TY - JOUR
T1 - The role of androgens in opportunistic breeding, tropical frogs
AU - Emerson, Sharon B.
AU - Hess, David L.
N1 - Funding Information:
C. Collier, J. Woolf, K. Abduhl, I. Garcia, and L. Carroll provided assistance in field collection of animals. R. Inger, H. Voris, and R. Stuebing also helped at various stages of the work. Discussions with L. Houck, C. Propper, and P. Narins were very educational, and we especially appreciate the comments of L. Houck and C. Propper on an early draft of the manuscript. We thank the Malaysian Government, Danum Valley Field Centre, and the University of Malaya for the opportunity to collect these data. Professor Yong Hoi Sen has been particularly helpful and his hospitality is greatly appreciated. This research was supported by National Science Foundation Grants BSR-8822630 and DEB-9317642 to S.B.E. and by NIH RR 00163 and HD18185 to D.L.H.
PY - 1996/8
Y1 - 1996/8
N2 - In this paper we present the results of an interspecific study on the androgen levels of several species of Old World tropical frogs. These data are used to test three hypotheses: (1) in unpredictable, aseasonal environments with opportunistic breeding, gonadal hormones have a permissive rather than an activating role in the expression of mating behavior (Crews and Moore, 1986), (2) a behaviorally induced androgen response is present in opportunistic aseasonal species as well as in temperate seasonal breeders (Crews and Moore, 1986; Wingfield et al., 1990), and (3) because maintenance of high plasma testosterone levels has an associated energetic and/or fitness cost (Moore and Marler, 1987; Wingfield et al., 1990), continuously breeding frogs have lower testosterone levels than seasonal, discontinuous breeders. Androgen and corticosterone levels were found to vary significantly among species exhibiting the same mating behavior, providing support for the hypothesis that hormones have a permissive role. Differences in androgen level were correlated with (1) variation in level of male-male aggression, (2) relative density of male frogs, and (3) call rate and power output of male vocalization. These results indicate that a behaviorally induced androgen response is present in opportunistic, aseasonal breeders. Furthermore, tropical, aseasonal, opportunistic breeding frogs appeared to have lower androgen levels, generally, than confamilial temperate, seasonal breeders. This difference is consistent with the hypothesis that maintenance of high plasma testosterone levels is energetically expensive.
AB - In this paper we present the results of an interspecific study on the androgen levels of several species of Old World tropical frogs. These data are used to test three hypotheses: (1) in unpredictable, aseasonal environments with opportunistic breeding, gonadal hormones have a permissive rather than an activating role in the expression of mating behavior (Crews and Moore, 1986), (2) a behaviorally induced androgen response is present in opportunistic aseasonal species as well as in temperate seasonal breeders (Crews and Moore, 1986; Wingfield et al., 1990), and (3) because maintenance of high plasma testosterone levels has an associated energetic and/or fitness cost (Moore and Marler, 1987; Wingfield et al., 1990), continuously breeding frogs have lower testosterone levels than seasonal, discontinuous breeders. Androgen and corticosterone levels were found to vary significantly among species exhibiting the same mating behavior, providing support for the hypothesis that hormones have a permissive role. Differences in androgen level were correlated with (1) variation in level of male-male aggression, (2) relative density of male frogs, and (3) call rate and power output of male vocalization. These results indicate that a behaviorally induced androgen response is present in opportunistic, aseasonal breeders. Furthermore, tropical, aseasonal, opportunistic breeding frogs appeared to have lower androgen levels, generally, than confamilial temperate, seasonal breeders. This difference is consistent with the hypothesis that maintenance of high plasma testosterone levels is energetically expensive.
UR - http://www.scopus.com/inward/record.url?scp=0030219827&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030219827&partnerID=8YFLogxK
U2 - 10.1006/gcen.1996.0113
DO - 10.1006/gcen.1996.0113
M3 - Article
C2 - 8812378
AN - SCOPUS:0030219827
SN - 0016-6480
VL - 103
SP - 220
EP - 230
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
IS - 2
ER -