Meeting Abstract
Timing of breeding can be important indicator of offspring phenotype & survival in many regions. Offspring produced later in breeding season typically suffer lower survival. Because strong selection is associated with timing of breeding I expect breeding adults to have evolved mechanisms to respond to cues of season & therefore moderate seasonal cues they give to their offspring. Again, because strong selection exists, I expect offspring to also evolved mechanisms to receive, interpret, & respond to cues from both their mothers & environment. We are providing a tractable system to understand how organisms integrate these cues & communicate environmental information. Birds are often seasonal breeders making good models for exploring seasonal effects on timing of reproduction & development. In seasonal breeders, I hypothesize adults adjust offspring phenotype (i.e. egg shape, size, embryo growth) in accordance to timing of breeding, not solely to adult condition. I hypothesize their offspring integrate cues of season from environment (photoperiod) & mothers (hormones), resulting in seasonally different phenotypes (growth & hatch survival) adaptive for the timing of breeding season. To test these predictions, we monitored a breeding colony of Laughing Gulls (Leucophaeus atricilla). We observed nest initiation & egg laying. We trapped adults on observed nests to gather information about the breeding adult’s condition & physiology. Further, we collected first-laid eggs across the nesting season & incubated the eggs under experimental photoperiods (14 hr vs. 18 hr of light) to evaluate hatched chick phenotypes. By integrating seasonal information from adult, egg, & chick, we provide insight on the underlying mechanisms evolved to regulate offspring phenotype.
