Variation In Resource Allocation Research Articles

Functional traits are more strongly correlated with biomass than diameter growth

Abstract The functional basis of tree growth is often evaluated based on trunk diameter even though diameter is only one dimension of growth that may not be an integrative measure of resource allocation. We tested the hypothesis that growth—functional trait relationships are stronger when key sources of variation in tree growth are also accounted for, namely tree height and DBH, as well as size‐related variation in wood density and seed production using data from 3881 trees of 24 species in a subtropical forest using ordinary least square regression and standard major axis regression. Wood density varied with tree size for 14 of 24 species, generally increasing with size. For 18 of 24 species, the correlations of leaf mass per area and an index of photosynthetic investment (PI) with biomass growth was stronger than with diameter growth rate. Juveniles did not show stronger relationships than adults but biomass growth adding up with seed production showed stronger relationships with PI than biomass growth alone for three of eight species. Synthesis. Thus, our study helps resolve a paradox of trait‐based ecology, that is, weak growth—trait relationships, as stronger relationships emerged when accounting for more sources of intraspecific, among‐tree variation in resource allocation.

Risk-taking neonates do not pay a survival cost in a free-ranging large mammal, the fallow deer (Dama dama).

Recent debate has focused on whether variation in personality primarily reflects variation in resource allocation or resource acquisition of individuals. These two mechanisms predict different relationships between personality and survival. If personality mainly reflects variation in resource allocation, then bold (i.e. risk-taking) individuals are expected to live shorter lives, whereas the opposite pattern is expected with resource acquisition. Here we studied the relationship between neonate personality and early-life survival in 269 juveniles of a population of fallow deer (Dama dama). We found that bolder individuals paid no apparent survival cost. Interestingly, among-individual differences in the physiological response at capture (heart rates, which covary with the behavioural response, i.e. latency to leave) were linked to survival, where individuals with lower heart rates when handled by humans had a higher probability of early-life survival. This suggests that bolder individuals may be of higher state than their shyer counterparts. As the first study linking neonate personality to survival in a free-ranging mammal, we provide novel insights into drivers behind early-life individual variation.

Provider Discretion and Variation in Resource Allocation: The Case of Triage Decisions

One of the most challenging environments in health care is the emergency department (ED) A key decision-maker in that context is triage nurses, who assess patient illness severity and influence wait times for medical attention. We gather novel data on the triage process across 108 EDs, including wait times, triage nurse identities and assessments, and detailed patient information and outcomes. Using quasi-random assignment to ED, we find a striking rate of “inversions,” where patients who are sicker based on either ex ante information or ex post outcomes are scored as sicker and wait longer than their healthier counterparts.

Variation in resource allocation in urgent and emergency Care Systems in Ireland

BackgroundA key challenge for most systems is how to provide effective access to urgent and emergency care across rural and urban populations. Tensions about the placement and scope of hospital emergency services are longstanding in Irish political life and there has been recent reform to centralise hospital services in some regions. The focus of this paper is a system approach to examine the geographic variation in resourcing and utilisation of such care across GP practices, out-of-hours care, ambulance services, Emergency Departments and Local Injury Units in Ireland.MethodsWe used a cross-sectional study design to evaluate variation in resource allocation by aggregating geographic funding to various elements of the urgent and emergency care system and assessing patterns in hospital resource utilisation across the population. Expenditure, staffing, access and activity data were gathered from government sources, individual facilities and service providers, health professional bodies, private firms and central statistics. Data on costs and activity in 2014 are collated and presented at both county and regional levels. Analyses focus on resources spent on urgent and emergency care across geographic areas, the role of population concentration in allocation, the relationship between pre-hospital spending and in-hospital spending, and the utilisation of hospital-based emergency care resources by residents of each county.ResultsAn array of funding mechanisms exists, resulting in a fragmented approach to the resourcing of urgent and emergency care. There are large differences in spending per capita at the county-level, ranging from between €50 and €200 per capita; however, these are less pronounced regionally. Distribution of hospital emergency care resources is highly skewed to the North East of the country, and away from the recently reconfigured South and Mid-West regions.ConclusionsThis analysis advances the traditional approach of evaluating individual services or hospital resourcing. There are notable differences in utilisation of hospital-based emergency care resources at the regional level, indicating that populations within those regions which have been reconfigured have lower utilisation of hospital resources. There is a clear case for more integration in decision-making around funding and consideration of key principles, such as equity, to guide that process.

Changes in Reproductive Strategy of an Early Successional Species Penthorum chinense in Response to Nutrient and Moisture Levels

Variation in resource allocation to clonal growth versus sexual reproduction suggests that plants have different adaptive strategies in response to environmental conditions such as nutrient availability and soil moisture. Seeds of P. chinense might play an important role in expanding its established populations. We hypothesize that an early successional perennial plant Penthorum chinense Pursh with many seeds and small rhizomes does not increase its allocation to rhizome propagules and/or decrease its allocation to seeds under sufficient nutrient content or moisture conditions, unlike many other perennials. We performed mesocosm experiments to understand how P. chinense could alter resource allocation to rhizomes and seeds under experimental manipulation of water and nutrient availability. Like many perennials, P. chinense contained more rhizome dry mass and rhizome mass fraction under favorable nutrient content condition than with relatively low nutrient levels. However, P. chinense did not decrease its allocation to seeds under sufficient nutrient condition. It did not change its allocation to rhizome propagules or seeds under high moisture level either, unlike other perennials. These results suggest that both rhizomes and seeds of P. chinense might be important for expanding its established populations.

Distribution of Local Social Services and Territorial Justice: the Case of Estonia

AbstractDistribution of public resources has always been a central issue in public policy. The question of spatial variation in resource allocation as a reflection of differing local conditions is particularly important in decentralised countries with a large number of subunits. On the local level, studies have shown variations in distribution of local welfare but have usually focused on single social policy fields and/or target groups, and often ignored territorial structures. By taking Estonia as a case, this study investigates whether and how the distribution of a range of social services and the structure of disaggregated local social spending corresponds to local socio-demographic conditions. We identify municipal clusters and analyse service provision and social spending on vulnerable groups within them. We use a spatial perspective by taking into consideration the distinction of rural-urban and core-peripheral settings. We show that resource allocation in Estonian municipalities mirrors quite well local socio-demographic structures but the division of municipalities between towns and rural municipalities used in the common discourse of local social policy is too simplified.

Cyclical and Structural Variation in Resource Allocation: Evidence for Europe

This paper uses cross-country micro-aggregated data on firm dynamics and productivity from the ECB CompNet database to provide empirical evidence on factor reallocation in the European Union (EU). The analysis finds that reallocation is towards more productive firms although the magnitude varies across countries and over time. Variation in reallocation is related to structural differences in firm size distribution across countries as well as to variation in labor and product market institutions. Productivity-enhancing reallocation generally rises in downturns but, similar to findings for the US, it did not pick up in the Great Recession. The sharp drop in exports and tightness in credit markets are seen to provide a partial explanation for this lack of a silver lining. JEL Classification: E24, E32, J63, O4

Growing more positive with age: The relationship between reproduction and survival in aging flies

Populations of laboratory animals that are selected for increased lifespan often show negative correlated responses in early fecundity. However, late fecundity and/or total lifetime fecundity can be higher in the populations selected for increased lifespan. This has been interpreted by some as being at odds with the disposable soma theory, which predicts decreased lifespan to increase total reproductive output. Alternatively, the Y–model explores the effects of variation in resource allocation and acquisition on life histories. In this model, a negative relationship between lifespan and reproduction can be viewed as variation in allocation, whereas a positive relationship is the result of variation in acquisition. However, a frequently neglected complication of the Y-model is that older individuals often show a decline in resource acquisition. Therefore, differential allocation to maintenance and survival might affect this decline in late-life acquisition which will affect resource availability across the whole lifespan. In this paper we show that a model which incorporates the ideas of the Y-model, the disposable soma theory, and an age-related decrease in resource acquisition, i.e. feeding senescence, can explain how the relationship between fecundity and lifespan changes with age. Furthermore, by modeling environments with contrasting extrinsic mortality rates, we explored how the outcome of the model depended on the relative importance of early and late-life reproduction. In high mortality environments a relatively higher early fecundity, lower late fecundity, and lower lifespans were more optimal, whereas the opposite was true for low mortality environments. We applied predictions from the model to a cohort of individually-housed female Drosophila melanogaster flies for which we measured age specific fecundity and lifespan. Early fecundity was negatively associated with lifespan, while late fecundity related positively with lifespan in the same cohort. This verified that the mechanism of feeding senescence could explain patterns for age specific relationships between lifespan and fecundity.

Neighborhood Variation in the Utilization of Laparoscopy for the Treatment of Colon Cancer.

The rates of laparoscopic colectomy for colon cancer have steadily increased since its inception. Laparoscopic colectomy currently accounts for a third of colectomy procedures in the United States, but little is known regarding the spatial pattern of the utilization of laparoscopy for colon cancer. This study evaluated the utilization of laparoscopy for colon cancer at the neighborhood level in Ontario. Retrospective analysis of prospectively collected data was performed. This study was conducted at all hospitals in the province of Ontario. This population-based study included all patients aged ≥18 who received an elective colectomy for colon cancer from April 2008 until March 2012 in the province of Ontario. The primary outcome measure was the neighborhood rates of laparoscopy. Overall, 9,969 patients underwent surgery, and the cluster analysis identified 74 cold-spot neighborhoods, representing 1.8 million people, or 14% of the population. In the multivariate analysis, patients from rural neighborhoods were less than half as likely to receive laparoscopy, OR 0.44 (95% CI, 0.24-0.84; p = 0.012). Additionally, having a minimally invasive surgery fellowship training facility within the same administrative health region as the neighborhood made it more than 23 times as likely to be a hot spot, OR 25.88 (95% CI, 12.15-55.11; p < 0.001). Neighborhood socioeconomic status was not associated with variation in the utilization of laparoscopy. Patient case mix could affect laparoscopy use. This study identified an unequal utilization of laparoscopy for colon cancer within Ontario with rural neighborhoods experiencing low rates of laparoscopic colectomy, whereas neighborhoods in the same administrative region as minimally invasive surgery training centers experienced increased utilization. Further study into the causes of this variation in resource allocation is needed to identify ways to improve more efficient spread of knowledge and technical skills advancement.

Resource allocation in Copaifera langsdorffii (Fabaceae): how supra-annual fruiting affects plant traits and herbivory?

Plants have limited resources to invest in reproduction, vegetative growth and defense against herbivorous. Trade-off in resources allocation promotes changes in plant traits that may affect higher trophic levels. In this study, we evaluated the trade-off effect between years of high and low fruiting on the investment of resources for growth and defense, and their indirect effects on herbivory in Copaifera langsdorffii. Our questions were: (i) does the resource investment on reproduction causes a depletion in vegetative growth as predicted by the Carbon/Nutrient Balance hypothesis (CNBH), resulting in more availability of resources to be allocated for defense?, (ii) does the variation in resource allocation for growth and defense between years of high and low fruiting leads to indirect changes in herbivory? Thirty-five trees located in a Cerrado area were monitored during 2008 (year of high fruiting) and 2009 (year of no fruiting) to evaluate the differential investment in vegetative traits (biomass, growth and number of ramifications), plant defense (tannin concentration and plant hypersensitivity) and herbivory (galling attack and folivory). According to our first question, we observed that in the fruiting year, woody biomass negatively affected tannin concentration, indicating that fruit production restricted the resources that could be invested both in growth as in defense. In the same way, we observed an inter-annual variation in herbivorous attack, and found that plants with higher leaf biomass and tannin concentration, experienced higher galling attack and hypersensitive reaction, regardless years. These findings suggested that plants’ resistance to herbivory is a good proxy of plant defense and an effective defense strategy for C. langsdorffii, besides the evidence of indirect responses of the third trophic level, as postulated by the second question. In summary, the supra-annual fruiting pattern promoted several changes on plant development, demonstrating the importance of evaluating different plant traits when characterizing the vegetative investment. As expected by theory, the trade-off in resource allocation favored changes in defense compounds production and patterns of herbivory. The understanding of this important element of insect-plant interactions will be fundamental to decipher coevolutionary life histories and interactions between plant species reproduction and herbivory. Besides that, only through long-term studies we will be able to build models and develop more accurate forecasts about the factors that trigger the bottom-up effect on herbivory performance, as well the top-down effect of herbivores on plant trait evolution.

Endogenous rhythmic growth, a trait suitable for the study of interplays between multitrophic interactions and tree development

As long-lived organisms, trees use resources to support both growth and below- and aboveground trophic interactions. Resources fluctuate in relation to periods of growth cease that are regulated by internal and external factors, and these fluctuations feed backs to trophic partners. Some major forest trees display an endogenous growth rhythm, and related pulses of variation in allocation of resources have been detected. As this trait makes it possible to separate growth into defined phases, it offers an opportunity to disentangle the intermingled complex regulation of growth and multitrophic interactions in trees. We present “TrophinOak”, a platform using microcuttings of pedunculated oak, a tree that displays endogenous rhythmic growth characterized by alternating shoot and root growth flushes. We select seven beneficial or detrimental above- and belowground partners including animals (Lymantria dispar, Pratylenchus penetrans, Protaphorura armata), fungi (Piloderma croceum, Microsphaera alphitoides, Phytophthora quercina) and bacteria (Streptomyces sp.), to synthesize bi- and tripartite trophic interactions, including ectomycorrhizal symbioses, and monitor fluctuations of carbon and nitrogen allocation as well as plant gene expression at distinct phases of oak growth. We use this model to identify and resolve the experimental challenges inherent in synthesizing diverse types of associations in a common microcosm system, in labeling plants with stable N and C isotopes and in analyzing transcripts in a non-model plant, a process which requires generating a specific contig library. We develop hypotheses and experimental design to test them in order to identify core mechanisms that help trees to modulate their own development and their multitrophic interactions for optimizing their long term performance in their environment. First results constitute a proof of concept that the platform works and enables us to test the hypotheses.

Species Introductions and Their Cascading Impacts on Biotic Interactions in desert riparian ecosystems.

Desert riparian ecosystems of North America are hotspots of biodiversity that support many sensitive species, and are in a region experiencing some of the highest rates of climatic alteration in North America. Fremont cottonwood, Populus fremontii, is a foundation tree species of this critical habitat, but it is threatened by global warming and regional drying, and by a non-native tree/shrub, Tamarix spp., all of which can disrupt the mutualism between P. fremontii and its beneficial mycorrhizal fungal communities. Specialist herbivorous leaf beetles (Diorhabda spp.) introduced for biocontrol of Tamarix are altering the relationship between this shrub and its environment. Repeated episodic feeding on Tamarix foliage by Diorhabda results in varying rates of dieback and mortality, depending on genetic variation in allocation of resources, growing conditions, and phenological synchrony between herbivore and host plant. In this article, we review the complex interaction between climatic change and species introductions and their combined impacts on P. fremontii and their associated communities. We anticipate that (1) certain genotypes of P. fremontii will respond more favorably to the presence of Tamarix and to climatic change due to varying selection pressures to cope with competition and stress; (2) the ongoing evolution of Diorhabda's life cycle timing will continue to facilitate its expansion in North America, and will over time enhance herbivore impact to Tamarix; (3) defoliation by Diorhabda will reduce the negative impact of Tamarix on P. fremontii associations with mycorrhizal fungi; and (4) spatial variability in climate and climatic change will modify the capacity for Tamarix to survive episodic defoliation by Diorhabda, thereby altering the relationship between Tamarix and P. fremontii, and its associated mycorrhizal fungal communities. Given the complex biotic/abiotic interactions outlined in this review, conservation biologists and riparian ecosystem managers should strive to identify and conserve the phenotypic traits that underpin tolerance and resistance to stressors such as climate change and species invasion. Such efforts will greatly enhance conservation restoration efficacy for protecting P. fremontii forests and their associated communities.

Complex genetic effects on early vegetative development shape resource allocation differences between Arabidopsis lyrata populations.

Costs of reproduction due to resource allocation trade-offs have long been recognized as key forces in life history evolution, but little is known about their functional or genetic basis. Arabidopsis lyrata, a perennial relative of the annual model plant A. thaliana with a wide climatic distribution, has populations that are strongly diverged in resource allocation. In this study, we evaluated the genetic and functional basis for variation in resource allocation in a reciprocal transplant experiment, using four A. lyrata populations and F2 progeny from a cross between North Carolina (NC) and Norway parents, which had the most divergent resource allocation patterns. Local alleles at quantitative trait loci (QTL) at a North Carolina field site increased reproductive output while reducing vegetative growth. These QTL had little overlap with flowering date QTL. Structural equation models incorporating QTL genotypes and traits indicated that resource allocation differences result primarily from QTL effects on early vegetative growth patterns, with cascading effects on later vegetative and reproductive development. At a Norway field site, North Carolina alleles at some of the same QTL regions reduced survival and reproductive output components, but these effects were not associated with resource allocation trade-offs in the Norway environment. Our results indicate that resource allocation in perennial plants may involve important adaptive mechanisms largely independent of flowering time. Moreover, the contributions of resource allocation QTL to local adaptation appear to result from their effects on developmental timing and its interaction with environmental constraints, and not from simple models of reproductive costs.

Females Paired with New and Heavy Mates Reduce Intra-Clutch Differences in Resource Allocation

Reproductive investment affects both offspring and parental fitness and influences the evolution of life histories. Females may vary their overall primary reproductive effort in relation to the phenotypic characteristics of their mate. However, the effects of male quality on differential resource allocation within clutches have been largely neglected despite the potential implications for mate choice and population dynamics, especially in species exhibiting biparental care and brood reduction. Female southern rockhopper penguins Eudyptes chrysocome paired with heavy mates reduced intra-clutch variation in egg and albumen masses. Females paired with new mates also reduced intra-clutch variation in yolk androgen levels. Since both an increased mass and increased androgen concentrations positively influence chick survival under sibling competition, the chances of fledging the whole clutch are likely to be higher for newly formed pairs with heavy males than for previously formed pairs with light males. Interestingly, total clutch provisioning did not vary with male quality. We show for the first time that females vary intra-clutch variation in resource allocation according to male quality. In species with brood reduction, it may be more adaptive for females to modulate the distribution of resources within the clutch according to breeding conditions, than to change their total clutch provisioning.

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.

Life history of tundra-dwelling wolf spiders (Araneae: Lycosidae) from the Yukon Territory, Canada

We studied populations of three tundra-dwelling wolf spider (Lycosidae) species to determine reproductive trait relationships and developmental timing in the Arctic. We collected 451 Pardosa lapponica (Thorell, 1872), 176 Pardosa sodalis Holm, 1970, and 117 Pardosa moesta Banks, 1892 during summer 2008. We used log-likelihood ratio tests and multiple linear regressions to determine the best predictors of fecundity and relative reproductive effort. Female body size best explained the variation in fecundity and body condition was the best predictor for relative reproductive effort. We tested for a trade-off between the allocation of resources to individual eggs and the number of eggs produced (fecundity) within each species using linear regression. There was variation in detectable egg size and number trade-offs among sites and these may be related to local variation in resource allocation linked to density-related biotic or abiotic factors. These findings contribute to knowledge about the fitness of arctic wolf spiders in the region of study and are particularly relevant in light of the effects that climate changes are predicted to have on the arctic fauna.

Gender and abiotic stress affect community‐scale intensity of facilitation and its costs

Summary1. Facilitation allows some plant species to occupy environments that they are otherwise unable to inhabit, potentially leading to greater fitness, greater productivity or abundance, and range expansions. However, we know little about the costs incurred by facilitators or how variation in resource allocation by facilitators influences effects and costs.2. Gynodioecy provides an opportunity to explore the effects of facilitation and potential costs because females and hermaphrodites differ in resource allocation patterns. We explored whether environmental stress and gender‐specific facilitation influence species interactions in an alpine plant community. We investigated the degree of facilitation and correlative associated costs for the gynodioecious alpine plant, Silene acaulis, at two elevations (2317 and 2560 m) in the northern Rocky Mountains of Montana, USA.3. Hermaphroditic Silene individuals supported a greater number of plant species and individual plants than female Silene (hermaphrodites = 4.2 ± 0.3, females = 3.5 ± 0.2; hermaphrodites = 11.5 ± 1.0, females = 9.1 ± 1.1). Facilitative effects on species richness significantly increased with elevation (2.1 ± 1.6 species at the low site vs. 3.2 ± 1.8 species at the high site), but abundance and percentage cover did not.4. Silene fitness at the high elevation site (2560 m) was reduced compared to the lower site (2317 m) as measured by flower and seed production. Female flower production decreased by 40%, the number of seeds per fruit by 11.6% and leaf size by 24%.5. Increases in the percentage cover of beneficiaries reduced the number of flowers per Silene plant, indicating a cost of facilitating other species, and this cost was slightly greater for females. However, seed size for hermaphrodites and leaf length for females increased with the percentage cover of beneficiaries, suggesting a mutual benefit of harbouring other species.6. Synthesis. Our results show that gender can affect the balance between competitive and facilitative interactions. Stronger facilitation by hermaphroditic Silene acaulis, coupled with a lower cost of harbouring beneficiaries, suggests that life‐history traits and related patterns of resource allocation can influence the facilitative effects of a species.

Understanding Sex Differences in Human Mortality Rates Through Tinbergen’s Four Questions

Sex differences in human mortality rates emerge from a complex interaction of genetic heritage and developmental environment. Although mortality is not in itself a behavior, it is an indirect product of behavior and physiology and thus responsive to life history variation in resource allocation, behavioral tendencies, and relevant environmental conditions. The explanatory framework of Tinbergenʹs Four Questions is sufficiently powerful in generalization to promote understanding of this phenomenon. Excess male mortality is a result of a trade‐off between competitiveness and longevity. Male life history gives greater emphasis to reproductive effort at the expense of somatic effort, and mating effort at the expense of longevity compared to female life history. Men exhibit riskier behavioral patterns and greater physiological susceptibility, dying at higher rates from behavioral and most non‐behavioral causes across the lifespan. The magnitude of the sex difference in mortality in developed nations peaks when males sexually mature and enter into mating competition. Social and environmental conditions intensifying male competition for resources, status, and mates lead to increased male mortality.

Optimal pollinator attraction strategies in Trollius ranunculoides Hemsl. (Ranunculaceae) at different altitudes: increased floral display or promotion of nectar output?

For alpine plant species, patterns of resource allocation to functional floral traits for pollinator attraction can be highly significant in adaptation to low pollinator abundance and consequent pollen limitation. Increased pollination can be achieved either through a larger floral display or production of more pollen rewards. In this study, variation in resource allocation to different components for pollinator attraction was studied along an altitudinal gradient in Trollius ranunculoides, an obligate self-incompatible out-crosser of the Qinghai-Tibet Plateau. We compared resource allocation to conspicuous yellow sepals (which mainly provide visual attraction) and degenerate petals (which provide the major nectar reward) between populations at four altitudes. Furthermore, we investigated the contribution of sepals and petals to pollinator attraction and female reproductive success in an experiment with sepal or petal removal at sites at different altitudes. At the level of single flowers, resource allocation increased to sepals but decreased to petals with increasing altitude. Consistent with these results, sepals contributed much more to visitation rate and seed set than petals, as confirmed in the sepal or petal removal experiment. Sepals and petals contributed to female reproductive success by ensuring visitation rate rather than visitation duration. To alleviate increasing pollen limitation with increasing altitude, resource allocation patterns of T.ranunculoides altered to favour development of sepals rather than petals. This strategy may improve pollination and reproductive success through visual attraction (sepal) rather than nectar reward (petal) over a gradient of decreasing pollinator abundance.

Differential resource allocation strategies in juvenile elephant seals in the highly seasonal Southern Ocean

Environmental conditions experienced in early life affect growth and influence life his- tory strategies, especially in seasonal environments. We studied the seasonal and sexual variation in resource allocation in juvenile southern elephant seals to investigate whether they show a seasonal decline in growth. We also examined whether sexual differences in growth may lead to separate growth strategies that suit each sex in maximizing fitness. We examined the variation in length (as a measure of somatic growth), body mass and condition of 470 individual 1- to 4-yr-old elephant seals relative to their different growth strategies. Applying a novel growth function, we observed increased somatic growth in summer compared to winter. Males were larger, had higher proportions of lean tissue and grew faster than females, demonstrating the evolution of a male growth strategy of attaining maximum size quickly, and a female strategy of achieving primiparity at an early age. This evidence supports the idea that seasonal patterns reflect seasonal variation in prey availability and quality, and differential growth strategies promote optimal resource allocation and increase an indi- vidual's probability of survival and future breeding success in the highly dynamic and seasonal Southern Ocean.