Glucocorticoids predict the honesty of direct benefits associated with a sexually selected trait in the mountain bluebird (Sialia currucoides)


Meeting Abstract

P1-121  Thursday, Jan. 5 15:30 – 17:30  Glucocorticoids predict the honesty of direct benefits associated with a sexually selected trait in the mountain bluebird (Sialia currucoides). BERK, SA*; BREUNER, CW; University of Montana; University of Montana sara.berk@umconnect.umt.edu

Models of the process of sexual selection necessitate a mechanism that maintains honesty, but it is unclear if that honesty is maintained across degrading environmental conditions. We evaluated whether male coloration (a sexually selected trait) and glucocorticoids (CORT) predict the persistence of honesty across early and late season broods in the mountain bluebird, Sialia currucoides. In our study, females mated to more elaborately colored males always had larger broods, but these females were in worse body condition during second broods. In males, higher CORT predicted lower body condition during second broods, when benefits to females were lower. Furthermore, male CORT physiology was negatively associated with female body condition during both first and second broods. This suggests that while females may obtain increased fecundity from mating with more elaborate males, this may come at a cost to themselves when environmental conditions deteriorate.

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