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Lind CM, Ramis F, Paredes DJG, Moore IT, Vernasco BJ, Farrell TM. Mechanisms underlying maternal care in a viviparous snake, Sistrurus miliarius: Does maternal body condition, corticosterone, or arginine vasotocin mediate post-birth maternal investment? JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 327:458-465. [PMID: 29356456 DOI: 10.1002/jez.2132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 11/06/2022]
Abstract
The level of parental investment in free-living offspring varies greatly within and among vertebrate taxa, and the mechanisms that mediate investment are likely targets of selection in the evolution of reproductive strategies. In mammalian and avian systems, individual investment is adjusted according to parental energetic status, and regulatory mechanisms have been described. Parental care is also a component of the life history of several groups of squamates and archosaurs, but little to nothing is known regarding the mechanisms that underlie individual variation in parental investment in these groups. Therefore, we examined the relationships among maternal body condition, corticosterone, arginine vasotocin (AVT), and maternal care in postparturient pigmy rattlesnakes. Energetic status was manipulated in pregnant females by supplemental feeding, and AVT was manipulated in postparturient mothers by intraperitoneal injection. Circulating corticosterone and body condition were recorded in postparturient mothers. Mother-offspring spatial relationships were analyzed to determine the closeness of mother-offspring associations. No significant relationship between maternal body condition and baseline corticosterone was observed in mothers, and no significant relationship was found between corticosterone and the level of maternal association with offspring. Manipulation of AVT did not stimulate maternal care. There was a strong and repeatable positive relationship between maternal postparturient body condition and the level of maternal association with offspring. The lack of a significant correlation between body condition and corticosterone does not support the hypothesis that a postparturient glucocorticoid response drives the observed condition-dependence of maternal offspring association.
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Affiliation(s)
- Craig M Lind
- Department of Biology, Stetson University, Deland, Florida, USA.,Department of Natural Sciences and Mathematics, Stockton University, Galloway, New Jersey, USA
| | - Fatima Ramis
- Department of Biology, Stetson University, Deland, Florida, USA
| | | | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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Lind CM, Birky NK, Porth AM, Farrell TM. Vasotocin receptor blockade disrupts maternal care of offspring in a viviparous snake, Sistrurus miliarius. Biol Open 2017; 6:283-289. [PMID: 28069591 PMCID: PMC5312107 DOI: 10.1242/bio.022616] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Parental care is a complex social behavior that is widespread among vertebrates. The neuroendocrine regulation of parent-offspring social behavior has been well-described in mammals, and to a lesser extent, in birds and fish. However, little is known regarding the underlying mechanisms that mediate the expression of care behaviors in squamate reptiles. In mammalian model species and humans, posterior pituitary hormones of the oxytocin and vasopressin families mediate parental care behaviors. To test the hypothesis that the regulatory role of posterior pituitary neuropeptides is conserved in a viviparous squamate reptile, we pharmacologically blocked the vasotocin receptor in post-parturient pigmy rattlesnakes, Sistrurus miliarius, and monitored the spatial relationship between mothers and offspring relative to controls. Mothers in the control group demonstrated spatial aggregation with offspring, with mothers having greater post-parturient energy stores aggregating more closely with their offspring. Blockade of vasotocin receptors eliminated evidence of spatial aggregation between mothers and offspring and eliminated the relationship between maternal energetic status and spatial aggregation. Our results are the first to implicate posterior pituitary neuropeptides in the regulation of maternal behavior in a squamate reptile and are consistent with the hypothesis that the neuroendocrine mechanisms underlying social behaviors are broadly conserved among vertebrates.
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Affiliation(s)
- Craig M Lind
- Department of Biology, Stetson University, Deland, FL 32723, USA
| | | | - Anita M Porth
- Department of Biology, Stetson University, Deland, FL 32723, USA
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Krohmer R, Lutterschmidt D. Environmental and Neuroendorcrine Control of Reproduction in Snakes. REPRODUCTIVE BIOLOGY AND PHYLOGENY OF SNAKES 2011. [DOI: 10.1201/b10879-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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