Individual Reproductive Success Research Articles

Winter madness: Melatonin as a neuroendocrine regulator of seasonal aggression.

Individuals of virtually all vertebrate species are exposed to annual fluctuations in the deterioration and renewal of their environments. As such, organisms have evolved to restrict energetically expensive processes and activities to a specific time of the year. Thus, the precise timing of physiology and behavior is critical for individual reproductive success and subsequent fitness. Although the majority of research on seasonality has focused on seasonal reproduction, pronounced fluctuations in other non-reproductive social behaviors, including agonistic behaviors (e.g., aggression), also occur. To date, most studies that have investigated the neuroendocrine mechanisms underlying seasonal aggression have focused on the role of photoperiod (i.e., day length); prior findings have demonstrated that some seasonally breeding species housed in short "winter-like" photoperiods display increased aggression compared with those housed in long "summer-like" photoperiods, despite inhibited reproduction and low gonadal steroid levels. While fewer studies have examined how the hormonal correlates of environmental cues regulate seasonal aggression, our previous work suggests that the pineal hormone melatonin acts to increase non-breeding aggression in Siberian hamsters (Phodopus sungorus) by altering steroid hormone secretion. This review addresses the physiological and cellular mechanisms underlying seasonal plasticity in aggressive and non-aggressive social behaviors, including a key role for melatonin in facilitating a "neuroendocrine switch" to alternative physiological mechanisms of aggression across the annual cycle. Collectively, these studies highlight novel and important mechanisms by which melatonin regulates aggressive behavior in vertebrates and provide a more comprehensive understanding of the neuroendocrine bases of seasonal social behaviors broadly.

Effects of Supplementation in Upper Yakima River Chinook Salmon

AbstractTo promote recovery of natural salmonid populations, managers are utilizing hatchery supplementation programs to increase abundance of spawners on the spawning grounds. However, studies have provided evidence that captive breeding can result in domestication, demonstrated by lower fitness of hatchery‐origin compared with natural‐origin fish. Supplementation programs, therefore, typically use natural‐origin broodstock in an effort to minimize long‐term negative fitness impacts. Here we evaluated the upper Yakima River spring supplementation program for Chinook Salmon Oncorhynchus tshawytscha, which has broodstock comprised exclusively of unmarked fish presumed to be of natural‐origin. Using 5 years of spawner data, we tested for effects of hatchery breeding and rearing on total adult returns and their individual reproductive success when spawning naturally. Our study revealed that supplementation increased overall abundance of fish spawning naturally on the spawning grounds. However, on average, compared with natural‐origin spawners, hatchery‐origin fish had reduced reproductive success, which also translated to reduced reproductive success in three out of five return years for natural‐origin fish that spawned with hatchery‐origin fish. As expected, body length and return timing were also significant predictors of reproductive success. However, more generations of data are needed to establish the extent to which reduced reproductive success is passed on to naturally produced progeny.

High pollen immigration but no gene flow via-seed into a Genetic Conservation Unit of the endangered Picea omorika after disturbance

Studying how genetic diversity is transmitted between generations is critical for assessing the survival prospects of fragmented forest tree populations. This is especially urgent in the case of rare, endangered species that are at high risk of extinction and/or exceptionally susceptible to climate change, and are thus to be prioritised for conservation initiatives. We performed the first assessment of gene flow patterns by parentage analysis in the IUCN red-listed Serbian spruce [Picea omorika (Panč.) Purk.], within a Genetic Conservation Unit (GCU) which was exposed to fire disturbance 30 years ago. Parentage analysis was based on assigning the parentage of 104 juveniles to all the adult trees (48) present in the 2.8 ha population. All individuals were genotyped at 11 highly informative nuclear microsatellite markers.We found that fire disturbance triggered natural regeneration, usually poor to absent in Serbian spruce, and boosted pollen immigration (66%), which is reported as rather modest among undisturbed populations of this species. Seed immigration was absent, coherently with what was previously hypothesised for natural, undisturbed populations. Thus, the immigration of new gametes into the studied Serbian spruce population was accomplished exclusively through pollen gene flow, at a rate sufficient to counteract, at least in the short term, genetic drift. Furthermore, the abundant post-disturbance pollen immigration most likely accounts for the lack of fine-scale spatial genetic structure (SGS) in the juvenile cohort, contrary to the SGS observed in the adult cohort which is amongst the strongest ever recorded in anemophilous forest tree species. Finally, as generally found in forest trees, individual reproductive success was uneven among individuals, with 25% of local adults siring 70% of the sampled juveniles.Our results on post-disturbance gene flow patterns in the only Serbian spruce population with reportedly abundant regeneration complement the outcomes of previous genetic studies while providing essential information for the dynamic management and conservation of this rare and endangered species severely threatened by climate warming. Tracking the temporal development of gene flow parameters and the consequences of gene flow on genetic diversity are two cornerstones of future forest genetic monitoring programs, which are particularly important for GCUs. In particular, monitoring the genetic diversity of forest regeneration is deemed as the key for understanding changes that otherwise would remain mostly untraceable in long-lived organisms such as forest trees.

Acclimation of elk mating system following restoration to the Missouri Ozarks, U.S.A.

Biologists increasingly use translocation to restore animals to areas where they have been extirpated. However, we know little about how translocation decisions influence translocation‐mediated social dynamics. Breeding in polygynous ungulate mating systems is typically dominated by prime age males, but founding males within translocated ungulate populations often are comprised of only young individuals. We investigated the influence of releasing exclusively young‐aged males on mating system and male reproductive success during an elk (Cervus canadensis) restoration program in Missouri. From 2011 to 2013, we translocated and released 106 elk from Kentucky to Missouri, U.S.A. We collected tissue samples for DNA from all translocated elk and subsequently captured adults and calves in Missouri during 2014–2018 for paternity analysis. Initial levels of polygyny were low but increased and acclimated over the initial years following translocation, commensurate with advancing sire age structure and increasing population density. Sire age was positively associated with individual male reproductive success initially, but the effect of age decreased as polygyny acclimated and sire age structure became older and more variable. Polygyny levels in the reintroduced population were restored to expected values within 4 years of the last translocation event, demonstrating the acclimation of mating structure despite a translocation tactic favoring young‐aged males. Importantly, initial dampened polygyny may facilitate retention of genetic variation by maximizing the genetic contribution of more founding individuals; however, benefits to genetic variation retention should be considered against potential demographic consequences to calves sired by young males.

High egg retention in Chinook Salmon Oncorhynchus tshawytscha carcasses sampled downstream of a migratory barrier.

Barriers in rivers have the potential to severely decrease functional connectivity between habitats. Failure to pass barriers and reach natal spawning habitat may compromise individual reproductive success, particularly for semelparous, philopatric species that rely on free-flowing rivers to reach natal habitat during their once-in-a-lifetime spawning migrations. To investigate the consequences of in-river barriers on fish spawning success, we quantified egg retention and spawning effort (caudal fin wear) in female Chinook Salmon Oncorhynchus tshawytscha carcasses collected downstream of the Whitehorse Hydro Plant on the upper Yukon River and at a nearby free-flowing tributary (Teslin River) from 2018 to 2020 (~2900 km migrations). Previous studies have demonstrated that a large proportion of fish attempting to reach spawning locations upstream of the hydro plant fail to pass the associated fishway. We estimated nearly all female salmon failing to pass the hydro plant attempted spawning in non-natal habitat downstream, but that these females retained ~34% of their total fecundity compared to ~6% in females from the free-flowing river. Females downstream of the hydro plant also had lower wear on their caudal fin, a characteristic that was correlated with increased egg deposition. Egg retention did not vary across years with different run sizes, and we propose that egg retention downstream of the hydro plant was not driven by density-dependent mechanisms. Findings from this work indicate that female Chinook Salmon can still deposit eggs following failed fish passage and failure to reach natal spawning sites, though egg retention rates are considerably higher and uncertainties remain about reproductive success. We encourage researchers to incorporate carcass surveys into fish passage evaluations for semelparous species to fully account for consequences of failed passage.

Heat Wave Intensity Drives Sublethal Reproductive Costs in a Tidepool Copepod.

SynopsisPhysiological stress may induce sublethal effects on fitness by limiting energy availability and shifting energy allocation, which can incur reproductive costs. Sublethal reproductive costs may affect vital rates, linking stress events such as heat waves to population demography. Here, we test the hypothesis that heat wave intensity and consecutive days of exposure to heat wave temperatures impact survival and individual reproductive success. We subjected groups of the marine harpacticoid copepod, Tigriopus californicus, to 6 heat wave regimes that differed in maximum exposure temperature, 26°C or 32°C, and number of consecutive exposure days (1, 2, or 7), and predicted that survival and reproductive costs would increase with heat wave intensity and duration. We measured individual survival and offspring production during the heat waves and for 2 weeks following the last day of each experimental heat wave. Despite similar survivorship between the 2 maximum temperature treatments, sublethal effects of heat wave intensity were observed. Consistent with our predictions, individuals that experienced the higher maximum temperature 32°C heat waves produced fewer offspring overall than those that experienced the 26°C heat wave. Furthermore, the number of naupliar larvae (nauplii) per clutch was lower in the 32°C group for egg clutches produced immediately after the final day of exposure. Our results are consistent with the hypothesis that increasing thermal stress can lead to sublethal costs, even with no discernible effects on mortality. Heat waves may not always have lethal effects on individuals, especially for individuals that are adapted to routine exposures to high temperatures, such as those occupying the high intertidal. Costs, however, associated with stress and/or reduced performance due to non-linearities, can affect short-term demographic rates. The effect of these short-term sublethal perturbations is needed to fully understand the potential for population rescue and evolution in the face of rapid climate change.

Steroid hormones in hair and fresh wounds reveal sex specific costs of reproductive engagement and reproductive success in wild house mice (Mus musculus domesticus)

Not only males but also females compete over reproduction. In a population of free-living house mice (Mus musculus domesticus), we analyzed how (metabolic) costs of aggressive interactions (reflected in fresh wounds and long-term corticosterone concentrations in hair) are predicted by individual reproductive physiology and reproductive success in males and females. Over eight years, we studied wounds and reproduction of more than 2800 adults under naturally varying environmental conditions and analyzed steroid hormones from more than 1000 hair samples. Hair corticosterone were higher and wounds more frequent in males than females. In males, wound occurrence increased with increasing breeding activity in the population, without affecting hair corticosterone levels. Unexpectedly, individual male reproductive success did not predict wounds, while hair corticosterone increased with increasing levels of hair testosterone and reproductive success. High corticosterone in hair of males might therefore reflect metabolic costs of fighting over reproduction. In females, hair corticosterone was generally lower than in males and high levels did not impede pregnancy. Reproductive investment (reflected in hair progesterone) was dissociated from reproductive success. Occasional wounds in females indicated individuals without recent reproductive success and revealed reproductive competition, presumably driven by instability in the social environment. In both sexes, corticosterone increased with age, but there was no evidence that received overt aggression, as indicated by wounds or elevated corticosterone, suppressed reproductive physiology. Our results diverge from laboratory findings and emphasize the need to also study animals in their natural environment in order to understand the complexity of their behavioral physiology.

Helpers during replacement clutches buffer the impacts of late breeding on a cooperative bird

Renesting is an important strategy employed by many bird species to compensate for nest failure. However, although replacement clutches may increase an individual's annual reproductive success, they impose substantial energetic and fitness costs. In some cooperatively breeding species, helpers lighten breeders' workloads thereby facilitating a second clutch within a season or increasing their survival prospects. Alternatively, renesting may increase the chances of having help in replacement clutches as some individuals that have lost their own clutch could redirect their parental effort to another nest. Here we used a 20-year dataset of a facultative cooperative breeder, the Iberian magpie, Cyanopica cooki , to investigate how helping and renesting behaviours combine to affect reproductive output. After controlling for clutch size and laying date, we show that helpers had a positive effect on the reproductive success of pairs, particularly in replacement clutches. Indeed, our study revealed that replacement clutches were much more common than previously thought (observed in three-quarters of the females that lost the first clutch), and that the probability of receiving help was higher in replacement clutches. As helpers increased in number over the breeding season, they could contribute to buffering the negative effects of breeding late, when environmental conditions can be more adverse, and the probability of successful independent reproduction is lower. This study indicates that species with cooperative breeding and a short lifespan can prioritize current over future reproduction by renesting at the end of the breeding season, when the benefits of having help outweigh the costs associated with deteriorating environmental conditions. We propose that renesting can be a context-dependent strategy (mediated by social and environmental factors) that may increase reproductive success in avian cooperative breeding systems. • Renesting is an important context-dependent strategy in Iberian magpies. • Probability of receiving help is higher in replacement than in first clutches. • Helpers increase reproductive success, but more so in replacement clutches. • Helpers thus contribute to buffer the negative effects of late breeding.

Could the reproductive system explain the stability and long-term persistence in a natural hybrid zone of Petunia (Solanaceae)?

The long-term success of populations is dependent on individual reproductive success, and in general, increased population size and genetic diversity contribute to population maintenance, reducing the risk of local extinction. Interspecific hybridization has consequences that can vary according to the hybrids' fate, which can be strongly influenced by the reproductive capacity of hybrids and canonical individuals from the contact zone. We examined the reproductive biology and morphology of two closely related Petunia (Solanaceae) species and their interspecific hybrids from Serra do Sudeste, Southern Brazil, and we measured their reproductive success under controlled conditions based on seed production and germination from five pollination treatments. We found differences in self-compatibility degree among individuals, lineages, and pollination treatments based on high total seed production (> 204,000 seeds) and germination (630 seedlings evaluated). No correlation was observed between corolla colour and reproductive success or between floral morphological traits and compatibility. High self-compatibility and inter-lineage compatibility can explain the hybrid populations' maintenance and origin, favouring the two analysed species' introgression.

Space use and parental care behaviour in Andinobates claudiae (Dendrobatidae)

Abstract The selection of habitats with potential reproductive resources may maximize individual reproductive success and overall fitness. Dendrobatid frogs display remarkable parental care which is associated with water bodies (phytotelmata) contained in plants with characteristics that are important to offspring survival. It has been shown that the size of phytotelmata is a key factor that drove the divergence in parental care patterns in poison frogs and that the distribution of reproductive resources can influence space use in these species. Here, we investigated parental care strategies and the influence of reproductive resource distribution on space use patterns in a wild population of Andinobates claudiae in Bocas del Toro, Panama. We identified the phytotelmata characteristics that predict tadpole deposition and analysed the association between the spatial distribution of phytotelmata and spatial use of males and females. Our observations showed that this species mates polygamously and exhibits male parental care. We found that male frogs have smaller kernel density home ranges and core areas compared to females, and that space use is related to the density of Heliconia plants whose axil cavities are used for tadpole rearing. Furthermore, we found that tadpoles were more frequently found in phytotelmata that were at lower heights and contained larger water volumes. Fathers invested time inspecting multiple cavities and travelled further than predicted from their territories to find suitable deposition sites. Our observations suggest a selective choice of phytotelmata regarding tadpole deposition, where distribution and quality of cavities might influence parental care decisions.

Close‐kin methods to estimate census size and effective population size

AbstractThe last two decades have witnessed rapid developments and increasing interest in use of: (1) genetic methods to estimate effective population size (Ne) and (2) close‐kin mark–recapture (CKMR) methods to estimate abundance based on the incidence of close relatives. WhereasNeestimation methods have been applied to a wide range of taxa, all CKMR applications to date have been for aquatic species. These two fields of inquiry have developed largely independently, and this is unfortunate because deeper insights can be gained by joint evaluation of eco‐evolutionary processes. In this synthesis, we use simple analytical models and simulated pedigree data to illustrate how various factors (life‐history traits; patterns of variation in individual reproductive success; experimental design; stochasticity; marker type) can affect the performance of the estimators. We show that theNe/Nratio and the probability of a close‐kin match both depend on a vector of parental weights that specify relative probabilities that different individuals will produce offspring. Although age‐specific vital rates are central to both methodologies, for CKMR they can potentially bias abundance estimates unless properly accounted for, whereas they represent the signals of genetic drift thatNeestimation methods depend upon. CoordinatingNeand CKMR estimation methods using the same or overlapping datasets would facilitate joint evaluation of both the ecological and evolutionary consequences of abundance.

Morphological changes and reproductive costs in brooders of two mouthbrooding freshwater fishes

AbstractParental care purportedly promotes individual reproductive success and improves offspring survival, but is thought to come at a cost to the adult carer. Reproductive costs can be physiological such as the resources parents spend on caring but also the morphological changes that are necessary to accomplish parental care activities. This study considers morphological and body condition changes in brooders of two paternal mouthbrooder fishes – which incubate eggs and guard young inside the buccal cavity – mouth almighty (Glossamia aprion) and blue catfish (Neoarius graeffei), from rivers of northern Australia. Potential costs associated with mouthbrooding were examined by quantifying body condition, feeding deterrence and changes in gut length and gill form across individuals from varying sex‐breeding state category (brooder males, nonbrooder males and females). Brooders of both species exhibited significantly lower values in some condition indices, and did not feed, suggesting that body reserves were being used and not renewed during mouthbrooding. Brooders of both species had shorter gut lengths than nonbrooders, potentially to reduce tissue maintenance costs during a time of restricted food intake and requirements. Both species also exhibited changes in gill form and structure compared to nonbrooders; indicating structural adaptive plasticity to mouthbrooding by allowing more space for egg brooding in the buccal cavity. For G. aprion and N. graeffei, caring for progeny seemingly required similar trade‐offs including nonphysiological activities (e.g. feeding) and responses, such as changes in condition, respiratory and digestive morphology, that potentially allowed brooders to compensate for parental care energy expenditure.

Selection on Sperm Count, but Not on Sperm Morphology or Velocity, in a Wild Population of Anolis Lizards

Sperm competition is a widespread phenomenon that shapes male reproductive success. Ejaculates present many potential targets for postcopulatory selection (e.g., sperm morphology, count, and velocity), which are often highly correlated and potentially subject to complex multivariate selection. Although multivariate selection on ejaculate traits has been observed in laboratory experiments, it is unclear whether selection is similarly complex in wild populations, where individuals mate frequently over longer periods of time. We measured univariate and multivariate selection on sperm morphology, sperm count, and sperm velocity in a wild population of brown anole lizards (Anolis sagrei). We conducted a mark-recapture study with genetic parentage assignment to estimate individual reproductive success. We found significant negative directional selection and negative quadratic selection on sperm count, but we did not detect directional or quadratic selection on any other sperm traits, nor did we detect correlational selection on any trait combinations. Our results may reflect pressure on males to produce many small ejaculates and mate frequently over a six-month reproductive season. This study is the first to measure multivariate selection on sperm traits in a wild population and provides an interesting contrast to experimental studies of external fertilizers, which have found complex multivariate selection on sperm phenotypes.

Inbreeding reduces fitness of seed beetles under thermal stress.

Human‐induced environmental change can influence populations both at the global level through climatic warming and at the local level through habitat fragmentation. As populations become more isolated, they can suffer from high levels of inbreeding, which contributes to a reduction in fitness, termed inbreeding depression. However, it is still unclear if this increase in homozygosity also results in a corresponding increase in sensitivity to stressful conditions, which could intensify the already detrimental effects of environmental warming. Here, in a fully factorial design, we assessed the life‐long impact of increased inbreeding load and elevated temperature on key life history traits in the seed beetle, Callosobruchus maculatus. We found that beetles raised at higher temperatures had far reduced fitness and survival than beetles from control temperatures. Importantly, these negative effects were exacerbated in inbred beetles as a result of increased inbreeding load, with further detrimental effects manifesting on individual eclosion probability and lifetime reproductive success. These results reveal the harmful impact that increasing temperature and likelihood of habitat fragmentation due to anthropogenetic changes in environmental conditions could have on populations of organisms worldwide.

Born to Be Wild: Evaluating the Zoo-Based Regent Honeyeater Breed for Release Program to Optimise Individual Success and Conservation Outcomes in the Wild

Evaluating the effectiveness of captive breeding programs is central to improving conservation outcomes in released animals. However, few studies have assessed the impact of the strategies and trade-offs involved in husbandry decisions and the selection of traits on the success of breeding programs. This study evaluated a range of husbandry features including an animal's environment, health, and traits of the released individual and its parents involved in the zoo-based Regent Honeyeater breed for release program to optimise individual reproductive success and survivability, leading to improved conservation outcomes in the wild. We analysed 285 birds using a penalised Cox proportional hazard model to assess survival and an ordinal logistic model to evaluate the reproductive success of zoo bred birds released to the wild. Key features identified by the study highlight the importance of having parents that are successful breeders and parents that have an overall higher lifetime reproductive output. However, there were associated quantity-quality trade-offs, as the success of young (i.e., released birds) produced by parents was negatively associated to the number of clutches per year (where one clutch per year was found optimal). The study demonstrated the importance of considering the parental effects on the traits of its offspring beyond its pedigree information and found there was an associated decline in fitness of its offspring with older fathers. Song tutoring using wild Regent Honeyeaters was also important for increased survival post-release. Other important factors are discussed within the review. In general, the study recommended that a multi-faceted approach in the assessment and evaluation of the captive breeding program, to identify markers that will improve conservation outcomes of future releases.

Individual‐based plant–pollinator networks are structured by phenotypic and microsite plant traits

Abstract The biotic and abiotic context of individual plants within animal‐pollinated plant populations can influence pollinator foraging behaviour. Pollinator movements regulate pollen flow among plant individuals, and ultimately determine individual plant reproductive success. Yet the underlying drivers of this context dependency of interactions at the population level and their functional consequences for individuals remain poorly known. Here we used a well‐characterised population of Halimium halimifolium (Cistaceae), a Mediterranean shrub species, in combination with exponential random graph models (ERGMs) to evaluate how the intrapopulation variation in plant attributes configures individual‐based plant–pollinator networks and determines their reproductive outcomes. Specifically, we assessed (a) how the intrinsic (i.e. phenotype and phenology) and extrinsic (i.e. microsite) plant attributes influenced the emerging configuration of the bipartite plant–pollinator network and the unipartite plant–plant network derived from pollinator sharing, and (b) how these plant attributes combined with the network topological position of individual plants affect their female fitness, measured as the total seed weight per plant. We found that both intrinsic and extrinsic plant attributes contributed substantially to explain the configuration of both the bipartite and the unipartite pollination network. Besides the effects of plant attributes, the functional group to which pollinator species belonged was also important to determine the variance in plant–pollinator interaction odds, while the probability of plants to share more pollinator species was additionally influenced by the spatial distance between those plants. Furthermore, our results showed that these influences of plant attributes on network structure can be translated into functional outcomes at the plant individual level, with direct consequences for intrapopulation fitness variation. Synthesis. This study builds towards a better understanding of the multiple drivers underlying the context dependency of plant–pollinator interactions and how they mediate the reproductive outputs of individual plants within a population. The application of our analytical framework allows a conceptual shift from descriptive to predictive research on the evolutionary and ecological processes that give rise to complex ecological networks at the population level.

The earlier the better? Nesting timing and reproductive success in subalpine cavity-nesting bees.

Reproductive timing can affect an organism's production of offspring and its offspring's success, both of which contribute to its overall fitness. In seasonal environments, the timing of reproductive activity may be restricted to short periods of the year owing to numerous potential selective pressures such as variation in daylength, weather, food availability, predation or competition. We documented the relationships between reproductive timing and individual reproductive success (total reproductive output and offspring success) in subalpine populations of five cavity-nesting solitary bee species. We also examined the relationships between bee reproductive success and environmental variables that are likely ultimate drivers of bee phenology in subalpine environments (i.e. seasonality of floral resource abundance and temperature). Over 6years, we recorded solitary bee nesting timing, egg production and offspring success using artificial nesting structures ('trap-nests') established at multiple study sites. We also quantified floral resources and recorded temperature throughout growing seasons. Bees nesting earlier in the season exhibited greater reproductive success. Reproductive output generally increased with floral abundance, although this relationship was weak and only significant for some bee species. Elevated temperatures were associated with increased nest construction rate, but not with greater reproductive output. These contrasting effects of temperature may have been driven by the negative relationship between temperature and bee longevity. Bees who nested for shorter durations of time (a proxy for longevity) produced fewer offspring, and individuals exhibiting the shortest nesting durations were also those that began nesting late in the season. Overall, bees who initiated nesting early and sustained activity for a long duration had the highest reproductive output. This work documents the relationship between reproductive phenology and fitness in wild insect populations and highlights the ways in which organisms can cope with the challenges of living in seasonal and highly variable environments.

Perceived mate competition risk influences the female mate choice and increases the reproductive effort in the annual killifish Millerichthys robustus

Female life-history strategies can be sensitive to social context, responding adaptively to current or future mate limitations by reproductive competition conditions. Competitive environments provide the conditions for adjusting reproductive decisions in order to compensate for the negative impacts of competition between individuals, thus maintaining reproductive fitness. This research aimed to test the effect of perceived competition risks for mate choice and their consequences in the reproductive effort of females of the annual killifish Millerichthys robustus induced throughout an audience effect. First, I evaluated the female mate choice using a classic dichotomous preference study based on male size, showing that the females do not show a significant preference for males of any size in a scenario without perceived competition; however, females turn selective under competition risk, choosing the large males. I then evaluated the reproductive effort of females through embryo production without an audience for 10 days, and next with an audience of females for two periods of 10 days. Results showed that females produced significantly more embryos when they perceived a risk of competition. Also, females turn selective under risk of competition, probably due to an increased parental investment expressed by the reduction of the female-male encounters and breeding rate, the increased reproductive effort and the time spent searching a mate. Females that mate with larger males may gain access to more benefits derived from his social status, as best territories and high-quality sites for the spawn, thus increasing the probabilities of survival for the females and their offspring. I propose that, as a life-history strategy to preserve individual fitness, the direction of the sexual selection is modified by the perceived competition risk, and that competition is not necessarily related with the high-cost investments; in fact, it may also have, beneficial effects for the individual female reproductive success.

Gene flow and reproductive success in ash (Fraxinus excelsior L.) in the face of ash dieback: restoration and conservation

• Key messageAsh dieback decreases individual reproductive success of ash trees leaving healthy ash overrepresented as seed and pollen parents for next-generation seedlings. Substantial gene flow over hundreds of meters combined with superior fertility of healthy trees creates optimism for the species’ future in European forests.• ContextHymenoscyphus fraxineus is causing high mortality in European ash (Fraxinus excelsior L.). Due to inheritable resistance to the pathogen, natural selection is likely to act in favour of improved resistance in ash forests following natural regeneration. Still, the frequency of healthy trees is low, and the effect of natural selection will depend on survival, reproductive success and the dispersal capacity of healthy trees under natural conditions.• AimsWe aim to test whether healthy trees contribute more to the next generation and to infer their potential for dispersing progenies across the forested landscape.• MethodsUsing parentage modelling, we estimate mating parameters and dispersal distances of seeds and pollen and compare realised reproductive success of healthy trees to that of unhealthy ones.• ResultsHealthy trees are overrepresented as the parents of randomly sampled seeds and seedlings in the forest, although that is more pronounced on the female side. We observe long dispersal events and estimate the mean seed and pollen dispersal distances as 67 m and 347 m, respectively.• ConclusionVariation in reproductive success results in selection in favour of lowered susceptibility to ash dieback. The large dispersal capacity decreases the risk of genetic bottlenecks and inbreeding and allows resistant trees to disperse their genes into the neighbourhoods of substantial sizes.

Mate value, intrasexual competition and sociosexual desire drive Brazilian women's well-being.

Well-being (vs. ill-being) might function as an internal guide for approaching (vs. avoiding) situations, strategies, and achievements that ancestrally led to higher (vs. lower) reproductive success. Indeed, coupled individuals report higher well-being than singles, while depressive individuals report lower mate value and higher sociosexuality. Here we investigate associations between well-being, depression and evolutionary reproduction-related aspects (mate value, intrasexual competition, age, and sociosexuality). Overall, 1,173 predominantly heterosexual Brazilian women (mean = 31.89; standard deviation = 11.10) responded to online instruments measuring self-perceived happiness, life-satisfaction, depression, mate value, intrasexual competition, age, and sociosexuality. Multiple regression models indicated that higher well-being was positively predicted by mate value and negatively by intrasexual competition and sociosexual desire, while the opposite was true for depression. Although intrasexual competition and unrestricted sociosexuality can, under some circumstances, increase individual reproductive success, they are risky and suboptimally effective strategies, thus leading to feelings of ill-being. Contrarily, affective long-term bonds, higher mate-value, and lower intrasexual competition might increase feelings of well-being, because this would lead to a safer route towards ancestral reproductive advantages.