Meeting Abstract

12.6  Monday, Jan. 4  Why do we know so little about mechanisms underlying avian reproduction? WILLIAMS, Tony D.; Simon Fraser Univ., Burnaby, Canada tdwillia@sfu.ca

Recent evolutionary analysis of large, long-term population studies’ data has shown that the traits which contribute most to individual variation in lifetime fitness in birds are longevity, clutch size and laying date (but not, for example, egg mass or chick growth). The critical importance of many of these traits, such as clutch size, has been recognised for over 60 years yet our current understanding of the physiological basis of variation in these key fitness-related traits remains poor. In this talk I will explore the reasons for this lack of progress, highlighting and contrasting the challenges and opportunities for specific life-history traits. For example, although there has been a large amount of experimental, physiological work on seasonal breeding we currently lack a basic model for the mechanism(s) underlying female control of onset of egg-laying (the key determinant of timing of breeding). In contrast, a very comprehensive model for physiological control of clutch size was proposed over 20 years ago but virtually no experimental work has been directed towards testing this model. Longevity (senescence) is a rare example of current mechanistic research being directed at a key life-history trait. Currently much of the research effort in avian physiological ecology is being directed at traits for which there is little or no evidence of long-term fitness consequences (e.g. minor egg components, such as hormones or antibodies). I aim to show how an evolutionary perspective should not only be driving our research focus, but should also dictate specific ecologically-relevant experimental design. Future progress in integrating avian evolutionary biology and physiology will require a major shift in research focus.