion of the consequences of dispersal through space and time and future research areas that should improve our understanding of dispersal-related life-history syndromes.

  20. Life-history evolution in ants: the case of Cardiocondyla.

    PubMed

    Heinze, Jürgen

    2017-03-15

    Ants are important components of most terrestrial habitats, and a better knowledge of the diversity of their life histories is essential to understand many aspects of ecosystem functioning. The myrmicine genus Cardiocondyla shows a wide range of colony structures, reproductive behaviours, queen and male lifespans, and habitat use. Reconstructing the evolutionary pathways of individual and social phenotypic traits suggests that the ancestral life history of Cardiocondyla was characterized by the presence of multiple, short-lived queens in small-sized colonies and a male polyphenism with winged dispersers and wingless fighters, which engage in lethal combat over female sexuals within their natal nests. Single queening, queen polyphenism, the loss of winged males and tolerance among wingless males appear to be derived traits that evolved with changes in nesting habits, colony size and the spread from tropical to seasonal environments. The aim of this review is to bring together the information on life-history evolution in Cardiocondyla and to highlight the suitability of this genus for functional genomic studies of adaptation, phenotypic plasticity, senescence, invasiveness and other key life-history traits of ants.

  1. Novelty and Innovation in the History of Life.

    PubMed

    Erwin, Douglas H

    2015-10-05

    The history of life as documented by the fossil record encompasses evolutionary diversifications at scales ranging from the Ediacaran-Cambrian explosion of animal life and the invasion of land by vascular plants, insects and vertebrates to the diversification of flowering plants over the past 100 million years and the radiation of horses. Morphological novelty and innovation has been a recurrent theme. The architects of the modern synthesis of evolutionary theory made three claims about evolutionary novelty and innovation: first, that all diversifications in the history of life represent adaptive radiations; second, that adaptive radiations are driven principally by ecological opportunity rather than by the supply of new morphological novelties, thus the primary questions about novelty and innovation focus on their ecological and evolutionary success; and third, that the rate of morphological divergence between taxa was more rapid early in the history of a clade but slowed over time as ecological opportunities declined. These claims have strongly influenced subsequent generations of evolutionary biologists, yet over the past two decades each has been challenged by data from the fossil record, by the results of comparative phylogenetic analyses and through insights from evolutionary developmental biology. Consequently a broader view of novelty and innovation is required. An outstanding issue for future work is identifying the circumstances associated with different styles of diversification and whether their frequency has changed through the history of life.

  2. Life-history plasticity in female threespine stickleback

    PubMed Central

    Baker, J A; Wund, M A; Heins, D C; King, R W; Reyes, M L; Foster, S A

    2015-01-01

    The postglacial adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus) has been widely used to investigate the roles of both adaptive evolution and plasticity in behavioral and morphological divergence from the ancestral condition represented by present-day oceanic stickleback. These phenotypes tend to exhibit high levels of ecotypic differentiation. Population divergence in life history has also been well studied, but in contrast to behavior and morphology, the extent and importance of plasticity has been much less well studied. In this review, we summarize what is known about life-history plasticity in female threespine stickleback, considering four traits intimately associated with reproductive output: age/size at maturation, level of reproductive effort, egg size and clutch size. We envision life-history plasticity in an iterative, ontogenetic framework, in which females may express plasticity repeatedly across each of several time frames. We contrast the results of laboratory and field studies because, for most traits, these approaches give somewhat different answers. We provide ideas on what the cues might be for observed plasticity in each trait and, when possible, we inquire about the relative costs and benefits to expressed plasticity. We end with an example of how we think plasticity may play out in stickleback life history given what we know of plasticity in the ancestor. PMID:26286665

  3. America: History and Life--A Wide Ranging Database.

    ERIC Educational Resources Information Center

    Sweetland, James H.

    1983-01-01

    Description of America: History and Life (AHL)--database including references from over 2,000 periodicals in literature, philosophy, religion, art, sociology, other disciplines of historical value--highlights structure; document treatment; access points; comparison of dissertation coverage between AHL and Comprehensive Dissertation Abstracts;…

  4. Temperature and kairomone induced life history plasticity in coexisting Daphnia

    USGS Publications Warehouse

    Bernot, R.J.; Dodds, W.K.; Quist, M.C.; Guy, C.S.

    2006-01-01

    We investigated the life history alterations of coexisting Daphnia species responding to environmental temperature and predator cues. In a laboratory experiment, we measured Daphnia life history plasticity under different predation risk and temperature treatments that simulate changing environmental conditions. Daphnia pulicaria abundance and size at first reproduction (SFR) declined, while ephippia (resting egg) formation increased at high temperatures. Daphnia mendotae abundance and clutch size increased with predation risk at high temperatures, but produced few ephippia. Thus, each species exhibited phenotypic plasticity, but responded in sharply different ways to the same environmental cues. In Glen Elder reservoir, Kansas USA, D. pulicaria dominance shifted to D. mendotae dominance as temperature and predation risk increased from March to June in both 1999 and 2000. Field estimates of life history shifts mirrored the laboratory experiment results, suggesting that similar phenotypic responses to seasonal cues contribute to seasonal Daphnia population trends. These results illustrate species-specific differences in life history plasticity among coexisting zooplankton taxa. ?? Springer-Verlag 2006.

  5. Life-history evolution in ants: the case of Cardiocondyla

    PubMed Central

    2017-01-01

    Ants are important components of most terrestrial habitats, and a better knowledge of the diversity of their life histories is essential to understand many aspects of ecosystem functioning. The myrmicine genus Cardiocondyla shows a wide range of colony structures, reproductive behaviours, queen and male lifespans, and habitat use. Reconstructing the evolutionary pathways of individual and social phenotypic traits suggests that the ancestral life history of Cardiocondyla was characterized by the presence of multiple, short-lived queens in small-sized colonies and a male polyphenism with winged dispersers and wingless fighters, which engage in lethal combat over female sexuals within their natal nests. Single queening, queen polyphenism, the loss of winged males and tolerance among wingless males appear to be derived traits that evolved with changes in nesting habits, colony size and the spread from tropical to seasonal environments. The aim of this review is to bring together the information on life-history evolution in Cardiocondyla and to highlight the suitability of this genus for functional genomic studies of adaptation, phenotypic plasticity, senescence, invasiveness and other key life-history traits of ants. PMID:28298341

  6. On the Psychometric Study of Human Life History Strategies.

    PubMed

    Richardson, George B; Sanning, Blair K; Lai, Mark H C; Copping, Lee T; Hardesty, Patrick H; Kruger, Daniel J

    2017-01-01

    This article attends to recent discussions of validity in psychometric research on human life history strategy (LHS), provides a constructive critique of the extant literature, and describes strategies for improving construct validity. To place the psychometric study of human LHS on more solid ground, our review indicates that researchers should (a) use approaches to psychometric modeling that are consistent with their philosophies of measurement, (b) confirm the dimensionality of life history indicators, and (c) establish measurement invariance for at least a subset of indicators. Because we see confirming the dimensionality of life history indicators as the next step toward placing the psychometrics of human LHS on more solid ground, we use nationally representative data and structural equation modeling to test the structure of middle adult life history indicators. We found statistically independent mating competition and Super-K dimensions and the effects of parental harshness and childhood unpredictability on Super-K were consistent with past research. However, childhood socioeconomic status had a moderate positive effect on mating competition and no effect on Super-K, while unpredictability did not predict mating competition. We conclude that human LHS is more complex than previously suggested-there does not seem to be a single dimension of human LHS among Western adults and the effects of environmental components seem to vary between mating competition and Super-K.

  7. Life Histories of Three Exemplary American Physical Educators

    ERIC Educational Resources Information Center

    Cazers, Gunars

    2009-01-01

    The purpose of the following article-style dissertation was to present the life histories of three exemplary physical educators, to give them voice, explore ways in which they experienced marginalization, and describe how they persevered in spite of difficulties they experienced in their careers. The participants included (a) Robin, a female…

  8. Patterns in life history traits of deep-water chondrichthyans

    NASA Astrophysics Data System (ADS)

    Rigby, Cassandra; Simpfendorfer, Colin A.

    2015-05-01

    Life history traits are important indicators of the productivity of species, and their ability to tolerate fishing pressure. Using a variety of life history traits (maximum size, size and age at maturity, longevity, growth rate, litter and birth size) we demonstrated differences in chondrichthyan life histories between shelf, pelagic and deep-water habitats and within the deep habitat down the continental slope and across geographic regions. Deep-water species had lower growth rates, later age at maturity, and higher longevity than both shelf and pelagic species. In the deep habitat, with increasing depth, species matured later, lived longer, had smaller litters and bred less frequently; regional differences in traits were also apparent. Deep-water species also had a smaller body size and the invariants of relative size and age at maturity were higher in deep water. The visual interaction hypothesis offers a potential explanation for these findings and it is apparent habitat influences the trade-offs in allocation of energy for survival and reproduction. Body size is not appropriate as a predictor of vulnerability in deep-water chondrichthyans and regional trait differences are possibly due to a fishing pressure response. Deep-water chondrichthyans are more vulnerable to exploitation than shelf and pelagic species and this vulnerability markedly increases with increasing depth. The life history traits of deep-water chondrichthyans are unique and reflect adaptations driven by both mortality and resource limitations of their habitat.

  9. Elevational covariation in environmental constraints and life histories of the desert lizard Sceloporus merriami

    SciTech Connect

    Grant, B.W. ); Dunham, A.E. )

    1990-10-01

    We examine environmental constraints on life history characters among three elevationally distinct populations of the desert lizard Sceloporus merriami in west Texas. We show how environmental gradients in temperature and food abundance interact to constrain body temperatures, daily activity times, growth rates, and age-specific body size. We suggest that these differences resulted in opposite responses from males and females with respect to their size and age at first reproduction. Results suggest an interaction between resource levels and biophysical constraints that may greatly influence differences among populations in important life history characteristics. Although these responses are hypothesized to be proximally induced by environmental constraints, the resulting life history differences in age-specific resource allocation to growth, storage, and reproduction may significantly affect fitness.

  10. Brains, teeth and life histories in hominins: a review.

    PubMed

    Bermúdez de Castro, José María; Modesto-Mata, Mario; Martinón-Torres, María

    2015-07-20

    The role of the brain in the somatic development, as well as in the establishment of the different variables of the life history pattern in vertebrates has been largely debated. Moreover, during the last thirty years, dental development has been used as a good proxy to infer different aspects of the life history in hominins, primarily due to the correlation that exists between age at first molar eruption and brain size in the order Primates. We review these questions using what is known about brain growth and maturation, dental development and life history pattern, mainly in Homo sapiens and Pan troglodytes. It has been assumed that the brain represents the pace-maker of our development. However, we consider that our particular phenotype is the result of a hierarchical genetic program modulated by epigenetic and environmental factors. The particular bauplan of any kind of organisms (e.g. primates) may explain the high correlation observed between different variables of its life history pattern, brain size or dental development. However, the correlation of these variables seems to be less reliable when dealing with low-rank taxonomical categories (i.e., species). We suggest that, while there is likely some relationship between the rate of somatic development and tooth development, our brain size and maturation (and, by extension, those of other species of the genus Homo) have derived towards a particular trajectory, with a unique pattern of prenatal and postnatal time and rate of growth and, particularly, with remarkable slow brain maturation. We suggest that extremely slow brain maturation could be a very recent acquisition of the last H. sapiens populations. Furthermore, our review of the literature suggests caution in drawing conclusions about aspects of the life history of the hominins from the information we can obtain from dental development in fossil specimens.

  11. The life history of Pleurogenoides orientalis (Srivastava, 1934) (Trematoda: Lecithodendriidae).

    PubMed

    Madhavi, R; Dhanumkumari, C; Ratnakumari, T B

    1987-01-01

    The life history of Pleurogenoides orientalis (Srivastava 1934), a lecithodendriid trematode of frogs in India is reported and stages in the life history are described. Natural infections with cercariae, which are virgulate xiphidiocercous type, were found in the prosobranch snail Alocinma travancorica. Metacercarial cysts were found in dragon-fly naiads (Tholymis tillarga and Tramea limbata) and aquatic bugs (Laccotrephes griseus and Ranatra elongata) collected from a stream. Adults occurred in the intestine of the pong frog, Rana cyanophlyctis. Laboratory reared A. travancorica fed with eggs of P. orientalis started shedding cercariae from 30 days post feeding. Development of cercariae into infective metacercariae in dragon-fly naiads took 18 days. Mature flukes were recovered from the intestine of experimentally infected R. cyanophlyctis. The entire life cycle from egg to egg producing adult takes 2 1/2 to 3 months.

  12. The origin of parental care in relation to male and female life history.

    PubMed

    Klug, Hope; Bonsall, Michael B; Alonzo, Suzanne H

    2013-04-01

    The evolution of maternal, paternal, and bi-parental care has been the focus of a great deal of research. Males and females vary in basic life-history characteristics (e.g., stage-specific mortality, maturation) in ways that are unrelated to parental investment. Surprisingly, few studies have examined the effect of this variation in male and female life history on the evolution of care. Here, we use a theoretical approach to determine the sex-specific life-history characteristics that give rise to the origin of paternal, maternal, or bi-parental care from an ancestral state of no care. Females initially invest more into each egg than males. Despite this inherent difference between the sexes, paternal, maternal, and bi-parental care are equally likely when males and females are otherwise similar. Thus, sex differences in initial zygotic investment do not explain the origin of one pattern of care over another. However, sex differences in adult mortality, egg maturation rate, and juvenile survival affect the pattern of care that will be most likely to evolve. Maternal care is more likely if female adult mortality is high, whereas paternal care is more likely if male adult mortality is high. These findings suggest that basic life-history differences between the sexes can alone explain the origin of maternal, paternal, and bi-parental care. As a result, the influence of life-history characteristics should be considered as a baseline scenario in studies examining the origin of care.

  13. Bringing history to life: simulating landmark experiments in psychology.

    PubMed

    Boynton, David M; Smith, Laurence D

    2006-05-01

    The course in history of psychology can be challenging for students, many of whom enter it with little background in history and faced with unfamiliar names and concepts. The sheer volume of material can encourage passive memorization unless efforts are made to increase student involvement. As part of a trend toward experiential history, historians of science have begun to supplement their lectures with demonstrations of classic physics experiments as a way to bring the history of science to life. Here, the authors report on computer simulations of five landmark experiments from early experimental psychology in the areas of reaction time, span of attention, and apparent motion. The simulations are designed not only to permit hands-on replication of historically important results but also to reproduce the experimental procedures closely enough that students can gain a feel for the nature of early research and the psychological processes being studied.

  14. Telling Modernization: Three Voices. Life History, Gender and the Discourse of Modernization. Roskilde University Life History Project Paper.

    ERIC Educational Resources Information Center

    Anderson, Linda

    The relationship between life history, gender, and the discourse of modernization was examined from the perspective of a researcher with extensive experience performing evaluations about modernization within human services in Denmark. Three stories about site-based management in two human service institutionsa youth center and a boarding school…

  15. Phylogeny and life histories of the 'Insectivora': controversies and consequences.

    PubMed

    Symonds, Matthew R E

    2005-02-01

    The evolutionary relationships of the eutherian order Insectivora (Lipotyphla sensu stricto) are the subject of considerable debate. The difficulties in establishing insectivore phylogeny stem from their lack of many shared derived characteristics. The grouping is therefore something of a 'wastebasket' taxon. Most of the older estimates of phylogeny, based on morphological evidence, assumed insectivore monophyly. More recently, molecular phylogenies argue strongly against monophyly, although they differ in the extent of polyphyly inferred for the order. I review the history of insectivore phylogenetics and systematics, focussing on the relationships between the six extant families (Erinaceidae--hedgehogs and moonrats, Talpidae - moles and desmans, Soricidae - shrews, Solenodontidae--solenodons, Tenrecidae--tenrecs and otter-shrews and Chrysochloridae--golden moles). I then examine how these various phylogenetic hypotheses influence the results of comparative analyses and our interpretation of insectivore life-history evolution. I assess which particular controversies have the greatest effect on results, and discuss the implications for comparative analyses where the phylogeny is controversial. I also explore and suggest explanations for certain insectivore life-history trends: increased gestation length and litter size in tenrecs, increased encephalization in moles, and the mixed fast and slow life-history strategies in solenodons. Finally, I consider the implications for comparative analyses of the recent strongly supported phylogenetic hypothesis of an endemic African clade of mammals that includes the insectivore families of tenrecs and golden moles.

  16. Life histories predict vulnerability to overexploitation in parrotfishes

    NASA Astrophysics Data System (ADS)

    Taylor, Brett M.; Houk, Peter; Russ, Garry R.; Choat, J. Howard

    2014-12-01

    A scarcity of life-history data currently exists for many exploited coral reef fishes, hindering our ability to interpret fishery dynamics and develop sound conservation policies. In particular, parrotfishes (Family Labridae) represent a ubiquitous and ecologically important group that is increasingly prevalent in commercial and artisanal fisheries worldwide. We used both fishery-dependent and fishery-independent data to examine the effect of life histories on vulnerability to overexploitation in parrotfishes. Vulnerability for each species was derived from independent measures associated with both temporal (20-year catch records) and spatial datasets. Most life-history traits examined were significant predictors of vulnerability across species, but their relative utility differed considerably. Length-based traits (e.g., lengths at maturity and sex change, maximum length) were generally superior to age-based traits (e.g., life span), but one age-based trait, age at female maturation, was the best predictor. The results suggest that easily derived metrics such as maximum length can be effective measures of sensitivity to exploitation when applied to phylogenetically related multispecies assemblages, but more holistic and comprehensive age-based demographic data should be sought, especially in data-deficient and heavily impacted regions. Given the increasing prevalence of parrotfishes in the global coral reef harvest, species-specific responses demonstrate the capacity for heavy fishing pressure to alter parrotfish assemblages considerably.

  17. Fast-slow continuum and reproductive strategies structure plant life-history variation worldwide.

    PubMed

    Salguero-Gómez, Roberto; Jones, Owen R; Jongejans, Eelke; Blomberg, Simon P; Hodgson, David J; Mbeau-Ache, Cyril; Zuidema, Pieter A; de Kroon, Hans; Buckley, Yvonne M

    2016-01-05

    The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population performance. We show that 55% of the variation in plant life-history strategies is adequately characterized using two independent axes: the fast-slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other. Our findings remain consistent across major habitats and are minimally affected by plant growth form and phylogenetic ancestry, suggesting that the relative independence of the fast-slow and reproduction strategy axes is general in the plant kingdom. Our findings have similarities with how life-history strategies are structured in mammals, birds, and reptiles. The position of plant species populations in the 2D space produced by both axes predicts their rate of recovery from disturbances and population growth rate. This life-history framework may complement trait-based frameworks on leaf and wood economics; together these frameworks may allow prediction of responses of plants to anthropogenic disturbances and changing environments.

  18. Fast–slow continuum and reproductive strategies structure plant life-history variation worldwide

    PubMed Central

    Salguero-Gómez, Roberto; Jones, Owen R.; Jongejans, Eelke; Blomberg, Simon P.; Hodgson, David J.; Mbeau-Ache, Cyril; Zuidema, Pieter A.; de Kroon, Hans; Buckley, Yvonne M.

    2016-01-01

    The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population performance. We show that 55% of the variation in plant life-history strategies is adequately characterized using two independent axes: the fast–slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other. Our findings remain consistent across major habitats and are minimally affected by plant growth form and phylogenetic ancestry, suggesting that the relative independence of the fast–slow and reproduction strategy axes is general in the plant kingdom. Our findings have similarities with how life-history strategies are structured in mammals, birds, and reptiles. The position of plant species populations in the 2D space produced by both axes predicts their rate of recovery from disturbances and population growth rate. This life-history framework may complement trait-based frameworks on leaf and wood economics; together these frameworks may allow prediction of responses of plants to anthropogenic disturbances and changing environments. PMID:26699477

  19. Unravelling the life history of Amazonian fishes through otolith microchemistry

    PubMed Central

    Hermann, Theodore W.; Stewart, Donald J.; Limburg, Karin E.; Castello, Leandro

    2016-01-01

    Amazonian fishes employ diverse migratory strategies, but the details of these behaviours remain poorly studied despite numerous environmental threats and heavy commercial exploitation of many species. Otolith microchemistry offers a practical, cost-effective means of studying fish life history in such a system. This study employed a multi-method, multi-elemental approach to elucidate the migrations of five Amazonian fishes: two ‘sedentary’ species (Arapaima sp. and Plagioscion squamosissimus), one ‘floodplain migrant’ (Prochilodus nigricans) and two long-distance migratory catfishes (Brachyplatystoma rousseauxii and B. filamentosum). The Sr : Ca and Zn : Ca patterns in Arapaima were consistent with its previously observed sedentary life history, whereas Sr : Ca and Mn : Ca indicated that Plagioscion may migrate among multiple, chemically distinct environments during different life-history stages. Mn : Ca was found to be potentially useful as a marker for identifying Prochilodus's transition from its nursery habitats into black water. Sr : Ca and Ba : Ca suggested that B. rousseauxii resided in the Amazon estuary for the first 1.5–2 years of life, shown by the simultaneous increase/decrease of otolith Sr : Ca/Ba : Ca, respectively. Our results further suggested that B. filamentosum did not enter the estuary during its life history. These results introduce what should be a productive line of research desperately needed to better understand the migrations of these unique and imperilled fishes. PMID:27429777

  20. When mothers need others: The impact of hominin life history evolution on cooperative breeding.

    PubMed

    Kramer, Karen L; Otárola-Castillo, Erik

    2015-07-01

    The evolution of cooperative breeding is particularly complex in humans because many other traits that directly affect parental care (shorter birth intervals, increased offspring survivorship, juvenile dependence, and older ages at dispersal) also emerge during the Pleistocene. If human cooperative breeding is ancient, it likely evolved in a hominin lacking a fully modern life history. However, the impact that changing life history traits has on parental care and cooperative breeding has not been analytically investigated. We develop an exploratory model to simulate an economic problem that would have arisen over the course of hominin life history evolution to identify those transitions that produced the strongest pressures for cooperative childrearing. The model generates two central predictions. First, help within maternal-offspring groups can support early changes in juvenile dependence, dispersal age, birth intervals, and fertility. If so, maternal-juvenile cooperation may be an important but understudied step in the evolution of human cooperative breeding. Second, pressure to recruit adult cooperation is most pronounced under more derived conditions of late dispersal and later ages of juvenile dependence, with a strong interaction at short birth intervals. Our findings indicate that changes in life history traits that affect parental care are critical in considering background selective forces that shaped the evolution of cooperative breeding.

  1. Life histories and the evolution of cooperative breeding in mammals.

    PubMed

    Lukas, Dieter; Clutton-Brock, Tim

    2012-10-07

    While the evolution of cooperative breeding systems (where non-breeding helpers participate in rearing young produced by dominant females) has been restricted to lineages with socially monogamous mating systems where coefficients of relatedness between group members are usually high, not all monogamous lineages have produced species with cooperative breeding systems, suggesting that other factors constrain the evolution of cooperative breeding. Previous studies have suggested that life-history parameters, including longevity, may constrain the evolution of cooperative breeding. Here, we show that transitions to cooperative breeding across the mammalian phylogeny have been restricted to lineages where females produce multiple offspring per birth. We find no support for effects of longevity or of other life-history parameters. We suggest that the evolution of cooperative breeding has been restricted to monogamous lineages where helpers have the potential to increase the reproductive output of breeders.

  2. The life-history basis of behavioural innovations.

    PubMed

    Sol, Daniel; Sayol, Ferran; Ducatez, Simon; Lefebvre, Louis

    2016-03-19

    The evolutionary origin of innovativeness remains puzzling because innovating means responding to novel or unusual problems and hence is unlikely to be selected by itself. A plausible alternative is considering innovativeness as a co-opted product of traits that have evolved for other functions yet together predispose individuals to solve problems by adopting novel behaviours. However, this raises the question of why these adaptations should evolve together in an animal. Here, we develop the argument that the adaptations enabling animals to innovate evolve together because they are jointly part of a life-history strategy for coping with environmental changes. In support of this claim, we present comparative evidence showing that in birds, (i) innovative propensity is linked to life histories that prioritize future over current reproduction, (ii) the link is in part explained by differences in brain size, and (iii) innovative propensity and life-history traits may evolve together in generalist species that frequently expose themselves to novel or unusual conditions. Combined with previous evidence, these findings suggest that innovativeness is not a specialized adaptation but more likely part of a broader general adaptive system to cope with changes in the environment.

  3. The life-history basis of behavioural innovations

    PubMed Central

    Sol, Daniel; Sayol, Ferran; Ducatez, Simon; Lefebvre, Louis

    2016-01-01

    The evolutionary origin of innovativeness remains puzzling because innovating means responding to novel or unusual problems and hence is unlikely to be selected by itself. A plausible alternative is considering innovativeness as a co-opted product of traits that have evolved for other functions yet together predispose individuals to solve problems by adopting novel behaviours. However, this raises the question of why these adaptations should evolve together in an animal. Here, we develop the argument that the adaptations enabling animals to innovate evolve together because they are jointly part of a life-history strategy for coping with environmental changes. In support of this claim, we present comparative evidence showing that in birds, (i) innovative propensity is linked to life histories that prioritize future over current reproduction, (ii) the link is in part explained by differences in brain size, and (iii) innovative propensity and life-history traits may evolve together in generalist species that frequently expose themselves to novel or unusual conditions. Combined with previous evidence, these findings suggest that innovativeness is not a specialized adaptation but more likely part of a broader general adaptive system to cope with changes in the environment. PMID:26926277

  4. Brain ontogeny and life history in Pleistocene hominins

    PubMed Central

    Hublin, Jean-Jacques; Neubauer, Simon; Gunz, Philipp

    2015-01-01

    A high level of encephalization is critical to the human adaptive niche and emerged among hominins over the course of the past 2 Myr. Evolving larger brains required important adaptive adjustments, in particular regarding energy allocation and life history. These adaptations included a relatively small brain at birth and a protracted growth of highly dependent offspring within a complex social environment. In turn, the extended period of growth and delayed maturation of the brain structures of humans contribute to their cognitive complexity. The current palaeoanthropological evidence shows that, regarding life history and brain ontogeny, the Pleistocene hominin taxa display different patterns and that one cannot simply contrast an ‘ape-model’ to a ‘human-model’. Large-brained hominins such as Upper Pleistocene Neandertals have evolved along their own evolutionary pathway and can be distinguished from modern humans in terms of growth pattern and brain development. The life-history pattern and brain ontogeny of extant humans emerged only recently in the course of human evolution. PMID:25602066

  5. Interrelationships among life-history traits in three California oaks.

    PubMed

    Barringer, Brian C; Koenig, Walter D; Knops, Johannes M H

    2013-01-01

    Life-history traits interact in important ways. Relatively few studies, however, have explored the relationships between life-history traits in long-lived taxa such as trees. We examined patterns of energy allocation to components of reproduction and growth in three species of California oaks (Quercus spp.) using a combination of annual acorn censuses, dendrometer bands to measure radial increment, and litterfall traps. Our results are generally consistent with the hypothesis that energy invested in reproduction detracts from the amount of energy available for growth in these long-lived taxa; i.e., there are trade-offs between these traits. The relationships between reproduction and growth varied substantially among specific trait combinations and tree species, however, and in some cases were in the direction opposite that expected based on the assumption of trade-offs between them. This latter finding appears to be a consequence of the pattern of resource use across years in these long-lived trees contrasting with the expected partitioning of resource use within years in short-lived taxa. Thus, the existence and magnitude of putative trade-offs varied depending on whether the time scale considered was within or across years. Collectively, our results indicate that negative relationships between fundamental life-history traits can be important at multiple levels of modular organization and that energy invested in reproduction can have measurable consequences in terms of the amount of energy available for future reproduction and both current and future growth.

  6. The contribution of developmental experience vs. condition to life history, trait variation and individual differences.

    PubMed

    DiRienzo, Nicholas; Montiglio, Pierre-Olivier

    2016-07-01

    1. Developmental experience, for example food abundance during juvenile stages, is known to affect life history and behaviour. However, the life history and behavioural consequences of developmental experience have rarely been studied in concert. As a result, it is still unclear whether developmental experience affects behaviour through changes in life history, or independently of it. 2. The effect of developmental experience on life history and behaviour may also be masked or affected by individual condition during adulthood. Thus, it is critical to tease apart the effects of developmental experience and current individual condition on life history and behaviour. 3. In this study, we manipulated food abundance during development in the western black widow spider, Latrodectus hesperus, by rearing spiders on either a restricted or ad lib diet. We separated developmental from condition-dependent effects by assaying adult foraging behaviour (tendency to attack prey and to stay on out of the refuge following an attack) and web structure multiple times under different levels of satiation following different developmental treatments. 4. Spiders reared under food restriction matured slower and at a smaller size than spiders reared in ad lib conditions. Spiders reared on a restricted diet were more aggressive towards prey and built webs structured for prey capture, while spiders reared on an ad lib diet were less aggressive and built safer webs. Developmental treatment affected which traits were plastic as adults: restricted spiders built safer webs when their adult condition increased, while ad lib spiders reduced their aggression when their adult condition increased. The amount of individual variation in behaviour and web structure varied with developmental treatment. Spiders reared on a restricted diet exhibited consistent variation in all aspects of foraging behaviour and web structure, while spiders reared on an ad lib diet exhibited consistent individual variation in

  7. A review of Ruffe (Gymnocephalus cernuus) life history in its ...

    EPA Pesticide Factsheets

    Ruffe (Gymnocephalus cernuus) have caused and have the potential to cause great ecological damage as invasive species in North America, parts of the European Union, Scandinavian countries, and the United Kingdom. The objectives of this review are to define the Ruffe's native and non-native range, examine the life history requirements of Ruffe, explore the Ruffe life cycle, and differentiate between the life stages. We compare Ruffe in their native range to Ruffe in their non-native range to determine if there are any differences in habitat, size, age, genotype, or migratory patterns in the winter. Literature from both the native and non-native ranges of Ruffe, with a particular emphasis on rare translated literature, is used. Ruffe have variability and plasticity in their chemical, physical, biological, and habitat requirements in their native and non-native ranges. Adult Ruffe have a suite of characteristics that make them adaptable to novel environments, including age and size at maturity, maximum age and length (and/ or weight), reproduction type, genotype, feeding habits, seasonal movements, and spawning movements. There is variability among these characteristics seen between the Ruffe's native, non-native North American, and European non-native populations. Based on the Ruffe's variable life history strategies and their recent range expansion, all of the Great Lakes and many other regions in the U.K., Europe, and Scandinavian countries could be vulnerable t

  8. The Surprising History of Claims for Life on the Sun

    NASA Astrophysics Data System (ADS)

    Crowe, Michael J.

    2011-11-01

    Because astronomers are now convinced that it is impossible for life, especially intelligent life, to exist on the Sun and stars, it might be assumed that astronomers have always held this view. This paper shows that throughout most of the history of astronomy, some intellectuals, including a number of well-known astronomers, have advocated the existence of intelligent life on our Sun and thereby on stars. Among the more prominent figures discussed are Nicolas of Cusa, Giordano Bruno, William Whiston, Johann Bode, Roger Boscovich, William Herschel, Auguste Comte, Carl Gauss, Thomas Dick, John Herschel, and François Arago. One point in preparing this paper is to show differences between the astronomy of the past and that of the present.

  9. Understanding life together: a brief history of collaboration in biology.

    PubMed

    Vermeulen, Niki; Parker, John N; Penders, Bart

    2013-09-01

    The history of science shows a shift from single-investigator 'little science' to increasingly large, expensive, multinational, interdisciplinary and interdependent 'big science'. In physics and allied fields this shift has been well documented, but the rise of collaboration in the life sciences and its effect on scientific work and knowledge has received little attention. Research in biology exhibits different historical trajectories and organisation of collaboration in field and laboratory - differences still visible in contemporary collaborations such as the Census of Marine Life and the Human Genome Project. We employ these case studies as strategic exemplars, supplemented with existing research on collaboration in biology, to expose the different motives, organisational forms and social dynamics underpinning contemporary large-scale collaborations in biology and their relations to historical patterns of collaboration in the life sciences. We find the interaction between research subject, research approach as well as research organisation influencing collaboration patterns and the work of scientists.

  10. Understanding life together: A brief history of collaboration in biology

    PubMed Central

    Vermeulen, Niki; Parker, John N.; Penders, Bart

    2013-01-01

    The history of science shows a shift from single-investigator ‘little science’ to increasingly large, expensive, multinational, interdisciplinary and interdependent ‘big science’. In physics and allied fields this shift has been well documented, but the rise of collaboration in the life sciences and its effect on scientific work and knowledge has received little attention. Research in biology exhibits different historical trajectories and organisation of collaboration in field and laboratory – differences still visible in contemporary collaborations such as the Census of Marine Life and the Human Genome Project. We employ these case studies as strategic exemplars, supplemented with existing research on collaboration in biology, to expose the different motives, organisational forms and social dynamics underpinning contemporary large-scale collaborations in biology and their relations to historical patterns of collaboration in the life sciences. We find the interaction between research subject, research approach as well as research organisation influencing collaboration patterns and the work of scientists. PMID:23578694

  11. Biologic History and the Cardinal Rule of Life

    NASA Astrophysics Data System (ADS)

    Schopf, J. W.

    2004-12-01

    In broad perspective, the history of life is remarkably static -- once set, a system that has changed little over all of geological time. The basic chemistry of living systems (CHONSP, and the monomers and polymers they compose), the genetics and cellular structure of life, even the ecologic division of the biologic world into "eaters" (heterotrophs) and "eatees" (autotrophs), are innovations all dating from the Archean that have carried over to the present. Throughout Earth history, biology has followed the Cardinal Rule of Life -- avoid change, never evolve at all! Biology maintains the status quo, opportunistically responding only if conditions change. Life's credo might well be "if it ain't broken, don't fix it." Of course, biomolecules do get "broken," by mutations, but living systems have many biochemical repair mechanisms. Evolution is a result of small changes that slip through unfixed. We see the results of evolution in the fossil record only because of the vastness, the true enormity, of geological time. What events punctuated this static underpinning to produce the modern living world? Only three, each in its own way shaping the course of life's history. The earliest, photosynthesis, freed life from dependence on foodstuffs made by nonbiologic processes. The advent of the advanced form of this process, oxygenic ("green plant") photosynthesis -- also an Archean innovation -- pumped oxygen into the environment (markedly increasing energy yields), "rusted the Earth" (evidenced by banded iron-formations), and, by ˜2,300 Ma ago, led to establishment of an aerobic-anaerobic ecosystem like that today. Not surprisingly, given the Cardinal Rule of Life, the inventors of this innovation, microbial cyanobacteria, evolved little over billions of years. The second major innovation was sex. In the modern world, this reproductive process is exhibited only by nucleated (eukaryotic) cells, derived from non-sexual eukaryotic ancestors. Although eukaryotes date from ˜2

  12. Survival on the ark: life history trends in captive parrots

    PubMed Central

    Young, Anna M.; Hobson, Elizabeth A.; Lackey, Laurie Bingaman; Wright, Timothy F.

    2011-01-01

    Members of the order Psittaciformes (parrots and cockatoos) are among the most long-lived and endangered avian species. Comprehensive data on lifespan and breeding are critical to setting conservation priorities, parameterizing population viability models, and managing captive and wild populations. To meet these needs, we analyzed 83, 212 life history records of captive birds from the International Species Information System and calculated lifespan and breeding parameters for 260 species of parrots (71% of extant species). Species varied widely in lifespan, with larger species generally living longer than smaller ones. The highest maximum lifespan recorded was 92 years in Cacatua moluccensis, but only 11 other species had a maximum lifespan over 50 years. Our data indicate that while some captive individuals are capable of reaching extraordinary ages, median lifespans are generally shorter than widely assumed, albeit with some increase seen in birds presently held in zoos. Species that lived longer and bred later in life tended to be more threatened according to IUCN classifications. We documented several individuals of multiple species that were able to breed for more than two decades, but the majority of clades examined had much shorter active reproduction periods. Post-breeding periods were surprisingly long and in many cases surpassed the duration of active breeding. Our results demonstrate the value of the ISIS database to estimate life history data for an at-risk taxon that is difficult to study in the wild, and provide life history data that is crucial for predictive modeling of future species endangerment and proactively managing captive populations of parrots. PMID:22389582

  13. The history of life and death: a 'spiritual' history from invisible matter to prolongation of life.

    PubMed

    Gemelli, Benedino

    2012-01-01

    Over a long period of time, particularly from the nineteenth century on, Francis Bacon's philosophy has been interpreted as centred on the Novum organum and focused on the role that a well-organized method may play in securing a reliable knowledge of nature. In fact, if we examine Bacon's oeuvre as a whole, including some recent manuscript findings (De vijs mortis), we can safely argue that the issues addressed in the Novum organum represent only a part of Bacon's agenda, and not even the most important ones. By contrast, it is apparent that, from the very beginning of his investigations, he emphasized the central role of medicine, the need to establish new approaches in the study of the vital functions and the importance of promoting new discoveries in the medical field, not so much to find a cure for the many illnesses that plagued mankind as to prolong human life. In this sense, Historia vitae et mortis plays a central role in Bacon's programme to extend human knowledge and power, for, in his opinion, human beings could recover their lost ability to live a long and healthy life by embarking on careful investigations of nature. Far from being a purely descriptive or abstract exercise, Bacon's historia can therefore be seen as an operative tool to attain some of mankind's basic aims.

  14. Modeling tradeoffs in avian life history traits and consequences for population growth

    USGS Publications Warehouse

    Clark, M.E.; Martin, T.E.

    2007-01-01

    Variation in population dynamics is inherently related to life history characteristics of species, which vary markedly even within phylogenetic groups such as passerine birds. We computed the finite rate of population change (??) from a matrix projection model and from mark-recapture observations for 23 bird species breeding in northern Arizona. We used sensitivity analyses and a simulation model to separate contributions of different life history traits to population growth rate. In particular we focused on contrasting effects of components of reproduction (nest success, clutch size, number of clutches, and juvenile survival) versus adult survival on ??. We explored how changes in nest success or adult survival coupled to costs in other life history parameters affected ?? over a life history gradient provided by our 23 Arizona species, as well as a broader sample of 121 North American passerine species. We further examined these effects for more than 200 passeriform and piciform populations breeding across North America. Model simulations indicate nest success and juvenile survival exert the largest effects on population growth in species with moderate to high reproductive output, whereas adult survival contributed more to population growth in long-lived species. Our simulations suggest that monitoring breeding success in populations across a broad geographic area provides an important index for identifying neotropical migratory populations at risk of serious population declines and a potential method for identifying large-scale mechanisms regulating population dynamics. ?? 2007 Elsevier B.V. All rights reserved.

  15. Egg Size Effects across Multiple Life-History Stages in the Marine Annelid Hydroides diramphus

    PubMed Central

    Allen, Richard M.; Marshall, Dustin

    2014-01-01

    The optimal balance of reproductive effort between offspring size and number depends on the fitness of offspring size in a particular environment. The variable environments offspring experience, both among and within life-history stages, are likely to alter the offspring size/fitness relationship and favor different offspring sizes. Hence, the many environments experienced throughout complex life-histories present mothers with a significant challenge to optimally allocate their reproductive effort. In a marine annelid, we tested the relationship between egg size and performance across multiple life-history stages, including: fertilization, larval development, and post-metamorphosis survival and size in the field. We found evidence of conflicting effects of egg size on performance: larger eggs had higher fertilization under sperm-limited conditions, were slightly faster to develop pre-feeding, and were larger post-metamorphosis; however, smaller eggs had higher fertilization when sperm was abundant, and faster planktonic development; and egg size did not affect post-metamorphic survival. The results indicate that egg size effects are conflicting in H. diramphus depending on the environments within and among life-history stages. We suggest that offspring size in this species may be a compromise between the overall costs and benefits of egg sizes in each stage and that performance in any one stage is not maximized. PMID:25036850

  16. The influence of diurnal temperature variation on degree-day accumulation and insect life history.

    PubMed

    Chen, Shi; Fleischer, Shelby J; Saunders, Michael C; Thomas, Matthew B

    2015-01-01

    Ectotherms, such as insects, experience non-constant temperatures in nature. Daily mean temperatures can be derived from the daily maximum and minimum temperatures. However, the converse is not true and environments with the same mean temperature can exhibit very different diurnal temperate ranges. Here we apply a degree-day model for development of the grape berry moth (Paralobesia viteana, a significant vineyard pest in the northeastern USA) to investigate how different diurnal temperature range conditions can influence degree-day accumulation and, hence, insect life history. We first consider changes in diurnal temperature range independent of changes in mean temperatures. We then investigate grape berry moth life history under potential climate change conditions, increasing mean temperature via variable patterns of change to diurnal temperature range. We predict that diurnal temperature range change can substantially alter insect life history. Altering diurnal temperature range independent of the mean temperature can affect development rate and voltinism, with the magnitude of the effects dependent on whether changes occur to the daily minimum temperature (Tmin), daily maximum temperature (Tmax), or both. Allowing for an increase in mean temperature produces more marked effects on life history but, again, the patterns and magnitude depend on the nature of the change to diurnal temperature range together with the starting conditions in the local environment. The study highlights the importance of characterizing the influence of diurnal temperature range in addition to mean temperature alone.

  17. Gene flow in Antarctic fishes: the role of oceanography and life history

    NASA Astrophysics Data System (ADS)

    Young, Emma; Rock, Jenny; Carvalho, Gary; Murphy, Eugene; Meredith, Michael; Hutchinson, Bill

    2010-05-01

    Marine organisms with pelagic larvae are generally assumed to experience high gene flow and low levels of population differentiation. However, variability in life history and environmental characteristics, in particular oceanographic flow fields, can significantly influence dispersal, and their relative effects are frequently unclear. Our research examines the influence of oceanographic and life history variability on gene flow in two species of Antarctic fish: Champsocephalus gunnari and Notothenia rossii. These species are broadly sympatric in their distribution, but differ in aspects of life history that are expected to strongly affect their dispersal capabilities. Our research has used two complementary techniques. Genetic analyses, specifically mtDNA and microsatellite markers, have been used to examine historic and contemporary gene flow and thus describe patterns of population differentiation at the circumpolar scale. These analyses have been compared with predicted larval transport from a global oceanographic model (OCCAM) combined with individual based particle tracking models. In using these complementary techniques, the relative influences of early life history and oceanographic variability can be elucidated. Here we present the key findings of our research, including evidence for inter-specific variation in mitochondrial gene flow at the circumpolar level and a limited degree of genetic structuring within the Scotia Sea.

  18. Effect of metal stress on life history divergence and quantitative genetic architecture in a wolf spider.

    PubMed

    Hendrickx, F; Maelfait, J-P; Lens, L

    2008-01-01

    Effects and consequences of stress exposure on life history strategies and quantitative genetic variation in wild populations remain poorly understood. We here study whether long-term exposure to heavy metal pollution may result in alternative life history strategies and alter quantitative genetic properties in natural populations of the wolf spider Pirata piraticus. Offspring originating from a reference and a metal contaminated population and their reciprocal hybrid cross were bred in a half-sib mating scheme and subsequently reared in cadmium contaminated vs. clean environment. Results from this experiment provided evidence for a genetically based reduced growth rate and increased egg size in the contaminated population. Growth rate reduction in response to cadmium contamination was only observed for the reference population. Animal model analysis revealed that heritability for growth rate was large for the reference population under reference conditions, but much lower under metal stressed conditions, caused by a strong decrease in additive genetic variance. Heritability for growth of the metal contaminated population was very low, even under reference conditions. Initial size of the offspring was primarily determined by maternal effects, whereas egg size produced by the offspring was determined by both sire and dam effects, indicating that egg size determination is under control of the female genotype. In conclusion, these results show that metal stress can not only affect life history variation in natural populations, but also decreases the expression as well as the of the amount of genetic variation for particular life history traits.

  19. Life history trade-offs and relaxed selection can decrease bacterial virulence in environmental reservoirs.

    PubMed

    Mikonranta, Lauri; Friman, Ville-Petri; Laakso, Jouni

    2012-01-01

    Pathogen virulence is usually thought to evolve in reciprocal selection with the host. While this might be true for obligate pathogens, the life histories of opportunistic pathogens typically alternate between within-host and outside-host environments during the infection-transmission cycle. As a result, opportunistic pathogens are likely to experience conflicting selection pressures across different environments, and this could affect their virulence through life-history trait correlations. We studied these correlations experimentally by exposing an opportunistic bacterial pathogen Serratia marcescens to its natural protist predator Tetrahymena thermophila for 13 weeks, after which we measured changes in bacterial traits related to both anti-predator defence and virulence. We found that anti-predator adaptation (producing predator-resistant biofilm) caused a correlative attenuation in virulence. Even though the direct mechanism was not found, reduction in virulence was most clearly connected to a predator-driven loss of a red bacterial pigment, prodigiosin. Moreover, life-history trait evolution was more divergent among replicate populations in the absence of predation, leading also to lowered virulence in some of the 'predator absent' selection lines. Together these findings suggest that the virulence of non-obligatory, opportunistic bacterial pathogens can decrease in environmental reservoirs through life history trade-offs, or random accumulation of mutations that impair virulence traits under relaxed selection.

  20. Modelling the sensitivity of life history traits to climate change in a temporary pool crustacean.

    PubMed

    Pinceel, Tom; Vanschoenwinkel, Bram; Brendonck, Luc; Buschke, Falko

    2016-07-11

    Temporary pool inhabitants face altered inundation regimes under climate change. While their exposure to these changes has received considerable attention, few studies have investigated their sensitivity or adaptability. Here, we use zooplankton as a model to explore how decreasing hydroperiods affect extinction risks and assess whether changes in life history traits could promote persistence. For this, we construct a three-stage matrix population model parameterised with realistic life-history values for the fairy shrimp Branchipodopsis wolfi from pools with varying hydroperiods. Our results suggest that extinction risks increase drastically once the median hydroperiod drops below a critical threshold. Although changes in life-history parameters could potentially compensate for this risk, the relative importance of each trait for population growth depends on the median hydroperiod. For example, survival of dormant eggs seemed to be most important when hydroperiods were short while the survival of freshly laid eggs and adult individuals were more important in longer-lived pools. Overall, this study demonstrates that zooplankton species are sensitive to climate change and that the adaptive capacity of organisms from temporary pools with dissimilar hydrology hinges on selection of different life history traits.

  1. The roles of life-history selection and sexual selection in the adaptive evolution of mating behavior in a beetle.

    PubMed

    Maklakov, Alexei A; Cayetano, Luis; Brooks, Robert C; Bonduriansky, Russell

    2010-05-01

    Although there is continuing debate about whether sexual selection promotes or impedes adaptation to novel environments, the role of mating behavior in such adaptation remains largely unexplored. We investigated the evolution of mating behavior (latency to mating, mating probability and duration) in replicate populations of seed beetles Callosobruchus maculatus subjected to selection on life-history ("Young" vs. "Old" reproduction) under contrasting regimes of sexual selection ("Monogamy" vs. "Polygamy"). Life-history selection is predicted to favor delayed mating in "Old" females, but sexual conflict under polygamy can potentially retard adaptive life-history evolution. We found that life-history selection yielded the predicted changes in mating behavior, but sexual selection regime had no net effect. In within-line crosses, populations selected for late reproduction showed equally reduced early-life mating probability regardless of mating system. In between-line crosses, however, the effect of life-history selection on early-life mating probability was stronger in polygamous lines than in monogamous ones. Thus, although mating system influenced male-female coevolution, removal of sexual selection did not affect the adaptive evolution of mating behavior. Importantly, our study shows that the interaction between sexual selection and life-history selection can result in either increased or decreased reproductive divergence depending on the ecological context.

  2. Early-Life Characteristics, Psychiatric History, and Cognition Trajectories in Later Life

    ERIC Educational Resources Information Center

    Brown, Maria Teresa

    2010-01-01

    Purpose of the Study: Although considerable attention has been paid to the relationship between later-life depression and cognitive function, the relationship between a history of psychiatric problems and cognitive function is not very well documented. Few studies of relationships between childhood health, childhood disadvantage, and cognitive…

  3. Life history and the evolution of parental care.

    PubMed

    Klug, Hope; Bonsall, Michael B

    2010-03-01

    Patterns of parental care are strikingly diverse in nature, and parental care is thought to have evolved repeatedly multiple times. Surprisingly, relatively little is known about the most general conditions that lead to the origin of parental care. Here, we use a theoretical approach to explore the basic life-history conditions (i.e., stage-specific mortality and maturation rates, reproductive rates) that are most likely to favor the evolution of some form of parental care from a state of no care. We focus on parental care of eggs and eggs and juveniles and consider varying magnitudes of the benefits of care. Our results suggest that parental care can evolve under a range of life-history conditions, but in general will be most strongly favored when egg death rate in the absence of care is high, juvenile survival in the absence of care is low (for the scenario in which care extends into the juvenile stage), adult death rate is relatively high, egg maturation rate is low, and the duration of the juvenile stage is relatively short. Additionally, parental care has the potential to be favored at a broad range of adult reproductive rates. The relative importance of these life-history conditions in favoring or limiting the evolution of care depends on the magnitude of the benefits of care, the relationship between initial egg allocation and subsequent offspring survival, and whether care extends into the juvenile stage. The results of our model provide a general set of predictions regarding when we would expect parental care to evolve from a state of no care, and in conjunction with other work on the topic, will enhance our understanding of the evolutionary dynamics of parental care and facilitate comparative analyses.

  4. Corticosterone, testosterone and life-history strategies of birds.

    PubMed

    Hau, Michaela; Ricklefs, Robert E; Wikelski, Martin; Lee, Kelly A; Brawn, Jeffrey D

    2010-10-22

    Steroid hormones have similar functions across vertebrates, but circulating concentrations can vary dramatically among species. We examined the hypothesis that variation in titres of corticosterone (Cort) and testosterone (T) is related to life-history traits of avian species. We predicted that Cort would reach higher levels under stress in species with higher annual adult survival rates since Cort is thought to promote physiological and behavioural responses that reduce risk to the individual. Conversely, we predicted that peak T during the breeding season would be higher in short-lived species with high mating effort as this hormone is known to promote male fecundity traits. We quantified circulating hormone concentrations and key life-history traits (annual adult survival rate, breeding season length, body mass) in males of free-living bird species during the breeding season at a temperate site (northern USA) and a tropical site (central Panama). We analysed our original data by themselves, and also combined with published data on passerine birds to enhance sample size. In both approaches, variation in baseline Cort (Cort0) among species was inversely related to breeding season length and body mass. Stress-induced corticosterone (MaxCort) also varied inversely with body mass and, as predicted, also varied positively with annual adult survival rates. Furthermore, species from drier and colder environments exhibited lower MaxCort than mesic and tropical species; T was lowest in species from tropical environments. These findings suggest that Cort0, MaxCort and T modulate key vertebrate life-history responses to the environment, with Cort0 supporting energetically demanding processes, MaxCort promoting survival and T being related to mating success.

  5. Global life satisfaction predicts ambulatory affect, stress, and cortisol in daily life in working adults.

    PubMed

    Smyth, Joshua M; Zawadzki, Matthew J; Juth, Vanessa; Sciamanna, Christopher N

    2017-04-01

    Global life satisfaction has been linked with long-term health advantages, yet how life satisfaction impacts the trajectory of long-term health is unclear. This paper examines one such possible mechanism-that greater life satisfaction confers momentary benefits in daily life that accumulate over time. A community sample of working adults (n = 115) completed a measure of life satisfaction and then three subsequent days of ecological momentary assessment surveys (6 times/day) measuring affect (i.e., emotional valence, arousal), and perceived stress, and also provided salivary cortisol samples. Multilevel models indicated that people with higher (vs. lower) levels of life satisfaction reported better momentary affect, less stress, marginally lower momentary levels and significantly altered diurnal slopes of cortisol. Findings suggest individuals with high global life satisfaction have advantageous daily experiences, providing initial evidence for potential mechanisms through which global life satisfaction may help explain long-term health benefits.

  6. Life-history strategy determines constraints on immune function.

    PubMed

    Parker, Benjamin J; Barribeau, Seth M; Laughton, Alice M; Griffin, Lynn H; Gerardo, Nicole M

    2017-05-01

    Determining the factors governing investment in immunity is critical to understanding host-pathogen ecological and evolutionary dynamics. Studies often consider disease resistance in the context of life-history theory, with the expectation that investment in immunity will be optimized in anticipation of disease risk. Immunity, however, is constrained by context-dependent fitness costs. How the costs of immunity vary across life-history strategies has yet to be considered. Pea aphids are typically unwinged but produce winged offspring in response to high population densities and deteriorating conditions. This is an example of polyphenism, a strategy used by many organisms to adjust to environmental cues. The goal of this study was to examine the relationship between the fitness costs of immunity, pathogen resistance and the strength of an immune response across aphid morphs that differ in life-history strategy but are genetically identical. We measured fecundity of winged and unwinged aphids challenged with a heat-inactivated fungal pathogen, and found that immune costs are limited to winged aphids. We hypothesized that these costs reflect stronger investment in immunity in anticipation of higher disease risk, and that winged aphids would be more resistant due to a stronger immune response. However, producing wings is energetically expensive. This guided an alternative hypothesis - that investing resources into wings could lead to a reduced capacity to resist infection. We measured survival and pathogen load after live fungal infection, and we characterized the aphid immune response to fungi by measuring immune cell concentration and gene expression. We found that winged aphids are less resistant and mount a weaker immune response than unwinged aphids, demonstrating that winged aphids pay higher costs for a less effective immune response. Our results show that polyphenism is an understudied factor influencing the expression of immune costs. More generally, our work

  7. Immobile and mobile life-history stages have different thermal physiologies in a lizard.

    PubMed

    Telemeco, Rory S

    2014-01-01

    Temperature affects multiple aspects of an organism's biology and thus defines a major axis of the fundamental niche. For ectotherms, variation in the thermal environment is particularly important because most of these taxa have a limited capacity to thermoregulate via metabolic heat production. While temperature affects all life-history stages, stages can differ in their ability to respond to the thermal environment. For example, in oviparous organisms, free-living adults can behaviorally thermoregulate, whereas developing embryos are at the mercy of the nest environment. These differences in the realized thermal environment should select for life-history stages to have different thermal tolerances, although this has been rarely examined. I tested the hypothesis that stage-specific thermal reaction norms can evolve independently by using southern alligator lizards (Elgaria multicarinata, Anguidae). Using incubation experiments (five temperatures: 24°, 26°, 28°, 30°, and 32°C), I described the thermal reaction norm for embryonic development and compared these results to previous studies on the thermal ecology of adults. Offspring survivorship and morphology were similarly affected by incubation temperature. While developing embryos had the same optimum temperature as adults (approximately 28°C), the breadth of their thermal reaction norms differed. My results suggest that developing embryos of E. multicarinata are more sensitive to variation in the average thermal environment than are adults. Variation in the thermal sensitivity of life-history stages might be common and has implications for how organisms respond to variation in the thermal environment. Identifying those life-history stages that are most sensitive/limiting will be important for developing models that best predict species' responses to impending environmental change.

  8. Movements of blue sharks (Prionace glauca) across their life history.

    PubMed

    Vandeperre, Frederic; Aires-da-Silva, Alexandre; Fontes, Jorge; Santos, Marco; Serrão Santos, Ricardo; Afonso, Pedro

    2014-01-01

    Spatial structuring and segregation by sex and size is considered to be an intrinsic attribute of shark populations. These spatial patterns remain poorly understood, particularly for oceanic species such as blue shark (Prionace glauca), despite its importance for the management and conservation of this highly migratory species. This study presents the results of a long-term electronic tagging experiment to investigate the migratory patterns of blue shark, to elucidate how these patterns change across its life history and to assess the existence of a nursery area in the central North Atlantic. Blue sharks belonging to different life stages (n = 34) were tracked for periods up to 952 days during which they moved extensively (up to an estimated 28.139 km), occupying large parts of the oceanic basin. Notwithstanding a large individual variability, there were pronounced differences in movements and space use across the species' life history. The study provides strong evidence for the existence of a discrete central North Atlantic nursery, where juveniles can reside for up to at least 2 years. In contrast with previously described nurseries of coastal and semi-pelagic sharks, this oceanic nursery is comparatively vast and open suggesting that shelter from predators is not its main function. Subsequently, male and female blue sharks spatially segregate. Females engage in seasonal latitudinal migrations until approaching maturity, when they undergo an ontogenic habitat shift towards tropical latitudes. In contrast, juvenile males generally expanded their range southward and apparently displayed a higher degree of behavioural polymorphism. These results provide important insights into the spatial ecology of pelagic sharks, with implications for the sustainable management of this heavily exploited shark, especially in the central North Atlantic where the presence of a nursery and the seasonal overlap and alternation of different life stages coincides with a high fishing

  9. Movements of Blue Sharks (Prionace glauca) across Their Life History

    PubMed Central

    Vandeperre, Frederic; Aires-da-Silva, Alexandre; Fontes, Jorge; Santos, Marco; Serrão Santos, Ricardo; Afonso, Pedro

    2014-01-01

    Spatial structuring and segregation by sex and size is considered to be an intrinsic attribute of shark populations. These spatial patterns remain poorly understood, particularly for oceanic species such as blue shark (Prionace glauca), despite its importance for the management and conservation of this highly migratory species. This study presents the results of a long-term electronic tagging experiment to investigate the migratory patterns of blue shark, to elucidate how these patterns change across its life history and to assess the existence of a nursery area in the central North Atlantic. Blue sharks belonging to different life stages (n = 34) were tracked for periods up to 952 days during which they moved extensively (up to an estimated 28.139 km), occupying large parts of the oceanic basin. Notwithstanding a large individual variability, there were pronounced differences in movements and space use across the species' life history. The study provides strong evidence for the existence of a discrete central North Atlantic nursery, where juveniles can reside for up to at least 2 years. In contrast with previously described nurseries of coastal and semi-pelagic sharks, this oceanic nursery is comparatively vast and open suggesting that shelter from predators is not its main function. Subsequently, male and female blue sharks spatially segregate. Females engage in seasonal latitudinal migrations until approaching maturity, when they undergo an ontogenic habitat shift towards tropical latitudes. In contrast, juvenile males generally expanded their range southward and apparently displayed a higher degree of behavioural polymorphism. These results provide important insights into the spatial ecology of pelagic sharks, with implications for the sustainable management of this heavily exploited shark, especially in the central North Atlantic where the presence of a nursery and the seasonal overlap and alternation of different life stages coincides with a high fishing

  10. An age-size reaction norm yields insight into environmental interactions affecting life-history traits: a factorial study of larval development in the malaria mosquito Anopheles gambiae sensu stricto.

    PubMed

    Phelan, Conan; Rotiberg, Bernard D

    2013-07-01

    Environmental factors frequently act nonindependently to determine growth and development of insects. Because age and size at maturity strongly influence population dynamics, interaction effects among environmental variables complicate the task of predicting dynamics of insect populations under novel conditions. We reared larvae of the African malaria mosquito Anopheles gambiae sensu stricto (s.s.) under three factors relevant to changes in climate and land use: food level, water depth, and temperature. Each factor was held at two levels in a fully crossed design, for eight experimental treatments. Larval survival, larval development time, and adult size (wing length) were measured to indicate the importance of interaction effects upon population-level processes. For age and size at emergence, but not survival, significant interaction effects were detected for all three factors, in addition to sex. Some of these interaction effects can be understood as consequences of how the different factors influence energy usage in the context of a nonindependent relationship between age and size. Experimentally assessing interaction effects for all potential future sets of conditions is intractable. However, considering how different factors affect energy usage within the context of an insect's evolved developmental program can provide insight into the causes of complex environmental effects on populations.

  11. Hot tadpoles from cold environments need more nutrients--life history and stoichiometry reflects latitudinal adaptation.

    PubMed

    Liess, Antonia; Rowe, Owen; Guo, Junwen; Thomsson, Gustaf; Lind, Martin I

    2013-11-01

    1. High-latitude species (and populations within species) are adapted to short and cold summers. They often have high growth and development rates to fully use the short growing season and mature before the onset of winter. 2. Within the context of ecological stoichiometry theory, this study combines ecology with evolution by relating latitudinal life-history adaptations to their molecular consequences in body nutrient composition in Rana temporaria tadpoles. 3. Temperature and food quality were manipulated during the development of tadpoles from Arctic and Boreal origins. We determined tadpole growth rate, development rate, body size and nutrient content, to test whether (i) Arctic tadpoles could realize higher growth rates and development rates with the help of higher-quality food even when food quantity was unchanged, (ii) Arctic and Boreal tadpoles differed in their stoichiometric (and life history) response to temperature changes, (iii) higher growth rates lead to higher tadpole P content (growth rate hypothesis) and (iv) allometric scaling affects tadpole nutrient allocation. 4. We found that especially Arctic tadpoles grew and developed faster with the help of higher-quality food and that tadpoles differed in their stoichiometric (and life history) response to temperature changes depending on region of origin (probably due to different temperature optima). There was no evidence that higher growth rates mediated the positive effect of temperature on tadpole P content. On the contrary, the covariate growth rate was negatively connected with tadpole P content (refuting the growth rate hypothesis). Lastly, tadpole P content was not related to body size, but tadpole C content was higher in larger tadpoles, probably due to increased fat storage. 5. We conclude that temperature had a strong effect on tadpole life history, nutrient demand and stoichiometry and that this effect depended on the evolved life history.

  12. Materialism, affective states, and life satisfaction: case of Croatia.

    PubMed

    Lipovčan, Ljiljana Kaliterna; Prizmić-Larsen, Zvjezdana; Brkljačić, Tihana

    2015-01-01

    In recent years, a number of studies have used Material Values Scale (MVS) to assess beliefs about importance to own material things. The aims of this study were to validate the MVS scale and to explore the relationships between materialistic values and well-being of Croatian citizens. The study was carried out on a representative sample of N = 1129 Croatian citizens. We used the short 9-item version of the MVS, life satisfaction rating, ratings of two positive (Positive affect) and four negative emotions (Negative affect) over the past month, and demographic variables (age, gender, income). The original dimensionality of the MVS was not confirmed; confirmatory factor analyses yielded two instead of three factors, Happiness and Centrality/Success. When controlled for income, gender and age, the Happiness dimension predicted Life satisfaction and both Positive and Negative affect, indicating that people who believed that the material goods in ones life leads to happiness reported to have lower life satisfaction, lower level of positive affect and higher level of negative affect over the past month. The Centrality/Success dimension was positively related to Positive affect, indicating that the belief that possessions play a central role in enjoyment leads to more frequent experiences of happiness and satisfaction over the past month.

  13. Sexual systems and life history of barnacles: a theoretical perspective.

    PubMed

    Yamaguchi, Sachi; Charnov, Eric L; Sawada, Kota; Yusa, Yoichi

    2012-09-01

    Thoracican barnacles show one of the most diverse sexual systems in animals: hermaphroditism, dioecy (males and females), and androdioecy (males and hermaphrodites). In addition, when present, male barnacles are very small and are called "dwarf males". The diverse sexual systems and male dwarfism in this taxon have attracted both theoretical and empirical biologists. In this article, we review the theoretical studies on barnacles' sexual systems in the context of sex allocation and life history theories. We first introduce the sex allocation models by Charnov, especially in relation to the mating group size, and a new expansion of his models is also proposed. We then explain three studies by Yamaguchi et al., who have studied the interaction between sex allocation and life history in barnacles. These studies consistently showed that limited mating opportunity favors androdioecy and dioecy over hermaphroditism. In addition, other factors, such as rates of survival and availability of food, are also important. We discuss the importance of empirical studies testing these predictions and how empirical studies interact with theoretical constructs.

  14. Life history, immunity, Peto's paradox and tumours in birds.

    PubMed

    Møller, A P; Erritzøe, J; Soler, J J

    2017-03-02

    Cancer and tumours may evolve in response to life-history trade-offs between growth and duration of development on one hand, and between growth and maintenance of immune function on the other. Here, we tested whether (i) bird species with slow developmental rates for their body size experience low incidence of tumours because slow development allows for detection of rapid proliferation of cell lineages. We also test whether (ii) species with stronger immune response during development are more efficient at detecting tumour cells and hence suffer lower incidence of tumours. Finally, we tested Peto's paradox, that there is a positive relationship between tumour incidence and body mass. We used information on developmental rates and body mass from the literature and of tumour incidence (8468 birds) and size of the bursa of Fabricius for 7659 birds brought to a taxidermist in Denmark. We found evidence of the expected negative relationship between incidence of tumours and developmental rates and immunity after controlling for the positive association between tumour incidence and body size. These results suggest that evolution has modified the incidence of tumours in response to life history and that Peto's paradox may be explained by covariation between body mass, developmental rates and immunity.

  15. Life history and locomotion in Cebus capucinus and Alouatta palliata.

    PubMed

    Bezanson, Michelle

    2009-11-01

    As an individual matures from birth to adulthood, many factors may influence the positional repertoire. The biological and behavioral changes that accompany a growing individual are expected to influence foraging strategy, social status and interaction, diet, predator avoidance strategies, and ultimately positional behavior as a behavioral link between anatomy and the environment. In this work, positional behavior is considered as an important feature of life history in juvenile and adult white-faced capuchins (Cebus capucinus) and mantled howling monkeys (Alouatta palliata) inhabiting the same tropical forest in Costa Rica. During growth and development ontogenetic changes in body size, limb proportions, and motor skills are likely to influence locomotion and posture through the arboreal canopy. I collected data on positional behavior, activity, branch size, branch angle, and crown location during a 12-month period at Estación Biológica La Suerte in northeastern Costa Rica. Life history timing and differences in rates of growth did not predictably influence the development of adultlike positional behaviors in Cebus and Alouatta. Young Cebus resembled the adult pattern of positional behavior by 6 months of age while howlers exhibited significant differences in several positional behavior categories through 24 months of age. The positional repertoire of both species revealed similarities in the types of modes used during feed/forage and travel in juveniles and adults. Data presented here suggest that the environment exerts different pressures on growing Cebus and Alouatta that may relate to diet, energy expenditure, foraging skill, and/or social learning.

  16. Effects of Aquatic Insect Life History Patterns on Bioassessments

    NASA Astrophysics Data System (ADS)

    Fend, S. V.; Carter, J. L.; Weissich, P.

    2005-05-01

    Aquatic insect populations vary greatly over an annual cycle. Nevertheless, given practical constraints, biomonitoring programs focusing on these animals typically have broad sampling seasons (index periods). Stated or implicit assumptions are 1) replacement by different populations with similar environmental tolerance occurs, and/or 2) metrics can be generated that are sufficiently robust or can be seasonally adjusted. To support tests of seasonal variability in macroinvertebrate metrics, we analyzed life history patterns of dominant EPT species in 3 regulated and 3 non-regulated streams. Population peaks (recruitment periods) of taxa numerically dominant in both stream types (Baetis tricaudatus, Hydropsyche spp., and Malenka cf. californica) were asynchronous, even within streamflow category. Populations of some intolerant taxonomic groups occurring in non-regulated streams (e.g., Ephemerellidae) were restricted to the fall-spring period. Other groups (e.g., Rhyacophilidae, Heptageniidae) included species that maintained high summer populations. Therefore, defining an index period for all streams in a given area is difficult because life history patterns are often site-specific. Seasonal adjustments based on statistical properties of derived metrics may be useful for describing conditions over a large area but at the site level, behavior of individual populations may need to be considered for an accurate assessment.

  17. Life-history evolution and mitogenomic phylogeny of caecilian amphibians.

    PubMed

    San Mauro, Diego; Gower, David J; Müller, Hendrik; Loader, Simon P; Zardoya, Rafael; Nussbaum, Ronald A; Wilkinson, Mark

    2014-04-01

    We analyze mitochondrial genomes to reconstruct a robust phylogenetic framework for caecilian amphibians and use this to investigate life-history evolution within the group. Our study comprises 45 caecilian mitochondrial genomes (19 of them newly reported), representing all families and 27 of 32 currently recognized genera, including some for which molecular data had never been reported. Support for all relationships in the inferred phylogenetic tree is high to maximal, and topology tests reject all investigated alternatives, indicating an exceptionally robust molecular phylogenetic framework of caecilian evolution consistent with current morphology-based supraspecific classification. We used the mitogenomic phylogenetic framework to infer ancestral character states and to assess correlation among three life-history traits (free-living larvae, viviparity, specialized pre-adult or vernal teeth), each of which occurs only in some caecilian species. Our results provide evidence that an ancestor of the Seychelles caecilians abandoned direct development and re-evolved a free-living larval stage. This study yields insights into the concurrent evolution of direct development and of vernal teeth in an ancestor of Teresomata that likely gave rise to skin-feeding (maternal dermatophagy) behavior and subsequently enabled evolution of viviparity, with skin feeding possibly a homologous precursor of oviduct feeding in viviparous caecilians.

  18. Seasonal variation in life history traits in two Drosophila species.

    PubMed

    Behrman, E L; Watson, S S; O'Brien, K R; Heschel, M S; Schmidt, P S

    2015-09-01

    Seasonal environmental heterogeneity is cyclic, persistent and geographically widespread. In species that reproduce multiple times annually, environmental changes across seasonal time may create different selection regimes that may shape the population ecology and life history adaptation in these species. Here, we investigate how two closely related species of Drosophila in a temperate orchard respond to environmental changes across seasonal time. Natural populations of Drosophila melanogaster and Drosophila simulans were sampled at four timepoints from June through November to assess seasonal change in fundamental aspects of population dynamics as well as life history traits. D. melanogaster exhibit pronounced change across seasonal time: early in the season, the population is inferred to be uniformly young and potentially represents the early generation following overwintering survivorship. D. melanogaster isofemale lines derived from the early population and reared in a common garden are characterized by high tolerance to a variety of stressors as well as a fast rate of development in the laboratory environment that declines across seasonal time. In contrast, wild D. simulans populations were inferred to be consistently heterogeneous in age distribution across seasonal collections; only starvation tolerance changed predictably over seasonal time in a parallel manner as in D. melanogaster. These results suggest fundamental differences in population and evolutionary dynamics between these two taxa associated with seasonal heterogeneity in environmental parameters and associated selection pressures.

  19. Cognitive ability influences reproductive life history variation in the wild.

    PubMed

    Cole, Ella F; Morand-Ferron, Julie; Hinks, Amy E; Quinn, John L

    2012-10-09

    Cognition has been studied intensively for several decades, but the evolutionary processes that shape individual variation in cognitive traits remain elusive [1-3]. For instance, the strength of selection on a cognitive trait has never been estimated in a natural population, and the possibility that positive links with life history variation [1-5] are mitigated by costs [6] or confounded by ecological factors remains unexplored in the wild. We assessed novel problem-solving performance in 468 wild great tits Parus major temporarily taken into captivity and subsequently followed up their reproductive performance in the wild. Problem-solver females produced larger clutches than nonsolvers. This benefit did not arise because solvers timed their breeding better, occupied better habitats, or compromised offspring quality or their own survival. Instead, foraging range size and day length were relatively small and short, respectively, for solvers, suggesting that they were more efficient at exploiting their environment. In contrast to the positive effect on clutch size, problem solvers deserted their nests more often, leading to little or no overall selection on problem-solving performance. Our results are consistent with the idea that variation in cognitive ability is shaped by contrasting effects on different life history traits directly linked to fitness [1, 3].

  20. Life histories of symbiotic rhizobia and mycorrhizal fungi.

    PubMed

    Denison, R Ford; Kiers, E Toby

    2011-09-27

    Research on life history strategies of microbial symbionts is key to understanding the evolution of cooperation with hosts, but also their survival between hosts. Rhizobia are soil bacteria known for fixing nitrogen inside legume root nodules. Arbuscular mycorrhizal (AM) fungi are ubiquitous root symbionts that provide plants with nutrients and other benefits. Both kinds of symbionts employ strategies to reproduce during symbiosis using host resources; to repopulate the soil; to survive in the soil between hosts; and to find and infect new hosts. Here we focus on the fitness of the microbial symbionts and how interactions at each of these stages has shaped microbial life-history strategies. During symbiosis, microbial fitness could be increased by diverting more resources to individual reproduction, but that may trigger fitness-reducing host sanctions. To survive in the soil, symbionts employ sophisticated strategies, such as persister formation for rhizobia and reversal of spore germination by mycorrhizae. Interactions among symbionts, from rhizobial quorum sensing to fusion of genetically distinct fungal hyphae, increase adaptive plasticity. The evolutionary implications of these interactions and of microbial strategies to repopulate and survive in the soil are largely unexplored.

  1. Genetic and life-history consequences of extreme climate events.

    PubMed

    Vincenzi, Simone; Mangel, Marc; Jesensek, Dusan; Garza, John Carlos; Crivelli, Alain J

    2017-02-08

    Climate change is predicted to increase the frequency and intensity of extreme climate events. Tests on empirical data of theory-based predictions on the consequences of extreme climate events are thus necessary to understand the adaptive potential of species and the overarching risks associated with all aspects of climate change. We tested predictions on the genetic and life-history consequences of extreme climate events in two populations of marble trout Salmo marmoratus that have experienced severe demographic bottlenecks due to flash floods. We combined long-term field and genotyping data with pedigree reconstruction in a theory-based framework. Our results show that after flash floods, reproduction occurred at a younger age in one population. In both populations, we found the highest reproductive variance in the first cohort born after the floods due to a combination of fewer parents and higher early survival of offspring. A small number of parents allowed for demographic recovery after the floods, but the genetic bottleneck further reduced genetic diversity in both populations. Our results also elucidate some of the mechanisms responsible for a greater prevalence of faster life histories after the extreme event.

  2. Seasonal variation in life history traits in two Drosophila species

    PubMed Central

    BEHRMAN, E. L.; WATSON, S. S.; O'BRIEN, K. R.; HESCHEL, M. S.; SCHMIDT, P. S.

    2016-01-01

    Seasonal environmental heterogeneity is cyclic, persistent and geographically widespread. In species that reproduce multiple times annually, environmental changes across seasonal time may create different selection regimes that may shape the population ecology and life history adaptation in these species. Here, we investigate how two closely related species of Drosophila in a temperate orchard respond to environmental changes across seasonal time. Natural populations of Drosophila melanogaster and Drosophila simulans were sampled at four timepoints from June through November to assess seasonal change in fundamental aspects of population dynamics as well as life history traits. D. melanogaster exhibit pronounced change across seasonal time: early in the season, the population is inferred to be uniformly young and potentially represents the early generation following overwintering survivorship. D. melanogaster isofemale lines derived from the early population and reared in a common garden are characterized by high tolerance to a variety of stressors as well as a fast rate of development in the laboratory environment that declines across seasonal time. In contrast, wild D. simulans populations were inferred to be consistently heterogeneous in age distribution across seasonal collections; only starvation tolerance changed predictably over seasonal time in a parallel manner as in D. melanogaster. These results suggest fundamental differences in population and evolutionary dynamics between these two taxa associated with seasonal heterogeneity in environmental parameters and associated selection pressures. PMID:26174167

  3. Ecology, Life History, and Management of Tropilaelaps Mites.

    PubMed

    de Guzman, Lilia I; Williams, Geoffrey R; Khongphinitbunjong, Kitiphong; Chantawannakul, Panuwan

    2017-03-15

    Parasitic mites are the major threat to the Western honey bee, Apis mellifera L. For much of the world, Varroa destructor Anderson & Trueman single-handedly inflicts unsurmountable problems to A. mellifera beekeeping. However, A. mellifera in Asia is also faced with another genus of destructive parasitic mite, Tropilaelaps. The life history of these two parasitic mites is very similar, and both have the same food requirements (i.e., hemolymph of developing brood). Hence, parasitism by Tropilaelaps spp., especially Tropilaelaps mercedesae and Tropilaelaps clareae, also results in death of immature brood or wing deformities in infested adult bees. The possible introduction of Tropilaelaps mites outside their current range heightens existing dilemmas brought by Varroa mites. In this review, we provide historic, as well as current information on the taxonomic status, life history, distribution and host range, diagnosis, and control of Tropilaelaps mites. Because the biology of Tropilaelaps mites is not well known, we also suggest areas of research that demand immediate attention. Any biological information about Tropilaelaps mites will provide useful information for the development of control measures against them.

  4. Metabolite changes during the life history of Porphyra haitanensis.

    PubMed

    Wang, X; Zhao, P; Luo, Q; Yan, X; Xu, J; Chen, J; Chen, H

    2015-05-01

    Plant metabolomics is essentially the comprehensive analysis of complex metabolites of plant extracts. Metabolic fingerprinting is an important part of plant metabolomics research. In this study, metabolic fingerprinting of different stages of the life history of the red alga Porphyra haitanensis was performed. The stages included conchocelis filaments, sporangial branchlets, conchosporangia, discharged conchospores and conchosporangial branchlets after conchospore discharge. Metabolite extracts were analysed with ultra-performance liquid chromatography coupled with electrospray ionisation quadrupole-time of flight mass spectrometry. Analyses profiles were subjected to principal components analysis and orthogonal projection to latent structures discriminant analysis using the SIMCA-P software for biomarker selection and identification. Based on the MS/MS spectra and data from the literature, potential biomarkers, mainly of phosphatidylcholine and lysophosphatidylcholine, were identified. Identification of these biomarkers suggested that plasma membrane phospholipids underwent major changes during the life history of P. haitanensis. The levels of phosphatidylcholine and lysophosphatidylcholine increased in sporangial branchlets and decreased in discharged conchospores. Moreover, levels of sphingaine (d18:0) decreased in sporangial branchlets and increased in discharged conchospores, which indicates that membrane lipids were increasingly synthesised as energy storage in sporangial branchlets, while energy was consumed in sporangial branchlets to discharged conchospores. A metabolomic study of different growth phases of P. haitanensis will enhance our understanding of its physiology and ecology.

  5. Life-history traits of the stone loach Barbatula barbatula.

    PubMed

    Vinyoles, D; de Sostoa, A; Franch, C; Maceda-Veiga, A; Casals, F; Caiola, N

    2010-07-01

    The life-history tactics of the stone loach Barbatula barbatula were studied in a Mediterranean-type climate stream (Matarranya River) located in the Ebro River basin (north-east Spain). Maximum observed ages were 2+ years in both sexes (1% of individuals), although only 0+ and 1+ year age groups were well represented. It is the lowest longevity reported for this species in its entire distribution. The seasonal growth period started in June and continued until November, but the pattern observed was different to northern populations. Barbatula barbatula in the Matarranya River was a multiple spawner, releasing small batches of oocytes between April and June. The fecundity of females was higher and the size of oocytes smaller in 1984 than in 1985. The relative fecundity (number of ripening and ripe oocytes g(-1) of fish) was lower than in northern European populations. The role of the particular environmental conditions of a Mediterranean stream was discussed in relation to the life-history tactics of B. barbatula.

  6. Population-specific life histories contribute to metapopulation viability

    USGS Publications Warehouse

    Halsey, Samniqueka J.; Bell, Timothy J.; McEachern, Kathryn; Pavlovic, Noel B.

    2016-01-01

    Restoration efforts can be improved by understanding how variations in life-history traits occur within populations of the same species living in different environments. This can be done by first understanding the demographic responses of natural occurring populations. Population viability analysis continues to be useful to species management and conservation with sensitivity analysis aiding in the understanding of population dynamics. In this study, using life-table response experiments and elasticity analyses, we investigated how population-specific life-history demographic responses contributed to the metapopulation viability of the Federally threatened Pitcher's thistle (Cirsium pitcheri). Specifically, we tested the following hypotheses: (1) Subpopulations occupying different environments within a metapopulation have independent demographic responses and (2) advancing succession results in a shift from a demographic response focused on growth and fecundity to one dominated by stasis. Our results showed that reintroductions had a positive contribution to the metapopulation growth rate as compared to native populations which had a negative contribution. We found no difference in succession on the contribution to metapopulation viability. In addition, we identified distinct population-specific contributions to metapopulation viability and were able to associate specific life-history demographic responses. For example, the positive impact of Miller High Dunes population on the metapopulation growth rate resulted from high growth contributions, whereas increased time of plant in stasis for the State Park Big Blowout population resulted in negative contributions. A greater understanding of how separate populations respond in their corresponding environment may ultimately lead to more effective management strategies aimed at reducing extinction risk. We propose the continued use of sensitivity analyses to evaluate population-specific demographic influences on

  7. Salamander paedomorphosis: linking thyroid hormone to life history and life cycle evolution.

    PubMed

    Johnson, Carlena K; Voss, S Randal

    2013-01-01

    Many salamanders have biphasic life cycles with aquatic larval and terrestrial adult phases. In these species, the transition between phases-metamorphosis-requires thyroid hormone (TH) activation of transcriptional programs that cause regression of larval traits and development of adult traits. During salamander evolution, TH signaling pathways have been altered in biphasic species to yield paedomorphic salamanders that retain larval traits and attain sexual maturity in larval aquatic habitats. We review literature concerning the ecology, evolution, and hormonal regulation of metamorphic, paedomorphic, and facultative salamander life histories. We then discuss recent microarray results that detail gene expression signatures of metamorphosis and paedomorphosis, and genetic results that establish TH responsiveness as a continuous trait with a quantitative trait locus (QTL) basis. TH-responsive QTL from ambystomatid salamanders explain variation in metamorphic timing, expression of metamorphosis versus paedomorphosis, and adult fitness traits. We propose a model for salamander life history evolution that links adaptation to aquatic habitats with TH-responsive loci that pleiotropically alter metamorphic timing and adult body size. Future studies that adopt genetic and genomic approaches will further establish salamanders as ideal models for investigating TH signaling mechanisms that regulate postembryonic development and the expression of alternate life histories.

  8. Lifetime growth in wild meerkats: incorporating life history and environmental factors into a standard growth model.

    PubMed

    English, Sinéad; Bateman, Andrew W; Clutton-Brock, Tim H

    2012-05-01

    Lifetime records of changes in individual size or mass in wild animals are scarce and, as such, few studies have attempted to model variation in these traits across the lifespan or to assess the factors that affect them. However, quantifying lifetime growth is essential for understanding trade-offs between growth and other life history parameters, such as reproductive performance or survival. Here, we used model selection based on information theory to measure changes in body mass over the lifespan of wild meerkats, and compared the relative fits of several standard growth models (monomolecular, von Bertalanffy, Gompertz, logistic and Richards). We found that meerkats exhibit monomolecular growth, with the best model incorporating separate growth rates before and after nutritional independence, as well as effects of season and total rainfall in the previous nine months. Our study demonstrates how simple growth curves may be improved by considering life history and environmental factors, which may be particularly relevant when quantifying growth patterns in wild populations.

  9. Correlated evolution of sexual system and life-history traits in mosses.

    PubMed

    Crawford, Monique; Jesson, Linley K; Garnock-Jones, Phil J

    2009-05-01

    In mosses, separate and combined sexes are evolutionarily labile, yet factors selecting for this variation are unknown. In this study, we investigate phylogenetic correlations between sexual system and five life-history traits (asexual reproduction, chromosome number, gametophore length, spore size, and seta length). We assigned states to species on a large-scale phylogeny of mosses and used maximum likelihood analyses to test for the correlations and investigate the sequence of trait acquisition. Mosses in lineages with separate sexes were significantly more likely to be large, whereas those in lineages with combined sexes had higher chromosome numbers. Moreover, evolutionary transitions to separate sexes were more likely to occur in lineages with small spores. There was no support for a correlation between asexual reproduction and separate sexes. These results suggest that sexual system evolution is influenced by traits affecting mate availability and the dispersal of gametes and spores, and provides evidence for the existence of syndromes of life-history traits in mosses.

  10. The changing role of mammal life histories in Late Quaternary extinction vulnerability on continents and islands.

    PubMed

    Lyons, S Kathleen; Miller, Joshua H; Fraser, Danielle; Smith, Felisa A; Boyer, Alison; Lindsey, Emily; Mychajliw, Alexis M

    2016-06-01

    Understanding extinction drivers in a human-dominated world is necessary to preserve biodiversity. We provide an overview of Quaternary extinctions and compare mammalian extinction events on continents and islands after human arrival in system-specific prehistoric and historic contexts. We highlight the role of body size and life-history traits in these extinctions. We find a significant size-bias except for extinctions on small islands in historic times. Using phylogenetic regression and classification trees, we find that while life-history traits are poor predictors of historic extinctions, those associated with difficulty in responding quickly to perturbations, such as small litter size, are good predictors of prehistoric extinctions. Our results are consistent with the idea that prehistoric and historic extinctions form a single continuing event with the same likely primary driver, humans, but the diversity of impacts and affected faunas is much greater in historic extinctions.

  11. Behavioural consistency and life history of Rana dalmatina tadpoles.

    PubMed

    Urszán, Tamás János; Török, János; Hettyey, Attila; Garamszegi, László Zsolt; Herczeg, Gábor

    2015-05-01

    The focus of evolutionary behavioural ecologists has recently turned towards understanding the causes and consequences of behavioural consistency, manifesting either as animal personality (consistency in a single behaviour) or behavioural syndrome (consistency across more behaviours). Behavioural type (mean individual behaviour) has been linked to life-history strategies, leading to the emergence of the integrated pace-of-life syndrome (POLS) theory. Using Rana dalmatina tadpoles as models, we tested if behavioural consistency and POLS could be detected during the early ontogenesis of this amphibian. We targeted two ontogenetic stages and measured activity, exploration and risk-taking in a common garden experiment, assessing both individual behavioural type and intra-individual behavioural variation. We observed that activity was consistent in all tadpoles, exploration only became consistent with advancing age and risk-taking only became consistent in tadpoles that had been tested, and thus disturbed, earlier. Only previously tested tadpoles showed trends indicative of behavioural syndromes. We found an activity-age at metamorphosis POLS in the previously untested tadpoles irrespective of age. Relative growth rate correlated positively with the intra-individual variation of activity of the previously untested older tadpoles. In previously tested older tadpoles, intra-individual variation of exploration correlated negatively and intra-individual variation of risk-taking correlated positively with relative growth rate. We provide evidence for behavioural consistency and POLS in predator- and conspecific-naive tadpoles. Intra-individual behavioural variation was also correlated to life history, suggesting its relevance for the POLS theory. The strong effect of moderate disturbance related to standard behavioural testing on later behaviour draws attention to the pitfalls embedded in repeated testing.

  12. Life history characteristics of diorhabda carinulata under various temperatures.

    PubMed

    Acharya, Kumud; Sueki, Sachiko; Conrad, Benjamin; Dudley, Tom L; Bean, Dan W; Osterberg, John C

    2013-06-01

    Tamarisk leaf beetles, Diorhabda spp., have been released in the western United States as a biological control agent for the invasive weed Tamarix spp. There have been a few studies on the life cycle, host preferences, and field observations of Diorhabda; however, their ecophysiological characteristics under various temperature regimes are not clearly understood. In this study, life history characteristics such as growth, fecundity, and mortality of Diorhabda Carinulata (Desbrochers), the species established in the Colorado River basin, were investigated under various temperatures. Beetles were housed at various temperatures (room, constant high, and variable high) and their life cycle from eggs to reproductive adult was observed. Body size at various larval and adult stages, as well as their developmental time decreased with increasing temperature. Between the two temperature treatments, beetles at diurnally fluctuating temperature (variable high treatment) grew slower and produced fewer eggs per clutch when compared with the constant high treatment. Despite smaller in size, beetles grew fastest at the constant high temperature and produced most eggs per clutch compared with the other two treatments. Overall, severely high temperatures seem to have a debilitating effect on Diorhabda at early larval stages with nearly 50% mortality. The study has potential implications for the tamarisk beetle biocontrol program in the southwestern United States.

  13. Life history dependent morphometric variation in stream-dwelling Atlantic salmon

    USGS Publications Warehouse

    Letcher, B.H.

    2003-01-01

    The time course of morphometric variation among life histories for stream-dwelling Atlantic salmon (Salmo salar L.) parr (age-0+ to age-2+) was analyzed. Possible life histories were combinations of parr maturity status in the autumn (mature or immature) and age at outmigration (smolt at age-2+ or later age). Actual life histories expressed with enough fish for analysis in the 1997 cohort were immature/age-2+ smolt, mature/age-2 +smolt, and mature/age-2+ non-smolt. Tagged fish were assigned to one of the three life histories and digital pictures from the field were analyzed using landmark-based geometric morphometrics. Results indicated that successful grouping of fish according to life history varied with fish age, but that fish could be grouped before the actual expression of the life histories. By March (age-1+), fish were successfully grouped using a descriptive discriminant function and successful assignment ranged from 84 to 97% for the remainder of stream residence. A jackknife of the discriminant function revealed an average life history prediction success of 67% from age-1+ summer to smolting. Low sample numbers for one of the life histories may have limited prediction success. A MANOVA on the shape descriptors (relative warps) also indicated significant differences in shape among life histories from age-1+ summer through to smolting. Across all samples, shape varied significantly with size. Within samples, shape did not vary significantly with size for samples from December (age-0+) to May (age-1+). During the age-1+ summer however, shape varied significantly with size, but the relationship between shape and size was not different among life histories. In the autumn (age-1+) and winter (age-2+), life history differences explained a significant portion of the change in shape with size. Life history dependent morphometric variation may be useful to indicate the timing of early expressions of life history variation and as a tool to explore temporal and

  14. How Do Volcanoes Affect Human Life? Integrated Unit.

    ERIC Educational Resources Information Center

    Dayton, Rebecca; Edwards, Carrie; Sisler, Michelle

    This packet contains a unit on teaching about volcanoes. The following question is addressed: How do volcanoes affect human life? The unit covers approximately three weeks of instruction and strives to present volcanoes in an holistic form. The five subject areas of art, language arts, mathematics, science, and social studies are integrated into…

  15. Preadult life history variation determines adult transcriptome expression

    PubMed Central

    Etges, William J.; de Oliveira, Cássia; Rajpurohit, Subhash; Gibbs, Allen G.

    2015-01-01

    Preadult determinants of adult fitness and behavior have been documented in a variety of organisms with complex life cycles, but little is known about expression patterns of genes underlying these adult traits. We explored the effects of differences in egg to adult development time on adult transcriptome and cuticular hydrocarbon variation in order to understand the nature of the genetic correlation between preadult development time and premating isolation between populations of Drosophila mojavensis reared in different host cactus environments. Transcriptome variation was analyzed separately in flies reared on each host and revealed that hundreds of genes in adults were differentially expressed (FDR P < 0.05) due to development time differences. For flies reared on pitaya agria cactus, longer preadult development times caused increased expression of genes in adults enriched for ribosome production, protein metabolism, chromatin remodeling, and regulation of alternate splicing and transcription. Baja California flies reared on organ pipe cactus showed fewer differentially expressed genes in adults due to longer preadult development time, but these were enriched for ATP synthesis and the TCA cycle. Mainland flies reared on organ pipe cactus with shorter development times showed increased transcription of genes enriched for mitochondria and energy production, protein synthesis, and glucose metabolism: adults with longer development times had increased expression of genes enriched for adult life span, cuticle proteins and ion binding, although most differentially expressed genes were unannotated. Differences due to population, sex, mating status, and their interactions were also assessed. Adult cuticular hydrocarbon profiles also showed shifts due to egg to adult development time, and were influenced by population and mating status. These results help to explain why preadult life history variation determines subsequent expression of the adult transcriptome along with

  16. Preadult life history variation determines adult transcriptome expression.

    PubMed

    Etges, William J; de Oliveira, Cássia; Rajpurohit, Subhash; Gibbs, Allen G

    2016-02-01

    Preadult determinants of adult fitness and behaviour have been documented in a variety of organisms with complex life cycles, but little is known about expression patterns of genes underlying these adult traits. We explored the effects of differences in egg-to-adult development time on adult transcriptome and cuticular hydrocarbon variation in order to understand the nature of the genetic correlation between preadult development time and premating isolation between populations of Drosophila mojavensis reared in different host cactus environments. Transcriptome variation was analysed separately in flies reared on each host and revealed that hundreds of genes in adults were differentially expressed (FDR P < 0.05) due to development time differences. For flies reared on pitaya agria cactus, longer preadult development times caused increased expression of genes in adults enriched for ribosome production, protein metabolism, chromatin remodelling and regulation of alternate splicing and transcription. Baja California flies reared on organ pipe cactus showed fewer differentially expressed genes in adults due to longer preadult development time, but these were enriched for ATP synthesis and the TCA cycle. Mainland flies reared on organ pipe cactus with shorter development times showed increased transcription of genes enriched for mitochondria and energy production, protein synthesis and glucose metabolism: adults with longer development times had increased expression of genes enriched for adult life span, cuticle proteins and ion binding, although most differentially expressed genes were unannotated. Differences due to population, sex, mating status and their interactions were also assessed. Adult cuticular hydrocarbon profiles also showed shifts due to egg-to-adult development time and were influenced by population and mating status. These results help to explain why preadult life history variation determines subsequent expression of the adult transcriptome along with

  17. Dynamics and life histories of northern ungulates in changing environments

    NASA Astrophysics Data System (ADS)

    Hendrichsen, D. K.

    2011-12-01

    Regional climate and local weather conditions can profoundly influence life history parameters (growth, survival, fecundity) and population dynamics in northern ungulates (Post and Stenseth 1999, Coulson et al. 2001). The influence is both direct, for example through reduced growth or survival (Aanes et al. 2000, Tyler et al. 2008), and indirect, for example through changes in resource distribution, phenology and quality, changes which subsequently influence consumer dynamics (Post et al. 2008). By comparing and contrasting data from three spatially independent populations of ungulates, I discuss how variation in local weather parameters and vegetation growth influence spatial and temporal dynamics through changes in life history parameters and/or behavioural dynamics. The data originate from long term (11-15 years) monitoring data from three populations of ungulates in one subarctic and two high Arctic sites; semi-domesticated reindeer (Rangifer tarandus tarandus) in northern Norway, Svalbard reindeer (R. t. platyrhynchus) on Spitsbergen and muskoxen (Ovibos moschatus) in Northeast Greenland. The results show that juvenile animals can be particularly vulnerable to changes in their environment, and that this is mirrored to different degrees in the spatio-temporal dynamics of the three populations. Adverse weather conditions, acting either directly or mediated through access to and quality of vegetation, experienced by young early in life, or even by their dams during pregnancy, can lead to reduced growth, lower survival and reduced reproductive performance later in life. The influence of current climatic variation, and the predictions of how local weather conditions may change over time, differs between the three sites, resulting in potentially different responses in the three populations. Aanes R, Saether BE and Øritsland NA. 2000. Fluctuations of an introduced population of Svalbard reindeer: the effects of density dependence and climatic variation. Ecography

  18. Disturbance, life history, and optimal management for biodiversity

    USGS Publications Warehouse

    Guo, Q.

    2003-01-01

    Both frequency and intensity of disturbances in many ecosystems have been greatly enhanced by increasing human activities. As a consequence, the short-lived plant species including many exotics might have been dramatically increased in term of both richness and abundance on our planet while many long-lived species might have been lost. Such conclusions can be drawn from broadly observed successional cycles in both theoretical and empirical studies. This article discusses two major issues that have been largely overlooked in current ecosystem management policies and conservation efforts, i.e., life history constraints and future global warming trends. It also addresses the importance of these two factors in balancing disturbance frequency and intensity for optimal biodiversity maintenance and ecosystem management.

  19. Encephalization quotients and life-history traits in the Sirenia

    USGS Publications Warehouse

    O'Shea, T.J.; Reep, R.L.

    1990-01-01

    Relative brain size in the Sirenia is unusually small. Encephalization quotients are 0.27 for Florida manatees (Trichechus manatus) and 0.38 for dugongs (Dugong dugon). Estimates for Steller's sea cow (Hydrodamalis gigas) range from 0.12 to 0.19. These values are among the lowest known for Recent mammals, and seemingly have changed little since the Eocene. A body plan specialized for the aquatic environment does not account for low encephalization quotients; values are substantially less than predicted based on cetacean or pinniped allometry. Life-history, ecological, and behavioral traits of the Sirenia are typical of relatively large-brained species. Low quality food and a low metabolic rate, however, are characteristic of the Sirenia and other small-brained mammals. Acting through prolonged postnatal growth, selection also likely favored large body size in the Sirenia without a correlated increase in brain size.

  20. Unusual larval habitats and life history of chironomid (Diptera) genera

    USGS Publications Warehouse

    Hudson, Patrick L.

    1987-01-01

    Ninety-three genera, representing all subfamilies of Chironomidae, are organized into 9 categories of unusual habitats or life history including hygropetric, riparian (bank, floodplain, upland), hyporheic, symbiotic, and intertidal; others live in water held in plants or mine into unusual substrates. In riparian zones precise location of optimum habitat is difficult to determine as is definition of habitat within the continuum from shoreline to upland areas. The ecological importance of the riparian group appears to lie in its processing of coarse particulate matter along the floodplain of streams and rivers. All riparian genera are zoogeographically useful and can be used in reconstructing evolutionary dispersal pathways because they are adapted to unique habits that have remained largely undisturbed by human activities.

  1. How Life History Can Sway the Fixation Probability of Mutants.

    PubMed

    Li, Xiang-Yi; Kurokawa, Shun; Giaimo, Stefano; Traulsen, Arne

    2016-07-01

    In this work, we study the effects of demographic structure on evolutionary dynamics when selection acts on reproduction, survival, or both. In contrast to the previously discovered pattern that the fixation probability of a neutral mutant decreases while the population becomes younger, we show that a mutant with a constant selective advantage may have a maximum or a minimum of the fixation probability in populations with an intermediate fraction of young individuals. This highlights the importance of life history and demographic structure in studying evolutionary dynamics. We also illustrate the fundamental differences between selection on reproduction and selection on survival when age structure is present. In addition, we evaluate the relative importance of size and structure of the population in determining the fixation probability of the mutant. Our work lays the foundation for also studying density- and frequency-dependent effects in populations when demographic structures cannot be neglected.

  2. Life history and ecology of Cambarus halli (Hobbs)

    USGS Publications Warehouse

    Dennard, S.; Peterson, J.T.; Hawthorne, E.S.

    2009-01-01

    The life history of Cambarus halli, a crayfish endemic to the Tallapoosa River Basin, GA, was studied at four sites within the Tallapoosa River. Two sites had allopatric populations of C. halli, and two sites had populations of C. halli sympatric with C. englishi. Three age classes existed across sites. For Cambarus halli, total number of pleopodal eggs was positively related to carapace length, but egg size was only weakly positively related to carapace length. Cambarus halli were smaller across age classes at sympatric sites, but had greater growth rates than at allopatric sites. Cambarus halli density estimates were lower at sympatric sites, while proportions of reproductively active age-1 and age-2 individuals were higher at allopatric sites (63% vs. 33%).

  3. Habits of the Heart: Life History and the Developmental Neuroendocrinology of Emotion

    PubMed Central

    Worthman, Carol M.

    2013-01-01

    The centrality of emotion in cognition and social intelligence, as well as its impact on health, has intensified investigation into the causes and consequences of individual variation in emotion regulation. Central processing of experience directly informs regulation of endocrine axes, essentially forming a neuro-endocrine continuum integrating information intake, processing, and physiological and behavioral response. Two major elements of life history—resource allocation and niche partitioning—are served by linking cognitive-affective with physiologic and behavioral processes. Scarce cognitive resources (attention, memory, time) are allocated under guidance from affective co-processing. Affective-cognitive processing, in turn, regulates physiologic activity through neuro-endocrine outflow and thereby orchestrates energetic resource allocation and trade-offs, both acutely and through time. Reciprocally, peripheral activity (e.g., immunologic, metabolic or energetic markers) influences affective-cognitive processing. By guiding attention, memory, and behavior, affective-cognitive processing also informs individual stances toward, patterns of activity in, and relationships with the world. As such, it mediates processes of niche partitioning that adaptively exploit social and material resources. Developmental behavioral neurobiology has identified multiple factors that influence the ontogeny of emotion regulation to form affective and behavioral styles. Evidence is reviewed documenting roles for genetic, epigenetic, and experiential factors in the development of emotion regulation, social cognition and behavior with important implications for understanding mechanisms that underlie life history construction and the sources of differential health. Overall, this dynamic arena for research promises to link the biological bases of life history theory with the psychobehavioral phenomena that figure so centrally in quotidian experience and adaptation, particularly for

  4. Reproductive life history traits of female orangutans (Pongo spp.).

    PubMed

    Shumaker, Robert W; Wich, Serge A; Perkins, Lori

    2008-01-01

    Data from wild populations demonstrate that orangutans have the slowest life history of all the great apes. In this chapter, we provide an overview of reproduction and life history traits of female orangutans in the wild and captivity. This comparison of wild and captive data illustrates the variability that exists for orangutans. Wild orangutan females first reproduce at a mean age of 15.4 years, with an age range of 13-18 years, and they have a mean interbirth interval of 9.3 years. Wild male orangutans are conservatively estimated to live at least 58 years, and 53 years for females [1], and to date, there is no evidence to suggest that wild orangutans experience reproductive senescence. We use captive data from 2,566 individuals to show that in captivity orangutan females regularly begin reproducing at the age of 7 and have interbirth intervals that can be shorter than 1 year. We provide additional data that describe the onset and normalization of menses in a young adolescent orangutan as well as the reproductive cycles of three adult females of different ages. Although captive females routinely cycle and reproduce throughout much of their lifespan, age at last reproduction in captivity is 41, which is well before maximum female lifespan. To date, longevity in the wild and in captivity appears equivalent [2]. The reasons for the presence of a postreproductive lifespan in captivity as opposed to its absence in wild populations may be related to management issues. The above results indicate a need for more detailed comparisons between wild and captive orangutans using similar methodologies.

  5. Life-history tradeoffs and reproductive cycles in Spotted Owls

    USGS Publications Warehouse

    Stoelting, Ricka E.; Gutierrez, R.J.; Kendall, William; Peery, M. Zachariah

    2015-01-01

    The study of tradeoffs among life-history traits has long been key to understanding the evolution of life-history strategies. However, more recently, evolutionary ecologists have realized that reproductive costs have the potential to influence population dynamics. Here, we tested for costs of reproduction in the California Spotted Owl (Strix occidentalis occidentalis), and assessed whether costs of reproduction in year t − 1 on reproduction in year t could be responsible for regionally synchronized biennial cycles in reproductive output. Logistic regression analysis and multistate mark–recapture models with state uncertainty revealed that breeding reduced the likelihood of reproducing in the subsequent year by 16% to 38%, but had no influence on subsequent survival. We also found that costs of reproduction in year t − 1 were correlated with climatic conditions in year t, with evidence of higher costs during the dry phase of the El Niño–Southern Oscillation. Using a simulation-based population model, we showed that strong reproductive costs had the potential to create biennial cycles in population-level reproductive output; however, estimated costs of reproduction appeared to be too small to explain patterns observed in Spotted Owls. In the absence of strong reproductive costs, we hypothesize that observed natural cycles in the reproductive output of Spotted Owls are related to as-yet-unmeasured, regionally concordant fluctuations in environmental conditions or prey resources. Despite theoretical evidence for demographic effects, our analyses illustrate that linking tradeoffs to actual changes in population processes will be challenging because of the potential confounding effects of individual and environmental variation.

  6. Lifetime learning as a factor in life history education.

    PubMed

    Bullinaria, John A

    2009-01-01

    An artificial life approach is taken to explore the effect that lifetime learning can have on the evolution of certain life history traits, in particular the periods of protection that parents offer young, and the age at first reproduction of those young. The study begins by simulating the evolution of simple artificial neural network systems that must learn quickly to perform well on simple classification tasks, and determining if and when extended periods of parental protection emerge. It is concluded that longer periods of parental protection of children do offer clear learning advantages and better adult performance, but only if procreation is not allowed during the protection period. In this case, a compromise protection period evolves that balances the improved learning performance against reduced procreation period. The crucial properties of the neural learning processes are then abstracted out to explore the possibility of studying the effect of learning more generally and with better computational efficiency. Throughout, the implications of these stimulations for more realistic scenarios are discussed.

  7. Queen control of a key life-history event in a eusocial insect

    PubMed Central

    Holland, Jacob G.; Guidat, Florian S.; Bourke, Andrew F. G.

    2013-01-01

    In eusocial insects, inclusive fitness theory predicts potential queen–worker conflict over the timing of events in colony life history. Whether queens or workers control the timing of these events is poorly understood. In the bumble-bee Bombus terrestris, queens exhibit a ‘switch point’ in which they switch from laying diploid eggs yielding females (workers and new queens) to laying haploid eggs yielding males. By rearing foundress queens whose worker offspring were removed as pupae and sexing their eggs using microsatellite genotyping, we found that queens kept in the complete absence of adult workers still exhibit a switch point. Moreover, the timing of their switch points relative to the start of egg-laying did not differ significantly from that of queens allowed to produce normal colonies. The finding that bumble-bee queens can express the switch point in the absence of workers experimentally demonstrates queen control of a key life-history event in eusocial insects. In addition, we found no evidence that workers affect the timing of the switch point either directly or indirectly via providing cues to queens, suggesting that workers do not fully express their interests in queen–worker conflicts over colony life history. PMID:23637392

  8. Life history as a constraint on plasticity: developmental timing is correlated with phenotypic variation in birds

    PubMed Central

    Snell-Rood, E C; Swanson, E M; Young, R L

    2015-01-01

    Understanding why organisms vary in developmental plasticity has implications for predicting population responses to changing environments and the maintenance of intraspecific variation. The epiphenotype hypothesis posits that the timing of development can constrain plasticity—the earlier alternate phenotypes begin to develop, the greater the difference that can result amongst the final traits. This research extends this idea by considering how life history timing shapes the opportunity for the environment to influence trait development. We test the prediction that the earlier an individual begins to actively interact with and explore their environment, the greater the opportunity for plasticity and thus variation in foraging traits. This research focuses on life history variation across four groups of birds using museum specimens and measurements from the literature. We reasoned that greater phenotypic plasticity, through either environmental effects or genotype-by-environment interactions in development, would be manifest in larger trait ranges (bills and tarsi) within species. Among shorebirds and ducks, we found that species with relatively shorter incubation times tended to show greater phenotypic variation. Across warblers and sparrows, we found little support linking timing of flight and trait variation. Overall, our results also suggest a pattern between body size and trait variation, consistent with constraints on egg size that might result in larger species having more environmental influences on development. Taken together, our results provide some support for the hypothesis that variation in life histories affects how the environment shapes development, through either the expression of plasticity or the release of cryptic genetic variation. PMID:26039409

  9. Life history predicts risk of species decline in a stochastic world.

    PubMed

    Van Allen, Benjamin G; Dunham, Amy E; Asquith, Christopher M; Rudolf, Volker H W

    2012-07-07

    Understanding what traits determine the extinction risk of species has been a long-standing challenge. Natural populations increasingly experience reductions in habitat and population size concurrent with increasing novel environmental variation owing to anthropogenic disturbance and climate change. Recent studies show that a species risk of decline towards extinction is often non-random across species with different life histories. We propose that species with life histories in which all stage-specific vital rates are more evenly important to population growth rate may be less likely to decline towards extinction under these pressures. To test our prediction, we modelled declines in population growth rates under simulated stochastic disturbance to the vital rates of 105 species taken from the literature. Populations with more equally important vital rates, determined using elasticity analysis, declined more slowly across a gradient of increasing simulated environmental variation. Furthermore, higher evenness of elasticity was significantly correlated with a reduced chance of listing as Threatened on the International Union for Conservation of Nature Red List. The relative importance of life-history traits of diverse species can help us infer how natural assemblages will be affected by novel anthropogenic and climatic disturbances.

  10. Life history predicts risk of species decline in a stochastic world

    PubMed Central

    Van Allen, Benjamin G.; Dunham, Amy E.; Asquith, Christopher M.; Rudolf, Volker H. W.

    2012-01-01

    Understanding what traits determine the extinction risk of species has been a long-standing challenge. Natural populations increasingly experience reductions in habitat and population size concurrent with increasing novel environmental variation owing to anthropogenic disturbance and climate change. Recent studies show that a species risk of decline towards extinction is often non-random across species with different life histories. We propose that species with life histories in which all stage-specific vital rates are more evenly important to population growth rate may be less likely to decline towards extinction under these pressures. To test our prediction, we modelled declines in population growth rates under simulated stochastic disturbance to the vital rates of 105 species taken from the literature. Populations with more equally important vital rates, determined using elasticity analysis, declined more slowly across a gradient of increasing simulated environmental variation. Furthermore, higher evenness of elasticity was significantly correlated with a reduced chance of listing as Threatened on the International Union for Conservation of Nature Red List. The relative importance of life-history traits of diverse species can help us infer how natural assemblages will be affected by novel anthropogenic and climatic disturbances. PMID:22398172

  11. We Love Our Public Schools: Art Teachers' Life Histories in a Time of Loss, Accountability, and New Commonalities

    ERIC Educational Resources Information Center

    Trafí-Prats, Laura; Woywod, Christine

    2013-01-01

    This article is a Teachers' Life History study that centers on the context derived from current policies and budget cuts implemented to public services and education in the city of Milwaukee, Wisconsin. It explores how these affect the lives, moral commitments, and social senses of pedagogy of three art education specialists who have developed…

  12. Direct and indirect genetic effects in life-history traits of flour beetles (Tribolium castaneum).

    PubMed

    Ellen, Esther D; Peeters, Katrijn; Verhoeven, Merel; Gols, Rieta; Harvey, Jeffrey A; Wade, Michael J; Dicke, Marcel; Bijma, Piter

    2016-01-01

    Indirect genetic effects (IGEs) are the basis of social interactions among conspecifics, and can affect genetic variation of nonsocial and social traits. We used flour beetles (Tribolium castaneum) of two phenotypically distinguishable populations to estimate genetic (co)variances and the effect of IGEs on three life-history traits: development time (DT), growth rate (GR), and pupal body mass (BM). We found that GR was strongly affected by social environment with IGEs accounting for 18% of the heritable variation. We also discovered a sex-specific social effect: male ratio in a group significantly affected both GR and BM; that is, beetles grew larger and faster in male-biased social environments. Such sex-specific IGEs have not previously been demonstrated in a nonsocial insect. Our results show that beetles that achieve a higher BM do so via a slower GR in response to social environment. Existing models of evolution in age-structured or stage-structured populations do not account for IGEs of social cohorts. It is likely that such IGEs have played a key role in the evolution of developmental plasticity shown by Tenebrionid larvae in response to density. Our results document an important source of genetic variation for GR, often overlooked in life-history theory.

  13. Symbiotic state influences life-history strategy of a clonal cnidarian

    PubMed Central

    Bingham, Brian L.; Dimond, James L.; Muller-Parker, Gisèle

    2014-01-01

    Along the North American Pacific coast, the common intertidal sea anemone Anthopleura elegantissima engages in facultative, flexible symbioses with Symbiodinium muscatinei (a dinoflagellate) and Elliptochloris marina (a chlorophyte). Determining how symbiotic state affects host fitness is essential to understanding the ecological significance of engaging in such flexible relationships with diverse symbionts. Fitness consequences of hosting S. muscatinei, E. marina or negligible numbers of either symbiont (aposymbiosis) were investigated by measuring growth, cloning by fission and gonad development after 8.5–11 months of sustained exposure to high, moderate or low irradiance under seasonal environmental conditions. Both symbiotic state and irradiance affected host fitness, leading to divergent life-history strategies. Moderate and high irradiances led to a greater level of gonad development in individuals hosting E. marina, while high irradiance and high summer temperature promoted cloning in individuals hosting S. muscatinei and reduced fitness of aposymbiotic anemones. Associating with S. muscatinei may contribute to the success of A. elegantissima as a spatial competitor on the high shore: (i) by offsetting the costs of living under high temperature and irradiance conditions, and (ii) by promoting a high fission rate and clonal expansion. Our results suggest that basic life-history characteristics of a clonal cnidarian can be affected by the identity of the endosymbionts it hosts. PMID:25009060

  14. Characterizing the early life history of an imperiled freshwater mussel (Ptychobranchus jonesi)

    USGS Publications Warehouse

    Mcleod, John; Jelks, Howard; Pursifull, Sandra; Johnson, Nathan A.

    2016-01-01

    Conservation of imperiled species is frequently challenged by insufficient knowledge of life history and the environmental factors that affect various life stages. The larvae (glochidia) of most freshwater mussels in the family Unionidae are obligate ectoparasites of fishes. We describe the early life history of the federally endangered Southern Kidneyshell, Ptychobranchus jonesi, and compare methods for estimating fecundity and conducting host trials on conglutinate-producing mussel species. Both the glochidial inoculation baths and direct feeding of conglutinates to Percina nigrofasciata, Etheostoma edwini, and Etheostoma fusiforme resulted in successful metamorphosis to the juvenile life stage. Ptychobranchus jonesi glochidia did not metamorphose on the 25 other species of fishes tested representing 11 families. Three juveniles were recovered from Gambusia holbrooki resulting in a metamorphosis rate < 1%. We characterize P. jonesi as a host fish specialist that fractionally releases conglutinates from late January to early June. Intact P. jonesi conglutinate resemble a simuliid fly larva attached to an egg, but the majority of conglutinates were released as segments representing separate egg-- or larva--mimics. Viability of glochidia encased within a conglutinate was > 90% for at least 5 days. Directly feeding conglutinates to fishes allowed us to estimate natural infestation rates and calculate average numbers of juveniles produced per conglutinate, unlike the traditional approach of infesting fish hosts using an inoculation bath. Each method for measuring fecundity produced similar estimates but the regression, which estimated fecundity based on the physical dimensions of each conglutinate or conglutinate segment, was most practical. The distribution information, coupled with early life history description and methods developed for determining fecundity and conducting host trials, may assist in the conservation of P. jonesi, specifically during recovery

  15. Life histories of female elementary teachers and their science/teacher role construction

    NASA Astrophysics Data System (ADS)

    Ramseur, Aletha Johnson

    The research conducted in this study focuses on life histories of female elementary teachers and their science/teacher role construction. Identity theorists argue that the self consists of a collection of identities founded on occupying a particular role. Who we are depends on the roles we occupy. These roles are often referred to as "role identities". In the case of these participants, many role identities (mother, wife, sibling, and teacher) exist. This study focuses primarily on their (science) teacher role identity. Literature on women's lives, as learners and teachers, suggest that women's experiences, currently and throughout history influenced their teacher role construction. There is however, little knowledge of women's lives as elementary teachers of science and the affect of their experiences, currently and throughout history, on their (science) teacher identity construction. Schools delineated by race, class, and gender relations, are similar to other sectors of society's, social and cultural spheres within which race, class, and gender identities are constructed. Using in-depth-interviews female elementary teachers were encouraged to actively reconstruct their life and work-life experiences focusing on family, school and science interactions. They addressed the intellectual and emotional connections between their life and work experiences by focusing on details of their past and present experiences and examining the meaning of those experiences. It was the scrutiny of these connections between their life and work experiences, the meaning derived from them and historical events, and the constraints imposed on their personal choices by broader power relations, such as those of class, race, and gender that informed why we teach, how we teach, and what we teach.

  16. Implications of ecological energetics and biophysical and developmental constraints for life history variation in dinosaurs

    SciTech Connect

    Dunham, A.E.; Overall, K.L.; Forster, C.A.; Porter, W.P.

    1988-01-01

    There has been much recent speculation concerning the nature of life history variation in dinosaurs (Case, 1978; Bakker, 1986; Horner, 1982, 1984a). The purpose of this paper is to review the data on dinosaur life histories and to examine the nature and magnitude of the demographic and physiological factors that must have constrained life history variation in this group. 145 refs., 8 figs., 3 tabs.

  17. Life history tactics shape amphibians' demographic responses to the North Atlantic Oscillation.

    PubMed

    Cayuela, Hugo; Joly, Pierre; Schmidt, Benedikt R; Pichenot, Julian; Bonnaire, Eric; Priol, Pauline; Peyronel, Olivier; Laville, Mathias; Besnard, Aurélien

    2017-02-25

    Over the last three decades, climate abnormalities have been reported to be involved in biodiversity decline by affecting population dynamics. A growing number of studies have shown that the North Atlantic Oscillation (NAO) influences the demographic parameters of a wide range of plant and animal taxa in different ways. Life history theory could help to understand these different demographic responses to the NAO. Indeed, theory states that the impact of weather variation on a species' demographic traits should depend on its position along the fast-slow continuum. In particular, it is expected that NAO would have a higher impact on recruitment than on adult survival in slow species while the opposite pattern is expected occur in fast species. To test these predictions, we used long-term capture-recapture datasets (more than 15,000 individuals marked from 1965-2015) on different surveyed populations of three amphibian species in Western Europe: Triturus cristatus, Bombina variegata and Salamandra salamandra. Despite substantial intraspecific variation, our study revealed that these three species differ in their position on a slow-fast gradient of pace of life. Our results also suggest that the differences in life history tactics influences amphibian responses to NAO fluctuations: adult survival was most affected by the NAO in the species with the fastest pace of life (T. cristatus), whereas recruitment was most impacted in species with a slower pace of life (B. variegata and S. salamandra). In the context of climate change, our findings suggest that the capacity of organisms to deal with future changes in NAO values could be closely linked to their position on the fast-slow continuum. This article is protected by copyright. All rights reserved.

  18. Counterfactuals and history: Contingency and convergence in histories of science and life.

    PubMed

    Hesketh, Ian

    2016-08-01

    This article examines a series of recent histories of science that have attempted to consider how science may have developed in slightly altered historical realities. These works have, moreover, been influenced by debates in evolutionary science about the opposing forces of contingency and convergence in regard to Stephen Jay Gould's notion of "replaying life's tape." The article argues that while the historians under analysis seem to embrace contingency in order to present their counterfactual narratives, for the sake of historical plausibility they are forced to accept a fairly weak role for contingency in shaping the development of science. It is therefore argued that Simon Conway Morris's theory of evolutionary convergence comes closer to describing the restrained counterfactual worlds imagined by these historians of science than does contingency.

  19. Nutritional physiology of life-history trade-offs: how food protein-carbohydrate content influences life-history traits in the wing-polymorphic cricket Gryllus firmus.

    PubMed

    Clark, Rebecca M; Zera, Anthony J; Behmer, Spencer T

    2015-01-15

    Although life-history trade-offs result from the differential acquisition and allocation of nutritional resources to competing physiological functions, many aspects of this topic remain poorly understood. Wing-polymorphic insects, which possess alternative morphs that trade off allocation to flight capability versus early reproduction, provide a good model system for exploring this topic. In this study, we used the wing-polymorphic cricket Gryllus firmus to test how expression of the flight capability versus reproduction trade-off was modified across a heterogeneous protein-carbohydrate nutritional landscape. Newly molted adult female long- and short-winged crickets were given one of 13 diets with different concentrations and ratios of protein and digestible carbohydrate; for each cricket, we measured consumption patterns, growth and allocation to reproduction (ovary mass) versus flight muscle maintenance (flight muscle mass and somatic lipid stores). Feeding responses in both morphs were influenced more by total macronutrient concentration than by protein-carbohydrate ratio, except at high-macronutrient concentration, where protein-carbohydrate balance was important. Mass gain tended to be greatest on protein-biased diets for both morphs, but was consistently lower across all diets for long-winged females. When long-winged females were fed high-carbohydrate foods, they accumulated greater somatic lipid stores; on high-protein foods, they accumulated greater somatic protein stores. Food protein-carbohydrate content also affected short-winged females (selected for early reproductive onset), which showed dramatic increases in ovary size, including ovarian stores of lipid and protein, on protein-biased foods. This is the first study to show how the concentration and ratio of dietary protein and carbohydrate affects consumption and allocation to key physiological features associated with the reproduction-dispersal life-history trade-off.

  20. A Course on Humanistic Creativity in Later Life: Literature Review, Case Histories, and Recommendations.

    ERIC Educational Resources Information Center

    Nuessel, Frank; Van Stewart, Arthur; Cedeno, Aristofanes

    2001-01-01

    Presents case histories of late-life creativity in literature (May Sarton), painting (Marcel Duchamp), music (Leos Janacek), dance (Martha Graham), and theatre (Jessica Tandy). Offers suggestions for a course on humanistic creativity in later life. (Contains 74 references.) (SK)

  1. Phylogenetic signal in primate behaviour, ecology and life history.

    PubMed

    Kamilar, Jason M; Cooper, Natalie

    2013-05-19

    Examining biological diversity in an explicitly evolutionary context has been the subject of research for several decades, yet relatively recent advances in analytical techniques and the increasing availability of species-level phylogenies, have enabled scientists to ask new questions. One such approach is to quantify phylogenetic signal to determine how trait variation is correlated with the phylogenetic relatedness of species. When phylogenetic signal is high, closely related species exhibit similar traits, and this biological similarity decreases as the evolutionary distance between species increases. Here, we first review the concept of phylogenetic signal and suggest how to measure and interpret phylogenetic signal in species traits. Second, we quantified phylogenetic signal in primates for 31 variables, including body mass, brain size, life-history, sexual selection, social organization, diet, activity budget, ranging patterns and climatic variables. We found that phylogenetic signal varies extensively across and even within trait categories. The highest values are exhibited by brain size and body mass, moderate values are found in the degree of territoriality and canine size dimorphism, while low values are displayed by most of the remaining variables. Our results have important implications for the evolution of behaviour and ecology in primates and other vertebrates.

  2. Juvenility in the context of life history theory.

    PubMed

    Hochberg, Z

    2008-06-01

    Homo sapiens is unique in having four prolonged and pronounced postnatal pre-adult life history stages: infancy, which lasts for 30-36 months and ends with weaning from breast feeding in traditional societies; childhood, which lasts for an additional 2-4 years and concludes in a degree of independence as regards protection and food provision; a juvenile stage of 3-4 years that terminates with readiness for sexual maturation; and adolescence, which lasts for 3-5 years and culminates in fertility. Juvenility implies two transitional periods which are only experienced by humans: a transition from childhood to juvenility and from juvenility to adolescence. Juvenility, "the age of reason and responsibility" and concrete operation, coincides with elementary school age and offers opportunities to prepare for the social complexity of adolescence. Here I define the transition to juvenility by three variables: adrenarche (the onset of adrenal androgen generation), growth pattern (decelerating from a linear childhood growth velocity) and adiposity rebound acceleration of body mass index. The data presented suggest that this period is endowed with programming/predictive adaptive responses of body composition to the environment.

  3. The Pain Management Life History Calendar: A Pilot Study.

    PubMed

    McDonald, Deborah Dillon; Barri, Caroline

    2015-08-01

    Pain management trajectory data that includes previous pain treatments, timing, changes, and outcomes provide crucial data for patients with chronic pain and their practitioners to use when discussing ways to optimize pain management regimens. The aim of this study was to test the use of the life history calendar method to identify pain treatments, treatment regimens, timing, and outcomes of the pain management trajectory of individuals with chronic pain, and to examine feasibility. A pilot, descriptive, methodological design was used. Settings included community-based sites such as congregate housing. Nineteen community-dwelling older adults with osteoarthritis (OA) pain of at least 1 year's duration participated. Participants were interviewed and asked to chronicle from the beginning of the OA pain to the present all of their pain treatments and treatment effects (pain outcomes and adverse events). Raters independently content analyzed the transcribed interviews to identify pain treatments, treatment groupings (regimens), and treatment effects on pain. Feasibility of patients reporting their pain management trajectories was content analyzed by identifying participant difficulty identifying pain treatments, treatment effects, treatment sequence; and difficulty discriminating between treatments, and between OA pain and other pain sources. Individual pain management trajectories were constructed that depicted chronological order of pain treatment regimens and treatment effects. Participants identified pain treatments, discriminate between treatments and between OA and other conditions, and identified treatment effects. Treatment sequence was identified, but more precise timing was generally not reported. Pain management trajectories could provide a helpful way for practitioners to discuss safe, efficacious pain management options with patients.

  4. Life history, diversity and distribution: A study of Japanese pteridophytes

    USGS Publications Warehouse

    Guo, Q.; Kato, Masako; Ricklefs, R.E.

    2003-01-01

    Many studies address the relationships between diversity or distribution and attributes of the physical environment. However, how these relationships are connected to variation in life history is poorly understood. This is particularly true in the case of pteridophytes. Japanese ferns and their allies comprise one of the best-known pteridophyte floras in the world. We analyzed ca 600 species of Japanese pteridophytes for which there is detailed information on distribution, reproduction, and chromosome number. Species richness was greatest in groups with a single reproductive mode (sexual, followed by apogamous), but distribution was greatest in species groups with multiple reproductive modes: sexual plus either sterile (irregular in meiosis) or apogamous. Geographical ranges varied greatly among species with small chromosome numbers but were uniformly small among species having high chromosome numbers. Seasonally green (mostly summer green) species had significantly larger distribution ranges than evergreen species. Endemic species had higher proportions of apogamy and sterility than non-endemic species. Seasonally green species had significantly larger distributional ranges, and a smaller proportion of species with apogamous reproduction, than evergreen species. There was no clear relationship between distribution and spore size, either among endemic species, non-endemic species, or all species combined. There was no relationship between spore size and chromosome number when all species were combined. However, positive relationships were detected within three of the nine largest genera, suggesting potential phylogenetic effects. We concluded that habitat availability, rather than dispersability, may be the limiting factor for the distribution of pteridophytes in Japan.

  5. Life history dictates fluorosis risk in a small mammal community

    SciTech Connect

    Rafferty, D.P.; Faulkner, B.; Lochmiller, R.L.; Qualls, C.W. Jr.; McBee, K.

    1995-12-31

    Dental lesions, due to fluorosis, previously have been reported in wild, male cotton rats (Sigmodon hispidus) on an abandoned oil refinery located at the Oklahoma Refining Company in Cyril, Oklahoma. This study was expanded to include examinations of the fulvous harvest mouse (Reithrodontomys fulvescens), house mouse (Mus musculus), prairie vole (Microtus ochrogaster), plains pocket gopher (Geomys bursarius), least shrew (Cryptotis parva), shorttailed shrew (Blarina brevicauda), and deer mouse (Peromyscus spp.) at this same site. A sample of each species was collected form the contaminated refining site and a reference site with no known contamination. The authors grossly scored dentition of lower and upper incisors, microscopically examined cellular aberrations in ameloblasts and ondontoblasts, and quantified femur fluoride levels. Alterations in the lower and upper incisors were common in prairie voles, whose incisors possessed striations and erosion of the enamel and appeared chalky white. Incisors of animals taken from the reference site were normal. Patterns in occurrence of fluorosis and degree of enamel erosion was examined relative to the life history characteristics of the species.

  6. Recovery from disordered eating: what life histories reveal.

    PubMed

    Redenbach, Joanna; Lawler, Jocalyn

    2003-08-01

    There are few studies seeking to understand the illness from the experiential perspective of a person who has recovered from an eating disorder. The clinical and research literature shows inconsistencies and varying degrees of support for the risk factors associated with eating disordered behaviour. It is important to note, however, that most contemporary research relies upon brief self-report questionnaires, which may be providing a fragmented picture of the behaviour. The focus of the current study is to gain a greater understanding of women's perceptions of developing, living with and recovering from an eating disorder. This study reports interviews with five former eating disorder sufferers who were recruited via an advertisement placed in an Eating Disorders Support Network newsletter. Life histories were gathered from each woman and the paper reports how these women perceive the origins of their illness and what event(s) lead to their recovery. Participants' narratives were analysed to elucidate themes pertaining to the lived experience of illness and recovery. The women talk about a lack of control of their lives and unrealistic family expectations as reasons for the development of their eating disordered behaviour. Recovery was very strongly related to self-determination and self-acceptance. Suggestions concerning new ways of conceptualising recovery from eating disordered behaviour are posited.

  7. Life history and environmental requirements of loggerhead turtles

    SciTech Connect

    Nelson, D.A.

    1988-08-01

    In the United States scattered nestings of loggerhead sea turtles (Caretta caretta) may occur in most of its range from Texas to Florida and Florida to New Jersey; however, nesting concentrations occur on coastal islands of North Carolina, South Carolina, and Georgia and on the coasts of Florida. The greatest portion of a loggerhead's life is spent in ocean and estuarine waters where it breeds in shallow waters adjacent to nesting beaches, feeds on a variety of fish and shellfish, and migrates generally north in the spring and summer and south in the fall and winter. The other part of its life is spent on coastal beaches where the female digs a nest, lays her eggs (average 120 eggs), the eggs hatch (in 46 to 65 days), and the hatchlings emerge from the nest as a group and orient seaward to become part of the aquatic system again. Nesting activity begins in the spring, peaks in midsummer, and declines until completion in late summer. A loggerhead female generally nests every other or every third year. Beach sand temperatures may affect nest site selection by females, the incubation time and hatching success of eggs, and the sex and emergence timing of hatchlings. Most management of sea turtles has been directed toward increasing hatching and hatchling success through predator control, egg relocation, and raising captive hatchlings. 183 refs.; 10 figs.; 3 tabs.

  8. Delayed life history effects, multilevel selection, and evolutionary trade-offs in the California tiger salamander.

    PubMed

    Searcy, Christopher A; Gray, Levi N; Trenham, Peter C; Shaffer, H Bradley

    2014-01-01

    Delayed life history effects (DLHEs) occur when fitness in one life stage affects fitness in subsequent life stages. Given their biphasic life cycle, pond-breeding amphibians provide a natural system for studying DLHEs, although these effects are not restricted to species with biphasic life histories. In this study, we used multiple mark-recapture techniques enabled by a large trapping array to monitor components of fitness and resulting DLHEs in a population of the endangered California tiger salamander (Ambystoma californiense). We found that DLHEs are prominent across all life stage transitions and that there is variation in whether selection acts primarily at the individual or cohort level. We also demonstrated that there is more than an order of magnitude variation in mean cohort fitness, providing tremendous variation for DLHEs to act upon. We documented an evolutionary trade-off between mass at emergence and date of emergence, which may play a role in maintaining the variation in mass (fitness) at emergence. A literature review revealed that such high levels of intercohort variation occur in many other pond-breeding amphibians, and that appropriately documenting the magnitude of intercohort variation requires long-term studies (roughly two population turnovers). Given the profound effect that DLHEs can have on population dynamics, quantifying intercohort variation in mean fitness and the level(s) at which selection acts will be very important for developing accurate models of population dynamics. In general, when developing models of population dynamics, more attention should be paid to variation in mean fitness and not just variation in total numbers.

  9. Effect of watermelon silver mottle virus on the life history and feeding preference of Thrips palmi.

    PubMed

    Chen, Wei-Te; Tseng, Chien-Hao; Tsai, Chi-Wei

    2014-01-01

    Thrips-borne tospoviruses cause numerous plant diseases that produce severe economic losses worldwide. In the disease system, thrips not only damage plants through feeding but also transmit causative agents of epidemics. In addition, thrips are infected with tospoviruses in the course of virus transmission. Most studies on the effect of tospoviruses on vector thrips have focused on the Tomato spotted wilt virus-Frankliniella occidentalis system. Thus, we focused on another thrips-borne tospovirus, Watermelon silver mottle virus (WSMoV), to examine the effect of virus infection on its vector, Thrips palmi. In this study, the direct and indirect effects of WSMoV on the life history traits and feeding preference of T. palmi were examined. The survival rate and developmental time of the WSMoV-infected larval thrips did not differ significantly from those of the virus-free thrips. Comparing the developmental time of larval thrips fed on the healthy plants, thrips-damaged plants, and thrips-inoculated plants (the WSMoV-infected plants caused by thrips feeding), feeding on the thrips-damaged plants reduced the developmental time, and the WSMoV infection in host plants partially canceled the effect of thrips damage on the developmental time. In addition, no significant variations between the virus-free and WSMoV-infected adult thrips regarding longevity and fecundity were observed. These results implied that WSMoV did not directly affect the life history traits of T. palmi, but the WSMoV infection indirectly affected the development of T. palmi through the virus-infected plants. Furthermore, feeding preference tests indicated that T. palmi preferred feeding on either the thrips-damaged plants or the thrips-inoculated plants to the healthy plants. The effect of tospoviruses on the life history and feeding preference of vector thrips might vary among host plants, virus species, vector species, and environmental factors.

  10. Effect of Watermelon Silver Mottle Virus on the Life History and Feeding Preference of Thrips palmi

    PubMed Central

    Chen, Wei-Te; Tseng, Chien-Hao; Tsai, Chi-Wei

    2014-01-01

    Thrips-borne tospoviruses cause numerous plant diseases that produce severe economic losses worldwide. In the disease system, thrips not only damage plants through feeding but also transmit causative agents of epidemics. In addition, thrips are infected with tospoviruses in the course of virus transmission. Most studies on the effect of tospoviruses on vector thrips have focused on the Tomato spotted wilt virus–Frankliniella occidentalis system. Thus, we focused on another thrips-borne tospovirus, Watermelon silver mottle virus (WSMoV), to examine the effect of virus infection on its vector, Thrips palmi. In this study, the direct and indirect effects of WSMoV on the life history traits and feeding preference of T. palmi were examined. The survival rate and developmental time of the WSMoV-infected larval thrips did not differ significantly from those of the virus-free thrips. Comparing the developmental time of larval thrips fed on the healthy plants, thrips-damaged plants, and thrips-inoculated plants (the WSMoV-infected plants caused by thrips feeding), feeding on the thrips-damaged plants reduced the developmental time, and the WSMoV infection in host plants partially canceled the effect of thrips damage on the developmental time. In addition, no significant variations between the virus-free and WSMoV-infected adult thrips regarding longevity and fecundity were observed. These results implied that WSMoV did not directly affect the life history traits of T. palmi, but the WSMoV infection indirectly affected the development of T. palmi through the virus-infected plants. Furthermore, feeding preference tests indicated that T. palmi preferred feeding on either the thrips-damaged plants or the thrips-inoculated plants to the healthy plants. The effect of tospoviruses on the life history and feeding preference of vector thrips might vary among host plants, virus species, vector species, and environmental factors. PMID:25010157

  11. Spatially varying selection shapes life history clines among populations of Drosophila melanogaster from sub-Saharan Africa

    PubMed Central

    Fabian, Daniel K.; Lack, Justin B.; Mathur, Vinayak; Schlötterer, Christian; Schmidt, Paul S.; Pool, John E.; Flatt, Thomas

    2015-01-01

    Clines in life history traits, presumably driven by spatially varying selection, are widespread. Major latitudinal clines have been observed, for example, in Drosophila melanogaster, an ancestrally tropical insect from Africa that has colonized temperate habitats on multiple continents. Yet, how geographic factors other than latitude, such as altitude or longitude, affect life history in this species remains poorly understood. Moreover, most previous work has been performed on derived European, American and Australian populations, but whether life history also varies predictably with geography in the ancestral Afro-tropical range has not been investigated systematically. Here, we have examined life history variation among populations of D. melanogaster from sub-Saharan Africa. Viability and reproductive diapause did not vary with geography, but body size increased with altitude, latitude and longitude. Early fecundity covaried positively with altitude and latitude, whereas lifespan showed the opposite trend. Examination of genetic variance-covariance matrices revealed geographic differentiation also in trade-off structure, and QST-FST analysis showed that life history differentiation among populations is likely shaped by selection. Together, our results suggest that geographic and/or climatic factors drive adaptive phenotypic differentiation among ancestral African populations and confirm the widely held notion that latitude and altitude represent parallel gradients. PMID:25704153

  12. A life history perspective on skin cancer and the evolution of skin pigmentation.

    PubMed

    Osborne, Daniel L; Hames, Raymond

    2014-01-01

    The ancestral state of human skin pigmentation evolved in response to high ultraviolet radiation (UVR) stress. Some argue that pigmentation evolved to limit folate photolysis, therein limiting neural tube defects. Pigmentation also protects against sunburn which decreases the efficiency of sweating and potentiates skin infection. Pigmentation increases the efficacy of skin as a barrier to infection. Skin cancer has been rejected or minimized as a selective pressure because it is believed to have little or no effect on mortality during reproductive years. This argument ignores evidence of human longevity as a derived life history trait and the adaptive value of investment in offspring and kin, particularly during the post-reproductive lifespan. Opponents argue that lifespan in prehistoric hunter-gatherers was too short to be relevant to the evolution of skin pigmentation. This argument is flawed in that it relies on estimates of longevity at birth rather than adolescence. When appropriate estimates are used, it is clear that human longevity has a deep evolutionary history. We use a life history perspective to demonstrate the value of skin pigmentation as an adaptation to skin cancer with the following points: UVR exposure increases dysregulation of gene expression in skin cells leading to immortal cell lines; cutaneous malignant melanoma (CMM) affects individuals throughout reproductive years; and lifespan was longer than has previously been acknowledged, providing the opportunity for kin selection. This hypothesis is not at odds with the folate or barrier hypotheses. We stress that the evolution of skin pigmentation is complex and is an ongoing process.

  13. Metabolic rate covaries with fitness and the pace of the life history in the field.

    PubMed

    Pettersen, Amanda K; White, Craig R; Marshall, Dustin J

    2016-05-25

    Metabolic rate reflects the 'pace of life' in every organism. Metabolic rate is related to an organism's capacity for essential maintenance, growth and reproduction-all of which interact to affect fitness. Although thousands of measurements of metabolic rate have been made, the microevolutionary forces that shape metabolic rate remain poorly resolved. The relationship between metabolic rate and components of fitness are often inconsistent, possibly because these fitness components incompletely map to actual fitness and often negatively covary with each other. Here we measure metabolic rate across ontogeny and monitor its effects on actual fitness (lifetime reproductive output) for a marine bryozoan in the field. We also measure key components of fitness throughout the entire life history including growth rate, longevity and age at the onset of reproduction. We found that correlational selection favours individuals with higher metabolic rates in one stage and lower metabolic rates in the other-individuals with similar metabolic rates in each developmental stage displayed the lowest fitness. Furthermore, individuals with the lowest metabolic rates lived for longer and reproduced more, but they also grew more slowly and took longer to reproduce initially. That metabolic rate is related to the pace of the life history in nature has long been suggested by macroevolutionary patterns but this study reveals the microevolutionary processes that probably generated these patterns.

  14. Seed germination and life history syndromes in the California chaparral

    USGS Publications Warehouse

    Keeley, J.E.

    1991-01-01

    Syndromes are life history responses that are correlated to environmental regimes and are shared by a group of species (Stebbins, 1974). In the California chaparral there are two syndromes contrasted by the timing of seedling recruitment relative to wildfires. One syndrome, here called the fire-recruiter or refractory seed syndrome, includes species (both resprouting and non-resprouting) which share the feature that the timing of seedling establishment is specialized to the first rainy season after fire. Included are woody, suffrutescent and annual life forms but no geophytes have this syndrome. These species are linked by the characteristic that their seeds have a dormancy which is readily broken by environmental stimuli such as intense heat shock or chemicals leached from charred wood. Such seeds are referred to as “refractory” and dormancy, in some cases, is due to seed coat impermeability (such seeds are commonly called hardseeded), but in other cases the mechanism is unknown. Seeds of some may require cold stratification and/or light in addition to fire related stimuli. In the absence of fire related cues, a portion or all of a species’ seed pool remains dormant. Most have locally dispersed seeds that persist in the soil seed bank until the site burns. Dispersal of propagules is largely during spring and summer which facilitates the avoidance of flowering and fruiting during the summer and fall drought. Within a life form (e.g., shrub, suffrutescent, etc.), the seeds of these species have less mass than those of species with non-refractory seeds and this possibly reflects the environmental favorableness of the postfire environment for seedling establishment. Regardless of when fire occurs, germination is normally delayed until late winter or early spring. In the absence of fire, or other disturbance, opportunities for population expansion are largely lacking for species with this syndrome. The other syndrome, here called the fire-resister or non

  15. Application of Diversity Indices to Quantify Early Life-History Diversity for Chinook Salmon

    SciTech Connect

    Johnson, Gary E.; Sather, Nichole K.; Skalski, John R.; Teel, David

    2014-03-01

    We developed an index of early life history diversity (ELHD) for Pacific salmon (Oncorhynchus spp.) Early life history diversity is the variation in morphological and behavioral traits expressed within and among populations by individual juvenile salmon during their downstream migration. A standard quantitative method does not exist for this prominent concept in salmon biology.

  16. Life History Theory and Social Deviance: The Mediating Role of Executive Function

    ERIC Educational Resources Information Center

    Wenner, C. J.; Bianchi, J.; Figueredo, A. J.; Rushton, J. Philippe; Jacobs, W. J.

    2013-01-01

    The present work examined predicted relations among Life History strategies, Executive Functions, socially antagonistic attitudes, socially antagonistic behaviors, and general intelligence. Life History (LH) theory predicts that Executive Functions and socially antagonistic attitudes and behaviors underpin an interrelated and coherent set of…

  17. The Treatment of Geological Time & the History of Life on Earth in High School Biology Textbooks

    ERIC Educational Resources Information Center

    Summers, Gerald; Decker, Todd; Barrow, Lloyd

    2007-01-01

    In spite of the importance of geological time in evolutionary biology, misconceptions about historical events in the history of life on Earth are common. Glenn (1990) has documented a decline from 1960 to 1989 in the amount of space devoted to the history of life in high school earth science textbooks, but we are aware of no similar study in…

  18. Consilience and Life History Theory: From Genes to Brain to Reproductive Strategy

    ERIC Educational Resources Information Center

    Figueredo, Aurelio Jose; Vasquez, Geneva; Brumbach, Barbara H.; Schneider, Stephanie M. R.; Sefcek, Jon A.; Tal, Ilanit R.; Hill, Dawn; Wenner, Christopher J.; Jacobs, W. Jake

    2006-01-01

    We describe an integrated theory of individual differences that traces the behavioral development of life history from genes to brain to reproductive strategy. We provide evidence that a single common factor, the K-Factor, underpins a variety of life-history parameters, including an assortment of sexual, reproductive, parental, familial, and…

  19. Deformation history and load sequence effects on cumulative fatigue damage and life predictions

    NASA Astrophysics Data System (ADS)

    Colin, Julie

    Fatigue loading seldom involves constant amplitude loading. This is especially true in the cooling systems of nuclear power plants, typically made of stainless steel, where thermal fluctuations and water turbulent flow create variable amplitude loads, with presence of mean stresses and overloads. These complex loading sequences lead to the formation of networks of microcracks (crazing) that can propagate. As stainless steel is a material with strong deformation history effects and phase transformation resulting from plastic straining, such load sequence and variable amplitude loading effects are significant to its fatigue behavior and life predictions. The goal of this study was to investigate the effects of cyclic deformation on fatigue behavior of stainless steel 304L as a deformation history sensitive material and determine how to quantify and accumulate fatigue damage to enable life predictions under variable amplitude loading conditions for such materials. A comprehensive experimental program including testing under fully-reversed, as well as mean stress and/or mean strain conditions, with initial or periodic overloads, along with step testing and random loading histories was conducted on two grades of stainless steel 304L, under both strain-controlled and load-controlled conditions. To facilitate comparisons with a material without deformation history effects, similar tests were also carried out on aluminum 7075-T6. Experimental results are discussed, including peculiarities observed with stainless steel behavior, such as a phenomenon, referred to as secondary hardening characterized by a continuous increase in the stress response in a strain-controlled test and often leading to runout fatigue life. Possible mechanisms for secondary hardening observed in some tests are also discussed. The behavior of aluminum is shown not to be affected by preloading, whereas the behavior of stainless steel is greatly influenced by prior loading. Mean stress relaxation in

  20. Validation of Temperature Histories for Structural Steel Welds Using Estimated Heat-Affected-Zone Edges

    DTIC Science & Technology

    2016-10-12

    Estimated Heat -Affected-Zone Edges October 12, 2016 Approved for public release; distribution is unlimited. S.G. LambrakoS Center for Computational Materials...PAGES 17. LIMITATION OF ABSTRACT Validation of Temperature Histories for Structural Steel Welds Using Estimated Heat -Affected-Zone Edges S.G. Lambrakos...experimentally measured estimates of the heat -affected-zone edge to examine the consistency of calculated temperature histories for steel welds. 12-10-2016 NRL

  1. Life history traits to predict biogeographic species distributions in bivalves

    NASA Astrophysics Data System (ADS)

    Montalto, V.; Rinaldi, A.; Sarà, G.

    2015-10-01

    Organismal fecundity ( F) and its relationship with body size (BS) are key factors in predicting species distribution under current and future scenarios of global change. A functional trait-based dynamic energy budget (FT-DEB) is proposed as a mechanistic approach to predict the variation of F and BS as function of environmental correlates using two marine bivalves as model species ( Mytilus galloprovincialis and Brachidontes pharaonis). Validation proof of model skill (i.e., degree of correspondence between model predictions and field observations) and stationarity (i.e., ability of a model generated from data collected at one place/time to predict processes at another place/time) was provided to test model performance in predicting the bivalve distribution throughout the 22 sites in the Central Mediterranean Sea under local conditions of food density and body temperature. Model skill and stationarity were tested through the estimate of commission (i.e., proportion of species' absences predicted present) and omission (i.e., proportion of presences predicted absent) errors of predictions by comparing mechanistic predicted vs. observed F and BS values throughout the study area extrapolated by lab experiments and literature search. The resulting relationship was reliable for both species, and body size and fecundity were highly correlated in M. galloprovincialis compared to B. pharaonis; FT-DEB showed correct predictions of presence in more than 75 % of sites, and the regression between BS predicted vs. observed was highly significant in both species. Whilst recognising the importance of biotic interactions in shaping the distribution of species, our FT-DEB approach provided reliable quantitative estimates of where our species had sufficient F to support local populations or suggesting reproductive failure. Mechanistically, estimating F and BS as key traits of species life history can also be addressed within a broader, scale-dependent context that surpasses the

  2. Life history traits to predict biogeographic species distributions in bivalves.

    PubMed

    Montalto, V; Rinaldi, A; Sarà, G

    2015-10-01

    Organismal fecundity (F) and its relationship with body size (BS) are key factors in predicting species distribution under current and future scenarios of global change. A functional trait-based dynamic energy budget (FT-DEB) is proposed as a mechanistic approach to predict the variation of F and BS as function of environmental correlates using two marine bivalves as model species (Mytilus galloprovincialis and Brachidontes pharaonis). Validation proof of model skill (i.e., degree of correspondence between model predictions and field observations) and stationarity (i.e., ability of a model generated from data collected at one place/time to predict processes at another place/time) was provided to test model performance in predicting the bivalve distribution throughout the 22 sites in the Central Mediterranean Sea under local conditions of food density and body temperature. Model skill and stationarity were tested through the estimate of commission (i.e., proportion of species' absences predicted present) and omission (i.e., proportion of presences predicted absent) errors of predictions by comparing mechanistic predicted vs. observed F and BS values throughout the study area extrapolated by lab experiments and literature search. The resulting relationship was reliable for both species, and body size and fecundity were highly correlated in M. galloprovincialis compared to B. pharaonis; FT-DEB showed correct predictions of presence in more than 75 % of sites, and the regression between BS predicted vs. observed was highly significant in both species. Whilst recognising the importance of biotic interactions in shaping the distribution of species, our FT-DEB approach provided reliable quantitative estimates of where our species had sufficient F to support local populations or suggesting reproductive failure. Mechanistically, estimating F and BS as key traits of species life history can also be addressed within a broader, scale-dependent context that surpasses the

  3. Searching for a life history approach to salmon escapement management

    USGS Publications Warehouse

    Knudsen, E.E.; Symmes, E.W.; Margraf, F.J.

    2003-01-01

    A number of Pacific salmon populations have already been lost and many others throughout the range are in various states of decline. Recent research has documented that Pacific salmon carcasses serve as a key delivery vector of marine-derived nutrients into the freshwater portions of their ecosystems. This nutrient supply plays a critical biological feedback role in salmon sustainability by supporting juvenile salmon production. We first demonstrate how nutrient feedback potential to juvenile production may be unaccounted for in spawner-recruit models of populations under long-term exploitation. We then present a heuristic, life history-based, spreadsheet survival model that incorporates salmon carcass-driven nutrient feedback to the freshwater components of the salmon ecosystem. The productivity of a hypothetical coho salmon population was simulated using rates from the literature for survival from spawner to egg, egg to fry, fry to smolt, and smolt to adult. The effects of climate variation and nutrient feedback on survival were incorporated, as were density-dependent effects of the numbers of spawners and fry on freshwater survival of eggs and juveniles. The unexploited equilibrium population was subjected to 100 years of 20, 40, 60, and 80% harvest. Each harvest scenario greater than 20% brought the population to a reduced steady state, regardless of generous compensatory survival at low population sizes. Increasing harvest reduced the positive effects of nutrient contributions to population growth. Salmon researchers should further explore this modeling approach for establishing escapement goals. Given the importance of nutrient feedback, managers should strive for generous escapements that support nutrient rebuilding, as well as egg deposition, to ensure strong future salmon production.

  4. Social learning improves survivorship at a life-history transition.

    PubMed

    Manassa, R P; McCormick, M I

    2013-04-01

    During settlement, one of the main threats faced by individuals relates to their ability to detect and avoid predators. Information on predator identities can be gained either through direct experience or from the observation and/or interaction with others, a process known as social learning. In this form of predator recognition, less experienced individuals learn from experienced members within the social group, without having to directly interact with a predator. In this study, we examined the role of social learning in predator recognition in relation to the survival benefits for the damselfish, Pomacentrus wardi, during their settlement transition. Specifically, our experiments aimed to determine if P. wardi are capable of transmitting the recognition of the odour of a predator, Pseudochromis fuscus, to conspecifics. The experiment also examined whether there was a difference in the rate of survival between individuals that directly learnt the predator odour and those which acquired the information through social learning compared to naïve individuals. Results show that naïve P. wardi are able to learn a predator's identity from experienced individuals via social learning. Furthermore, survival between individuals that directly learnt the predator's identity and those that learnt through social learning did not significantly differ, with fish from both treatments surviving at least five times better than controls. These results demonstrate that experience may play a vital role in determining the outcome of predator-prey interactions, highlighting that social learning improves the ability of prey to avoid and/or escape predation at a life-history transition.

  5. Integration of manatee life-history data and population modeling

    USGS Publications Warehouse

    Eberhardt, L.L.; O'Shea, Thomas J.; O'Shea, Thomas J.; Ackerman, B.B.; Percival, H. Franklin

    1995-01-01

    Aerial counts and the number of deaths have been a major focus of attention in attempts to understand the population status of the Florida manatee (Trichechus manatus latirostris). Uncertainties associated with these data have made interpretation difficult. However, knowledge of manatee life-history attributes increased and now permits the development of a population model. We describe a provisional model based on the classical approach of Lotka. Parameters in the model are based on data from'other papers in this volume and draw primarily on observations from the Crystal River, Blue Spring, and Adantic Coast areas. The model estimates X (the finite rate ofincrease) at each study area, and application ofthe delta method provides estimates of variance components and partial derivatives ofX with respectto key input parameters (reproduction, adult survival, and early survival). In some study areas, only approximations of some parameters are available. Estimates of X and coefficients of variation (in parentheses) of manatees were 1.07 (0.009) in the Crystal River, 1.06 (0.012) at Blue Spring, and 1.01 (0.012) on the Atlantic Coast. Changing adult survival has a major effect on X. Early-age survival has the smallest effect. Bootstrap comparisons of population growth estimates from trend counts in the Crystal River and at Blue Spring and the reproduction and survival data suggest that the higher, observed rates from counts are probably not due to chance. Bootstrapping for variance estimates based on reproduction and survival data from manatees at Blue Spring and in the Crystal River provided estimates of X, adult survival, and rates of reproduction that were similar to those obtained by other methods. Our estimates are preliminary and suggestimprovements for future data collection and analysis. However, results support efforts to reduce mortality as the most effective means to promote the increased growth necessary for the eventual recovery of the Florida manatee

  6. Stochastic population dynamics in populations of western terrestrial garter snakes with divergent life histories

    USGS Publications Warehouse

    Miller, David A.; Clark, W.R.; Arnold, S.J.; Bronikowski, A.M.

    2011-01-01

    Comparative evaluations of population dynamics in species with temporal and spatial variation in life-history traits are rare because they require long-term demographic time series from multiple populations. We present such an analysis using demographic data collected during the interval 1978-1996 for six populations of western terrestrial garter snakes (Thamnophis elegans) from two evolutionarily divergent ecotypes. Three replicate populations from a slow-living ecotype, found in mountain meadows of northeastern California, were characterized by individuals that develop slowly, mature late, reproduce infrequently with small reproductive effort, and live longer than individuals of three populations of a fast-living ecotype found at lakeshore locales. We constructed matrix population models for each of the populations based on 8-13 years of data per population and analyzed both deterministic dynamics based on mean annual vital rates and stochastic dynamics incorporating annual variation in vital rates. (1) Contributions of highly variable vital rates to fitness (??s) were buffered against the negative effects of stochastic variation, and this relationship was consistent with differences between the meadow (M-slow) and lakeshore (L-fast) ecotypes. (2) Annual variation in the proportion of gravid females had the greatest negative effect among all vital rates on ?? s. The magnitude of variation in the proportion of gravid females and its effect on ??s was greater in M-slow than L-fast populations. (3) Variation in the proportion of gravid females, in turn, depended on annual variation in prey availability, and its effect on ??s was 4- 23 times greater in M-slow than L-fast populations. In addition to differences in stochastic dynamics between ecotypes, we also found higher mean mortality rates across all age classes in the L-fast populations. Our results suggest that both deterministic and stochastic selective forces have affected the evolution of divergent life-history

  7. Do early life factors affect the development of knee osteoarthritis in later life: a narrative review.

    PubMed

    Antony, Benny; Jones, Graeme; Jin, Xingzhong; Ding, Changhai

    2016-09-13

    Osteoarthritis (OA) mainly affects older populations; however, it is possible that early life factors contribute to the development of OA in later life. The aim of this review is to describe the association between childhood or early adulthood risk factors and knee pain, structural imaging markers and development of knee OA in later life. A narrative overview of the literature synthesising the findings of literature retrieved from searches of computerised databases and manual searches was conducted. We found that only a few studies have explored the long-term effect of childhood or early adulthood risk factors on the markers of joint health that predispose people to OA or joint symptoms. High body mass index (BMI) and/or overweight status from childhood to adulthood were independently related to knee pain and OA in later life. The findings regarding the association between strenuous physical activity and knee structures in young adults are still conflicting. However, a favourable effect of moderate physical activity and fitness on knee structures is reported. Childhood physical activity and performance measures had independent beneficial effects on knee structures including knee cartilage in children and young adults. Anterior knee pain syndrome in adolescence could lead to the development of patellofemoral knee OA in the late 40s. Furthermore, weak evidence suggests that childhood malalignment, socioeconomic status and physical abuse are associated with OA in later life. The available evidence suggests that early life intervention may prevent OA in later life.

  8. Influences on Bythotrephes longimanus life-history characteristics in the Great Lakes

    USGS Publications Warehouse

    Pothoven, Steven A.; Vanderploeg, Henry A.; Warner, David M.; Schaeffer, Jeffrey S.; Ludsin, Stuart A.; Claramunt, Randall M.; Nalepa, Thomas F.

    2012-01-01

    We compared Bythotrephes population demographics and dynamics to predator (planktivorous fish) and prey (small-bodied crustacean zooplankton) densities at a site sampled through the growing season in Lakes Michigan, Huron, and Erie. Although seasonal average densities of Bythotrephes were similar across lakes (222/m2 Erie, 247/m2 Huron, 162/m2 Michigan), temporal trends in abundance differed among lakes. In central Lake Erie where Bythotrephes' prey assemblage was dominated by small individuals (60%), where planktivorous fish densities were high (14,317/ha), and where a shallow water column limited availability of a deepwater refuge, the Bythotrephes population was characterized by a small mean body size, large broods with small neonates, allocation of length increases mainly to the spine rather than to the body, and a late summer population decline. By contrast, in Lake Michigan where Bythotrephes' prey assemblage was dominated by large individuals (72%) and planktivorous fish densities were lower (5052/ha), the Bythotrephes population was characterized by a large mean body size (i.e., 37–55% higher than in Erie), small broods with large neonates, nearly all growth in body length occurring between instars 1 and 2, and population persistence into fall. Life-history characteristics in Lake Huron tended to be intermediate to those found in Lakes Michigan and Erie, reflecting lower overall prey and predator densities (1224/ha) relative to the other lakes. Because plasticity in life history can affect interactions with other species, our findings point to the need to understand life-history variation among Great Lakes populations to improve our ability to model the dynamics of these ecosystems.

  9. A continuum of life histories in deep-sea demersal fishes

    NASA Astrophysics Data System (ADS)

    Drazen, Jeffrey C.; Haedrich, Richard L.

    2012-03-01

    It is generally perceived that all deep-sea fishes have great longevity, slow growth, and low reproductive output in comparison to shelf dwelling species. However, such a dichotomy is too simplistic because some fishes living on continental slopes are relatively fecund and fast growing, important considerations in respect to the management of expanding deep-sea fisheries. We tested two hypotheses that might explain variation in life history attributes of commercially exploited demersal fishes: (1) phylogeny best explains the differences because deep-sea species are often in different families from shelf dwelling ones and, alternatively, (2) environmental factors affecting individual life history attributes that change with depth account for the observed variation. Our analysis was based on 40 species from 9 orders, including all major commercially exploited deep-sea fishes and several phylogenetically related shelf species. Depth of occurrence correlated significantly with age at 50% maturity increasing linearly with depth (r2=0.46), while the von Bertalanffy growth coefficient, maximum fecundity and potential rate of population increase declined significantly and exponentially with depth (r2=0.41, 0.25 and 0.53, respectively). These trends were still significant when phylogenetically independent contrasts were applied. The trends were also consistent with similar slopes amongst members of the order Gadiformes and the order Scorpaeniformes. Reduced temperatures, predation pressure, food availability, or metabolic rates may all contribute to such changes with depth. Regardless of the mechanisms, by analyzing a suite of fishes from the shelves to the slope the present analysis has shown that rather than a simple dichotomy between deep-sea fishes and shelf fishes there is a continuum of life history attributes in fishes which correlate strongly with depth of occurrence.

  10. Temperature treatments during larval development reveal extensive heritable and plastic variation in gene expression and life history traits.

    PubMed

    Kvist, Jouni; Wheat, Christopher W; Kallioniemi, Eveliina; Saastamoinen, Marjo; Hanski, Ilkka; Frilander, Mikko J

    2013-02-01

    Little is known about variation in gene expression that affects life history traits in wild populations of outcrossing species. Here, we analyse heritability of larval development traits and associated variation in gene expression in the Glanville fritillary butterfly (Melitaea cinxia) across three ecologically relevant temperatures. We studied the development of final-instar larvae, which is greatly affected by temperature, and during which stage larvae build up most of the resources for adult life. Larval development time and weight gain varied significantly among families sampled from hundreds of local populations, indicating substantial heritable variation segregating in the large metapopulation. Global gene expression analysis using common garden-reared F2 families revealed that 42% of the >8000 genes surveyed exhibited significant variation among families, 39% of the genes showed significant variation between the temperature treatments, and 18% showed a significant genotype-by-environment interaction. Genes with large family and temperature effects included larval serum protein and cuticle-binding protein genes, and the expression of these genes was closely correlated with the rate of larval development. Significant expression variation in these same categories of genes has previously been reported among adult butterflies originating from newly established versus old local populations, supporting the notion of a life history syndrome put forward based on ecological studies and involving larval development and adult dispersal capacity. These findings suggest that metapopulation dynamics in heterogeneous environments maintain heritable gene expression variation that affects the regulation of life history traits.

  11. Human evolution, life history theory, and the end of biological reproduction.

    PubMed

    Last, Cadell

    2014-01-01

    Throughout primate history there have been three major life history transitions towards increasingly delayed sexual maturation and biological reproduction, as well as towards extended life expectancy. Monkeys reproduce later and live longer than do prosimians, apes reproduce later and live longer than do monkeys, and humans reproduce later and live longer than do apes. These life history transitions are connected to increased encephalization. During the last life history transition from apes to humans, increased encephalization co-evolved with increased dependence on cultural knowledge for energy acquisition. This led to a dramatic pressure for more energy investment in growth over current biological reproduction. Since the industrial revolution socioeconomic development has led to even more energy being devoted to growth over current biological reproduction. I propose that this is the beginning of an ongoing fourth major primate life history transition towards completely delayed biological reproduction and an extension of the evolved human life expectancy. I argue that the only fundamental difference between this primate life history transition and previous life history transitions is that this transition is being driven solely by cultural evolution, which may suggest some deeper evolutionary transition away from biological evolution is already in the process of occurring.

  12. Community history affects the predictability of microbial ecosystem development.

    PubMed

    Pagaling, Eulyn; Strathdee, Fiona; Spears, Bryan M; Cates, Michael E; Allen, Rosalind J; Free, Andrew

    2014-01-01

    Microbial communities mediate crucial biogeochemical, biomedical and biotechnological processes, yet our understanding of their assembly, and our ability to control its outcome, remain poor. Existing evidence presents conflicting views on whether microbial ecosystem assembly is predictable, or inherently unpredictable. We address this issue using a well-controlled laboratory model system, in which source microbial communities colonize a pristine environment to form complex, nutrient-cycling ecosystems. When the source communities colonize a novel environment, final community composition and function (as measured by redox potential) are unpredictable, although a signature of the community's previous history is maintained. However, when the source communities are pre-conditioned to their new habitat, community development is more reproducible. This situation contrasts with some studies of communities of macro-organisms, where strong selection under novel environmental conditions leads to reproducible community structure, whereas communities under weaker selection show more variability. Our results suggest that the microbial rare biosphere may have an important role in the predictability of microbial community development, and that pre-conditioning may help to reduce unpredictability in the design of microbial communities for biotechnological applications.

  13. Community history affects the predictability of microbial ecosystem development

    PubMed Central

    Pagaling, Eulyn; Strathdee, Fiona; Spears, Bryan M; Cates, Michael E; Allen, Rosalind J; Free, Andrew

    2014-01-01

    Microbial communities mediate crucial biogeochemical, biomedical and biotechnological processes, yet our understanding of their assembly, and our ability to control its outcome, remain poor. Existing evidence presents conflicting views on whether microbial ecosystem assembly is predictable, or inherently unpredictable. We address this issue using a well-controlled laboratory model system, in which source microbial communities colonize a pristine environment to form complex, nutrient-cycling ecosystems. When the source communities colonize a novel environment, final community composition and function (as measured by redox potential) are unpredictable, although a signature of the community's previous history is maintained. However, when the source communities are pre-conditioned to their new habitat, community development is more reproducible. This situation contrasts with some studies of communities of macro-organisms, where strong selection under novel environmental conditions leads to reproducible community structure, whereas communities under weaker selection show more variability. Our results suggest that the microbial rare biosphere may have an important role in the predictability of microbial community development, and that pre-conditioning may help to reduce unpredictability in the design of microbial communities for biotechnological applications. PMID:23985743

  14. Early life triclocarban exposure during lactation affects neonate rat survival.

    PubMed

    Kennedy, Rebekah C M; Menn, Fu-Min; Healy, Laura; Fecteau, Kellie A; Hu, Pan; Bae, Jiyoung; Gee, Nancy A; Lasley, Bill L; Zhao, Ling; Chen, Jiangang

    2015-01-01

    Triclocarban (3,4,4'-trichlorocarbanilide; TCC), an antimicrobial used in bar soaps, affects endocrine function in vitro and in vivo. This study investigates whether TCC exposure during early life affects the trajectory of fetal and/or neonatal development. Sprague Dawley rats were provided control, 0.2% weight/weight (w/w), or 0.5% w/w TCC-supplemented chow through a series of 3 experiments that limited exposure to critical growth periods: gestation, gestation and lactation, or lactation only (cross-fostering) to determine the susceptible windows of exposure for developmental consequences. Reduced offspring survival occurred when offspring were exposed to TCC at concentrations of 0.2% w/w and 0.5% w/w during lactation, in which only 13% of offspring raised by 0.2% w/w TCC dams survived beyond weaning and no offspring raised by 0.5% w/w TCC dams survived to this period. In utero exposure status had no effect on survival, as all pups nursed by control dams survived regardless of their in utero exposure status. Microscopic evaluation of dam mammary tissue revealed involution to be a secondary outcome of TCC exposure rather than a primary effect of compound administration. The average concentration of TCC in the milk was almost 4 times that of the corresponding maternal serum levels. The results demonstrate that gestational TCC exposure does not affect the ability of dams to carry offspring to term but TCC exposure during lactation has adverse consequences on the survival of offspring although the mechanism of reduced survival is currently unknown. This information highlights the importance of evaluating the safety of TCC application in personal care products and the impacts during early life exposure.

  15. Early Life Triclocarban Exposure During Lactation Affects Neonate Rat Survival

    PubMed Central

    Kennedy, Rebekah C. M.; Menn, Fu-Min; Healy, Laura; Fecteau, Kellie A.; Hu, Pan; Bae, Jiyoung; Gee, Nancy A.; Lasley, Bill L.; Zhao, Ling

    2015-01-01

    Triclocarban (3,4,4′-trichlorocarbanilide; TCC), an antimicrobial used in bar soaps, affects endocrine function in vitro and in vivo. This study investigates whether TCC exposure during early life affects the trajectory of fetal and/or neonatal development. Sprague Dawley rats were provided control, 0.2% weight/weight (w/w), or 0.5% w/w TCC-supplemented chow through a series of 3 experiments that limited exposure to critical growth periods: gestation, gestation and lactation, or lactation only (cross-fostering) to determine the susceptible windows of exposure for developmental consequences. Reduced offspring survival occurred when offspring were exposed to TCC at concentrations of 0.2% w/w and 0.5% w/w during lactation, in which only 13% of offspring raised by 0.2% w/w TCC dams survived beyond weaning and no offspring raised by 0.5% w/w TCC dams survived to this period. In utero exposure status had no effect on survival, as all pups nursed by control dams survived regardless of their in utero exposure status. Microscopic evaluation of dam mammary tissue revealed involution to be a secondary outcome of TCC exposure rather than a primary effect of compound administration. The average concentration of TCC in the milk was almost 4 times that of the corresponding maternal serum levels. The results demonstrate that gestational TCC exposure does not affect the ability of dams to carry offspring to term but TCC exposure during lactation has adverse consequences on the survival of offspring although the mechanism of reduced survival is currently unknown. This information highlights the importance of evaluating the safety of TCC application in personal care products and the impacts during early life exposure. PMID:24803507

  16. Ecoimmunology and microbial ecology: Contributions to avian behavior, physiology, and life history.

    PubMed

    Evans, Jessica K; Buchanan, Katherine L; Griffith, Simon C; Klasing, Kirk C; Addison, BriAnne

    2017-02-01

    Bacteria have had a fundamental impact on vertebrate evolution not only by affecting the evolution of the immune system, but also generating complex interactions with behavior and physiology. Advances in molecular techniques have started to reveal the intricate ways in which bacteria and vertebrates have coevolved. Here, we focus on birds as an example system for understanding the fundamental impact bacteria have had on the evolution of avian immune defenses, behavior, physiology, reproduction and life histories. The avian egg has multiple characteristics that have evolved to enable effective defense against pathogenic attack. Microbial risk of pathogenic infection is hypothesized to vary with life stage, with early life risk being maximal at either hatching or fledging. For adult birds, microbial infection risk is also proposed to vary with habitat and life stage, with molt inducing a period of increased vulnerability. Bacteria not only play an important role in shaping the immune system as well as trade-offs with other physiological systems, but also for determining digestive efficiency and nutrient uptake. The relevance of avian microbiomes for avian ecology, physiology and behavior is highly topical and will likely impact on our understanding of avian welfare, conservation, captive breeding as well as for our understanding of the nature of host-microbe coevolution.

  17. Social systems and life-history characteristics of mongooses.

    PubMed

    Schneider, Tilman C; Kappeler, Peter M

    2014-02-01

    The diversity of extant carnivores provides valuable opportunities for comparative research to illuminate general patterns of mammalian social evolution. Recent field studies on mongooses (Herpestidae), in particular, have generated detailed behavioural and demographic data allowing tests of assumptions and predictions of theories of social evolution. The first studies of the social systems of their closest relatives, the Malagasy Eupleridae, also have been initiated. The literature on mongooses was last reviewed over 25 years ago. In this review, we summarise the current state of knowledge on the social organisation, mating systems and social structure (especially competition and cooperation) of the two mongoose families. Our second aim is to evaluate the contributions of these studies to a better understanding of mammalian social evolution in general. Based on published reports or anecdotal information, we can classify 16 of the 34 species of Herpestidae as solitary and nine as group-living; there are insufficient data available for the remainder. There is a strong phylogenetic signal of sociality with permanent complex groups being limited to the genera Crossarchus, Helogale, Liberiictis, Mungos, and Suricata. Our review also indicates that studies of solitary and social mongooses have been conducted within different theoretical frameworks: whereas solitary species and transitions to gregariousness have been mainly investigated in relation to ecological determinants, the study of social patterns of highly social mongooses has instead been based on reproductive skew theory. In some group-living species, group size and composition were found to determine reproductive competition and cooperative breeding through group augmentation. Infanticide risk and inbreeding avoidance connect social organisation and social structure with reproductive tactics and life histories, but their specific impact on mongoose sociality is still difficult to evaluate. However, the level

  18. Genetic analysis of life-history constraint and evolution in a wild ungulate population.

    PubMed

    Morrissey, Michael B; Walling, Craig A; Wilson, Alastair J; Pemberton, Josephine M; Clutton-Brock, Tim H; Kruuk, Loeske E B

    2012-04-01

    Trade-offs among life-history traits are central to evolutionary theory. In quantitative genetic terms, trade-offs may be manifested as negative genetic covariances relative to the direction of selection on phenotypic traits. Although the expression and selection of ecologically important phenotypic variation are fundamentally multivariate phenomena, the in situ quantification of genetic covariances is challenging. Even for life-history traits, where well-developed theory exists with which to relate phenotypic variation to fitness variation, little evidence exists from in situ studies that negative genetic covariances are an important aspect of the genetic architecture of life-history traits. In fact, the majority of reported estimates of genetic covariances among life-history traits are positive. Here we apply theory of the genetics and selection of life histories in organisms with complex life cycles to provide a framework for quantifying the contribution of multivariate genetically based relationships among traits to evolutionary constraint. We use a Bayesian framework to link pedigree-based inference of the genetic basis of variation in life-history traits to evolutionary demography theory regarding how life histories are selected. Our results suggest that genetic covariances may be acting to constrain the evolution of female life-history traits in a wild population of red deer Cervus elaphus: genetic covariances are estimated to reduce the rate of adaptation by about 40%, relative to predicted evolutionary change in the absence of genetic covariances. Furthermore, multivariate phenotypic (rather than genetic) relationships among female life-history traits do not reveal this constraint.

  19. Life history variation in Barents Sea fish: implications for sensitivity to fishing in a changing environment.

    PubMed

    Wiedmann, Magnus A; Primicerio, Raul; Dolgov, Andrey; Ottesen, Camilla A M; Aschan, Michaela

    2014-09-01

    Under exploitation and environmental change, it is essential to assess the sensitivity and vulnerability of marine ecosystems to such stress. A species' response to stress depends on its life history. Sensitivity to harvesting is related to the life history "fast-slow" continuum, where "slow" species (i.e., large, long lived, and late maturing) are expected to be more sensitive to fishing than "fast" ones. We analyze life history traits variation for all common fish species in the Barents Sea and rank fishes along fast-slow gradients obtained by ordination analyses. In addition, we integrate species' fast-slow ranks with ecosystem survey data for the period 2004-2009, to assess life history variation at the community level in space and time. Arctic fishes were smaller, had shorter life spans, earlier maturation, larger offspring, and lower fecundity than boreal ones. Arctic fishes could thus be considered faster than the boreal species, even when body size was corrected for. Phylogenetically related species possessed similar life histories. Early in the study period, we found a strong spatial gradient, where members of fish assemblages in the southwestern Barents Sea displayed slower life histories than in the northeast. However, in later, warmer years, the gradient weakened caused by a northward movement of boreal species. As a consequence, the northeast experienced increasing proportions of slower fish species. This study is a step toward integrating life history traits in ecosystem-based areal management. On the basis of life history traits, we assess the fish sensitivity to fishing, at the species and community level. We show that climate warming promotes a borealization of fish assemblages in the northeast, associated with slower life histories in that area. The biology of Arctic species is still poorly known, and boreal species that now establish in the Arctic are fishery sensitive, which calls for cautious ecosystem management of these areas.

  20. Life history variation in Barents Sea fish: implications for sensitivity to fishing in a changing environment

    PubMed Central

    Wiedmann, Magnus A; Primicerio, Raul; Dolgov, Andrey; Ottesen, Camilla A M; Aschan, Michaela

    2014-01-01

    Under exploitation and environmental change, it is essential to assess the sensitivity and vulnerability of marine ecosystems to such stress. A species’ response to stress depends on its life history. Sensitivity to harvesting is related to the life history “fast–slow” continuum, where “slow” species (i.e., large, long lived, and late maturing) are expected to be more sensitive to fishing than “fast” ones. We analyze life history traits variation for all common fish species in the Barents Sea and rank fishes along fast–slow gradients obtained by ordination analyses. In addition, we integrate species’ fast–slow ranks with ecosystem survey data for the period 2004–2009, to assess life history variation at the community level in space and time. Arctic fishes were smaller, had shorter life spans, earlier maturation, larger offspring, and lower fecundity than boreal ones. Arctic fishes could thus be considered faster than the boreal species, even when body size was corrected for. Phylogenetically related species possessed similar life histories. Early in the study period, we found a strong spatial gradient, where members of fish assemblages in the southwestern Barents Sea displayed slower life histories than in the northeast. However, in later, warmer years, the gradient weakened caused by a northward movement of boreal species. As a consequence, the northeast experienced increasing proportions of slower fish species. This study is a step toward integrating life history traits in ecosystem-based areal management. On the basis of life history traits, we assess the fish sensitivity to fishing, at the species and community level. We show that climate warming promotes a borealization of fish assemblages in the northeast, associated with slower life histories in that area. The biology of Arctic species is still poorly known, and boreal species that now establish in the Arctic are fishery sensitive, which calls for cautious ecosystem management of

  1. Life history determines genetic structure and evolutionary potential of host–parasite interactions

    PubMed Central

    Barrett, Luke G.; Thrall, Peter H.; Burdon, Jeremy J.; Linde, Celeste C.

    2009-01-01

    Measures of population genetic structure and diversity of disease-causing organisms are commonly used to draw inferences regarding their evolutionary history and potential to generate new variation in traits that determine interactions with their hosts. Parasite species exhibit a range of population structures and life-history strategies, including different transmission modes, life-cycle complexity, off-host survival mechanisms and dispersal ability. These are important determinants of the frequency and predictability of interactions with host species. Yet the complex causal relationships between spatial structure, life history and the evolutionary dynamics of parasite populations are not well understood. We demonstrate that a clear picture of the evolutionary potential of parasitic organisms and their demographic and evolutionary histories can only come from understanding the role of life history and spatial structure in influencing population dynamics and epidemiological patterns. PMID:18947899

  2. Time-varying exposure and the impact of stressful life events on onset of affective disorder.

    PubMed

    Wainwright, Nicholas W J; Surtees, Paul G

    2002-07-30

    Stressful life events are now established as risk factors for the onset of affective disorder but few studies have investigated time-varying exposure effects. Discrete (grouped) time survival methods provide a flexible framework for evaluating multiple time-dependent covariates and time-varying covariate effects. Here, we use these methods to investigate the time-varying influence of life events on the onset of affective disorder. Various straightforward time-varying exposure models are compared, involving one or more (stepped) time-dependent covariates and time-dependent covariates constructed or estimated according to exponential decay. These models are applied to data from two quite different studies. The first, a small scale interviewer-based longitudinal study (n = 180) concerned with affective disorder onset following loss (or threat of loss) event experiences. The second, a questionnaire assessment as part of an ongoing population study (n = 3353), provides a history of marital loss events and of depressive disorder onset. From the first study the initial impact of loss events was found to decay with a half-life of 5 weeks. Psychological coping strategy was found to modify vulnerability to the adverse effects of these events. The second study revealed that while men had a lower immediate risk of disorder onset following loss event experience their risk period was greater than for women. Time-varying exposure effects were well described by the appropriate use of simple time-dependent covariates.

  3. Genetic and life-history traits associated with the distribution of prophages in bacteria

    PubMed Central

    Touchon, Marie; Bernheim, Aude; Rocha, Eduardo PC

    2016-01-01

    Nearly half of the sequenced bacteria are lysogens and many of their prophages encode adaptive traits. Yet, the variables driving prophage distribution remain undetermined. We identified 2246 prophages in complete bacterial genomes to study the genetic and life-history traits associated with lysogeny. While optimal growth temperatures and average cell volumes were not associated with lysogeny, prophages were more frequent in pathogens and in bacteria with small minimal doubling times. Their frequency also increased with genome size, but only for genomes smaller than 6 Mb. The number of spacers in CRISPR-Cas systems and the frequency of type III systems were anticorrelated with prophage frequency, but lysogens were more likely to encode type I and type II systems. The minimal doubling time was the trait most correlated with lysogeny, followed by genome size and pathogenicity. We propose that bacteria with highly variable growth rates often encounter lower opportunity costs for lysogeny relative to lysis. These results contribute to explain the paucity of temperate phages in certain bacterial clades and of bacterial lysogens in certain environments. They suggest that genetic and life-history traits affect the contributions of temperate phages to bacterial genomes. PMID:27015004

  4. Sexual systems and dwarf males in barnacles: integrating life history and sex allocation theories.

    PubMed

    Yamaguchi, Sachi; Yusa, Yoichi; Sawada, Kota; Takahashi, Satoshi

    2013-03-07

    Barnacles, which are sedentary marine crustaceans, have diverse sexual systems that include simultaneous hermaphroditism, androdioecy (coexistence of hermaphrodites and males) and dioecy (females and males). In dioecious and androdioecious species, the males are very small and are thus called dwarf males. These sexual systems are defined by two factors: sex allocation of non-dwarf individuals and the presence or absence of dwarf males. We constructed an ESS model treating sex allocation and life history simultaneously to explain sexual systems in barnacles. We analyzed the evolutionarily stable size-dependent resource allocation strategy to male reproductive function, female reproductive function and growth in non-dwarf barnacles, and the ESS proportion of dwarf males, under conditions of varying mortality and food availability. Sex allocation in non-dwarf individuals (hermaphrodites or females) is affected by mate availability and the proportion of dwarf males. When hermaphrodites appear, all hermaphrodites become protandric simultaneous hermaphrodites. Furthermore, high mortality and poor resource availability favor dwarf males because of their early maturation and weakened sperm competition. In conclusion, we showed that combining sex allocation and life history theories is a useful way to understand various sexual systems in barnacles and perhaps in other organisms as well.

  5. Correlated contemporary evolution of life history traits in New Zealand Chinook salmon, Oncorhynchus tshawytscha.

    PubMed

    Kinnison, M T; Quinn, T P; Unwin, M J

    2011-03-01

    Size at age and age at maturity are important life history traits, affecting individual fitness and population demography. In salmon and other organisms, size and growth rate are commonly considered cues for maturation and thus age at maturity may or may not evolve independently of these features. Recent concerns surrounding the potential phenotypic and demographic responses of populations facing anthropogenic disturbances, such as climate change and harvest, place a premium on understanding the evolutionary genetic basis for evolution in size at age and age at maturity. In this study, we present the findings from a set of common-garden rearing experiments that empirically assess the heritable basis of phenotypic divergence in size at age and age at maturity in Chinook salmon (Oncorhynchus tshawytscha) populations introduced to New Zealand. We found consistent evidence of heritable differences among populations in both size at age and age at maturity, often corresponding to patterns observed in the wild. Populations diverged in size and growth profiles, even when accounting for eventual age at maturation. By contrast, most, but not all, cases of divergence in age at maturity were driven by the differences in size or growth rate rather than differences in the threshold relationship linking growth rate and probability of maturation. These findings help us understand how life histories may evolve through trait interactions in populations exposed to natural and anthropogenic disturbances, and how we might best detect such evolution.

  6. Genetic and life-history traits associated with the distribution of prophages in bacteria.

    PubMed

    Touchon, Marie; Bernheim, Aude; Rocha, Eduardo Pc

    2016-11-01

    Nearly half of the sequenced bacteria are lysogens and many of their prophages encode adaptive traits. Yet, the variables driving prophage distribution remain undetermined. We identified 2246 prophages in complete bacterial genomes to study the genetic and life-history traits associated with lysogeny. While optimal growth temperatures and average cell volumes were not associated with lysogeny, prophages were more frequent in pathogens and in bacteria with small minimal doubling times. Their frequency also increased with genome size, but only for genomes smaller than 6 Mb. The number of spacers in CRISPR-Cas systems and the frequency of type III systems were anticorrelated with prophage frequency, but lysogens were more likely to encode type I and type II systems. The minimal doubling time was the trait most correlated with lysogeny, followed by genome size and pathogenicity. We propose that bacteria with highly variable growth rates often encounter lower opportunity costs for lysogeny relative to lysis. These results contribute to explain the paucity of temperate phages in certain bacterial clades and of bacterial lysogens in certain environments. They suggest that genetic and life-history traits affect the contributions of temperate phages to bacterial genomes.

  7. A conceptual life-history model for pallid and shovelnose sturgeon

    USGS Publications Warehouse

    Wildhaber, Mark L.; DeLonay, Aaron J.; Papoulias, Diana M.; Galat, David L.; Jacobson, Robert B.; Simpkins, Darin G.; Braaten, P. J.; Korschgen, Carl E.; Mac, Michael J.

    2007-01-01

    Intensive management of the Missouri and Mississippi Rivers has resulted in dramatic physical changes to these rivers. These changes have been implicated as causative agents in the decline of pallid sturgeon. The pallid sturgeon, federally listed as endangered, is endemic to the turbid waters of the Missouri River and the Lower Mississippi River. The sympatric shovelnose sturgeon historically was more common and widespread than the pallid sturgeon. Habitat alteration, river regulation, pollution, and over-harvest have resulted in the now predictable patterns of decline and localized extirpation of sturgeon across species and geographic areas. Symptomatic of this generalized pattern of decline is poor reproductive success, and low or no recruitment of wild juveniles to the adult population. The purpose of this report is to introduce a conceptual life-history model of the factors that affect reproduction, growth, and survival of shovelnose and pallid sturgeons. The conceptual model provided here was developed to organize the understanding about the complex life history of Scaphirhynchus sturgeons. It was designed to be used for communication, planning, and to provide the structure for a population-forecasting model. These models are intended to be dynamic and responsive to new information and changes in river management, thereby providing scientists, stakeholders, and managers with ways to improve understanding of the effects of management actions on the ecological requirements of Scaphirhynchus sturgeons. As new scientific knowledge becomes available, it could be included in the model in many ways at various integration levels.

  8. EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS

    PubMed Central

    ZUHARAH, Wan Fatma; AHBIRAMI, Rattanam; DIENG, Hamady; THIAGALETCHUMI, Maniam; FADZLY, Nik

    2016-01-01

    Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity) and eggs hatchability (fertility) in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors. PMID:27253746

  9. Optimality models of phage life history and parallels in disease evolution.

    PubMed

    Bull, J J

    2006-08-21

    Optimality models constitute one of the simplest approaches to understanding phenotypic evolution. Yet they have shortcomings that are not easily evaluated in most organisms. Most importantly, the genetic basis of phenotype evolution is almost never understood, and phenotypic selection experiments are rarely possible. Both limitations can be overcome with bacteriophages. However, phages have such elementary life histories that few phenotypes seem appropriate for optimality approaches. Here we develop optimality models of two phage life history traits, lysis time and host range. The lysis time models show that the optimum is less sensitive to differences in host density than suggested by earlier analytical work. Host range evolution is approached from the perspective of whether the virus should avoid particular hosts, and the results match optimal foraging theory: there is an optimal "diet" in which host types are either strictly included or excluded, depending on their infection qualities. Experimental tests of both models are feasible, and phages provide concrete illustrations of many ways that optimality models can guide understanding and explanation. Phage genetic systems already support the perspective that lysis time and host range can evolve readily and evolve without greatly affecting other traits, one of the main tenets of optimality theory. The models can be extended to more general properties of infection, such as the evolution of virulence and tissue tropism.

  10. Life history strategies of fish species and biodiversity in eastern USA streams

    USGS Publications Warehouse

    Meador, Michael R.; Brown, Larry M.

    2015-01-01

    Predictive models have been used to determine fish species that occur less frequently than expected (decreasers) and those that occur more frequently than expected (increasers) in streams in the eastern U.S. Coupling life history traits with 51 decreaser and 38 increaser fish species provided the opportunity to examine potential mechanisms associated with predicted changes in fish species distributions in eastern streams. We assigned six life history traits – fecundity, longevity, maturation age, maximum total length, parental care, and spawning season duration – to each fish species. Decreaser species were significantly smaller in size and shorter-lived with reduced fecundity and shorter spawning seasons compared to increaser species. Cluster analysis of traits revealed correspondence with a life history model defining equilibrium (low fecundity, high parental care), opportunistic (early maturation, low parental care), and periodic (late maturation, high fecundity, low parental care) end-point strategies. Nearly 50 % of decreaser species were associated with an intermediate opportunistic-periodic strategy, suggesting that abiotic factors such as habitat specialization and streamflow alteration may serve as important influences on life history traits and strategies of decreaser species. In contrast, the percent of increaser species among life history strategy groups ranged from 21 to 32 %, suggesting that life history strategies of increaser species were more diverse than those of decreaser species. This study highlights the utility of linking life history theory to biodiversity to better understand mechanisms that contribute to fish species distributions in the eastern U.S.

  11. Early life trauma is associated with altered white matter integrity and affective control.

    PubMed

    Corbo, Vincent; Amick, Melissa A; Milberg, William P; McGlinchey, Regina E; Salat, David H

    2016-08-01

    Early life trauma (ELT) has been shown to impair affective control and attention well into adulthood. Neuroimaging studies have further shown that ELT was associated with decreased white matter integrity in the prefrontal areas in children and adults. However, no study to date has looked at the relationship between white matter integrity and affective control in individuals with and without a history of ELT. To examine this, we tested 240 Veterans with (ELT N = 80) and without (NoELT N = 160) a history of childhood sexual abuse, physical abuse or family violence. Affective control was measured with the Affective Go/No-Go (AGN) and attention was indexed with the Test of Variable Attention (TOVA). White matter integrity was measured using fractional anisotropy (FA). Results showed greater number of errors on the AGN in ELT compared to NoELT. There was no difference on the TOVA. While there were no mean differences in FA, there was an interaction between FA and reaction time to positive stimuli on the AGN where the ELT group showed a positive relationship between FA and reaction time in right frontal and prefrontal areas, whereas the NoELT group showed a negative or no association between FA and reaction time. This suggests that ELT may be associated with a distinct brain-behavior relationship that could be related to other determinants of FA than those present in healthy adults.

  12. The relationship between religion, illness and death in life histories of family members of children with life-threatening diseases.

    PubMed

    Bousso, Regina Szylit; Serafim, Taís de Souza; Misko, Maira Deguer

    2010-01-01

    This qualitative study aimed to get to know the relationship between the experiences of families of children with a life-threatening disease and their religion, illness and life histories. The methodological framework was based on Oral History. The data were collected through interviews and the participants were nine families from six different religions who had lived the experience of having a child with a life-threatening disease. The interviews, held with one or two family members, were transcribed, textualized and, through their analysis, the Vital Tone was elaborated, representing the moral synthesis of each narrative. Three dimensions of spirituality were related to illness and death in their life histories: a Higher Being with a healing power; Development and Maintenance of a Connection with God and Faith Encouraging Optimism. The narratives demonstrated the family's search to attribute meanings to their experiences, based on their religious beliefs.

  13. Life Form and Life History Explain Variation in Population Processes in a Grassland Community Invaded by Exotic Plants and Mammals

    PubMed Central

    Nelis, Lisa Castillo

    2012-01-01

    The existence of general characteristics of plant invasiveness is still debated. One reason we may not have found these characteristics is because we do not yet understand how processes underlying population dynamics contribute to community composition in invaded communities. Here I modify Ricker stock-recruitment models to parameterize processes important to community dynamics in an invaded grassland community: immigration, maximum intrinsic growth rate, self-regulation, and limitation by other species. I then used the parameterized models in a multi-species stochastic simulation to determine how processes affected long-term community dynamics. By parameterizing the models using the frequency of the 18 most common species in the grassland, I determined that life history and life form are stronger predictors of underlying processes than is native status. Immigration maintains exotic annual grasses and the dominant native perennial grass in the community. Growth rate maintains other perennial species. While the model mirrors the frequency of native species well, exotic species have lower observed than parameterized frequencies, suggesting that they are not reaching their potential frequency. These results, combined with results from past research, suggest that disturbance may be key to maintaining exotic species in the community. Here I showed that a continuous modified Ricker model fit discrete grassland frequency data well. This allowed me to model the dominant species in the community simultaneously and gain insight into the processes that determine community composition. PMID:22916178

  14. Dental development and life history in living African and Asian apes

    PubMed Central

    Kelley, Jay; Schwartz, Gary T.

    2009-01-01

    Life-history inference is an important aim of paleoprimatology, but life histories cannot be discerned directly from the fossil record. Among extant primates, the timing of many life-history attributes is correlated with the age at emergence of the first permanent molar (M1), which can therefore serve as a means to directly compare the life histories of fossil and extant species. To date, M1 emergence ages exist for only a small fraction of extant primate species and consist primarily of data from captive individuals, which may show accelerated dental eruption compared with free-living individuals. Data on M1 emergence ages in wild great apes exist for only a single chimpanzee individual, with data for gorillas and orangutans being anecdotal. This paucity of information limits our ability to make life-history inferences using the M1 emergence ages of extinct ape and hominin species. Here we report reliable ages at M1 emergence for the orangutan, Pongo pygmaeus (4.6 y), and the gorilla, Gorilla gorilla (3.8 y), obtained from the dental histology of wild-shot individuals in museum collections. These ages and the one reported age at M1 emergence in a free-living chimpanzee of approximately 4.0 y are highly concordant with the comparative life histories of these great apes. They are also consistent with the average age at M1 emergence in relation to the timing of life-history events in modern humans, thus confirming the utility of M1 emergence ages for life-history inference and providing a basis for making reliable life-history inferences for extinct apes and hominins. PMID:20080537

  15. Movies Bring History to Life. Take It from Experience.

    ERIC Educational Resources Information Center

    Sabato, George

    1992-01-01

    Contends that feature films can heighten student interest in history. Proposes having students create film presentations based on historical topics. Includes a model research unit on Roman civilization. (CFR)

  16. Prediction of extinction in plants: interaction of extrinsic threats and life history traits.

    PubMed

    Fréville, Hélène; McConway, Kevin; Dodd, Mike; Silvertown, Jonathan

    2007-10-01

    The global extinction of species proceeds through the erosion of local populations. Using a 60-year time series of annual sighting records of plant species, we studied the correlates of local extinction risk associated with a risk of species extinction in the Park Grass Experiment where plants received long-term exposure to nutrient enrichment, soil acidification, and reductions in habitat size. We used multivariate linear models to assess how extrinsic threats and life history traits influence extinction risk. We investigated effects of four extrinsic threats (nitrogen enrichment, productivity, acidification, and plot size) as well as 11 life history traits (month of earliest flowering, flowering duration, stress tolerance, ruderalness [plant species' ability to cope with habitat disturbance], plant height, diaspore mass, seed bank, life form, dispersal mode, apomixis [the ability for a species to reproduce asexuall through seeds], and mating system). Extinction risk was not influenced by plant family. All of the 11 life history traits except life form and all threat variables influenced extinction risk but always via interactions which typically involved one threat variable and one life history trait. We detected comparatively few significant interactions between life history traits, and the interacting traits compensated for each other. These results suggest that simple predictions about extinction risk based on species' traits alone will often fail. In contrast, understanding the interactions between extrinsic threats and life history traits will allow us to make more accurate predictions of extinctions.

  17. Environmental forcing on life history strategies: Evidence for multi-trophic level responses at ocean basin scales

    NASA Astrophysics Data System (ADS)

    Suryan, Robert M.; Saba, Vincent S.; Wallace, Bryan P.; Hatch, Scott A.; Frederiksen, Morten; Wanless, Sarah

    2009-04-01

    Variation in life history traits of organisms is thought to reflect adaptations to environmental forcing occurring from bottom-up and top-down processes. Such variation occurs not only among, but also within species, indicating demographic plasticity in response to environmental conditions. From a broad literature review, we present evidence for ocean basin- and large marine ecosystem-scale variation in intra-specific life history traits, with similar responses occurring among trophic levels from relatively short-lived secondary producers to very long-lived apex predators. Between North Atlantic and North Pacific Ocean basins, for example, species in the Eastern Pacific exhibited either later maturation, lower fecundity, and/or greater annual survival than conspecifics in the Western Atlantic. Parallel variations in life histories among trophic levels also occur in adjacent seas and between eastern vs. western ocean boundaries. For example, zooplankton and seabird species in cooler Barents Sea waters exhibit lower fecundity or greater annual survival than conspecifics in the Northeast Atlantic. Sea turtles exhibit a larger size and a greater reproductive output in the Western Pacific vs. Eastern Pacific. These examples provide evidence for food-web-wide modifications in life history strategies in response to environmental forcing. We hypothesize that such dichotomies result from frequency and amplitude shifts in resource availability over varying temporal and spatial scales. We review data that supports three primary mechanisms by which environmental forcing affects life history strategies: (1) food-web structure; (2) climate variability affecting the quantity and seasonality of primary productivity; (3) bottom-up vs. top-down forcing. These proposed mechanisms provide a framework for comparisons of ecosystem function among oceanic regions (or regimes) and are essential in modeling ecosystem response to climate change, as well as for creating dynamic ecosystem

  18. Environmental forcing on life history strategies: Evidence for multi-trophic level responses at ocean basin scales

    USGS Publications Warehouse

    Suryan, Robert M.; Saba, Vincent S.; Wallace, Bryan P.; Hatch, Scott A.; Frederiksen, Morten; Wanless, Sarah

    2009-01-01

    Variation in life history traits of organisms is thought to reflect adaptations to environmental forcing occurring from bottom-up and top-down processes. Such variation occurs not only among, but also within species, indicating demographic plasticity in response to environmental conditions. From a broad literature review, we present evidence for ocean basin- and large marine ecosystem-scale variation in intra-specific life history traits, with similar responses occurring among trophic levels from relatively short-lived secondary producers to very long-lived apex predators. Between North Atlantic and North Pacific Ocean basins, for example, species in the Eastern Pacific exhibited either later maturation, lower fecundity, and/or greater annual survival than conspecifics in the Western Atlantic. Parallel variations in life histories among trophic levels also occur in adjacent seas and between eastern vs. western ocean boundaries. For example, zooplankton and seabird species in cooler Barents Sea waters exhibit lower fecundity or greater annual survival than conspecifics in the Northeast Atlantic. Sea turtles exhibit a larger size and a greater reproductive output in the Western Pacific vs. Eastern Pacific. These examples provide evidence for food-web-wide modifications in life history strategies in response to environmental forcing. We hypothesize that such dichotomies result from frequency and amplitude shifts in resource availability over varying temporal and spatial scales. We review data that supports three primary mechanisms by which environmental forcing affects life history strategies: (1) food-web structure; (2) climate variability affecting the quantity and seasonality of primary productivity; (3) bottom-up vs. top-down forcing. These proposed mechanisms provide a framework for comparisons of ecosystem function among oceanic regions (or regimes) and are essential in modeling ecosystem response to climate change, as well as for creating dynamic ecosystem

  19. Cumulative Effects of Nutrient Enrichment and Elevated Temperature Compromise the Early Life History Stages of the Coral Acropora tenuis

    PubMed Central

    Noonan, Sam H. C.; Willis, Bette L.; Fabricius, Katharina E.; Negri, Andrew P.

    2016-01-01

    Inshore coral reefs are experiencing the combined pressures of excess nutrient availability associated with coastal activities and warming seawater temperatures. Both pressures are known to have detrimental effects on the early life history stages of hard corals, but studies of their combined effects on early demographic stages are lacking. We conducted a series of experiments to test the combined effects of nutrient enrichment (three levels) and elevated seawater temperature (up to five levels) on early life history stages of the inshore coral Acropora tenuis, a common species in the Indo-Pacific and Red Sea. Gamete fertilization, larval survivorship and larval settlement were all significantly reduced as temperature increased, but only fertilization was further affected by simultaneous nutrient enrichment. Combined high temperatures and nutrient enrichment affected fertilization in an additive manner, whereas embryo abnormalities increased synergistically. Higher than normal temperatures (32°C) increased coral juvenile growth rates 1.6-fold, but mortality also increased by 50%. The co-occurrence of nutrient enrichment with high temperatures reduced juvenile mortality to 36%, ameliorating temperature stress (antagonistic interaction). Overall, the types of effect (additive vs synergistic or antagonistic) and their magnitude varied among life stages. Gamete and embryo stages were more affected by temperature stress and, in some cases, also by nutrient enrichment than juveniles. The data suggest that coastal runoff events might exacerbate the impacts of warming temperatures on fertilization if these events co-occur during corals spawning. The cumulative impacts of simultaneous exposure to nutrient enrichment and elevated temperatures over all early life history stages increases the likelihood for failure of larval supply and recruitment for this coral species. Our results suggest that improving the water quality of river discharges into coastal areas might help to

  20. Emotional stress-reactivity and positive affect among college students: the role of depression history.

    PubMed

    O'Hara, Ross E; Armeli, Stephen; Boynton, Marcella H; Tennen, Howard

    2014-02-01

    Multiple theories posit that people with a history of depression are at higher risk for a depressive episode than people who have never experienced depression, which may be partly due to differences in stress-reactivity. In addition, both the dynamic model of affect and the broaden-and-build theory suggest that stress and positive affect interact to predict negative affect, but this moderation has never been tested in the context of depression history. The current study used multilevel modeling to examine these issues among 1,549 college students with or without a history of depression. Students completed a 30-day online diary study in which they reported daily their perceived stress, positive affect, and negative affect (including depression, anxiety, and hostility). On days characterized by higher than usual stress, students with a history of depression reported greater decreases in positive affect and greater increases in depressed affect than students with no history. Furthermore, the relations between daily stress and both depressed and anxious affect were moderated by daily positive affect among students with remitted depression. These results indicate that students with a history of depression show greater stress-reactivity even when in remission, which may place them at greater risk for recurrence. These individuals may also benefit more from positive affect on higher stress days despite being less likely to experience positive affect on such days. The current findings have various implications both clinically and for research on stress, mood, and depression. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  1. Source, Method, and Surmise: Quality of Life in History

    ERIC Educational Resources Information Center

    Jordan, Thomas E.

    2009-01-01

    The purpose of the essay is to demonstrate that study of quality of life can explore eras before our own. There are caches of social data as early as the seventeenth century, and there were people who attempted to formulate social circumstances close to today's concepts of quality of life. Data from England and Ireland are presented and analyzed.

  2. The influence of life-history strategy on genetic differentiation and lineage divergence in darters (Percidae: Etheostomatinae).

    PubMed

    Fluker, Brook L; Kuhajda, Bernard R; Harris, Phillip M

    2014-11-01

    Recent studies determined that darters with specialized breeding strategies can exhibit deep lineage divergence over fine geographic scales without apparent physical barriers to gene flow. However, the extent to which intrinsic characteristics interact with extrinsic factors to influence population divergence and lineage diversification in darters is not well understood. This study employed comparative phylogeographic and population genetic methods to investigate the influence of life history on gene flow, dispersal ability, and lineage divergence in two sympatric sister darters with differing breeding strategies. Our results revealed highly disparate phylogeographic histories, patterns of genetic structure, and dispersal abilities between the two species suggesting that life history may contribute to lineage diversification in darters, especially by limiting dispersal among large river courses. Both species also showed striking differences in demographic history, indicating that extrinsic factors differentially affected each species during the Pleistocene. Collectively, our results indicate that intrinsic and extrinsic factors have influenced levels of gene flow among populations within both species examined. However, we suggest that life-history strategy may play a more important role in lineage diversification in darters than previously appreciated, a finding that has potentially important implications for understanding diversification of the rich North American freshwater fish fauna.

  3. Life history change in response to fishing and an introduced predator in the East African cyprinid Rastrineobola argentea

    PubMed Central

    Sharpe, Diana M T; Wandera, Silvester B; Chapman, Lauren J

    2012-01-01

    Fishing and introduced species are among the most important stressors affecting freshwaters and can also be strong selective agents. We examined the combined effects of commercial fishing and an introduced predator (Nile perch, Lates niloticus) on life history traits in an African cyprinid fish (Rastrineobola argentea) native to the Lake Victoria basin in East Africa. To understand whether these two stressors have driven shifts in life history traits of R. argentea, we tested for associations between life history phenotypes and the presence/absence of stressors both spatially (across 10 Ugandan lakes) and temporally (over four decades in Lake Victoria). Overall, introduced Nile perch and fishing tended to be associated with a suite of life history responses in R. argentea, including: decreased body size, maturation at smaller sizes, and increased reproductive effort (larger eggs; and higher relative fecundity, clutch volume, and ovary weight). This is one of the first well-documented examples of fisheries-induced phenotypic change in a tropical, freshwater stock; the magnitude of which raises some concerns for the long-term sustainability of this fishery, now the most important (by mass) in Lake Victoria. PMID:23144655

  4. Life Stress and Family History for Depression: The Moderating Role of Past Depressive Episodes

    PubMed Central

    Monroe, Scott M.; Slavich, George M.; Gotlib, Ian H.

    2014-01-01

    Three of the most consistently reported and powerful predictors of depression are a recent major life event, a positive family history for depression, and a personal history of past depressive episodes. Little research, however, has evaluated the inter-relations among these predictors in depressed samples. Such information is descriptively valuable and potentially etiologically informative. In the present article we summarize the existing literature and test four predictions in a sample of 62 clinically depressed individuals: (1) participants who experienced a major life event prior to onset would be less likely than participants who did not experience a major life event to have a positive family history for depression; (2) participants with a recent major life event would have fewer lifetime episodes of depression than would participants without; (3) participants with a positive family history for depression would have more lifetime episodes of depression than would participants with a negative family history for depression; and (4) we would obtain a 3-way interaction in which participants with a positive family history and without a major life event would have the most lifetime episodes, whereas participants with a negative family history and a major life event would have the fewest lifetime episodes. The first three predictions were confirmed, and the fourth prediction partially confirmed. These novel findings begin to elucidate the complex relations among these three prominent risk factors for depression, and point to avenues of research that may help illuminate the origins of depressive episodes. PMID:24308926

  5. Life stress and family history for depression: the moderating role of past depressive episodes.

    PubMed

    Monroe, Scott M; Slavich, George M; Gotlib, Ian H

    2014-02-01

    Three of the most consistently reported and powerful predictors of depression are a recent major life event, a positive family history for depression, and a personal history of past depressive episodes. Little research, however, has evaluated the inter-relations among these predictors in depressed samples. Such information is descriptively valuable and potentially etiologically informative. In the present article we summarize the existing literature and test four predictions in a sample of 62 clinically depressed individuals: (1) participants who experienced a major life event prior to onset would be less likely than participants who did not experience a major life event to have a positive family history for depression; (2) participants with a recent major life event would have fewer lifetime episodes of depression than would participants without; (3) participants with a positive family history for depression would have more lifetime episodes of depression than would participants with a negative family history for depression; and (4) we would obtain a 3-way interaction in which participants with a positive family history and without a major life event would have the most lifetime episodes, whereas participants with a negative family history and a major life event would have the fewest lifetime episodes. The first three predictions were confirmed, and the fourth prediction partially confirmed. These novel findings begin to elucidate the complex relations among these three prominent risk factors for depression, and point to avenues of research that may help illuminate the origins of depressive episodes.

  6. Effects of Increased Flight on the Energetics and Life History of the Butterfly Speyeria mormonia

    PubMed Central

    Niitepõld, Kristjan; Boggs, Carol L.

    2015-01-01

    Movement uses resources that may otherwise be allocated to somatic maintenance or reproduction. How does increased energy expenditure affect resource allocation? Using the butterfly Speyeria mormonia, we tested whether experimentally increased flight affects fecundity, lifespan or flight capacity. We measured body mass (storage), resting metabolic rate and lifespan (repair and maintenance), flight metabolic rate (flight capacity), egg number and composition (reproduction), and food intake across the adult lifespan. The flight treatment did not affect body mass or lifespan. Food intake increased sufficiently to offset the increased energy expenditure. Total egg number did not change, but flown females had higher early-life fecundity and higher egg dry mass than control females. Egg dry mass decreased with age in both treatments. Egg protein, triglyceride or glycogen content did not change with flight or age, but some components tracked egg dry mass. Flight elevated resting metabolic rate, indicating increased maintenance costs. Flight metabolism decreased with age, with a steeper slope for flown females. This may reflect accelerated metabolic senescence from detrimental effects of flight. These effects of a drawdown of nutrients via flight contrast with studies restricting adult nutrient input. There, fecundity was reduced, but flight capacity and lifespan were unchanged. The current study showed that when food resources were abundant, wing-monomorphic butterflies living in a continuous meadow landscape resisted flight-induced stress, exhibiting no evidence of a flight-fecundity or flight-longevity trade-off. Instead, flight changed the dynamics of energy use and reproduction as butterflies adopted a faster lifestyle in early life. High investment in early reproduction may have positive fitness effects in the wild, as long as food is available. Our results help to predict the effect of stressful conditions on the life history of insects living in a changing world

  7. Bone morphologies and histories: Life course approaches in bioarchaeology.

    PubMed

    Agarwal, Sabrina C

    2016-01-01

    The duality of the skeleton as both a biological and cultural entity has formed the theoretical basis of bioarchaeology. In recent years bioarchaeological studies have stretched the early biocultural concept with the adoption of life course approaches in their study design and analyses, making a significant contribution to how we think about the role of postnatal plasticity. Life course theory is a conceptual framework used in several scientific fields of biology and the social sciences. Studies that emphasize life course approaches in the examination of bone morphology in the past are united in their interrogation of human life as a result of interrelated and cumulative events over not only the timeframe of individuals, but also over generations at the community level. This article provides an overview of the theoretical constructs that utilize the life course concept, and a discussion of the different ways these theories have been applied to thinking about trajectories of bone morphology in the past, specifically highlighting key recent studies that have used life course approaches to understand the influence of growth, stress, diet, activity, and aging on the skeleton. The goal of this article is to demonstrate the scope of contemporary bioarchaeological studies that illuminate the importance of environmental and behavioral influence on bone morphology. Understanding how trajectories of bone growth and morphology can be altered and shaped over the life course is critical not only for bioarchaeologists, but also researchers studying bone morphology in living nonhuman primates and fossil primate skeletons.

  8. Modeling effects of environmental change on wolf population dynamics, trait evolution, and life history.

    PubMed

    Coulson, Tim; MacNulty, Daniel R; Stahler, Daniel R; vonHoldt, Bridgett; Wayne, Robert K; Smith, Douglas W

    2011-12-02

    Environmental change has been observed to generate simultaneous responses in population dynamics, life history, gene frequencies, and morphology in a number of species. But how common are such eco-evolutionary responses to environmental change likely to be? Are they inevitable, or do they require a specific type of change? Can we accurately predict eco-evolutionary responses? We address these questions using theory and data from the study of Yellowstone wolves. We show that environmental change is expected to generate eco-evolutionary change, that changes in the average environment will affect wolves to a greater extent than changes in how variable it is, and that accurate prediction of the consequences of environmental change will probably prove elusive.

  9. Violence, teenage pregnancy, and life history : ecological factors and their impact on strategy-driven behavior.

    PubMed

    Copping, Lee T; Campbell, Anne; Muncer, Steven

    2013-06-01

    Guided by principles of life history strategy development, this study tested the hypothesis that sexual precocity and violence are influenced by sensitivities to local environmental conditions. Two models of strategy development were compared: The first is based on indirect perception of ecological cues through family disruption and the second is based on both direct and indirect perception of ecological stressors. Results showed a moderate correlation between rates of violence and sexual precocity (r = 0.59). Although a model incorporating direct and indirect effects provided a better fit than one based on family mediation alone, significant improvements were made by linking some ecological factors directly to behavior independently of strategy development. The models support the contention that violence and teenage pregnancy are part of an ecologically determined pattern of strategy development and suggest that while the family unit is critical in affecting behavior, individuals' direct experiences of the environment are also important.

  10. Chronic toxicity of ibuprofen to Daphnia magna: Effects on life history traits and population dynamics.

    PubMed

    Heckmann, Lars-Henrik; Callaghan, Amanda; Hooper, Helen L; Connon, Richard; Hutchinson, Thomas H; Maund, Steve J; Sibly, Richard M

    2007-08-01

    The non-steroidal anti-inflammatory drug (NSAID) ibuprofen (IB) is a widely used pharmaceutical that can be found in several freshwater ecosystems. Acute toxicity studies with Daphnia magna suggest that the 48h EC(50) (immobilisation) is 10-100 mgIBl(-1). However, there are currently no chronic IB toxicity data on arthropod populations, and the aquatic life impacts of such analgesic drugs are still undefined. We performed a 14-day exposure of D. magna to IB as a model compound (concentration range: 0, 20, 40 and 80 mgIBl(-1)) measuring chronic effects on life history traits and population performance. Population growth rate was significantly reduced at all IB concentrations, although survival was only affected at 80 mgIBl(-1). Reproduction, however, was affected at lower concentrations of IB (14-day EC(50) of 13.4 mgIBl(-1)), and was completely inhibited at the highest test concentration. The results from this study indicate that the long-term crustacean population consequences of a chronic IB exposure at environmentally realistic concentrations (ngl(-1) to microgl(-1)) would most likely be of minor importance. We discuss our results in relation to recent genomic studies, which suggest that the potential mechanism of toxicity in Daphnia is similar to the mode of action in mammals, where IB inhibits eicosanoid biosynthesis.

  11. Transient population dynamics: Relations to life history and initial population state

    USGS Publications Warehouse

    Koons, D.N.; Grand, J.B.; Zinner, B.; Rockwell, R.F.

    2005-01-01

    Most environments are variable and disturbances (e.g., hurricanes, fires) can lead to substantial changes in a population's state (i.e., age, stage, or size distribution). In these situations, the long-term (i.e., asymptotic) measure of population growth rate (??1) may inaccurately represent population growth in the short-term. Thus, we calculated the short-term (i.e., transient) population growth rate and its sensitivity to changes in the life-cycle parameters for three bird and three mammal species with widely varying life histories. Further, we performed these calculations for initial population states that spanned the entire range of possibilities. Variation in a population's initial net reproductive value largely explained the variation in transient growth rates and their sensitivities to changes in life-cycle parameters (all AICc ??? 6.67 units better than the null model, all R2 ??? 0.55). Additionally, the transient fertility and adult survival sensitivities tended to increase with the initial net reproductive value of the population, whereas the sub-adult survival sensitivity decreased. Transient population dynamics of long-lived, slow reproducing species were more variable and more different than asymptotic dynamics than they were for short-lived, fast reproducing species. Because ??1 can be a biased estimate of the actual growth rate in the short-term (e.g., 19% difference), conservation and wildlife biologists should consider transient dynamics when developing management plans that could affect a population's state, or whenever population state could be unstable.

  12. Life history trade-offs imposed by dragline use in two money spiders.

    PubMed

    Bonte, Dries; Verduyn, Lieselot; Braeckman, Bart P

    2016-01-01

    Trade-offs among life history traits are central to understanding the limits of adaptations to stress. In animals, virtually all decisions taken during life are expected to have downstream consequences. To what degree rare, but energy-demanding, decisions carry over to individual performance is rarely studied in arthropods. We used spiders as a model system to test how single investments in silk use - for dispersal or predator escape - affect individual performance. Silk produced for safe lines and as threads for ballooning is of the strongest kind and is energetically costly, especially when resources are limited. We induced dragline spinning in two species of money spider at similar quantities to that under natural conditions and tested trade-offs with lifespan and egg sac production under unlimited prey availability and a dietary restriction treatment. We demonstrate strong trade-offs between dragline spinning and survival and fecundity. Survival trade-offs were additive to those imposed by the dietary treatment, but a reduction in eggs produced after silk use was only prevalent under conditions where food was restricted during the spider's life. Because draglines are not recycled after their use for dispersal or predator escape, their spinning incurs substantial fitness costs in dispersal, especially in environments with prey limitation. Rare but energetically costly decisions related to dispersal or predator escape may thus carry over to adult performance and explain phenotypic heterogeneity in natural populations.

  13. Contrasting Responses to Harvesting and Environmental Drivers of Fast and Slow Life History Species

    PubMed Central

    Quetglas, Antoni; Rueda, Lucía; Alvarez-Berastegui, Diego; Guijarro, Beatriz; Massutí, Enric

    2016-01-01

    According to their main life history traits, organisms can be arranged in a continuum from fast (species with small body size, short lifespan and high fecundity) to slow (species with opposite characteristics). Life history determines the responses of organisms to natural and anthropogenic factors, as slow species are expected to be more sensitive than fast species to perturbations. Owing to their contrasting traits, cephalopods and elasmobranchs are typical examples of fast and slow strategies, respectively. We investigated the responses of these two contrasting strategies to fishing exploitation and environmental conditions (temperature, productivity and depth) using generalized additive models. Our results confirmed the foreseen contrasting responses of cephalopods and elasmobranchs to natural (environment) and anthropogenic (harvesting) influences. Even though a priori foreseen, we did expect neither the clear-cut differential responses between groups nor the homogeneous sensitivity to the same factors within the two taxonomic groups. Apart from depth, which affected both groups equally, cephalopods and elasmobranchs were exclusively affected by environmental conditions and fishing exploitation, respectively. Owing to its short, annual cycle, cephalopods do not have overlapping generations and consequently lack the buffering effects conferred by different age classes observed in multi-aged species such as elasmobranchs. We suggest that cephalopods are sensitive to short-term perturbations, such as seasonal environmental changes, because they lack this buffering effect but they are in turn not influenced by continuous, long-term moderate disturbances such as fishing because of its high population growth and turnover. The contrary would apply to elasmobranchs, whose multi-aged population structure would buffer the seasonal environmental effects, but they would display strong responses to uninterrupted harvesting due to its low population resilience. Besides

  14. Phosphorus-mediated changes in life history traits of the invasive New Zealand mudsnail (Potamopyrgus antipodarum).

    PubMed

    Tibbets, Teresa M; Krist, Amy C; Hall, Robert O; Riley, Leslie A

    2010-07-01

    Understanding the mechanisms that species use to succeed in new environments is vital to predicting the extent of invasive species impacts. Food quality is potentially important because it can affect population dynamics by affecting life history traits. The New Zealand mudsnail, Potamopyrgus antipodarum, is a worldwide invader. We examined how mudsnail growth rate and fecundity responded to the C:P ratio of algal food in laboratory conditions. Mudsnails fed low-P algae (C:P 1,119) grew more slowly, matured later, produced smaller offspring, and grew to a smaller adult size than snails reared on algae with high levels of P. A relatively small increase in algal C:P (203-270) significantly increased mudsnail age at maturity. We suggest that the relatively high body P requirements of mudsnails make them susceptible to allocation trade-offs between growth and reproduction under P-limited conditions. The elemental composition of algae varies greatly in nature, and over half of the rock biofilms in streams surveyed within the introduced range of mudsnails in the Greater Yellowstone Area had C:P ratios above which could potentially pose P limitation of life history traits. High growth rate and fecundity are common traits of many species that become invasive and are also associated with high-P demands. Therefore, fast-growing consumers with high P demands, such as mudsnails, are potentially more sensitive to P limitation suggesting that limitation of growth and reproduction by food quality is an important factor in understanding the resource demands of invasive species.

  15. Life-history and habitat features influence the within-river genetic structure of Atlantic salmon.

    PubMed

    Vähä, Juha-Pekka; Erkinaro, Jaakko; Niemelä, Eero; Primmer, Craig R

    2007-07-01

    Defining populations and identifying ecological and life-history characteristics affecting genetic structure is important for understanding species biology and hence, for managing threatened or endangered species or populations. In this study, populations of the world's largest indigenous Atlantic salmon (Salmo salar) stock were first inferred using model-based clustering methods, following which life-history and habitat variables best predicting the genetic diversity of populations were identified. This study revealed that natal homing of Atlantic salmon within the Teno River system is accurate at least to the tributary level. Generally, defining populations by main tributaries was observed to be a reasonable approach in this large river system, whereas in the mainstem of the river, the number of inferred populations was fewer than the number of distinct sampling sites. Mainstem and headwater populations were genetically more diverse and less diverged, while each tributary fostered a distinct population with high genetic differentiation and lower genetic diversity. Population structure and variation in genetic diversity among populations were poorly explained by geographical distance. In contrast, age-structure, as estimated by the proportion of multisea-winter spawners, was the most predictive variable in explaining the variation in the genetic diversity of the populations. This observation, being in agreement with theoretical predictions, emphasizes the essence of large multisea-winter females in maintaining the genetic diversity of populations. In addition, the unique genetic diversity of populations, as estimated by private allele richness, was affected by the ease of accessibility of a site, with more difficult to access sites having lower unique genetic diversity. Our results show that despite this species' high capacity for migration, tributaries foster relatively closed populations with little gene flow which will be important to consider when developing

  16. Contrasting Responses to Harvesting and Environmental Drivers of Fast and Slow Life History Species.

    PubMed

    Quetglas, Antoni; Rueda, Lucía; Alvarez-Berastegui, Diego; Guijarro, Beatriz; Massutí, Enric

    2016-01-01

    According to their main life history traits, organisms can be arranged in a continuum from fast (species with small body size, short lifespan and high fecundity) to slow (species with opposite characteristics). Life history determines the responses of organisms to natural and anthropogenic factors, as slow species are expected to be more sensitive than fast species to perturbations. Owing to their contrasting traits, cephalopods and elasmobranchs are typical examples of fast and slow strategies, respectively. We investigated the responses of these two contrasting strategies to fishing exploitation and environmental conditions (temperature, productivity and depth) using generalized additive models. Our results confirmed the foreseen contrasting responses of cephalopods and elasmobranchs to natural (environment) and anthropogenic (harvesting) influences. Even though a priori foreseen, we did expect neither the clear-cut differential responses between groups nor the homogeneous sensitivity to the same factors within the two taxonomic groups. Apart from depth, which affected both groups equally, cephalopods and elasmobranchs were exclusively affected by environmental conditions and fishing exploitation, respectively. Owing to its short, annual cycle, cephalopods do not have overlapping generations and consequently lack the buffering effects conferred by different age classes observed in multi-aged species such as elasmobranchs. We suggest that cephalopods are sensitive to short-term perturbations, such as seasonal environmental changes, because they lack this buffering effect but they are in turn not influenced by continuous, long-term moderate disturbances such as fishing because of its high population growth and turnover. The contrary would apply to elasmobranchs, whose multi-aged population structure would buffer the seasonal environmental effects, but they would display strong responses to uninterrupted harvesting due to its low population resilience. Besides

  17. Profiling crop pollinators: life history traits predict habitat use and crop visitation by Mediterranean wild bees.

    PubMed

    Pisanty, Gideon; Mandelik, Yael

    2015-04-01

    Wild pollinators, bees in particular, may greatly contribute to crop pollination and provide a safety net against declines in commercial pollinators. However, the identity, life history traits, and environmental sensitivities of main crop pollinator species.have received limited attention. These are crucial for predicting pollination services of different communities and for developing management practices that enhance crop pollinators. We sampled wild bees in three crop systems (almond, confection sunflower, and seed watermelon) in a mosaic Israeli Mediterranean landscape. Bees were sampled in field/orchard edges and interiors, and in seminatural scrub surrounding the fields/orchards. We also analyzed land cover at 50-2500 m radii around fields/orchards. We used this data to distinguish crop from non-crop pollinators based on a set of life history traits (nesting, lecty, sociality, body size) linked to habitat preference and crop visitation. Bee abundance and species richness decreased from the surrounding seminatural habitat to the field/orchard interior, especially across the seminatural habitat-field edge ecotone. Thus, although rich bee communities were found near fields, only small fractions crossed the ecotone and visited crop flowers in substantial numbers. The bee assemblage in agricultural fields/orchards and on crop flowers was dominated by ground-nesting bees of the tribe Halictini, which tend to nest within fields. Bees' habitat preferences were determined mainly by nesting guild, whereas crop visitation was determined mainly by sociality. Lecty and body size also affected both measures. The percentage of surrounding seminatural habitat at 250-2500 m radii had a positive effect on wild bee diversity in field edges, for all bee guilds, while at 50-100 m radii, only aboveground nesters were positively affected. In sum, we found that crop and non-crop pollinators are distinguished by behavioral and morphological traits. Hence, analysis of life-history

  18. Hibernation is associated with increased survival and the evolution of slow life histories among mammals.

    PubMed

    Turbill, Christopher; Bieber, Claudia; Ruf, Thomas

    2011-11-22

    Survival probability is predicted to underlie the evolution of life histories along a slow-fast continuum. Hibernation allows a diverse range of small mammals to exhibit seasonal dormancy, which might increase survival and consequently be associated with relatively slow life histories. We used phylogenetically informed GLS models to test for an effect of hibernation on seasonal and annual survival, and on key attributes of life histories among mammals. Monthly survival was in most cases higher during hibernation compared with the active season, probably because inactivity minimizes predation. Hibernators also have approximately 15 per cent higher annual survival than similar sized non-hibernating species. As predicted, we found an effect of hibernation on the relationships between life history attributes and body mass: small hibernating mammals generally have longer maximum life spans (50% greater for a 50 g species), reproduce at slower rates, mature at older ages and have longer generation times compared with similar-sized non-hibernators. In accordance with evolutionary theories, however, hibernating species do not have longer life spans than non-hibernators with similar survival rates, nor do they have lower reproductive rates than non-hibernators with similar maximum life spans. Thus, our combined results suggest that (i) hibernation is associated with high rates of overwinter and annual survival, and (ii) an increase in survival in hibernating species is linked with the coevolution of traits indicative of relatively slow life histories.

  19. Evaluating life-history strategies of reef corals from species traits.

    PubMed

    Darling, Emily S; Alvarez-Filip, Lorenzo; Oliver, Thomas A; McClanahan, Timothy R; Côté, Isabelle M; Bellwood, David

    2012-12-01

    Classifying the biological traits of organisms can test conceptual frameworks of life-history strategies and allow for predictions of how different species may respond to environmental disturbances. We apply a trait-based classification approach to a complex and threatened group of species, scleractinian corals. Using hierarchical clustering and random forests analyses, we identify up to four life-history strategies that appear globally consistent across 143 species of reef corals: competitive, weedy, stress-tolerant and generalist taxa, which are primarily separated by colony morphology, growth rate and reproductive mode. Documented shifts towards stress-tolerant, generalist and weedy species in coral reef communities are consistent with the expected responses of these life-history strategies. Our quantitative trait-based approach to classifying life-history strategies is objective, applicable to any taxa and a powerful tool that can be used to evaluate theories of community ecology and predict the impact of environmental and anthropogenic stressors on species assemblages.

  20. Adventist Philosophy Applied to Campus Life: History of an Experience.

    ERIC Educational Resources Information Center

    Castillo, Ismael; Korniejczuk, Raquel

    2001-01-01

    Describes the general curriculum, common to all programs, at the University of Montemorelos, a Seventh-day Adventist institution, also examining the history of the curriculum design process and the implementation process. The university's institutional curriculum is congruent with the convictions and beliefs it holds regarding higher education…

  1. The uses of life: A history of biotechnology

    SciTech Connect

    Bud, R.

    1993-01-01

    This book is largely a history of what biotechnology and related terms meant many years ago. The book focuses on those aspects of biotechnology that could reasonably be considered to have arisen out of chemical engineering. Included in the book is an extensive description of a Swedish program developed by Car Heden in the 1960s to study engineering aspects of microbiology.

  2. Early life stress affects mortality rate more than social behavior, gene expression or oxidative damage in honey bee workers.

    PubMed

    Rueppell, Olav; Yousefi, Babak; Collazo, Juan; Smith, Daniel

    2017-04-01

    Early life stressors can affect aging and life expectancy in positive or negative ways. Individuals can adjust their behavior and molecular physiology based on early life experiences but relatively few studies have connected such mechanisms to demographic patterns in social organisms. Sociality buffers individuals from environmental influences and it is unclear how much early life stress affects later life history. Workers of the honey bee (Apis mellifera L.) were exposed to two stressors, Varroa parasitism and Paraquat exposure, early in life. Consequences were measured at the molecular, behavioral, and demographic level. While treatments did not significantly affect levels of oxidative damage, expression of select genes, and titers of the common deformed wing virus, most of these measures were affected by age. Some of the age effects, such as declining levels of deformed wing virus and oxidative damage, were opposite to our predictions but may be explained by demographic selection. Further analyses suggested some influences of worker behavior on mortality and indicated weak treatment effects on behavior. The latter effects were inconsistent among the two experiments. However, mortality rate was consistently reduced by Varroa mite stress during development. Thus, mortality was more responsive to early life stress than our other response variables. The lack of treatment effects on these measures may be due to the social organization of honey bees that buffers the individual from the impact of stressful developmental conditions.

  3. Does life history predict risk-taking behavior of wintering dabbling ducks?

    USGS Publications Warehouse

    Ackerman, J.T.; Eadie, J.M.; Moore, T.G.

    2006-01-01

    Life-history theory predicts that longer-lived, less fecund species should take fewer risks when exposed to predation than shorter-lived, more fecund species. We tested this prediction for seven species of dabbling ducks (Anas) by measuring the approach behavior (behavior of ducks when approaching potential landing sites) of 1099 duck flocks during 37 hunting trials and 491 flocks during 13 trials conducted immediately after the 1999-2000 waterfowl hunting season in California, USA. We also experimentally manipulated the attractiveness of the study site by using two decoy treatments: (1) traditional, stationary decoys only, and (2) traditional decoys in conjunction with a mechanical spinning-wing decoy. Approach behavior of ducks was strongly correlated with their life history. Minimum approach distance was negatively correlated with reproductive output during each decoy treatment and trial type. Similarly, the proportion of flocks taking risk (approaching landing sites to within 45 m) was positively correlated with reproductive output. We found similar patterns of approach behavior in relation to other life-history parameters (i.e., adult female body mass and annual adult female survival rate). Thus, species characterized by a slower life-history strategy (e.g., Northern Pintail [A. acuta]) were more risk-averse than species with a faster life-history strategy (e.g., Cinnamon Teal [A. cyanoptera]). Furthermore, although we were able to reduce risk-averseness using the spinning-wing decoy, we were unable to override the influence of life history on risk-taking behavior. Alternative explanations did not account for the observed correlation between approach behavior and life-history parameters. These results suggest that life history influences the risk-taking behavior of dabbling ducks and provide an explanation for the differential vulnerability of waterfowl to harvest. ?? The Cooper Ornithological Society 2006.

  4. Hormonal correlates of male life history stages in wild white-faced capuchin monkeys (Cebus capucinus)

    PubMed Central

    Jack, Katharine M.; Schoof, Valérie A.M.; Sheller, Claire R.; Rich, Catherine I.; Klingelhofer, Peter P.; Ziegler, Toni E.; Fedigan, Linda

    2014-01-01

    Much attention has been paid to hormonal variation in relation to male dominance status and reproductive seasonality, but we know relatively little about how hormones vary across life history stages. Here we examine fecal testosterone (fT), dihydrotestosterone (fDHT), and glucocorticoid (fGC) profiles across male life history stages in wild white-faced capuchins (Cebus capucinus). Study subjects included 37 males residing in three habituated social groups in the Área de Conservacíon Guanacaste, Costa Rica. Male life history stages included infant (0 to <12 months; N = 3), early juvenile (1 to <3 years; N = 10), late juvenile (3 to <6 years; N = 9), subadult (6 to <10 years; N = 8), subordinate adult (≥10 years; N = 3), and alpha adult (≥ 10 years; N = 4, including one recently deposed alpha). Life history stage was a significant predictor of fT; levels were low throughout the infant and juvenile phases, doubled in subadult and subordinate adults, and were highest for alpha males. Life history stage was not a significant predictor of fDHT, fDHT:fT, or fGC levels. Puberty in white-faced capuchins appears to begin in earnest during the subadult male phase, indicated by the first significant rise in fT. Given their high fT levels and exaggerated secondary sexual characteristics, we argue that alpha adult males represent a distinctive life history stage not experienced by all male capuchins. This study is the first to physiologically validate observable male life history stages using patterns of hormone excretion in wild Neotropical primates, with evidence for a strong association between fT levels and life history stage. PMID:24184868

  5. Species Profiles: life histories and environmental requirements of coastal fishes and invertebrates (North Atlantic)

    SciTech Connect

    Not Available

    1984-01-01

    Species Profiles are summaries of the life histories and environmental requirements of selected coastal fishes and invertebrates of commercial, recreational, or ecological significance. The Profiles will be used to relate life history and environmental requirements of species to coastal numerical water quality models and to assist in evaluating the environmental impacts of altering estuarine habitats. For this program the marine coastline of the continental United States was divided into the following seven biogeographic regions.

  6. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest). Lingcod

    DTIC Science & Technology

    1989-12-01

    Res. Board Can. Kabata, F. 1973. The species of 20(2):257-264. Lepeophiheirus ( Copepoda : Caligidae) from fishes in British Columbia. J. Fish. Res...AD-A224 839 Biological Report 82(11.119) TR EL-82-4 December 1989 OTC FiLE COPY Species Profiles: Life Histories and Environmental Requirements of...1989 Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest) LINGCOD by William N

  7. Hormonal correlates of male life history stages in wild white-faced capuchin monkeys (Cebus capucinus).

    PubMed

    Jack, Katharine M; Schoof, Valérie A M; Sheller, Claire R; Rich, Catherine I; Klingelhofer, Peter P; Ziegler, Toni E; Fedigan, Linda

    2014-01-01

    Much attention has been paid to hormonal variation in relation to male dominance status and reproductive seasonality, but we know relatively little about how hormones vary across life history stages. Here we examine fecal testosterone (fT), dihydrotestosterone (fDHT), and glucocorticoid (fGC) profiles across male life history stages in wild white-faced capuchins (Cebus capucinus). Study subjects included 37 males residing in three habituated social groups in the Área de Conservacíon Guanacaste, Costa Rica. Male life history stages included infant (0 to <12months; N=3), early juvenile (1 to <3years; N=10), late juvenile (3 to <6years; N=9), subadult (6 to <10years; N=8), subordinate adult (⩾10years; N=3), and alpha adult (⩾10years; N=4, including one recently deposed alpha). Life history stage was a significant predictor of fT; levels were low throughout the infant and juvenile phases, doubled in subadult and subordinate adults, and were highest for alpha males. Life history stage was not a significant predictor of fDHT, fDHT:fT, or fGC levels. Puberty in white-faced capuchins appears to begin in earnest during the subadult male phase, indicated by the first significant rise in fT. Given their high fT levels and exaggerated secondary sexual characteristics, we argue that alpha adult males represent a distinctive life history stage not experienced by all male capuchins. This study is the first to physiologically validate observable male life history stages using patterns of hormone excretion in wild Neotropical primates, with evidence for a strong association between fT levels and life history stage.

  8. Physical maturation, life-history classes and age estimates of free-ranging western gorillas--insights from Mbeli Bai, Republic of Congo.

    PubMed

    Breuer, Thomas; Hockemba, Mireille Breuer-Ndoundou; Olejniczak, Claudia; Parnell, Richard J; Stokes, Emma J

    2009-02-01

    Physical maturation and life-history parameters are seen as evolutionary adaptations to different ecological and social conditions. Comparison of life-history patterns of closely related species living in diverse environments helps to evaluate the validity of these assumptions but empirical data are lacking. The two gorilla species exhibit substantial differences in their environment, which allows investigation into the role of increased frugivory in shaping western gorilla life histories. We present behavioral and morphological data on western gorilla physical maturation and life-history parameters from a 12.5-year study at Mbeli Bai, a forest clearing in the Nouabalé-Ndoki National Park in northern Congo. We assign photographs of known individuals to different life-history classes and propose new age boundaries for life-history classes in western gorillas, which can be used and tested at other western gorilla research sites. Our results show that western gorillas are weaned at a later age compared with mountain gorillas and indicate slower physical maturation of immatures. These findings support the risk-aversion hypothesis for more frugivorous species. However, our methods need to be applied and tested with other gorilla populations. The slow life histories of western gorillas could have major consequences for social structure, mortality patterns and population growth rates that will affect recovery from population crashes of this critically endangered species. We emphasize that long-term studies can provide crucial demographic and life-history data that improve our understanding of life-history evolution and adaptation and help to refine conservation strategies.

  9. Ancestry trumps experience: Transgenerational but not early life stress affects the adult physiological stress response.

    PubMed

    McCormick, Gail L; Robbins, Travis R; Cavigelli, Sonia A; Langkilde, Tracy

    2017-01-01

    Exposure to stressors can affect an organism's physiology and behavior as well as that of its descendants (e.g. through maternal effects, epigenetics, and/or selection). We examined the relative influence of early life vs. transgenerational stress exposure on adult stress physiology in a species that has populations with and without ancestral exposure to an invasive predator. We raised offspring of eastern fence lizards (Sceloporus undulatus) from sites historically invaded (high stress) or uninvaded (low stress) by predatory fire ants (Solenopsis invicta) and determined how this different transgenerational exposure to stress interacted with the effects of early life stress exposure to influence the physiological stress response in adulthood. Offspring from these high- and low-stress populations were exposed weekly to either sub-lethal attack by fire ants (an ecologically relevant stressor), topical treatment with a physiologically-appropriate dose of the stress-relevant hormone, corticosterone (CORT), or a control treatment from 2 to 43weeks of age. Several months after treatments ended, we quantified plasma CORT concentrations at baseline and following restraint, exposure to fire ants, and adrenocorticotropic hormone (ACTH) injection. Exposure to fire ants or CORT during early life did not affect lizard stress physiology in adulthood. However, offspring of lizards from populations that had experienced multiple generations of fire ant-invasion exhibited more robust adult CORT responses to restraint and ACTH-injection compared to offspring from uninvaded populations. Together, these results indicate that transgenerational stress history may be at least as important, if not more important, than early life stress in affecting adult physiological stress responses.

  10. Rapid Life-History Diversification of an Introduced Fish Species across a Localized Thermal Gradient

    PubMed Central

    Zhu, Fengyue; Rypel, Andrew L.; Murphy, Brian R.; Li, Zhongjie; Zhang, Tanglin; Yuan, Jing; Guo, Zhiqiang; Tang, Jianfeng; Liu, Jiashou

    2014-01-01

    Climatic variations are known to engender life-history diversification of species and populations at large spatial scales. However, the extent to which microgeographic variations in climate (e.g., those occurring within a single large ecosystem) can also drive life-history divergence is generally poorly documented. We exploited a spatial gradient in water temperatures at three sites across a large montane lake in southwest China (Lake Erhai) to examine the extent to which life histories of a short-lived fish species (icefish, Neosalanx taihuensis) diversified in response to thermal regime following introduction 25 y prior. In general, warmwater icefish variants grew faster, had larger adult body size and higher condition and fecundity, but matured at smaller sizes. Conversely, coldwater variants had smaller adult body size and lower condition, but matured at larger sizes and had larger eggs. These life-history differences strongly suggest that key ecological trade-offs exist for icefish populations exposed to different thermal regimes, and these trade-offs have driven relatively rapid diversification in the life histories of icefish within Lake Erhai. Results are surprisingly concordant with current knowledge on life-history evolution at macroecological scales, and suggest that improved conservation management might be possible by focusing on patterns operating at microgeographical, including, within-ecosystem scales. PMID:24505366

  11. Life history variation in a marine teleost across a heterogeneous seascape

    NASA Astrophysics Data System (ADS)

    Sala-Bozano, Maria; Mariani, Stefano

    2011-05-01

    Life history traits, primarily related to growth and reproduction, often reflect the process of adaptation of organisms to their natural environment. Consequently, life history parameters are expected to differ along heterogeneous habitats. Provided the pivotal role of life-history traits in determining fitness, the description and understanding of life history variation is a central goal in evolutionary ecology. In order to test the influence of the known environmental heterogeneity of Mediterranean coastal seas, populations of the striped sea bream Lithognathus mormyrus, were sampled from five distinct geographic areas within, or adjacent to, the Mediterranean basin (Aborán Sea, Balearic Sea, Tyrrhenian Sea, Adriatic Sea and the Gulf of Cadiz in the Atlantic Ocean). Growth patterns, maturation, sex-ratio, sex change and feeding habits were investigated over two years and revealed large-scale life history variation. Similarly slanted growth, earlier maturation times and smaller size-at-sex change were found in the Tyrrhenian and the Adriatic populations, which appear in contrast with recent population genetic investigation. The potential influence of fishery exploitation on these traits is discussed as a possible determining factor. The present study provides an exemplar of life-history variation across a heterogeneous seascape and makes a case for a more judicious consideration of ecological information for the purpose of identifying population units for management and conservation.

  12. Copepod reproductive strategies: life-history theory, phylogenetic pattern and invasion of inland waters

    NASA Astrophysics Data System (ADS)

    Hairston, Nelson G.; Bohonak, Andrew J.

    1998-06-01

    Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven by tradeoffs that are mediated by the environment in which the organisms live. At the same time, phylogenetic history may circumscribe natural selection by dictating the range of phenotypes upon which selection can act, or by limiting the range of environments encountered. Comparisons of life-history patterns in related organisms provide a powerful tool for understanding both the nature of selection on life-history characters and the diversity of life-history patterns observed in nature. Here, we explore reproductive strategies of the Copepoda, a well defined group with many phylogenetically independent transitions from free-living to parasitic life styles, from marine to inland waters, and from active development to diapause. Most species are iteroparous annuals, and most (with the exception of some parasitic taxa) develop through a relatively restricted range of life-history stages (nauplii and copepodids, or some modification thereof). Within these bounds, we suggest that there may be a causal relationship between the success of numerous copepod taxa in inland waters and the prevalence of either diapause or parasitism within these groups. We hypothesize that inland waters are more variable spatially and temporally than marine habitats, and accordingly, we interpret diapause and parasitism as mechanisms for coping with environmental variance.

  13. The genomic and physiological basis of life history variation in a butterfly metapopulation.

    PubMed

    Klepsatel, Peter; Flatt, Thomas

    2011-05-01

    Unravelling the mechanisms underlying variation in life history traits is of fundamental importance for our understanding of adaptation by natural selection. While progress has been made in mapping fitness-related phenotypes to genotypes, mainly in a handful of model organisms, functional genomic studies of life history adaptations are still in their infancy. In particular, despite a few notable exceptions, the genomic basis of life history variation in natural populations remains poorly understood. This is especially true for the genetic underpinnings of life history phenotypes subject to diversifying selection driven by ecological dynamics in patchy environments--as opposed to adaptations involving strong directional selection owing to major environmental changes, such as latitudinal gradients, extreme climatic events or transitions from salt to freshwater. In this issue of Molecular Ecology,Wheat et al. (2011) now make a significant leap forward by applying the tools of functional genomics to dispersal-related life history variation in a butterfly metapopulation. Using a combination of microarrays, quantitative PCR and physiological measurements, the authors uncover several metabolic and endocrine factors that likely contribute to the observed life history phenotypes. By identifying molecular candidate mechanisms of fitness variation maintained by dispersal dynamics in a heterogeneous environment,they also begin to address fascinating interactions between the levels of physiology, ecology and evolution.

  14. A life history study of the yellow throat

    USGS Publications Warehouse

    Stewart, R.E.

    1953-01-01

    Investigations concerning the life history of the Yellow-throat were made in southern Michigan during the spring and summer of 1938. Supplementary information was also obtained at Arlington, Virginia, in 1940 and at the Patuxent Research Refuge, Maryland, in 1947.....Resident males established territories almost immediately upon arrival in spring. In southern Michigan some resident males arrived at least as soon as, if not before, transient males. Most females appeared on their nesting ground about a week later. Adults were engaged in nesting activities from the time of their arrival in spring until the advent of the post-nuptial molt in late summer.....Typical Yellow-throat habitat consists of a mixture of a dense herbaceous vegetation and small woody plants in damp or wet situations. At Ann Arbor, the Yellow-throat was a common breeding species in its restricted suitable habitat. The population density in one area of suitable habitat was about 69 territorial males per 100 acres. Of 11 territorial males that were intensively studied, one was polygamous (with two mates), nine were monogamous, and one was probably monogamous (with at least one mate).....The song of the individual Yellow-throat was heard throughout the breeding season except for the courtship period. Two major types of song were the common song given while perched, and an occasional, more elaborate, flight song. Most males sing in spurts, singing at fairly regular intervals for a considerable period and then abruptly ceasing for another period. The vocabulary of both sexes included several types of call notes that appeared either to have special functions or to represent outward expressions of distinct emotional states of the bird.....Resident males were antagonistic toward each other throughout the breeding season. Most remained on well-established territories during this period. Territories of 10 monogamous males ranged in size from .8 to 1.8 acres but the territory of one polygamous male occupied

  15. Life history and dynamics of a platypus (Ornithorhynchus anatinus) population: four decades of mark-recapture surveys.

    PubMed

    Bino, Gilad; Grant, Tom R; Kingsford, Richard T

    2015-11-05

    Knowledge of the life-history and population dynamics of Australia's iconic and evolutionarily distinct platypus (Ornithorhynchus anatinus) remains poor. We marked-recaptured 812 unique platypuses (total 1,622 captures), over four decades (1973-2014) in the Shoalhaven River, Australia. Strong sex-age differences were observed in life-history, including morphology and longevity. Apparent survival of adult females (Φ = 0.76) were higher than adult males (Φ = 0.57), as in juveniles: females Φ = 0.27, males Φ = 0.13. Females were highly likely to remain in the same pool (adult: P = 0.85, juvenile: P = 0.88), while residency rates were lower for males (adult: P = 0.74, juvenile: P = 0.46). We combined survival, movement and life-histories to develop population viability models and test the impact of a range of life-history parameters. While using estimated apparent survival produced unviable populations (mean population growth rate r = -0.23, extinction within 20 years), considering residency rates to adjust survival estimates, indicated more stable populations (r = 0.004, p = 0.04 of 100-year extinction). Further sensitivity analyses highlighted adult female survival and overall success of dispersal as most affecting viability. Findings provide robust life-history and viability estimates for a difficult study species. These could support developing large-scale population dynamics models required to underpin a much needed national risk assessment for the platypus, already declining in parts of its current distribution.

  16. Life History Traits and Niche Instability Impact Accuracy and Temporal Transferability for Historically Calibrated Distribution Models of North American Birds

    PubMed Central

    Wogan, Guinevere O. U.

    2016-01-01

    A primary assumption of environmental niche models (ENMs) is that models are both accurate and transferable across geography or time; however, recent work has shown that models may be accurate but not highly transferable. While some of this is due to modeling technique, individual species ecologies may also underlie this phenomenon. Life history traits certainly influence the accuracy of predictive ENMs, but their impact on model transferability is less understood. This study investigated how life history traits influence the predictive accuracy and transferability of ENMs using historically calibrated models for birds. In this study I used historical occurrence and climate data (1950-1990s) to build models for a sample of birds, and then projected them forward to the ‘future’ (1960-1990s). The models were then validated against models generated from occurrence data at that ‘future’ time. Internal and external validation metrics, as well as metrics assessing transferability, and Generalized Linear Models were used to identify life history traits that were significant predictors of accuracy and transferability. This study found that the predictive ability of ENMs differs with regard to life history characteristics such as range, migration, and habitat, and that the rarity versus commonness of a species affects the predicted stability and overlap and hence the transferability of projected models. Projected ENMs with both high accuracy and transferability scores, still sometimes suffered from over- or under- predicted species ranges. Life history traits certainly influenced the accuracy of predictive ENMs for birds, but while aspects of geographic range impact model transferability, the mechanisms underlying this are less understood. PMID:26959979

  17. Life history and dynamics of a platypus (Ornithorhynchus anatinus) population: four decades of mark-recapture surveys

    PubMed Central

    Bino, Gilad; Grant, Tom R.; Kingsford, Richard T.

    2015-01-01

    Knowledge of the life-history and population dynamics of Australia’s iconic and evolutionarily distinct platypus (Ornithorhynchus anatinus) remains poor. We marked-recaptured 812 unique platypuses (total 1,622 captures), over four decades (1973–2014) in the Shoalhaven River, Australia. Strong sex-age differences were observed in life-history, including morphology and longevity. Apparent survival of adult females (Φ = 0.76) were higher than adult males (Φ = 0.57), as in juveniles: females Φ = 0.27, males Φ = 0.13. Females were highly likely to remain in the same pool (adult: P = 0.85, juvenile: P = 0.88), while residency rates were lower for males (adult: P = 0.74, juvenile: P = 0.46). We combined survival, movement and life-histories to develop population viability models and test the impact of a range of life-history parameters. While using estimated apparent survival produced unviable populations (mean population growth rate r = −0.23, extinction within 20 years), considering residency rates to adjust survival estimates, indicated more stable populations (r = 0.004, p = 0.04 of 100-year extinction). Further sensitivity analyses highlighted adult female survival and overall success of dispersal as most affecting viability. Findings provide robust life-history and viability estimates for a difficult study species. These could support developing large-scale population dynamics models required to underpin a much needed national risk assessment for the platypus, already declining in parts of its current distribution. PMID:26536832

  18. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (South Atlantic): Spot

    SciTech Connect

    Hales, L.S.; Van Den Avyle, M.J.

    1989-01-01

    Species profiles are literature summaries of the life history, distribution, and environmental requirements of coastal fishes and invertebrates. Profiles are prepared to assist with environmental impact assessment. The spot (Leiostomus xanthurus) is an abundant fish is coastal waters of the South Atlantic Region. It is important to commercial and recreational fisheries. In the South Atlantic Region, spot spawn commercial from October to March. The larvae are transported from the offshore spawning grounds to estuarine nursery areas. Juvenile spot initially congregate in shallow tidal creeks, but then disperse into deeper water as they get larger. Spot mature at 2-3 years of age. As larvae, spot feed on plankton, but switch to benthic invertebrates as juveniles and adults. Juvenile and adult spot are eaten by many other fishes. Tolerance to thermal shock and other environmental extremes varies with developmental stage. Alterations of the salinity or temperature regimes of an estuary may affect populations of spot; disturbances that affect the benthic community upon which spot feed may also affect spot abundance. Spot are not strong swimmers and may, therefore, suffer significant mortality due to intake structures at industrial or power generation plants. 127 refs., 2 figs.

  19. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (South Atlantic). Biological report

    SciTech Connect

    Hales, L.S.; Avyle, M.J.V.D.

    1989-01-01

    Species profiles are literature summaries of the life history, distribution, and environmental requirements of coastal fishes and invertebrates. Profiles are prepared to assist with environmental-impact assessment. The spot (Leiostomus xanthurus) is an abundant fish in coastal waters of the South Atlantic Region. It is important to commercial and recreational fisheries. In the South Atlantic Region, spot spawn offshore from October to March. The larvae are transported from the offshore spawning grounds to estuarine nursery areas. Juvenile spot initially congregate in shallow tidal creeks, but then disperse into deeper water as they get larger. Spot mature at 2-3 years of age. As larvae, spot feed on plankton, but switch to benthic invertebrates as juveniles and adults. Juvenile and adult spot are eaten by many other fishes. Tolerance to thermal shock and other environmental extremes varies with developmental stage. Alterations of the salinity or temperature regimes of an estuary may affect populations of spot; disturbances that affect the benthic community upon which spot feed may also affect spot abundance. Spot are not strong swimmers and may, therefore, suffer significant mortality due to intake structures at industrial or power generation plants.

  20. [Life history interview--an effective approach to building positive doctor-patient relations and guide to proper end of life home care].

    PubMed

    Yamanashi, Hirotomo; Yamanashi, Irotomo; Miyamori, Tadashi

    2010-12-01

    The acclaimed psychiatrist, Arthur Kleinman, proposed Life History Interview as a way of enabling doctors to truly listen to a patient who is suffering from chronic disease. Two cases of terminally ill patients were carried out with Life History Interview. When speaking of the end of life home care, Life History Interview is an effective approach in building positive doctor-patient relations in the early stages. It truly allows for a good foundation for providing a proper care.

  1. Women in History--Abigail Adams: Life, Accomplishments, and Ideas

    ERIC Educational Resources Information Center

    Kenan, Sharon K.

    2008-01-01

    This article profiles the life, accomplishments, and ideas of Abigail Adams. Born in 1944, Adams lacked a formal education, but she more than made up for that shortcoming with her love of reading, especially literature, and her interests in politics and events surrounding the young colonies. Adams was supportive of the advancement of women. She…

  2. An unexpected life in optical science: a personal history

    NASA Astrophysics Data System (ADS)

    Bohren, Craig F.

    2010-02-01

    "The race is not to the swift, nor the battle to the strong, neither yet bread to the wise nor yet riches to men of understanding, nor yet favor to men of skill; but time and chance happeneth to them all." This in a nutshell describes the life and scientific career of Craig Bohren.

  3. The History of Black Star Picture Agency: "Life's" European Connection.

    ERIC Educational Resources Information Center

    Smith, C. Zoe

    Historians of photography have failed to explore the origins of the Black Star Picture Agency and how it introduced experienced photojournalists to Henry Luce, a publisher attempting to break new ground in American journalism with the introduction of a picture magazine, "Life," in 1936. Black Star's founders, Ernest Mayer, Kurt Kornfeld,…

  4. Effects of life-history traits on parasitism in a monogamous mammal, the eastern rock sengi ( Elephantulus myurus)

    NASA Astrophysics Data System (ADS)

    Lutermann, Heike; Medger, Katarina; Horak, Ivan G.

    2012-02-01

    The distribution of parasites is often characterised by substantial aggregation with a small proportion of hosts harbouring the majority of parasites. This pattern can be generated by abiotic and biotic factors that affect hosts and determine host exposure and susceptibility to parasites. Climate factors can change a host's investment in life-history traits (e.g. growth, reproduction) generating temporal patterns of parasite aggregation. Similarly, host age may affect such investment. Furthermore, sex-biased parasitism is common among vertebrates and has been linked to sexual dimorphism in morphology, behaviour and physiology. Studies exploring sex-biased parasitism have been almost exclusively conducted on polygynous species where dimorphic traits are often correlated. We investigated the effects of season and life-history traits on tick loads of the monogamous eastern rock sengi ( Elephantulus myurus). We found larger tick burdens during the non-breeding season possibly as a result of energetic constraints and/or climate effects on the tick. Reproductive investment resulted in increased larval abundance for females but not males and may be linked to sex-specific life-history strategies. The costs of reproduction could also explain the observed age effect with yearling individuals harbouring lower larval burdens than adults. Although adult males had the greatest larval tick loads, host sex appears to play a minor role in generating the observed parasite heterogeneities. Our study suggests that reproductive investment plays a major role for parasite patterns in the study species.

  5. Environmental drivers defining linkages among life-history traits: mechanistic insights from a semiterrestrial amphipod subjected to macroscale gradients

    PubMed Central

    Gómez, Julio; Barboza, Francisco R; Defeo, Omar

    2013-01-01

    Determining the existence of interconnected responses among life-history traits and identifying underlying environmental drivers are recognized as key goals for understanding the basis of phenotypic variability. We studied potentially interconnected responses among senescence, fecundity, embryos size, weight of brooding females, size at maturity and sex ratio in a semiterrestrial amphipod affected by macroscale gradients in beach morphodynamics and salinity. To this end, multiple modelling processes based on generalized additive mixed models were used to deal with the spatio-temporal structure of the data obtained at 10 beaches during 22 months. Salinity was the only nexus among life-history traits, suggesting that this physiological stressor influences the energy balance of organisms. Different salinity scenarios determined shifts in the weight of brooding females and size at maturity, having consequences in the number and size of embryos which in turn affected sex determination and sex ratio at the population level. Our work highlights the importance of analysing field data to find the variables and potential mechanisms that define concerted responses among traits, therefore defining life-history strategies. PMID:24198949

  6. A review of Ruffe (Gymnocephalus cernuus) life history and implications for spread

    EPA Science Inventory

    Ruffe (Gymnocephalus cernuus) are among the most widespread fish invaders in Lake Superior. The objective of this study was to gather information on the complete life cycle of Ruffe in both their native and non-native ranges to characterize their life history strategies. A study ...

  7. Effect of Temperature on the life history of the mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effect of temperature on the life history of the mealybug, Paracoccus marginatus Williams and Granara de Willink was investigated in the laboratory. Paracoccus marginatus was able to develop and complete its life cycle at 18, 20, 25, and 30 ± 1°C. At 15, 34, and 35°C, the eggs hatched after 27, 6,...

  8. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Florida). SNOOK,

    DTIC Science & Technology

    FISHES, *MARINE BIOLOGY , ADULTS, RECREATION, SEASONS, COMMERCIAL FISHING, ECOLOGY , ENVIRONMENTS, REQUIREMENTS, PRESSURE, BRACKISH WATER, INSHORE...AREAS, STREAMS, TIDES, COASTAL REGIONS, DEGRADATION, HABITATS, ENVIRONMENTAL IMPACT, ESTUARIES, FRESH WATER, OCEANS, INVERTEBRATES, HISTORY, LIFE( BIOLOGY ...LIMITATIONS, LOW LEVEL, LOW TEMPERATURE, POPULATION, SALTS, SWAMPS, PROFILES, YOUTH, DOCUMENTS, WATER, FISHERIES, FLORIDA, SOUTH(DIRECTION), TAXONOMY , LIFE CYCLES, REPRODUCTION(PHYSIOLOGY)

  9. Ecological interactions in dinosaur communities: influences of small offspring and complex ontogenetic life histories.

    PubMed

    Codron, Daryl; Carbone, Chris; Clauss, Marcus

    2013-01-01

    Because egg-laying meant that even the largest dinosaurs gave birth to very small offspring, they had to pass through multiple ontogenetic life stages to adulthood. Dinosaurs' successors as the dominant terrestrial vertebrate life form, the mammals, give birth to live young, and have much larger offspring and less complex ontogenetic histories. The larger number of juveniles in dinosaur as compared to mammal ecosystems represents both a greater diversity of food available to predators, and competitors for similar-sized individuals of sympatric species. Models of population abundances across different-sized species of dinosaurs and mammals, based on simulated ecological life tables, are employed to investigate how differences in predation and competition pressure influenced dinosaur communities. Higher small- to medium-sized prey availability leads to a normal body mass-species richness (M-S) distribution of carnivorous dinosaurs (as found in the theropod fossil record), in contrast to the right-skewed M-S distribution of carnivorous mammals (as found living members of the order Carnivora). Higher levels of interspecific competition leads to a left-skewed M-S distribution in herbivorous dinosaurs (as found in sauropods and ornithopods), in contrast to the normal M-S distribution of large herbivorous mammals. Thus, our models suggest that differences in reproductive strategy, and consequently ontogeny, explain observed differences in community structure between dinosaur and mammal faunas. Models also show that the largest dinosaurian predators could have subsisted on similar-sized prey by including younger life stages of the largest herbivore species, but that large predators likely avoided prey much smaller than themselves because, despite predicted higher abundances of smaller than larger-bodied prey, contributions of small prey to biomass intake would be insufficient to satisfy meat requirements. A lack of large carnivores feeding on small prey exists in mammals

  10. Ecological Interactions in Dinosaur Communities: Influences of Small Offspring and Complex Ontogenetic Life Histories

    PubMed Central

    Codron, Daryl; Carbone, Chris; Clauss, Marcus

    2013-01-01

    Because egg-laying meant that even the largest dinosaurs gave birth to very small offspring, they had to pass through multiple ontogenetic life stages to adulthood. Dinosaurs’ successors as the dominant terrestrial vertebrate life form, the mammals, give birth to live young, and have much larger offspring and less complex ontogenetic histories. The larger number of juveniles in dinosaur as compared to mammal ecosystems represents both a greater diversity of food available to predators, and competitors for similar-sized individuals of sympatric species. Models of population abundances across different-sized species of dinosaurs and mammals, based on simulated ecological life tables, are employed to investigate how differences in predation and competition pressure influenced dinosaur communities. Higher small- to medium-sized prey availability leads to a normal body mass-species richness (M-S) distribution of carnivorous dinosaurs (as found in the theropod fossil record), in contrast to the right-skewed M-S distribution of carnivorous mammals (as found living members of the order Carnivora). Higher levels of interspecific competition leads to a left-skewed M-S distribution in herbivorous dinosaurs (as found in sauropods and ornithopods), in contrast to the normal M-S distribution of large herbivorous mammals. Thus, our models suggest that differences in reproductive strategy, and consequently ontogeny, explain observed differences in community structure between dinosaur and mammal faunas. Models also show that the largest dinosaurian predators could have subsisted on similar-sized prey by including younger life stages of the largest herbivore species, but that large predators likely avoided prey much smaller than themselves because, despite predicted higher abundances of smaller than larger-bodied prey, contributions of small prey to biomass intake would be insufficient to satisfy meat requirements. A lack of large carnivores feeding on small prey exists in mammals

  11. Convergent and correlated evolution of major life-history traits in the angiosperm genus Leucadendron (Proteaceae).

    PubMed

    Tonnabel, Jeanne; Mignot, Agnès; Douzery, Emmanuel J P; Rebelo, Anthony G; Schurr, Frank M; Midgley, Jeremy; Illing, Nicola; Justy, Fabienne; Orcel, Denis; Olivieri, Isabelle

    2014-10-01

    Natural selection is expected to cause convergence of life histories among taxa as well as correlated evolution of different life-history traits. Here, we quantify the extent of convergence of five key life-history traits (adult fire survival, seed storage, degree of sexual dimorphism, pollination mode, and seed-dispersal mode) and test hypotheses about their correlated evolution in the genus Leucadendron (Proteaceae) from the fire-prone South African fynbos. We reconstructed a new molecular phylogeny of this highly diverse genus that involves more taxa and molecular markers than previously. This reconstruction identifies new clades that were not detected by previous molecular study and morphological classifications. Using this new phylogeny and robust methods that account for phylogenetic uncertainty, we show that the five life-history traits studied were labile during the evolutionary history of the genus. This diversity allowed us to tackle major questions about the correlated evolution of life-history strategies. We found that species with longer seed-dispersal distances tended to evolve lower pollen-dispersal distance, that insect-pollinated species evolved decreased sexual dimorphism, and that species with a persistent soil seed-bank evolved toward reduced fire-survival ability of adults.

  12. Timing of seasonal migration in mule deer: effects of climate, plant phenology, and life-history characteristics

    USGS Publications Warehouse

    Monteith, Kevin L.; Bleich, Vernon C.; Stephenson, Thomas R.; Pierce, Beck M.; Conner, Mary M.; Klaver, Robert W.; Bowyer, R. Terry

    2011-01-01

    Phenological events of plants and animals are sensitive to climatic processes. Migration is a life-history event exhibited by most large herbivores living in seasonal environments, and is thought to occur in response to dynamics of forage and weather. Decisions regarding when to migrate, however, may be affected by differences in life-history characteristics of individuals. Long-term and intensive study of a population of mule deer (Odocoileus hemionus) in the Sierra Nevada, California, USA, allowed us to document patterns of migration during 11 years that encompassed a wide array of environmental conditions. We used two new techniques to properly account for interval-censored data and disentangle effects of broad-scale climate, local weather patterns, and plant phenology on seasonal patterns of migration, while incorporating effects of individual life-history characteristics. Timing of autumn migration varied substantially among individual deer, but was associated with the severity of winter weather, and in particular, snow depth and cold temperatures. Migratory responses to winter weather, however, were affected by age, nutritional condition, and summer residency of individual females. Old females and those in good nutritional condition risked encountering severe weather by delaying autumn migration, and were thus risk-prone with respect to the potential loss of foraging opportunities in deep snow compared with young females and those in poor nutritional condition. Females that summered on the west side of the crest of the Sierra Nevada delayed autumn migration relative to east-side females, which supports the influence of the local environment on timing of migration. In contrast, timing of spring migration was unrelated to individual life-history characteristics, was nearly twice as synchronous as autumn migration, differed among years, was related to the southern oscillation index, and was influenced by absolute snow depth and advancing phenology of plants

  13. Life history and life tables of Bactericera cockerelli (Homoptera: Psyllidae) on eggplant and bell pepper.

    PubMed

    Yang, Xiang-Bing; Liu, Tong-Xian

    2009-12-01

    The development, survivorship, and fecundity of the potato psyllid, Bactericera cockerelli (Sulc), fed on eggplant (Solanum melongena L., variety Special Hibush) and bell pepper (Capsicum annuum L., variety Capsitrano) were studied in the laboratory at 26.7 +/- 2 degrees C, 70 +/- 5% RH, and at a photoperiod of 14:10 (L:D) h. Immature B. cockerelli developed faster (24.1 d) when fed on eggplant than on bell pepper (26.2 d). Survival rates of immature stages from egg to adult emergence were higher on eggplant (50.2%) than on bell pepper (34.6%). The longevity of B. cockerelli female adults fed on bell pepper was similar to that of females fed on eggplant (62.2 versus 55.0 d), but the male adults fed on eggplant lived shorter lives (39.4 d) than those fed on bell pepper (53.9 d). However, the preoviposition and oviposition periods, fecundity, and sex ratio of B. cockerelli fed on eggplant were not different from those fed on bell pepper. The r(m ) value and the finite rate of increase (lambda) of B. cockerelli were higher on eggplant (0.1099 and 1.116, respectively) than on bell pepper (0.0884 and 1.0924, respectively). Mean generation time and doubling time of B. cockerelli were shorter on eggplant (40.4 and 6.3 d, respectively) than on bell pepper (46.1 and 7.8 d, respectively). In contrast, lifetime fecundity of B. cockerelli was greater on bell pepper (227.3 offspring) than on eggplant (186.5 offspring). Based on these life history parameters, we concluded that B. cockerelli performed better on eggplant than on bell pepper.

  14. A History of Spacecraft Environmental Control and Life Support Systems

    NASA Technical Reports Server (NTRS)

    Daues, Katherine R.

    2006-01-01

    A spacecraft's Environmental Control and Life Support (ECLS) system enables and maintains a habitable and sustaining environment for its crew. A typical ECLS system provides for atmosphere consumables and revitalization, environmental monitoring, pressure, temperature and humidity control, heat rejection (including equipment cooling), food and water supply and management, waste management, and fire detection and suppression. The following is a summary of ECLS systems used in United States (US) and Russian human spacecraft.

  15. Cross-cultural Comparison of Learning in Human Hunting : Implications for Life History Evolution.

    PubMed

    MacDonald, Katharine

    2007-12-01

    This paper is a cross-cultural examination of the development of hunting skills and the implications for the debate on the role of learning in the evolution of human life history patterns. While life history theory has proven to be a powerful tool for understanding the evolution of the human life course, other schools, such as cultural transmission and social learning theory, also provide theoretical insights. These disparate theories are reviewed, and alternative and exclusive predictions are identified. This study of cross-cultural regularities in how children learn hunting skills, based on the ethnographic literature on traditional hunters, complements existing empirical work and highlights future areas for investigation.

  16. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest): Pismo clam

    SciTech Connect

    Shaw, W.N.; Hassler, T.J.

    1989-02-01

    Species profile are literature summaries of the taxonomy, morphology, distribution, life history, and environmental requirements of coastal aquatic species. They are prepared to assist in environmental impact assessment. The Pismo clam (Tivela stultorum) supports an important sport fishery in the Pacific Southwest region, but has no present commercial importance. This review describes the life history (spawning, eggs, and larval stages, postlarvae and juveniles, maturity, and life-span), growth characteristics, former commercial and sport fisheries, ecological role, and environmental requirements. 30 refs., 4 figs., 3 tabs.

  17. Repeated Lake-Stream Divergence in Stickleback Life History within a Central European Lake Basin

    PubMed Central

    Moser, Dario; Roesti, Marius; Berner, Daniel

    2012-01-01

    Life history divergence between populations inhabiting ecologically distinct habitats might be a potent source of reproductive isolation, but has received little attention in the context of speciation. We here test for life history divergence between threespine stickleback inhabiting Lake Constance (Central Europe) and multiple tributary streams. Otolith analysis shows that lake fish generally reproduce at two years of age, while their conspecifics in all streams have shifted to a primarily annual life cycle. This divergence is paralleled by a striking and consistent reduction in body size and fecundity in stream fish relative to lake fish. Stomach content analysis suggests that life history divergence might reflect a genetic or plastic response to pelagic versus benthic foraging modes in the lake and the streams. Microsatellite and mitochondrial markers further reveal that life history shifts in the different streams have occurred independently following the colonization by Lake Constance stickleback, and indicate the presence of strong barriers to gene flow across at least some of the lake-stream habitat transitions. Given that body size is known to strongly influence stickleback mating behavior, these barriers might well be related to life history divergence. PMID:23226528

  18. Allometric scaling of production and life-history variation in vascular plants

    NASA Astrophysics Data System (ADS)

    Enquist, Brian J.; West, Geoffrey B.; Charnov, Eric L.; Brown, James H.

    1999-10-01

    A prominent feature of comparative life histories is the well documented negative correlation between growth rate and life span. Patterns of resource allocation during growth and reproduction reflect life-history differences between species. This is particularly striking in tropical forests, where tree species can differ greatly in their rates of growth and ages of maturity but still attain similar canopy sizes. Here we provide a theoretical framework for relating life-history variables to rates of production, dM/dt, where M is above-ground mass and t is time. As metabolic rate limits production as an individual grows, dM/dt ~ M3/4. Incorporating interspecific variation in resource allocation to wood density, we derive a universal growth law that quantitatively fits data for a large sample of tropical tree species with diverse life histories. Combined with evolutionary life-history theory, the growth law also predicts several qualitative features of tree demography and reproduction. This framework also provides a general quantitative answer to why relative growth rate (1/M)(dM/df) decreases with increasing plant size (~M-1/4) and how it varies with differing allocation strategies.

  19. Modelling the Geographical Range of a Species with Variable Life-History

    PubMed Central

    Macfadyen, Sarina; Kriticos, Darren J.

    2012-01-01

    We show how a climatic niche model can be used to describe the potential geographic distribution of a pest species with variable life-history, and illustrate how to estimate biogeographic pest threats that vary across space. The models were used to explore factors that affect pest risk (irrigation and presences of host plant). A combination of current distribution records and published experimental data were used to construct separate models for the asexual and sexual lineages of Rhopalosiphum padi (Linnaeus) (Hemiptera: Aphididae). The two models were combined with knowledge of host plant presence to classify the global pest risk posed by R. padi. Whilst R. padi has a relatively limited area in which sexual lineages can persist year round, a much larger area is suitable for transient sexual and asexual lineages to exist. The greatest risk of establishment of persistent sexual and asexual populations is in areas with warm temperate climates. At the global scale the models show very little difference in risk patterns between natural rainfall and irrigation scenarios, but in Australia, the amount of land suitable for persistent asexual and transient sexual populations decreases (by 20%) if drought stress is no longer alleviated by irrigation. This approach proved useful for modelling the potential distribution of a species that has a variable life-history. We were able to use the model outputs to examine factors such as irrigation practices and host plant presence that altered the nature (transient or permanent) and extent of pest risk. The composite niche maps indicate pest risk in terms that are useful to both biosecurity agencies and pest managers. PMID:22808133

  20. Linking habitat structure to life history strategy: Insights from a Mediterranean killifish

    NASA Astrophysics Data System (ADS)

    Cavraro, Francesco; Daouti, Irini; Leonardos, Ioannis; Torricelli, Patrizia; Malavasi, Stefano

    2014-01-01

    Modern theories of life history evolution deal with finding links between environmental factors, demographic structure of animal populations and the optimal life history strategy. Small-sized teleost fish, occurring in fragmented populations under contrasting environments, have been widely used as study models to investigate these issues. In the present study, the Mediterranean killifish Aphanius fasciatus was used to investigate the relationships between some habitat features and life history strategy. We selected four sites in the Venice lagoon inhabited by this species, exhibiting different combinations of two factors: overall adult mortality, related to intertidal water coverage and a consequent higher level of predator exposure, and the level of sediment organic matter, as indicator of habitat trophic richness. Results showed that these were the two most important factors influencing demography and life history traits in the four sites. Fish from salt marshes with high predator pressure were smaller and produced a higher number of eggs, whereas bigger fish and a lower reproductive investment were found in the two closed, not tidally influenced habitats. Habitat richness was positively related with population density, but negatively related with growth rate. In particular the synergy between high resources and low predation level was found to be important in shaping peculiar life history traits. Results were discussed in the light of the interactions between selective demographic forces acting differentially on age/size classes, such as predation, and habitat trophic richness that may represent an important energetic constraint on life history traits. The importance to link habitat productivity and morphology to demographic factors for a better understanding of the evolution of life history strategy under contrasting environments was finally suggested.

  1. Maturation characteristics and life history strategies of the Pacific Lamprey, Entosphenus tridentatus

    USGS Publications Warehouse

    Clemens, Benjamin J.; van de Wetering, Stan; Sower, Stacia A.; Schreck, Carl B.

    2013-01-01

    Lampreys (Petromyzontiformes) have persisted over millennia and now suffer a recent decline in abundance. Complex life histories may have factored in their persistence; anthropogenic perturbations in their demise. The complexity of life histories of lampreys is not understood, particularly for the anadromous Pacific lamprey, Entosphenus tridentatus Gairdner, 1836. Our goals were to describe the maturation timing and associated characteristics of adult Pacific lamprey, and to test the null hypothesis that different life histories do not exist. Females exhibited early vitellogenesis – early maturation stages; males exhibited spermatogonia – spermatozoa. Cluster analyses revealed an “immature” group and a “maturing–mature” group for each sex. We found statistically significant differences between these groups in the relationships between (i) body mass and total length in males; (ii) Fulton’s condition factor and liver lipids in males; (iii) the gonadosomatic index (GSI) and liver lipids in females; (iv) GSI and total length in females; (v) mean oocyte diameter and liver lipids; and (vi) mean oocyte diameter and GSI. We found no significant difference between the groups in the relationship of muscle lipids and body mass. Our analyses support rejection of the hypothesis of a single life history. We found evidence for an “ocean-maturing” life history that would likely spawn within several weeks of entering fresh water, in addition to the formerly recognized life history of spending 1 year in fresh water prior to spawning—the “stream-maturing” life history. Late maturity, semelparity, and high fecundity suggest that Pacific lamprey capitalize on infrequent opportunities for reproduction in highly variable environments.

  2. Eggshell Types and Their Evolutionary Correlation with Life-History Strategies in Squamates

    PubMed Central

    Hallmann, Konstantin; Griebeler, Eva Maria

    2015-01-01

    The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (hereafter “shell-less”). Recent studies showed that life-history strategies of gekkotan species differ between species with parchment- and rigid-shelled eggshells. Here we test if the three different eggshell types found in the squamates are also associated with different life-history strategies. We first investigated the influence of the phylogeny on the trait “eggshell type” and on six life-history traits of 32 squamate species. Phylogenetic principal component analysis (pPCA) was then conducted to identify an association between life-history strategies and eggshell types. Finally, we also considered adult weight in the pPCA to examine its potential effect on this association. Eggshell types in squamates show a strong phylogenetic signal at a low taxonomical level. Four out of the six life-history traits showed also a phylogenetic signal (birth size, clutch size, clutches per year and age at female maturity), while two had none (incubation time, maximum longevity). The pPCA suggested an association of life-history strategies and eggshell types, which disappeared when adult weight was included in the analysis. We conclude that the variability seen in eggshell types of squamates is weakly influenced by phylogeny. Eggshell types correlate with different life-history strategies, and mainly reflect differences in adult weights of species. PMID:26393343

  3. Growth and life history variability of the grey reef shark (Carcharhinus amblyrhynchos) across its range

    PubMed Central

    Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P.; McCauley, Douglas J.; Pollock, Kydd; Kendall, Bruce E.; Gaines, Steven D.; Caselle, Jennifer E.

    2017-01-01

    For broadly distributed, often overexploited species such as elasmobranchs (sharks and rays), conservation management would benefit from understanding how life history traits change in response to local environmental and ecological factors. However, fishing obfuscates this objective by causing complex and often mixed effects on the life histories of target species. Disentangling the many drivers of life history variability requires knowledge of elasmobranch populations in the absence of fishing, which is rarely available. Here, we describe the growth, maximum size, sex ratios, size at maturity, and offer a direct estimate of survival of an unfished population of grey reef sharks (Carcharhinus amblyrhynchos) using data from an eight year tag-recapture study. We then synthesized published information on the life history of C. amblyrhynchos from across its geographic range, and for the first time, we attempted to disentangle the contribution of fishing from geographic variation in an elasmobranch species. For Palmyra’s unfished C. amblyrhynchos population, the von Bertalanffy growth function (VBGF) growth coefficient k was 0.05 and asymptotic length L∞ was 163.3 cm total length (TL). Maximum size was 175.5 cm TL from a female shark, length at maturity was estimated at 116.7–123.2 cm TL for male sharks, maximum lifespan estimated from VBGF parameters was 18.1 years for both sexes combined, and annual survival was 0.74 year-1. Consistent with findings from studies on other elasmobranch species, we found significant intraspecific variability in reported life history traits of C. amblyrhynchos. However, contrary to what others have reported, we did not find consistent patterns in life history variability as a function of biogeography or fishing. Ultimately, the substantial, but not yet predictable variability in life history traits observed for C. amblyrhynchos across its geographic range suggests that regional management may be necessary to set sustainable harvest

  4. Growth and life history variability of the grey reef shark (Carcharhinus amblyrhynchos) across its range.

    PubMed

    Bradley, Darcy; Conklin, Eric; Papastamatiou, Yannis P; McCauley, Douglas J; Pollock, Kydd; Kendall, Bruce E; Gaines, Steven D; Caselle, Jennifer E

    2017-01-01

    For broadly distributed, often overexploited species such as elasmobranchs (sharks and rays), conservation management would benefit from understanding how life history traits change in response to local environmental and ecological factors. However, fishing obfuscates this objective by causing complex and often mixed effects on the life histories of target species. Disentangling the many drivers of life history variability requires knowledge of elasmobranch populations in the absence of fishing, which is rarely available. Here, we describe the growth, maximum size, sex ratios, size at maturity, and offer a direct estimate of survival of an unfished population of grey reef sharks (Carcharhinus amblyrhynchos) using data from an eight year tag-recapture study. We then synthesized published information on the life history of C. amblyrhynchos from across its geographic range, and for the first time, we attempted to disentangle the contribution of fishing from geographic variation in an elasmobranch species. For Palmyra's unfished C. amblyrhynchos population, the von Bertalanffy growth function (VBGF) growth coefficient k was 0.05 and asymptotic length L∞ was 163.3 cm total length (TL). Maximum size was 175.5 cm TL from a female shark, length at maturity was estimated at 116.7-123.2 cm TL for male sharks, maximum lifespan estimated from VBGF parameters was 18.1 years for both sexes combined, and annual survival was 0.74 year-1. Consistent with findings from studies on other elasmobranch species, we found significant intraspecific variability in reported life history traits of C. amblyrhynchos. However, contrary to what others have reported, we did not find consistent patterns in life history variability as a function of biogeography or fishing. Ultimately, the substantial, but not yet predictable variability in life history traits observed for C. amblyrhynchos across its geographic range suggests that regional management may be necessary to set sustainable harvest

  5. Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species

    PubMed Central

    Young, Emma F; Belchier, Mark; Hauser, Lorenz; Horsburgh, Gavin J; Meredith, Michael P; Murphy, Eugene J; Pascoal, Sonia; Rock, Jennifer; Tysklind, Niklas; Carvalho, Gary R

    2015-01-01

    Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a ‘seascape genetics’ approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts. PMID:26029262

  6. Acts of kindness and acts of novelty affect life satisfaction.

    PubMed

    Buchanan, Kathryn E; Bardi, Anat

    2010-01-01

    The present experiment was designed to establish the effects of acts of kindness and acts of novelty on life satisfaction. Participants aged 18-60 took part on a voluntary basis. They were randomly assigned to perform either acts of kindness, acts of novelty, or no acts on a daily basis for 10 days. Their life satisfaction was measured before and after the 10-day experiment. As expected, performing acts of kindness or acts of novelty resulted in an increase in life satisfaction.

  7. Life History Plasticity of a Tropical Seabird in Response to El Niño Anomalies during Early Life

    PubMed Central

    Ancona, Sergio; Drummond, Hugh

    2013-01-01

    Food shortage and other challenges associated with El Niño Southern Oscillation (ENSO) experienced early in life may have long-term impacts on life history traits, but these potential impacts remain virtually unexplored. By monitoring 2556 blue-footed boobies from 11 cohorts, we showed that birds facing warm water ENSO conditions (and probably low food availability) in the natal year were underweight at fledging, recruited earlier and bred less frequently, but showed no deficit in longevity or breeding success over the first 10 years. Life history impacts of ENSO were substantial when experienced in the prenatal year, the natal year, or the second year of life, and absent when experienced in the third year of life, implying that harsh conditions have greater effects when experienced earlier in life. Sexual differences in impacts depended on the age when warm water conditions were experienced: pre-natal and natal experience, respectively, induced early recruitment and influenced the relationship between age and laying date only in females, whereas second year experience reduced total breeding success only of males. Most surprising were positive transgenerational impacts in females: daughters of females that experienced ENSO conditions in their natal year showed improved breeding success. Developmental plasticity of boobies thus enables them to largely neutralize potential long-term impacts of harsh climatic conditions experienced early in life. PMID:24023760

  8. Diversification and extinction in the history of life.

    PubMed

    Benton, M J

    1995-04-07

    Analysis of the fossil record of microbes, algae, fungi, protists, plants, and animals shows that the diversity of both marine and continental life increased exponentially since the end of the Precambrian. This diversification was interrupted by mass extinctions, the largest of which occurred in the Early Cambrian, Late Ordovician, Late Devonian, Late Permian, Early Triassic, Late Triassic, and end-Cretaceous. Most of these extinctions were experienced by both marine and continental organisms. As for the periodicity of mass extinctions, no support was found: Seven mass extinction peaks in the last 250 million years are spaced 20 to 60 million years apart.

  9. Life lines: An art history of biological research around 1800.

    PubMed

    Bruhn, Matthias

    2011-12-01

    Around 1800, the scientific "illustrator" emerged as a new artistic profession in Europe. Artists were increasingly sought after in order to picture anatomical dissections and microscopic observations and to translate drawings into artworks for books and journals. By training and technical expertise, they introduced a particular kind of knowledge into scientific perception that also shaped the common image of nature. Illustrations of scientific publications, often undervalued as a biased interpretation of facts and subordinate to logic and description, thus convey an 'art history' of science in its own right, relevant both for the understanding of biological thought around 1800 as well as for the development of the arts and their historiography. The article is based on an analysis of botanical treatises produced for the Göttingen Society of Sciences in 1803, during an early phase of microscopic cell research, in order to determine the constitutive role of artistic knowledge and the media employed for the visualization and conceptualization of biological issues.

  10. Seasonal life history trade-offs in two leafwing butterflies: Delaying reproductive development increases life expectancy.

    PubMed

    McElderry, Robert M

    2016-04-01

    Surviving inhospitable periods or seasons may greatly affect fitness. Evidence of this exists in the prevalence of dormant stages in the life cycles of most insects. Here I focused on butterflies with distinct seasonal morphological types (not a genetic polymorphism) in which one morphological type, or form, delays reproduction until favorable conditions return, while the other form develops in an environment that favors direct reproduction. For two butterflies, Anaea aidea and A. andria, I tested the hypothesis that the development of each seasonal form involves a differential allocation of resources to survival at eclosion. I assayed differences in adult longevity among summer and winter forms in either a warm, active environment or a cool, calm environment. Winter form adults lived 40 times longer than summer form but only in calm, cool conditions. The magnitude of this difference provided compelling evidence that the winter form body plan and metabolic strategy (i.e. resource conservatism) favor long term survival. This research suggests that winter form adults maintain lowered metabolic rate, a common feature of diapause, to conserve resources and delay senescence while overwintering.

  11. Pollution Breaks Down the Genetic Architecture of Life History Traits in Caenorhabditis elegans

    PubMed Central

    Dutilleul, Morgan; Goussen, Benoit; Bonzom, Jean-Marc; Galas, Simon; Réale, Denis

    2015-01-01

    When pollution occurs in an environment, populations present suffer numerous negative and immediate effects on their life history traits. Their evolutionary potential to live in a highly stressful environment will depend on the selection pressure strengths and on the genetic structure, the trait heritability, and the genetic correlations between them. If expression of this structure changes in a stressful environment, it becomes necessary to quantify these changes to estimate the evolutionary potential of the population in this new environment. We studied the genetic structure for survival, fecundity, and early and late growth in isogenic lines of a Caenorhabditis elegans population subject to three different environments: a control environment, an environment polluted with uranium, and a high salt concentration environment. We found a heritability decrease in the polluted environments for fecundity and early growth, two traits that were the most heritable in the control environment. The genetic structure of the traits was particularly affected in the uranium polluted environment, probably due to generally low heritability in this environment. This could prevent selection from acting on traits despite the strong selection pressures exerted on them. Moreover, phenotypic traits were more strongly affected in the salt than in the uranium environment and the heritabilities were also lower in the latter environment. Consequently the decrease in heritability was not proportional to the population fitness reduction in the polluted environments. Our results suggest that pollution can alter the genetic structure of a C. elegans population, and thus modify its evolutionary potential. PMID:25714492

  12. Comparative Demography of Skates: Life-History Correlates of Productivity and Implications for Management

    PubMed Central

    Barnett, Lewis A. K.; Winton, Megan V.; Ainsley, Shaara M.; Cailliet, Gregor M.; Ebert, David A.

    2013-01-01

    Age-structured demographic models were constructed based on empirical estimates of longevity and maturity for five deepwater Bering Sea skates to investigate how observed differences in life history parameters affect population growth rates. Monte Carlo simulations were used to incorporate parameter uncertainty. Estimated population growth rates ranged from 1.045 to 1.129 yr−1 and were lower than those reported for other Alaskan skates and most chondrichthyans. Population growth rates of these and other high-latitude skates increased with relative reproductive lifespan, but displayed no significant relationship with body size or depth distribution, suggesting that assemblage shifts may be difficult to predict for data-poor taxa. Elasticity analyses indicated that juvenile and adult survival had greater per-unit effects on population growth rates than did egg-case survival or fecundity. Population growth rate was affected more by uncertainty in age at maturity than maximum age. The results of this study indicate that if skates are deemed to be a management concern, gear modifications or depth-specific effort controls may be effective. PMID:23741442

  13. Plant Fertilization Interacts with Life History: Variation in Stoichiometry and Performance in Nettle-Feeding Butterflies

    PubMed Central

    Audusseau, Hélène; Kolb, Gundula; Janz, Niklas

    2015-01-01

    Variation in food stoichiometry affects individual performance and population dynamics, but it is also likely that species with different life histories should differ in their sensitivity to food stoichiometry. To address this question, we investigated the ability of the three nettle-feeding butterflies (Aglais urticae, Polygonia c-album, and Aglais io) to respond adaptively to induced variation in plant stoichiometry in terms of larval performance. We hypothesized that variation in larval performance between plant fertilization treatments should be functionally linked to species differences in host plant specificity. We found species-specific differences in larval performance between plant fertilization treatments that could not be explained by nutrient limitation. We showed a clear evidence of a positive correlation between food stoichiometry and development time to pupal stage and pupal mass in A. urticae. The other two species showed a more complex response. Our results partly supported our prediction that host plant specificity affects larval sensitivity to food stoichiometry. However, we suggest that most of the differences observed may instead be explained by differences in voltinism (number of generations per year). We believe that the potential of some species to respond adaptively to variation in plant nutrient content needs further attention in the face of increased eutrophication due to nutrient leakage from human activities. PMID:25932628

  14. Plant fertilization interacts with life history: variation in stoichiometry and performance in nettle-feeding butterflies.

    PubMed

    Audusseau, Hélène; Kolb, Gundula; Janz, Niklas

    2015-01-01

    Variation in food stoichiometry affects individual performance and population dynamics, but it is also likely that species with different life histories should differ in their sensitivity to food stoichiometry. To address this question, we investigated the ability of the three nettle-feeding butterflies (Aglais urticae, Polygonia c-album, and Aglais io) to respond adaptively to induced variation in plant stoichiometry in terms of larval performance. We hypothesized that variation in larval performance between plant fertilization treatments should be functionally linked to species differences in host plant specificity. We found species-specific differences in larval performance between plant fertilization treatments that could not be explained by nutrient limitation. We showed a clear evidence of a positive correlation between food stoichiometry and development time to pupal stage and pupal mass in A. urticae. The other two species showed a more complex response. Our results partly supported our prediction that host plant specificity affects larval sensitivity to food stoichiometry. However, we suggest that most of the differences observed may instead be explained by differences in voltinism (number of generations per year). We believe that the potential of some species to respond adaptively to variation in plant nutrient content needs further attention in the face of increased eutrophication due to nutrient leakage from human activities.

  15. Restricted pleiotropy facilitates mutational erosion of major life-history traits.

    PubMed

    Marek, Agnieszka; Korona, Ryszard

    2013-11-01

    Radical shifts to new natural and human made niches can make some functions unneeded and thus exposed to genetic degeneration. Here we ask not about highly specialized and rarely used functions but those relating to major life-history traits, rate of growth, and resistance to prolonged starvation. We found that in yeast each of the two traits was visibly impaired by at least several hundred individual gene deletions. There were relatively few deletions affecting negatively both traits and likely none harming one but improving the other. Functional profiles of gene deletions affecting either growth or survival were strikingly different: the first related chiefly to synthesis of macromolecules whereas the second to maintenance and recycling of cellular structures. The observed pattern of gene indispensability corresponds to that of gene induction, providing a rather rare example of agreement between the results of deletion and expression studies. We conclude that transitions to new environments in which the ability to grow at possibly fastest rate or survive under very long starvation become practically unnecessary can result in rapid erosion of these vital functions because they are coded by many genes constituting large mutational targets and because restricted pleiotropy is unlikely to constrain this process.

  16. Variation in reproductive life history traits between two populations of Blackbanded Darters (Percina nigrofasciata)

    USGS Publications Warehouse

    Hughey, Myra C.; Heins, David C.; Jelks, Howard L.; Ory, Bridget A.; Jordan, Frank

    2012-01-01

    We examined the life history of Blackbanded Darters (Percina nigrofasciata) from two streams in the Choctawhatchee River drainage, Florida, over a three-year study period. Blackbanded Darters from Turkey Creek were longer than fish from Ten Mile Creek; however, size-adjusted clutch and egg sizes were similar between populations. Larger females produced larger clutches, whereas egg size did not vary with female body size. Seasonally, clutch sizes were greater in May than in August. When contrasted with previous studies of Blackbanded Darters in Alabama and Louisiana, the reproductive season of Blackbanded Darters in Florida was unusually long, ceasing for only a few months in late fall. The reproductive season was longer in Turkey Creek than in Ten Mile Creek. Differences in thermal regime among streams may explain differences in life history traits among local and distant populations of Blackbanded Darters. This research, alone and in combination with previous studies of this species, emphasizes two main points. First, it reaffirms that life history studies based on a single locality or conducted at a single point in time may fail to capture the full range of variation in life history traits. Second, it highlights the extensive phenotypic variation found in species with broad geographic ranges. Such species lend themselves to comparative and experimental research on patterns and causes of life history variation.

  17. Extraordinarily rapid life-history divergence between Cryptasterina sea star species

    PubMed Central

    Puritz, Jonathan B.; Keever, Carson C.; Addison, Jason A.; Byrne, Maria; Hart, Michael W.; Grosberg, Richard K.; Toonen, Robert J.

    2012-01-01

    Life history plays a critical role in governing microevolutionary processes such as gene flow and adaptation, as well as macroevolutionary processes such speciation. Here, we use multilocus phylogeographic analyses to examine a speciation event involving spectacular life-history differences between sister species of sea stars. Cryptasterina hystera has evolved a suite of derived life-history traits (including internal self-fertilization and brood protection) that differ from its sister species Cryptasterina pentagona, a gonochoric broadcast spawner. We show that these species have only been reproductively isolated for approximately 6000 years (95% highest posterior density of 905–22 628), and that this life-history change may be responsible for dramatic genetic consequences, including low nucleotide diversity, zero heterozygosity and no gene flow. The rapid divergence of these species rules out some mechanisms of isolation such as adaptation to microhabitats in sympatry, or slow divergence by genetic drift during prolonged isolation. We hypothesize that the large phenotypic differences between species relative to the short divergence time suggests that the life-history differences observed may be direct responses to disruptive selection between populations. We speculate that local environmental or demographic differences at the southern range margin are possible mechanisms of selection driving one of the fastest known marine speciation events. PMID:22810427

  18. Extraordinarily rapid life-history divergence between Cryptasterina sea star species.

    PubMed

    Puritz, Jonathan B; Keever, Carson C; Addison, Jason A; Byrne, Maria; Hart, Michael W; Grosberg, Richard K; Toonen, Robert J

    2012-10-07

    Life history plays a critical role in governing microevolutionary processes such as gene flow and adaptation, as well as macroevolutionary processes such speciation. Here, we use multilocus phylogeographic analyses to examine a speciation event involving spectacular life-history differences between sister species of sea stars. Cryptasterina hystera has evolved a suite of derived life-history traits (including internal self-fertilization and brood protection) that differ from its sister species Cryptasterina pentagona, a gonochoric broadcast spawner. We show that these species have only been reproductively isolated for approximately 6000 years (95% highest posterior density of 905-22 628), and that this life-history change may be responsible for dramatic genetic consequences, including low nucleotide diversity, zero heterozygosity and no gene flow. The rapid divergence of these species rules out some mechanisms of isolation such as adaptation to microhabitats in sympatry, or slow divergence by genetic drift during prolonged isolation. We hypothesize that the large phenotypic differences between species relative to the short divergence time suggests that the life-history differences observed may be direct responses to disruptive selection between populations. We speculate that local environmental or demographic differences at the southern range margin are possible mechanisms of selection driving one of the fastest known marine speciation events.

  19. Life-history variation of a neotropical thrush challenges food limitation theory

    USGS Publications Warehouse

    Ferretti, V.; Llambias, P.E.; Martin, T.E.

    2005-01-01

    Since David Lack first proposed that birds rear as many young as they can nourish, food limitation has been accepted as the primary explanation for variation in clutch size and other life-history traits in birds. The importance of food limitation in life-history variation, however, was recently questioned on theoretical grounds. Here, we show that clutch size differences between two populations of a neotropical thrush were contrary to expectations under Lack's food limitation hypothesis. Larger clutch sizes were found in a population with higher nestling starvation rate (i.e. greater food limitation). We experimentally equalized clutches between populations to verify this difference in food limitation. Our experiment confirmed greater food limitation in the population with larger mean clutch size. In addition, incubation bout length and nestling growth rate were also contrary to predictions of food limitation theory. Our results demonstrate the inability of food limitation to explain differences in several life-history traits: clutch size, incubation behaviour, parental feeding rate and nestling growth rate. These life-history traits were better explained by inter-population differences in nest predation rates. Food limitation may be less important to life history evolution in birds than suggested by traditional theory. ?? 2005 The Royal Society.

  20. Maternal thermal environment induces plastic responses in the reproductive life history of oviparous lizards.

    PubMed

    Ma, Liang; Sun, Bao-Jun; Li, Shu-Ran; Sha, Wei; Du, Wei-Guo

    2014-01-01

    Adaptive plasticity may shift phenotypic traits close to a new optimum for directional selection and probably facilitates adaptive evolution in new environments. However, such plasticity has rarely been reported in life-history evolution, despite overwhelming evidence of life-history variation both among and within species. In this study, the temperatures experienced by gravid females of Scincella modesta were manipulated to identify maternally induced plasticity in reproductive traits and the significance of such changes in the evolution of life history. Consistent with the geographic pattern of life history, the study demonstrated that low temperatures delayed egg oviposition, resulting in a more advanced embryonic developmental stage at oviposition and shorter incubation periods compared with warm temperatures. In addition, females maintained at low temperatures produced larger eggs and hence heavier hatchlings than those at warm temperatures. This study demonstrated that environmental temperatures can induce plastic responses in egg retention and offspring size, and these maternally mediated changes in reproductive life history seem to be adaptive in the light of latitudinal clines of these traits in natural populations.

  1. The contribution of estuary-resident life histories to the return of adult Oncorhynchus kisutch.

    PubMed

    Jones, K K; Cornwell, T J; Bottom, D L; Campbell, L A; Stein, S

    2014-07-01

    This study evaluated estuarine habitat use, life-history composition, growth and survival of four successive broods of coho salmon Oncoryhnchus kisutch in Salmon River, Oregon, U.S.A. Subyearling and yearling O. kisutch used restored and natural estuarine wetlands, particularly in the spring and winter. Stream-reared yearling smolts spent an average of 2 weeks in the estuary growing rapidly before entering the ocean. Emergent fry also entered the estuary in the spring, and some resided in a tidal marsh throughout the summer, even as salinities increased to >20. A significant portion of the summer stream-resident population of juvenile O. kisutch migrated out of the catchment in the autumn and winter and used estuary wetlands and adjacent streams as alternative winter-rearing habitats until the spring when they entered the ocean as yearling smolts. Passive integrated transponder (PIT) tag returns and juvenile life-history reconstructions from otoliths of returning adults revealed that four juvenile life-history types contributed to the adult population. Estuarine-associated life-history strategies accounted for 20-35% of the adults returning to spawn in the four brood years, indicating that a sizable proportion of the total O. kisutch production is ignored by conventional estimates based on stream habitat capacity. Juvenile O. kisutch responses to the reconnection of previously unavailable estuarine habitats have led to greater life-history diversity in the population and reflect greater phenotypic plasticity of the species in the U.S. Pacific Northwest than previously recognized.

  2. Streambed microstructure predicts evolution of development and life history mode in the plethodontid salamander Eurycea tynerensis

    PubMed Central

    Bonett, Ronald M; Chippindale, Paul T

    2006-01-01

    Background Habitat variation strongly influences the evolution of developmentally flexible traits, and may drive speciation and diversification. The plethodontid salamander Eurycea tynerensis is endemic to the geologically diverse Ozark Plateau of south-central North America, and comprises both strictly aquatic paedomorphic populations (achieving reproductive maturity while remaining in the larval form) and more terrestrial metamorphic populations. The switch between developmental modes has occurred many times, but populations typically exhibit a single life history mode. This unique system offers an opportunity to study the specific ecological circumstances under which alternate developmental and life history modes evolve. We use phylogenetic independent contrasts to test for relationships between a key microhabitat feature (streambed sediment) and this major life history polymorphism. Results We find streambed microstructure (sediment particle size, type and degree of sorting) to be highly correlated with life-history mode. Eurycea tynerensis is paedomorphic in streams containing large chert gravel, but metamorphoses in nearby streams containing poorly sorted, clastic material such as sandstone or siltstone. Conclusion Deposits of large chert gravel create loosely associated streambeds, which provide access to subsurface water during dry summer months. Conversely, streambeds composed of more densely packed sandstone and siltstone sediments leave no subterranean refuge when surface water dries, presumably necessitating metamorphosis and use of terrestrial habitats. This represents a clear example of the relationship between microhabitat structure and evolution of a major developmental and life history trait, and has broad implications for the role of localized ecological conditions on larger-scale evolutionary processes. PMID:16512919

  3. NARRATIVE: A short history of my life in science A short history of my life in science

    NASA Astrophysics Data System (ADS)

    Manson, Joseph R.

    2010-08-01

    I was certainly surprised, and felt extremely honored, when Salvador Miret-Artés suggested that he would like to organize this festschrift. Before that day I never anticipated that such an honor would come to me. I would like to thank Salvador for the large amount of time and work he has expended in organizing this special issue, the Editors of Journal of Physics: Condensed Matter for making it possible, and also the contributing authors for their efforts. My family home was outside of Petersburg, Virginia in Dinwiddie County in an area that was, during my youth, largely occupied by small farms. This is a region rich in American history and our earliest ancestors on both sides of the family settled in this area, beginning in the decade after the first Virginia settlement in Jamestown. My father was an engineer and my mother was a former school teacher, and their parents were small business owners. From earliest memories I recall being interested in finding out how things worked and especially learning about the wonders of nature. These interests were fostered by my parents who encouraged such investigations during long walks, visits to friends and relatives, and trips to museums. However, my earliest memory of wanting to become a scientist is associated with a Christmas gift of a chemistry set when I was about ten years old. I was absolutely fascinated by the amazing results that could be achieved with simple chemical reactions and realized then that I wanted to do something in life that would be associated with science. The gift of that small chemistry set developed over the next few years into a serious interest in chemistry, and throughout my junior high-school years I spent nearly all the money I earned doing odd jobs for neighbors on small laboratory equipment and chemical supplies, eventually taking over our old abandoned chicken house and turning it into a small chemistry lab. I remember being somewhat frustrated at the limits, mainly financial, that kept

  4. Predicting responses to climate change requires all life-history stages.

    PubMed

    Zeigler, Sara

    2013-01-01

    In Focus: Radchuk, V., Turlure, C. & Schtickzelle, N. (2013) Each life stage matters: the importance of assessing response to climate change over the complete life cycle in butterflies. Journal of Animal Ecology, 82, 275-285. Population-level responses to climate change depend on many factors, including unexpected interactions among life history attributes; however, few studies examine climate change impacts over complete life cycles of focal species. Radchuk, Turlure & Schtickzelle () used experimental and modelling approaches to predict population dynamics for the bog fritillary butterfly under warming scenarios. Although they found that warming improved fertility and survival of all stages with one exception, populations were predicted to decline because overwintering larvae, whose survival declined with warming, were disproportionately important contributors to population growth. This underscores the importance of considering all life history stages in analyses of climate change's effects on population dynamics.

  5. Life history plasticity and fitness in a caddisfly in response to proximate cues of pond-drying.

    PubMed

    Jannot, Jason E

    2009-08-01

    Pond-drying is a model for understanding the causes of life history variation in metamorphic organisms. However, we know relatively little about how interactions among specific proximate cues of pond-drying affect juvenile life history, how those responses might be mitigated by diet, and the post-metamorphic consequences for adult fitness. I manipulated larval diet, water depth, and water temperature during the aquatic larval stage of a temporary pond-dwelling caddisfly, Limnephilus indivisus. I predicted that shallow depths and warm temperatures (depth x temperature) associated with pond-drying would have negative effects on larval survival, growth, development, adult size, female fecundity, and adult longevity, but that supplementation of the larval diet should mitigate the trade-off between juvenile growth and pre-reproductive mortality risk by ameliorating the negative effects of pond-drying (diet x depth, diet x temperature) on these traits. Larval survival was enhanced by diet supplementation but was not affected by depth or temperature. Larval diet and water temperatures acted independently on growth, development, and female size, and growth rates were higher when larval diets were supplemented relative to ambient diets; development times were shorter when temperatures were warmer relative to colder; adult females were larger when larvae were fed a supplemented diet but smaller when reared in warm water. Larval growth and development were not affected by depth, but female size was reduced under shallow relative to deep conditions. Female longevity and fecundity were affected by the larval diet x female size interaction. Surprisingly, this was independent of the depth x temperature interaction on female longevity and fecundity suggesting that reductions in adult fitness due to juvenile abiotic conditions can be independent of size-at-maturity. Future studies should quantify the effect of proximate cues of pond-drying on juvenile survival and life history as

  6. Life-history evolution and the microevolution of intermediary metabolism: activities of lipid-metabolizing enzymes in life-history morphs of a wing-dimorphic cricket.

    PubMed

    Zera, Anthony J; Zhao, Zhangwu

    2003-03-01

    Although a considerable amount of information is available on the ecology, genetics, and physiology of life-history traits, much more limited data are available on the biochemical and genetic correlates of life-history variation within species. Specific activities of five enzymes of lipid biosynthesis and two enzymes of amino acid catabolism were compared among lines selected for flight-capable (LW[f]) versus flightless (SW) morphs of the cricket Gryllus firmus. These morphs, which exist in natural populations, differ genetically in ovarian growth (100-400% higher in SW) and aspects of flight capability including the size of wings and flight muscles, and the concentration of triglyceride flight fuel (40% greater in LW[f]). Consistently higher activity of each enzyme in LW(f) versus SW-selected lines, and strong co-segregation between morph and enzyme activity, demonstrated genetically based co-variance between wing morph and enzyme activity. Developmental profiles of enzyme activities strongly paralleled profiles of triglyceride accumulation during adulthood and previous measures of in vivo lipid biosynthesis. These data strongly imply that genetically based elevation in activities of lipogenic enzymes, and enzymes controlling the conversion of amino acids into lipids, is an important cause underlying the elevated accumulation of triglyceride in the LW(f) morph, a key biochemical component of the trade-off between elevated early fecundity and flight capability. Global changes in lipid and amino-acid metabolism appear to have resulted from microevolutionary alteration of regulators of metabolism. Finally, strong genotype x environment (diet) interactions were observed for most enzyme activities. Future progress in understanding the functional causes of life-history evolution requires a more detailed synthesis of the fields of life-history evolution and metabolic biochemistry. Wing polymorphism is a powerful experimental model in such integrative studies.

  7. Brief Self-Report Scales Assessing Life History Dimensions of Mating and Parenting Effort.

    PubMed

    Kruger, Daniel J

    2017-01-01

    Life history theory (LHT) is a powerful evolutionary framework for understanding physiological, psychological, and behavioral variation both between and within species. Researchers and theorists are increasingly integrating LHT into evolutionary psychology, as it provides a strong foundation for research across many topical areas. Human life history variation has been represented in psychological and behavioral research in several ways, including indicators of conditions in the developmental environment, indicators of conditions in the current environment, and indicators of maturation and life milestones (e.g., menarche, initial sexual activity, first pregnancy), and in self-report survey scale measures. Survey scale measures have included constructs such as time perspective and future discounting, although the most widely used index is a constellation of indicators assessing the K-factor, thought to index general life history speed (from fast to slow). The current project examined the utility of two brief self-report survey measures assessing the life history dimensions of mating effort and parenting effort with a large undergraduate sample in the United States. Consistent with the theory, items reflected two inversely related dimensions. In regressions including the K-factor, the Mating Effort Scale proved to be a powerful predictor of other constructs and indicators related to life history variation. The Parenting Effort Scale had less predictive power overall, although it explained unique variance across several constructs and was the only unique predictor of the number of long-term (serious and committed) relationships. These scales may be valuable additions to self-report survey research projects examining life history variation.

  8. The life histories of American stepfathers in evolutionary perspective.

    PubMed

    Anderson, K G

    2000-12-01

    This paper presents an analysis of the characteristics of men who become stepfathers, and their subsequent fertility patterns and lifetime reproductive success. Because women who already have children are ranked lower in the marriage market than women without children, men who marry women with children (e.g., stepfathers) are likely to have lower rankings in the marriage market as well. Using retrospective fertility and marital histories from the Panel Study of Income Dynamics (PSID), I show that men who become stepfathers have lower levels of education, less income, and are more likely to have been divorced before and to already have children, all characteristics that lower their rankings in the marriage market. Men with one or two stepchildren are just as likely to have children within a marriage as non-stepfathers, although men with three stepchildren show decreased fertility. Among men age 45 and older, stepfathers have lower lifetime fertility than non-stepfathers, although the difference disappears when men's age at first marriage is controlled for. Additionally, stepfathers have significantly higher fertility than men who never marry. The results suggest that some men become stepfathers to procure mates and fertility benefits that they would otherwise have been unlikely to obtain; for these men, raising other men's children serves as a form of mating effort.

  9. Oxygen: Key for Life but Enemy of the History of Life.

    NASA Astrophysics Data System (ADS)

    Best, M.

    2004-05-01

    a complex of environmental gradients, with oxygen and other essential parameters varying among environments. As a function of physiological limits, environments vary in the density and diversity of biota that they contain. Biological remains are part of the resources of an ecosystem with tissues as sources of organic carbon, skeletons as potential substrates and eventually as chemical ions (particularly in marine settings). So, the more healthy the community, the more they are busy recycling and obliterating any record of previous generations/communities. Similarly, for carbonate burial, regions of the highest carbonate production are likely also regions of the highest carbonate recycling. Lest this be taken as an excuse to dismiss the fossil record as biased, we would no more think of doing so than with historical or archeological records, despite the fact that those preferentially record histories of the victors, the wealthy, and the literate. Just as we look beyond well preserved accounts of life at a monastery for clues of life in urban medieval Europe, so should we look beyond well preserved fossils to glean what paleo-biological and environmental clues we can from less than beautifully preserved fossils and the sediments that contain them.

  10. Spatiotemporal Object History Affects the Selection of Task-Relevant Properties

    ERIC Educational Resources Information Center

    Schreij, Daniel; Olivers, Christian N. L.

    2013-01-01

    For stable perception, we maintain mental representations of objects across space and time. What information is linked to such a representation? In this study, we extended our work showing that the spatiotemporal history of an object affects the way the object is attended the next time it is encountered. Observers conducted a visual search for a…

  11. Variation in seed germination of 134 common species on the eastern Tibetan Plateau: phylogenetic, life history and environmental correlates.

    PubMed

    Xu, Jing; Li, Wenlong; Zhang, Chunhui; Liu, Wei; Du, Guozhen

    2014-01-01

    Seed germination is a crucial stage in the life history of a species because it represents the pathway from adult to offspring, and it can affect the distribution and abundance of species in communities. In this study, we examined the effects of phylogenetic, life history and environmental factors on seed germination of 134 common species from an alpine/subalpine meadow on the eastern Tibetan Plateau. In one-way ANOVAs, phylogenetic groups (at or above order) explained 13.0% and 25.9% of the variance in germination percentage and mean germination time, respectively; life history attributes, such as seed size, dispersal mode, explained 3.7%, 2.1% of the variance in germination percentage and 6.3%, 8.7% of the variance in mean germination time, respectively; the environmental factors temperature and habitat explained 4.7%, 1.0% of the variance in germination percentage and 13.5%, 1.7% of the variance in mean germination time, respectively. Our results demonstrated that elevated temperature would lead to a significant increase in germination percentage and an accelerated germination. Multi-factorial ANOVAs showed that the three major factors contributing to differences in germination percentage and mean germination time in this alpine/subalpine meadow were phylogenetic attributes, temperature and seed size (explained 10.5%, 4.7% and 1.4% of the variance in germination percentage independently, respectively; and explained 14.9%, 13.5% and 2.7% of the variance in mean germination time independently, respectively). In addition, there were strong associations between phylogenetic group and life history attributes, and between life history attributes and environmental factors. Therefore, germination variation are constrained mainly by phylogenetic inertia in a community, and seed germination variation correlated with phylogeny is also associated with life history attributes, suggesting a role of niche adaptation in the conservation of germination variation within lineages

  12. The Life History Calendar Method and Multilevel Modeling: Application to Research on Intimate Partner Violence.

    PubMed

    Yoshihama, Mieko; Bybee, Deborah

    2011-03-01

    Intimate partner violence (IPV) is prevalent and often recurrent in women's lives. To better understand the changing risk of IPV over the life course, which could guide more effective policies and program responses, methodological innovations are needed. Life History Calendar methods enhance respondents' recall of the timing of specific types of IPV experienced over the life course. Multilevel modeling provides a way to analyze individual and collective trajectories and examine covariates of IPV risk. We apply these complementary methods to examine IPV trajectories for a sample of women of Filipina descent living in the United States, examining life course timing and cohort effects.

  13. Evolution of dispersal and life history interact to drive accelerating spread of an invasive species.

    PubMed

    Perkins, T Alex; Phillips, Benjamin L; Baskett, Marissa L; Hastings, Alan

    2013-08-01

    Populations on the edge of an expanding range are subject to unique evolutionary pressures acting on their life-history and dispersal traits. Empirical evidence and theory suggest that traits there can evolve rapidly enough to interact with ecological dynamics, potentially giving rise to accelerating spread. Nevertheless, which of several evolutionary mechanisms drive this interaction between evolution and spread remains an open question. We propose an integrated theoretical framework for partitioning the contributions of different evolutionary mechanisms to accelerating spread, and we apply this model to invasive cane toads in northern Australia. In doing so, we identify a previously unrecognised evolutionary process that involves an interaction between life-history and dispersal evolution during range shift. In roughly equal parts, life-history evolution, dispersal evolution and their interaction led to a doubling of distance spread by cane toads in our model, highlighting the potential importance of multiple evolutionary processes in the dynamics of range expansion.

  14. Fine scale relationships between sex, life history, and dispersal of masu salmon

    USGS Publications Warehouse

    Kitanishi, Shigeru; Yamamoto, Toshiaki; Koizumi, Itsuro; Dunham, Jason B.; Higashi, Seigo

    2012-01-01

    Identifying the patterns and processes driving dispersal is critical for understanding population structure and dynamics. In many organisms, sex-biased dispersal is related to the type of mating system. Considerably less is known about the influence of life history variability on dispersal. Here we investigated patterns of dispersal in masu salmon (Oncorhynchus masou) to evaluate influences of sex and life history on dispersal. As expected, assignment tests and isolation by distance analysis revealed that dispersal of marine-migratory masu salmon was male-biased. However, dispersal of resident and migratory males did not follow our expectation and marine-migratory individuals dispersed more than residents. This may be because direct competition between marine-migratory and resident males is weak or that the cost of dispersal is smaller for marine-migratory individuals. This study revealed that both sex and migratory life history influence patterns of dispersal at a local scale in masu salmon.

  15. Life history and status of shortnose sturgeon (Acipenser brevirostrum) in the Potomac River

    USGS Publications Warehouse

    Kieffer, Micah

    2009-01-01

    We collected the first life history information on shortnose sturgeon (Acipenser brevirostrum) in any of the rivers to Chesapeake Bay, the geographic center of the species range. In the Potomac River, two telemetry-tagged adult females used 124 km of river: a saltwater/freshwater reach at river km (rkm) 63-141 was the foraging-wintering concentration area, and one female migrated to spawn at rkm 187 in Washington, DC. The spawning migration explained the life history context of an adult captured 122 years ago in Washington, DC, supporting the idea that a natal population once lived in the river. Repeated homing migrations to foraging and wintering areas suggested the adults were residents, not transient coastal migrants. All habitats that adults need to complete life history are present in the river. The Potomac River shortnose sturgeon offers a rare opportunity to learn about the natural rebuilding of a sturgeon population.

  16. Life history and status of shortnose sturgeon (Acipenser brevirostrum) in the potomac river

    USGS Publications Warehouse

    Kynard, B.; Breece, M.; Atcheson, M.; Kieffer, M.; Mangold, M.

    2009-01-01

    We collected the first life history information on shortnose sturgeon (Acipenser brevirostrum) in any of the rivers to Chesapeake Bay, the geographic center of the species range. In the Potomac River, two telemetry-tagged adult females used 124 km of river: A saltwater/freshwater reach at river km (rkm) 63-141 was the foraging-wintering concentration area, and one female migrated to spawn at rkm 187 in Washington, DC. The spawning migration explained the life history context of an adult captured 122 years ago in Washington, DC, supporting the idea that a natal population once lived in the river. Repeated homing migrations to foraging and wintering areas suggested the adults were residents, not transient coastal migrants. All habitats that adults need to complete life history are present in the river. The Potomac River shortnose sturgeon offers a rare opportunity to learn about the natural rebuilding of a sturgeon population. ?? 2009 Blackwell Verlag, Berlin.

  17. Sex-specific local life-history adaptation in surface- and cave-dwelling Atlantic mollies (Poecilia mexicana)

    PubMed Central

    Riesch, Rüdiger; Reznick, David N.; Plath, Martin; Schlupp, Ingo

    2016-01-01

    Cavefishes have long been used as model organisms showcasing adaptive diversification, but does adaptation to caves also facilitate the evolution of reproductive isolation from surface ancestors? We raised offspring of wild-caught surface- and cave-dwelling ecotypes of the neotropical fish Poecilia mexicana to sexual maturity in a 12-month common garden experiment. Fish were raised under one of two food regimes (high vs. low), and this was crossed with differences in lighting conditions (permanent darkness vs. 12:12 h light:dark cycle) in a 2 × 2 factorial design, allowing us to elucidate potential patterns of local adaptation in life histories. Our results reveal a pattern of sex-specific local life-history adaptation: Surface molly females had the highest fitness in the treatment best resembling their habitat of origin (high food and a light:dark cycle), and suffered from almost complete reproductive failure in darkness, while cave molly females were not similarly affected in any treatment. Males of both ecotypes, on the other hand, showed only weak evidence for local adaptation. Nonetheless, local life-history adaptation in females likely contributes to ecological diversification in this system and other cave animals, further supporting the role of local adaptation due to strong divergent selection as a major force in ecological speciation. PMID:26960566

  18. Sex-specific local life-history adaptation in surface- and cave-dwelling Atlantic mollies (Poecilia mexicana).

    PubMed

    Riesch, Rüdiger; Reznick, David N; Plath, Martin; Schlupp, Ingo

    2016-03-10

    Cavefishes have long been used as model organisms showcasing adaptive diversification, but does adaptation to caves also facilitate the evolution of reproductive isolation from surface ancestors? We raised offspring of wild-caught surface- and cave-dwelling ecotypes of the neotropical fish Poecilia mexicana to sexual maturity in a 12-month common garden experiment. Fish were raised under one of two food regimes (high vs. low), and this was crossed with differences in lighting conditions (permanent darkness vs. 12:12 h light:dark cycle) in a 2 × 2 factorial design, allowing us to elucidate potential patterns of local adaptation in life histories. Our results reveal a pattern of sex-specific local life-history adaptation: Surface molly females had the highest fitness in the treatment best resembling their habitat of origin (high food and a light:dark cycle), and suffered from almost complete reproductive failure in darkness, while cave molly females were not similarly affected in any treatment. Males of both ecotypes, on the other hand, showed only weak evidence for local adaptation. Nonetheless, local life-history adaptation in females likely contributes to ecological diversification in this system and other cave animals, further supporting the role of local adaptation due to strong divergent selection as a major force in ecological speciation.

  19. Life history correlates of fecal bacterial species richness in a wild population of the blue tit Cyanistes caeruleus.

    PubMed

    Benskin, Clare McW H; Rhodes, Glenn; Pickup, Roger W; Mainwaring, Mark C; Wilson, Kenneth; Hartley, Ian R

    2015-02-01

    Very little is known about the normal gastrointestinal flora of wild birds, or how it might affect or reflect the host's life-history traits. The aim of this study was to survey the species richness of bacteria in the feces of a wild population of blue tits Cyanistes caeruleus and to explore the relationships between bacterial species richness and various life-history traits, such as age, sex, and reproductive success. Using PCR-TGGE, 55 operational taxonomic units (OTUs) were identified in blue tit feces. DNA sequencing revealed that the 16S rRNA gene was amplified from a diverse range of bacteria, including those that shared closest homology with Bacillus licheniformis, Campylobacter lari, Pseudomonas spp., and Salmonella spp. For adults, there was a significant negative relationship between bacterial species richness and the likelihood of being detected alive the following breeding season; bacterial richness was consistent across years but declined through the breeding season; and breeding pairs had significantly more similar bacterial richness than expected by chance alone. Reduced adult survival was correlated with the presence of an OTU most closely resembling C. lari; enhanced adult survival was associated with an OTU most similar to Arthrobacter spp. For nestlings, there was no significant change in bacterial species richness between the first and second week after hatching, and nestlings sharing the same nest had significantly more similar bacterial richness. Collectively, these results provide compelling evidence that bacterial species richness was associated with several aspects of the life history of their hosts.

  20. Competition alters life history and increases the relative fecundity of crop-wild radish hybrids (Raphanus spp.).

    PubMed

    Campbell, Lesley G; Snow, Allison A

    2007-01-01

    The evolutionary impact of crop-to-wild gene flow depends on the fitness of hybrids under natural, competitive conditions. Here, we measured the performance of third-generation (F3) radish hybrids (Raphanus raphanistrum x Raphanus sativus) and weedy R. raphanistrum to understand how competitive interactions affect life history and relative fecundity. Three wild and three F1 crop-wild hybrid radish populations were established in semi-natural, agricultural conditions in Michigan, USA. The effects of competition on life-history traits and fecundity of F3 progeny were measured 2 yr later in a common garden experiment. Third-generation hybrid plants generally produced fewer seeds per fruit and set fewer fruits per flower than wild plants, resulting in lower lifetime fecundity. With increasing competition, age at reproduction was delayed, the relative number of seeds per fruit was reduced in wild plants and differences between hybrid and wild fecundity diminished. Competition may enhance the fecundity of advanced-generation hybrids relative to wild plants by reducing differences in life history, potentially promoting the introgression of crop alleles into weed populations.

  1. Life-history traits predict perennial species response to fire in a desert ecosystem

    PubMed Central

    Shryock, Daniel F; DeFalco, Lesley A; Esque, Todd C

    2014-01-01

    The Mojave Desert of North America has become fire-prone in recent decades due to invasive annual grasses that fuel wildfires following years of high rainfall. Perennial species are poorly adapted to fire in this system, and post-fire shifts in species composition have been substantial but variable across community types. To generalize across a range of conditions, we investigated whether simple life-history traits could predict how species responded to fire. Further, we classified species into plant functional types (PFTs) based on combinations of life-history traits and evaluated whether these groups exhibited a consistent fire-response. Six life-history traits varied significantly between burned and unburned areas in short (up to 4 years) or long-term (up to 52 years) post-fire datasets, including growth form, lifespan, seed size, seed dispersal, height, and leaf longevity. Forbs and grasses consistently increased in abundance after fire, while cacti were reduced and woody species exhibited a variable response. Woody species were classified into three PFTs based on combinations of life-history traits. Species in Group 1 increased in abundance after fire and were characterized by short lifespans, small, wind-dispersed seeds, low height, and deciduous leaves. Species in Group 2 were reduced by fire and distinguished from Group 1 by longer lifespans and evergreen leaves. Group 3 species, which also decreased after fire, were characterized by long lifespans, large non-wind dispersed seeds, and taller heights. Our results show that PFTs based on life-history traits can reliably predict the responses of most species to fire in the Mojave Desert. Dominant, long-lived species of this region possess a combination of traits limiting their ability to recover, presenting a clear example of how a novel disturbance regime may shift selective environmental pressures to favor alternative life-history strategies. PMID:25247062

  2. Beware of Primate Life History Data: A Plea for Data Standards and a Repository

    PubMed Central

    Borries, Carola; Gordon, Adam D.; Koenig, Andreas

    2013-01-01

    Life history variables such as the age at first reproduction and the interval between consecutive births are measures of investment in growth and reproduction in a particular population or species. As such they allow for meaningful comparisons of the speed of growth and reproduction between species and between larger taxa. Especially in primates such life history research has far reaching implications and has led for instance to the “grandmother hypothesis”. Other links have been proposed with respect to dietary adaptations: Because protein is essential for growth and one of the primary sources of protein, leaves, occurs much less seasonally than fruits, it has been predicted that folivorous primates should grow faster compared to frugivorous ones. However, when comparing folivorous Asian colobines with frugivorous Asian macaques we recently documented a longer, instead of a shorter gestation length in folivores while age at first reproduction and interbirth interval did not differ. This supports earlier findings for Malagasy lemurs in which all life history variables tested were significantly longer in folivores compared to frugivores. Wondering why these trends were not apparent sooner, we tried to reconstruct our results for Asian primates with data from four popular life history compilations. However, this attempt failed; even the basic, allometric relationship with adult female body mass that is typical for life history variables could not be recovered. This negative result hints at severe problems with data quality. Here we show that data quality can be improved significantly by standardizing the variables and by controlling for factors such as nutritional conditions or infant mortality. Ideally, in the future, revised primate life history data should be collated in a central database accessible to everybody. In the long run such an initiative should be expanded to include all mammalian species. PMID:23826232

  3. Life history and evolutionary adaptation of Pacific salmon and its application in management

    SciTech Connect

    Wevers, M.J.

    1993-01-01

    An approach to understanding and managing anadromous salmon, steelhead, and sea-run cutthroat trout (Oncorhynchus spp.) based on life history and evolutionary adaptive capacities of species and stocks is presented. Species, stocks, and local populations are viewed as systems that are continuously adapting to changing environmental conditions. They have the potential capacity to evolve in different ways in different environments through both life history and evolutionary adaptation. Habitat organization forms a template for genus, species, stock, and local population life history organization. Harvesting, habitat alteration resulting from land use practices and other human activities can alter the organization and adaptive capacities of species and stocks, and thus their long term persistence. The adaptive capacity of Oncorhynchus relative to its habitat and management environment is examined at the species, stock, and local population levels. Life history characteristics of representative stocks and local populations are analyzed using Detrended Correspondence Analysis (DECORANA). Fresh water migration distance and latitude are used to [open quotes]explain[close quotes] ordination patterns of Oncorhynchus species in the North Pacific Basin. Fresh water migration difficulty and mean annual runoff as used to interpret life history patterns of Columbia Basin chinook salmon stocks. Upstream migration difficulty and fall water temperatures are used to explain the ordination patterns of local populations of Willamette spring chinook salmon. Fishery management practices are examined in terms of their impacts on the organization and adaptive capacity of species, stocks, and local populations of Oncorhynchus. Management generalizations and guidelines derived from the life history theory are applied to management of Willamette spring chinook salmon.

  4. Life-history traits predict perennial species response to fire in a desert ecosystem.

    PubMed

    Shryock, Daniel F; DeFalco, Lesley A; Esque, Todd C

    2014-08-01

    The Mojave Desert of North America has become fire-prone in recent decades due to invasive annual grasses that fuel wildfires following years of high rainfall. Perennial species are poorly adapted to fire in this system, and post-fire shifts in species composition have been substantial but variable across community types. To generalize across a range of conditions, we investigated whether simple life-history traits could predict how species responded to fire. Further, we classified species into plant functional types (PFTs) based on combinations of life-history traits and evaluated whether these groups exhibited a consistent fire-response. Six life-history traits varied significantly between burned and unburned areas in short (up to 4 years) or long-term (up to 52 years) post-fire datasets, including growth form, lifespan, seed size, seed dispersal, height, and leaf longevity. Forbs and grasses consistently increased in abundance after fire, while cacti were reduced and woody species exhibited a variable response. Woody species were classified into three PFTs based on combinations of life-history traits. Species in Group 1 increased in abundance after fire and were characterized by short lifespans, small, wind-dispersed seeds, low height, and deciduous leaves. Species in Group 2 were reduced by fire and distinguished from Group 1 by longer lifespans and evergreen leaves. Group 3 species, which also decreased after fire, were characterized by long lifespans, large non-wind dispersed seeds, and taller heights. Our results show that PFTs based on life-history traits can reliably predict the responses of most species to fire in the Mojave Desert. Dominant, long-lived species of this region possess a combination of traits limiting their ability to recover, presenting a clear example of how a novel disturbance regime may shift selective environmental pressures to favor alternative life-history strategies.

  5. The Conservation and Management of Tunas and Their Relatives: Setting Life History Research Priorities

    PubMed Central

    Juan-Jordá, Maria José; Mosqueira, Iago; Freire, Juan; Dulvy, Nicholas K.

    2013-01-01

    Scombrids (tunas, bonitos, Spanish mackerels and mackerels) support important fisheries in tropical, subtropical and temperate waters around the world, being one of the most economically- and socially-important marine species globally. Their sustainable exploitation, management and conservation depend on accurate life history information for the development of quantitative fisheries stock assessments, and in the fishery data-poor situations for the identification of vulnerable species. Here, we assemble life history traits (maximum size, growth, longevity, maturity, fecundity, spawning duration and spawning interval) for the 51 species of scombrids globally. We identify major biological gaps in knowledge and prioritize life history research needs in scombrids based on their biological gaps in knowledge, the importance of their fisheries and their current conservation status according to the International Union for Conservation of Nature Red List. We find that the growth and reproductive biology of tunas and mackerel species have been more extensively studied than for Spanish mackerels and bonitos, although there are notable exceptions in all groups. We also reveal that reproductive biology of species, particular fecundity, is the least studied biological aspect in scombrids. We identify two priority groups, including 32 species of scombrids, and several populations of principal market tunas, for which life history research should be prioritized following the species-specific life history gaps identified in this study in the coming decades. By highlighting the important gaps in biological knowledge and providing a priority setting for life history research in scombrid species this study provides guidance for management and conservation and serves as a guide for biologists and resource managers interested in the biology, ecology, and management of scombrid species. PMID:23950930

  6. The conservation and management of tunas and their relatives: setting life history research priorities.

    PubMed

    Juan-Jordá, Maria José; Mosqueira, Iago; Freire, Juan; Dulvy, Nicholas K

    2013-01-01

    Scombrids (tunas, bonitos, Spanish mackerels and mackerels) support important fisheries in tropical, subtropical and temperate waters around the world, being one of the most economically- and socially-important marine species globally. Their sustainable exploitation, management and conservation depend on accurate life history information for the development of quantitative fisheries stock assessments, and in the fishery data-poor situations for the identification of vulnerable species. Here, we assemble life history traits (maximum size, growth, longevity, maturity, fecundity, spawning duration and spawning interval) for the 51 species of scombrids globally. We identify major biological gaps in knowledge and prioritize life history research needs in scombrids based on their biological gaps in knowledge, the importance of their fisheries and their current conservation status according to the International Union for Conservation of Nature Red List. We find that the growth and reproductive biology of tunas and mackerel species have been more extensively studied than for Spanish mackerels and bonitos, although there are notable exceptions in all groups. We also reveal that reproductive biology of species, particular fecundity, is the least studied biological aspect in scombrids. We identify two priority groups, including 32 species of scombrids, and several populations of principal market tunas, for which life history research should be prioritized following the species-specific life history gaps identified in this study in the coming decades. By highlighting the important gaps in biological knowledge and providing a priority setting for life history research in scombrid species this study provides guidance for management and conservation and serves as a guide for biologists and resource managers interested in the biology, ecology, and management of scombrid species.

  7. Relationships between Endocrine Traits and Life Histories in Wild Animals: Insights, Problems, and Potential Pitfalls.

    PubMed

    Dantzer, Ben; Westrick, Sarah E; van Kesteren, Freya

    2016-08-01

    The endocrine mechanisms causing variation and plasticity in life history traits (e.g., development time, mass at birth/hatching, rate of postnatal growth, age or size at sexual maturity, litter or clutch size, annual survival, and lifespan) or fitness (annual or lifetime reproductive success) have recently garnered considerable interest. We review three issues facing studies that quantify relationships between endocrine traits and life histories or measures of fitness and describe possible solutions using insights from evolutionary ecology. We focus in particular on the steroid hormones glucocorticoids that are involved in the vertebrate neuroendocrine stress response. First, context-dependent associations between endocrine traits and life histories or fitness are widespread, and therefore, it is important to quantify how intrinsic or extrinsic factors modify these relationships. Second, studies in evolutionary endocrinology may aspire to quantify patterns of natural selection on endocrine traits, but this may not tell us how they influence fitness. Studies that also identify the actual targets of selection that the endocrine traits are influencing will be very useful. Third, environmental or intrinsic factors can cause co-variance between endocrine traits and life histories or fitness. This is problematic for interpreting the potential evolutionary consequences of selection on endocrine traits, but it can also produce divergent answers for relationships between endocrine traits and life histories or fitness depending upon whether the data are analyzed in an among- or within-year framework. Future long-term studies following uniquely marked individuals over their lifetime (longitudinal individual-based approach) in combination with experimental manipulations of the endocrine traits or environmental factors influencing both endocrine traits and life histories or fitness may help to produce new insights in evolutionary endocrinology despite these issues. This is an

  8. Dissecting molecular stress networks: identifying nodes of divergence between life-history phenotypes.

    PubMed

    Schwartz, Tonia S; Bronikowski, Anne M

    2013-02-01

    The complex molecular network that underlies physiological stress response is comprised of nodes (proteins, metabolites, mRNAs, etc.) whose connections span cells, tissues and organs. Variable nodes are points in the network upon which natural selection may act. Thus, identifying variable nodes will reveal how this molecular stress network may evolve among populations in different habitats and how it might impact life-history evolution. Here, we use physiological and genetic assays to test whether laboratory-born juveniles from natural populations of garter snakes (Thamnophis elegans), which have diverged in their life-history phenotypes, vary concomitantly at candidate nodes of the stress response network, (i) under unstressed conditions and (ii) in response to an induced stress. We found that two common measures of stress (plasma corticosterone and liver gene expression of heat shock proteins) increased under stress in both life-history phenotypes. In contrast, the phenotypes diverged at four nodes both under unstressed conditions and in response to stress: circulating levels of reactive oxygen species (superoxide, H(2)O(2)); liver gene expression of GPX1 and erythrocyte DNA damage. Additionally, allele frequencies for SOD2 diverge from neutral markers, suggesting diversifying selection on SOD2 alleles. This study supports the hypothesis that these life-history phenotypes have diverged at the molecular level in how they respond to stress, particularly in nodes regulating oxidative stress. Furthermore, the differences between the life-history phenotypes were more pronounced in females. We discuss the responses to stress in the context of the associated life-history phenotype and the evolutionary pressures thought to be responsible for divergence between the phenotypes.

  9. Life-history traits predict perennial species response to fire in a desert ecosystem

    USGS Publications Warehouse

    Shryock, Daniel F.; DeFalco, Lesley A.; Esque, Todd C.

    2014-01-01

    The Mojave Desert of North America has become fire-prone in recent decades due to invasive annual grasses that fuel wildfires following years of high rainfall. Perennial species are poorly adapted to fire in this system, and post-fire shifts in species composition have been substantial but variable across community types. To generalize across a range of conditions, we investigated whether simple life-history traits could predict how species responded to fire. Further, we classified species into plant functional types (PFTs) based on combinations of life-history traits and evaluated whether these groups exhibited a consistent fire-response. Six life-history traits varied significantly between burned and unburned areas in short (up to 4 years) or long-term (up to 52 years) post-fire datasets, including growth form, lifespan, seed size, seed dispersal, height, and leaf longevity. Forbs and grasses consistently increased in abundance after fire, while cacti were reduced and woody species exhibited a variable response. Woody species were classified into three PFTs based on combinations of life-history traits. Species in Group 1 increased in abundance after fire and were characterized by short lifespans, small, wind-dispersed seeds, low height, and deciduous leaves. Species in Group 2 were reduced by fire and distinguished from Group 1 by longer lifespans and evergreen leaves. Group 3 species, which also decreased after fire, were characterized by long lifespans, large non-wind dispersed seeds, and taller heights. Our results show that PFTs based on life-history traits can reliably predict the responses of most species to fire in the Mojave Desert. Dominant, long-lived species of this region possess a combination of traits limiting their ability to recover, presenting a clear example of how a novel disturbance regime may shift selective environmental pressures to favor alternative life-history strategies.

  10. Chronic Ischemic Heart Disease Affects Health Related Quality of Life

    PubMed Central

    Goreishi, Abolfazl; Shajari, Zahra; Mohammadi, Zeinab

    2012-01-01

    Background Chronic diseases endanger not only physical health but also psychological and social health of patient. Thus, evaluation of such patients for psychological treatment decisions is very important. Method This is a descriptive study that was performed with 50 chronic patients (ischemic heart disease) selected from Valiasr and Mousavi at cardiac wards in Zanjan Province. They were given three types of questionnaire: demographic, WHOQOL, and Zung depression and anxiety index. The information was statically analyzed by frequency chart, central indexes, dispersion, Chi-Square and t tests, Pearson’s correlation index (P < 0.05). Results The average of quality of life in all patients were calculated as was respectively 12.19, 11.98, 12.08, and 12.4 in physical, psychological, social and environmental domains respectively, 68 percent of total number of the patients had various degrees of anxiety and 78 percent of them had various degrees of depression. There was a significant relationship between the life quality average in all domains and anxiety intensity and depression intensity (P < 0.05) and there was a significant relationship between life quality average in all domains and income (P < 0.05). Conclusion As the level of depression and anxiety goes up, quality of life decreases pointing out that they have a reverse relationship. Depression and anxiety are one of the most significant factors of quality of life among other variables. Regarding specific conditions of the treatment, it is necessary to pay special attention to psychological aspects.

  11. Life history and demographic drivers of reservoir competence for three tick-borne zoonotic pathogens.

    PubMed

    Ostfeld, Richard S; Levi, Taal; Jolles, Anna E; Martin, Lynn B; Hosseini, Parviez R; Keesing, Felicia

    2014-01-01

    Animal and plant species differ dramatically in their quality as hosts for multi-host pathogens, but the causes of this variation are poorly understood. A group of small mammals, including small rodents and shrews, are among the most competent natural reservoirs for three tick-borne zoonotic pathogens, Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum, in eastern North America. For a group of nine commonly-infected mammals spanning >2 orders of magnitude in body mass, we asked whether life history features or surrogates for (unknown) encounter rates with ticks, predicted reservoir competence for each pathogen. Life history features associated with a fast pace of life generally were positively correlated with reservoir competence. However, a model comparison approach revealed that host population density, as a proxy for encounter rates between hosts and pathogens, generally received more support than did life history features. The specific life history features and the importance of host population density differed somewhat between the different pathogens. We interpret these results as supporting two alternative but non-exclusive hypotheses for why ecologically widespread, synanthropic species are often the most competent reservoirs for multi-host pathogens. First, multi-host pathogens might adapt to those hosts they are most likely to experience, which are likely to be the most abundant and/or frequently bitten by tick vectors. Second, species with fast life histories might allocate less to certain immune defenses, which could increase their reservoir competence. Results suggest that of the host species that might potentially be exposed, those with comparatively high population densities, small bodies, and fast pace of life will often be keystone reservoirs that should be targeted for surveillance or management.

  12. Life history diversity of Snake River finespotted cutthroat trout: managing for persistence in a rapidly changing environment

    USGS Publications Warehouse

    Homel, Kristen M.; Gresswell, Robert E.; Kershner, Jeffrey L.

    2015-01-01

    Over the last century, native trout have experienced dramatic population declines, particularly in larger river systems where habitats associated with different spawning life history forms have been lost through habitat degradation and fragmentation. The resulting decrease in life history diversity has affected the capacity of populations to respond to environmental variability and disturbance. Unfortunately, because few large rivers are intact enough to permit full expression of life history diversity, it is unclear what patterns of diversity should be a conservation target. In this study, radiotelemetry was used to identify spawning and migration patterns of Snake River Finespotted Cutthroat Trout Oncorhynchus clarkii behnkei in the upper Snake River. Individuals were implanted with radio tags in October 2007 and 2008, and monitored through October 2009. Radio-tagged cutthroat trout in the upper Snake River exhibited variation in spawning habitat type and location, migration distance, spawn timing, postspawning behavior, and susceptibility to mortality sources. Between May and July, Cutthroat Trout spawned in runoff-dominated tributaries, groundwater-dominated spring creeks, and side channels of the Snake River. Individuals migrated up to 101 km from tagging locations in the upper Snake River to access spawning habitats, indicating that the upper Snake River provided seasonal habitat for spawners originating throughout the watershed. Postspawning behavior also varied; by August each year, 28% of spring-creek spawners remained in their spawning location, compared with 0% of side-channel spawners and 7% of tributary spawners. These spawning and migration patterns reflect the connectivity, habitat diversity, and dynamic template of the Snake River. Ultimately, promoting life history diversity through restoration of complex habitats may provide the most opportunities for cutthroat trout persistence in an environment likely to experience increased variability from

  13. Life history of lake herring of Green Bay, Lake Michigan

    USGS Publications Warehouse

    Smith, Stanford H.

    1956-01-01

    Although the lake herring has been an important contributor to the commercial fish production of Green Bay, little has been known about it. This study is based on field observations and data from about 6,500 lake herring collected over the period 1948 to 1952. Relatively nonselective commercial pound nets were a primary source of material for the study of age and growth. Commercial and experimental gill nets were used to obtain data on gear selectivity and vertical distribution. Scales were employed to investigate age and growth. Age group IV normally dominated commercial catches during the first half of the calendar year and age group III the last half. At these ages the fish averaged about 10.5 inches in length. The season's growth started in May, was most rapid in July, and terminated near the end of October. The sexes grew at the same rate. Selectivity of fishing gear was found to influence the estimation of growth. Geographical and annual differences in growth are shown. Factors that might contribute to discrepancies in calculated growth are evaluated. Possible real and apparent causes of growth compensation are given. The relation between length and weight is shown to vary with sex, season, year, and method of capture. Females were relatively more plentiful in commercial catches in February than in May through December. The percentage of females decreased with increase in age in pound-net catches but increased with age in gill-net samples. Within a year class the percentage of females decreased with increase in age. Most Green Bay lake herring mature during their second or third year of life. They are pelagic spawners with most intensive spawning over shallow areas. Spawning takes place between mid-November and mid-December, and eggs hatch in April and May. Lake herring ovaries contained from 3,500 to 11,200 eggs (averaged 6,375). Progress of spawning by age, sex, and length is given. Lake herring were distributed at all depths in Green Bay in early May, were

  14. Divergent life histories of invasive round gobies (Neogobius melanostomus) in Lake Michigan and its tributaries

    USGS Publications Warehouse

    Kornis, Matthew; Weidel, Brian C.; Vander Zanden, M. Jake

    2016-01-01

    Round gobies (Neogobius melanostomus) have invaded benthic habitats of the Laurentian Great Lakes and connected tributary streams. Although connected, these two systems generally differ in temperature (Great Lakes are typically colder), food availability (Dreissenid mussels are more prevalent in Great Lakes), and system size and openness. Here, we compare round goby life histories from inshore Lake Michigan and adjacent tributary systems—an uncommon case study of life-history differences between connected systems. Tributary round gobies grew much faster (average length-at-age of 122.3 vs. 65.7 mm for Age 2 +  round gobies), appeared to have shorter life spans (maximum observed age of 2 vs. 5) and had lower age-at-50% maturity (1.6 vs. 2.4 years; females only) compared to gobies from Lake Michigan. In addition, tributary gobies had greater fecundity at Ages 1–2 than lake gobies, but had fewer eggs for a given body size prior to the first spawning event of the summer. We were not able to determine the cause of the observed life-history differences. Nonetheless, the observed differences in growth, maturation and longevity were consistent with known effects of water temperature, as well as predictions of life-history theory for animals at invasion fronts exposed to novel environmental conditions. The high degree of phenotypic plasticity in connected populations of this invasive species has implications for our understanding of invasive species impacts in different habitats.

  15. Population Variation in the Life History of a Land Fish, Alticus arnoldorum, and the Effects of Predation and Density

    PubMed Central

    Platt, Edward R. M.; Ord, Terry J.

    2015-01-01

    Life history variation can often reflect differences in age-specific mortality within populations, with the general expectation that reproduction should be shifted away from ages experiencing increased mortality. Investigators of life history in vertebrates frequently focus on the impact of predation, but there is increasing evidence that predation may have unexpected impacts on population density that in turn prompt unexpected changes in life history. There are also other reasons why density might impact life history independently of predation or mortality more generally. We investigated the consequences of predation and density on life history variation among populations of the Pacific leaping blenny, Alticus arnoldorum. This fish from the island of Guam spends its adult life out of the water on rocks in the splash zone, where it is vulnerable to predation and can be expected to be sensitive to changes in population density that impact resource availability. We found populations invested more in reproduction as predation decreased, while growth rate varied primarily in response to population density. These differences in life history among populations are likely plastic given the extensive gene flow among populations revealed by a previous study. The influence of predation and density on life history was unlikely to have operated independently of each other, with predation rate tending to be associated with reduced population densities. Taken together, our results suggest predation and density can have complex influences on life history, and that plastic life history traits could allow populations to persist in new or rapidly changing environments. PMID:26398191

  16. Population Variation in the Life History of a Land Fish, Alticus arnoldorum, and the Effects of Predation and Density.

    PubMed

    Platt, Edward R M; Ord, Terry J

    2015-01-01

    Life history variation can often reflect differences in age-specific mortality within populations, with the general expectation that reproduction should be shifted away from ages experiencing increased mortality. Investigators of life history in vertebrates frequently focus on the impact of predation, but there is increasing evidence that predation may have unexpected impacts on population density that in turn prompt unexpected changes in life history. There are also other reasons why density might impact life history independently of predation or mortality more generally. We investigated the consequences of predation and density on life history variation among populations of the Pacific leaping blenny, Alticus arnoldorum. This fish from the island of Guam spends its adult life out of the water on rocks in the splash zone, where it is vulnerable to predation and can be expected to be sensitive to changes in population density that impact resource availability. We found populations invested more in reproduction as predation decreased, while growth rate varied primarily in response to population density. These differences in life history among populations are likely plastic given the extensive gene flow among populations revealed by a previous study. The influence of predation and density on life history was unlikely to have operated independently of each other, with predation rate tending to be associated with reduced population densities. Taken together, our results suggest predation and density can have complex influences on life history, and that plastic life history traits could allow populations to persist in new or rapidly changing environments.

  17. Variation in cadmium uptake, feeding rate, and life-history effects in the gastropod potamopyrgus antipodarum: linking toxicant effects on individuals to the population level.

    PubMed

    Jensen, A; Forbes, V E; Parker, E D

    2001-11-01

    A life-table response experiment was performed to investigate the effects of sediment-bound cadmium on individual life-history traits and feeding rates of four clones of Potamopyrgus antipodarum. Demographic effects were evaluated using a simple two-stage model to estimate population growth rate (lambda). Decomposition analysis was performed to investigate the contributions of each of the affected life-history traits to the effects observed on lambda, and elasticity analysis was applied to examine the relative sensitivity of lambda to changes in each of the life-history traits. Interclonal differences in tolerance to sediment-bound cadmium were statistically significant but were within an order of magnitude. There were no consistent patterns among clones in terms of which individual life-history trait was most or least sensitive to cadmium exposure. The relative performance of clones did not rank consistently across the cadmium gradient and was dependent on which trait was measured. Although lambda was most sensitive to changes in survival terms, the effects of cadmium on time to first reproduction and reproductive output were the major causes of reductions in lambda. Large percent reductions in some of the individual life-history traits were attenuated at the population level, but very small effects on population growth rate were statistically significant.

  18. Mind Invasion: Situated Affectivity and the Corporate Life Hack.

    PubMed

    Slaby, Jan

    2016-01-01

    In view of the philosophical problems that vex the debate on situated affectivity, it can seem wise to focus on simple cases. Accordingly, theorists often single out scenarios in which an individual employs a device in order to enhance their emotional experience, or to achieve new kinds of experience altogether, such as playing an instrument, going to the movies, or sporting a fancy handbag. I argue that this narrow focus on cases that fit a "user/resource model" tends to channel attention away from more complex and also more problematic instances of situated affectivity. Among these are scenarios in which a social domain draws individuals into certain modes of affective interaction, often by way of attunement and habituation to affective styles and interaction patterns that are normative in the domain in question. This can lead to a phenomenon that is not so much "mind extension" than "mind invasion": affectivity is dynamically framed and modulated from without, often contrary to the prior orientations of the individuals in question. As an example, I discuss affective patterns prevalent in today's corporate workplace. I claim that workplace affect sometimes contributes to what is effectively a "hack" of employees' subjectivity.

  19. Mind Invasion: Situated Affectivity and the Corporate Life Hack

    PubMed Central

    Slaby, Jan

    2016-01-01

    In view of the philosophical problems that vex the debate on situated affectivity, it can seem wise to focus on simple cases. Accordingly, theorists often single out scenarios in which an individual employs a device in order to enhance their emotional experience, or to achieve new kinds of experience altogether, such as playing an instrument, going to the movies, or sporting a fancy handbag. I argue that this narrow focus on cases that fit a “user/resource model” tends to channel attention away from more complex and also more problematic instances of situated affectivity. Among these are scenarios in which a social domain draws individuals into certain modes of affective interaction, often by way of attunement and habituation to affective styles and interaction patterns that are normative in the domain in question. This can lead to a phenomenon that is not so much “mind extension” than “mind invasion”: affectivity is dynamically framed and modulated from without, often contrary to the prior orientations of the individuals in question. As an example, I discuss affective patterns prevalent in today's corporate workplace. I claim that workplace affect sometimes contributes to what is effectively a “hack” of employees' subjectivity. PMID:26941705

  20. Commitment and endurance: common themes in the life histories of civil rights workers who stayed.

    PubMed

    Beardslee, W R

    1983-01-01

    First-person life histories of a group of civil rights workers who have maintained a long-term commitment to the Movement are summarized and analyzed. The importance of relationships with others, changes in the ways the workers viewed themselves, the development of faith in their work, and the reconciliation of their Movement experiences with those of their past life emerge as central themes in their accounts.

  1. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (North Atlantic). American lobster. [Homarus americanus

    SciTech Connect

    MacKenzie, C.; Moring, J.R.

    1985-04-01

    This species profile is a literature summary of the taxonomy, morphology, distribution, life history, and environmental requirements of the American lobster (Homarus americanus). These species profiles are designed to assist in the preparation of environmental impact assessments. The American lobster is a valuable commercial shellfish. After spawning, lobsters undergo a series of molts; as adults they live in coastal and offshore waters. Lobsters are captured in baited traps and incidentally in trawls. About 5 to 6 million pounds were captured commercially in 1983, a downward trend from 1971. Major environmental factors affecting reproduction, growth, and survival are water temperature, oxygen concentration, salinity, and substrate. 82 refs., 2 figs., 3 tabs.

  2. Putting μ/g in a new light: plasticity in life history switch points reflects fine-scale adaptive responses.

    PubMed

    Touchon, Justin C; McCoy, Michael W; Landberg, Tobias; Vonesh, James R; Warkentin, Karen M

    2015-08-01

    Life history theory predicts that organisms with complex life cycles should transition between life stages when the ratio of growth rate (g) to risk of mortality (µ) in the current stage falls below that in the subsequent stage. Empirical support for this idea has been mixed. Implicit in both theory and empirical work is that the risk of mortality in the subsequent stage is unknown. However, some embryos and larvae of both vertebrates and invertebrates assess cues of post-transition predation risk and alter the timing of hatching or metamorphosis accordingly. Furthermore, although life history switch points of prey have traditionally been treated as discrete shifts in morphology or habitat, for many organisms they are continuous transitional periods within which the timing of specific developmental and behavioral events can be plastic. We studied red-eyed treefrogs (Agalychnis callidryas), which detect predators of both larvae and metamorphs, to test if plastic changes during the process of metamorphosis could reconcile the mismatch between life history theory and empirical data and if plasticity in an earlier stage transition (hatching) would affect plasticity at a subsequent stage transition (metamorphosis). We reared tadpoles from hatching until metamorphosis in a full-factorial cross of two hatching ages (early- vs. late-hatched) and the presence or absence of free-roaming predators of larvae (giant water bugs) and metamorphs (fishing spiders). Hatching age affected the times from oviposition to tail resorption and from hatching to emergence onto land, but did not alter responses to predators or developmental stage at emergence. Tadpoles did not alter their age at emergence or tail resorption in response to larval or metamorph predators, despite the fact that predators reduced tadpole density by ~30%. However, developmental stage at emergence and time needed to complete metamorphosis in the terrestrial environment were plastic and consistent with predictions

  3. Effects on life history variables and population dynamics following maternal metal exposure in the live-bearing fish Gambusia affinis.

    PubMed

    Cazan, Alfy Morales; Klerks, Paul L

    2015-04-01

    This study investigated the effect of maternal copper and maternal cadmium exposure on life history variables and population dynamics in a live-bearing fish species. Gravid females were exposed to copper, cadmium, or background metal levels (control); maternal transfer of the metals was previously demonstrated using the exact same design. Each female's first brood, born after the exposure, was subdivided into two groups. One group was raised in the laboratory, to assess time-to and size-at sexual maturity, reproductive output and other life history variables. Offspring from the other group were used to start four mesocosm populations for each treatment. These populations were sampled monthly, for about 18 months, to assess population dynamics. For the laboratory-reared fish, offspring of copper-exposed females reached sexual maturity at a smaller size than did offspring from the other treatments. Maternal copper exposure and maternal cadmium exposure both resulted in fewer broods and an increase in gestation time. No impacts were detected for brood size, inter-brood interval, time-to-sexual-maturity, or life span. In the greenhouse population study, no effect of maternal copper or cadmium exposure was evident for population parameters, other than that the relative abundance of juveniles and/or newborns was reduced in populations established with offspring of the exposed females. This study provided evidence that a short-term metal exposure of gravid females can negatively affect their offspring's life history variables and potentially influence population dynamics in a life-bearing fish species.

  4. Characterizing the early life history of an imperiled freshwater mussel (Ptychobranchus jonesi) with host-fish determination and fecundity estimation

    USGS Publications Warehouse

    Mcleod, John; Jelks, Howard; Pursifull, Sandra; Johnson, Nathan A.

    2017-01-01

    Conservation of imperiled species is frequently challenged by insufficient knowledge of life history and environmental factors that affect various life stages. The larvae (glochidia) of most freshwater mussels in the family Unionidae are obligate ectoparasites of fishes. We described the early life history of the federally endangered Southern Kidneyshell Ptychobranchus jonesi and compared methods for estimating fecundity and conducting host trials on this conglutinate-producing mussel species. Glochidial inoculation baths and direct feeding of conglutinates to Percina nigrofasciata, Etheostoma edwini, and Etheostoma fusiforme resulted in successful metamorphosis to the juvenile life stage. Ptychobranchus jonesi glochidia did not metamorphose on 25 other species of fishes tested representing 11 families. Three juveniles were recovered from Gambusia holbrooki resulting in a metamorphosis rate <1%. We characterize P. jonesi as a host-fish specialist that fractionally releases conglutinates from late January to early June. Intact P. jonesi conglutinates resemble simuliid fly larvae attached to an egg-like structure, but most conglutinates were released as segments representing separate egg or larva mimics. Viability of glochidia encased within a conglutinate was >90% for ≥5 d. Feeding conglutinates directly to fishes allowed us to estimate seminatural infestation rates and calculate average numbers of juveniles produced per conglutinate, unlike the traditional approach of infesting fish hosts in an inoculation bath. Regressions based on the physical dimensions of each conglutinate or conglutinate segment were the most practical method used to estimate fecundity. Species distribution information, early life-history description, and methods developed for determining fecundity and conducting host trials may assist in the conservation of P. jonesi during recovery options that include captive propagation, augmentation, and reestablishment.

  5. Does Death Anxiety Affect End-of-Life Care Discussions?

    PubMed Central

    Brown, Alaina J.; Shen, Megan J.; Ramondetta, Lois M.; Bodurka, Diane C.; Giuntoli, Robert L.; Diaz-Montes, Teresa

    2017-01-01

    Objectives The aim of this study was to determine if a gynecologic cancer patient's comfort level discussing end-of-life care issues with her caregivers is related to her death anxiety level. Materials/Methods Gynecologic oncology clinic patients were asked to rate their degree of agreeability with 4 statements regarding comfort level discussing end-of-life care issues. Participants also completed the Hoge's Intrinsic Religiosity Scale and Templer's Death Anxiety Scale. Results Four hundred one surveys were distributed. One hundred twenty-nine patients participated, with a response rate of 32.2%. The median age of the sample was 55 years. Most patients were white (72.9%), married (58.9%), and Christian (85.3%). Most patients had ovarian cancer (40.4%). Of the 74 patients who knew their cancer stage, 59% had been diagnosed with advanced (stage III-IV) disease. Thirty-three percent were currently in remission, and 17% had recurrent disease. Of all patients surveyed, 32.6% were currently receiving treatment. Chemotherapy was the most common treatment (62% of those being treated). Higher level of comfort discussing end-of-life care topics such as do-not-resuscitate orders with family members was significantly associated with decreased death anxiety (P = 0.008 and P = 0.001). There was no significant association between comfort level when patients discussed do-not-resuscitate orders with physicians and patients' death anxiety (P = 0.14). After controlling for age, race, marital status, education level, current treatment status, and religiosity, linear regression analysis demonstrated that the relationship between a patient's increased comfort level when discussing end-of-life care topics with family members and decreased death anxiety remained statistically significant (P = 0.005 and P = 0.001). Conclusions Conversations regarding goals of treatment are an important component of caring for cancer patients. Death anxiety may contribute to decreased communication between

  6. Quality of life of 'normal' controls: association with lifetime history of mental illness.

    PubMed

    Schechter, Dianne; Endicott, Jean; Nee, John

    2007-07-30

    This study assessed the perceived quality of life of individuals who were not in treatment for a psychiatric disorder and who were volunteers for a program to recruit control subjects. Subjects completed the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q) and a diagnostic evaluation for lifetime history of mental disorders. Individuals were assigned to one of four categories according to the results of the diagnostic evaluation: Never Mentally Ill (NMI), one episode of a Minor Mental Disorder (MMD), Currently Not Mentally Ill with a serious history of mental illness (CNMI), and Currently Mentally Ill (CMI). Subjects in the two healthiest groups (NMI, MMD) reported the greatest life satisfaction and generally did not differ from each other. Subjects in the CNMI group reported significantly less satisfaction than subjects in the NMI and MMD groups, but greater life satisfaction than subjects who were currently mentally ill (CMI). The results demonstrate that an individual's current quality of life is strongly related to the extent of his or her history of mental illness. The findings provide the first available benchmarks for the Q-LES-Q for the degree of life satisfaction experienced by an untreated sample of individuals.

  7. Landscape attributes and life history variability shape genetic structure of trout populations in a stream network

    USGS Publications Warehouse

    Neville, H.M.; Dunham, J.B.; Peacock, M.M.

    2006-01-01

    Spatial and temporal landscape patterns have long been recognized to influence biological processes, but these processes often operate at scales that are difficult to study by conventional means. Inferences from genetic markers can overcome some of these limitations. We used a landscape genetics approach to test hypotheses concerning landscape processes influencing the demography of Lahontan cutthroat trout in a complex stream network in the Great Basin desert of the western US. Predictions were tested with population- and individual-based analyses of microsatellite DNA variation, reflecting patterns of dispersal, population stability, and local effective population sizes. Complementary genetic inferences suggested samples from migratory corridors housed a mixture of fish from tributaries, as predicted based on assumed migratory life histories in those habitats. Also as predicted, populations presumed to have greater proportions of migratory fish or from physically connected, large, or high quality habitats had higher genetic variability and reduced genetic differentiation from other populations. Populations thought to contain largely non-migratory individuals generally showed the opposite pattern, suggesting behavioral isolation. Estimated effective sizes were small, and we identified significant and severe genetic bottlenecks in several populations that were isolated, recently founded, or that inhabit streams that desiccate frequently. Overall, this work suggested that Lahontan cutthroat trout populations in stream networks are affected by a combination of landscape and metapopulation processes. Results also demonstrated that genetic patterns can reveal unexpected processes, even within a system that is well studied from a conventional ecological perspective. ?? Springer 2006.

  8. Life-History Traits of Macrolophus pygmaeus with Different Prey Foods

    PubMed Central

    Sylla, Serigne; Brévault, Thierry; Diarra, Karamoko; Bearez, Philippe; Desneux, Nicolas

    2016-01-01

    Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a generalist predatory mirid widely used in augmentative biological control of various insect pests in greenhouse tomato production in Europe, including the invasive tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae). However, its biocontrol efficacy often relies on the presence of alternative prey. The present study aimed at evaluating the effect of various prey foods (Ephestia kuehniella eggs, Bemisia tabaci nymphs, Tuta absoluta eggs and Macrosiphum euphorbiae nymphs) on some life history traits of M. pygmaeus. Both nymphal development and adult fertility of M. pygmaeus were significantly affected by prey food type, but not survival. Duration of nymphal stage was higher when M. pygmaeus fed on T. absoluta eggs compared to the other prey. Mean fertility of M. pygmaeus females was greatest when fed with B. tabaci nymphs, and was greater when offered M. euphorbiae aphids and E. kuehniella eggs than when offered T. absoluta eggs. Given the low quality of T. absoluta eggs, the efficacy of M. pygmaeus to control T. absoluta may be limited in the absence of other food sources. Experiments for assessing effectiveness of generalist predators should involve the possible impact of prey preference as well as a possible prey switching. PMID:27870857

  9. Rhodnius prolixus Life History Outcomes Differ when Infected with Different Trypanosoma cruzi I Strains

    PubMed Central

    Peterson, Jennifer K.; Graham, Andrea L.; Dobson, Andrew P.; Chávez, Omar Triana

    2015-01-01

    The effect of a parasite on the life history of its vector is important for understanding and predicting disease transmission. Chagas disease agent Trypanosoma cruzi is a generalist parasite that is diverse across scales from its genetic diversity to the 100s of mammal and vector species it infects. Its vertebrate hosts show quite variable responses to infection, however, to date there are no studies looking at how T. cruzi variability might result in variable outcomes in its invertebrate host. Therefore, we investigated the effect of different T. cruzi I strains on Rhodnius prolixus survival and development. We found significant variation between insects infected with different strains, with some strains having no effect, as compared with uninfected insects, and others with significantly lower survival and development. We also found that different variables had varying importance between strains, with the effect of time postinfection and the blood:weight ratio of the infective meal significantly affecting the survival of insects infected with some strains, but not others. Our results suggest that T. cruzi can be pathogenic not only to its vertebrate hosts but also to its invertebrate hosts. PMID:26078316

  10. The importance of habitat and life history to extinction risk in sharks, skates, rays and chimaeras

    PubMed Central

    García, Verónica B; Lucifora, Luis O; Myers, Ransom A

    2007-01-01

    We compared life-history traits and extinction risk of chondrichthyans (sharks, rays and chimaeras), a group of high conservation concern, from the three major marine habitats (continental shelves, open ocean and deep sea), controlling for phylogenetic correlation. Deep-water chondrichthyans had a higher age at maturity and longevity, and a lower growth completion rate than shallow-water species. The average fishing mortality needed to drive a deep-water chondrichthyan species to extinction (Fextinct) was 38–58% of that estimated for oceanic and continental shelf species, respectively. Mean values of Fextinct were 0.149, 0.250 and 0.368 for deep-water, oceanic and continental shelf species, respectively. Reproductive mode was an important determinant of extinction risk, while body size had a weak effect on extinction risk. As extinction risk was highly correlated with phylogeny, the loss of species will be accompanied by a loss of phylogenetic diversity. Conservation priority should not be restricted to large species, as is usually suggested, since many small species, like those inhabiting the deep ocean, are also highly vulnerable to extinction. Fishing mortality of deep-water chondrichthyans already exploited should be minimized, and new deep-water fisheries affecting chondrichthyans should be prevented. PMID:17956843

  11. Linking life-history traits, ecology, and niche breadth evolution in North American eriogonoids (Polygonaceae).

    PubMed

    Kostikova, Anna; Litsios, Glenn; Salamin, Nicolas; Pearman, Peter B

    2013-12-01

    Macroevolutionary and microevolutionary studies provide complementary explanations of the processes shaping the evolution of niche breadth. Macroevolutionary approaches scrutinize factors such as the temporal and spatial environmental heterogeneities that drive differentiation among species. Microevolutionary studies, in contrast, focus on the processes that affect intraspecific variability. We combine these perspectives by using macroevolutionary models in a comparative study of intraspecific variability. We address potential differences in rates of evolution of niche breadth and position in annual and perennial plants of the Eriogonoideae subfamily of the Polygonaceae. We anticipated higher rates of evolution in annuals than in perennials owing to differences in generation time that are paralleled by rates of molecular evolution. Instead, we found that perennial eriogonoid species present greater environmental tolerance (wider climate niche) than annual species. Niche breadth of perennial species has evolved two to four times faster than in annuals, while niche optimum has diversified more rapidly among annual species than among perennials. Niche breadth and average elevation of species are correlated. Moreover, niche breadth increases more rapidly with mean species elevation in perennials than in annuals. Our results suggest that both environmental gradients and life-history strategy influence rates and patterns of niche breadth evolution.

  12. Life history plasticity magnifies the ecological effects of a social wasp invasion

    PubMed Central

    Wilson, Erin E.; Mullen, Lynne M.; Holway, David A.

    2009-01-01

    An unresolved question in ecology concerns why the ecological effects of invasions vary in magnitude. Many introduced species fail to interact strongly with the recipient biota, whereas others profoundly disrupt the ecosystems they invade through predation, competition, and other mechanisms. In the context of ecological impacts, research on biological invasions seldom considers phenotypic or microevolutionary changes that occur following introduction. Here, we show how plasticity in key life history traits (colony size and longevity), together with omnivory, magnifies the predatory impacts of an invasive social wasp (Vespula pensylvanica) on a largely endemic arthropod fauna in Hawaii. Using a combination of molecular, experimental, and behavioral approaches, we demonstrate (i) that yellowjackets consume an astonishing diversity of arthropod resources and depress prey populations in invaded Hawaiian ecosystems and (ii) that their impact as predators in this region increases when they shift from small annual colonies to large perennial colonies. Such trait plasticity may influence invasion success and the degree of disruption that invaded ecosystems experience. Moreover, postintroduction phenotypic changes may help invaders to compensate for reductions in adaptive potential resulting from founder events and small population sizes. The dynamic nature of biological invasions necessitates a more quantitative understanding of how postintroduction changes in invader traits affect invasion processes. PMID:19625616

  13. Effects of selected fertilizers on the life history of Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B.

    PubMed

    England, K M; Sadof, C S; Cañnas, L A; Kuniyoshi, C H; Lopez, R G

    2011-04-01

    We tested the effects among a purportedly sustainable water-soluble fertilizer, a conventional water-soluble fertilizer, an alternation of these, a controlled-release fertilizer, and a clear water control on the life-history traits of sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae; =Bemisia argentifolii Bellows & Perring) biotype B reared on poinsettia (Euphorbia pulcherrima Willdenow ex Klotzch). Free amino acids in petioles were measured to estimate plant nutrient assimilation and phloem nutritional quality for B. tabaci biotype B. The sustainable fertilizer produced plants with the highest concentration of amino acids. In contrast, fecundity of whiteflies was lowest in plants treated with the sustainable fertilizer and the water control. The relationship between total amino acids in phloem and survival was significantly quadratic, with the highest survival at intermediate levels. Fecundity, however, was negatively correlated with total amino acid content of the maternal host plant. Variation in total amino acid concentration in petioles of plants treated within fertilizer treatments makes it difficult to predict whether a particular fertilizer will produce plants with enough amino acids to deleteriously affect both survivorship and fecundity and yet yield a plant of good quality. Despite this limitation, we can conclude that the use of this sustainable fertilizer will not cause increases in whitefly populations relative to plants fertilized with water-soluble and slow-release fertilizers that deliver the same level of nitrogen to the plant.

  14. Life History Variation in Invading Applesnails (Pomacea canaliculata) May Pose Ecological Threats to Wetlands

    NASA Astrophysics Data System (ADS)

    Marfurt, R. K.; Boland, B. B.; Burks, R. L.

    2005-05-01

    In native habitats, channeled applesnails (Pomacea canaliculata) graze periphyton. However, casual observations from introduced populations suggest these invaders show variation in feeding ecology, predator response and life history strategies. Attempts to predict this consumer influence on ecosystem function suffer from a lack of basic data. We tested how salinity affected snail mortality. Both adults and hatchlings tolerated salinity levels up to 8 ppt. Adult feeding on lettuce increased significantly at 8 ppt compared to 0 ppt (p = 0.002), while hatchling consumption of algae did not vary (p = 0.284). To see how these consumers responded to predators from the invaded ecosystem, we tested behavioural responses to predatory cues from fish, turtles, crayfish and adult applesnails. Results indicated that fish and crayfish prompted similar predator-avoidance behaviors in hatchlings (p's < 0.05) and that hatchling response changed over time. Consumption rates of juvenile redear sunfish did not vary (x2, p > 0.05) between native (ramshorn) and exotic applesnails, whereas adult fish consumed more applesnails (x2, p < 0.001). Our current efforts focus on examining if predator presence or macrophyte choice alters applesnail feeding rates. Research providing insight into the basic ecology of applesnails can foster management efforts at the ecosystem scale.

  15. Living under stressful conditions: Fish life history strategies across environmental gradients in estuaries

    NASA Astrophysics Data System (ADS)

    Teichert, Nils; Pasquaud, Stéphanie; Borja, Angel; Chust, Guillem; Uriarte, Ainhize; Lepage, Mario

    2017-03-01

    The life history strategies of fishes can be defined by specific combinations of demographic traits that influence species performances depending on environmental features. Hence, the constraints imposed by the local conditions restrict the range of successful strategies by excluding species poorly adapted. In the present study, we compared the demographic strategies of fish caught in 47 estuaries of the North East Atlantic coast, aiming to determine the specific attributes of resident species and test for changes in trait associations along the environmental gradients. Eight demographic traits were considered to project our findings within a conceptual triangular model, composed on three endpoint strategies: (i) periodic (large size, long generation time, high fecundity); (ii) opportunistic (small size, short generation time, high reproductive effort); and (iii) equilibrium (low fecundity, large egg size, parental care). We demonstrated that various life history strategies co-exist in estuaries, but equilibrium species were scarce and restricted to euhaline open-water. Resident species form a specialised assemblage adapted to high spatiotemporal variability of estuarine conditions, i.e. opportunistic attributes associated with parental care. Even with these singular attributes, our findings revealed changes in distribution of resident species across the estuarine gradients linked to their life history traits. Among other patterns, the diversity of life history strategies significantly decreased from euhaline to oligohaline areas and along gradient of human disturbances. These trends were associated with a convergence of species traits toward short generation times, suggesting that long-lived species with late maturation are more severely impacted by disturbance and environmental stress.

  16. Life history factors, personality and the social clustering of sexual experience in adolescents

    PubMed Central

    2016-01-01

    Adolescent sexual behaviour may show clustering in neighbourhoods, schools and friendship networks. This study aims to assess how experience with sexual intercourse clusters across the social world of adolescents and whether predictors implicated by life history theory or personality traits can account for its between-individual variation and social patterning. Using data on 2877 adolescents from the Avon Longitudinal Study of Parents and Children, we ran logistic multiple classification models to assess the clustering of sexual experience by approximately 17.5 years in schools, neighbourhoods and friendship networks. We examined how much clustering at particular levels could be accounted for by life history predictors and Big Five personality factors. Sexual experience exhibited substantial clustering in friendship networks, while clustering at the level of schools and neighbourhoods was minimal, suggesting a limited role for socio-ecological influences at those levels. While life history predictors did account for some variation in sexual experience, they did not explain clustering in friendship networks. Personality, especially extraversion, explained about a quarter of friends' similarity. After accounting for life history factors and personality, substantial unexplained similarity among friends remained, which may reflect a tendency to associate with similar individuals or the social transmission of behavioural norms. PMID:27853543

  17. Timing of Pubertal Maturation in Girls: An Integrated Life History Approach

    ERIC Educational Resources Information Center

    Ellis, Bruce J.

    2004-01-01

    Life history theory provides a metatheoretical framework for the study of pubertal timing from an evolutionary-developmental perspective. The current article reviews 5 middle-level theories-energetics theory, stress-suppression theory, psychosocial acceleration theory, paternal investment theory, and child development theory-each of which applies…

  18. COPEPOD REPRODUCTIVE STRATEGIES: LIFE-HISTORY THEORY, PHYLOGENETIC PATTERN AND INVASION OF INLAND WATERS. (R824771)

    EPA Science Inventory

    Abstract

    Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven ...

  19. Life History and Damage of a new Baradinae Weevil (Coleoptera: Curculionidae) on Amaryllis.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A small Baradinae weevil that feeds on amaryllis plants has been known in Florida for over fifteen years. It is yet to be named taxonomically and its life history has not been studied previously. Observations on weevil damage were made on containerized amaryllis (Hippeastrum hybrids) plants naturall...

  20. Life History Methodologies: An Investigation into Work-Based Learning Experiences of Community Education Workers

    ERIC Educational Resources Information Center

    Issler, Sally; Nixon, David

    2007-01-01

    This article focuses on an investigation into the learning journeys undertaken by managers of a community education project in an area of urban deprivation. A constructivist interpretation of life history narrative revealed the positive effects of community workers' heavy dependence on experiential work-based learning, which resulted in the…

  1. Life-history organization of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) in Yellowstone Lake

    USGS Publications Warehouse

    Gresswell, Robert E.; Liss, W.J.; Larson, Gary L.

    1994-01-01

    Life-history organization of the cutthroat trout (Oncorhynchus clarki) may be viewed at various levels, including species, subspecies, metapopulation, population, or individual. Each level varies in spatial scale and temporal persistence, and components at each level continually change with changes in environment. Cutthroat trout are widely distributed throughout the western United States, occurring in such diverse environments as coastal rivers of the Pacific Northwest and interior streams of the Great Basin. During its evolution the species has organized into 14 subspecies with many different life-history characteristics and habitat requirements. Within subspecies, organization is equally complex. For example, life-history traits, such as average size and age, migration strategy, and migration timing, vary among individual spawning populations of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) in tributary streams of Yellowstone Lake. Understanding the effects of human perturbations on life-history organization is critical for management of the cutthroat trout and other polytypic salmonid species. Loss of diversity at any hierarchical level jeopardizes the long-term ability of the species to adapt to changing environments, and it may also lead to increased fluctuations in abundance and yield and increase the risk of extinction.

  2. Larval life history responses to food deprivation in three species of predatory lady beetles (Coleoptera: Coccinellidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We studied life history responses of larvae of three coccinellid species, Coleomegilla maculata (DeGeer), Hippodamia convergens Guerin-Meneville, and Harmonia axyridis (Pallas), when deprived of food for different periods of time during the fourth stadium. The coccinellid species did not differ in ...

  3. Intersections of Life Histories and Science Identities: The Stories of Three Preservice Elementary Teachers

    ERIC Educational Resources Information Center

    Avraamidou, Lucy

    2016-01-01

    Grounded within Connelly and Clandinin's conceptualization of teachers' professional identity in terms of "stories to live by" and through a life-history lens, this multiple case study aimed to respond to the following questions: (a) How do three preservice elementary teachers view themselves as future science teachers? (b) How have the…

  4. Gambling for Capital: Learning Disability, Inclusive Research and Collaborative Life Histories

    ERIC Educational Resources Information Center

    Bjornsdottir, Kristin; Svensdottir, Aileen Soffia

    2008-01-01

    The aim of this paper is to reflect on research collaboration between a research participant with learning disability and a nondisabled doctoral student. In the paper we explore the inclusiveness of our research partnership and how collaborative life histories can be empowering both for participants and researchers. We suggest that it is possible…

  5. The "Battlefield": Life Histories of Two Higher Education Staff Members of Color

    ERIC Educational Resources Information Center

    Gomez, Mary Louise; Ocasio, Kelly; Lachuk, Amy Johnson; Powell, Shameka N.

    2015-01-01

    Deploying Russian philosopher M. M. Bakhtin's notions of utterances or communicative interactions, we explore the life histories of two administrators at State University, a predominantly White institution of higher education in the Midwestern United States. In particular, we explore how working with White students, peers, and supervisors demands…

  6. The Ecology, Life History, and Phylogeny of the Marine Thecate Heterotrophic Dinoflagellates Protoperidinium and Diplopsalidaceae (Dinophyceae)

    DTIC Science & Technology

    2006-09-01

    Materials and Methods 29 Results 32 Discussion 85 References 94 Chapter 3. Sexual and asexual reproduction in Protoperidinium steidingerae Balech...strategies (Pfiester and Anderson 1987). Reproduction of haploid swimming cells is generally by asexual division. In times of environmental or...description of the life history of any Protoperidinium species, including both sexual and asexual reproduction . In chapter 4, I explored the molecular

  7. The Juvenile Transition: A Developmental Switch Point in Human Life History

    ERIC Educational Resources Information Center

    Del Giudice, Marco; Angeleri, Romina; Manera, Valeria

    2009-01-01

    This paper presents a new perspective on the transition from early to middle childhood (i.e., human juvenility), investigated in an integrative evolutionary framework. Juvenility is a crucial life history stage, when social learning and interaction with peers become central developmental functions; here it is argued that the "juvenile transition"…

  8. APPLICATION OF PERTURBATION SIMULATIONS IN POPULATION RISK ASSESSMENT FOR DIFFERENT LIFE HISTORY STRATEGIES AND ELASTICITY PATTERNS

    EPA Science Inventory

    Population structure and life history strategies are determinants of how populations respond to stressor-induced impairments in organism-level responses, but a consistent and holistic analysis has not been reported. Effects on population growth rate were modeled using seven theor...

  9. Breathing Life into History: Using Role-Playing to Engage Students

    ERIC Educational Resources Information Center

    Cruz, Barbara C.; Murthy, Shalini A.

    2006-01-01

    Alternately referred to as historical role-playing, dramatic improvisation, sociodrama, or first-person characterization, role playing is a teaching strategy that often uses official accounts, personal narratives, and diaries to recreate a particular time period, specific event, or breathe life into a character from history. Historical…

  10. Evolutionary Functions of Social Play: Life Histories, Sex Differences, and Emotion Regulation

    ERIC Educational Resources Information Center

    LaFreniere, Peter

    2011-01-01

    Many research findings about animal play apply to children's play, revealing structural and functional similarities with mammals in general and primates in particular. After an introduction to life-history theory, and before turning to humans, the author reviews research about the two mammals in which play has been studied the most extensively:…

  11. Comparing life history characteristics of Lake Michigan’s naturalized and stocked Chinook Salmon

    USGS Publications Warehouse

    Kerns, Janice A; Rogers, Mark W.; Bunnell, David; Claramunt, Randall M.; Collingsworth, Paris D.

    2016-01-01

    Lake Michigan supports popular fisheries for Chinook Salmon Oncorhynchus tshawytscha that have been sustained by stocking since the late 1960s. Natural recruitment of Chinook Salmon in Lake Michigan has increased in the past few decades and currently contributes more than 50% of Chinook Salmon recruits. We hypothesized that selective forces differ for naturalized populations born in the wild and hatchery populations, resulting in divergent life history characteristics with implications for Chinook Salmon population production and the Lake Michigan fishery. First, we conducted a historical analysis to determine if life history characteristics changed through time as the Chinook Salmon population became increasingly naturalized. Next, we conducted a 2-year field study of naturalized and hatchery stocked Chinook Salmon spawning populations to quantify differences in fecundity, egg size, timing of spawning, and size at maturity. In general, our results did not indicate significant life history divergence between naturalized and hatchery-stocked Chinook Salmon populations in Lake Michigan. Although historical changes in adult sex ratio were correlated with the proportion of naturalized individuals, changes in weight at maturity were better explained by density-dependent factors. The field study revealed no divergence in fecundity, timing of spawning, or size at maturity, and only small differences in egg size (hatchery > naturalized). For the near future, our results suggest that the limited life history differences observed between Chinook Salmon of naturalized and hatchery origin will not lead to large differences in characteristics important to the dynamics of the population or fishery.

  12. Bacterial associations across house fly life history: Evidence for trans-stadial carriage from managed manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    House flies (Diptera: Muscidae; Musca domestica L.) associate with microbe-rich substrates throughout life history. Since larvae utilize bacteria as a food source, most taxa present in the larval substrate, e.g. manure, are digested or degraded. However, some species survive and are present as third...

  13. Stories of Learning across the Lifespan: Life History and Biographical Research in Adult Education

    ERIC Educational Resources Information Center

    Gouthro, Patricia

    2014-01-01

    Life history or biographical approaches to research in lifelong learning may be particularly useful for researchers working from a social purpose and/or feminist perspective. Adult educators working from an emancipatory framework are often curious about factors that shape people's lives, both from an individualistic, biographical perspective and…

  14. Beyond Cumulative Risk: Distinguishing Harshness and Unpredictability as Determinants of Parenting and Early Life History Strategy

    ERIC Educational Resources Information Center

    Belsky, Jay; Schlomer, Gabriel L.; Ellis, Bruce J.

    2012-01-01

    Drawing on life history theory, Ellis and associates' (2009) recent across- and within-species analysis of ecological effects on reproductive development highlighted two fundamental dimensions of environmental variation and influence: harshness and unpredictability. To evaluate the unique contributions of these factors, the authors of present…

  15. Reevaluating geographic variation in life-history traits of a widespread Nearctic amphibian

    USGS Publications Warehouse

    Davenport, Jon M.; Hossack, Blake R.

    2016-01-01

    Animals from cold environments are usually larger than animals from warm environments, which often produce clines in body size. Because variation in body size can lead to trade-offs between growth and reproduction, life-history traits should also vary across climatic gradients. To determine if life-history traits of wood frogs Rana sylvatica vary with climate, we examined female and male body length, clutch size, and ovum size from 37 locations across an unprecedented 32° of latitude. In conflict with recent research, body size, and ovum size decreased in cold climates and at higher latitudes. Clutch size did not vary with climate or latitude, but reproductive effort (clutch size:female size) did, suggesting selection for a life-history traits that favors maximizing propagule number over propagule size in cold climates. With accelerating climate change that will expose populations to novel environmental conditions, it is important to identify the limits of adaptation, which can be informed by greater understanding of variation in life-history traits.

  16. Unrestricted migration favours virulent pathogens in experimental metapopulations: evolutionary genetics of a rapacious life history.

    PubMed

    Eshelman, Christal M; Vouk, Roxanne; Stewart, Jodi L; Halsne, Elizabeth; Lindsey, Haley A; Schneider, Stacy; Gualu, Miliyard; Dean, Antony M; Kerr, Benjamin

    2010-08-27

    Understanding pathogen infectivity and virulence requires combining insights from epidemiology, ecology, evolution and genetics. Although theoretical work in these fields has identified population structure as important for pathogen life-history evolution, experimental tests are scarce. Here, we explore the impact of population structure on life-history evolution in phage T4, a viral pathogen of Escherichia coli. The host-pathogen system is propagated as a metapopulation in which migration between subpopulations is either spatially restricted or unrestricted. Restricted migration favours pathogens with low infectivity and low virulence. Unrestricted migration favours pathogens that enter and exit their hosts quickly, although they are less productive owing to rapid extirpation of the host population. The rise of such 'rapacious' phage produces a 'tragedy of the commons', in which better competitors lower productivity. We have now identified a genetic basis for a rapacious life history. Mutations at a single locus (rI) cause increased virulence and are sufficient to account for a negative relationship between phage competitive ability and productivity. A higher frequency of rI mutants under unrestricted migration signifies the evolution of rapaciousness in this treatment. Conversely, spatially restricted migration favours a more 'prudent' pathogen strategy, in which the tragedy of the commons is averted. As our results illustrate, profound epidemiological and ecological consequences of life-history evolution in a pathogen can have a simple genetic cause.

  17. The Power of Life Histories: Moving Readers to Greater Acts of Empathy through Literature and Memoir

    ERIC Educational Resources Information Center

    Lee, Valarie G.; Madden, Marjorie E.

    2016-01-01

    This paper argues that narratives, specifically literature and memoir, offer a way to build empathy and understanding by moving readers to deeper levels of text interpretation and critique. The paper examines a new literacy framework, Life Histories, that uses talk, collaboration, writing, and performance to understand the complex relationships…

  18. Herbivore-mediated ecological costs of reproduction shape the life history of an iteroparous plant.

    PubMed

    Miller, Tom E X; Tenhumberg, Brigitte; Louda, Svata M

    2008-02-01

    Plant reproduction yields immediate fitness benefits but can be costly in terms of survival, growth, and future fecundity. Life-history theory posits that reproductive strategies are shaped by trade-offs between current and future fitness that result from these direct costs of reproduction. Plant reproduction may also incur indirect ecological costs if it increases susceptibility to herbivores. Yet ecological costs of reproduction have received little empirical attention and remain poorly integrated into life-history theory. Here, we provide evidence for herbivore-mediated ecological costs of reproduction, and we develop theory to examine how these costs influence plant life-history strategies. Field experiments with an iteroparous cactus (Opuntia imbricata) indicated that greater reproductive effort (proportion of meristems allocated to reproduction) led to greater attack by a cactus-feeding insect (Narnia pallidicornis) and that damage by this herbivore reduced reproductive success. A dynamic programming model predicted strongly divergent optimal reproductive strategies when ecological costs were included, compared with when these costs were ignored. Meristem allocation by cacti in the field matched the optimal strategy expected under ecological costs of reproduction. The results indicate that plant reproductive allocation can strongly influence the intensity of interactions with herbivores and that associated ecological costs can play an important selective role in the evolution of plant life histories.

  19. Family Environments, Adrenarche, and Sexual Maturation: A Longitudinal Test of a Life History Model

    ERIC Educational Resources Information Center

    Ellis, Bruce J.; Essex, Marilyn J.

    2007-01-01

    Life history theorists have proposed that humans have evolved to be sensitive to specific features of early childhood environments and that exposure to different environments biases children toward development of different reproductive strategies, including differential pubertal timing. The current research provides a longitudinal test of this…

  20. Real-Life Spatial Skills, Handedness, and Family History of Handedness

    ERIC Educational Resources Information Center

    Ecuyer-Dab, I.; Tremblay, T.; Joanette, Y.; Passini, R.

    2005-01-01

    According to Annett (1985), pronounced left hemisphere lateralization for language abilities in women, as in female absolute right-handers, limits their right hemisphere capacity and spatial abilities. This study examines the degree of handedness and the family history of non-right-handedness with respect to real-life spatial abilities in women.…

  1. Intersections of life histories and science identities: the stories of three preservice elementary teachers

    NASA Astrophysics Data System (ADS)

    Avraamidou, Lucy

    2016-03-01

    Grounded within Connelly and Clandinin's conceptualization of teachers' professional identity in terms of 'stories to live by' and through a life-history lens, this multiple case study aimed to respond to the following questions: (a) How do three preservice elementary teachers view themselves as future science teachers? (b) How have the participants' life histories shaped their science identity trajectories? In order to characterize the participants' formation of science identities over time, various data regarding their life histories in relation to science were collected: science biographies, self-portraits, interviews, reflective journals, lesson plans, and classroom observations. The analysis of the data illustrated how the three participants' identities have been in formation from the early years of their lives and how various events, experiences, and interactions had shaped their identities through time and across contexts. These findings are discussed alongside implications for theory, specifically, identity and life-history intersections, for teacher preparation, and for research related to explorations of beginning elementary teachers' identity trajectories.

  2. Life history differences influence the impacts of drought on two pond-breeding salamanders.

    PubMed

    Anderson, Thomas L; Ousterhout, Brittany H; Peterman, William E; Drake, Dana L; Semlitsch, Raymond D

    2015-10-01

    Drought is a strong density-independent environmental filter that contributes to population regulation and other ecological processes. Not all species respond similarly to drought, and the overall impacts can vary depending on life histories. Such differences can necessitate management strategies that incorporate information on individual species to maximize conservation success. We report the effects of a short-term drought on occupancy and reproductive success of two pond-breeding salamanders that differ in breeding phenology (fall vs. spring breeder) across an active military base landscape in Missouri, USA: We surveyed ~200 ponds for the presence of eggs, larvae, and metamorphs from 2011 to 2013. This period coincided with before, during, and after a severe drought that occurred in 2012. The two species showed contrasting responses to drought, where high reproductive failure (34% of ponds) was observed for the spring breeder during a single drought year. Alternatively, the fall breeder only showed a cumulative 8% failure over two years. The number of breeding ponds available for use in the fall decreased during the drought due to pond drying and/or a lack of re-filling. Estimates of occupancy probability declined for the fall-breeding salamander between 2012 and 2013, whereas occupancy probability estimates of the spring breeder increased post-drought. The presence of fish, hydroperiod, the amount of forest cover surrounding ponds, and canopy cover were all found to affect estimates of occupancy probabilities of each species. Pond clustering (distance to nearest pond and the number of ponds within close proximity), hydroperiod, forest cover, and canopy cover influenced both estimates of colonization and extinction probabilities. Our results show life history variation can be important in determining the relative susceptibility of a species to drought conditions, and that sympatric species experiencing the same environmental conditions can respond differently

  3. Niche partitioning in sympatric Gorilla and Pan from Cameroon: implications for life history strategies and for reconstructing the evolution of hominin life history.

    PubMed

    Macho, Gabriele A; Lee-Thorp, Julia A

    2014-01-01

    Factors influencing the hominoid life histories are poorly understood, and little is known about how ecological conditions modulate the pace of their development. Yet our limited understanding of these interactions underpins life history interpretations in extinct hominins. Here we determined the synchronisation of dental mineralization/eruption with brain size in a 20th century museum collection of sympatric Gorilla gorilla and Pan troglodytes from Central Cameroon. Using δ13C and δ15N of individuals' hair, we assessed whether and how differences in diet and habitat use may have impacted on ape development. The results show that, overall, gorilla hair δ13C and δ15N values are more variable than those of chimpanzees, and that gorillas are consistently lower in δ13C and δ15N compared to chimpanzees. Within a restricted, isotopically-constrained area, gorilla brain development appears delayed relative to dental mineralization/eruption [or dental development is accelerated relative to brains]: only about 87.8% of adult brain size is attained by the time first permanent molars come into occlusion, whereas it is 92.3% in chimpanzees. Even when M1s are already in full functional occlusion, gorilla brains lag behind those of chimpanzee (91% versus 96.4%), relative to tooth development. Both bootstrap analyses and stable isotope results confirm that these results are unlikely due to sampling error. Rather, δ15N values imply that gorillas are not fully weaned (physiologically mature) until well after M1 are in full functional occlusion. In chimpanzees the transition from infant to adult feeding appears (a) more gradual and (b) earlier relative to somatic development. Taken together, the findings are consistent with life history theory that predicts delayed development when non-density dependent mortality is low, i.e. in closed habitats, and with the "risk aversion" hypothesis for frugivorous species as a means to avert starvation. Furthermore, the results highlight

  4. Gene Transfer and the Reconstruction of Life's Early History from Genomic Data

    NASA Astrophysics Data System (ADS)

    Gogarten, J. Peter; Fournier, Gregory; Zhaxybayeva, Olga

    2008-03-01

    The metaphor of the unique and strictly bifurcating tree of life, suggested by Charles Darwin, needs to be replaced (or at least amended) to reflect and include processes that lead to the merging of and communication between independent lines of descent. Gene histories include and reflect processes such as gene transfer, symbioses and lineage fusion. No single molecule can serve as a proxy for the tree of life. Individual gene histories can be reconstructed from the growing molecular databases containing sequence and structural information. With some simplifications these gene histories can be represented by furcating trees; however, merging these gene histories into web-like organismal histories, including the transfer of metabolic pathways and cell biological innovations from now-extinct lineages, has yet to be accomplished. Because of these difficulties in interpreting the record retained in molecular sequences, correlations with biochemical fossils and with the geological record need to be interpreted with caution. Advances to detect and pinpoint transfer events promise to untangle at least a few of the intertwined histories of individual genes within organisms and trace them to the organismal ancestors. Furthermore, analysis of the shape of molecular phylogenetic trees may point towards organismal radiations that might reflect early mass extinction events that occurred on a planetary scale.

  5. Gene Transfer and the Reconstruction of Life's Early History from Genomic Data

    NASA Astrophysics Data System (ADS)

    Gogarten, J. Peter; Fournier, Gregory; Zhaxybayeva, Olga

    The metaphor of the unique and strictly bifurcating tree of life, suggested by Charles Darwin, needs to be replaced (or at least amended) to reflect and include processes that lead to the merging of and communication between independent lines of descent. Gene histories include and reflect processes such as gene transfer, symbioses and lineage fusion. No single molecule can serve as a proxy for the tree of life. Individual gene histories can be reconstructed from the growing molecular databases containing sequence and structural information. With some simplifications these gene histories can be represented by furcating trees; however, merging these gene histories into web-like organismal histories, including the transfer of metabolic pathways and cell biological innovations from now-extinct lineages, has yet to be accomplished. Because of these difficulties in interpreting the record retained in molecular sequences, correlations with biochemical fossils and with the geological record need to be interpreted with caution. Advances to detect and pinpoint transfer events promise to untangle at least a few of the intertwined histories of individual genes within organisms and trace them to the organismal ancestors. Furthermore, analysis of the shape of molecular phylogenetic trees may point towards organismal radiations that might reflect early mass extinction events that occurred on a planetary scale.

  6. Effects of pathogen exposure on life history variation in the gypsy moth (Lymantria dispar)

    PubMed Central

    Páez, David J.; Fleming-Davies, Arietta E.; Dwyer, Greg

    2015-01-01

    Investment in host defenses against pathogens may lead to tradeoffs with host fecundity. When such tradeoffs arise from genetic correlations, rates of phenotypic change by natural selection may be affected. However, genetic correlations between host survival and fecundity are rarely quantified. To understand tradeoffs between immune responses to baculovirus exposure and fecundity in the gypsy moth (Lymantria dispar), we estimated genetic correlations between survival probability and traits related to fecundity, such as pupal weight. In addition, we tested whether different virus isolates have different effects on male and female pupal weight. To estimate genetic correlations, we exposed individuals of known relatedness to a single baculovirus isolate. To then evaluate the effect of virus isolate on pupal weight, we exposed a single gypsy moth strain to 16 baculovirus isolates. We found a negative genetic correlation between survival and pupal weight. In addition, virus exposure caused late-pupating females to be identical in weight to males, whereas unexposed females were 2–3 times as large as unexposed males. Finally, we found that female pupal weight is a quadratic function of host mortality across virus isolates, which is likely due to tradeoffs and compensatory growth processes acting at high and low mortality levels, respectively. Overall, our results suggest that fecundity costs may strongly affect the response to selection for disease resistance. In nature, baculoviruses contribute to the regulation of gypsy moth outbreaks, as pathogens often do in forest-defoliating insects. We therefore argue that tradeoffs between host life-history traits may help explain outbreak dynamics. PMID:26201381

  7. The effect of temperature on life history traits of Culex mosquitoes.

    PubMed

    Ciota, Alexander T; Matacchiero, Amy C; Kilpatrick, A Marm; Kramer, Laura D

    2014-01-01

    Climatic changes forecasted in the coming years are likely to result in substantial alterations to the distributions and populations of vectors of arthropod-borne pathogens. Characterization of the effect of temperature shifts on the life history traits of specific vectors is needed to more accurately define how such changes could impact the epidemiological patterns of vector-borne disease. Here, we determined the effect of temperatures including 16, 20, 24, 28, and 32 degreeC on development time, immature survival, adult survival, mosquito size, blood feeding, and fecundity of both field and colonized populations of the Culex mosquitoes Culex pipiens L, Culex quinquefasciatus Say, and Culex restuans Theobald. Our results demonstrate that temperature significantly affects all of these traits, yet also that the extent of this effect is at times incongruent among temperatures, as well as being population and species-specific. Comparisons of colonized mosquitoes with field populations generally demonstrate decreased adult and immature survival, increased blood feeding and egg production, and significant variation in the effects of temperature, indicating that such colonies are not fully representative of natural populations. Results with field populations in general indicate that increases in temperature are likely to accelerate mosquito development, and that this effect is greater at temperatures below 24 degreeC, but also that temperature significantly increases mortality. Among field populations, Cx. restuans were most affected by temperature increases, with decreased longevity relative to other species and significant increases in adult and immature mortality measured with each incremental temperature increase. Despite the unique climates characteristic of the geographic ranges ofCx. quinquefasciatus and Cx. pipiens, evidence of significant species-specific adaptation to temperature ranges was not seen. Taken together, these results indicate that geographic region

  8. Modeling the impacts of life-history traits, canopy gaps, and establishment location on woodland shrub invasions.

    PubMed

    Iannone, Basil V; Zellner, Moira L; Wise, David H

    2014-04-01

    We used an individual-based model to identify how localized patterns of woodland invasions by exotic shrubs are likely influenced by (1) observed variation in age at first reproduction and fecundity, (2) hypothesized effects of canopy gaps on these life-history traits and dispersal, and (3) initial establishment location. Rates of spread accelerated nearly twofold as age at first reproduction decreased from eight to three years or fecundity increased from 3 to 20 offspring per year, illustrating the need to better understand the factors that influence these life-history traits. Canopy gaps facilitated spread by influencing these life-history traits, but not through their effects on dispersal. Invasions starting at the woodland center spread more rapidly than do those starting along the woodland edge. These findings suggest that managers should not only prioritize the removal of shrubs that reproduce the earliest or produce the most offspring, but they should also focus on the invasions in woodlands with high canopy openness and/or that are located in woodland interiors. Investigated factors also affected other invasion characteristics, often in surprising ways. For example, those changes in age at first reproduction and fecundity that increased the rate of spread produced nonparallel patterns of change in the proportions of invasion reproducing, whether or not invasions exhibited clumped or scattered spatial arrangements, and invasional lag. Additionally, canopy gaps influenced these characteristics by increasing fecundity, but not by decreasing age at first reproduction or altering dispersal, suggesting that canopy gaps affect local patterns of exotic-shrub invasions primarily through their positive effects on fruit production.

  9. Diagnosing the dangerous demography of manta rays using life history theory

    PubMed Central

    Pardo, Sebastián A.; Simpfendorfer, Colin A.; Carlson, John K.

    2014-01-01

    Background. The directed harvest and global trade in the gill plates of mantas, and devil rays, has led to increased fishing pressure and steep population declines in some locations. The slow life history, particularly of the manta rays, is cited as a key reason why such species have little capacity to withstand directed fisheries. Here, we place their life history and demography within the context of other sharks and rays. Methods. Despite the limited availability of data, we use life history theory and comparative analysis to estimate the intrinsic risk of extinction (as indexed by the maximum intrinsic rate of population increase rmax) for a typical generic manta ray using a variant of the classic Euler–Lotka demographic model. This model requires only three traits to calculate the maximum intrinsic population growth rate rmax: von Bertalanffy growth rate, annual pup production and age at maturity. To account for the uncertainty in life history parameters, we created plausible parameter ranges and propagate these uncertainties through the model to calculate a distribution of the plausible range of rmax values. Results. The maximum population growth rate rmax of manta ray is most sensitive to the length of the reproductive cycle, and the median rmax of 0.116 year−1 95th percentile [0.089–0.139] is one of the lowest known of the 106 sharks and rays for which we have comparable demographic information. Discussion. In common with other unprotected, unmanaged, high-value large-bodied sharks and rays the combination of very low population growth rates of manta rays, combined with the high value of their gill rakers and the international nature of trade, is highly likely to lead to rapid depletion and potential local extinction unless a rapid conservation management response occurs worldwide. Furthermore, we show that it is possible to derive important insights into the demography extinction risk of data-poor species using well-established life history theory

  10. Diagnosing the dangerous demography of manta rays using life history theory.

    PubMed

    Dulvy, Nicholas K; Pardo, Sebastián A; Simpfendorfer, Colin A; Carlson, John K

    2014-01-01

    Background. The directed harvest and global trade in the gill plates of mantas, and devil rays, has led to increased fishing pressure and steep population declines in some locations. The slow life history, particularly of the manta rays, is cited as a key reason why such species have little capacity to withstand directed fisheries. Here, we place their life history and demography within the context of other sharks and rays. Methods. Despite the limited availability of data, we use life history theory and comparative analysis to estimate the intrinsic risk of extinction (as indexed by the maximum intrinsic rate of population increase r max) for a typical generic manta ray using a variant of the classic Euler-Lotka demographic model. This model requires only three traits to calculate the maximum intrinsic population growth rate r max: von Bertalanffy growth rate, annual pup production and age at maturity. To account for the uncertainty in life history parameters, we created plausible parameter ranges and propagate these uncertainties through the model to calculate a distribution of the plausible range of r max values. Results. The maximum population growth rate r max of manta ray is most sensitive to the length of the reproductive cycle, and the median r max of 0.116 year(-1) 95th percentile [0.089-0.139] is one of the lowest known of the 106 sharks and rays for which we have comparable demographic information. Discussion. In common with other unprotected, unmanaged, high-value large-bodied sharks and rays the combination of very low population growth rates of manta rays, combined with the high value of their gill rakers and the international nature of trade, is highly likely to lead to rapid depletion and potential local extinction unless a rapid conservation management response occurs worldwide. Furthermore, we show that it is possible to derive important insights into the demography extinction risk of data-poor species using well-established life history theory.

  11. Evolutionary ecology of endocrine-mediated life-history variation in the garter snake Thamnophis elegans.

    PubMed

    Sparkman, Amanda M; Vleck, Carol M; Bronikowski, Anne M

    2009-03-01

    The endocrine system plays an integral role in the regulation of key life-history traits. Insulin-like growth factor-1 (IGF-1) is a hormone that promotes growth and reproduction, and it has been implicated in the reduction of lifespan. IGF-1 is also capable of responding plastically to environmental stimuli such as resource availability and temperature. Thus pleiotropic control of life-history traits by IGF-1 could provide a mechanism for the evolution of correlated life-history traits in a new or changing environment. An ideal system in which to investigate the role of IGF-1 in life-history evolution exists in two ecotypes of the garter snake Thamnophis elegans, which derive from a single recent ancestral source but have evolved genetically divergent life-history characteristics. Snakes from meadow populations near Eagle Lake, California (USA) exhibit slower growth rates, lower annual reproductive output, and longer median adult lifespans relative to populations along the lakeshore. We hypothesized that the IGF-1 system has differentiated between these ecotypes and can account for increased growth and reproduction and reduced survival in lakeshore vs. meadow snakes. We tested for a difference in plasma IGF-1 levels in free-ranging snakes from replicate populations of each ecotype over three years. IGF-1 levels were significantly associated with adult body size, reproductive output, and season in a manner that reflects established differences in prey ecology and age/size-specific reproduction between the ecotypes. These findings are discussed in the context of theoretical expectations for a tradeoff between reproduction and lifespan that is mediated by pleiotropic endocrine mechanisms.

  12. The Mass-Longevity Triangle: Pareto Optimality and the Geometry of Life-History Trait Space

    PubMed Central

    Szekely, Pablo; Korem, Yael; Moran, Uri; Mayo, Avi; Alon, Uri

    2015-01-01

    When organisms need to perform multiple tasks they face a fundamental tradeoff: no phenotype can be optimal at all tasks. This situation was recently analyzed using Pareto optimality, showing that tradeoffs between tasks lead to phenotypes distributed on low dimensional polygons in trait space. The vertices of these polygons are archetypes—phenotypes optimal at a single task. This theory was applied to examples from animal morphology and gene expression. Here we ask whether Pareto optimality theory can apply to life history traits, which include longevity, fecundity and mass. To comprehensively explore the geometry of life history trait space, we analyze a dataset of life history traits of 2105 endothermic species. We find that, to a first approximation, life history traits fall on a triangle in log-mass log-longevity space. The vertices of the triangle suggest three archetypal strategies, exemplified by bats, shrews and whales, with specialists near the vertices and generalists in the middle of the triangle. To a second approximation, the data lies in a tetrahedron, whose extra vertex above the mass-longevity triangle suggests a fourth strategy related to carnivory. Each animal species can thus be placed in a coordinate system according to its distance from the archetypes, which may be useful for genome-scale comparative studies of mammalian aging and other biological aspects. We further demonstrate that Pareto optimality can explain a range of previous studies which found animal and plant phenotypes which lie in triangles in trait space. This study demonstrates the applicability of multi-objective optimization principles to understand life history traits and to infer archetypal strategies that suggest why some mammalian species live much longer than others of similar mass. PMID:26465336

  13. Population transcriptomics of life-history variation in the genus Salmo.

    PubMed

    Giger, Thomas; Excoffier, Laurent; Amstutz, Ursula; Day, Philip J R; Champigneulle, Alexis; Hansen, Michael M; Kelso, Janet; Largiadèr, Carlo R

    2008-07-01

    In this study, we demonstrate the power of applying complementary DNA (cDNA) microarray technology to identifying candidate loci that exhibit subtle differences in expression levels associated with a complex trait in natural populations of a nonmodel organism. Using a highly replicated experimental design involving 180 cDNA microarray experiments, we measured gene-expression levels from 1098 transcript probes in 90 individuals originating from six brown trout (Salmo trutta) and one Atlantic salmon (Salmo salar) population, which follow either a migratory or a sedentary life history. We identified several candidate genes associated with preparatory adaptations to different life histories in salmonids, including genes encoding for transaldolase 1, constitutive heat-shock protein HSC70-1 and endozepine. Some of these genes clustered into functional groups, providing insight into the physiological pathways potentially involved in the expression of life-history related phenotypic differences. Such differences included the down-regulation of genes involved in the respiratory system of future migratory individuals. In addition, we used linear discriminant analysis to identify a set of 12 genes that correctly classified immature individuals as migratory or sedentary with high accuracy. Using the expression levels of these 12 genes, 17 out of 18 individuals used for cross-validation were correctly assigned to their respective life-history phenotype. Finally, we found various candidate genes associated with physiological changes that are likely to be involved in preadaptations to seawater in anadromous populations of the genus Salmo, one of which was identified to encode for nucleophosmin 1. Our findings thus provide new molecular insights into salmonid life-history variation, opening new perspectives in the study of this complex trait.

  14. Hormonal correlates of life history characteristics in wild female Colobus vellerosus.

    PubMed

    Vayro, J V; Fedigan, L M; Ziegler, T E; Crotty, A; Ataman, R; Clendenning, R; Potvin-Rosselet, E; Wikberg, E C; Sicotte, P

    2016-10-01

    Documenting primate life history characteristics is important because it provides information about traits that affect the timing and rate of reproduction in these long-lived species. This study describes the hormonal correlates of female reproductive events and quantifies for the first time key life history variables for Colobus vellerosus, using hormonal and observational data. This study also biologically validates that the reproductive events determined in the hormone profiles correspond to observed reproductive events for each female. We collected behavioural data on 18 females in our four study groups during 12 months (May 2012-2013) at the Boabeng-Fiema Monkey Sanctuary, using 10-min continuous focal and ad libitum sampling. We concurrently collected faecal samples (n = 1866) every 2-3 days from these 18 females (prepubescent n = 2, cycling n = 2, lactating n = 12, pregnant, n = 7, and post-reproductive n = 1) and extracted oestrogen (E2) and progesterone (P) metabolites in the field using solid-phase extraction cartridges. We created a hormone profile for each female by analyzing 1586 of our samples for E2 using radio-immuno assays, and P using enzyme-immunoassays at the Wisconsin National Primate Research Center. Mean ovarian cycle length was 24 days ± 1 (n = 2 cycles). Mean gestation length was 23 weeks (range = 21-25 weeks, n = 2 complete pregnancies). For females whose infants survived to nutritional independence, the mean inter-birth interval (IBI) was significantly longer than for females whose infants died prior to reaching nutritional independence (Mann-Whitney U Test; U = 14.5, p = 0.006; IBI surviving infants: 17.75 months, range = 8-20.75 months, n = 11 vs. IBI infant death: 11.89 months, range = 8-18.5 months, n = 9). The values for most life history traits reported in this study are similar to those documented in other similarly sized colobine species. Some values are on the lower end of the range for

  15. The Twentieth Century History of the Extraterrestrial Life Debate: Major Themes and Lessons Learned

    NASA Astrophysics Data System (ADS)

    Dick, Steven J.

    In this chapter we provide an overview of the extraterrestrial life debate since 1900, drawing largely on the major histories of the subject during this period, The Biological Universe (Dick 1996), Life on Other Worlds (Dick 1998), and The Living Universe (Dick and Strick 2004), as well as other published work. We outline the major components of the debate, including (1) the role of planetary science, (2) the search for planets beyond the solar system, (3) research on the origins of life, and (4) the Search for Extraterrestrial Intelligence (SETI). We emphasize the discovery of cosmic evolution as the proper context for the debate, reserving the cultural implications of astrobiology for part III of this volume. We conclude with possible lessons learned from this history, especially in the domains of the problematic nature of evidence, inference, and metaphysical preconceptions; the checkered role of theory; and an analysis of how representative general current arguments have fared in the past.

  16. The Societal Impact of Extraterrestrial Life: The Relevance of History and the Social Sciences

    NASA Astrophysics Data System (ADS)

    Dick, Steven J.

    This chapter reviews past studies on the societal impact of extraterrestrial life and offers four related ways in which history is relevant to the subject: the history of impact thus far, analogical reasoning, impact studies in other areas of science and technology, and studies on the nature of discovery and exploration. We focus particularly on the promise and peril of analogical arguments, since they are by necessity widespread in the field. This chapter also summarizes the relevance of the social sciences, particularly anthropology and sociology, and concludes by taking a closer look at the possible impact of the discovery of extraterrestrial life on theology and philosophy. In undertaking this study we emphasize three bedrock principles: (1) we cannot predict the future; (2) society is not monolithic, implying many impacts depending on religion, culture and worldview; (3) the impact of any discovery of extraterrestrial life is scenario-dependent.

  17. Flowering time and seed dormancy control use external coincidence to generate life history strategy.

    PubMed

    Springthorpe, Vicki; Penfield, Steven

    2015-03-31

    Climate change is accelerating plant developmental transitions coordinated with the seasons in temperate environments. To understand the importance of these timing advances for a stable life history strategy, we constructed a full life cycle model of Arabidopsis thaliana. Modelling and field data reveal that a cryptic function of flowering time control is to limit seed set of winter annuals to an ambient temperature window which coincides with a temperature-sensitive switch in seed dormancy state. This coincidence is predicted to be conserved independent of climate at the expense of flowering date, suggesting that temperature control of flowering time has evolved to constrain seed set environment and therefore frequency of dormant and non-dormant seed states. We show that late flowering can disrupt this bet-hedging germination strategy. Our analysis shows that life history modelling can reveal hidden fitness constraints and identify non-obvious selection pressures as emergent features.

  18. Early life stress affects limited regional brain activity in depression.

    PubMed

    Du, Lian; Wang, Jingjie; Meng, Ben; Yong, Na; Yang, Xiangying; Huang, Qingling; Zhang, Yan; Yang, Lingling; Qu, Yuan; Chen, Zhu; Li, Yongmei; Lv, Fajin; Hu, Hua

    2016-05-03

    Early life stress (ELS) can alter brain function and increases the risk of major depressive disorder (MDD) in later life. This study investigated whether ELS contributes to differences in regional brain activity between MDD patients and healthy controls (HC), as measured by amplitude of low-frequency fluctuation (ALFF)/fractional (f)ALFF. Eighteen first-episode, treatment-naïve MDD patients and HC were assessed with the Childhood Trauma Questionnaire and resting-state functional magnetic resonance imaging. We compared ALFF/fALFF between MDD patients and HC, with or without controlling for ELS, and determined whether ELS level was correlated with regional brain activity in each group. After regressing out ELS, we found that ALFF increased in bilateral amygdala and left orbital/cerebellum, while fALFF decreased in left inferior temporal and right middle frontal gyri in MDD patients relative to controls. ELS positively correlated with regional activity in the left cerebellum in MDD and in the right post-central/inferior temporal/superior frontal cingulate, inferior frontal gyrus and bilateral cerebellum in HC. Our findings indicate that there is only very limited region showing correlation between ELS and brain activity in MDD, while diverse areas in HC, suggesting ELS has few impacts on MDD patients.

  19. Early life stress affects limited regional brain activity in depression

    PubMed Central

    Du, Lian; Wang, Jingjie; Meng, Ben; Yong, Na; Yang, Xiangying; Huang, Qingling; Zhang, Yan; Yang, Lingling; Qu, Yuan; Chen, Zhu; Li, Yongmei; Lv, Fajin; Hu, Hua

    2016-01-01

    Early life stress (ELS) can alter brain function and increases the risk of major depressive disorder (MDD) in later life. This study investigated whether ELS contributes to differences in regional brain activity between MDD patients and healthy controls (HC), as measured by amplitude of low-frequency fluctuation (ALFF)/fractional (f)ALFF. Eighteen first-episode, treatment-naïve MDD patients and HC were assessed with the Childhood Trauma Questionnaire and resting-state functional magnetic resonance imaging. We compared ALFF/fALFF between MDD patients and HC, with or without controlling for ELS, and determined whether ELS level was correlated with regional brain activity in each group. After regressing out ELS, we found that ALFF increased in bilateral amygdala and left orbital/cerebellum, while fALFF decreased in left inferior temporal and right middle frontal gyri in MDD patients relative to controls. ELS positively correlated with regional activity in the left cerebellum in MDD and in the right post-central/inferior temporal/superior frontal cingulate, inferior frontal gyrus and bilateral cerebellum in HC. Our findings indicate that there is only very limited region showing correlation between ELS and brain activity in MDD, while diverse areas in HC, suggesting ELS has few impacts on MDD patients. PMID:27138376

  20. Reproductive and post-reproductive life history of wild-caught Drosophila melanogaster under laboratory conditions.

    PubMed

    Klepsatel, P; Gáliková, M; De Maio, N; Ricci, S; Schlötterer, C; Flatt, T

    2013-07-01

    The life history of the fruit fly (Drosophila melanogaster) is well understood, but fitness components are rarely measured by following single individuals over their lifetime, thereby limiting insights into lifetime reproductive success, reproductive senescence and post-reproductive lifespan. Moreover, most studies have examined long-established laboratory strains rather than freshly caught individuals and may thus be confounded by adaptation to laboratory culture, inbreeding or mutation accumulation. Here, we have followed the life histories of individual females from three recently caught, non-laboratory-adapted wild populations of D. melanogaster. Populations varied in a number of life-history traits, including ovariole number, fecundity, hatchability and lifespan. To descr