Meeting Abstract

P3.154  Tuesday, Jan. 6  Acoustic signaling and temperature variations: their effects on the physiology and hatching synchrony of the developing avian embryo REYNA, K.S.; University of North Texas Reyna@unt.edu

Hatching synchrony is a strategy utilized by some oviparous vertebrates to maximize hatchling survival particularly in threatening environments. In many precocial birds hens lay one egg per day until their clutch is complete (laying asynchrony) yet members of the clutch hatch within a short period of time (typically within 10% of incubation time; i.e., hatching synchrony). Various laboratory studies attribute this phenomenon to acoustic signaling among adjacent embryos; however, no investigation has been done under simulated natural conditions. In quail species, and most distinctly in the Northern bobwhite (Colinus virginianus), the time difference between the first and last egg laid is typically 14 days. In the northern portion of the bobwhites range it is believed that embryos experience developmental diapause or torpor as ambient temperatures rarely exceed physiological zero (24C) during the pre-incubation period. However, in their southern range nest temperatures have been shown to exceed incubation temperature for most of the day, indicating that development must be occurring during the pre-incubation period. Accordingly, earlier laid embryos must synchronize their development with later laid embryos in order to hatch simultaneously or developmental asynchrony might occur in spite of hatching synchrony. I hypothesize that acoustic signaling among embryos of a clutch stimulates later laid eggs to accelerate development by increasing heart and metabolic rate; however, due to high temperatures experienced during the pre-incubation period I speculate that embryos will exhibit developmental asynchrony at the time of hatching. Underdeveloped hatchlings may be more prone to predation or less fecund leading to population declines.