Meeting Abstract
Being a mother is energetically costly for mammals and is associated with pronounced changes in mothers’ physiology, morphology and behavior. In ~5% of mammals, fathers assist their mates with rearing offspring and can enhance pup survival and development. Although these beneficial consequences of paternal care can be mediated by direct effects on offspring, they might also be mediated indirectly, through beneficial effects on mothers. We tested the hypothesis that fathers in biparental species reduce the burden of parental care in their mates, and therefore that females rearing offspring with and without assistance from their mates will show differences in physiology, morphology and behavior, as well as in survival and development of pups. Using the monogamous, biparental California mouse (Peromyscus californicus), we compared measures relevant to metabolism and emotionality among mothers rearing pups with and without their mates, as well as nonbreeding females. We also monitored development of pups. Half of the animals in each reproductive group were housed under standard laboratory conditions and the other half in cages requiring them to climb wire mesh towers (~8 cm in diameter and ~50 cm in height) to obtain food and water. Preliminary data indicated that single mothers approached a novel object more quickly (P = 0.024) and performed more sniffing and touching of the novel object (P = 0.014), compared to both paired mothers and nonbreeding females. Both single and paired mothers had higher liver mass than nonbreeding females (P = 0.021). Neither reproductive nor housing condition significantly affected litter size, pups’ body mass or age of eye opening. Ongoing analyses are expected to reveal additional effects of mate absence on mothers’ physiological, morphological, and behavioral responses to motherhood.
Supported by NSF IOS 1256572
