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The cost of parental care has long been thought to favor the evolution of cooperative breeding, because breeders can provide reduced parental care when aided by alloparents. Oxidative stress—the imbalance between reactive oxygen species and neutralizing antioxidants—has been proposed to mediate the cost of parental care, though results from empirical studies remain equivocal. We measured changes in oxidative status during reproduction in cooperatively breeding superb starlings (Lamprotornis superbus) to gain insight into the relationships among breeding status, parental care, and oxidative stress. We also compared the oxidative cost of reproduction in the cooperatively breeding superb starling to that in a sympatric non-cooperatively breeding species, the greater blue-eared glossy starling (L. chalybaeus), to determine whether cooperatively breeding individuals face reduced oxidative costs of parental care relative to non-cooperatively breeding individuals. Breeders and alloparents of the cooperative species did not differ in oxidative status throughout a breeding attempt. However, individuals of the non-cooperative species incurred an increase in reactive oxygen metabolites proportionally to an individual’s workload during offspring care. These findings suggest that non-cooperative starlings experience an oxidative cost of parental care, whereas cooperatively breeding starlings do not. It is possible that high nest predation risk and multi-brooding in the cooperatively breeding species may have favored reduced physiological costs of parental care more strongly compared to pair-breeding starlings. Reduced physiological costs of caring for young may thus represent a direct benefit that promotes cooperative breeding. [ABSTRACT FROM AUTHOR]

We quantified patterns of male and female parental care of the Swallow Tanager (Tersina viridis) in the activities of nest building, incubation, and feeding of nestlings during 4 reproductive seasons in Morrinhos, Goiás. The first individuals arrived in late June and the last individuals departed at the end of November, but incubation and feeding of nestlings occurred primarily in September and October, respectively. Males did not participate in incubation, but they contributed to nest building (24%) and feeding nestlings (55%; n = 8 nests). The results demonstrate biparental care and a socially monogamous breeding system for Swallow Tanager; however, low male involvement in total parental care, especially in incubation, and marked sexual dichromatism suggest the occurrence of extra-pair fertilization (EPF). [ABSTRACT FROM AUTHOR]

Fragmentation and degraded habitat conditions can result in increased competition for critical resources, altered mating systems, and can eventually result in population declines or extinction. We investigated the degree to which habitat degradation and habitat loss impacted the breeding ecology of Greater Prairie-Chickens at 3 study sites across relatively intact grasslands in Kansas, USA. Across all 3 study systems, we found similar rates of multiple mating by females at 14–20% of broods. In addition, we found evidence for facultative nest parasitism of conspecific females. Prairie-chicken females inhabiting more intact and less fragmented landscapes with a higher probability of survival did not engage in parasitic egg laying, whereas ∼17% of females inhabiting a more fragmented and isolated landscape engaged in parasitic egg laying. Parasitic egg layers tended to be older females that parasitized nests of yearling females. Parasitic egg layers only laid parasitically after an initial nesting attempt failed. Parasitic laying females all renested and hatched their own clutches. When counting parasitically laid eggs, parasitic egg-laying females laid significantly more eggs than nonparasitic egg layers and, as a result, had 25% greater fecundity. This case study across the relatively intact grasslands of Kansas highlights how land use and management can influence adaptive life history traits and population stability. Consequently, understanding these relationships will be essential to developing effective future conservation and management plans for prairie-grouse. [ABSTRACT FROM AUTHOR]

Individuals should adjust investment in parental care in order to maximize current and future reproductive success. In cooperative breeders, where helpers assist with raising offspring, larger groups may allow for a reduction in investment (load lightening) of each individual. Additionally, the type of individual, and thus the social context, can play an important role in individual investment. Less attention has been paid to how provisioning rules vary across ecological contexts, although theory suggests that individuals can only afford to reduce their investment when nestling starvation is unlikely, thus under mild conditions. Here, we tested whether previously reported provisioning rules based on social context vary with ecological conditions, by experimental manipulation of signals of chick need, in the cooperatively breeding red-winged fairy-wren, Malurus elegans. Previous work in this species has shown that all group members load-lighten with additional male helpers, but not in response to the number of female helpers in the group (additive care). We show that experimental begging playback resulted in all individuals increasing their provisioning rates, indicating that our treatment was perceived as increased chick need. However, in contrast to our prediction that load lightening should only occur when individuals can afford to do so, signals of increased chick need did not stop individuals from reducing their investment with an increasing number of male helpers in the group. These results suggest that despite some flexibility in parental effort, individuals use strict rules with respect to group composition, suggesting that individual provisioning effort is based on multiple integrated cues, and responses to changes in the environment are highly context dependent. Highlights • Provisioning rules were consistent across contexts in red-winged fairy wrens. • All group members increased feeding rates in response to begging playback. • Load lightening occurred in both the begging and control playback treatments. [ABSTRACT FROM AUTHOR]

Parental investment theory predicts that parents should adjust their investment in offspring defence according to offspring value (i.e. the probability they will contribute to the next generation). Although previous research has shown this offspring value prediction is generally supported in unitary organisms, the ‘superorganisms’ formed by advanced colonial organisms have rarely been tested, and never by direct manipulation of offspring value. As an important complement to correlational studies, such a test would help better illuminate the applicability of the parental investment theory to that higher level of biological organization, as well as provide insight into the depth of the superorganism analogy. Here I use colonies of the fire ant, Solenopsis invicta , in a manipulative experiment to test whether superorganisms behave as predicted by the parental investment theory and invest more in defence (deliver larger venom doses) when protecting higher-value offspring. In addition, to test a proposed mechanism for observed increases, I conducted an experiment to investigate whether S. invicta alarm pheromone modulates venom dose. I found that colonies delivered larger venom doses when defending nests containing higher-value (sexual) offspring than when defending worker-destined brood, but I found no venom dose increase as a result of additional alarm pheromone. The conformity of S. invicta colonies to the offspring value prediction of the parental investment theory supports the theory's applicability to their higher (superorganismal) level of animal organization. It furthermore underscores that the superorganism concept is deeper than simple anatomical/organizational analogy, but extends also to colony-level behaviour. Highlights • Parental investment theory: parents should defend offspring according to their value. • This prediction is well supported in unitary organisms but less well tested in superorganisms. • Fire ant colonies were tested using a paired experimental design. • Colonies increased defence when nests contained higher-value (sexual) offspring. • Superorganism concept extends beyond anatomical analogy to colony-level behaviour. [ABSTRACT FROM AUTHOR]

Flexible compensatory parental care takes place when one parent increases its parental effort in response to its mate's reduction or absence. Although this behavioural response is well known in species with biparental care, the few cases attributed to species with uniparental care are usually based on descriptive observations of apparent compensation without a proper examination of its effects on offspring fitness. In the harvestman Serracutisoma proximum , a species with female uniparental care, harem-owning males stand on unattended clutches when the egg-tending females desert or die. Here, we experimentally investigated under field conditions whether this behaviour constitutes an example of true parental compensation. We evaluated the effects of ecological and life history factors on males' proximity to unattended clutches. We also presented egg predators to the harem-owning males and parental females when they were standing on their clutches and compared their aggressive responses. Finally, we compared egg survival between three manipulation groups: in the absence of both adults; in the presence of only the harem-owning males; and in the presence of the parental females. We observed that males spent considerably less time standing on clutches than parental females, rarely attacked potential egg predators (in contrast to parental females which commonly exhibited aggressive behaviours) and, ultimately, had no effect on offspring survival. Our results do not support the existence of paternal compensation in S. proximum. Instead, we hypothesize that males' behaviour comprises a tactic that increases: (1) fertilization success of unfertilized eggs retained by egg-tending females that temporarily abandon the clutch; and/or (2) mating success with newcomer mates that trade copulations for the opportunity to cannibalize the unattended offspring. This study demonstrates that it is imperative to formally test adaptive assumptions before deriving conclusions on the evolution of complex traits and their implications, as an apparently adaptive behaviour is not always what it seems. Highlights • Individuals may adjust their parental care in response to their partner's behaviour. • Males stay close to the offspring when females are absent in an arachnid species. • We conducted experiments to evaluate male defensive behaviour and egg survival. • Males do not attack egg predators and eggs survive as well with or without a male. • Instead of paternal care, males' behaviour may be a component of mating effort. [ABSTRACT FROM AUTHOR]

Despite an extensive body of theoretical and empirical literature on biparental cooperation, it is still unclear whether offspring fare equally, better or worse when receiving care by two parents versus a single parent. Some models predict that parents should withhold the amount of care they provide due to sexual conflict, thereby shifting as much of the workload as possible to their partner. This conflict should lead to offspring faring worse with two parents. Yet, other models predict that when parents care for their offspring together, their individual contributions can have synergistic (more than additive) effects on offspring fitness. Under this scenario, biparental cooperation should lead to offspring faring better with two parents. We address this fundamental question using a unique experimental design where we compared offspring fitness when the two parents worked together (biparental treatment) and when they worked separately (uniparental treatment), while keeping constant the amount of resources and number of offspring per parent across treatments. This made it possible to directly compare the biparental treatment to the sum of the male and female contributions in the uniparental treatment. Our main finding was that offspring grew larger and were more likely to survive to adulthood when reared by both parents than a single parent. This is the first empirical evidence for a synergistic effect of biparental cooperation on offspring fitness and could provide novel insights into the conditions favouring the evolution of biparental cooperation. [ABSTRACT FROM AUTHOR]

Abstract: Background: We hypothesized that maternal nutrient restriction (NR) would increase activity and behavioral indicators of anxiety (self‐directed behaviors, SDBs) in captive baboons (Papio sp.) and result in more protective maternal styles. Methods: Our study included 19 adult female baboons. Seven females ate ad libitum (control group), and eight females ate 30% less (NR group) and were observed through pregnancy and lactation. Results: Control females engage in higher rates of SDB than NR females overall (P ≤ .018) and during the prenatal period (P ≤ .001) and engage in more aggressive behavior (P ≤ .033). Control females retrieved infants more than NR females during weeks 5‐8 postpartum (P ≤ .019). Conclusions: Lower SDB rates among prenatal NR females reduce energy expenditure and increase available resources for fetal development when nutritionally restricted. Higher infant retrieval rates by controls may indicate more infant independence rather than maternal style differences. [ABSTRACT FROM AUTHOR]

Abstract: Parental effects on offspring performance have been attributed to many factors such as parental age, size and condition. However, we know little about how these different parental characteristics interact to determine parental effects, or the extent to which their effect on offspring depends on either the sex of the parent or that of the offspring. Here we experimentally tested for effects of variation in parents’ early diet and inbreeding levels, as well as effects of parental age, and for potential interactive effects of these three factors on key aspects of offspring development in the mosquitofish (Gambusia holbrooki). Older mothers produced offspring that were significantly smaller at birth. This negative effect of maternal age on offspring size was still evident at maturation as older mothers had smaller daughters, but not smaller sons. The daughters of older mothers did, however, reach maturity sooner. Paternal age did not affect offspring body size, but it had a complex effect on their sons’ relative genital size. When initially raised on a food‐restricted diet, older fathers sired sons with relatively smaller genitalia, but when fathers were initially raised on a control diet their sons had relatively larger genitalia. The inbreeding status of mothers and fathers had no significant effects on any of the measured offspring traits. Our results indicate that the manifestation of parental effects can be complex. It can vary with both parent and offspring sex; can change over an offspring's life; and is sometimes evident as an interaction between different parental traits. Understanding this complexity will be important to predict the role of parental effects in adaptation. [ABSTRACT FROM AUTHOR]

To evaluate long-term changes in reproductive characteristics and maternal effects in Pacific bluefin tuna in the Sea of Japan, we performed histological observations of the most advanced group of oocytes and measured batch fecundity and egg diameter. We sampled 6767 individuals from 1994 to 2015. The main spawning periods were from June to August, and the spawning intervals in June, July, and August were 1.34, 1.18, and 1.10 days, respectively. At higher sea surface temperatures, egg diameter might be smaller because the storage time of the yolk is limited due to the shorter spawning intervals at higher sea surface temperatures. Spawning periods were consistent throughout the survey years. There were significant positive correlations between batch fecundity and fork length and between batch fecundity and gutted body weight. The relative condition factor and relative batch fecundity were calculated. A generalized linear model showed that the relative batch fecundity was significantly correlated with year effects and fork length, and the egg diameter was significantly correlated with year effects and relative condition factor. Our results show that better nourished spawners have larger eggs, and larger eggs could positively affect the larval survival rate. [ABSTRACT FROM AUTHOR]

Parental care is a critical component for determining reproductive success both for a current set of offspring but also over the lifetime of the individual. The hormone prolactin has often been implicated as a parental care hormone across taxa but causal relationships have only been strongly demonstrated in mammals and in a few select species of birds. For instance, in mammals, maternal care towards foster pups can be induced by exogenous treatment with prolactin, in concert with other reproductive hormones involved in pregnancy. We aimed to address this causal mechanism in birds by artificially elevating prolactin during the nest building and egg laying stages using vasoactive intestinal peptide (VIP) and then exposing them to foster chicks. We predicted that increasing prolactin would increase brooding and feeding behaviors towards foster chicks compared to the saline control group. Parental behavior towards foster chicks was only shown by individuals who had initiated clutches regardless of treatment. VIP treatment had no effect on parental behavior; however, a positive relationship was found between male and female feeding rates in the VIP but not control group. Our results suggest that both eggs and chicks are sufficient to stimulate foster care, perhaps through endogenous prolactin signalling, while further elevations of prolactin may serve to synchronize parental behaviors between pairs. [ABSTRACT FROM AUTHOR]

Abstract: Recreational boating activity has the potential to generate noise pollution that may influence wild fish. Such noise may be particularly relevant to fish engaged in parental care (PC), where alterations in behaviour could influence individual fitness and productivity of fish populations. Here, the PC behaviour of the freshwater largemouth bass (Micropterus salmoides) was examined to determine whether disturbance from boat noise altered paternal behaviour. Changes in nest‐tending and brood‐guarding behaviour were measured following exposure to noise treatments of 1‐min duration using underwater playbacks of recorded boat noises. One experiment compared the behaviour of bass tending eggs before, during, and after exposure to high‐speed or idling combustion motors, or an electronic bow‐mounted trolling motor. No significant differences in the time on nest, number of pectoral fin beats, and number of turns between the pre‐treatment, treatment, and post‐treatment periods for all three motor types were observed. A second experiment assessed the impacts of noise (high‐speed combustion motor only) on the behaviour of nesting bass across the development stages of offspring (i.e. egg, egg‐sac fry, and swim‐up fry). During the egg‐sac fry stage, nest‐guarding males turned significantly less on the nest during the noise treatment compared with the long‐term post‐treatment period, indicating a stage‐specific impact of boat noise on parental behaviour. The effect was transient, however, and limited to the period that the noise was present. Given that PC and recreational boating activity tend to co‐occur in nearshore areas, prolonged or frequent repeated exposure of nesting fish to boat noise during the egg‐sac fry stage could have adverse consequences for fitness and reproductive output. Efforts to restrict recreational boating activity in the vicinity of fish engaged in PC (e.g. through the use of set‐backs) would be a risk‐averse approach to mitigating the effects of noise pollution on fish. [ABSTRACT FROM AUTHOR]

Life experiences and parenting play an important role in infant development. To prevent developmental risks and support parents in their educational role, it is important to identify the determinants of infant development. In this study, we investigate the association between child, maternal, family and social variables, and infant development, as well as we investigate the determinants of infant development. A sample of 86 healthy infants and their mothers participated in this study. At 11-months, infant development was assessed with Schedule of Growing Skills II (SGSII). To assess mother-infant quality of interaction, the dyads were observed in free play at 12-months using CARE-Index. Maternal sensitivity and infant cooperative behavior were correlated with SGSII global scores and sub-scales. Infant development was associated with maternal years of education, number of siblings, birth weight or risks in pregnancy. Number of nurse visits attended by parents during the infant first year and birth age were determinants of infant development. [ABSTRACT FROM AUTHOR]

In the present study, we compared mother–infant relationships in 57 mother–infant dyads residing in two wild, semi‐provisioned (22 mother–infant dyads in 2014, 35 dyads in 2015) groups of rhesus macaques (Macaca mulatta) in the Nanwan Nature Reserve for Rhesus Macaques, Hainan, China. We also compared reproductive success between these two groups. The ecology and provisioning regime for each group was similar. These groups differed however, in size. Group 1 contained ∼35 individuals and Group 2 contained ∼120 individuals. Data were collected over a 2‐year period (2014–2015). We found that during the birth season, mother–infant relationships in the larger group were characterized by less time in contact and more time separated than in the smaller group. Mothers in the smaller group initiated more contact and proximity with their infants. During the mating season when infants were approximately 6 months old, mother–infant relationships in the smaller group were more rejecting. We also found that birth rates were significantly higher but infant survivorship (to 1‐year‐old) was significantly lower in the smaller group. Moreover, higher‐ranking mothers in the larger group were characterized by a higher reproductive output than females of lower rank. In the smaller group, female rank did not affect reproductive output. There was, however, no clear relationship between infant survivorship and maternal rank. We hypothesize that differences in reproductive success and changes in mother–infant relationships between the birth and mating seasons reflect differences in the costs and benefits of group size: females in the larger group faced (i) higher intragroup feeding competition leading to a reduction in birth rate but also (ii) lower predation risk, resulting in higher infant survival rate compared to females in the smaller group. The results of this study point to the tradeoffs that primate females face in living in smaller and larger social groups. [ABSTRACT FROM AUTHOR]

Abstract: Reproductive strategies such as parental care have been pivotal in evolutionary innovations such as endothermy in birds and mammals. The diversity of reproductive biology across the squamates provides a unique opportunity for elucidating the selective forces responsible for the evolution of various reproductive strategies. Here, I report on the reproductive biology of the southern African python (Python natalensis), based on a 7‐year study of free‐ranging pythons, revealing a behavioural complexity not usually expected for snakes. Mating occurred in the austral winter, with individual males following females for more than 2 months. As is typical for pythons, females brooded eggs by coiling around the clutch. Females are capital breeders; they lost ~40% body mass during a breeding event and did not breed in consecutive years. There was no evidence of the facultative thermogenesis that has been reported in congeners, suggesting that facultative thermogenesis has arisen independently more than once in Python. Reproductive females thermoregulated more carefully than non‐reproductives, maintaining higher, more stable Tbs at all stages of reproduction, especially while brooding. This was achieved by a stereotypic basking regime facilitated by ‘facultative melanism’, with females darkening significantly for the entire breeding event. Mothers remained with neonates at the nest site for approximately 2 weeks after hatching. During this time, mothers alternated between brief bouts of basking on the surface and coiling around the hatched eggs, on which the neonates rested. Neonates formed an aggregation near the burrow entrance to bask during the day, individually returning to the nest intermittently throughout the day. During the night, neonates remained within the mother's coils on the hatched eggs. This study highlights the diversity of reproductive biology within Python and cautions against generalization in this regard. This is the first unambiguous report of maternal care of neonates in an oviparous snake. [ABSTRACT FROM AUTHOR]

Recent evidence indicates that acute activation of 5-HT2A receptors causes a disruption of maternal behavior in rats. However, the behavioral mechanisms underlying such a disruption are not known. We addressed this issue using two behavioral approaches targeting the maternal motivational and emotional processing systems. First, we used the pup-separation technique to increase maternal motivation to see whether pup separation is capable of reducing the maternal disruptive effect of TCB-2 (a high-affinity 5-HT2A agonist) treatment. On postpartum days 4 and 6, different groups of Sprague-Dawley dams were treated with the TCB-2 (5.0 mg/kg, sc) or vehicle and their maternal behaviors were tested after either a 4-h pup-separation or no-pup-separation condition. Although acute TCB-2 injection disrupted maternal behavior, this disruption was not attenuated by pup separation, even after we optimized the timing of separation to maximize its increase on maternal motivation. Acute TCB-2 also impaired the retrieval of food pellets, suggesting a general effect on motivated behaviors. Next, we used a pup preference test and found that dams treated with TCB-2 exhibited an even stronger preference to pups over a male conspecific than vehicle-treated dams, indicating an enhanced motivational and emotional processing of the rewarding property of pups. These findings suggest that TCB-2 has a disruptive effect on rat maternal behavior, and this disruption is not likely due to the drug’s effect on mothers’ motivational and emotional processing of the incentive salience of pups, although this motivational suppression account cannot be completely ruled out. Future work could explore other possible behavioral mechanisms, such as the drug’s effect on executive function. [ABSTRACT FROM AUTHOR]

Abstract: Early‐life trade‐offs faced by developing offspring can have long‐term consequences for their future fitness. Young offspring use begging displays to solicit resources from their parents and have been selected to grow fast to maximize survival. However, growth and begging behaviour are generally traded off against self‐maintenance. Oxidative stress, a physiological mediator of life‐history trade‐offs, may play a major role in this trade‐off by constraining, or being costly to, growth and begging behaviour. Yet, despite implications for the evolution of life‐history strategies and parent–offspring conflicts, the interplay between growth, begging behaviour and resistance to oxidative stress remains to be investigated. We experimentally challenged wild great tit (Parus major) offspring by infesting nests with a common ectoparasite, the hen flea (Ceratophyllus gallinae), and simultaneously tested for compensating effects of increased vitamin E availability, a common dietary antioxidant. We further quantified the experimental treatment effects on offspring growth, begging intensity and oxidative stress. Flea‐infested nestlings of both sexes showed reduced body mass during the first half of the nestling phase, but this effect vanished short before fledging. Begging intensity and oxidative stress of both sexes were unaffected by both experimental treatments. Feeding rates were not affected by the experimental treatments, but parents of flea‐infested nests fed nestlings with a higher proportion of caterpillars, the main source of antioxidants. Additionally, female nestlings begged significantly less than males in control nests, whereas both sexes begged at similar rates in vitamin E‐supplemented nests. Our study shows that a parasite exposure does not necessarily affect oxidative stress levels or begging intensity, but suggests that parents can compensate for negative effects of parasitism by modifying food composition. Furthermore, our results indicate that the begging capacity of the less competitive sex is constrained by antioxidant availability. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies demonstrate that pheromones can be costly to produce and emit and, therefore, the types and quantities that they express are likely to covary with individual condition. Previous experiments reveal that, when given the opportunity to breed and care for young, male burying beetles Nicrophorus vespilloides go on to produce a higher amount of their sex pheromone and attract more females than control males that do not exhibit parental care. This finding is surprising because parental care is usually assumed to be energetically costly, reducing the future capacity to invest in sexual signalling. However, burying beetles reproduce on dead vertebrates and the carrion meal might enable males to acquire resources that can subsequently be allocated to pheromone signalling. Alternatively, males might accumulate pheromone precursors because they do not emit their sex pheromone during brood care. To shed light on the mechanisms of enhanced pheromone emission after brood care, in the present study, we test the effect of diet quality, social condition during care (biparental versus uniparental care) and an experimentally enforced calling pause on subsequent male pheromone emission, body weight and energy storage components. The experimentally enforced calling pause and social condition during brood care demonstrate no impact on pheromone quantity. However, the results of the present study suggest that the vertebrate carrion meal during brood care partly explains enhanced pheromone release after care. Unravelling the biosynthetic pathways of the pheromone components and analyzing the impact of potential microbial symbionts on pheromone production represents a fruitful avenue for future research. [ABSTRACT FROM AUTHOR]

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The majority of altricial bird species defend their brood against predators more intensively in nestlings rather than eggs stage. Several hypotheses have been proposed to explain this difference. The majority of existing experimental studies have recorded a gradually increasing intensity of nest defence supporting the reproductive value hypothesis. We have compared nest defence in two nesting stages of the red‐backed shrike against two predators of adult birds and against two predators of nests. While the nests with nestlings were defended by parents against three out of four predators, nests with eggs were almost not defended at all. This rapid change in parent nest defence supports rather the vulnerability hypothesis, predicting that the threat to nests with nestlings increases rapidly after hatching, as they became more conspicuous due to their begging and parental provisioning. Unlike most of the species tested previously, the red‐backed shrike uses very vigorous mobbing towards predators. We suggest that the occurrence of this active mobbing (strikes, including physical contact) is a good proxy of the current threat to the nest. [ABSTRACT FROM AUTHOR]

Multiple matings result in varying paternity share based on mating interval and order. Thus, assessing the effect of mating interval and order on patterns of sperm usage and paternity is crucial. We designed consecutive and delayed double-mating experiments to investigate paternity variation in ladybird, Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae), using two distinct morphs of the species as phenotypic markers of paternity. The time to commence mating, copulation duration and reproductive output were recorded. The morphs of the offspring from the two setups were taken as a measure of paternity accumulated by the males. The time to commence mating decreased for the second mating in the consecutive mating treatment, while the reverse was observed in the delayed mating treatment. Consecutive double matings reduced the mating duration. Fecundity increased when second mating occurred after a few days, though percent egg viability remained unaffected. The second male accrued higher paternity (P2 = 0.61) than the first male (P1 = 0.39) in the consecutive mating treatment, while in the delayed mating treatment, the overall paternity share of the first 0.49 (P1) and last male was equal 0.51 (P2). Thus, our study revealed that both mating order and the time interval between successive matings regulate the male paternity share. This finding is reported for the first time in this ladybird species. [ABSTRACT FROM AUTHOR]

Behavioral adjustments and parental decisions during reproduction can influence the thermal environment at nests, yet our understanding into how environmental factors (i.e., temperature and precipitation) constrain an adult's ability to balance self-maintenance and incubation demands is limited. To expand our understanding of how species respond to environmental factors, we investigated the reproductive ecology of two ground-nesting species (northern bobwhite [ Colinus virginianus ] and scaled quail [ Callipepla squamata ]) in a region (i.e., the Southern Great Plains) prone to thermal variability (i.e., extreme hot and cold temperatures). Specifically, our objective was to examine how temperature and precipitation directly influenced behavioral adjustments (i.e., off-bout duration, frequency, and nest attentiveness) and parental decisions (i.e., nest site selection), and indirectly influenced nest fate. Overall, we found that parents chose to nest in sites that were significantly cooler in temperature than randomly selected sites, and parents further altered the thermal environment experienced by embryos through incubation behavior. Daily precipitation and average ambient temperature and/or their interaction best predicted incubation behaviors, yet each species differed in the timing (i.e., morning vs. evening), frequency, and duration of off-bouts. Furthermore, successful nests were associated with cooler nest site temperatures for bobwhite and warmer nest site temperatures for scaled quail. Our finding of relatively stable (35.5 °C) incubation temperature for developing embryos of both species suggests that ground-nesting birds are able to regulate microclimate through behavioral adjustments and parental decisions even under extreme temperature fluctuations. Nevertheless, the ability for a ground-nesting species to effectively modify behavioral adjustments and decisions may be altered during long periods of enhanced physiological and environmental stress. [ABSTRACT FROM AUTHOR]

Maternal behavior is a highly motivated and well-organized social behavior. Previous studies have reported that anticonvulsants are frequently used in postpartum bipolar disorder. However, the maternal disruptive effect of the anticonvulsants has not been explored. The purpose of the present study was to examine the effect of anticonvulsants lamotrigine and riluzole on maternal behavior in postpartum female rats. On postpartum Day 3, Sprague-Dawley mother rats were given a single intraperitoneal injection of vehicle, lamotrigine (15, 25, 35 mg/kg), or riluzole (2, 4, 8 mg/kg). Maternal behavior was tested 30 min before and after injection. Animals treated with lamotrigine or riluzole had a longer pup retrieval latency, retrieved fewer pups into the nest, spent less time on nursing pups, as well as on building the disturbed nest, and animals treated with riluzole spent less time on pup licking. Whereas, the drugs in the tested doses did not shorten the total duration of behavior unrelated to maternal behavior. Overall, these data indicate that lamotrigine and riluzole disrupt major components of maternal behavior in postpartum female rats, but do not inhibit the behaviors unrelated to maternal behavior, which indicates that the maternal disruptive effect is not due to nonspecific sedative effect. [ABSTRACT FROM AUTHOR]

Maternal behavior and anxiety are potently modulated by the brain corticotropin-releasing factor (CRF) system postpartum. Downregulation of CRF in limbic brain regions is essential for appropriate maternal behavior and an adaptive anxiety response. Here, we focus our attention on arguably the most important brain region for maternal behavior, the hypothalamic medial preoptic area (MPOA). Within the MPOA, mRNA for CRF receptor subtype 1 (protein: CRFR1, gene: Crhr1 ) was more abundantly expressed than for subtype 2 (protein: CRFR2, gene: Crhr2 ), however expression of Crhr1 , Crhr2 and CRF-binding protein (protein: CRFBP, gene: Crhbp ) mRNA was similar between virgin and lactating rats. Subtype-specific activation of CRFR, predominantly CRFR1, in the MPOA decreased arched back nursing and total nursing under non-stress conditions. Following acute stressor exposure, only CRFR1 inhibition rescued the stress-induced reduction in arched back nursing while CRFR1 activation prolonged the decline in nursing. Furthermore, inhibition of CRFR1 strongly increased maternal aggression in the maternal defense test. CRFR1 activation had anxiogenic actions and reduced locomotion on the elevated plus-maze, however neither CRFR1 nor R2 manipulation affected maternal motivation. In addition, activation of CRFR1, either centrally or locally in the MPOA, increased local oxytocin release. Finally, inhibition of CRFBP (a potent regulator of CRFR activity) in the MPOA did not affect any of the maternal parameters investigated. In conclusion, activity of CRFR in the MPOA, particularly of subtype 1, needs to be dampened during lactation to ensure appropriate maternal behavior. Furthermore, oxytocin release in the MPOA may provide a regulatory mechanism to counteract the negative impact of CRFR activation on maternal behavior. [ABSTRACT FROM AUTHOR]

Defending offspring provides fitness benefits to parents, but is costly. To moderate costs, parents should adjust aggressive responses to the threat posed by different species entering their territory. However, few studies have experimentally tested behavioral adjustments in response to the threat posed by different types of intruders, particularly in the field, and in environments with an array of heterospecific intruders. Here, using a biparental cichlid, the poor man's tropheus (Hypsophrys nematopus), we investigated whether males and females in the wild invest equally into offspring defense and what impact the absence of a partner might have on the quality of offspring defense provided by a solitary parent. In a separate experiment, we assessed responses of breeding pairs to 3 common heterospecific intruders that pose different levels of threat to the breeding pair and their brood. We found that both paired and unpaired females invested significantly more into territorial aggression than males. However, unpaired females were unable to fully compensate for the absence of their partner, with intruders left to venture closer to their offspring. Furthermore, we show that breeding pairs can readily discriminate between heterospecific intruders, with pairs responding quicker and more aggressively towards species that posed a greater potential threat. Our results demonstrate that biparental species can have extensive behavioral flexibility in their aggressive responses towards intruders, even in environments with a high frequency of territory incursion. The quality of territorial defense can nevertheless be compromised if one parent is left to defend the brood alone. [ABSTRACT FROM AUTHOR]

In many monogamous species, females behave aggressively toward other females, as they may threaten their exclusive access to paternal resources. However, in species with a high degree of breeding asynchrony not all females are true reproductive rivals. Female ornamentation that advertises sexual receptivity is a possible mechanism whereby parental females could assess the potential threat of rival females and attack only those which could challenge their mating status. Convict cichlids (Amatitlania siquia) are sexually dichromatic, monogamous fish that exhibit biparental care. Females develop gold ventral coloration when reproductively receptive and actively court males. We presented breeding pairs of convict cichlids with confined conspecific females to investigate whether parental response was affected by the intruder's reproductive status. We also investigated whether differences in partner quality within breeding pairs mediated the response to intruders, as mate quality influences both intra- and intersexual dynamics in many monogamous species. We found parental females responded more aggressively to reproductive intruders and that parental females mated to high quality males decreased the aggression they directed at general brood predators during the reproductive intruder presentation. Contrary to our predictions, we also found that males behaved aggressively toward reproductive intruders, particularly when paired with small females. Our results indicate that both parents engage in pair-bond defense and that differences in partner quality determine the level of aggression directed at extra-pair reproductive females. These findings suggest that when biparental care greatly increases offspring survival, reproductive success for both sexes may be maximized by cooperation and coordination, rather than conflict. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the importance of nongenetic heredity in the evolutionary process is a major topic in modern evolutionary biology. We modified a classical gene‐network model by allowing parental transmission of gene expression and studied its evolutionary properties through individual‐based simulations. We identified ontogenetic time (i.e. the time gene networks have to stabilize before being submitted to natural selection) as a crucial factor in determining the evolutionary impact of this phenotypic inheritance. Indeed, fast‐developing organisms display enhanced adaptation and greater robustness to mutations when evolving in presence of nongenetic inheritance (NGI). In contrast, in our model, long development reduces the influence of the inherited state of the gene network. NGI thus had a negligible effect on the evolution of gene networks when the speed at which transcription levels reach equilibrium is not constrained. Nevertheless, simulations show that intergenerational transmission of the gene‐network state negatively affects the evolution of robustness to environmental disturbances for either fast‐ or slow‐developing organisms. Therefore, these results suggest that the evolutionary consequences of NGI might not be sought only in the way species respond to selection, but also on the evolution of emergent properties (such as environmental and genetic canalization) in complex genetic architectures. [ABSTRACT FROM AUTHOR]

Abstract: Parental care is highly variable, reflecting that parents make flexible decisions in response to variation in the cost of care to themselves and the benefit to their offspring. Much of the evidence that parents respond to such variation derives from handicapping and brood size manipulations, the separate effects of which are well understood. However, little is known about their joint effects. Here, we fill this gap by conducting a joint handicapping and brood size manipulation in the burying beetle Nicrophorus vespilloides. We handicapped half of the females by attaching a lead weight to their pronotum, leaving the remaining females as controls. We also manipulated brood size by providing each female with 5, 20 or 40 larvae. In contrast to what we predicted, handicapped females spent more time provisioning food than controls. We also found that handicapped females spent more time consuming carrion. Furthermore, handicapped females spent a similar amount of time consuming carrion regardless of brood size, whereas controls spent more time consuming carrion as brood increased. Females spent more time provisioning food towards larger broods, and females were more likely to engage in carrion consumption when caring for larger broods. We conclude that females respond to both handicapping and brood size manipulations, but these responses are largely independent of each other. Overall, our results suggest that handicapping might lead to a higher investment into current reproduction and that it might be associated with compensatory responses that negate the detrimental impact of higher cost of care in handicapped parents. [ABSTRACT FROM AUTHOR]

Accumulating evidence suggests that within‐individual plasticity of behavioural and physiological traits is limited, resulting in stable among‐individual differences in these aspects of the phenotype. Furthermore, these traits often covary within individuals, resulting in a continuum of correlated phenotypic variation among individuals within populations and species. This heterogeneity, in turn, affects individual fitness and can have cross‐generational effects. Patterns of trait covariation, among‐individual differences, and subsequent fitness consequences have long been recognized in reptiles. Here, we provide a test of patterns of among‐individual heterogeneity in behaviour and physiology and subsequent effects on reproduction and offspring fitness in the garter snake Thamnophis elegans. We find that measures of activity levels vary among individuals and are consistent within individuals in reproductive female snakes, indicating stable behavioural phenotypes. Blood hormone and glucose concentrations are not as stable within individuals, indicating that these traits do not describe consistent physiological phenotypes. Nonetheless, the major axes of variation in maternal traits describe behavioural and physiological phenotypes that interact to predict offspring body condition and mass at birth. This differential allocation of energy to offspring, in turn, strongly influences subsequent offspring growth and survival. This pattern suggests the potential for strong selection on phenotypes defined by behaviour–physiology interactions. [ABSTRACT FROM AUTHOR]

Parenting is a multicomponent social behavior that is essential for the survival of offspring in many species. Despite extensive characterization of individual brain areas involved in parental care, we do not fully understand how discrete aspects of this behavior are orchestrated at the neural circuit level. Recent progress in identifying genetically specified neuronal populations critical for parenting, and the use of genetic and viral tools for circuit-cracking now allow us to deconstruct the underlying circuitry and, thus, to elucidate how different aspects of parental care are controlled. Here we review the latest advances, outline possible organizational principles of parental circuits and discuss future challenges. [ABSTRACT FROM AUTHOR]

Co-operative breeders provide parental care to non-filial offspring—a behaviour known as ‘alloparental care’. While inclusive fitness benefits are a widely accepted driver of alloparental care in kin-based social groups, such indirect benefits are lost in non-kin societies. Among such societies, theory predicts that the degree of parental and alloparental effort should therefore be proportional to an individual’s genetic contribution to mixed broods—depending upon reproductive options. Using genotyping data across five to 12 microsatellite loci for individuals from 20 social groups (67 adults and 153 nestlings), we assessed whether kinship or proportional reproductive success explained trends in parental and alloparental effort in the Smooth-billed Ani (Crotophaga ani), a joint-nesting cuckoo species. Nocturnal incubation in this species appears to be performed almost exclusively by a single male. We first report significantly higher degrees of relatedness between adults within social groups (r¯ = 0.208, n = 114 dyads), than between social groups (r¯ = 0.120, n = 893 dyads), suggesting that inclusive fitness benefits may in part explain uneven allocation of parental effort. Second, we show that nocturnal incubation status is a significant predictor of reproductive success in males, as nocturnal incubators sire a greater proportion of nestlings in mixed-parentage broods. While patterns of reproductive skew appear high at 80% paternal confidence (B¯ = 0.052, p = 0.061), we report no significant deviation from an egalitarian breeding framework. Our results revealed similar patterns of reproductive allocation to closely related Groove-billed Anis (Crotophaga sulcirostris); however, differences in male reproductive skew and within-group relatedness across crotophagids are highlighted and offer insight into social evolution among anis. [ABSTRACT FROM AUTHOR]

The pre-fledging survival of Greylag goslings (Anser anser) is known to be influenced by parenting style and particularly parental vigilance. Visual and acoustic cues may be important in parental vigilance: if vision is blocked, for example in a highly structured habitat, acoustic recognition of the goslings by their parents would be beneficial. We confronted parental and non-parental Greylag Geese with playbacks of gosling distress calls and analyzed their behavioral responses. Parental geese showed a significant increase in their vigilance behavior during and after playbacks while geese without offspring showed increased comfort behavior. In a permutated discriminant function analysis, we found no family-specific vocal cues in gosling calls, and potential call familiarity did not have any effect on parental behavioral responses. Vigilance in families was further influenced by the number of goslings and gosling age, with increased vigilance when the number of goslings was high, and when goslings were younger. Parental females were more vigilant than parental males, suggesting differences in parental investment between males and females. We conclude that visual cues may be more important in offspring-related vigilance than calls, which elicited different behavioral responses depending on the social class of the geese. [ABSTRACT FROM AUTHOR]

Predator-specific alarm calls may have a variety of context-specific functions. Parents of the oriental tit, Parus minor, use the ‘jar’ call in response to the presence of a snake near the nests, and the nestlings respond by escaping the nest cavity. This specific function can be observed only when nestlings are able to fledge. Do tits use the ‘jar’ call only in a situation when nestlings are physically able to jump out of the nest? We measured parental responses to live snake in 8 nests. The use of ‘jar’ call by parents was not modified by the ability of their nestlings to escape out of the nest. This suggests that fledging in response to ‘jar’ call by old nestlings evolved later than the evolutionary emergence of referential snake alarm calls, and that the ancestral function of ‘jar’ call was probably not related to triggering of fledging in old nestlings. [ABSTRACT FROM AUTHOR]

To better understand the potential costs and benefits of prolonged parental care in gregarious species, we studied post-weaning associations in a marked population of mountain goats (Oreamnos americanus) monitored for 22 years. We calculated the occurrence and frequency of associations involving 1- and 2-year-old juveniles. We investigated (1) the influence of maternal characteristics and population size on the formation of post-weaning associations, (2) the short-term costs of associations on maternal reproductive success, and (3) the short-term benefits of associations on life-history traits of juveniles. We found that barren mothers associated more frequently with 1-year-olds than summer yeld and lactating mothers. Associations with 2-year-olds tended to increase the probability that a mother would be barren the following year. Post-weaning associations did not influence the body mass of newborn kids nor the body mass and survival of juveniles. We discuss how benefits for associated juveniles may appear later in life. [ABSTRACT FROM AUTHOR]

Background: Ocimum sanctum (OSE) has been used in the Indian system of traditional medicine (Ayurveda) for the treatment and prevention of various diseases. However, the contradictory reports regarding the reproductive safety of OSE prompted us to re-verify its effect on the reproductive system by following internationally accepted Organization for Economic Cooperation and Development guideline 415. Objective: To study the effect of aqueous/methanolic extract of OSE (OciBest) on the male and female reproductive performance of Wistar rats. Materials and Methods: Rats were orally gavaged with OciBest at dose levels of 0, 250, 500, and 1000 mg/kg. Males were administered with OciBest for 12 weeks before and during the mating period. On the other hand, females received OciBest for 2 weeks before mating until the end of the lactation period. Results: OciBest at 1000 mg/kg did not induce any adverse effects on the reproductive performance of male and female rats. All the treated parent animals survived until the end of the study period with no major signs of clinical toxicity. The body weights, food consumption, male and female fertility indices, organ weights, as well as gross pathological and histopathology observations in parent animals, did not reveal any treatment-related adverse effects. Moreover, in comparison to the control groups, OciBest did not induce any treatment-related adverse effects to the offsprings. Conclusion: Thus, no-observed adverse effect level was found up to 1000 mg/kg dose, suggesting the safety of OciBest for reproductive system. [ABSTRACT FROM AUTHOR]

Introduction: Continued development and refinement of resting state functional connectivity (RSFC) fMRI techniques in both animal and clinical studies has enhanced our comprehension of the adverse effects of stress on psychiatric health. The objective of the current study was to assess both maternal behavior and resting state functional connectivity (RSFC) changes in these animals when they were dams caring for their own young. It was hypothesized that ECSS exposed dams would express depressed maternal care and exhibit similar (same networks), yet different specific changes in RSFC (different individual nuclei) than reported when they were adult females.Methods: We have developed an ethologically relevant transgenerational model of the role of chronic social stress (CSS) in the etiology of postpartum depression and anxiety. Initial fMRI investigation of the CSS model indicates that early life exposure to CSS (ECSS) induces long term changes in functional connectivity in adult nulliparous female F1 offspring.Results: ECSS in F1 dams resulted in depressed maternal care specifically during early lactation, consistent with previous CSS studies, and induced changes in functional connectivity in regions associated with sensory processing, maternal and emotional responsiveness, memory, and the reward pathway, with robust changes in anterior cingulate circuits.Limitations: The sample sizes for the fMRI groups were low, limiting statistical power.Conclusion: This behavioral and functional neuroanatomical foundation can now be used to enhance our understanding of the neural etiology of early life stress associated disorders and test preventative measures and treatments for stress related disorders. [ABSTRACT FROM AUTHOR]

Offspring of older parents frequently showreduced longevity, but the mechanisms driving this so-called 'Lansing effecť are unknown. While inheritance of short telomeres from older parents could underlie this effect, studies to date in different species have found mixed results, reporting positive, negative or no association between parental age and offspring telomere length (TL). However, most of the existing evidence is from non-experimental studies in which it is difficult to exclude alternative explanations such as differential survival of parents with different telomere lengths. Here we provide evidence in the zebra finch that offspring fromolder parents have reduced lifespans.As a first step in disentangling possible causes, we used an experimental approach to examine whether or not we could detect pre-natal paternal effects on offspring TL. We found that zebra finch embryos fathered by old males have shorter telomeres than those produced by the same mothers but with younger fathers. Since variation in embryonic TL persists into post-natal life, and early life TL is predictive of longevity in this species, this experimental study demonstrates that a paternally driven pre-natal TL reduction could at least in part underlie the reduced lifespan of offspring from older parents. [ABSTRACT FROM AUTHOR]

The effect of pup cross-fostering by the house mouse Mus musculus and the mound-building mouse M. spicilegus on the odor preferences of sexually mature individuals has been studied for the first time. House and mound-building mice reared by females of a closely related species did not prefer any of the odors, in contrast to intact individuals of these species. Some individuals reared by females of a closely related species preferred the odor of foster species to conspecific odor. Early olfactory experience has been shown to alter the response of house mice and mound-building mice to odors of their own species and foster species. [ABSTRACT FROM AUTHOR]

A male's reproductive success often depends on both his phenotypic quality and the quality of the resources he controls. An important and longstanding challenge for evolutionary biologists has been to disentangle these 2 often-correlated factors. Here, we present a large multiyear, multipopulation field study along with complementary laboratory experiments aimed at disentangling the effects of male quality and nest quality in driving male reproductive success in the plainfin midshipman fish, Porichthys notatus. We investigate how these factors are linked to reproductive success using a number of different reproductive success components, including female attraction, cuckolder male attraction, egg acquisition, and rearing success. We show in the field that both male size and nest size are important correlates of reproductive success in this paternal care-giving species, but also that nest size can impose a limit on reproductive success regardless of the quality of the male nest owner. Females in the laboratory prefer large males when nest size is held constant, but females show no detectable preference for larger nests when nest size is varied and male size is held constant. We also explore a suite of additional male and nest traits-including male body condition, sonic organ investment, nest species richness, and nest density. Our results highlight how male and resource quality are multivariate concepts that incorporate information from the male phenotype, the ecological environment, and even the social environment and shape mating systems by influencing an animal's choice of mating partners and nesting sites. [ABSTRACT FROM AUTHOR]

The vocalizations of some young brood-parasitic birds closely resemble those of their host's young. Such similarities might arise because hosts bestow the greatest parental care in response to their own species' call type. We used a playback experiment to assess the effectiveness of the nestling call structures of 2 brood parasites, the specialist screaming cowbird (Molothrus rufoaxillaris) and the generalist shiny cowbird (M. bonariensis), in stimulating parental provisioning in a shared host, the baywing (Agelaioides badius). Screaming cowbird begging calls closely resemble those of baywing young and thus should best exploit any bias for species- specific cues. Shiny cowbird calls, in contrast, are unlike baywings but can instead exploit nonspecific sensory biases for long call duration and syllable repetition. We found that playback of screaming cowbird's mimetic calls elicited increases in feeding rates equivalent to those of playback of the host's own young, whereas shiny cowbird calls failed to increase provisioning rates above those of no-broadcast control sessions. These results indicate that baywings discriminate between nestling call structures in favor of their own species calls when adjusting parental investment and support the view that selection for optimal host provisioning can favor vocal mimicry by parasitic offspring. [ABSTRACT FROM AUTHOR]

In the dwarf hamster ( Phodopus campbelli ), activational effects of testosterone (T) and estradiol (E 2 ) in the regulation of paternal behavior have been repeatedly rejected because peripheral concentrations of E 2 do not change across the reproductive cycle of males. Further, castration no affected paternal behavior despite that both T and E 2 concentrations decreased significantly. However, the role of these hormones has not been evaluated in models of castration and hormonal replacement in virgin males. Here, we analysed the effects of E 2 and T in paternal behavior in virgin male dwarf hamster ( Phodopus campbelli ). Thirty paternal (PAT) males were bilaterally castrated; of them, 10 were implanted with T, 10 with E 2 and 10 males received no treatment. Other 10 PAT males underwent sham-castration. Seventeen aggressive (AGG) males were also bilaterally castrated; of these, 10 AGG received E 2 replacement, 7 were not treated. Other 7 AGG males were submitted to sham-castration. Following treatments, paternal behavior tests were conducted again. T and E 2 levels in plasma were quantified by radioimmunoassay (RIA). The results showed that the treatments did not affect the paternal behavior of males that were initially paternal. Neither castration nor sham-castration surgery affected the behavior of AGG males. However, when these males were treated with E 2 and the concentrations of this hormone increase significantly they became paternal. Our data suggest that an increase in E 2 levels shifted infanticidal behavior to paternal behavior in dwarf hamster. [ABSTRACT FROM AUTHOR]

Brood reduction by parents via infanticide is considered rare in passerine birds; however, this behavior may be underreported because of the difficulties observing behaviors at the nest and because researchers tend to attribute partial nestling loss to other causes. Here, we report a confirmed incidence of parental infanticide by Dickcissels ( Spiza americana). While video-recording parental behavior, we documented a 4-day-old nestling being removed by a female Dickcissel. This bird was also observed brooding and feeding, so this event was likely a parental infanticide. We subsequently examined monitoring data from 162 hatched Dickcissel nests across 2 breeding seasons to identify instances of unexplained partial nestling loss, which could potentially be attributable to infanticide. Our data indicate that 9.1-12.7% of hatched nests experienced these events. Infanticide by genetic parents could (1) benefit survival of remaining brood mates by reducing food requirements, disease, or predation risk; (2) represent responses to cuckoldry or intraspecific brood parasitism; (3) represent cases of mistaken chick identity; or (4) be triggered by unusual stressors. We recommend that ecologists monitoring bird nests consider infanticide as a possible explanation for partial nestling loss. Received 3 November 2016. Accepted 27 November 2017. [ABSTRACT FROM AUTHOR]

Sex allocation models still fail to predict the complex sex ratio patterns in broods of vertebrates. A major problem when studying mother–brood interactions is the difficulty in disentangling hypotheses involving maternal preferences from processes that do not imply maternal manipulation. We studied maternal resource allocation in mixed-sex, same-sex and single-chick broods in the great bustard, Otis tarda . Females normally rear a single chick, and previous work has shown that maternal investment influences male more than female breeding success. Therefore, mothers of two-chick broods were assumed to be in good condition and candidates to show a preference for sons. Results showed that male chicks of mixed-sex broods remained close to the mother for twice as long as their sisters, and received double the number of maternal feedings. However, sex differences in maternal feeding rate disappeared when considering only simultaneous begging approaches from both siblings. Proximity to the mother and its interaction with begging approach intensity were the factors determining the higher begging success of male chicks. In single-chick broods, females did not receive fewer maternal feedings than males. Overall, our results suggest that female chicks of mixed-sex broods become outcompeted by their larger brothers, which remain close to the mother much longer, preventing their sisters from taking a larger share of maternal feedings. We conclude that mothers do not show a preference for feeding male over female chicks, and that the sex differences in feeding rate are determined by the higher food requirements of male chicks due to their sexually selected, much faster growth rates. The higher mortality of females in mixed-sex broods contrasts with the pattern of male-biased mortality typical in this species, and supports our interpretation of an asymmetric competitive ability of male offspring as the mechanism responsible for the sex bias in maternal expenditure. [ABSTRACT FROM AUTHOR]

The discovery of a trait in a new lineage, especially one distantly related to those already known to express the trait, affords the opportunity to test and refine existing hypotheses for that trait’s evolution and to develop new ideas. Peter Weygoldt made such a discovery, reporting the first instance of a frog that feeds its young and, even more remarkably, the first instance of dependent tadpoles that perform solicitation displays before being fed ( 1980. Behav. Ecol. Sociobiol. 7, 329–332 ). This discovery has featured prominently in taxonomic surveys of parental care and offspring-parent communication, but more importantly has expanded the questions that are and can be asked about these topics. I review the advances in knowledge of the natural history of the frog Weygoldt studied as well as the theoretical frameworks that inform and are informed by these advances. I highlight ideas and information about parental care in O. pumilio that are central to broadly understanding the evolution of parental care. Our understanding of the evolution of sex roles will, for example, improve by following Weygoldt’s finding that male O. pumilio care for clutches with detailed accounting of the costs and benefits mothers and fathers might pay for performing this task. When a parent transports tadpoles from a terrestrial clutch to an aquatic nursery, it sets the stage for sibling competition for this resource (transport), and proximate and ultimate tests for such conflict will inform more general ideas about how conflict and cooperation shape nuclear families. That the begging displays of tadpole O. pumilio are performed in solitary nurseries makes this species uniquely suited to test honest-signaling models for the evolution of offspring-parent communication. By detailing the implications and possibilities stemming from Weygoldt’s work, I hope to inspire readers to follow Weygoldt’s lead and his example of careful and detailed observation. [ABSTRACT FROM AUTHOR]

In recent decades, theoretical and empirical work has investigated the relative roles of costs and benefits in inhibiting excessive displays of begging to parents. Whether costs are important in maintaining reliability of offspring signals is still debated, in part because empirical evidence for costs is conflicting. Nearly 90% of empirical studies have focused on birds. Costs may differ between birds and other animal groups, but more information is needed about non-avian systems. In this study, we tested for evidence of costs of begging in an anuran, Oophaga pumilio , in which tadpoles vibrate vigorously against mother frogs to solicit nutritive eggs. First, we tested whether a realistic manipulation of begging effort affected tadpole growth over two weeks, and found evidence for such physiological costs. Second, we tested whether the presence of a natural predator would alter begging behavior. Tadpoles begged when hungry, but begged significantly less when both hungry and viewing a spider, suggesting that they have evolved to reduce potential costs of predation risk when begging. Thus, we demonstrate the first example of costs via both physiological expenditure and predation risk in a non-avian species. Unlike most birds which rear offspring in clutches, O. pumilio mothers rear tadpoles in individual sites, suggesting that in the absence of sibling effects, multiple costs of begging work concomitantly to prevent the expression and evolution of excessive or indiscriminate signaling. Future studies of begging from a comparative perspective will continue to augment our understanding of the mechanisms behind the evolution of parent-offspring communication. [ABSTRACT FROM AUTHOR]

ABSTRACT: Capture‐induced abandonment of ungulate neonates has been poorly understood until recently, likely often underestimated, and anecdotally reported to occur at variable rates. This complex maternal behavior adversely affects the accuracy, efficiency, cost‐effectiveness, and consequently the overall value of behavioral and survival studies. To follow‐up on a previous study where we reported an 18.4% rate of abandonment of moose (Alces alces) neonates following helicopter‐assisted capture in Minnesota, USA, we tracked the movement behavior of 12 and 13 moose neonates fitted with global positioning system (GPS) collars during 8–15 May 2014 (phase 1) and 21 May–19 June (phase 2), respectively. These efforts were part of an overall study of reproductive success and cause‐specific mortality in Minnesota's remaining viable but declining moose population. During phase 1, 7 (3 M, 4 F) of 12 (6 M, 6 F) neonates were abandoned by 5 of 9 dams. Our capture‐induced abandonment contingency plan and monitoring of hourly location fixes of the GPS‐collared newborns and their dams allowed us to recover 6 of the 7 abandoned neonates alive and in good condition. During phase 2, we reduced our capture team from 3 to 4 to 2 persons and limited handling to fitting the GPS collar and sexing the neonate ( x ¯ = 0.7 min). Capture‐induced abandonment decreased to 1 of 10 dams abandoning a set of twins. Mean distance of dams to capture site (calving site) 1 hour pre‐ and 1 hour post‐capture did not indicate a predisposition to abandonment. However, differences in distances of dam to capture site, dam to neonate(s), and neonate to capture site over 48–96 hours post‐capture suggested a clear pattern of capture‐induced abandonment. None of the birth, capture, neonate, or dam characteristics examined indicated a predisposition to capture‐induced abandonment at the study cohort level. However, minimizing capture‐induced abandonment through rapid handling of neonates will greatly increase the overall value of field studies that rely on the capture of animals. © 2017 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Variations in maternal care in the rat influence the development of individual differences in behavioral and endocrine responses to stress. This study aimed to examine the interaction between intragastric intubation during late gestation and postpartum stress, induced by pup separation, on maternal behavior and on dams' emotional state and HPA axis function. Rats received intragastric intubation of water on days 12–20 of gestation or remained untreated in their home cage (naïve dams). Pup separation was used as a model of postpartum stress. The procedure consisted of a daily separation of the dam from its litter for 3 h from PND 3 until PND 15. Pup separation was carried out in both naïve and intubated dams. The behavioral results indicate that the association of these two stressors significantly decreased arched-back nursing (ABN) and licking and grooming (LG), behaviors considered important parameters to discriminate the high quality of maternal care. Moreover, dams that received both stressors displayed less nest building and blanket nursing behaviors; no effect on the frequency of passive and total nursing was recorded. The analysis of single effects on ABN and LG, revealed that dams that underwent gestational stress induced by intragastric intubation displayed less LG, but ABN was overall unchanged. On the contrary, pup separation stress significantly increased ABN and LG upon reunion of naïve dams with their pups. Treatments per se or the association of both induced modest changes in plasma levels of allopregnanolone and corticosterone that likely did not influence maternal care. These data show that the association of a mild stress during gestation with an unfavorable experience after parturition had a significant impact on maternal care. This effect seems independent from HPA axis activation or from changes in emotional state; further studies would be necessary to ascertain the neural changes that could contribute to altered maternal behavior in stressed mothers. Moreover, these results suggest that the use of intragastric intubation during gestation would interfere with measures of drug-induced changes in maternal behavior and likely their consequences on the offspring. [ABSTRACT FROM AUTHOR]

Abstract: Organisms can modify their surrounding environment, but whether these changes are large enough to feed back and alter their evolutionary trajectories is not well understood, particularly in wild populations. Here we show that nutrient pulses from decomposing Atlantic salmon (Salmo salar) parents alter selection pressures on their offspring with important consequences for their phenotypic and genetic diversity. We found a strong survival advantage to larger eggs and faster juvenile metabolic rates in streams lacking carcasses but not in streams containing this parental nutrient input. Differences in selection intensities led to significant phenotypic divergence in these two traits among stream types. Stronger selection in streams with low parental nutrient input also decreased the number of surviving families compared to streams with high parental nutrient levels. Observed effects of parent‐derived nutrients on selection pressures provide experimental evidence for key components of eco‐evolutionary feedbacks in wild populations. [ABSTRACT FROM AUTHOR]

Male parental care is an important social behavior for several mammalian species. Psychosocial stress is usually found to inhibit maternal behavior, but effects on paternal behavior have been less consistent. We tested the effects of social defeat stress on pair bond formation and paternal behavior in the monogamous California mouse ( Peromyscus californicus ). Social defeat reduced time spent in a chamber with a stranger female during a partner preference test conducted 24 h after pairing, but increased latency to the first litter. In 10 min partner preference tests conducted after the birth of pups, both control and stressed males exhibited selective aggression towards stranger females. Unlike prairie voles, side by side contact was not observed in either partner preference test. Stressed male California mice engaged in more paternal behavior than controls and had reduced anxiety-like responses in the open-field test. Defeat stress enhanced prodynorphin and KOR expression in the medial preoptic area (MPOA) but not PVN. Increased KOR signaling has been linked to increased selective aggression in prairie voles. Together the results show that defeat stress enhances behaviors related to parental care and pair bonding in male California mice. [ABSTRACT FROM AUTHOR]

Parental care is a widespread phenomenon observed in many diverse taxa. Neuroendocrine systems have long been thought to play an important role in stimulating the onset of parental behavior. In most birds with altricial young, circulating prolactin (PRL) levels are low during non-breeding times and significantly increase during late incubation and early post-hatch chick care. Because of this pattern, PRL has been suggested to be involved in the initiation of parental care in birds, but rarely has this hypothesis been causally tested. To begin testing the hypothesis, we inhibited the release of endogenous PRL with bromocriptine (BR) on the 3 days prior to hatching in incubating parents and the first 2 days of post-hatch care, when PRL was found to be highest in zebra finches. Nest temperatures were recorded during all 5 days and parental behavior was recorded on days 1–2 post-hatch. In addition to hormonal systems, reproductive experience may also influence parental care; therefore, we tested age-matched inexperienced and experienced pairs in each group. BR either eliminated or drastically reduced chick brooding and feeding behavior, resulting in decreased nest temperatures on days 1 and 2 post-hatch. Experienced control birds fed chicks more than inexperienced birds and control females fed more than males. Chick feeding behavior was positively correlated in control male-female pairs, but not in BR pairs. This is one of the few causal studies to demonstrate that PRL is necessary for post-hatch care in a biparental songbird, and is the first to show this effect in zebra finches. [ABSTRACT FROM AUTHOR]