Influences of multilocus heterozygosity on size during early life

Genetic diversity has been hypothesized to promote fitness of individuals and populations, but few studies have examined how genetic diversity varies with ontogeny. We examined patterns in population and individual genetic diversity and the effect of genetic diversity on individual fitness among life stages (adults and juveniles) and populations of captive yellow perch (Perca flavescens) stocked into two ponds and allowed to spawn naturally. Significant genetic structure developed between adults and offspring in a single generation, even as heterozygosity and allelic richness remained relatively constant. Heterozygosity had no effect on adult growth or survival, but was significantly and consistently positively related to offspring length throughout the first year of life in one pond but not the other. The largest individuals in the pond exhibiting this positive relationship were more outbred than averaged size individuals and also more closely related to one another than they were to average‐sized individuals, suggesting potential heritability of body size or spawn timing effects. These results indicate that the influence of heterozygosity may be mediated through an interaction, likely viability selection, between ontogeny and environment that is most important during early life. In addition, populations may experience significant genetic change within a single generation in captive environments, even when allowed to reproduce naturally. Accounting for the dynamic influences of genetic diversity on early life fitness could lead to improved understanding of recruitment and population dynamics in both wild and captive populations.     

Contrasting heterozygosity‐fitness correlations across life in a long‐lived seabird

Selection is a central force underlying evolutionary change and can vary in strength and direction, for example across time and space. The fitness consequences of individual genetic diversity have often been investigated by testing for multilocus heterozygosity‐fitness correlations (HFCs), but few studies have been able to assess HFCs across life stages and in both sexes. Here, we test for HFCs using a 26‐year longitudinal individual‐based data set from a large population of a long‐lived seabird (the common tern, Sterna hirundo), where 7,974 chicks and breeders of known age were genotyped at 15 microsatellite loci and sampled for life‐history traits over the complete life cycle. Heterozygosity was not correlated with fledging or post‐fledging prospecting probabilities, but was positively correlated with recruitment probability. For breeders, annual survival was not correlated with heterozygosity, but annual fledgling production was negatively correlated with heterozygosity in males and highest in intermediately heterozygous females. The contrasting HFCs among life stages and sexes indicate differential selective processes and emphasize the importance of assessing fitness consequences of traits over complete life histories.     

Heterozygosity–fitness correlations in a wild mammal population: accounting for parental and environmental effects

HFCs (heterozygosity–fitness correlations) measure the direct relationship between an individual's genetic diversity and fitness. The effects of parental heterozygosity and the environment on HFCs are currently under‐researched. We investigated these in a high‐density U.K. population of European badgers (Meles meles), using a multimodel capture–mark–recapture framework and 35 microsatellite loci. We detected interannual variation in first‐year, but not adult, survival probability. Adult females had higher annual survival probabilities than adult males. Cubs with more heterozygous fathers had higher first‐year survival, but only in wetter summers; there was no relationship with individual or maternal heterozygosity. Moist soil conditions enhance badger food supply (earthworms), improving survival. In dryer years, higher indiscriminate mortality rates appear to mask differential heterozygosity‐related survival effects. This paternal interaction was significant in the most supported model; however, the model‐averaged estimate had a relative importance of 0.50 and overlapped zero slightly. First‐year survival probabilities were not correlated with the inbreeding coefficient (f); however, small sample sizes limited the power to detect inbreeding depression. Correlations between individual heterozygosity and inbreeding were weak, in line with published meta‐analyses showing that HFCs tend to be weak. We found support for general rather than local heterozygosity effects on first‐year survival probability, and g2 indicated that our markers had power to detect inbreeding. We emphasize the importance of assessing how environmental stressors can influence the magnitude and direction of HFCs and of considering how parental genetic diversity can affect fitness‐related traits, which could play an important role in the evolution of mate choice.     

Fledgling survival increases with development time and adult survival across north and south temperate zones

Slow life histories are characterized by high adult survival and few offspring, which are thought to allow increased investment per offspring to increase juvenile survival. Consistent with this pattern, south temperate zone birds are commonly longer‐lived and have fewer young than north temperate zone species. However, comparative analyses of juvenile survival, including during the first few weeks of the post‐fledging period when most juvenile mortality occurs, are largely lacking. We combined our measurements of fledgling survival for eight passerines in South Africa with estimates from published studies of 57 north and south temperate zone songbird species to test three predictions: (1) fledgling survival increases with length of development time in the nest; (2) fledgling survival increases with adult survival and reduced brood size controlled for development time; and (3) south temperate zone species, with their higher adult survival and smaller brood sizes, exhibit higher fledgling survival than north temperate zone species controlled for development time. We found that fledgling survival was higher among south temperate zone species and generally increased with development time and adult survival within and between latitudinal regions. Clutch size did not explain additional variation, but was confounded with adult survival. Given the importance of age‐specific mortality to life history evolution, understanding the causes of these geographical patterns of mortality is important.     

Genetic diversity-fitness correlation revealed by microsatellite analyses in European alpine marmots (Marmota marmota)

The relationship between individual genetic diversity and fitness-related traits are poorly understood in the wild. The availability of highly polymorphic molecular markers, such as microsatellites, has made research on this subject more feasible. We used three microsatellite-based measures of genetic diversity, individual heterozygosity H, mean d ² and mean d ² _outbreeding to test for a relationship between individual genetic diversity and important fitness trait, juvenile survival, in a population of alpine marmots (Marmota marmota), after controlling for the effects of ecological, social and physiological parameters that potentially influence juvenile survival in marmots. Analyses were conducted on 158 juveniles, and revealed a positive association between juvenile survival and genetic diversity measured by mean H. No association was found with mean d ² and with mean d ² _outbreeding. This suggests a fitness disadvantage to less heterozygous juveniles. The genetic diversity-fitness correlation (GDFC) was somewhat stronger during years with poor environmental conditions (i.e. wet summers). The stressful environmental conditions of this high mountain population might enhance inbreeding depression and make this association between genetic diversity and fitness detectable. Moreover the mating system, allowing extra pair copulation by occasional immigrants, as well as close inbreeding, favours a wide range of individual genetic diversity (mean H ranges from 0.125 to 1), which also may have facilitated the detection of the GDFC. The results further suggest that the observed GDFC is likely to be explained by the “local effect” hypothesis rather than by the “general effect” hypothesis.     

Heterozygosity and survival in blue tits (Cyanistes caeruleus): contrasting effects of presumably functional and neutral loci

The relationship between genetic diversity and fitness has important implications in evolutionary and conservation biology. This relationship has been widely investigated at the individual level in studies of heterozygosity-fitness correlations (HFC). General effects caused by inbreeding and/or local effects at single loci have been used as explanations of HFC, but the debate about the causes of HFC in open, natural populations is still ongoing. Study designs that control for variation in the inbreeding level of the individuals, and knowledge on the function and location of the markers used to measure heterozygosity, are fundamental to understand the causes of HFC. Here we investigated correlations between individual heterozygosity and estimates of survival at different life-history stages in an open population of blue tits (Cyanistes caeruleus). For survival at the embryo, nestling and fledgling stage, we used a full-sibling approach, i.e. we controlled for the level of inbreeding. We genotyped 1496 individuals with 79 microsatellites mapped across 25 chromosomes in the zebra finch (Taeniopygia guttata) that were classified either as potentially functional (58 loci) or as neutral (21 loci). We found different effects of standardized multilocus heterozygosity (SH): SH(functional) had a negative effect on the probability of hatching and local recruitment of females, whereas SH(neutral) had a positive effect on adult survival. The negative effects of functional loci are better explained by local effects, whereas the positive effects of neutral markers could reflect inbreeding effects in the population. Our results highlight the importance of considering the characteristics of the markers used in HFC studies and confirm the mixed effects of heterozygosity in different contexts (e.g. sex and life-history stage).     

Sex-Specific Correlations of Individual Heterozygosity,Parasite Load,and Scalation Asymmetry in a Sexually Dichromatic Lizard

Heterozygosity-fitness correlations (HFCs) provide insights into the genetic bases of individual fitness variation in natural populations. However, despite decades of study, the biological significance of HFCs is still under debate. In this study, we investigated HFCs in a large population of the sexually dimorphic lizard Takydromus viridipunctatus (Lacertidae). Because of the high prevalence of parasitism from trombiculid mites in this lizard, we expect individual fitness (i.e., survival) to decrease with increasing parasite load. Furthermore, because morphological asymmetry is likely to influence individuals'' mobility (i.e., limb asymmetry) and male biting ability during copulation (i.e., head asymmetry) in this species, we also hypothesize that individual fitness should decrease with increasing morphological asymmetry. Although we did not formally test the relationship between morphological asymmetry and fitness in this lizard, we demonstrated that survival decreased with increasing parasite load using a capture-mark-recapture data set. We used a separate sample of 140 lizards to test the correlations between individual heterozygosity (i.e., standardized mean d² and HL based on 10 microsatellite loci) and the two fitness traits (i.e., parasite load and morphological asymmetry). We also evaluated and excluded the possibility that single-locus effects produced spurious HFCs. Our results suggest male-only, negative correlations between individual heterozygosity and parasite load and between individual heterozygosity and asymmetry, suggesting sex-specific, positive HFCs. Male T. viridipunctatus with higher heterozygosity tend to have lower parasite loads (i.e., higher survival) and lower asymmetry, providing a rare example of HFC in reptiles.     

The strength of the association between heterozygosity and probability of interannual local recruitment increases with environmental harshness in blue tits

The extent of inbreeding depression and the magnitude of heterozygosity–fitness correlations (HFC) have been suggested to depend on the environmental context in which they are assayed, but little evidence is available for wild populations. We combine extensive molecular and capture–mark–recapture data from a blue tit (Cyanistes caeruleus) population to (1) analyze the relationship between heterozygosity and probability of interannual adult local recruitment and (2) test whether environmental stress imposed by physiologically suboptimal temperatures and rainfall influence the magnitude of HFC. To address these questions, we used two different arrays of microsatellite markers: 14 loci classified as neutral and 12 loci classified as putatively functional. We found significant relationships between heterozygosity and probability of interannual local recruitment that were most likely explained by variation in genomewide heterozygosity. The strength of the association between heterozygosity and probability of interannual local recruitment was positively associated with annual accumulated precipitation. Annual mean heterozygosity increased over time, which may have resulted from an overall positive selection on heterozygosity over the course of the study period. Finally, neutral and putatively functional loci showed similar trends, but the former had stronger effect sizes and seemed to better reflect genomewide heterozygosity. Overall, our results show that HFC can be context dependent, emphasizing the need to consider the role of environmental heterogeneity as a key factor when exploring the consequences of individual genetic diversity on fitness in natural populations.     

Increased lifetime reproductive success of first‐hatched siblings in Common Kestrels Falco tinnunculus

Order of birth has profound consequences on offspring across taxa during development and can have effects on individuals later in life. In birds, differential maternal allocation and investment in their progeny lead to variance in the environmental conditions that offspring experience during growth within the brood. In particular, laying and hatching order have been proposed to influence individual quality during the growing period, but little is known about the fitness consequences that these two factors have for offspring from a lifetime perspective. We explored the effect of laying and hatching order on post‐fledgling survival (measured as recruitment probability) and lifetime reproductive success (LRS) in Common Kestrels Falco tinnunculus, using a long‐term and individual‐based dataset. First‐hatched chicks showed higher survival probability and LRS than their siblings. This effect was not due to body condition of the individuals at adulthood, the quality of their mates or the reproductive outcome compared with later‐hatched individuals. Instead, first‐hatched chicks had a higher recruitment probability. This could be explained by the higher body condition attained by first‐hatched chicks at the end of the nesting period, perhaps due to an enhanced competitive advantage for food over their siblings at the time of hatching. Laying order, in contrast to hatching order, appeared to have little or no effect on LRS. Our results suggest that hatching order within siblings predicts fitness, and that better early‐life conditions during growth experienced by first‐hatched chicks improve first survival and then recruitment, resulting in an enhanced LRS.     

Heterozygosity–behavior and heterozygosity–fitness correlations in a salamander with limited dispersal

Inbreeding and genetic drift can decrease genetic heterozygosity, and this low heterozygosity can depress fitness, resulting in heterozygosity–fitness correlations (HFCs). HFCs are typically small in magnitude, a result often attributed to power of the analyses. Animal behaviors often affect fitness and are often heritable to some degree. We hypothesized that heterozygosity influences behavior, which, in turn, potentially influences fitness. Specifically, in red-backed salamanders, Plethodon cinereus, which have limited dispersal and the potential for inbreeding, we tested whether heterozygosity, as estimated from six microsatellite loci, affected home range size, juvenile growth, and survival. We found that salamanders with higher heterozygosity had larger home ranges and grew faster, which is indicative of reproductive success. However, we found no effects of heterozygosity on survival. We conclude that, because activity in P. cinereus is tightly linked to food uptake and mass gain, heterozygosity influences growth via effects on foraging behavior. Future research should investigate how the relationship between heterozygosity, behavior, and fitness may be affected or mediated by endocrine or immune systems.     

Unexpected positive and negative effects of continuing inbreeding in one of the world's most inbred wild animals

Inbreeding depression, the reduced fitness of offspring of related individuals, is a central theme in evolutionary biology. Inbreeding effects are influenced by the genetic makeup of a population, which is driven by any history of genetic bottlenecks and genetic drift. The Chatham Island black robin represents a case of extreme inbreeding following two severe population bottlenecks. We tested whether inbreeding measured by a 20‐year pedigree predicted variation in fitness among individuals, despite the high mean level of inbreeding and low genetic diversity in this species. We found that paternal and maternal inbreeding reduced fledgling survival and individual inbreeding reduced juvenile survival, indicating that inbreeding depression affects even this highly inbred population. Close inbreeding also reduced survival for fledglings with less‐inbred mothers, but unexpectedly improved survival for fledglings with highly inbred mothers. This counterintuitive interaction could not be explained by various potentially confounding variables. We propose a genetic mechanism, whereby a highly inbred chick with a highly inbred parent inherits a “proven” genotype and thus experiences a fitness advantage, which could explain the interaction. The positive and negative effects we found emphasize that continuing inbreeding can have important effects on individual fitness, even in populations that are already highly inbred.     

Age-specific effect of heterozygosity on survival in alpine marmots, Marmota marmota

The fitness consequences of heterozygosity and the mechanisms underpinning them are still highly controversial. Using capture–mark–recapture models, we investigated the effects of individual heterozygosity, measured at 16 microsatellite markers, on age-dependent survival and access to dominance in a socially monogamous mammalian species, the alpine marmot. We found a positive correlation between standardized multilocus heterozygosity and juvenile survival. However, there was no correlation between standardized multilocus heterozygosity and either survival of older individuals or access to dominance. The disappearance of a significant heterozygosity fitness correlation when individuals older than juveniles are considered is consistent with the prediction that differences in survival among individuals are maximal early in life. The lack of a correlation between heterozygosity and access to dominance may be a consequence of few homozygous individuals attaining the age at which they might reach dominance. Two hypotheses have been proposed to explain heterozygosity-fitness correlations: genome-wide effects reflected by all markers or local effects of specific markers linked to genes that determine fitness. In accordance with genome-wide effects of heterozygosity, we found significant correlations between heterozygosities calculated across single locus or across two sets of eight loci. Thus, the genome-wide heterozygosity effect seems to explain the observed heterozygosity-fitness correlation in the alpine marmot.     

Lifetime fitness correlates of natal dispersal distance in a colonial bird

1. Obtaining empirical evidence of the consequences of dispersal distance on fitness is challenging in wild animals because long-term, unbiased data on reproduction, survival and movement are notoriously difficult to obtain. 2. Lifetime fitness correlates of natal dispersal distance were studied in an isolated population of the facultatively colonial lesser kestrel Falco naumanni (Fleischer) monitored during 8 years at north-eastern Spain, where most birds (83%) dispersed from their natal colony to settle at distances ranging from 112 m to 136.5 km. 3. Neither annual breeding success nor age at recruitment was affected by natal dispersal distance. However, a capture-mark-recapture analysis revealed that survival during the year following recruitment decreased exponentially with dispersal distance, with differences of up to 15% between philopatrics and long-distance dispersers. In subsequent years, it remained similar irrespective of the natal dispersal distance moved. These results did not seem to be biased by long-distance dispersers settling differentially in the periphery of the population (which could emigrate permanently and be considered dead in future occasions) or within-individual consistency in successive dispersal distances, so our results appear to reflect genuine survival differences between dispersal tactics. 4. Average lifetime fledgling production, average lifetime recruitment success and rate-sensitive individual fitness (λ(ind)) also decreased with the distance from the natal to the first-breeding colony, indicating that dispersal decisions early in life affecting immediate survival prospects may translate into long-term fitness costs. 5. Both survival and lifetime fitness models including continuous dispersal distances significantly improved the characterization of the effect on fitness compared with models considering dispersal as a discrete process (i.e. dispersal vs. philopatry at a colony level). 6. Long-distance dispersers were more likely to establish new colonies regardless of whether they recruited in the centre or the periphery of the population, revealing their important role in the colonization of unoccupied patches. Individuals experienced a higher probability of mortality in small and newly funded colonies, so lifetime fitness costs of dispersal seem to be explained by recruitment in sites where average quality is low because of high uncertainty in survival prospects.     

HETEROZYGOSITY-FITNESS CORRELATIONS REVEALED BY NEUTRAL AND CANDIDATE GENE MARKERS IN ROE DEER FROM A LONG-TERM STUDY

Heterozygosity-fitness correlations (HFCs) are increasingly reported but the underlying mechanisms causing HFCs are generally poorly understood. Here, we test for HFCs in roe deer ( Capreolus capreolus ) using 22 neutral microsatellites widely distributed in the genome and four microsatellites in genes that are potentially under selection. Juvenile survival was used as a proxy for individual fitness in a population that has been intensively studied for 30 years in northeastern France. For 222 juveniles, we computed two measures of genetic diversity: individual heterozygosity ( H ), and mean d ² (relatedness of parental genomes). We found a relationship between genetic diversity and fitness both for the 22 neutral markers and two candidate genes: IGF1 (Insulin-like Growth Factor I) and NRAMP (natural resistance-associated macrophage protein). Statistical evidence and the size of genetic effects on juvenile survival were comparable to those reported for early development and cohort variation, suggesting a substantial influence of genetic components on fitness in this roe deer population. For the 22 neutral microsatellites, a correlation with fitness was revealed for mean d ², but not for H , suggesting a possible outbreeding advantage. This heterosis effect could have been favored by introduction of genetically distant (Hungarian) roe deer to the population in recent times and, possibly, by the structuring of the population into distinct clans. The locus-specific correlations with fitness may be driven by growth rate advantages and resistance to diseases known to exist in the studied population. Our analyses of neutral and candidate gene markers both suggest that the observed HFCs are likely mainly due to linkage with dominant or overdominant loci that affect fitness ("local" effect) rather than to a genome-wide relationship with homozygosity due to inbreeding ("general" effect).     

Phenotypic selection and covariation in the life‐history traits of elephant seals: heavier offspring gain a double selective advantage

Early developmental conditions contribute to individual heterogeneity of both phenotypic traits and fitness components, ultimately affecting population dynamics. Although the demographic consequences of ontogenic growth are best quantified using an integrated measure of fitness, most analyses to date have instead studied individual fitness components in isolation. Here, we estimated phenotypic selection on weaning mass in female southern elephant seals Mirounga leonina by analyzing individual‐based data collected between 1986 and 2016 with capture–recapture and matrix projection models. In support of a hypothesis predicting a gradual decrease of weaning mass effects with time since weaning (the replacement hypothesis), we found that the estimated effects of weaning mass on future survival and recruitment probability was of intermediate duration (rather than transient or permanent). Heavier female offspring had improved odds of survival in early life and a higher probability to recruit at an early age. The positive link between weaning mass and recruitment age is noteworthy, considering that pre‐recruitment mortality already imposed a strong selective filter on the population, leaving only the most ‘robust’ individuals to reproduce. The selection gradient on asymptotic population growth rate, a measure of mean absolute fitness, was weaker than selection on first‐year survival and recruitment probabilities. Weaker selection on mean fitness occurs because weaning mass has little impact on adult survival, the fitness component to which the population growth of long‐lived species is most sensitive. These results highlight the need to interpret individual variation in phenotypic traits in a context that considers the demographic pathways between the trait and an inclusive proxy of individual fitness. Although variation in weaning mass do not translate to permanent survival differences among individuals in adulthood, it explains heterogeneity and positive covariation between survival and breeding in early life, which contribute to between‐individual variation in fitness.     

INBREEDING INFLUENCES WITHIN‐BROOD HETEROZYGOSITY‐FITNESS CORRELATIONS (HFCS) IN AN ISOLATED PASSERINE POPULATION

Molecular estimates of inbreeding may be made using genetic markers such as microsatellites, however the interpretation of resulting heterozygosity‐fitness correlations (HFCs) with respect to inbreeding depression is not straightforward. We investigated the relationship between pedigree‐determined inbreeding coefficients (f) and HFCs in a closely monitored, reintroduced population of Stewart Island robins (Petroica australis rakiura) on Ulva Island, New Zealand. Using a full sibling design, we focused on differences in juvenile survival associated specifically with individual sibling variation in standardized multilocus heterozygosity (SH) when expected f was identical. We found that within broods, siblings with higher SH at microsatellite loci experienced a higher probability of juvenile survival. This effect, however, was detected primarily within broods that experienced inbreeding or when inbreeding had occurred in their pedigree histories (i.e., at the parents’ level). Thus we show, for the first time in a wild population, that the strength of an HFC is partially dependent on the presence of inbreeding events in the recent pedigree history. Our results illustrate the importance of realized effects of inbreeding on genetic variation and fitness and the value of full‐sibling designs for the study of HFCs in the context of small, inbred populations.     

Female genetic heterogeneity affects the reproduction of great tits (Parus major L., 1758) in low-quality woodlands

Genetic heterogeneity is considered an important parameter for individual fitness and reproductive success. In 1999 and 2000, we studied the population genetics of great tit ( Parus major L., 1758) in southwestern Germany from two different forest types (deciduous and mixed-coniferous), which may significantly differ in prey diversity and/or food supply. Adults of 99 families were genotyped at four enzyme and eight microsatellite loci, in order to estimate individual heterozygosity. In the mixed-coniferous forest, a significant positive correlation between the genetic heterogeneity of females and early egg-laying date and clutch size was detected. Early egg-laying date and increased clutch size are conditions that positively affect the number of fledglings. This effect of individual heterozygosity was not observed in the deciduous woodland. Maternal genetic heterogeneity, however, did not correlate with fledgling condition, and individual heterozygosity of fathers had no impact on breeding success in either habitat. The positive effect of female genetic heterogeneity on brood size of great tits in mixed-coniferous forests is attributed to early egg-laying date, i.e. a maternal effect, rather than to a specific mating strategy that optimizes fitness through an increased brood size and the quality of offspring.     

Genetic diversity at neutral and adaptive loci determines individual fitness in a long-lived territorial bird

There is compelling evidence about the manifest effects of inbreeding depression on individual fitness and populations' risk of extinction. The majority of studies addressing inbreeding depression on wild populations are generally based on indirect measures of inbreeding using neutral markers. However, the study of functional loci, such as genes of the major histocompatibility complex (MHC), is highly recommended. MHC genes constitute an essential component of the immune system of individuals, which is directly related to individual fitness and survival. In this study, we analyse heterozygosity fitness correlations of neutral and adaptive genetic variation (22 microsatellite loci and two loci of the MHC class II, respectively) with the age of recruitment and breeding success of a decimated and geographically isolated population of a long-lived territorial vulture. Our results indicate a negative correlation between neutral genetic diversity and age of recruitment, suggesting that inbreeding may be delaying reproduction. We also found a positive correlation between functional (MHC) genetic diversity and breeding success, together with a specific positive effect of the most frequent pair of cosegregating MHC alleles in the population. Globally, our findings demonstrate that genetic depauperation in small populations has a negative impact on the individual fitness, thus increasing the populations' extinction risk.     

The effect of maternal glucocorticoid levels on juvenile docility in yellow-bellied marmots

Maternal effects can have significant and long-term consequences on offspring behavior and survival, while consistent individual differences (i.e., personality) can have profound impacts on individual fitness. Thus, both can influence population dynamics. However, the underlying mechanisms that determine variation in personality traits are poorly understood. Maternal effects are one potential mechanism that may explain personality variation. We capitalized on a long-term study of yellow-bellied marmots (Marmota flaviventris) to identify maternal effects on juvenile docility. To do so, we partitioned the variance in juvenile docility using a quantitative genetic modeling approach to isolate potential maternal effects. We also directly tested whether maternal stress, measured through fecal glucocorticoid metabolite levels during lactation of 82 mothers, was associated with offspring docility. Docility scores were estimated for 645 juveniles trapped between 2002 and 2012. We found an interaction between maternal glucocorticoid levels and dam age on juvenile docility. We also found significant maternal, litter, permanent environment, and year effects. These results suggest that a mother's life history stage interacts with stress to influence offspring personality. This early life influence can have long lasting effects on an individual's docility throughout life.     

Age‐dependent,negative heterozygosity–fitness correlations and local effects in an endangered Caribbean reptile,Iguana delicatissima

Inbreeding depression can have alarming impacts on threatened species with small population sizes. Assessing inbreeding has therefore become an important focus of conservation research. In this study, heterozygosity–fitness correlations (HFCs) were measured by genotyping 7 loci in 83 adult and 184 hatchling Lesser Antillean Iguanas, Iguana delicatissima, at a communal nesting site in Dominica to assess the role of inbreeding depression on hatchling fitness and recruitment to the adult population in this endangered species. We found insignificant correlations between multilocus heterozygosity and multiple fitness proxies in hatchlings and adults. Further, multilocus heterozygosity did not differ significantly between hatchlings and adults, which suggests that the survivorship of homozygous hatchlings does not differ markedly from that of their heterozygous counterparts. However, genotypes at two individual loci were correlated with hatching date, a finding consistent with the linkage between specific marker loci and segregating deleterious recessive alleles. These results provide only modest evidence that inbreeding depression influences the population dynamics of I. delicatissima on Dominica.