Temperature Increase Can Cause Hyperecdysonism in American Lobsters (Homarus americanus) Injected with Ecdysterone

Abstract

In the lobster Homarus americanus the threshold dose for premolt acceleration by ecdysterone can be altered by changes in temperature. Two dose levels of ecdysterone (0.5 and 1.0 μg/g body weight) were compared at three different temperatures (10, 17, 21 C); all three doses remained subthreshold at 10 C but at 17 C the 1.0-μg dose caused hyperecdysonism — rapid but abnormal completion of premolt terminating in death at ecdysis. In contrast, the 0.5-μg dose remained subthreshold even at 21 C. These results demonstrate a dose–temperature relation for response to injected ecdysterone.