Meeting Abstract

P3.5  Monday, Jan. 6 15:30  Male and female newts increase corticosterone during amplexus REEDY, AM; EDWARDS, A; PENDLEBURY, C; MURDAUGH, L; AVERY, R; SEIDENBERG, J; ASPBURY, AS; GABOR, CR*; Univ. of Virginia; Univ. of Virginia; Univ. of Virginia; Indiana Univ. of Pennsylvania; Univ. of Virginia; Mountain Lake Biological Station; Texas State Univ.; Texas State Univ. gabor@txstate.edu

Hormones play key functional roles in mediating the tradeoff between survival and reproduction that is the result of different biological processes competing for limited resources. Glucocorticoid (GC) hormones play a role in inhibiting reproduction and improving chances of survival during periods of stress. However, a growing body of work shows that GC hormones are at times associated with successfully engaging in energetically costly courtship and mating behaviors. While corticosterone (CORT), a primary GC hormone in amphibians, reptiles and birds, may be important in activating or sustaining energetically costly mating behaviors, sexual conflict over differences in the optimum mating frequency for males and females sets the stage for sex specific responses of the hypothalamic-pituitary-adrenal axis during courtship and mating. Here we show that an acute increase in CORT is associated with amplexus behavior in male and female red-spotted newts (Notophthalmus viridescens). Additionally we demonstrate that males have higher overall CORT release rates both in and out of amplexus than do females. Although costs associated with elevated CORT apply to both sexes, frequent amplexus should confer greater fitness benefits to males relative to females. Our finding of higher CORT in males both in and out of amplexus is consistent with this expectation of greater fitness benefits for males. Our results support the hypothesis that GC hormones can play a key role in energetically costly courtship and mating behaviors.