SCHRADER, Matthew S; Florida State University, Tallahassee: Parental Effort and Parasite Resistance in the Red-bellied Woodpecker

Traditionally, food limitation and nest predation were thought to be the major ecological forces shaping avian life histories. However, several recent studies have demonstrated a trade-off between reproductive effort and parasite resistance. These studies have led ecologists to reconsider the role of parasites in population dynamics and life-history evolution. Using observational and experimental approaches, I investigated whether there is a trade-off between parental effort and resistance to a haematozoan parasite in a population of Red-bellied Woodpeckers nesting in the Apalachicola National Forest, north Florida. In the observational portion of this study I examined how parasite prevalence varied over a 15-month period, and how infection was associated with host condition and overwinter survival. I also used a brood manipulation experiment to examine whether there is a trade-off between raising additional young and parasite resistance. The proportion of individuals infected with haematozoa varied seasonally, with the highest prevalence of infection coinciding with the Red-bellied Woodpecker breeding season. Infected male Red-bellied Woodpeckers weighed less and were in poorer condition than uninfected males, however there was no association between infection and female mass or body condition. There was also no association between infection with haematozoa and overwinter survival, although uninfected males tended to survive better than infected males. Males caring for enlarged broods were more likely to be parasitized than males caring for control or decreased broods, however there was no effect of brood manipulation on the proportion of females infected. These results suggest that a trade-off between parental effort and parasite resistance may mediate the cost of reproduction in the Red-bellied Woodpecker.