Meeting Abstract

S8.7  Thursday, Jan. 6  Beyond maternal effects on avian development: embryonic responses to the environment.ail REED, W.L.*; CLARK, M.E.; North Dakota State University, Fargo wendy.reed@ndsu.edu

Embryonic growth and development are impacted by environmental conditions. In avian systems parents often tightly control these environments through egg provisioning and incubation behaviors. Parents can influence offspring embryonic development through egg size, eggshell conductance, hormones or other substances deposited in eggs, incubation onset, incubation temperatures and humidity. In addition to these parental influences, avian embryos are able to perceive and actively respond to incubation environments and adjust their own development. Considerable evidence indicates that avian embryos are affected by maternally derived egg components. In addition to responding to maternal effects, avian embryos can perceive differences in day length and modify their development. The influence of photoperiod on avian development is best studied in the context of poultry health and husbandry, but our research indicates that photo-modulation of development also occurs in free-living populations of birds. The adaptive significance of embryo response to photoperiod is being explored. However, the fitness consequences of timing of hatching during the season are well established; birds hatching late in the season have less time to grow and develop before migration and are at a significant survival disadvantage relative to birds hatching early in the season. Our hypothesis is that these seasonal differences in fitness result in strong selection for embryos that can accurately evaluate time during the season and adjust their growth accordingly.