Meeting Abstract
P2.156 Sunday, Jan. 5 15:30 The Effects of Maternal Stress on Offspring in the Zebra finch Taeniopygia guttata KHAN, N/Y*; ROBERT, K; La Trobe University, Melbourne; La Trobe University, Melbourne n2khan@students.latrobe.edu.au
The stress response of the hypothalamic–pituitary–adrenocortical feedback system allows adaptive reactions to environmental challenges, such as resource availability, extreme weather and predation attempts. Acute stressors mobilise energy stores and redirect energy towards survival at the expense of body processes, namely growth, reproduction, and immune responses. These effects are short-term, where the system rapidly returns to baseline. However, extended activation of the HPA feedback system can be detrimental, affecting long-term fitness via immunosuppression, impaired reproductive systems, and eventually, death. This study examines the effect of repeated bouts of maternal stress during egg development on offspring sex ratios, clutch size, fertility, hatching success, and growth rates. Female Zebra finches Taeniopygia guttata were given three doses of the stress hormone corticosterone (CORT) daily during egg-laying to imitate an unstable environment. This method ensures physiologically relevant peaks and troughs in CORT concentrations. Here we show Zebra finch mothers dosed orally with CORT produce slightly larger clutches, and fertility is unaffected by treatment. However, CORT-treated clutches show significantly poorer hatching success, and much lower fertile hatchability, in comparison to the control group. Interestingly, CORT-treated clutches tend to be heavier than control clutches throughout their development. Parents appear to be favouring daughters, as female chicks are consistently heavier than males throughout development in both treatment groups. However, once juveniles are nutritionally independent, males ‘catch up’ in weight, and remain a similar weight to their female counterparts. Future research is identifying potential trans-generational effects, and changes to parental incubation and provisioning behaviour.
