Apyrene Spermatogenesis in Ostrinia nubilalis (Hübner): Obligate and Facultative Diapausing Strains

Abstract
Four geographic strains of Ostrinia nubilalis (Hübner) differing in diapause characteristics were examined cytologically. Facultative diapausing strains from Georgia, Iowa, and Del aware were compared with an obligate diapausing population from North Dakota/ Minnesota (Red River Valley). The normal sequence of spermatogenesis was followed in facultative diapausing strains. Eupyrene (nucleate) spermatogenesis preceded apyrene (anucleate) spermatogenesis. The timing of production of these two types of sperm was reversed in the obligate diapausing strain, in which apyrene preceded eupyrene spermatogenesis.