Meeting Abstract

78.1  Monday, Jan. 6 10:15  Impacts of avian malaria and related parasites on lifetime reproductive success and survivorship of mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) ZYLBERBERG, M*; DERRYBERRY, EP; BREUNER, CW; MACDOUGALL-SHACKLETON, EA; CORNELIUS, JM; HAHN, TP; Univ. of California, Davis; Tulane University; University of Montana; University of Western Ontario; Univ. of California, Davis; Univ. of California, Davis xylberg@gmail.com

Interactions between haematozoan parasites and their avian hosts are frequently used to model fundamental questions in ecology and evolution. However, the basic assumption that these parasites consistently reduce host fitness in the wild has yet to be conclusively addressed. To this end, we conducted a long-term study examining the relationship between naturally-occurring infection with Haemoproteus and Plasmodium, and lifetime reproductive success and survival of mountain white-crowned sparrows (Zonotrichia leucophrys oriantha). Specifically, we tested the hypothesis that birds infected with haematozoan parasites should have reduced survival and reproductive success (as determined by overwinter return rates and eggs laid, hatched, and nestlings fledged, respectively). We found no difference in lifetime reproductive success and survival of Plasmodium infected and uninfected individuals, or in Haemoproteus infected and uninfected males. Contrary to expectation, we found that Haemoproteus-infected females exhibited a trend towards increased annual reproductive success and had significantly higher overwinter return rates, with the result that these females fledged more than twice as many chicks during their lifetimes as did uninfected females. We discuss the impact of parasitic infections on host fitness in light of these findings and suggest that, in the case of less virulent pathogens, investment in excessive immune defense may decrease lifetime reproduction.