Meeting Abstract
31.6 Jan. 5 Seasonal regulation of adrenocortical response to stress in two species of snowfinches on the Tibet Plateau WANG, Gang*; RICHARDSON, Matthew I.; MOORE, Ignacio T.; SOMA, Kiran K.; LI, Dong-Ming; LEI, Fu-Min; WINGFIELD, John C.; Univ. of Washington, Seattle; Univ. of Washington, Seattle; Virginia Tech, Blacksburg; Univ. of California, Los Angels; Inst. of Zoology, Chinese Academy of Sciences; Inst. of Zoology, Chinese Academy of Sciences; Univ. of Washington, Seattle gangw@u.washington.edu
The Arctic tundra and Tibet Plateau are considered extreme environments but they differ in latitude and altitude respectively. Many studies have addressed adaptations of hormone-behavior interactions to unpredictable environments in Arctic birds, especially regulation of the hypothalamic-pituitary-adrenal (HPA) axis. These modulations are thought to enhance reproductive success under severe conditions. Whether similar modulations of the HPA axis occur in major high altitude environments is less well known. In this study, we investigated the baseline and stress induced levels of corticosterone in relation to season and year in two species of snowfinch: white-rumped snowfinch (WRSF), Onychostruthus taczanowskii and rufous-necked snowfinch (RNSF), Pyrgilauda ruficollis, which are endemic to the Tibet Plateau from 3000�5000 meters elevation. Baseline and stress-induced levels of corticosterone were significantly higher during spring than autumn in WRSF, but not in RNSF. An abnormal cold spring in 2005 delayed onset of breeding in WRSF. In contrast, RNSF were already mated and were building nests at this time. It is unclear whether this is due to RNSF being more resistant to low temperature or whether regulation of breeding seasons is different between these two snowfinch species. WRSF did show seasonal regulation of both baseline and stress induced level of corticosterone, similar to Arctic birds. However, RNSF, often breeding alongside WRSF, did not modulate. Whether this represents a species difference or is related to differences in breeding phenology is currently under investigation.
