Incubation temperature influences sex ratio and offspring’s body composition in Zebra Finches (Taeniopygia guttata)

Incubation temperature has the potential to influence offspring sex, phenotype, and survival, particularly in species with temperature-dependent sex determination. However, relatively little is known about how incubation temperature affects sex ratio and offspring condition in other animals. Incubating birds allocate varying time for egg incubation depending on the parents’ condition and ambient temperature, likely altering nest microclimate. To understand how incubation temperature impacts offspring phenotype in birds, we artificially incubated zebra finch ( Taeniopygia guttata (Vieillot, 1817)) eggs at 36.2, 37.4, or 38.4 oC during the entire incubation period and examined sex ratio and offspring quality. We found that incubation temperature of 36.2 oC resulted in a greater likelihood of a young being male compared to 37.4 oC, indicating that it is more likely for males to survive until the juvenile stage compared to females in the 36.2 oC group. We also found sex-specific effects of incubation te...