Meeting Abstract

P3.3  Monday, Jan. 6 15:30  Immune investment, muscles, and female mate choice MANESS, TJ*; ANDERSON, DJ; Louisiana Tech Univerity; Wake Forest University tmaness@latech.edu

Mate choice hypotheses are based on the premise that choosers exploit phenotypic cues that accurately predict the potential mate’s fitness. Behavioral ecologists traditionally link “individual quality” with exaggerated secondary sexual characteristics or suites of phenotypically variable cues or behaviors. Life history theory suggests that high quality individuals are better able to afford investment in breeding than are low quality individuals, and so should express these relevant cues in a more attractive manner. Populations with biased operational sex ratios provide opportunities to investigate mate choice since the bias offers members of the limiting sex the opportunity to choose among competing potential mates. We investigated mate choice in a male-biased population of Nazca boobies and tested the hypothesis that males selected as mates are in better condition than are males not selected as mates. We weighed and collected serum samples from males two months prior to the egg laying period and performed a clinical health screen of serum enzymes, proteins, and metabolites. We also measured baseline corticosterone (stress hormone), testosterone, and immunoglobulin IgY. Males with low current investment in immune defense and greater muscle mass/exertion were much more likely to be selected as mates than were males with high immune investment and lower muscle mass/exertion.