Gametogenesis in the Sugarcane Borer Moth, Diatraea saccharalis (F.) (Crambidae)

Abstract

Diatraea saccharalis (F.), the only cytologically checked crambid moth up to the present, has an unusually low chromosome number for a lepidopteran, n = 17. The chromosomes apparently have a diffuse centromere. The premeiotic development of the gonads becomes more distinct after the fifth larval day, when the secondary gonia appear. The oogenesis proceeds very slowly after the formation of oocytes. A rapid deposition of yolk starts at the end of the pupal stage, and continues in the adult. The eggs flatten before they leave the body of the female. Meiotic metaphases can be encountered in the flat ovarial eggs. Six successive generations of spermatogonia are formed. Meiosis starts in the basal end of the testis follicles, opposite Verson's cell. From the fifth day on the larvae contain all stages of spermatogenesis, from the gonia to the spermiohistogenesis. A normal meiosis occurs during this period. The meiosis is abortive in the male pupa, because of asynapsis and anaphase irregularities. Bundles of spermatozoa appear as result of the spermiohistogenesis. The divisions are completed in the adult male. The testes are partly drained, but contain spermatids in spermiohistogenesis, and spermatozoon bundles.