Hemolymph Ecdysteroid Titers in the 5th Instar of the Oleander Hawk Moth, Deilephila nerii1: Relationship to Melanization and Pupation2

Publisher Website
Google Scholar
Abstract
An ecdysteroid-mediated pigmentation change from green to black occurs on the dorsum of all eight abdominal segments of 5th instars of the oleander hawk moth, Deilephila nerii (L.) (Lepidoptera: Sphingidae). High-pressure liquid chromatographic analyses of hemolymph ecdysteroid titers from various time periods within the 5th instar reveal that two ecdysteroid releases occur involving 20-hydroxyecdysone (β-ecdysone), the major ecdysteroid present. The first release precedes the appearance of the characteristic prodromal signs as well as synthesis and deposition of melanin, and may serve to trigger these events. The second release results in the processes of apolysis and ecdysis. A model is proposed presenting the basic mechanisms that may be involved in triggering the onset of melanization and pupation in this insect.