Individual variation in baseline and stress-induced corticosterone and prolactin levels predicts parental effort by nesting mourning doves

Endocrine systems have an important mechanistic role in structuring life-history trade-offs. During breeding, individual variation in prolactin (PRL) and corticosterone (CORT) levels affects behavioral and physiological processes that drive trade-offs between reproduction and self-maintenance. We examined patterns in baseline (BL) and stress induced (SI; level following a standard capture-restraint protocol) levels of PRL and CORT for breeding mourning doves (Zenaida macroura). We determined whether the relationship of adult condition and parental effort to hormone levels in wild birds was consistent with life-history predictions. Both BL PRL and BL CORT level in adults were positively related to nestling weight at early nestling ages, consistent with the prediction of a positive relationship of hormone levels to current parental effort of adults and associated increased energy demand. Results are consistent with the two hormones acting together at baseline levels to limit negative effects of CORT on reproduction while maintaining beneficial effects such as increased foraging for nestling feeding. Our data did not support predictions that SI responses would vary in response to nestling or adult condition. The magnitude of CORT response in the parents to our capture-restraint protocol was negatively correlated with subsequent parental effort. Average nestling weights for adults with the highest SI CORT response were on average 10–15% lighter than expected for their age in follow-up visits after the stress event. Our results demonstrated a relationship between individual hormone levels and within population variation in parental effort and suggested that hormonal control plays an important role in structuring reproductive decisions for mourning doves.     

Predicting reproductive success from hormone concentrations in the common tern (<Emphasis Type="Italic">Sterna hirundo</Emphasis>) while considering food abundance

In birds, reproductive success is mainly a function of skill or environmental conditions, but it can also be linked to hormone concentrations due to their effect on behavior and individual decisions made during reproduction. For example, a high prolactin concentration is required to express parental behaviors such as incubation or guarding and feeding the young. Corticosterone level, on the other hand, is related to energy allocation or stress and foraging or provisioning effort. In this study, we measured individual baseline prolactin and corticosterone between 2006 and 2012 in breeding common terns (Sterna hirundo) using blood-sucking bugs. Reproductive parameters as well as prey abundance on a local and a wider scale were also determined during this period. Baseline prolactin and corticosterone varied significantly between years, as did breeding success. At the individual level, prolactin was positively and corticosterone was negatively linked to herring and sprat abundance. At the population level, we also found a negative link between corticosterone and prey abundance, probably reflecting overall foraging conditions. High prolactin during incubation was mainly predictive of increased hatching success, potentially by supporting more constant incubation and nest-guarding behavior. It was also positively linked to a lesser extent with fledging success, which could indicate a high feeding rate of young. Corticosterone concentration was positively related to high breeding success, which may be due to increased foraging activity and feeding of young. In general, our study shows that baseline prolactin and corticosterone levels during incubation can predict reproductive success, despite the presence of an interval between sampling and hatching or fledging of young.     

Social facilitation of insect reproduction with motor-driven tactile stimuli

Tactile stimuli provide animals with important information about the environment, including physical features such as obstacles, and biologically relevant cues related to food, mates, hosts and predators. The antennae, the principal sensory organs of insects, house an array of sensory receptors for olfaction, gustation, audition, nociception, balance, stability, graviception, static electric fields, and thermo-, hygro- and mechanoreception. The antennae, being the anteriormost sensory appendages, play a prominent role in social interactions with conspecifics that involve primarily chemosensory and tactile stimuli. In the German cockroach (Blattella germanica) antennal contact during social interactions modulates brain-regulated juvenile hormone production, ultimately accelerating the reproductive rate in females. The primary sensory modality mediating this social facilitation of reproduction is antennal mechanoreception. We investigated the key elements, or stimulus features, of antennal contact that socially facilitate reproduction in B. germanica females. Using motor-driven antenna mimics, we assessed the physiological responses of females to artificial tactile stimulation. Our results indicate that tactile stimulation with artificial materials, some deviating significantly from the native antennal morphology, can facilitate female reproduction. However, none of the artificial stimuli matched the effects of social interactions with a conspecific female.     

Does short-term fasting lead to stressed-out parents? A study of incubation commitment and the hormonal stress responses and recoveries in snow petrels

The hormonal stress response is flexible and can be modulated by individuals according to its costs and benefits. Therefore, it is predicted that parents in poor body condition should modify their hormonal stress response, and thus, redirect energy allocation processes from parental care to self-maintenance when stressors occur. To test this prediction, most studies on free-living vertebrates have only focused on the stress response while the stress recovery – how quickly hormonal levels return to baseline values – has been neglected. Moreover, most studies have only focused on corticosterone – the primary mediator of allostasis – without paying attention to prolactin despite its major role in mediating parental behaviors. Here, we examined the effect of a short-term fasting event on the corticosterone and prolactin stress responses and recoveries, and we subsequently explored their relationships with parental decision in the snow petrel (Pagodroma nivea). By comparing the hormonal profiles of fasting and non-fasting snow petrels, we showed that parents modulate their corticosterone (but not prolactin) stress response according to their energetic status. We also described for the first time the hormonal stress recoveries in wild birds and found that they did not differ between fasting and non-fasting birds. Importantly, egg neglect was negatively correlated with circulating prolactin but not corticosterone levels in this species, demonstrating therefore a complex link between body condition, parental behavior and circulating corticosterone and prolactin levels. We suggest that both corticosterone and prolactin play a major role in the way parents adjust to stressors. This multiple signaling may allow parents to fine-tune their response to stressors, and especially, to activate specific allostasis-related mechanisms in a timely manner.     

Hormone levels predict individual differences in reproductive success in a passerine bird

Hormones mediate major physiological and behavioural components of the reproductive phenotype of individuals. To understand basic evolutionary processes in the hormonal regulation of reproductive traits, we need to know whether, and during which reproductive phases, individual variation in hormone concentrations relates to fitness in natural populations. We related circulating concentrations of prolactin and corticosterone to parental behaviour and reproductive success during both the pre-breeding and the chick-rearing stages in both individuals of pairs of free-living house sparrows, Passer domesticus. Prolactin and baseline corticosterone concentrations in pre-breeding females, and prolactin concentrations in pre-breeding males, predicted total number of fledglings. When the strong effect of lay date on total fledgling number was corrected for, only pre-breeding baseline corticosterone, but not prolactin, was negatively correlated with the reproductive success of females. During the breeding season, nestling provisioning rates of both sexes were negatively correlated with stress-induced corticosterone levels. Lastly, individuals of both sexes with low baseline corticosterone before and high baseline corticosterone during breeding raised the most offspring, suggesting that either the plasticity of this trait contributes to reproductive success or that high parental effort leads to increased hormone concentrations. Thus hormone concentrations both before and during breeding, as well as their seasonal dynamics, predict reproductive success, suggesting that individual variation in absolute concentrations and in plasticity is functionally significant, and, if heritable, may be a target of selection.     

Serum immunoglobulin G levels are positively related to reproductive performance in a long-lived seabird, the common tern (Sterna hirundo)

The evolution of longevity requires a low risk of mortality from extrinsic factors, relative to intrinsic factors, so that individuals that differentially invest in physiological self-maintenance and minimize their annual reproductive costs will maximize lifetime fitness through a prolonged reproductive lifespan. The trade-off between reproductive effort and self-maintenance, as measured by immune function, has been well documented in short-lived birds, but is difficult to demonstrate in long-lived birds. To assess self-maintenance in a long-lived seabird, we measured serum protein levels, including immunoglobulin G (IgG = IgY), in 30 breeding pairs of common terns (Sterna hirundo) and their first-hatched (A) chicks. Most parents were of known age from banding as hatchlings; our sample was selected to contrast young breeders (6–9 years) with very old birds (17–23 years). Body-mass of the parents declined by 5% during the chick-rearing period, while serum protein levels were stable. Serum IgG levels were higher in parents of offspring with faster growth rates, while IgG levels were lower in parents whose broods were reduced by starvation. A-chicks in broods of two had higher IgG levels than singleton chicks. Albumin levels were not related to reproductive performance. Thus, despite adequate statistical power, we could find no evidence for a trade-off between reproduction and self-maintenance in common terns, even in old age. The results are consistent with life-history predictions for long-lived vertebrates, in which selection favors sustained self-maintenance across the reproductive lifespan. The positive relationships between IgG levels and reproductive performance indicate that IgG can be used as an index of parental “quality.”     

Removing the confound of time in investigating the regulation of serial behaviours: testosterone, prolactin and the transition from sexual to parental activity in male American kestrels

Understanding the relationships among variables can be difficult if the variables covary with time. Using a simple, commonly used statistical procedure to control for the passage of time, we demonstrate that some hormonal changes traditionally assumed to be causally related to the transition from sexual to parental behaviour can be explained by seasonal changes in the hormones and the fact that parental behaviour follows sexual behaviour in the course of breeding. We quantified immunoreactive prolactin (ir-prolactin) and testosterone concentrations in laboratory-housed and free-living male American kestrels, Falco sparverius, over the course of the breeding season and during sexual and parental phases of reproduction. We found that ir-prolactin increased while testosterone decreased with the transition from sexual to parental behaviour. ir-Prolactin increased with date (i.e. seasonally), whereas testosterone peaked when the frequency of clutch initiation was greatest and then decreased with date thereafter. Controlling for the effects of date eliminated the change in ir-prolactin associated with the transition from sexual to parental behaviour, revealing that prolactin variation associated with this behavioural transition in male kestrels is due, in large part, to seasonal changes in hormone concentrations and the serial nature of these behavioural states. Controlling for the effects of date further revealed that the testosterone difference between sexual and parental males decreases seasonally. It is possible that other phenomena traditionally attributed to environmental, behavioural, social, or other variables also may be explained by the association between such variables and the passage of time.     

Dominance,aggression and physiological stress in wild male Assamese macaques (Macaca assamensis)

In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale–multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.     

Serum prolactin levels and crop-sac development in ring doves during a breeding cycle

Using a turkey prolactin radioimmunoassay, the serum prolactin levels of male and female ring doves (Streptopelia risoria) during the breeding cycle were measured and their circulating prolactin levels were compared to crop-sac weight on a within-bird basis. During the early phase of the incubation period, crop weight showed a delayed response to prolactin stimulation and there was no correlation; during the midincubation period when prolactin and crop-sac weight were increasing, there was a strong positive correlation; around hatching, when prolactin was at its peak, there was no correlation. There were again strong positive correlations at later samples, when squabs were developing and both prolactin and crop-sac weight were declining. Thus, it appears that the correlation between the circulating prolactin level and crop-sac development depends on the stage of the breeding cycle. While males and females showed similar pattern of circulating prolactin during the period of incubation and parental care, only females consistently showed a postovulatory rise of prolactin. These results were discussed in the context of the role of prolactin in the breeding cycle.     

Decreasing prolactin levels leads to a lower diving effort but does not affect breeding success in Adélie penguins

Current research on seabirds suggests a key role of hormones in the trade-off between self-maintenance and parental investment through their influence on foraging decisions during the breeding period. Although prolactin is known to have major effects on parental care, its role in foraging behavior has rarely been investigated in seabirds to date.     

It takes two to tango: reproductive skew and social correlates of male mating success in a lek-breeding bird

Variance in reproductive success among individuals is a defining characteristic of many social vertebrates. Yet, our understanding of which male attributes contribute to reproductive success is still fragmentary in most cases. Male–male reproductive coalitions, where males jointly display to attract females, are of particular interest to evolutionary biologists because one male appears to forego reproduction to assist the social partner. By examining the relationship between social behaviour and reproductive success, we can elucidate the proximate function of coalitions in the context of mate choice. Here, we use data from a 4-year study of wire-tailed manakins (Pipra filicauda) to provide molecular estimates of reproductive skew and to test the hypothesis that male–male social interactions, in the context of coordinated displays, positively influence a male''s reproductive success. More specifically, we quantify male–male social interactions using network metrics and predict that greater connectivity will result in higher relative reproductive success. Our data show that four out of six leks studied had significant reproductive skew, with success apportioned to very few individuals in each lek. Metrics of male social affiliations derived from our network analysis, especially male connectivity, measured as the number of males with whom the focal male has extended interactions, were strong predictors of the number of offspring sired. Thus, network connectivity is associated with male fitness in wire-tailed manakins. This pattern may be the result of shared cues used by both sexes to assess male quality, or the result of strict female choice for coordinated display behaviour.     

Hormones associated with non-maternal infant care: a review of mammalian and avian studies

Hormonal changes during non-maternal infant care have been demonstrated in many cooperatively breeding bird species, some monogamous rodents and two species of New World primates. Coevolution of hormones and social traits may have provided for the different breeding systems that occur today. Several hormones have been shown to covary with the breeding systems of vertebrates. Elevated levels of the hormone prolactin with male parenting behaviours are common to many birds, rodents and the callitrichid monkeys Callithrix jacchus and Saguinus oedipus. In birds, prolactin may be elevated in both male and female breeders during various stages of nest building, egg laying, incubating and feeding of young. Testosterone levels appear to have an inverse relationship to prolactin levels during infant care in birds and rodents, but this relationship has not been examined for primates. In cooperatively breeding birds, helpers who remain at the nest also have elevated levels of prolactin when displaying parental care behaviours. Prolactin levels are elevated in helper callitrichid monkeys during the postpartum period. Monogamous male rodents demonstrate elevated prolactin levels with parental care behaviour but, in contrast to the birds, the mechanisms mediating prolactin increase appear to differ for male and female rodents. Two factors may influence male parental behaviours and hormonal changes: stimuli from the pregnant female and stimuli from the newborn pups; whereas maternal behaviours are influenced by the maternal hormones of the female and the pup stimuli. An experiential factor may also influence male parental behaviours. Neuropeptides such as oxytocin and vasopressin appear to be involved in male rodent parental care and there may be an interaction between a series of hormones and neurosecretions and stimuli from mates and pups. Studies of Saguinus oedipus, the cotton-top tamarin, suggest that prolactin levels are responsive to stimuli from contact with infants and the level of infant care experience influences the levels of prolactin with male infant care. Father tamarins also have elevated levels of prolactin before the birth of infants suggesting that cues from the pregnant female are important. Prolactin's role in parental care may have evolved from prolactin's role in other reproductive functions. Hormonal regulation of non-maternal care may occur due to a complex interaction of many hormones and neurotransmitters. Studies described here should provide the impetus for further work on parental care hormones in a wide variety of primates.     

Birth season glucocorticoids are related to the presence of infants in sifaka (Propithecus verreauxi)

The responses of plural breeding mammals to environmental stressors are little understood in free-ranging populations, but recent studies of singular breeders suggest that ecological factors and social milieu influence the variable physiological stress responses observed among individuals. Our previous studies examining faecal glucocorticoid (fGC)–behaviour interactions in plural breeding male sifaka (Propithecus verreauxi) show that fGC elevations coincide with specific dispersal events, particularly the eviction of subordinates by resident alpha males. This study examined the utility of fGC assays for assessing the stress responses of male sifaka to demographic changes in the population during the birth season. Analyses were based on 889 faecal samples collected over five birth seasons from 124 adult males residing in 55 different groups at Beza Mahafaly, Madagascar. Results show that fGC levels in males are unrelated to age, residence, group stability or rank, but are significantly and positively correlated with the presence of infants, annual elevations in weekly mean fGC concentrations in males paralleling increasing numbers of infants born annually in the population. These data are the first to show that in seasonal plural breeding species such as sifaka, elevated fGC in males reflects specific events related to reproduction rather than states or social context during the birth season.     

Context-dependent development of sexual ornamentation: implications for a trade-off between current and future breeding efforts

Allocation of resources into the development of sexual displays is determined by a trade-off between the competing demands of current reproduction and self-maintenance. When reproduction overlaps with acquisition of sexual ornamentation, such as in birds with a yearly post-breeding moult, such a trade-off can be expressed in elaboration of sexual traits used in subsequent matings. In turn, selection for elaboration of sexual ornaments should favour resolution of this trade-off through a modification of the ornaments' development, resulting in variable and life history-dependent development of sexual displays. Here we examined a novel hypothesis that the trade-off between current reproduction and development of sexual ornamentation in the house finch (Carpodacus mexicanus) can be mediated by the shared effects of prolactin - a pituitary hormone that regulates both parental care and moult in this species. We compared developmental variation in sexual ornamentation between breeding, nonbreeding, and juvenile males and examined the relative contribution of residual levels of prolactin and individual condition during moult to the acquisition of sexual ornamentation. Males that invested heavily in parental care entered post-breeding moult in lower condition and later in the season, but their higher plasma prolactin was associated with shorter and more intense moult ultimately resulting in equal or greater elaboration of sexual ornamentation compared with nonparental males. Elaboration of sexual ornamentation of nonparental males that entered moult in greater condition, but with lower prolactin, was produced by longer and earlier moult and by lesser overlap in moult between sexual ornaments. Ornamentation of juvenile males that acquire sexual ornamentation for the first time was closely associated with physiological condition during moult. We discuss the implications of such context-dependent ontogenies of sexual ornamentation and resulting differences in condition-dependence of sexual traits across life history stages on the evolution of female preference for elaborated sexual displays.     

Context-Dependent Plastic Response during Egg-Laying in a Widespread Newt Species

Previous research on predator-induced phenotypic plasticity mostly focused on responses in morphology, developmental time and/or behaviour during early life stages, but the potential significance of anticipatory parental responses has been investigated less often. In this study I examined behavioural and maternal responses of gravid female smooth newts, Lissotriton vulgaris, in the presence of chemical cues originating from invertebrate predators, Acilius sulcatus water beetles and Aeshna cyanea dragonfly larvae. More specifically, I tested the extent of oviposition preference, plasticity in egg-wrapping behaviour and plasticity in egg size when females had the possibility to lay eggs at oviposition sites with and without predator cues during overnight trials. I found that individuals did not avoid laying eggs in the environment with predator cues; however, individuals that deposited eggs into both environments adjusted the size of the laid eggs to the perceived environment. Females deposited larger eggs earlier in the season but egg size decreased with time in the absence of predator cues, whereas individuals laid eggs of average size throughout the investigated reproductive period when such cues were present. Also, egg size was found to be positively related to hatching success. Individuals did not adjust their wrapping behaviour to the presence of predator cues, but females differed in the extent of egg-wrapping between ponds. Females’ body mass and tail depth were also different between ponds, whereas their body size was positively associated with egg size. According to these results, female smooth newts have the potential to exhibit activational plasticity and invest differently into eggs depending on temporal and environmental factors. Such an anticipatory response may contribute to the success of this caudate species under a wide range of predator regimes at its natural breeding habitats.     

Dominance, aggression and physiological stress in wild male Assamese macaques (Macaca assamensis)

In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale–multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.     

Social modulation of androgen levels in male teleost fish

Androgens are classically thought of as the sex steroids controlling male reproduction. However, in recent years evidence has accumulated showing that androgens can also be affected by the interactions between conspecifics, suggesting reciprocal interactions between androgens and behaviour. These results have been interpreted as an adaptation for individuals to adjust their agonistic motivation and to cope with changes in their social environment. Thus, male-male interactions would stimulate the production of androgens, and the levels of androgens would be a function of the stability of its social environment ['challenge hypothesis', Gen. Comp. Endocrinol. 56 (1984) 417]. Here the available data on social modulation of androgen levels in male teleosts are reviewed and some predictions of the challenge hypothesis are addressed using teleosts as a study model. We investigate the causal link between social status, territoriality and elevated androgen levels and the available evidence suggests that the social environment indeed modulates the endocrine axis of teleosts. The association between higher androgen levels and social rank emerges mainly in periods of social instability. As reported in the avian literature, in teleosts the trade-off between androgens and parental care is indicated by the fact that during the parental phase breeding males decreased their androgen levels. A comparison of androgen responsiveness between teleost species with different mating and parenting systems also reveals that parenting explains the variation observed in androgen responsiveness to a higher degree than the mating strategy. Finally, the adaptive value of social modulation of androgens and some of its evolutionary consequences are discussed.     

Is negative density‐dependent reproduction regulated by density‐induced stress in root voles? Two field experiments

Density dependence in reproduction plays an important role in stabilizing population dynamics via immediate negative feedback from population density to reproductive output. Although previous studies have shown that negative density‐dependent reproduction is associated with strong spacing behavior and social interaction between individuals, the proximal mechanism for generating negative density‐dependent reproduction remains unclear. In this study, we investigated the effects of density‐induced stress on reproduction in root voles. Enclosed founder populations were established by introducing 6 (low density) and 30 (high density) adults per sex into per enclosure (four enclosures per density in total) during the breeding season from April to July 2012 and from May to August 2015. Fecal corticosterone metabolite (FCM) levels, reproductive traits (recruitment rate and the proportion of reproductively active individuals), and founder population numbers were measured following repeated live trapping in both years. The number of founders was negatively associated with recruitment rates and the proportion of reproductively active individuals, displaying a negative density‐dependent reproduction. FCM level was positively associated with the number of founders. The number of founder females directly affected the proportion of reproductive females, and directly and indirectly through their FCM levels affected the recruitment rate; the effect of the number of male founders on the proportion of reproductive males was mediated by their FCM level. Our results showed that density‐induced stress negatively affected reproductive traits and that density‐induced stress is one ecological factor generating negative density‐dependent reproduction.     

High Fidelity – No Evidence for Extra-Pair Paternity in Siberian Jays (Perisoreus infaustus)

Extra-pair paternity (EPP) in birds is related to a number of ecological and social factors. For example, it has been found to be positively related with breeding density, negatively with the amount of paternal care and especially high rates have been observed in group-living species. Siberian jays (Perisoreous infaustus) breed at low densities and have extended parental care, which leads to the expectation of low rates of EPP. On the other hand, Siberian jays live in groups which can include also unrelated individuals, and provide opportunities for extra-pair matings. To assess the potential occurrence of EPP in Siberian jays, we analysed a large data pool (n = 1029 offspring) covering ca. 30 years of samples from a Finnish Siberian jay population. Paternities were assigned based on up to 21 polymorphic microsatellite markers with the additional information from field observations. We were unable to find any evidence for occurrence of EPP in this species. Our findings are in line with earlier studies and confirm the generally low rates of EPP in related Corvid species. These results suggest that ecological factors may be more important than social factors (group living) in determining costs and benefits of extra-pair paternity.     

Modulation of the adrenocortical response to acute stress with respect to brood value, reproductive success and survival in the Eurasian hoopoe

Reproducing parents face the difficult challenge of trading-off investment in current reproduction against presumed future survival and reproduction. Glucocorticoids are supposed to mediate this trade-off because the adrenocortical response to stress disrupts normal reproductive behaviour in favour of self-maintenance and own survival. According to the brood-value hypothesis, individuals with a low survival probability until the next reproductive season have to invest in current reproduction, a process driven by a down-regulation of their adrenocortical response. If the adrenocortical response to stress effectively mediates the trade-off between current reproduction versus future survival and reproduction, we expect a negative relationship with reproductive success and a positive correlation of the adrenocortical stress response with survival. We studied the relationship between corticosterone secretion in parents and their current brood value, reproductive success and survival in a short-lived multi-brooded bird, the Eurasian hoopoe Upupa epops. The adrenocortical response to acute handling stress was correlated with the brood value within the individual (first and second broods of the year) and between individuals. Birds breeding late in the season mounted a lower total corticosterone response to acute stress than birds breeding earlier, while females showed lower levels than males. We observed a negative relationship between the adrenocortical stress response and rearing success or fledging success in females, as predicted by the brood-value hypothesis. However, we could not evidence a clear link between the adrenocortical stress response and survival. Future research testing the brood-value hypothesis and trade-offs between current reproduction and future survival should also measure free corticosterone and carefully differentiate between cross-sectional (i.e. between-individual) and individual-based experimental studies.