Meeting Abstract

90.5  Sunday, Jan. 6  Seasonal maternal effects on post-hatching growth and development in Franklin’s gull REED, W. L.*; CLARK, M. E.; North Dakota State University, Fargo; North Dakota State University, Fargo wendy.reed@ndsu.edu

Theoretical predictions and empirical evidence suggest that parental investments in offspring decrease across the breeding season. However, it is not well documented how offspring fitness responds to variation in seasonal timing of reproduction. Our hypothesis is that offspring respond to cues of season and adjust their phenotypes to maximize their fitness based on conditions at hatching. We evaluated the impact of seasonal changes in parental investment on offspring growth and development in common garden experiments with Franklin’s gull (Leucophaeus pipixcan), a long distance migrant. We previously documented that Franklin gull embryos are able to integrate cues of season from egg investments and photoperiod and can adjust growth and development during embryonic development. In this experiment we evaluated the impact of season and photoperiod during embryonic development on post-hatching growth and development. Freshly laid eggs were collected, incubated under photoperiods similar to early and late season, and chicks were reared in a common environment. The effects of photoperiod on development appear to be limited to embryonic development, but the maternal effects of season extend through the nestling period. Late season gull chicks grow faster, reach maximal growth rates at earlier ages, and reach lower peak masses than early season gull chicks. Early and late season chicks ultimately achieve similar asymptotic or final masses, which suggests that growth in late season chicks can compensate for a poor start.