Meeting Abstract
Developmental environment can have a strong influence on phenotype of offspring. In birds, embryonic development is a crucial life history stage with incubation temperature playing a large role in determining individual phenotype. Incubating parents will modify their incubation behavior depending on their body condition and ambient temperature by exposing eggs to suboptimal temperatures. Many studies have assessed the effects of constant suboptimal incubation temperatures on phenotype, but little is known about how fluctuating incubation temperatures alter offspring phenotype. Similarly, only few studies have investigated long-term effect of incubation temperature on fitness-related measures. One fitness related trait in birds is beak coloration, a secondary sex characteristic that indicates health condition and influences successful mating for both males and females, which varies with age and sex. Here, we assessed how periodic cooling during embryonic development influences the development of beak coloration as zebra finches (Taeniopygia guttata) reach sexual maturity. Embryos were incubated at one of the three temperature regimes; constantly low (36.4°C), periodic temperature (average 36.4°C), and control (37.4°C) temperatures. The hue, intensity, and saturation of the beak color was then recorded every 15 days from post hatch day 45 to 90. In T. guttata, juveniles have dark black beaks which become bright red in males or bright orange in females. Differences in the rate of development of this coloration between treatments, and between sexes within a treatment may indicate sex specific responses to suboptimal incubation temperatures.
