Meeting Abstract

P1.191  Wednesday, Jan. 4  Self-maintenance versus reproduction: effect of experimentally increased food availability on female incubation behavior, chronic stress levels, and offspring condition in house wrens LOTHERY, C.J.*; THOMPSON, C.F.; SAKALUK, S.K.; Illinois State University; Illinois State University; Illinois State University

Corticosterone (CORT), the “avian stress hormone,” increases in the plasma during times of chronic or acute stress (e.g., low food availability or presence of a predator, respectively), and can mediate a shift toward self-maintenance behaviors that ensure survival (e.g., foraging or nest abandonment). Birds incubating eggs face the potentially stressful problem of how to allocate their time and energy between maintaining the proper temperature of the embryos developing in their eggs and obtaining enough food to meet their own metabolic demands. We tested the hypothesis that female house wrens (Troglodytes aedon), which incubate their eggs without male help, face a trade-off during the incubation period between self-maintenance behaviors (leaving the nest to forage for food) and warming their eggs, and that this trade-off results in increased levels of chronic stress during incubation. We predicted that food-supplemented females would (i) incubate their eggs for longer periods, (ii) experience less stress, and (iii) produce offspring in better condition than control females. The results are consistent with the hypothesis as food-supplemented females spent more time incubating their eggs than control females. Results of the analyses of plasma CORT levels and measures of offspring condition will also be reported.