Meeting Abstract
Historically, elevated stress hormones are thought to suppress reproductive effort, as summarized in the ‘cort-fitness hypothesis’ and the ‘cort-trade-off hypothesis.’ However, that elevated glucocorticoids (GCs) during breeding can predict greater reproductive success. This increase in GCs might be associated with the increased metabolic demands of parental care and has been termed the ‘cort-adaptation hypothesis.’ Combining these three hypotheses describes two contrasting relationships between GCs and reproductive behavior. In order to more clearly understand how GCs predict parental behavior we observed several aspects of parental effort including feeding rates, nest attendance, defensive behavior and nestling growth rates in tree swallows (Tachycineta bicolor). We also evaluated both baseline and stress-induced GC levels during the mid-nestling phase. I will present on the relationship between plasma GCs and parental effort in order to help understand the discrepancies in understanding of GCs, stress, and parental investment.
