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Hal Whitehead - One of the best experts on this subject based on the ideXlab platform.
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Characterizing Alloparental Care in the pilot whale (Globicephala melas) population that summers off Cape Breton, Nova Scotia, Canada
Marine Mammal Science, 2016Co-Authors: Joana F. Augusto, Timothy R. Frasier, Hal WhiteheadAbstract:Alloparental Care happens when a calf is Cared for by an adult that is not their parent. Although Alloparental Care is common in social mammals, its prevalence is difficult to assess in cetaceans, and has not been studied in Globicephala melas. A population off Cape Breton, Nova Scotia, has been studied from whale-watching vessels since 1998, during July and August each year. From 2009 to 2011, we collected photo identifications of calves and the adults accompanying them. Alloparental Care was considered to be occurring when a calf was identified with more than one companion. We found that 85.7% of calves in 2009, 80.6% of calves in 2010 and 63% of calves in 2011 had alloparents. Mothers were difficult to identify. Nevertheless, none of the other companions of calves were assigned to the same unit as the mother. Five Carers were sexed, four of them males. There were no cases of within- or between-year Alloparental Care reciprocity. It is possible that delayed reciprocity is happening on a larger time scale in this population, but the most likely explanation is that Alloparental Care is a byproduct of this species’ social structure, with a very small cost to the alloparent's fitness.
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Who Cares? Between-group variation in Alloparental Caregiving in sperm whales
Behavioral Ecology, 2009Co-Authors: Shane Gero, Dan Engelhaupt, Luke Rendell, Hal WhiteheadAbstract:Although the details of the various systems of alloCare in primates, rodents, and carnivores have been well described, little is known about the existence of Alloparental Care in cetaceans. It is believed that the matrilineal social organization of the sperm whale functions to provide vigilant allomothers for calves at the surface while mothers make deep dives for food. Sperm whale females do have a system of alloCare, but details are unknown. This study aimed to elucidate sperm whale alloCare, in particular: who escorts whose calf and whether or not calves suckle from nonparent females. Using photo identification and behavioral calf follows, we examined patterns of adult‐infant interactions for 23 sperm whale calves in the Sargasso and Caribbean Seas. Although multiple individuals of both sexes escorted the calves, the system of escorting differed between the 2 sites. For all calves studied in the Caribbean, we found that 1 female provided most of the alloCare but did not nurse the calf, whereas in the Sargasso, multiple females provided Care for, and nursed, the young. We discuss differences between populations that may have resulted in the observed differences in these 2 systems of alloCare and how these findings fit with current hypotheses on the roles of kin selection and reciprocal altruism in cooperative Care in mammals. Key words: Alloparental Care, allosuckling, cetaceans, escort, mother‐calf, Physeter macrocephalus, social structure, sperm whale. [Behav Ecol]
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Babysitting, dive synchrony, and indications of Alloparental Care in sperm whales
Behavioral Ecology and Sociobiology, 1996Co-Authors: Hal WhiteheadAbstract:Young sperm whales (Physeter macrocephalus) serially accompany different members of their social group at the surface while the majority of the group is foraging at depth. The presence of a nearby larger whale is likely to increase the survival prospects of the young animal. In studies off the Galapagos Islands, first-year calves were less likely to be seen at the surface alone than were larger whales, and groups containing calves showed less synchronous diving behaviour – shorter intervals with no larger whales at the surface – than those without calves. This difference in diving synchrony was not solely the result of behaviour by individuals assumed to be the mothers of calves (as they spent a disproportionate amount of time accompanying them). Thus babysitting in sperm whales seems to be a form of Alloparental Care. Its benefit may have been an important factor in the evolution of sociality in female sperm whales.
Carsten Schradin - One of the best experts on this subject based on the ideXlab platform.
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Corticosterone Levels Correlate With Alloparental Care in a Sex-Dependent Manner in African Striped Mice, Rhabdomys pumilio
Ethology, 2014Co-Authors: Julien Raynaud, Carsten SchradinAbstract:Alloparental Care of non-breeders is the main characteristic of cooperatively breeding species. While many studies have contributed to the understanding of the evolutionary reasons why individuals provide Care to young that are not their own offspring, the variables influencing and causing Alloparental Care are less understood. We tested in African striped mice (Rhabdomys pumilio) whether age, sex, testosterone and corticosterone were correlated with Alloparental Care of non-breeding helpers. We studied 11 family groups under controlled conditions in the laboratory, each with two juvenile and two adult helpers, one being male and one being female in each age category. We predicted male helpers to show more Alloparental Care than female helpers, as males are the dispersing sex and might thus have to pay for staying. We also expected adult helpers to show more Alloparental Care than juvenile helpers and both corticosterone and testosterone to correlate negatively with Alloparental Care. We found high levels of Alloparental Care in non-breeding striped mice, which spent a significant amount of time in the nest, huddling and licking pups. There was neither a difference between the sexes nor between age categories (although both factors were significant in interaction terms), indicating either low costs and/or high benefits of Alloparental Care. Mothers showed significantly more Care than helpers, and fathers showed similar levels of parental Care as mothers but not significantly more than helpers. Although testosterone levels differed significantly between helpers of different age and sex, with adult male helpers showing the highest levels, we did not find any relationships between testosterone and the amount of Alloparental Care. Corticosterone levels were negatively correlated with Alloparental Care, and these effects were modulated by the sex and the age of helpers. In females, less Alloparental Care was shown with increasing corticosterone levels, while in males, the relationship was positive. Also, younger individuals with lower corticosterone levels showed more Alloparental Care than older individuals with low corticosterone levels. In sum, Alloparental Care is well developed in male and female non-breeding helpers of striped mice, both in adult and juvenile helpers, but independently of testosterone, with corticosterone showing an age- and sex-specific relationship with Alloparental Care.
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Experimental increase of testosterone increases boldness and decreases anxiety in male African striped mouse helpers
Physiology & behavior, 2014Co-Authors: Julien Raynaud, Carsten SchradinAbstract:Males of many species can adjust their behaviors to environmental conditions by changing reproductive tactics. Testosterone surges in adult breeding males typically inhibit the expression of paternal Care while facilitating the expression of aggression during environmental changes. Similarly, in non-breeding philopatric males of cooperatively breeding species, up-regulation of testosterone may inhibit Alloparental Care while facilitating dispersal, i.e. males might become bolder and more explorative. We tested this hypothesis in philopatric male African striped mice, Rhabdomys pumilio. Striped mouse males can either remain in their natal groups providing Alloparental Care or they can disperse seeking mating opportunities. Compared to philopatric males, dispersed males typically show higher testosterone levels and lower corticosterone levels, and more aggression toward pups and same sex conspecifics. We experimentally increased the testosterone levels of the philopatric males kept in their family groups when pups were present. Testosterone-treated males did not differ significantly from control males in Alloparental Care and in aggression toward same-sex conspecifics. Compared to the control males, testosterone treated males were bolder, more active, and less anxious; they also showed lower corticosterone levels. The philopatric males were sensitive to our testosterone treatment for dispersal- and anxiety-like behavior but insensitive for social behaviors. Our results suggest a role of testosterone in dispersal.
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Parental and Alloparental Care in a Polygynous Mammal
Journal of Mammalogy, 2009Co-Authors: Melanie Schubert, Neville Pillay, Carsten SchradinAbstract:We studied maternal, paternal, and Alloparental Care in striped mice (Rhabdomys pumilio), which nest and breed communally in the succulent karoo, South Africa. A total of 18 triads, each consisting of 2 adult female littermates and an unfamiliar adult male, were set up under natural weather conditions. We expected that relationships within captive triads that breed communally would be egalitarian, and that all individuals would participate in the rearing of offspring, but we assumed that the degree of Caregiving behavior would vary between mothers, fathers, and alloparents, because individuals obtain different fitness benefits. Social interactions in the triads were predominantly amicable and in the majority of triads, both females produced litters in a communal nest. All 3 adults in a triad participated in Care of the offspring, with mothers spending 43%, fathers 26%, and alloparents 24% of observations in Caregiving activities. Our results indicate that sisters can form stable cooperative relationships, but members of a communal nest allocate their Caregiving to individual offspring according to potential trade-offs between direct and indirect fitness benefits. Large amounts of paternal Care can occur in a polygynous species, which contrasts with the common belief that paternal Care is a characteristic of monogamy.
Sandra M. Rehan - One of the best experts on this subject based on the ideXlab platform.
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The price of insurance: costs and benefits of worker production in a facultatively social bee
Behavioral Ecology, 2017Co-Authors: Wyatt A. Shell, Sandra M. RehanAbstract:Selection on traits that maximize maternal fitness represents a recurrent mechanism underlying early evolutionary transitions towards social organization. We use genetic and demographic data to perform a cost-benefit analysis comparing alternative reproductive strategies in a bee capable of both subsocial and social nesting. We find that, while Alloparental Care provides few fitness benefits for worker daughters, social nesting is an advantageous strategy by way of assured fitness returns to social mothers.
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At the brink of eusociality: transcriptomic correlates of worker behaviour in a small carpenter bee
BMC evolutionary biology, 2014Co-Authors: Sandra M. Rehan, Ali J. Berens, Amy L. TothAbstract:Background There is great interest in understanding the genomic underpinnings of social evolution, in particular, the evolution of eusociality (caste-containing societies with non-reproductives that Care for siblings). Subsociality is a key precursor for the evolution of eusociality and characterized by prolonged parental Care and parent-offspring interaction. Here, we provide the first transcriptomic data for the small carpenter bee, Ceratina calcarata. This species is of special interest because it is subsocial and in the same family as the highly eusocial honey bee, Apis mellifera. In addition, some C. calcarata females demonstrate Alloparental Care without reproduction, which provides a unique opportunity to study worker behaviour in a non-eusocial species.
Julien Raynaud - One of the best experts on this subject based on the ideXlab platform.
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Corticosterone Levels Correlate With Alloparental Care in a Sex-Dependent Manner in African Striped Mice, Rhabdomys pumilio
Ethology, 2014Co-Authors: Julien Raynaud, Carsten SchradinAbstract:Alloparental Care of non-breeders is the main characteristic of cooperatively breeding species. While many studies have contributed to the understanding of the evolutionary reasons why individuals provide Care to young that are not their own offspring, the variables influencing and causing Alloparental Care are less understood. We tested in African striped mice (Rhabdomys pumilio) whether age, sex, testosterone and corticosterone were correlated with Alloparental Care of non-breeding helpers. We studied 11 family groups under controlled conditions in the laboratory, each with two juvenile and two adult helpers, one being male and one being female in each age category. We predicted male helpers to show more Alloparental Care than female helpers, as males are the dispersing sex and might thus have to pay for staying. We also expected adult helpers to show more Alloparental Care than juvenile helpers and both corticosterone and testosterone to correlate negatively with Alloparental Care. We found high levels of Alloparental Care in non-breeding striped mice, which spent a significant amount of time in the nest, huddling and licking pups. There was neither a difference between the sexes nor between age categories (although both factors were significant in interaction terms), indicating either low costs and/or high benefits of Alloparental Care. Mothers showed significantly more Care than helpers, and fathers showed similar levels of parental Care as mothers but not significantly more than helpers. Although testosterone levels differed significantly between helpers of different age and sex, with adult male helpers showing the highest levels, we did not find any relationships between testosterone and the amount of Alloparental Care. Corticosterone levels were negatively correlated with Alloparental Care, and these effects were modulated by the sex and the age of helpers. In females, less Alloparental Care was shown with increasing corticosterone levels, while in males, the relationship was positive. Also, younger individuals with lower corticosterone levels showed more Alloparental Care than older individuals with low corticosterone levels. In sum, Alloparental Care is well developed in male and female non-breeding helpers of striped mice, both in adult and juvenile helpers, but independently of testosterone, with corticosterone showing an age- and sex-specific relationship with Alloparental Care.
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Experimental increase of testosterone increases boldness and decreases anxiety in male African striped mouse helpers
Physiology & behavior, 2014Co-Authors: Julien Raynaud, Carsten SchradinAbstract:Males of many species can adjust their behaviors to environmental conditions by changing reproductive tactics. Testosterone surges in adult breeding males typically inhibit the expression of paternal Care while facilitating the expression of aggression during environmental changes. Similarly, in non-breeding philopatric males of cooperatively breeding species, up-regulation of testosterone may inhibit Alloparental Care while facilitating dispersal, i.e. males might become bolder and more explorative. We tested this hypothesis in philopatric male African striped mice, Rhabdomys pumilio. Striped mouse males can either remain in their natal groups providing Alloparental Care or they can disperse seeking mating opportunities. Compared to philopatric males, dispersed males typically show higher testosterone levels and lower corticosterone levels, and more aggression toward pups and same sex conspecifics. We experimentally increased the testosterone levels of the philopatric males kept in their family groups when pups were present. Testosterone-treated males did not differ significantly from control males in Alloparental Care and in aggression toward same-sex conspecifics. Compared to the control males, testosterone treated males were bolder, more active, and less anxious; they also showed lower corticosterone levels. The philopatric males were sensitive to our testosterone treatment for dispersal- and anxiety-like behavior but insensitive for social behaviors. Our results suggest a role of testosterone in dispersal.
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Physiological and Behavioural Flexibility in African Striped Mice: Testosterone and Environmental Influences
2013Co-Authors: Julien RaynaudAbstract:Flexibility – reversible phenotypic changes in physiology, morphology, and / or behaviour – has been extensively studied in the framework of alternative reproductive tactics (ARTs). A reproductive tactic is a phenotype that results from a strategy – a decision rule based on genetic program. The relative plasticity hypothesis states that environmentally-induced hormonal changes cause the development of one out several possible ARTs. However, causality between hormones and ARTs has been poorly studied. Further, it is important to determine which environmental factors influence hormonal changes in males of different ARTs to determine in how far these hormonal changes are flexible. In this thesis, I experimentally studied the role of testosterone in causing physiological, morphological, and behavioural differences between two alternative reproductive tactics in male African striped mice, Rhabdomys pumilio: 1) group-living helpers showing Alloparental Care, low testosterone levels, and high corticosterone levels. 2) solitary-living roamers showing no parental Care, high testosterone levels, and low corticosterone levels. Finally, I tested the flexibility of prolactin secretion as prolactin may play a role in the regulation of ARTs. For this, I studied the role of photoperiod and food availability in regulating prolactin levels of paternal dominant breeding males. In chapter 1 I studied which factors correlate with Alloparental Care. For the first time I demonstrated that both male and female, juvenile and adult philopatrics show extensive helping behaviour (14.7 % of their time). Corticosterone levels correlated with Alloparental Care in an age- and sex-dependent manner. Natural variation of testosterone levels between helpers did not correlate with Alloparental Care, suggesting that changes in Alloparental Care after the tactic switch are not caused by testosterone. In chapter 2, I tested whether an experimental increase of testosterone in male group living helpers influenced Alloparental Care and dispersal-like behaviours. An experimental increase of testosterone in male group-living helpers did not reduce Alloparental Care nor aggressive behaviour, but increased boldness, decreased anxiety, and lowered basal corticosterone levels. In the field, exogenous testosterone did not cause dispersal, but it caused male group-living helpers to expand their home ranges (chapter 3). I suggested that an increase of testosterone facilitate dispersal by reducing stress reactivity (low corticosterone levels and low anxiety). Exogenous testosterone also induced sexual maturation and spermatogenesis – testosterone-treated male group-living helpers became scrotal and showed larger testes and epididymis (chapter 3). Thus, I suggested that a quick increase of testosterone levels is an important event during the tactic switch to cause necessary physiological, morphological, and behavioural changes in group-living helpers to disperse and become solitary-living roamers. In chapter 4 I showed that free-ranging paternal dominant breeding males showed higher prolactin levels when they were breeding compared to the non-breeding season, independently whether this was during spring (increase of photoperiod) or during summer, i.e. normal non-breeding season (decrease of photoperiod). Food availability correlated with prolactin levels, suggesting that cues related to food availability may regulate prolactin levels. As paternal dominant breeding males have higher reproductive success than males following an alternative reproductive tactic (i.e. group-living helpers and solitary-living roamers), flexibility in prolactin secretion seems adaptive. My thesis demonstrated that testosterone plays an important role in physiological, morphological and behavioural differences between males of different ARTs in African striped mice. I also showed that the role of environmental factors (e.g. food availability) is crucial in hormonal flexibility (prolactin levels). Thus, studies from the African striped mouse suggest a complex relationship between hormonal and environmental factors in the regulation of ARTs. For future studies, I discussed how to integrate environmental factors in the behavioural endocrinology approach to study proximate mechanisms of ARTs.
Karen L. Bales - One of the best experts on this subject based on the ideXlab platform.
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revisiting paternal absence female Alloparental replacement of fathers recovers partner preference formation in female but not male prairie voles microtus ochrogaster
Developmental Psychobiology, 2020Co-Authors: Forrest Dylan Rogers, Karen L. BalesAbstract:In prairie voles (Microtus ochrogaster), biparental Care of offspring is typical, and paternal absence in the pre-weaning development of offspring alters biobehavioral development. We sought to determine whether this altered development is due to the absence of specific paternal qualities or a general reduction in pup-directed Care. We compared the biobehavioral development of pups reared under conditions of biparental (BPC), maternal-plus-Alloparental (MPA; i.e., mother and older sister), and maternal only (MON) Care. Older sisters provided a quantity of Care equal to or greater than that of fathers. Growth rate and developmental milestones were unaffected by family composition, with the exception of earlier fur growth in MON conditions. In adulthood, we tested behaviors on an elevated plus maze, spontaneous Alloparental Care, and partner preference formation. We found no significant differences on the elevated plus maze and only marginal differences in Alloparental Care. While both female and male MON individuals showed deficits in partner preference formation, MPA females showed typical partner preference formation. However, the Alloparental substitution of fathers was not sufficient for the typical development of partner preference formation in males. We conclude that paternal Care plays a differentially important role in the social development of female and male prairie vole offspring.
