Meeting Abstract
53.1 Sunday, Jan. 5 13:30 Breeding under stress: physiological factors influencing nest failure during inclement weather conditions OUYANG, JQ*; LENDVAI, AZ; DAKIN, R; DOMALIK, AD; FASANELLO, VJ; VASSALLO, BG; HAUSSMANN, MF; MOORE, IT; BONIER, F; Virginia Tech; Virginia Tech; Queen’s Univ; Queen’s Univ; Bucknell Univ; Bucknell Univ; Bucknell Univ; Virginia Tech; Queen’s Univ jqouyang@gmail.com
Brood desertion represents a major reproductive decision, especially for short-lived species that have one breeding attempt per year; however, how animals integrate internal and external conditions to mediate this decision remains to be clarified. Endocrine systems, and in particular glucocorticoids (GCs), a group of highly conserved steroid hormones, are emerging as likely candidates for the regulation of reproductive decisions, as they link environmental stimuli and phenotypic expression. While slight elevations of adult GC levels can increase parental effort during the breeding season, large increases in circulating GCs can have the opposite effect by decreasing parental investment (for instance by causing brood desertion). To investigate the effects of GCs on reproductive decisions, we experimentally increased corticosterone levels in free-living adult female tree swallows (Tachycineta bicolor) during the chick-rearing stage using pellet implants. Incidentally, a period of inclement weather caused 92% of the nests in our study population to fail, which allowed us to analyze the factors that predicted brood desertion. Corticosterone treatment of mothers did not affect offspring survival. When analyzed in combination with weather conditions however, high wind speeds, low ambient temperature, and corticosterone treatment were all associated with reduced offspring survival. High parental feeding rates of the female, but not the male, were associated with increased brood survival time. Our results demonstrate the effect of corticosterone on reproductive decisions under extreme environmental conditions.
