Hormonal control of a seasonal polyphenism in Precis coenia (Lepidoptera: Nymphalidae)

Adults of the buckeye butterfly, Precis coenia, exhibit a seasonal color polyphenism. During the late spring and summer, under high temperatures and long photoperiods, the ventral surface of the hind wing and that of the exposed portion of the fore wing are a light beige (the linea form), while in the autumn, under low temperatures and short photoperiods, these wing surfaces are a dark reddish-brown (the rosa form). Removal of the brain immediately after pupation causes all animals to develop the rosa phenotype, irrespective of environmental conditions. The linea phenotype can be restored in brainless animals by injection of 20-hydroxyecdysone, and this response is dose-dependent. The critical period of sensitivity to ecdysteroids falls between 28 and 48 h after pupation. Measurement of ecdysteroid titers revealed that under long-day conditions ecdysteroid titers begin to rise 20 h after pupation, while under short-day conditions ecdysteroid titers do not begin to rise until 60 h after pupation, well after the ecdysteroid-critical period is over. © 1995.

Duke Scholars

Author H. Frederik Nijhout Biology