Ecdysteroid profiles for hemolymph and testes from larvae, pupae, and pharate adults of the European corn borer, Ostrinia nubilalis hubner

Abstract

AbstractTotal ecdysteroid levels as well as concentrations of several individual ecdysteroids were determined for hemolymph and testes of fifth instars, pupae, and pharate adults of the European corn borer, Ostrinia nubilalis (Hubner). For total levels, the patterns of fluctuation in hemolymph and testes were similar, but the concentrations in testes were lower than those in hemolymph. In both hemolymph and testes there were two ecdysteroid peaks: the first just prior to the formation of the pharate pupa, the second just prior to the formation of the pharate adult.An examination of ecdysteroid profiles revealed some important differences. Ecdysone was either absent or present at extremely low levels in larval testes, whereas in hemolymph there was a premolt ecdysone peak. In pupal testes, ecdysone was present, but levels of 26‐hydroxyecdysone were much lower than those in hemolymph. Thus, in regard to ecdysteroids, testes have the ability to control their own internal milieu.