Meeting Abstract

P3.7  Wednesday, Jan. 6  Costs and benefits of a sexually selected ornament in male threadfin rainbowfish, Iriatherina werneri. CONDON, CH*; TRAPPETT, AG; WHITE, CR; WILSON, RS; The University of Queensland, Australia; The University of Queensland, Australia; The University of Queensland, Australia; The University of Queensland, Australia c.condon@uq.edu.au

Sexually selected traits are used as inter-specific signals of reproductive potential and mate quality. Theory predicts that females choose males that display elaborate sexually selected traits as they are considered to be reliable indicators of male quality. The exaggeration of male ornamentation is thought to be constrained by the costs of producing and maintaining these traits. Here we investigate the costs and benefits of an exaggerated sexually selected ornament in the male threadfin rainbowfish, Iriatherina werneri. Male I. werneri possess long thread-like extensions from the second dorsal and anal fins and a large fan-shaped first dorsal fin that are used in both courtship and male competition. To examine the benefit of ornamentation to males, we conducted male choice trials to determine whether males with larger ornaments were also more attractive to females. We also examined the costs of fin ornamentation by investigating both the metabolic cost of activity and maximum escape velocity for males with different size ornaments. We found that males with larger ornamentation received the most attention from females however larger fins were also costly, resulting in an increase in resting metabolic rate.