共查询到20条相似文献,搜索用时 15 毫秒
1.
Sabine M. Hille Caren B. Cooper 《Biological reviews of the Cambridge Philosophical Society》2015,90(1):204-213
Life‐history traits in birds, such as lifespan, age at maturity, and rate of reproduction, vary across environments and in combinations imposed by trade‐offs and limitations of physiological mechanisms. A plethora of studies have described the diversity of traits and hypothesized selection pressures shaping components of the survival–reproduction trade‐off. Life‐history variation appears to fall along a slow–fast continuum, with slow pace characterized by higher investment in survival over reproduction and fast pace characterized by higher investment in reproduction over survival. The Pace‐of‐Life Syndrome (POLS) is a framework to describe the slow–fast axis of variation in life‐history traits and physiological traits. The POLS corresponds to latitudinal gradients, with tropical birds exhibiting a slow pace of life. We examined four possible ways that the traits of high‐elevation birds might correspond to the POLS continuum: (i) rapid pace, (ii) tropical slow pace, (iii) novel elevational pace, or (iv) constrained pace. Recent studies reveal that birds breeding at high elevations in temperate zones exhibit a combination of traits creating a unique elevational pace of life with a central trade‐off similar to a slow pace but physiological trade‐offs more similar to a fast pace. A paucity of studies prevents consideration of the possibility of a constrained pace of life. We propose extending the POLS framework to include trait variation of elevational clines to help to investigate complexity in global geographic patterns. 相似文献
2.
Rassim Khelifa Rabah Zebsa Hichem Amari Mohammed Khalil Mellal Hayat Mahdjoub 《Journal of evolutionary biology》2019,32(9):943-954
Theory predicts that within‐population differences in the pace‐of‐life can lead to cohort splitting and produce marked intraspecific variation in body size. Although many studies showed that body size is positively correlated with fitness, many argue that selection for the larger body is counterbalanced by opposing physiological and ecological selective mechanisms that favour smaller body. When a population split into cohorts with different paces of life (slow or fast cohort), one would expect to detect the fitness–size relationship among and within cohorts, that is, (a) slower‐developing cohort has larger body size and higher fitness than faster‐developing cohort, and (b) larger individuals within each cohort show higher fitness than smaller individuals. Here, we test these hypotheses in capture–mark–recapture field surveys that assess body size, lifespan, survival and lifetime mating success in two consecutive generations of a partially bivoltine aquatic insect, Coenagrion mercuriale, where the spring cohort is slower‐developing than the autumn cohort. As expected, body size was larger in the slow‐developing cohort, which is consistent with the temperature‐size rule and also with the duration of development. Body size seasonal variation was greater in slow‐developing cohort most likely because of the higher variation in age at maturity. Concordant with theory, survival probability, lifespan and lifetime mating success were higher in the slow‐developing cohort. Moreover, individual body size was positively correlated with survival and mating success in both cohorts. Our study confirms the fitness costs of fast pace‐of‐life and the benefits of larger body size to adult fitness. 相似文献
3.
Rosemarie Kentie Sonya M. Clegg Shripad Tuljapurkar Jean‐Michel Gaillard Tim Coulson 《Ecology letters》2020,23(5):811-820
Fluctuating population density in stochastic environments can contribute to maintain life‐history variation within populations via density‐dependent selection. We used individual‐based data from a population of Soay sheep to examine variation in life‐history strategies at high and low population density. We incorporated life‐history trade‐offs among survival, reproduction and body mass growth into structured population models and found support for the prediction that different life‐history strategies are optimal at low and high population densities. Shorter generation times and lower asymptotic body mass were selected for in high‐density environments even though heavier individuals had higher probabilities to survive and reproduce. In contrast, greater asymptotic body mass and longer generation times were optimal at low population density. If populations fluctuate between high density when resources are scarce, and low densities when they are abundant, the variation in density will generate fluctuating selection for different life‐history strategies, that could act to maintain life‐history variation. 相似文献
4.
Justin R. Eastwood Michelle L. Hall Niki Teunissen Sjouke A. Kingma Nataly Hidalgo Aranzamendi Marie Fan Michael Roast Simon Verhulst Anne Peters 《Molecular ecology》2019,28(5):1127-1137
Poor conditions during early development can initiate trade‐offs that favour current survival at the expense of somatic maintenance and subsequently, future reproduction. However, the mechanisms that link early and late life‐history are largely unknown. Recently it has been suggested that telomeres, the nucleoprotein structures at the terminal end of chromosomes, could link early‐life conditions to lifespan and fitness. In wild purple‐crowned fairy‐wrens, we combined measurements of nestling telomere length (TL) with detailed life‐history data to investigate whether early‐life TL predicts fitness prospects. Our study differs from previous studies in the completeness of our fitness estimates in a highly philopatric population. The association between TL and survival was age‐dependent with early‐life TL having a positive effect on lifespan only among individuals that survived their first year. Early‐life TL was not associated with the probability or age of gaining a breeding position. Interestingly, early‐life TL was positively related to breeding duration, contribution to population growth and lifetime reproductive success because of their association with lifespan. Thus, early‐life TL, which reflects growth, accumulated early‐life stress and inherited TL, predicted fitness in birds that reached adulthood but not noticeably among fledglings. These findings suggest that a lack of investment in somatic maintenance during development particularly affects late life performance. This study demonstrates that factors in early‐life are related to fitness prospects through lifespan, and suggests that the study of telomeres may provide insight into the underlying physiological mechanisms linking early‐ and late‐life performance and trade‐offs across a lifetime. 相似文献
5.
Life‐history trade‐offs under different larval diets in Drosophila suzukii (Diptera: Drosophilidae) 下载免费PDF全文
Most larval drosophilids eat the microorganisms that develop in rotting fruit, a relatively protein‐rich resource. By contrast, the spotted‐wing Drosophila suzukii Matsumara (Diptera: Drosophilidae) uniquely develops in ripening fruit, a protein‐poor, carbohydrate‐rich resource. This shift in larval nutritional niche has led to D. suzukii being a significant agricultural pest in the U.S.A. and Europe. Although occupying a new niche may benefit a species by reducing competition, adaptation in host use may generate trade‐offs affecting fitness. To test the hypothesis that fitness trade‐offs will change with adaptation to novel larval diets, D. suzukii larval development on either a diet of a fresh, ripe blueberry (a natural host) or standard artificial Drosophila media (protein‐rich) is compared and the effect of diet on development time from egg to adult, adult body size and male wing spot area, and female fecundity is assessed. Larval development time differs, with larvae on the blueberry emerging as adults earlier than those on the artificial medium, although other fitness measures do not vary between the two diets. In addition, the faster development time on a blueberry does not trade off with body size as expected, although early fecundity is delayed in females that develop on blueberries. Thus, adaptation to a novel larval diet environment does not come at a cost to the ability to develop in protein‐rich resources. 相似文献
6.
Kyle M. Benowitz Ashley U. Amukamara Elizabeth C. Mckinney Allen J. Moore 《Ecological Entomology》2019,44(1):11-16
1. Burying beetles (Nicrophorus spp.) provide an excellent model system to test predictions about the relationships between environment, life‐history and behaviour. All species in the genus display similar natural histories, breeding on vertebrate carcasses and providing parental care to developing offspring. However, variations in other aspects of species' ecologies provide a rich framework to examine the evolution of parental behaviours and other traits. 2. One little‐studied species, N. sayi, breeds in substantially colder temperatures than its congeners, creating a potentially harsh environment for offspring. Here, we examined the timing of reproductive and developmental events in this species, and also investigated the effects of removing parents on offspring performance. 3. We find that development is not only extremely slow in this species, but it is also delayed even in comparison to other burying beetles reared at similar temperatures. However, the presence of parents reduces the time that offspring take to leave the carcass. This decrease in development time does not appear to result in a trade‐off with mortality or body size. 4. From these results, we suggest that very slow development may be advantageous when living in a particularly cold environment. Additionally, one role of extended parental care may be to assist offspring in dealing with these harsh conditions, and to mitigate the potentially negative consequences of adopting such a slow life‐history strategy. 相似文献
7.
Rainbow trout in seasonal environments: phenotypic trade‐offs across a gradient in winter duration 下载免费PDF全文
Ellen V. Lea Jonathan A. Mee John R. Post Sean M. Rogers Stephanie Mogensen 《Ecology and evolution》2015,5(21):4778-4794
Survival through periods of resource scarcity depends on the balance between metabolic demands and energy storage. The opposing effects of predation and starvation mortality are predicted to result in trade‐offs between traits that optimize fitness during periods of resource plenty (e.g., during the growing season) and those that optimize fitness during periods of resource scarcity (e.g., during the winter). We conducted a common environment experiment with two genetically distinct strains of rainbow trout to investigate trade‐offs due to (1) the balance of growth and predation risk related to foraging rate during the growing season and (2) the allocation of energy to body size prior to the winter. Fry (age 0) from both strains were stocked into replicate natural lakes at low and high elevation that differed in winter duration (i.e., ice cover) by 59 days. Overwinter survival was lowest in the high‐elevation lakes for both strains. Activity rate and growth rate were highest at high elevation, but growing season survival did not differ between strains or between environments. Hence, we did not observe a trade‐off between growth and predation risk related to foraging rate. Growth rate also differed significantly between the strains across both environments, which suggests that growth rate is involved in local adaptation. There was not, however, a difference between strains or between environments in energy storage. Hence, we did not observe a trade‐off between growth and storage. Our findings suggest that intrinsic metabolic rate, which affects a trade‐off between growth rate and overwinter survival, may influence local adaptation in organisms that experience particularly harsh winter conditions (e.g., extended periods trapped beneath the ice in high‐elevation lakes) in some parts of their range. 相似文献
8.
Selection and constraints on offspring size‐number trade‐offs in sand lizards (Lacerta agilis) 下载免费PDF全文
G. Ljungström M. Stjernstedt E. Wapstra M. Olsson 《Journal of evolutionary biology》2016,29(5):979-990
The trade‐off between offspring size and number is a central component of life‐history theory, postulating that larger investment into offspring size inevitably decreases offspring number. This trade‐off is generally discussed in terms of genetic, physiological or morphological constraints; however, as among‐individual differences can mask individual trade‐offs, the underlying mechanisms may be difficult to reveal. In this study, we use multivariate analyses to investigate whether there is a trade‐off between offspring size and number in a population of sand lizards by separating among‐ and within‐individual patterns using a 15‐year data set collected in the wild. We also explore the ecological and evolutionary causes and consequences of this trade‐off by investigating how a female's resource (condition)‐ vs. age‐related size (snout‐vent length) influences her investment into offspring size vs. number (OSN), whether these traits are heritable and under selection and whether the OSN trade‐off has a genetic component. We found a negative correlation between offspring size and number within individual females and physical constraints (size of body cavity) appear to limit the number of eggs that a female can produce. This suggests that the OSN trade‐off occurs due to resource constraints as a female continues to grow throughout life and, thus, produces larger clutches. In contrast to the assumptions of classic OSN theory, we did not detect selection on offspring size; however, there was directional selection for larger clutch sizes. The repeatabilities of both offspring size and number were low and we did not detect any additive genetic variance in either trait. This could be due to strong selection (past or current) on these life‐history traits, or to insufficient statistical power to detect significant additive genetic effects. Overall, the findings of this study are an important illustration of how analyses of within‐individual patterns can reveal trade‐offs and their underlying causes, with potential evolutionary and ecological consequences that are otherwise hidden by among‐individual variation. 相似文献
9.
Seasonal shifts along the oviparity–viviparity continuum in a cold‐climate lizard population 下载免费PDF全文
Squamate embryos require weeks of high temperature to complete development, with the result that cool climatic areas are dominated by viviparous taxa (in which gravid females can sun‐bask to keep embryos warm) rather than oviparous taxa (which rely on warm soil to incubate their eggs). How, then, can some oviparous taxa reproduce successfully in cool climates – especially late in summer, when soil temperatures are falling? Near the northern limit of their distribution (in Sweden), sand lizards (Lacerta agilis) shift tactics seasonally, such that the eggs in late clutches complete development more quickly (when incubated at a standard temperature) than do those of early clutches. That acceleration is achieved by a reduction in egg size and by an increase in the duration of uterine retention of eggs (especially, after cool weather). Our results clarify the ability of oviparous reptiles to reproduce successfully in cool climates and suggest a novel advantage to reptilian viviparity in such conditions: by maintaining high body temperatures, viviparous females may escape the need to reduce offspring size in late‐season litters. 相似文献
10.
Abstract 1. The majority of general life‐history models treat the environment as being invariable through time, even though temporal variation in selective agents could dramatically change the outcomes, e.g. in terms of optimal size and time at maturity. For herbivorous insects, seasonal differences in food quality are reasonably well described, but seasonal dynamics of top‐down selective forces are poorly documented. 2. The present study attempted to quantify seasonal changes in predation risk of folivorous insect larvae in temperate forest habitats. In a series of field experiments, artificial larvae were exposed to predators, and the resulting bird‐inflicted damage was recorded. The trials were repeated regularly throughout the course of two summers. 3. A distinct peak of larval mortality was recorded in mid‐June (the nestling period for most insectivorous passerine birds), after which predation risk declined to a plateau of 20–30% below the peak value. 4. The recorded pattern is interpreted as a consequence of seasonal changes in the number and behaviour of insectivorous birds, and the abundance of alternative food resources for these predators. 5. A quantitative analysis based on field data indicated that considering temporal variation in mortality in life‐history models is crucial for obtaining realistic predictions concerning central life‐history traits, such as final body size in different generations. 相似文献
11.
1. It was determined if the predatory midge Corethrella appendiculata Grabham imposes a fitness cost in a native mosquito, Ochlerotatus triseriatus Say, and an invasive mosquito, Aedes albopictus Skuse. The hypothesis that decreased activity of immature prey in the presence of predator cues is associated with life history costs through all life cycle stages was tested. 2. In experiment 1, individual larvae of O. triseriatus or A. albopictus were raised in the presence or absence of predation cues at two resource levels. Prey were video recorded to detect behavioural responses and to measure development time, size at emergence, and adult longevity. In experiment 2, prey populations were reared in similar environments and the frequency of predator cue additions was varied. 3. Only O. triseriatus reduced its activity in the presence of predation cues. Predation cues were associated with longer immature development times and shorter adult life spans in O. triseriatus, whereas in A. albopictus, the cues were associated with a larger size of emerging adults. 4. In the present study, it was found that behavioural modifications during the larval stage can affect mosquitoes through multiple stages of their complex life cycle. The species‐specific behavioural differences are probably attributable to the longer evolutionary history O. triseriatus has with predators, relative to the invasive A. albopictus. 相似文献
12.
The trade‐off between fecundity and egg size in a polymorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn,subarctic Norway 下载免费PDF全文
Reproductive traits differ between intralacustrine Arctic charr morphs. Here, we examine three sympatric lacustrine Arctic charr morphs with respect to fecundity, egg size and spawning time/site to assess reproductive investments and trade‐offs, and possible fitness consequences. The littoral omnivore morph (LO‐morph) utilizes the upper water for feeding and reproduction and spawn early in October. The large profundal piscivore morph (PP‐morph) and the small profundal benthivore morph (PB‐morph) utilize the profundal habitat for feeding and reproduction and spawn in December and November, respectively. Females from all morphs were sampled for fecundity and egg‐size analysis. There were large differences between the morphs. The PB‐morph had the lowest fecundity (mean = 45, SD = 13) and smallest egg size (mean = 3.2 mm, SD = 0.32 mm). In contrast, the PP‐morph had the highest fecundity (mean = 859.5, SD = 462) and the largest egg size (mean = 4.5 mm, SD = 0.46 mm), whereas the LO‐morph had intermediate fecundity (mean = 580, SD = 225) and egg size (mean = 4.3, SD = 0.24 mm). Fecundity increased with increasing body size within each morph. This was not the case for egg size, which was independent of body sizes within morph. Different adaptations to feeding and habitat utilization have apparently led to a difference in the trade‐off between fecundity and egg size among the three different morphs. 相似文献
13.
Individual variation in resource acquisition should have consequences for life‐history traits and trade‐offs between them because such variation determines how many resources can be allocated to different life‐history functions, such as growth, survival and reproduction. Since resource acquisition can vary across an individual's life cycle, the consequences for life‐history traits and trade‐offs may depend on when during the life cycle resources are limited. We tested for differential and/or interactive effects of variation in resource acquisition in the burying beetle Nicrophorus vespilloides. We designed an experiment in which individuals acquired high or low amounts of resources across three stages of the life cycle: larval development, prior to breeding and the onset of breeding in a fully crossed design. Resource acquisition during larval development and prior to breeding affected egg size and offspring survival, respectively. Meanwhile, resource acquisition at the onset of breeding affected size and number of both eggs and offspring. In addition, there were interactive effects between resource acquisition at different stages on egg size and offspring survival. However, only when females acquired few resources at the onset of breeding was there evidence for a trade‐off between offspring size and number. Our results demonstrate that individual variation in resource acquisition during different stages of the life cycle has important consequences for life‐history traits but limited effects on trade‐offs. This suggests that in species that acquire a fixed‐sized resource at the onset of breeding, the size of this resource has larger effects on life‐history trade‐offs than resources acquired at earlier stages. 相似文献
14.
A central assumption of life history theory is that the evolution of the component traits is determined in part by trade-offs between these traits. Whereas the existence of such trade-offs has been well demonstrated, the relative importance of these remains unclear. In this paper we use optimality theory to test the hypothesis that the trade-off between present and future fecundity induced by the costs of continued growth is a sufficient explanation for the optimal age at first reproduction, alpha, and the optimal allocation to reproduction, G, in 38 populations of perch and Arctic char. This hypothesis is rejected for both traits and we conclude that this trade-off, by itself, is an insufficient explanation for the observed values of alpha and G. Similarly, a fitness function that assumes a mortality cost to reproduction but no growth cost cannot account for the observed values of alpha. In contrast, under the assumption that fitness is maximized, the observed life histories can be accounted for by the joint action of trade-offs between growth and reproductive allocation and between mortality and reproductive allocation (Individual Juvenile Mortality model). Although the ability of the growth/mortality model to fit the data does not prove that this is the mechanism driving the evolution of the optimal age at first reproduction and allocation to reproduction, the fit does demonstrate that the hypothesis is consistent with the data and hence cannot at this time be rejected. We also examine two simpler versions of this model, one in which adult mortality is a constant proportion of juvenile mortality [Proportional Juvenile Mortality (PJM) model] and one in which the proportionality is constant within but not necessarily between species [Specific Juvenile Mortality (SSJM) model]. We find that the PJM model is unacceptable but that the SSJM model produces fits suggesting that, within the two species studied, juvenile mortality is proportional to adult mortality but the value differs between the two species. 相似文献
15.
Ornela De Gasperin Ana Duarte Sinead English Alfredo Attisano Rebecca M. Kilner 《Ecology and evolution》2019,9(1):339-351
We tested whether the early‐life environment can influence the extent of individual plasticity in a life‐history trait. We asked: can the early‐life environment explain why, in response to the same adult environmental cue, some individuals invest more than others in current reproduction? Moreover, can it additionally explain why investment in current reproduction trades off against survival in some individuals, but is positively correlated with survival in others? We addressed these questions using the burying beetle, which breeds on small carcasses and sometimes carries phoretic mites. These mites breed alongside the beetle, on the same resource, and are a key component of the beetle's early‐life environment. We exposed female beetles to mites twice during their lives: during their development as larvae and again as adults during their first reproductive event. We measured investment in current reproduction by quantifying average larval mass and recorded the female's life span after breeding to quantify survival. We found no effect of either developing or breeding alongside mites on female reproductive investment, nor on her life span, nor did developing alongside mites influence her size. In post hoc analyses, where we considered the effect of mite number (rather than their mere presence/absence) during the female's adult breeding event, we found that females invested more in current reproduction when exposed to greater mite densities during reproduction, but only if they had been exposed to mites during development as well. Otherwise, they invested less in larvae at greater mite densities. Furthermore, females that had developed with mites exhibited a trade‐off between investment in current reproduction and future survival, whereas these traits were positively correlated in females that had developed without mites. The early‐life environment thus generates individual variation in life‐history plasticity. We discuss whether this is because mites influence the resources available to developing young or serve as important environmental cues. 相似文献
16.
Dalial Freitak Toomas Tammaru Siiri‐Lii Sandre Hendrik Meister Toomas Esperk 《Journal of evolutionary biology》2019,32(7):653-665
Seasonal polyphenism constitutes a specific type of phenotypic plasticity in which short‐lived organisms produce different phenotypes in different times of the year. Seasonal generations of such species frequently differ in their overall lifespan and in the values of traits closely related to fitness. Seasonal polyphenisms provide thus excellent, albeit underused model systems for studying trade‐offs between life‐history traits. Here, we compare immunological parameters between the two generations of the European map butterfly (Araschnia levana), a well‐known example of a seasonally polyphenic species. To reveal possible costs of immune defence, we also examine the concurrent differences in several life‐history traits. Both in laboratory experiments and in the field, last instar larvae heading towards the diapause (overwintering) had higher levels of both phenoloxidase (PO) activity and lytic activity than directly developing individuals. These results suggest that individuals from the diapausing generation with much longer juvenile (pupal) period invest more in their immune system than those from the short‐living directly developing generation. The revealed negative correlation between pupal mass and PO activity may be one of the reasons why, in this species, the diapausing generation has a smaller body size than the directly developing generation. Immunological parameters may thus well mediate trade‐offs between body size‐related traits. 相似文献
17.
GREG W. MITCHELL NATHANIEL T. WHEELWRIGHT CHRISTOPHER G. GUGLIELMO D. RYAN NORRIS 《Ibis》2012,154(2):325-337
Costs of reproduction represent a common life‐history trade‐off. Critical to understanding these costs in migratory species is the ability to track individuals across successive stages of the annual cycle. We assessed the effects of total number of offspring fledged and date of breeding completion on pre‐migratory body condition, the schedule of moult and annual survival in a migratory songbird, the Savannah Sparrow Passerculus sandwichensis. Between 2008 and 2010, moult was delayed for individuals that finished breeding later in the breeding period and resulted in reduced lean tissue mass during the pre‐migratory period, suggesting an indirect trade‐off between the timing of breeding completion and condition just prior to migration. Lean tissue mass decreased as the number of offspring fledged increased in 2009, a particularly cool and wet year, illustrating a direct trade‐off between reproductive effort and condition just prior to migration in years when weather is poor. However, using a 17‐year dataset from the same population, we found that parents that fledged young late in the breeding period had the highest survival and that number of offspring fledged did not affect survival, suggesting that individuals do not experience long‐term trade‐offs between reproduction and survival. Taken together, our results suggest that adult Savannah Sparrows pay short‐term costs of reproduction, but that longer‐term costs are mitigated by individual quality, perhaps through individual variation in resource acquisition. 相似文献
18.
HOWARD P. RIESSEN 《Freshwater Biology》2012,57(7):1422-1433
1. Inducible defences are advantageous because they protect the prey while limiting associated fitness costs. The presence of these costs is an essential component of this conditional strategy, since their absence would favour constitutive (fixed) defences. In some cases, however, these costs have been difficult to measure because of complex interactions between the defences themselves, resultant life history changes and the organism’s environment. 2. The pond‐dwelling water flea, Daphnia pulex, forms defensive neck spines in response to kairomones released by predatory larvae of the phantom midge, Chaoborus. This predator–prey interaction and the formation of these inducible defences have been well studied, but costs associated with the development of neck spines remain unclear. In this study, I address this problem by analysing the effect of Chaoborus kairomones on the life history responses (and fitness costs associated with these responses) of two clones of D. pulex that are from the same pond population, but differ greatly in their degree of neck spine development. 3. Both D. pulex clones exhibited the same predator‐induced shifts in life history: larger size at birth, reduced juvenile growth rate (producing a smaller size at maturity), delayed reproduction and a reduction in the number of neonates produced after the first clutch. Relative fitness decreased significantly and to the same degree (c. 10% reduction in r) in each clone. This observed fitness cost was not directly related to the neck spines per se since the cost was the same in both clones, despite their considerable differences in neck spine development. Rather, it appears to be indirectly related to this antipredator morphology via a combination of delayed reproduction and a set of life history trade‐offs (decreased growth rate, decreased reproduction after the first clutch) for increased neonate body size, which is necessary for neck spines to be effective defences. This suite of induced responses is probably a result of local adaptation of these two D. pulex clones to their common pond environment. 4. Costs of inducible defences do not always entail direct allocation costs associated with forming and maintaining a defence, but may also involve indirect life history responses that are specific to particular environmental situations. This local adaptation would explain the highly variable life history responses observed among D. pulex clones from different pond environments. 相似文献
19.
M. MUGABO O. MARQUIS S. PERRET J. F. LE GALLIARD 《Journal of evolutionary biology》2010,23(9):1886-1898
Detailed studies of the mechanisms driving life history effects of food availability are of prime importance to understand the evolution of phenotypic plasticity and the capacity of organisms to produce better adapted phenotypes. Food availability may influence life history trajectories through three nonexclusive mechanisms: (i) immediate and long‐lasting effects on individual quality, and indirect delayed effects on (ii) intracohort and (iii) intercohort interactions. Using the common lizard (Zootoca vivipara), we tested whether a food deprivation during the two‐first months of life influence life history (growth, survival, reproduction) and performance traits (immunocompetence, locomotor performances) until adulthood. We investigated the underlying mechanisms and their possible interactions by manipulating jointly food availability in a birth cohort and in cohorts of older conspecifics. Food deprivation had direct immediate negative effects on growth but positive long‐lasting effects on immunocompetence. Food deprivation had also indirect delayed effects on growth, body size, early survival and reproduction mediated by an interaction between its direct effects on individual quality and its delayed effects on the intensity of intercohort social interactions combined with density dependence on body size. These results demonstrate that interactions between direct and socially mediated effects of past environments influence life history evolution in size‐structured and stage‐structured populations. 相似文献
20.
A broad range of mortality patterns has been documented across species, some even including decreasing mortality over age. Whether there exist a common denominator to explain both similarities and differences in these mortality patterns remains an open question. The disposable soma theory, an evolutionary theory of aging, proposes that universal intracellular trade‐offs between maintenance/lifespan and reproduction would drive aging across species. The disposable soma theory has provided numerous insights concerning aging processes in single individuals. Yet, which specific population mortality patterns it can lead to is still largely unexplored. In this article, we propose a model exploring the mortality patterns which emerge from an evolutionary process including only the disposable soma theory core principles. We adapt a well‐known model of genomic evolution to show that mortality curves producing a kink or mid‐life plateaus derive from a common minimal evolutionary framework. These mortality shapes qualitatively correspond to those of Drosophila melanogaster, Caenorhabditis elegans, medflies, yeasts and humans. Species evolved in silico especially differ in their population diversity of maintenance strategies, which itself emerges as an adaptation to the environment over generations. Based on this integrative framework, we also derive predictions and interpretations concerning the effects of diet changes and heat‐shock treatments on mortality patterns. 相似文献