Meeting Abstract
In many oviparous species, incubation temperature plays an important role in the energy use of developing embryos and their hatching success. Although birds are endothermic after hatching, embryos generate little body heat and thus metabolism is closely tied to incubation temperature. For several decades, bobwhite quail populations have steadily decreased throughout most of their range. Loss of habitat and unfavorable nesting conditions (e.g., temperature) are likely causes. This study examined the effects of temperature on developing Northern Bobwhite quail embryos (Colinus virginianus). Eggs were incubated at one of four temperatures (35.5C, 36.5C, 37.5C, 38.5C). After the first week of incubation, metabolic rates (oxygen consumption) were recorded twice weekly from randomly selected eggs at each treatment temperature. Metabolic rate was positively correlated to incubation temperature and time. Rates increased significantly across the incubation period and embryos at higher temperatures had significantly greater metabolic rates than those at lower temperatures. Hatching rates decreased with decreasing temperatures while time to hatching decreased with increasing incubation temperature. Chick yolk-free dry mass and tarsus length increased while residual yolk dry mass decreased with increasing incubation temperature. Egg dimensions are good predictors of chick mass, although egg width has a stronger correlation than does egg length to chick mass. In summary, incubation temperature effects a developing embryo’s metabolism and thus energy use, which may ultimately determine hatching morphology and other life history traits.
