Meeting Abstract

18.1  Tuesday, Jan. 4  Age and sex effects and long-term repeatability of aerobic capacity in a wild population of satin bowerbirds (Ptilonorhynchus violaceus) CHAPPELL, M.A.*; SAVARD, J.F.; SIANI, J.; COLEMAN, S.W; BORGIA, G.; Univ. of California, Riverside; Univ. of Maryland; Univ. of Maryland; Univ. of Maryland; Univ. of Maryland chappell@ucr.edu

Aerobic capacity limits sustainable activity and hence is important for migration, prey pursuit or predator evasion, intraspecific aggression, and other fitness-critical behaviors. It may also be useful in the context of sexual selection as a highly integrative trait that could provide information on the health, vigor, and perhaps genetic quality of prospective mates. The latter may be particularly valuable in species where the only male contribution to offspring is sperm, such as lekking species or bowerbirds. We used a ‘flight wheel’ to measure aerobic capacity as maximal oxygen consumption (VO_2max) as part of a long-term study of a wild population of satin bowerbirds in northeastern New South Wales, Australia. Individuals in this population are banded and color-marked; sex and age were determined from plumage, banding records, or video recordings at bowers. We hypothesized that VO_2max would be repeatable within and across years, and that adult males, especially bower-holding individuals, would have higher VO_2max than juveniles or females. In 358 bowerbirds, adult males had significantly higher VO_2max than females and juveniles (5-6% difference after compensating for body mass), but there was no difference between successful (bower-holding) males and unsuccessful males. In adults, there was no significant effect of age on VO_2max, although it tended to decline with increasing age. VO_2max was significantly repeatable both within and across years indicating that it can be a reliable index of aerobic performance.