Effect of incubation temperature on phenotype in mallard

The influence of incubation temperature on bird neonate phenotype is widely studied. In waterfowl (Anatidae), maternal effect can be divided to two main parts: clutch formation and its incubation. Therefore, waterfowl are a good model for this type of study. The egg temperature can strongly influence embryo development and survival of the hatchlings. The goal of this work was to examine the effect of incubation temperature on hatchability, incubation length, sex ratio and phenotype of European Mallard ducklings immediately after hatching. Eggs were randomly placed in one of six incubation temperatures, which ranged from 35 to 39 řC. This range corresponds with temperature range in natural mallard nests in the Czech Republic. Eggs were then artificially incubated. Newborn hatchlings were weighted and their structural size was measured, then they were killed. Some hatchlings from incubation temperatures 35.5, 36 and 37 řC were used to examine residual yolk sac mass and basic chemical composition of the yolk-free body. Hatchability was markedly lower in both extreme temperatures (35 and 39 řC). Incubation length significantly decreased with increasing incubation temperature. I failed to prove the influence of incubation temperature on hatchling body mass, but I found temperature-dependent changes of..