Maternal investment in yolk hormones and carotenoids: sources of variation and effects in wild rockhopper penguins.

Mothers can influence the phenotype and performance of their offspring by adjusting their deposition of egg components to environmental conditions and according to their own physiological state. Birds, and rockhopper penguins (Eudyptes chrysocome) in particular, have excellent characteristics which can be used to study the sources of variation in maternal investment in eggs and their potential effects on embryonic survival and development. Rockhopper penguins exhibit a reversed egg size dimorphism, brood reduction, a unique reversed hatching asynchrony, and large differences in breeding success among years and populations. Therefore, I can study variation in maternal investment on all possible levels: within the population, within clutches and among seasons and populations. I will first explore the sources of variation in investment in eggs (in terms of layingdate, mass, and levels of androgens, carotenoids and antibodies) according to female quality (e.g. arrival and laying dates and weights, blood parameters). Various approaches will be used to examine the contribution of male quality. Effects on embryo survival and development will be studied mainly via experimental manipulation of androgen levels. Finally, my long-term study and collaboration with groups working on other rockhopper populations will enable assessment of inter-annual and populational variation in maternal investment.

Keywords:BEHAVIOURAL ECOLOGY

Disciplines:Animal biology, Veterinary medicine