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A calcitonin receptor-expressing subregion of the medial preoptic area is involved in alloparental tolerance in common marmosets. Commun Biol 2022; 5:1243. [PMID: 36411342 PMCID: PMC9678893 DOI: 10.1038/s42003-022-04166-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 10/25/2022] [Indexed: 11/23/2022] Open
Abstract
Like humans, common marmoset monkeys utilize family cooperation for infant care, but the neural mechanisms underlying primate parental behaviors remain largely unknown. We investigated infant care behaviors of captive marmosets in family settings and caregiver-infant dyadic situations. Marmoset caregivers exhibited individual variations in parenting styles, comprised of sensitivity and tolerance toward infants, consistently across infants, social contexts and multiple births. Seeking the neural basis of these parenting styles, we demonstrated that the calcitonin receptor-expressing neurons in the marmoset medial preoptic area (MPOA) were transcriptionally activated during infant care, as in laboratory mice. Further, site-specific neurotoxic lesions of this MPOA subregion, termed the cMPOA, significantly reduced alloparental tolerance and total infant carrying, while sparing general health and other social or nonsocial behaviors. These results suggest that the molecularly-defined neural site cMPOA is responsible for mammalian parenting, thus provide an invaluable model to study the neural basis of parenting styles in primates.
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2
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Gilbert JD, Rossiter SJ, Bennett NC, Faulkes CG. The elusive role of prolactin in the sociality of the naked mole-rat. Horm Behav 2022; 143:105196. [PMID: 35597054 DOI: 10.1016/j.yhbeh.2022.105196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 04/13/2022] [Accepted: 05/05/2022] [Indexed: 12/01/2022]
Abstract
Despite decades of research into the evolutionary drivers of sociality, we know relatively little about the underlying proximate mechanisms. Here we investigate the potential role of prolactin in the highly social naked mole-rat. Naked mole-rats live in large social groups but, only a small number of individuals reproduce. The remaining non-breeders are reproductively suppressed and contribute to burrow maintenance, foraging, and allo-parental care. Prolactin has well-documented links with reproductive timing and parental behaviour, and the discovery that non-breeding naked mole-rats have unusually high prolactin levels has led to the suggestion that prolactin may help maintain naked mole-rat sociality. To test this idea, we investigated whether urinary prolactin was correlated with cooperative behaviour and aggression. We then administered the prolactin-suppressing drug Cabergoline to eight female non-breeders for eight weeks and assessed the physiology and behaviour of the animals relative to controls. Contrary to the mammalian norm, and supporting previous findings for plasma, we found non-breeders had elevated urinary prolactin concentrations that were similar to breeding females. Further, prolactin levels were higher in heavier, socially dominant non-breeders. Urinary prolactin concentrations did not explain variation in working behaviour or patterns of aggression. Furthermore, females receiving Cabergoline did not show any behavioural or hormonal (progesterone) differences, and urinary prolactin did not appear to be suppressed in individuals receiving Cabergoline. While the results add to the relatively limited literature experimentally manipulating prolactin to investigate its role in reproduction and behaviour, they fail to explain why prolactin levels are high in non-breeding naked mole-rats, or how female non-breeding phenotypes are maintained.
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Affiliation(s)
- James D Gilbert
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom of Great Britain and Northern Ireland.
| | - Stephen J Rossiter
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom of Great Britain and Northern Ireland
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Christopher G Faulkes
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom of Great Britain and Northern Ireland.
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3
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Cunha-Saraiva F, Martins RST, Power DM, Balshine S, Schaedelin FC. Galanin and prolactin expression in relation to parental care in two sympatric cichlid species from Lake Tanganyika. Gen Comp Endocrinol 2021; 309:113785. [PMID: 33862047 DOI: 10.1016/j.ygcen.2021.113785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 03/23/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Our understanding of the hormonal mechanisms underlying parental care mainly stems from research on species with uniparental care. Far less is known about the physiological changes underlying motherhood and fatherhood in biparental caring species. Here, using two biparental caring cichlid species (Neolamprologus caudopunctatus and Neolamprologus pulcher), we explored the relative gene-expression levels of two genes implicated in the control of parental care, galanin (gal) and prolactin (prl). We investigated whole brain gene expression levels in both, male and female caring parents, as well as in non-caring individuals of both species. Caring males had higher prl and gal mRNA levels compared to caring females in both fish species. Expression of gal was highest when young were mobile and the need for parental defense was greatest and gal was lowest during the more stationary egg tending phase in N. caudopunctatus. The onset of parenthood was associated with lower expression of prl and higher expression of gal in N. pulcher, but this pattern was not observed in N. caudopunctatus. Our study demonstrates that gal gene expression is correlated with changes in parental care in two biparental cichlid species and extends both knowledge and taxonomic coverage of the possible neurogenetic mechanisms underlying parental care.
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Affiliation(s)
- Filipa Cunha-Saraiva
- Konrad Lorenz Institute of Ethology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna, Austria.
| | - Rute S T Martins
- Centre of Marine Sciences (CCMAR), University of Algarve, Faro, Portugal
| | - Deborah M Power
- Centre of Marine Sciences (CCMAR), University of Algarve, Faro, Portugal
| | - Sigal Balshine
- Aquatic Behavioural Ecology Laboratory, Department of Psychology, Neuroscience, & Behaviour, McMaster University, Ontario, Canada
| | - Franziska C Schaedelin
- Konrad Lorenz Institute of Ethology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna, Austria
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4
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Coen CW, Bennett NC, Holmes MM, Faulkes CG. Neuropeptidergic and Neuroendocrine Systems Underlying Eusociality and the Concomitant Social Regulation of Reproduction in Naked Mole-Rats: A Comparative Approach. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:59-103. [PMID: 34424513 DOI: 10.1007/978-3-030-65943-1_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The African mole-rat family (Bathyergidae) includes the first mammalian species identified as eusocial: naked mole-rats. Comparative studies of eusocial and solitary mole-rat species have identified differences in neuropeptidergic systems that may underlie the phenomenon of eusociality. These differences are found in the oxytocin, vasopressin and corticotrophin-releasing factor (CRF) systems within the nucleus accumbens, amygdala, bed nucleus of the stria terminalis and lateral septal nucleus. As a corollary of their eusociality, most naked mole-rats remain pre-pubertal throughout life because of the presence of the colony's only reproductive female, the queen. To elucidate the neuroendocrine mechanisms that mediate this social regulation of reproduction, research on the hypothalamo-pituitary-gonadal axis in naked mole-rats has identified differences between the many individuals that are reproductively suppressed and the few that are reproductively mature: the queen and her male consorts. These differences involve gonadal steroids, gonadotrophin-releasing hormone-1 (GnRH-1), kisspeptin, gonadotrophin-inhibitory hormone/RFamide-related peptide-3 (GnIH/RFRP-3) and prolactin. The comparative findings in eusocial and solitary mole-rat species are assessed with reference to a broad range of studies on other mammals.
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Affiliation(s)
- Clive W Coen
- Reproductive Neurobiology, Division of Women's Health, Faculty of Life Sciences & Medicine, King's College London, London, UK.
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Melissa M Holmes
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada.,Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada.,Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
| | - Christopher G Faulkes
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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5
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Huang J, Cheng X, Zhang S, Chang L, Li X, Liang Z, Gong N. Having Infants in the Family Group Promotes Altruistic Behavior of Marmoset Monkeys. Curr Biol 2020; 30:4047-4055.e3. [PMID: 32822603 DOI: 10.1016/j.cub.2020.07.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 05/05/2020] [Accepted: 07/14/2020] [Indexed: 11/24/2022]
Abstract
The common marmoset (Callithrix jacchus) has attracted much attention as a useful model for studying social behaviors [1-3]. They naturally live in a monogamous family group and exhibit cooperative breeding [4], in which parents and older siblings help to carry infants less than 2 months old [5-7]. Marmoset parents also transfer foods to their offspring, a process that may help them learn the food diet [8]. Furthermore, marmosets show spontaneous altruistic behaviors, such as providing food to non-reciprocating and genetically unrelated individuals [9]. These social habits indicate that marmosets may be a useful non-human primate model for studying parenting and altruistic behaviors, as well as underlying neural mechanisms. Using a novel rescue paradigm, we found that marmoset parents and older siblings showed strong motivation to rescue trapped young infants but not juvenile marmosets beyond 2 months of age, and infant calls alone could trigger these parents' rescue behaviors. The marmoset parents showed little rescue of each other, but young infants or infant calls could also induce such parents' mutual rescue. Moreover, all these infant- and mate-rescue behaviors depended on currently having young infants in the family group. Functional MRI studies on awake adult marmosets showed that calls from young infants, but not juvenile marmosets, elicited a large-scale activation of specific brain areas including auditory and insular cortices, and such activation was absent in marmosets not living with infants. Thus, such infant-induced modification of neural activity offers a window for examining the neural basis of altruistic behaviors in marmoset monkeys.
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Affiliation(s)
- Junfeng Huang
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaochun Cheng
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Shikun Zhang
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Liangtang Chang
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xuebo Li
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhifeng Liang
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 201210, China.
| | - Neng Gong
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 201210, China.
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Schradin C, Vuarin P, Rimbach R. The neoteny-helper hypothesis: When to expect and when not to expect endocrine mechanisms to regulate allo-parental care? Physiol Behav 2018; 193:127-134. [DOI: 10.1016/j.physbeh.2017.12.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 12/06/2017] [Accepted: 12/06/2017] [Indexed: 11/15/2022]
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7
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Why help? Relationship quality, not strategic grooming predicts infant-care in group-living marmosets. Physiol Behav 2018; 193:108-116. [PMID: 29730031 DOI: 10.1016/j.physbeh.2018.02.050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 02/24/2018] [Accepted: 02/26/2018] [Indexed: 11/20/2022]
Abstract
Cooperatively breeding common marmosets raise their infants with the help of other adult group members, but individual care-taking contribution can vary considerably. We tested four hypotheses that may explain this variation within marmoset family groups. The pay-for-help hypothesis argues that allogrooming is used strategically by parents to pay helpers for helping. The pay-for-infant-access hypothesis claims that helpers use allogrooming as payment for infant-access. The intrinsic predisposition hypothesis suggests that more affiliative individuals are also more motivated for infant-care, and the relationship quality hypothesis that individuals involved in highly affiliative relationships with main caregivers contribute more to infant-care. To test these hypotheses, we followed five marmoset family groups over a total of eight reproductive cycles, and quantified affiliative behavior, infant-carrying, and food sharing over six to 12 weeks around infant-birth. We found no evidence for either the pay-for-help or pay-for-infant-access hypotheses nor did intrinsic prosocial predisposition determine individual infant-care. Mutual dyadic affiliation, however, was positively linked to infant-carrying and food sharing in female and male breeders and in male helpers. This suggests that cooperation during infant-care is mediated by relationship quality rather than strategic grooming in marmosets. Overall, these results may also contribute to a better understanding of cooperation in humans.
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8
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Barbosa MN, Mota MTDS, Barbosa MN. The effect of infant vocalization in alloparental responsiveness of common marmosets (Callithrix jacchus). Am J Primatol 2017. [PMID: 28631840 DOI: 10.1002/ajp.22682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Among mammals, alloparental care can be influenced by hormones as well as by previous experience and sensory stimuli from the infants, such as sight and sound, smell, and physical contact with the infant. To determine the responsiveness of common marmoset (Callithrix jacchus) nonreproductive females and males with and without previous experience in caretaking to infant sensory cues, we exposed 12 females and 12 males to vocalization recordings for 10 min under two conditions: (1) exposure to adult conspecific vocalization recordings, and (2) exposure to infant vocalization recordings. We recorded the frequency of approach toward the sound source, the time spent near it and locomotion frequency of males and females in the cage under both conditions. Blood samples were collected after each test for cortisol measuring by EIA method. The infant vocalization affects the behavioral and hormonal responses of males and females of common marmosets. The animals approached and spent more time near the sound source and showed an increase in locomotion during infant vocalization exposure compared to the adult vocalization. However, there was no significant difference in the behavioral response of animals when previous experience and the sex were taken into account. In both sexes, cortisol levels were significantly higher following infant vocalization exposure compared to the adult vocalization. These findings suggest that the infant vocalization appears to be an effective cue that facilitates the approach of the caregiver and maintaining their responsiveness and that the cortisol seems to be important for alertness to sensory stimuli, modulating their motivation to interact with the infant.
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Affiliation(s)
- Maricele Nascimento Barbosa
- Departamento de Fisiologia, Centro de Biociências, UFRN, Caixa Postal 1511, Campus Universitário, Natal-RN, Brazil
| | - Maria Teresa da Silva Mota
- Departamento de Fisiologia, Centro de Biociências, UFRN, Caixa Postal 1511, Campus Universitário, Natal-RN, Brazil
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9
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Behringer V, Deschner T. Non-invasive monitoring of physiological markers in primates. Horm Behav 2017; 91:3-18. [PMID: 28202354 DOI: 10.1016/j.yhbeh.2017.02.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 01/26/2017] [Accepted: 02/01/2017] [Indexed: 12/21/2022]
Abstract
The monitoring of endocrine markers that inform about an animal's physiological state has become an invaluable tool for studying the behavioral ecology of primates. While the collection of blood samples usually requires the animal to be caught and immobilized, non-invasively collected samples of saliva, urine, feces or hair can be obtained without any major disturbance of the subject of interest. Such samples enable repeated collection which is required for matching behavioral information over long time periods with detailed information on endocrine markers. We start our review by giving an overview of endocrine and immune markers that have been successfully monitored in relation to topics of interest in primate behavioral ecology. These topics include reproductive, nutritional and health status, changes during ontogeny, social behavior such as rank relationships, aggression and cooperation as well as welfare and conservation issues. We continue by explaining which hormones can be measured in which matrices, and potential problems with measurements. We then describe different methods of hormone measurements and address their advantages and disadvantages. We finally emphasize the importance of thorough validation procedures when measuring a specific hormone in a new species or matrix.
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Affiliation(s)
- Verena Behringer
- Max Planck Institute for Evolutionary Anthropology, Department of Primatology, Deutscher Platz 6, D-04103 Leipzig, Germany.
| | - Tobias Deschner
- Max Planck Institute for Evolutionary Anthropology, Department of Primatology, Deutscher Platz 6, D-04103 Leipzig, Germany
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10
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Finkenwirth C, Martins E, Deschner T, Burkart JM. Oxytocin is associated with infant-care behavior and motivation in cooperatively breeding marmoset monkeys. Horm Behav 2016; 80:10-18. [PMID: 26836769 DOI: 10.1016/j.yhbeh.2016.01.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 12/22/2015] [Accepted: 01/29/2016] [Indexed: 01/26/2023]
Abstract
The neurohormone oxytocin (OT) is positively involved in the regulation of parenting and social bonding in mammals, and may thus also be important for the mediation of alloparental care. In cooperatively breeding marmosets, infants are raised in teamwork by parents and adult and sub-adult non-reproductive helpers (usually older siblings). Despite high intrinsic motivation, which may be mediated by hormonal priming, not all individuals are always equally able to contribute to infant-care due to competition among care-takers. Among the various care-taking behaviors, proactive food sharing may reflect motivational levels best, since it can be performed ad libitum by several individuals even if competition among surplus care-takers constrains access to infants. Our aim was to study the link between urinary OT levels and care-taking behaviors in group-living marmosets, while taking affiliation with other adults and infant age into account. Over eight reproductive cycles, 26 individuals were monitored for urinary baseline OT, care-taking behaviors (baby-licking, -grooming, -carrying, and proactive food sharing), and adult-directed affiliation. Mean OT levels were generally highest in female breeders and OT increased significantly in all individuals after birth. During early infancy, high urinary OT levels were associated with increased infant-licking but low levels of adult-affiliation, and during late infancy, with increased proactive food sharing. Our results show that, in marmoset parents and alloparents, OT is positively involved in the regulation of care-taking, thereby reflecting the changing needs during infant development. This particularly included behaviors that are more likely to reflect intrinsic care motivation, suggesting a positive link between OT and motivational regulation of infant-care.
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Affiliation(s)
- Christa Finkenwirth
- Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| | - Eloisa Martins
- Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Tobias Deschner
- Max-Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Judith M Burkart
- Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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11
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Storey AE, Ziegler TE. Primate paternal care: Interactions between biology and social experience. Horm Behav 2016; 77:260-71. [PMID: 26253726 PMCID: PMC4968077 DOI: 10.1016/j.yhbeh.2015.07.024] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 11/15/2022]
Abstract
This article is part of a Special Issue "Parental Care".We review recent research on the roles of hormones and social experiences on the development of paternal care in humans and non-human primates. Generally, lower concentrations of testosterone and higher concentrations of oxytocin are associated with greater paternal responsiveness. Hormonal changes prior to the birth appear to be important in preparation for fatherhood and changes after the birth are related to how much time fathers spend with offspring and whether they provide effective care. Prolactin may facilitate approach and the initiation of infant care, and in some biparental non-human primates, it affects body mass regulation. Glucocorticoids may be involved in coordinating reproductive and parental behavior between mates. New research involving intranasal oxytocin and neuropeptide receptor polymorphisms may help us understand individual variation in paternal responsiveness. This area of research, integrating both biological factors and the role of early and adult experience, has the potential to suggest individually designed interventions that can strengthen relationships between fathers and their partners and offspring.
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Affiliation(s)
- Anne E Storey
- Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X9, Canada; Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X9, Canada.
| | - Toni E Ziegler
- National Primate Research Center University of Wisconsin-Madison, Madison, WI 53715, USA
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12
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Snowdon CT, Ziegler TE. Variation in prolactin is related to variation in sexual behavior and contact affiliation. PLoS One 2015; 10:e0120650. [PMID: 25799436 PMCID: PMC4370565 DOI: 10.1371/journal.pone.0120650] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 01/26/2015] [Indexed: 11/18/2022] Open
Abstract
Prolactin is associated with both maternal and paternal care and appears important in developing a bond between parent and infant. In contrast with oxytocin, another hormone important in infant care, there is scant information on the role of prolactin in maintaining adult heterosexual relationships. We present here the first results demonstrating a relationship between prolactin levels and sexual and contact affiliation behavior in a pair-bonded species. We studied cotton-top tamarins, a socially-monogamous, cooperatively-breeding primate. We measured chronic urinary prolactin levels over a four week period to include the entire female ovulatory cycle and correlated prolactin levels in males and females with simultaneous measures of contact affiliation and sexual behavior. Current mothers who were no longer nursing displayed lower amounts of sexual behavior and proximity than non-breeding females and also had marginally lower levels of prolactin. The prolactin levels of males and females were similar within pairs, and variation in prolactin levels for both sexes was explained both by the amount of sexual behavior and contact affiliation. The results parallel a previous study that compared oxytocin levels with sociosexual behavior in the same species, and supports the hypothesis that both prolactin and oxytocin are involved in pair-bonding as well as in infant care.
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Affiliation(s)
- Charles T Snowdon
- Department of Psychology, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail:
| | - Toni E Ziegler
- Wisconsin National Primate Research Center, Madison, Wisconsin, United States of America
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13
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Saito A. The marmoset as a model for the study of primate parental behavior. Neurosci Res 2015; 93:99-109. [PMID: 25575642 DOI: 10.1016/j.neures.2014.12.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/19/2014] [Accepted: 12/24/2014] [Indexed: 01/27/2023]
Abstract
Parental behavior is important for the development of mammalian offspring. Research on the mechanisms underlying parental behavior, however, has been largely restricted to rodent models. As a consequence, although research on parent-infant relationships has been conducted using macaque monkeys for more than half a century, little is known about the neural mechanisms and brain regions associated with such behaviors in primates. This article reviews parental behavior and its endocrinological mechanisms in marmosets and tamarins, both cooperative breeders in the callitrichid family, and compares these findings with studies of macaque monkeys. The paper examines the similarities and differences between marmosets and humans, and suggests the possibility that marmosets can be a model for future studies of the neural underpinnings and endocrinology underlying human parental behavior.
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Affiliation(s)
- Atsuko Saito
- Department of Cognitive and Behavioral Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
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14
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Barbosa MN, Mota MTDS. Do newborn vocalizations affect the behavioral and hormonal responses of nonreproductive male common marmosets (Callithrix jacchus)? Primates 2014; 55:293-302. [PMID: 24394953 DOI: 10.1007/s10329-013-0404-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 12/24/2013] [Indexed: 10/25/2022]
Abstract
Parental care in mammals is influenced by sensory stimuli from infants, such as sight and sound, and by changes in the hormone levels of caretakers. To determine the responsiveness of common marmoset (Callithrix jacchus) adult males with and without previous experience in caretaking to newborn sensory cues, we exposed twelve males to infant vocalization recordings and assessed their hormonal and behavioral responses. Males were placed in the testing cage for 10 min under two conditions: (a) control condition (exposure to adult conspecific vocalization recordings), and (b) experimental condition (exposure to infant vocalization recordings). We recorded the frequency of approach towards the sound source, the time spent near it and locomotion frequency of males in the cage under both conditions. Blood samples were collected after each test for cortisol, measured by the enzyme immunoassay method. Infant vocalization affects the behavioral and hormonal responses of non-reproductive male common marmosets. All males approached and spent more time near the sound source and showed an increase in locomotion during infant vocalization exposure compared to the control condition. Successive exposure to infant vocalization increased the responsiveness in inexperienced males. Cortisol levels were significantly higher following infant vocalization exposure compared to the control condition. These findings support the assumption that sound stimuli from the newborn are critical in initiating and maintaining caretaker responsiveness and that cortisol seems to be important for alertness to sensory stimuli, modulating their motivation to interact with infants.
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Affiliation(s)
- Maricele Nascimento Barbosa
- Departamento de Fisiologia, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Campus Universitário, Caixa Postal 1511, Natal, RN, 59078-970, Brazil.
| | - Maria Teresa da Silva Mota
- Departamento de Fisiologia, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Campus Universitário, Caixa Postal 1511, Natal, RN, 59078-970, Brazil
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15
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Storey AE, Noseworthy DE, Delahunty KM, Halfyard SJ, McKay DW. The effects of social context on the hormonal and behavioral responsiveness of human fathers. Horm Behav 2011; 60:353-61. [PMID: 21767539 DOI: 10.1016/j.yhbeh.2011.07.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 06/21/2011] [Accepted: 07/01/2011] [Indexed: 11/25/2022]
Abstract
We tested first-time fathers with their 22-month old toddlers to determine whether social context variables such as pre-test absence from the child and presence of the mother affected physiological measures associated with paternal responsiveness. Heart rate and blood pressure readings as well as blood samples to determine prolactin, testosterone and cortisol levels were taken before and after the 30-min father-toddler interactions. Fathers were tested on a day when they were away from their child for several hours before testing ('without-child' day) and on another day where they remained with their child throughout the day ('with-child' day). Most measures decreased over the 30-min test period but relative decreases were context-dependent. Men maintained higher prolactin levels when they were away from their children longer before testing on the 'without-child' day. Cortisol levels decreased during both tests and they decreased more on the 'with-child' day for men who had spent more time alone with their toddler before the test. Heart-rate and diastolic (but not systolic) blood pressure decreased more on the 'with-child' day than on the 'without-child' day. Fathers' testosterone levels decreased when their partners were less involved in the interactions. Compared to men with high responsiveness ratings on both days, men whose responsiveness increased after being away from their child on the 'without-child' day maintained higher systolic blood pressure and had a greater decrease in testosterone levels. We conclude that context may be more important in determining fathers' physiological responses to child contact than has previously been appreciated, particularly for some individuals.
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Affiliation(s)
- Anne E Storey
- Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada.
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16
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Saltzman W, Maestripieri D. The neuroendocrinology of primate maternal behavior. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:1192-204. [PMID: 20888383 PMCID: PMC3072435 DOI: 10.1016/j.pnpbp.2010.09.017] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 09/23/2010] [Accepted: 09/24/2010] [Indexed: 10/19/2022]
Abstract
In nonhuman primates and humans, similar to other mammals, hormones are not strictly necessary for the expression of maternal behavior, but nevertheless influence variation in maternal responsiveness and parental behavior both within and between individuals. A growing number of correlational and experimental studies have indicated that high circulating estrogen concentrations during pregnancy increase maternal motivation and responsiveness to infant stimuli, while effects of prepartum or postpartum estrogens and progestogens on maternal behavior are less clear. Prolactin is thought to play a role in promoting paternal and alloparental care in primates, but little is known about the relationship between this hormone and maternal behavior. High circulating cortisol levels appear to enhance arousal and responsiveness to infant stimuli in young, relatively inexperienced female primates, but interfere with the expression of maternal behavior in older and more experienced mothers. Among neuropeptides and neurotransmitters, preliminary evidence indicates that oxytocin and endogenous opioids affect maternal attachment to infants, including maintenance of contact, grooming, and responses to separation. Brain serotonin affects anxiety and impulsivity, which in turn may affect maternal behaviors such as infant retrieval or rejection of infants' attempts to make contact with the mother. Although our understanding of the neuroendocrine correlates of primate maternal behavior has grown substantially in the last two decades, very little is known about the mechanisms underlying these effects, e.g., the extent to which these mechanisms may involve changes in perception, emotion, or cognition.
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Affiliation(s)
- Wendy Saltzman
- Department of Biology, University of California, Riverside, CA 92521, USA.
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17
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Ziegler TE, Prudom SL, Zahed SR. Variations in male parenting behavior and physiology in the common marmoset. Am J Hum Biol 2009; 21:739-44. [PMID: 19367571 PMCID: PMC5030771 DOI: 10.1002/ajhb.20920] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Infant survival and wellbeing is dependent upon good parenting skills. In some species of primates, fathers are necessary to ensure both positive developmental and social outcomes for their offspring. Common marmosets and the related cotton-top tamarin monkeys provide extensive paternal care of multiple offspring and are essential for infant survival. However, we have found significant variation in a father's motivation to respond to infant stimuli. Additionally, marmoset males who are experienced fathers are significantly more motivated to respond to infants and infant stimuli than adult males who have yet to be fathers. Expectant fathers appear to be preparing for their energetic role in infant care by responding with increases in multiple reproductive hormones and showing weight gain during their mate's pregnancy. Male marmosets have been shown to be hormonally responsive to scent signals. Males show increased testosterone shortly after smelling periovulatory scents and lower levels of testosterone following presentation of their own infant's scent. These two inverse testosterone responses combined indicate that paternal males have a flexible system of responding to socially relevant odor cues. Thus males can be ready to mate when their mate is fertile while continuing to be responsive to their infants when these two events occur simultaneously. A male's hormonal and physical responsiveness to parenting may be due to pair bonding between the male and his mate. Examining the variability between males in their behavioral, physical, and hormonal responses to their mate's pregnancy, and infant stimuli provides the means for determining the mechanisms of good parenting in fathers.
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Affiliation(s)
- Toni E Ziegler
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, Wisconsin 53715, USA.
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18
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Ziegler TE, Prudom SL, Zahed SR, Parlow AF, Wegner F. Prolactin's mediative role in male parenting in parentally experienced marmosets (Callithrix jacchus). Horm Behav 2009; 56:436-43. [PMID: 19664636 PMCID: PMC2761515 DOI: 10.1016/j.yhbeh.2009.07.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 07/24/2009] [Accepted: 07/29/2009] [Indexed: 11/19/2022]
Abstract
Prolactin has been implicated in promoting paternal care behaviors but little evidence of causality has been found to date except for birds and fish. This study was designed to examine the possible causal relationships between prolactin and male parenting behaviors, reproductive hormones, and physical changes in cooperatively breeding common marmosets, Callithrix jacchus. Fifteen parentally experienced fathers were studied over three consecutive infant care periods during two weeks prior and three weeks following their mates' parturition under three-treatment conditions: normal control pregnancy, decreased prolactin and elevated prolactin. The treatments significantly altered the serum prolactin levels in the fathers. Using three methods of determining a father's level of parental care: infant carrying, family effort and responsiveness to infant stimulus tests, we found that only the male response to infant stimuli was altered by the hormone treatments. Lowering prolactin significantly reduced male responsiveness to infant stimuli but elevating prolactin showed the same effect. Hormonal sampling indicated that testosterone levels showed an inverse relationship to prolactin levels during a normal peripartum period and prolactin treatment reduced this relationship. Prepartum estradiol levels were significantly elevated during the lowered prolactin treatment and estradiol was significantly lowered postpartum with the elevated prolactin treatment. Father's weight decreased significantly by the third week of infant care during the normal treatment. Males in the elevated prolactin treatment lost little or no weight from prepartum while in the lowered prolactin treatment showed the most weight loss. The present findings did not distinguish a direct causal relationship of prolactin on behavior in experienced fathers but did find an interaction with other hormones and weight gain.
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Affiliation(s)
- Toni E Ziegler
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715, USA.
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19
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Maestripieri D, Hoffman CL, Anderson GM, Carter CS, Higley JD. Mother-infant interactions in free-ranging rhesus macaques: relationships between physiological and behavioral variables. Physiol Behav 2009; 96:613-9. [PMID: 19150451 PMCID: PMC3955190 DOI: 10.1016/j.physbeh.2008.12.016] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 12/11/2008] [Accepted: 12/18/2008] [Indexed: 11/29/2022]
Abstract
Studies of mother-infant relationships in nonhuman primates have increasingly attempted to understand the neuroendocrine bases of interindividual variation in mothering styles and the mechanisms through which early exposure to variable mothering styles affects infant behavioral development. In this study of free-ranging rhesus macaques on Cayo Santiago, Puerto Rico, we aimed to: 1) compare lactating and nonlactating females to investigate whether lactation is associated with changes in plasma cortisol, prolactin and oxytocin, as well as changes in CSF levels of serotonin and dopamine metabolites (5-HIAA and HVA); 2) examine the extent to which interindividual variation in maternal physiology is associated with variation in maternal behavior; 3) examine the extent to which interindividual variation in infant physiology and behavior is accounted for by variation in maternal physiology and behavior. Lactating females had higher plasma concentrations of cortisol, prolactin, and oxytocin but lower CSF concentrations of HVA than nonlactating females. Variation in maternal rejection behavior was positively correlated with variation in maternal plasma cortisol levels and in CSF 5-HIAA levels while variation in the time spent nursing and grooming was associated with maternal plasma oxytocin levels. Infants who were protected more by their mothers had higher cortisol levels than those who were protected less, while infants who were rejected more had lower CSF 5-HIAA than infants who were rejected less. Since exposure to high levels of maternal protectiveness and rejection is known to affect the offspring's behavior and responsiveness to the environment later in life, our results are consistent with the hypothesis that these effects are mediated by long-term changes in the activity of the offspring's HPA axis and brain serotonergic system.
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Affiliation(s)
- Dario Maestripieri
- Department of Comparative Human Development, University of Chicago, 5730 S.Woodlawn Avenue, Chicago, IL 60637 USA.
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20
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Almond REA, Ziegler TE, Snowdon CT. Changes in prolactin and glucocorticoid levels in cotton-top tamarin fathers during their mate's pregnancy: the effect of infants and paternal experience. Am J Primatol 2008; 70:560-5. [PMID: 18278807 DOI: 10.1002/ajp.20529] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We have previously shown that paternally experienced cotton-top tamarin fathers (Saguinus oedipus) had significant increases in prolactin and glucocorticoids at the midpoint of their mate's pregnancy, whereas less experienced fathers showed prolactin increases only the month before offspring birth [Ziegler & Snowdon, Hormones & Behavior 38:159-167, 2000; Ziegler et al., Hormones & Behavior 45:84-92, 2004]. These results could be owing to differing paternal experience or from paternal care given to previous offspring. To test the relative role of infant cues and paternal experience in these hormonal changes, we paired four paternally experienced tamarin fathers with a novel, primiparous female and monitored hormone levels during their first pregnancy together. No fathers showed the significant mid-pregnancy increase in prolactin seen previously. However, all fathers showed increases in cortisol and significant peaks of corticosterone in mid-pregnancy. The increase in corticosterone was consistent with previous data occurring in each male during the same week or the week following the urinary cortisol increase shown by his mate. These data may suggest that the elevated mid-gestation prolactin seen previously in experienced males may be owing to the presence of offspring from the previous set of infants. In contrast, increased cortisol and corticosterone occurred independently of infant cues and may be related to previous paternal experience. We therefore conclude that both offspring presence and paternal experience contribute to the hormonal changes seen in experienced cotton-top tamarin fathers during their mate's pregnancy.
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Affiliation(s)
- Rosamunde E A Almond
- Department of Psychology, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, Wisconsin 53713, USA
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21
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Schradin C. Differences in prolactin levels between three alternative male reproductive tactics in striped mice (Rhabdomys pumilio). Proc Biol Sci 2008; 275:1047-52. [PMID: 18230588 DOI: 10.1098/rspb.2008.0004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In male fishes, birds and mammals, increased prolactin secretion is thought to play a role in species showing paternal behaviours. This hypothesis was investigated in the striped mouse (Rhabdomys pumilio). This paper compares serum prolactin levels in 71 free-living male striped mice following three different reproductive tactics: (i) paternal group-living breeders, (ii) alloparental philopatric group-living males, and (iii) roaming non-paternal solitary males. Prolactin levels of breeding males were significantly higher than that of roamers. Alloparental philopatric males had low prolactin levels, which concur with studies of cooperatively breeding mammals, but contrasts with studies of cooperatively breeding birds. Both breeding males and females showed a decrease in prolactin levels after the breeding season, but not alloparental philopatric males. Prolactin levels were correlated with neither corticosterone levels nor age. These results are in agreement with the hypothesis that prolactin is one proximate mechanism of male reproductive tactics, possibly regulating differences in male parental care.
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Affiliation(s)
- Carsten Schradin
- Department of Animal Behavior, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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22
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Newman JD. Neural circuits underlying crying and cry responding in mammals. Behav Brain Res 2007; 182:155-65. [PMID: 17363076 PMCID: PMC1995563 DOI: 10.1016/j.bbr.2007.02.011] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 02/07/2007] [Accepted: 02/10/2007] [Indexed: 12/26/2022]
Abstract
Crying is a universal vocalization in human infants, as well as in the infants of other mammals. Little is known about the neural structures underlying cry production, or the circuitry that mediates a caregiver's response to cry sounds. In this review, the specific structures known or suspected to be involved in this circuit are identified, along with neurochemical systems and hormones for which evidence suggests a role in responding to infants and infant cries. In addition, evidence that crying elicits parental responses in different mammals is presented. An argument is made for including 'crying' as a functional category in the vocal repertoire of all mammalian infants (and the adults of some species). The prevailing neural model for crying production considers forebrain structures to be dispensable. However, evidence for the anterior cingulate gyrus in cry production, and this structure along with the amygdala and some other forebrain areas in responding to cries is presented.
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Affiliation(s)
- John D Newman
- Laboratory of Comparative Ethology, National Institute of Child Health and Human Development, NIH, DHHS, Box 529, Poolesville, MD 20837, USA.
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23
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Wynne-Edwards KE, Timonin ME. Paternal care in rodents: weakening support for hormonal regulation of the transition to behavioral fatherhood in rodent animal models of biparental care. Horm Behav 2007; 52:114-21. [PMID: 17482188 DOI: 10.1016/j.yhbeh.2007.03.018] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 03/27/2007] [Accepted: 03/28/2007] [Indexed: 11/26/2022]
Abstract
Male rodents that are naturally paternal, like all females, must inhibit infanticide and activate direct parental behavior as they become parents. Males, however, alter their behavior in the absence of parturition, postpartum ovulation and lactation, and therefore do not experience the hormone dynamics associated with such conditions. Paternal males might nevertheless use the same hormones to activate pre-existing maternal behavior pathways in the brain. Positive and inverse associations between prolactin, sex steroids (estradiol, testosterone, progesterone), glucocorticoids, oxytocin and vasopressin and paternal behavior are reviewed. Across biparental rodents (Phodopus campbelli, Peromyscus californicus, Microtus ochrogaster, and Meriones unguiculatus), as well as non-human primates and men, hormone-behavior associations are broadly supported. However, experimental manipulations (largely restricted to P. campbelli) suggest that the co-variation of hormones and paternal behavior is not causal in paternal behavior. Perhaps the hormone-behavior associations shared by P. campbelli and other paternal males are important for other challenges at the same time as fatherhood (e.g., mating during the postpartum estrus). On the other hand, each paternal species might, instead, have unique neuroendocrine pathways to parental behavior. In the latter case, future comparisons might reveal extraordinary plasticity in how the brain forms social bonds and alters behavior in family groups.
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24
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Delahunty KM, McKay DW, Noseworthy DE, Storey AE. Prolactin responses to infant cues in men and women: effects of parental experience and recent infant contact. Horm Behav 2007; 51:213-20. [PMID: 17150219 DOI: 10.1016/j.yhbeh.2006.10.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 10/16/2006] [Accepted: 10/16/2006] [Indexed: 11/23/2022]
Abstract
We used a longitudinal design to test whether parental experience differentially affects the development of prolactin responses to infant cues in men and women. Couples provided two blood samples at three tests, one test just before their babies were born, and two tests during the early postnatal period (n=21). Nine couples repeated the tests near the birth of their second babies. In the 30 min between the two samples, couples listened to recorded infant cries at the prenatal test and held their baby (fathers) or a doll (mothers) at the postnatal tests. Blood samples were analyzed for prolactin concentrations. Prolactin values were then related to sex and parity differences as well as to questionnaire data concerning emotional responses to infant cries and previous infant contact. We found that (1) prior to the birth of both the first and second babies, women's prolactin concentrations increased after exposure to infant stimuli, whereas men's prolactin concentrations decreased; postnatal sex differences varied with parity; (2) women's prolactin reactivity did not change significantly with parental experience; (3) the same men's prolactin concentrations decreased after holding their first newborns but increased after holding their second newborns; this change was not gradual or permanent; (4) men reporting concern after hearing recorded infant cries showed a different postnatal pattern of prolactin change after holding their babies than men not reporting concern; and (5) men who had little contact with their babies just prior to testing had a more positive prolactin response than men who had recently held their babies for longer periods. Although parental experience appears to affect men's prolactin responses, differences in reactivity were also related to patterns of recent infant contact and individual differences in responses to infant cues.
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Affiliation(s)
- Krista M Delahunty
- Cognitive and Behavioural Ecology Graduate Programme, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
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25
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Carlson AA, Russell AF, Young AJ, Jordan NR, McNeilly AS, Parlow AF, Clutton-Brock T. Elevated prolactin levels immediately precede decisions to babysit by male meerkat helpers. Horm Behav 2006; 50:94-100. [PMID: 16527276 DOI: 10.1016/j.yhbeh.2006.01.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 01/27/2006] [Accepted: 01/30/2006] [Indexed: 11/15/2022]
Abstract
Recent studies suggest that decisions to care for the offspring of others in societies of cooperative vertebrates may have a hormonal basis. The crucial question of whether changes in hormone levels immediately precede or merely follow bouts of offspring care, however, remains largely unanswered. Here, we show that in wild groups of cooperatively breeding meerkats, male helpers that decided to babysit for the day had significantly higher levels of prolactin, coupled with lower levels of cortisol, before initiating a babysitting session compared with similarly aged individuals that decided to forage. In addition, these hormonal differences disappeared over the course of the day, suggesting that hormone levels changed in a fundamentally different way in meerkats that babysat versus those that foraged. In contrast, long-term contributions to babysitting were not significantly associated with plasma levels of prolactin, cortisol, or testosterone in individual male helpers. Our results show, for the first time, that elevated levels of prolactin may immediately precede bouts of helping behavior but differ from recent findings on the same study population in which plasma levels of cortisol, but not prolactin, were significantly and positively associated with rates of pup feeding by male helpers. Together, these results lend significant weight to the idea that decisions to help in cooperative vertebrates have a hormonal basis, although different hormones appear to be associated with different types of care.
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Affiliation(s)
- Anne A Carlson
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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26
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Almond REA, Brown GR, Keverne EB. Suppression of prolactin does not reduce infant care by parentally experienced male common marmosets (Callithrix jacchus). Horm Behav 2006; 49:673-80. [PMID: 16480723 DOI: 10.1016/j.yhbeh.2005.12.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 12/06/2005] [Accepted: 12/08/2005] [Indexed: 01/23/2023]
Abstract
High levels of prolactin have been found to correlate with the expression of paternal care in a variety of taxa. However, in mammals, there is little experimental evidence that prolactin is causally involved in the stimulation or maintenance of paternal care. Here, we suppressed prolactin production in paternally experienced common marmoset fathers in their family groups during the first 2 weeks after their infants were born. Circulating prolactin levels were suppressed using cabergoline (Dostinex: Pfizer), a long acting dopamine (D2) agonist with minimal behavioural side-effects. A within-subject design was used to compare behavioural and hormonal data on 5 paternally experienced fathers during two consecutive births. Cabergoline reduced prolactin to negligible levels in all fathers without effecting testosterone, DHT and cortisol and without adverse side-effects. However, lowering prolactin had no significant effect on the expression of majority of the behaviour patterns associated with paternal care. These included infant carrying, infant grooming and the frequency with which fathers retrieved and rejected infants. The only infant-related behaviour to be affected was the frequency with which fathers touched, licked and investigated infants. We noted a marginally significant increase in this behaviour during cabergoline treatment. Despite the lack of effect on paternal care, cabergoline did exert an effect on the affiliative/sexual behaviour of fathers as there was a significant increase in the grooming behaviour fathers directed at and received from their mates during drug treatment. This study showed that experienced male marmosets can express paternal behaviour in the absence of the high prolactin levels normally seen after infants are born.
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Affiliation(s)
- Rosamunde E A Almond
- Department of Psychology, University of Wisconsin, 1202 West Johnson Street, Madison, WI 53706, USA.
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27
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Saltzman W, Ahmed S, Fahimi A, Wittwer DJ, Wegner FH. Social suppression of female reproductive maturation and infanticidal behavior in cooperatively breeding Mongolian gerbils. Horm Behav 2006; 49:527-37. [PMID: 16378607 DOI: 10.1016/j.yhbeh.2005.11.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 11/08/2005] [Accepted: 11/16/2005] [Indexed: 11/26/2022]
Abstract
In several cooperatively breeding species, reproductively suppressed, nonbreeding females are attracted to infants and routinely provide alloparental care, while breeding females may attack or kill other females' infants. The mechanisms underlying the transition from alloparental to infanticidal behavior are unknown. In this study, we tested the hypothesis that this transition is associated with cessation of reproductive suppression and onset of ovarian activity in the Mongolian gerbil (Meriones unguiculatus), a cooperatively breeding rodent. Young female gerbils were housed with their natal family (FH), with a female pairmate (PH) or singly (SH). When females were either 11-13 or 16-18 weeks of age, we characterized their behavioral responses to an unfamiliar pup, reproductive development, and plasma progesterone, cortisol, and prolactin concentrations. In both age groups, FH females were significantly less likely to attack pups than PH or SH females and in fact never did so. FH females also had smaller ovaries and uteri, less developed scent glands, and lower progesterone levels, and were more likely to be anovulatory than PH or SH females, especially in the 11- to 13-week-old age group. Prolactin concentrations did not differ with reproductive status but were significantly higher in females that did not attack pups than in those that did. We found no other significant associations, however, between reproductive or endocrine measures and behavioral responses to pups. These results suggest that cohabitation with the natal family inhibits both infanticidal behavior and reproductive maturation in young female gerbils but that these two effects may not be causally related.
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Affiliation(s)
- Wendy Saltzman
- Department of Biology, University of California, Riverside, 92521, USA.
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28
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Smale L, Heideman PD, French JA. Behavioral neuroendocrinology in nontraditional species of mammals: things the 'knockout' mouse CAN'T tell us. Horm Behav 2005; 48:474-83. [PMID: 15990097 PMCID: PMC2981860 DOI: 10.1016/j.yhbeh.2005.05.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 05/01/2005] [Accepted: 05/03/2005] [Indexed: 11/25/2022]
Abstract
The exploration of many of the fundamental features of mammalian behavioral neuroendocrinology has benefited greatly throughout the short history of the discipline from the study of highly inbred, genetically characterized rodents and several other "traditional" exemplars. More recently, the impact of genomic variation in the determination of complex neuroendocrine and behavioral systems has advanced through the use of single and multiple gene knockouts or knockins. In our essay, we argue that the study of nontraditional mammals is an essential approach that complements these methodologies by taking advantage of allelic variation produced by natural selection. Current and future research will continue to exploit these systems to great advantage and will bring new techniques developed in more traditional laboratory animals to bear on problems that can only be addressed with nontraditional species. We highlight our points by discussing advances in our understanding of neuroendocrine and behavioral systems in phenomena of widely differing time scales. These examples include neuroendocrine variation in the regulation of reproduction across seasons in Peromyscus, variation in parental care by biparental male rodents and primates within a single infant rearing attempt, and circadian variation in the regulation of the substrates underlying mating in diurnal vs. nocturnal rodents. Our essay reveals both important divergences in neuroendocrine systems in our nontraditional model species, and important commonalities in these systems.
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Affiliation(s)
- Laura Smale
- Departments of Zoology, Michigan State University, East Lansing, MI 48843, USA.
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29
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Young AJ, Carlson AA, Clutton-Brock T. Trade-offs between extraterritorial prospecting and helping in a cooperative mammal. Anim Behav 2005. [DOI: 10.1016/j.anbehav.2005.01.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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30
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Saltzman W, Abbott DH. Diminished maternal responsiveness during pregnancy in multiparous female common marmosets. Horm Behav 2005; 47:151-63. [PMID: 15664018 DOI: 10.1016/j.yhbeh.2004.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Revised: 08/13/2004] [Accepted: 10/13/2004] [Indexed: 10/26/2022]
Abstract
Common marmoset monkeys (Callithrix jacchus) live in small groups in which, usually, only a single female breeds and all group members provide infant care. When two females breed concurrently, however, they may commonly kill one another's infants, especially during the peripartum period. To investigate the mechanisms underlying infanticide by breeding females, we characterized responses of multiparous females to infants and determined circulating hormone levels in adult females during early pregnancy, late pregnancy, and the early postpartum period. Additionally, we compared the responses of postpartum females to their own infants and infants of other females (unfamiliar infants). Postpartum females were highly maternal toward both their own and unfamiliar infants, and showed no differences in their behavioral or hormonal responses to the two. During both early and late pregnancy, however, these females exhibited longer latencies to initially approach unfamiliar infants and spent less time carrying unfamiliar infants. Moreover, females spent less time carrying unfamiliar infants during late pregnancy than early pregnancy. Most late pregnant females never carried infants, and those that did rejected them quickly. Prolactin concentrations were higher and progesterone concentrations lower postpartum than in early or late pregnancy, while estradiol concentrations, the estradiol-to-progesterone ratio, and cortisol levels were higher during late pregnancy. Within reproductive conditions, however, maternal behaviors were not correlated with hormone levels. These results suggest that maternal responsiveness in marmosets may be attenuated during pregnancy, especially late pregnancy, and this may contribute to infanticide by breeding females.
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Affiliation(s)
- Wendy Saltzman
- Department of Biology, University of California, Riverside, CA 92521, USA.
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Schradin C, Anzenberger G. Development of prolactin levels in marmoset males: from adult son to first-time father. Horm Behav 2004; 46:670-7. [PMID: 15555510 DOI: 10.1016/j.yhbeh.2004.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2002] [Revised: 04/13/2004] [Accepted: 04/14/2004] [Indexed: 11/24/2022]
Abstract
Previous studies have found a clear relationship between prolactin (prl) and paternal care in various vertebrate taxa. In New World monkeys, it has been demonstrated in several species that fathers have high prolactin levels even during periods without infant rearing. In this study, we followed the reproductive careers of common marmoset males as they transitioned from being an adult son within their native family to fathering their own offspring for the first time. Specifically, we examined the first experience of elevated prolactin levels in marmoset males. Additionally, we investigated the effects of the total number of experienced births as well as of age on prolactin levels. Our results show that common marmoset males did not experience an increase in prolactin secretion after pairing or shortly before birth of their first infants. However, prolactin levels rose more than twofold after the birth of their first infants and had lowered again 2.5 months after this event. We found no correlation between prolactin levels and the number of previous births experienced or age. Our study demonstrates that further work about a possible enhancing effect of prolactin on paternal care, by means of experimentally reducing hormonal levels, should be conducted in common marmosets using first-time fathers before males experience the first paternal increase in prolactin levels.
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Affiliation(s)
- Carsten Schradin
- Anthropologisches Institut und Museum, CH-8057 Zürich, Switzerland
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Mills DA, Windle CP, Baker HF, Ridley RM. Analysis of infant carrying in large, well-established family groups of captive marmosets (Callithrix jacchus). Primates 2004; 45:259-65. [PMID: 15248087 DOI: 10.1007/s10329-004-0095-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2003] [Accepted: 04/22/2004] [Indexed: 11/26/2022]
Abstract
To assess the pattern of infant carrying across time and family members, we counted which animals in 13 well-established family groups of captive-bred marmosets (Callithrix jacchus) carried neonates during the first 8 weeks of life. The neonates were carried almost continuously for the first 3 weeks and then spent progressively more time independently. The mother did most of the carrying for the first 2 weeks, her contribution rising from day 1 to day 3 and declining thereafter. The contribution of the father was high on day 1, declined during the first week, and then rose to a peak in the fourth week. The contribution of the siblings rose sharply during the first week and declined thereafter. There was no overall difference in amount of infant carrying by each parent. The contribution of each sibling was small although in these large families the total contribution by siblings was large. These data may differ from previous observations because the breeding pairs were very well established, the families were large, and all except the youngest animals were very experienced in rearing and carrying. These data emphasise the group-dynamic nature of infant carrying in a primate species.
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Affiliation(s)
- Debbie A Mills
- Department of Experimental Psychology, University of Cambridge, Cambridge, UK
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Schradin C, Pillay N. Prolactin levels in paternal striped mouse (Rhabdomys pumilio) fathers. Physiol Behav 2004; 81:43-50. [PMID: 15059683 DOI: 10.1016/j.physbeh.2003.12.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2003] [Revised: 11/26/2003] [Accepted: 12/18/2003] [Indexed: 11/17/2022]
Abstract
Paternal behavior is associated with an increase in prolactin levels in fish, birds and mammals, including rodents. The striped mouse (Rhabdomys pumilio) from southern Africa shows highly developed paternal care. We investigated whether striped mouse fathers have higher prolactin levels than nonfathers, and whether there is a relationship between tactile stimulation with pups and prolactin secretion in fathers. We measured serum prolactin in 42 male striped mice assigned to one of four different experimental groups (single males, paired males, fathers housed with mother and pups, and fathers separated from their family by a wire-mesh partition). Our results revealed no increases in prolactin levels in fathers, and fathers with tactile contact with pups did not have higher prolactin levels than the fathers that were prevented from making tactile contact with pups. In contrast, experienced males had higher prolactin levels than inexperienced males. Male striped mice are polygynous in nature, living in groups, with three breeding females, and are permanently associated with pups during the breeding season. In a field study, males had higher prolactin levels during the breeding season than during the nonbreeding season. Thus, prolactin secretion in the polygynous striped mouse might be regulated by environmental stimuli, whereas social stimuli might be important for monogamous species. This is the first study to demonstrate seasonal changes in prolactin levels in a free-living male mammal.
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Affiliation(s)
- Carsten Schradin
- Ecophysiological Studies Research Group, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.
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Roberts RL, Jenkins KT, Lawler T, Wegner FH, Newman JD. Bromocriptine administration lowers serum prolactin and disrupts parental responsiveness in common marmosets (Callithrix j. jacchus). Horm Behav 2001; 39:106-12. [PMID: 11243738 DOI: 10.1006/hbeh.2000.1639] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The influence of prolactin on parental responsiveness was investigated in eight unpaired, parentally inexperienced common marmosets (Callithrix jacchus; 6 female, 2 male). The marmosets were prescreened with infants (1-10 days of age) and required to exhibit short latency retrieval and infant carrying in at least three consecutive pretests as criterion for inclusion in this study. The marmosets were then administered the dopamine agonist bromocriptine (0.5 mg/0.5ml vehicle subcutaneously) and the vehicle alone (0.5 ml 10% ethanol solution) twice daily for 3 consecutive days in random order. Bromocriptine treatment reduced circulating prolactin to nondetectable levels. Bromocriptine treatment eliminated infant retrieval in four of the eight marmosets and was associated with significantly increased retrieval latencies and significantly reduced carrying durations in the four monkeys that continued to retrieve following bromocriptine treatment. When given the vehicle alone, the marmosets retrieved infants significantly faster than during pretests, suggesting a handling effect of the injection series. Bromocriptine treatments were associated with significantly increased movement during the tests. The results of this study indicate that prolactin and/or its regulatory neurotransmitters are involved in the control of the spontaneous display of parental responsiveness in common marmosets.
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Affiliation(s)
- R L Roberts
- Unit on Developmental Neuroethology, University of Wisconsin, Madison, Wisconsin 53715, USA.
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