I've always been interested in understanding how mothers influence offspring phenotypes through investments they make during development (e.g., Reed and Vleck 2001, Reed et al. 2009). The egg environment provides all of the nutrients and material necessary for proper development, but it is clear that not all eggs are created equal. Females vary in the constitution of eggs they produce and eggs from different females, or even eggs produced by a single female, can differ in the amounts of biologically active compounds they contain like hormones, carotenoids, antibodies, RNA transcripts and vitamins. These compounds can affect development of the offspring and program offspring phenotypes into adulthood. I find the intersection between maternal (parental) and offspring fitness fascinating.
Currently, I am interested in how mothers change egg investments across the season and how offspring respond to these changes. In Franklin's gull we found that embryos from eggs laid late in the season are able to integrate cues of season from constituents in the egg as well as directly from photoperiod to produce phenotypes that grow very differently from one another (Clark and Reed 2012). Our hypothesis is that embryos use cues of season from eggs and photoperiod (Reed and Clark 2011) to produce phenotypes that are best suited (result in fitness benefits) for growth and development in the particular portion of the season in which they hatch. For long-distance migrants, like Franklin's gulls, late season chicks have a much shorter time in which to grow, develop, moult, learn to forage, fly and prepare for a long migration than early season chicks. In this situation we expect strong selection for late season chicks to grow rapidly and meet these milestones for a successful migration.