Variation In Resource Acquisition Research Articles

Population Dynamic Consequences of Context-Dependent Trade-Offs across Life Histories.

AbstractTrade-offs are central to life history theory and play a role in driving life history diversity. They arise from a finite amount of resources that need to be allocated among different functions by an organism. Yet covariation of demographic rates among individuals frequently do not reflect allocation trade-offs because of variation in resource acquisition. The covariation of traits among individuals can thus vary with the environment and often increases in benign environments. Surprisingly, little is known about how such context-dependent expression of trade-offs among individuals affect population dynamics across species with different life histories. To study their influence on population stability, we develop an individual-based simulation where covariation in demographic rates varies with the environment. We use it to simulate population dynamics for various life histories across the slow-fast pace-of-life continuum. We found that the population dynamics of slower life histories are relatively more sensitive to changes in covariation, regardless of the trade-off considered. Additionally, we found that the impact on population stability depends on which trade-off is considered, with opposite effects of intraindividual and intergenerational trade-offs. Last, the expression of different trade-offs can feed back to influence generation time through selection acting on individual heterogeneity within cohorts, ultimately affecting population dynamics.

Information Gathering Is Associated with Increased Survival: A Field Experiment in Black-Capped Chickadees (Poecile atricapillus).

AbstractSampling, investing time or energy to learn about the environment, allows organisms to track changes in resource distribution and quality. The use of sampling is predicted to change as a function of energy expenditure, food availability, and starvation risk, all of which can vary both within and among individuals. We studied sampling behavior in a field study with black-capped chickadees (Poecile atricapillus) and show that individuals adjust their use of sampling as a function of ambient temperature (a proxy for energy expenditure), the presence of an alternative food source (yes or no, a proxy for risk of energy shortfall), and their interaction, as predicted by models of optimal sampling. We also observed repeatable differences in sampling. Some individuals consistently sampled more, and individuals that sampled more overall also had a higher annual survival. These results are consistent with among-individual differences in resource acquisition (e.g., food caches or dominance-related differences in priority access to feeders), shaping among-individual differences in both sampling and survival, with greater resource acquisition leading to both higher sampling and higher survival. Although this explanation requires explicit testing, it is in line with several recent studies suggesting that variation in resource acquisition is a key mechanism underlying animal personality.

Differences in resource acquisition, not allocation, mediate the relationship between behaviour and fitness: a systematic review and meta-analysis.

Within populations, individuals often show repeatable variation in behaviour, called 'animal personality'. In the last few decades, numerous empirical studies have attempted to elucidate the mechanisms maintaining this variation, such as life-history trade-offs. Theory predicts that among-individual variation in behavioural traits could be maintained if traits that are positively associated with reproduction are simultaneously associated with decreased survival, such that different levels of behavioural expression lead to the same net fitness outcome. However, variation in resource acquisition may also be important in mediating the relationship between individual behaviour and fitness components (survival and reproduction). For example, if certain phenotypes (e.g. dominance or aggressiveness) are associated with higher resource acquisition, those individuals may have both higher reproduction and higher survival, relative to others in the population. When individuals differ in their ability to acquire resources, trade-offs are only expected to be observed at the within-individual level (i.e. for a given amount of resource, if an individual increases its allocation to reproduction, it comes at the cost of allocation to survival, and vice versa), while among individuals traits that are associated with increased survival may also be associated with increased reproduction. We performed a systematic review and meta-analysis, asking: (i) do among-individual differences in behaviour reflect among-individual differences in resource acquisition and/or allocation, and (ii) is the relationship between behaviour and fitness affected by the type of behaviour and the testing environment? Our meta-analysis consisted of 759 estimates from 193 studies. Our meta-analysis revealed a positive correlation between pairs of estimates using both survival and reproduction as fitness proxies. That is, for a given study, behaviours that were associated with increased reproduction were also associated with increased survival, suggesting that variation in behaviour at the among-individual level largely reflects differences among individuals in resource acquisition. Furthermore, we found the same positive correlation between pairs of estimates using both survival and reproduction as fitness proxies at the phenotypic level. This is significant because we also demonstrated that these phenotypic correlations primarily reflect within-individual correlations. Thus, even when accounting for among-individual differences in resource acquisition, we did not find evidence of trade-offs at the within-individual level. Overall, the relationship between behaviour and fitness proxies was not statistically different from zero at the among-individual, phenotypic, and within-individual levels; this relationship was not affected by behavioural category nor by the testing condition. Our meta-analysis highlights that variation in resource acquisition may be more important in driving the relationship between behaviour and fitness than previously thought, including at the within-individual level. We suggest that this may come about via heterogeneity in resource availability or age-related effects, with higher resource availability and/or age leading to state-dependent shifts in behaviour that simultaneously increase both survival and reproduction. We emphasize that future studies examining the mechanisms maintaining behavioural variation in populations should test the link between behavioural expression and resource acquisition - both within and among individuals. Such work will allow the field of animal personality to develop specific predictions regarding the mediating effect of resource acquisition on the fitness consequences of individual behaviour.

Forage availability and maternal characteristics affect costs of reproduction in a large marsupial.

Life history theory predicts trade-offs in allocation between survival, maintenance, growth, and reproduction, especially when resources are scarce. Individual variation in resource acquisition can affect trade-offs, but is often unaccounted for. We quantified the fitness costs of reproduction, accounting for environmental conditions, maternal characteristics and individual variation. We analyzed 10years of data from marked kangaroos to evaluate how reproductive allocation affected annual mass change and skeletal growth, subsequent fecundity and weaning success, and survival, accounting for maternal mass or size and forage availability. Through repeated measurements of 76-91 females, we investigated how trade-offs varied within and between individuals, assessing whether individual variation could mask population-level trade-offs. In poor environments, females that weaned an offspring lost mass. Females that nursed an offspring for > 7months had reduced skeletal growth. Females that did not gain mass over the previous 12months rarely reproduced, especially if they had nursed an offspring for > 7months the previous year. Reproductive allocation had no effect on weaning success, which was very low, and did not affect maternal survival, suggesting a conservative strategy. Disentangling within- and between-individual responses revealed trade-offs within individuals, but because individuals did not vary in their responses to earlier effort, these trade-offs did not drive population trends. The interacting effects of environmental conditions, maternal characteristics and individual variation on allocation trade-offs demonstrate the importance of long-term monitoring for understanding life history variations in changing environments.

Lifetime Fitness in Wild Female Baboons: Trade-Offs and Individual Heterogeneity in Quality.

Understanding the evolution of life histories requires information on how life histories vary among individuals and how such variation predicts individual fitness. Using complete life histories for females in a well-studied population of wild baboons, we tested two nonexclusive hypotheses about the relationships among survival, reproduction, and fitness: the quality hypothesis, which predicts positive correlations between life-history traits, mediated by variation in resource acquisition, and the trade-off hypothesis, which predicts negative correlations between life-history traits, mediated by trade-offs in resource allocation. In support of the quality hypothesis, we found that females with higher rates of offspring survival were themselves better at surviving. Further, after statistically controlling for variation in female quality, we found evidence for two types of trade-offs: females who produced surviving offspring at a slower rate had longer life spans than those who produced surviving offspring at a faster rate, and females who produced surviving offspring at a slower rate had a higher overall proportion of offspring survive infancy than females who produced surviving offspring at a faster rate. Importantly, these trade-offs were evident even when accounting for (i) the influence of offspring survival on maternal birth rate, (ii) the dependence of offspring survival on maternal survival, and (iii) potential age-related changes in birth rate and/or offspring survival. Our results shed light on why trade-offs are evident in some populations while variation in individual quality masks trade-offs in others.

Effects of variation in resource acquisition during different stages of the life cycle on life-history traits and trade-offs in a burying beetle.

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.

Sexual Selection and Mixed Sex Expression: Adolescent Protandry, Phenotypic Tradeoffs and ‘Unconventional' Sex Allocation Estimates in a Protandric-Simultaneous Hermaphrodite

Background: In protandric-simultaneous (PS) hermaphrodites, individuals invariably reproduce as males first and later in life as simultaneous hermaphrodites. Here, the shrimp Lysmata wurdemanni was used as a model to (i) test for the role of sexual selection (male-male competition) in explaining the early male phase and size-dependent sex allocation (SDSA) in PS hermaphrodites, (ii) examine the tradeoff between the male and female function in hermaphrodites, and (iii) determine if SDSA also takes place in the form of sex-specific behaviors and anatomical structures. Results: In L. wurdemanni, male mating ability was size- and sex-dependent; greater for small than for large hermaphrodites and for males than hermaphrodites matched in body size. The above explains the adaptive value of the early male phase in PS hermaphrodites; small individuals should speed up sperm production and delay female reproduction to profit from male mating opportunities that are the greatest when small. Size-dependent male mating ability also suggests that small hermaphrodites should produce proportionally more sperm than ova compared to large hermaphrodites, a prediction supported by data. Sex allocation, measured as sex-specific behaviors and anatomical structures, was also size-dependent. No tradeoff between ova and sperm mass was found. However, among-individual variation in resource acquisition was considerable, suggesting that the observed lack of a statistical relationship between sperm and ova mass does not necessarily imply the absence of sex allocation tradeoffs in L. wurdemanni. Conclusion: Sexual selection is most relevant in PS hermaphrodites, SDSA also involves sex-specific behaviors and morphological features, and variation in resource acquisition and allocation can explain the apparent absence of sex allocation tradeoffs.

Multiple biological mechanisms result in correlations between pre- and post-mating traits that differ among versus within individuals and genotypes.

Reproductive traits involved in mate acquisition (pre-mating traits) are predicted to covary with those involved in fertilization success (post-mating traits). Variation in male quality may give rise to positive, and resource allocation trade-offs to negative, covariances between pre- and post-mating traits. Empirical studies have yielded mixed results. Progress is hampered as researchers often fail to appreciate that mentioned biological mechanisms can act simultaneously but at different hierarchical levels of biological variation: genetic correlations may, for example, be negative due to genetic trade-offs but environmental correlations may instead be positive due to individual variation in resource acquisition. We measured pre-mating (aggression, body weight) and post-mating (ejaculate size) reproductive traits in a pedigreed population of southern field crickets (Gryllus bimaculatus). To create environmental variation, crickets were raised on either a low or a high nymphal density treatment. We estimated genetic and environmental sources of correlations between pre- and post-mating traits. We found positive genetic correlations between pre- and post-mating traits, implying the existence of genetic variation in male quality. Over repeated trials of the same individual (testing order), positive changes in one trait were matched with negative changes in other traits, suggesting energy allocating trade-offs within individuals among days. These findings demonstrate the need for research on pre- and post-mating traits to consider the hierarchical structure of trait correlations. Only by doing so was our study able to conclude that multiple mechanisms jointly shape phenotypic associations between pre- and post-mating traits in crickets.

The pace-of-life syndrome revisited: the role of ecological conditions and natural history on the slow-fast continuum

The pace-of-life syndrome (i.e., POLS) hypothesis posits that behavioral and physiological traits mediate the trade-off between current and future reproduction. This hypothesis predicts that life history, behavioral, and physiological traits will covary under clearly defined conditions. Empirical tests are equivocal and suggest that the conditions necessary for the POLS to emerge are not always met. We nuance and expand the POLS hypothesis to consider alternative relationships among behavior, physiology, and life history. These relationships will vary with the nature of predation risk, the challenges posed by resource acquisition, and the energy management strategies of organisms. We also discuss how the plastic response of behavior, physiology, and life history to changes in ecological conditions and variation in resource acquisition among individuals determine our ability to detect a fast-slow pace of life in the first place or associations among these traits. Future empirical studies will provide most insights on the coevolution among behavior, physiology, and life history by investigating these traits both at the genetic and phenotypic levels in varying types of predation regimes and levels of resource abundance. We revisit the pace-of-life syndrome hypothesis, suggesting that behaviors involving a risk of death or injury should coevolve with higher metabolic rates, higher fecundity, faster growth, and heightened mortality rates. Empirical support for this hypothesis is mixed. We show how relaxing some of the assumptions underlying the pace-of-life syndrome hypothesis allows us to consider alternative relationships among behavior, physiology, and life history, and why we fail to meet the predictions posed by the pace-of-life syndrome hypothesis in some populations. Our discussion emphasizes the need to re-integrate the role of the species’ natural history, ecological conditions, and phenotypic plasticity in shaping relationships among behavior, physiology, and life history.

Experimental tests of the tolerated theft and risk-reduction theories of resource exchange.

Here we report the results of an experiment that tests the reciprocal risk reduction 1 and 'tolerated theft' or taking hypotheses 2 for why the human species is unique in having extensive exchange of resources among non-kin. We designed an experiment to determine whether, in response to variance of resource acquisition, people exchange food resources via taking or, alternatively, form reciprocal relationships based on giving. In the experiment, subjects forage individually, experience variation in resource acquisition, and then consume either by actions in which resources are taken from, or moved to, others in a group environment. The key feature of the experimental design is that individuals can transfer resources to others, attempt to take resources from others and defend against take-away attempts. Many subjects begin by attempting to take resources from others, who can resist those attempts at a cost to each. Over time, subjects shift to a cooperative strategy of voluntary reciprocal giving, a response not suggested by the instructions. These results provide evidence that people are independently able to overcome initial use of taking strategies, evaluate gains from exchange, and create endogenous reciprocal trading relationships as a response to unsynchronized variance in resource availability.

Sexual competition and the evolution of condition-dependent ageing

Increased individual resources (condition) can be correlated with either increased or decreased longevity. While variation in resource acquisition and allocation can account for some of this variation, the general conditions that select for either pattern remain unclear. Previous models suggest that nonlinearity of payoffs from investment in reproduction (e.g., male secondary sexual traits) can select for high‐condition individuals that sacrifice longevity to increase reproductive opportunity. However, it remains unclear what mating systems or patterns of sexual competition might select for such life‐history strategies. We used a model of condition‐dependent investment to explore how expected payoffs from increased expression of secondary sexual traits affect optimal investment in lifespan. We find that nonlinearity of these payoffs results in a negative relationship between condition and lifespan under two general conditions: first, when there are accelerating marginal benefits from increasing investment; second, when individuals that invest minimally in secondary sexual trait expression can still achieve matings. In the second scenario, the negative relationship occurs due to selection on low‐condition individuals to extend lifespan at the cost of secondary sexual trait expression. Our findings clarify the potential role of sexual selection in shaping patterns of condition‐dependent ageing, and highlight the importance of considering the strategies of both low‐ and high‐condition individuals when investigating patterns of condition‐dependent ageing.

Telomere attrition and growth: a life-history framework and case study in common terns.

The relationship between growth and age-specific telomere length, as a proxy of somatic state, is increasingly investigated, but observed patterns vary and a predictive framework is lacking. We outline expectations based on the assumption that telomere maintenance is costly and argue that individual heterogeneity in resource acquisition is predicted to lead to positive covariance between growth and telomere length. However, canalization of resource allocation to the trait with a larger effect on fitness, rendering that trait relatively invariant, can cause the absence of covariance. In a case study of common tern (Sterna hirundo) chicks, in which hatching order is the main determinant of variation in resource acquisition within broods, we find that body mass, but not telomere length or attrition, varies with hatching order. Moreover, body mass and growth positively predict survival to fledging, whereas telomere length and attrition do not. Using a novel statistical method to quantify standardized variance in plasticity, we estimate between-individual variation in telomere attrition to be only 12% of that of growth. Consistent with the relative invariance of telomere attrition, we find no correlation between age-specific body mass or growth and telomere attrition. We suggest that common tern chicks prioritize investment in long-term somatic state (as indicated by canalization of telomere maintenance) over immediate survival benefits of growth as part of an efficient brood reduction strategy that benefits the parents. As such, interspecific variation in the growth-telomere length relationship may be explained by the extent to which parents benefit from rapid mortality of excess offspring.

The survival–reproduction association becomes stronger when conditions are good

Positive covariations between survival and reproductive performance (S-R covariation) are generally interpreted in the context of fixed or dynamic demographic heterogeneity (i.e. persistent differences between individuals, or dynamic variation in resource acquisition), but the processes underlying covariations are still unknown. We used multi-event modelling to investigate how environmental and individual features influence S-R covariation patterns in a long-lived seabird, the Monteiro's storm petrel (Oceanodroma monteiroi). Our analysis reveals that a strong positive association between individual breeding success and subsequent survival occurs only when conditions are favourable to reproduction (in favourable years, in high-quality nests and in nest-faithful breeders). This finding reflects differences in the main causes of breeding failure and mortality under favourable and unfavourable conditions, which in turn lead to distinct patterns of S-R covariation. We suggest, in particular, that resource-related sources of demographic heterogeneity do not generate a strong S-R covariation, in contrast with hidden and unpredictable sources of variation.

Sex differences in the effects of juvenile and adult diet on age-dependent reproductive effort.

Sexual selection should cause sex differences in patterns of resource allocation. When current and future reproductive effort trade off, variation in resource acquisition might further cause sex differences in age-dependent investment, or in sensitivity to changes in resource availability over time. However, the nature and prevalence of sex differences in age-dependent investment remain unclear. We manipulated resource acquisition at juvenile and adult stages in decorated crickets, Gryllodes sigillatus, and assessed effects on sex-specific allocation to age-dependent reproductive effort (calling in males, fecundity in females) and longevity. We predicted that the resource and time demands of egg production would result in relatively consistent female strategies across treatments, whereas male investment should depend sharply on diet. Contrary to expectations, female age-dependent reproductive effort diverged substantially across treatments, with resource-limited females showing much lower and later investment in reproduction; the highest fecundity was associated with intermediate lifespans. In contrast, long-lived males always signalled more than short-lived males, and male age-dependent reproductive effort did not depend on diet. We found consistently positive covariance between male reproductive effort and lifespan, whereas diet altered this covariance in females, revealing sex differences in the benefits of allocation to longevity. Our results support sex-specific selection on allocation patterns, but also suggest a simpler alternative: males may use social feedback to make allocation decisions and preferentially store resources as energetic reserves in its absence. Increased calling effort with age therefore could be caused by gradual resource accumulation, heightened mortality risk over time, and a lack of feedback from available mates.

Maternal food quantity affects offspring feeding rate in Daphnia magna.

Maternal effects have wide-ranging effects on life-history traits. Here, using the crustacean Daphnia magna, we document a new effect: maternal food quantity affects offspring feeding rate, with low quantities of food triggering mothers to produce slow-feeding offspring. Such a change in the rate of resource acquisition has broad implications for population growth or dynamics and for interactions with, for instance, predators and parasites. This maternal effect can also explain the previously puzzling situation that the offspring of well-fed mothers, despite being smaller, grow and reproduce better than the offspring of food-starved mothers. As an additional source of variation in resource acquisition, this maternal effect may also influence relationships between life-history traits, i.e. trade-offs, and thus constraints on adaptation. Maternal nutrition has long-lasting effects on health and particularly diet-related traits in humans; finding an effect of maternal nutrition on offspring feeding rate in Daphnia highlights the utility of this organism as a powerful experimental model for exploring the relationship between maternal diet and offspring fitness.

Phenotypic variation in resource acquisition influences trade‐off between number and mass of offspring in a burying beetle

AbstractUnderstanding the consequences of phenotypic variation in resource acquisition is an important problem in evolutionary ecology because such variation may impact on how parents balance resource investment in individual offspring against other life‐history priorities. Here we investigate the effects of phenotypic variation in resource acquisition on the number and mass of offspring and the trade‐off between the two in the burying beetle Nicrophorus vespilloides. We manipulate resource acquisition in adults by providing some females with a small mouse carcass (5–10 g) and other females with a large mouse carcass (15–20 g). We found that females breeding on larger carcasses produced both more and larger offspring than females breeding on smaller carcasses. Furthermore, an increase in brood size had a stronger negative effect on offspring mass in broods produced on smaller carcasses than in broods produced on larger carcasses. We conclude that phenotypic variation in resource acquisition had a strong effect on the number and mass of offspring and the trade‐off between the two. Our study contributes to our understanding of phenotypic variation in resource acquisition by showing that females with more resources produce both more and larger offspring in situations where such variation is not associated with anatomical or physiological differences between females.

QTL architecture of reproductive fitness characters in Brassica rapa

BackgroundReproductive output is critical to both agronomists seeking to increase seed yield and to evolutionary biologists interested in understanding natural selection. We examine the genetic architecture of diverse reproductive fitness traits in recombinant inbred lines (RILs) developed from a crop (seed oil) × wild-like (rapid cycling) genotype of Brassica rapa in field and greenhouse environments.ResultsSeveral fitness traits showed strong correlations and QTL-colocalization across environments (days to bolting, fruit length and seed color). Total fruit number was uncorrelated across environments and most QTL affecting this trait were correspondingly environment-specific. Most fitness components were positively correlated, consistent with life-history theory that genotypic variation in resource acquisition masks tradeoffs. Finally, we detected evidence of transgenerational pleiotropy, that is, maternal days to bolting was negatively correlated with days to offspring germination. A QTL for this transgenerational correlation was mapped to a genomic region harboring one copy of FLOWERING LOCUS C, a genetic locus known to affect both days to flowering as well as germination phenotypes.ConclusionsThis study characterizes the genetic structure of important fitness/yield traits within and between generations in B. rapa. Several identified QTL are suitable candidates for fine-mapping for the improvement of yield in crop Brassicas. Specifically, brFLC1, warrants further investigation as a potential regulator of phenology between generations.

Quantifying multivariate plasticity: genetic variation in resource acquisition drives plasticity in resource allocation to components of life history

Acquisition and allocation of resources are central to life-history theory. However, empirical work typically focuses only on allocation despite the fact that relationships between fitness components may be governed by differences in the ability of individuals to acquire resources across environments. Here, we outline a statistical framework to partition the genetic basis of multivariate plasticity into independent axes of genetic variation, and quantify for the first time, the extent to which specific traits drive multitrait genotype-environment interactions. Our framework generalises to analyses of plasticity, growth and ageing. We apply this approach to a unique, large-scale, multivariate study of acquisition, allocation and plasticity in the life history of the cricket, Gryllus firmus. We demonstrate that resource acquisition and allocation are genetically correlated, and that plasticity in trade-offs between allocation to components of fitness is 90% dependent on genetic variance for total resource acquisition. These results suggest that genotype-environment effects for resource acquisition can maintain variation in life-history components that are typically observed in the wild.

Geographic variation in resource allocation to the abdomen in geometrid moths

A resource allocation trade-off is expected when resources from a common pool are allocated to two or more traits. In holometabolous insects, resource allocation to different functions during metamorphosis relies completely on larval-derived resources. At adult eclosion, resource allocation to the abdomen at the expense of other body parts can be seen as a rough estimate of resource allocation to reproduction. Theory suggests geographic variation in resource allocation to the abdomen, but there are currently no empirical data on it. We measured resource allocation to the abdomen at adult eclosion in four geometrid moths along a latitudinal gradient. Resource (total dry material, carbon, nitrogen) allocation to the abdomen showed positive allometry with body size. We found geographic variation in resource allocation to the abdomen in each species, and this variation was independent of allometry in three species. Geographic variation in resource allocation to the abdomen was complex. Resource allocation to the abdomen was relatively high in partially bivoltine populations in two species, which fits theoretical predictions, but the overall support for theory is weak. This study indicates that the geographic variation in resource allocation to the abdomen is not an allometric consequence of geographic variation in resource acquisition (i.e., body size). Thus, there is a component of resource allocation that can evolve independently of resource acquisition. Our results also suggest that there may be intraspecific variation in the degree of capital versus income breeding.

Reproductive allocation strategies: a long-term study on proximate factors and temporal adjustments in a viviparous lizard

Optimisation of reproductive investment is crucial for Darwinian fitness, and detailed long-term studies are especially suited to unravel reproductive allocation strategies. Allocation strategies depend on the timing of resource acquisition, the timing of resource allocation, and trade-offs between different life-history traits. A distinction can be made between capital breeders that fuel reproduction with stored resources and income breeders that use recently acquired resources. In capital breeders, but not in income breeders, energy allocation may be decoupled from energy acquisition. Here, we tested the influence of extrinsic (weather conditions) and intrinsic (female characteristics) factors during energy storage, vitellogenesis and early gestation on reproductive investment, including litter mass, litter size, offspring mass and the litter size and offspring mass trade-off. We used data from a long-term study of the viviparous lizard, Lacerta (Zootoca) vivipara. In terms of extrinsic factors, rainfall during vitellogenesis was positively correlated with litter size and mass, but temperature did not affect reproductive investment. With respect to intrinsic factors, litter size and mass were positively correlated with current body size and postpartum body condition of the previous year, but negatively with parturition date of the previous year. Offspring mass was negatively correlated with litter size, and the strength of this trade-off decreased with the degree of individual variation in resource acquisition, which confirms theoretical predictions. The combined effects of past intrinsic factors and current weather conditions suggest that common lizards combine both recently acquired and stored resources to fuel reproduction. The effect of past energy store points out a trade-off between current and future reproduction.