Morphology of the Internal Reproductive System of the Male and Female European Corn Borer Ostrinia Nubilalis (Hubner)

Abstract

The gross morphology of the internal reproductive organs of the adult male and female European corn borer is described. The adults were laboratory reared progeny and descended from wild specimens collected in the Rochester area, Western N.Y. The male system displayed 2 major variations in the paired vasa deferentia. In 8% of 75 recently emerged males, each of the ducts arising from the testis, had a single expansion before merging with the narrow portions of the ducts. These expansions have been referred to as the seminal vesicles or upper vasa deferentia. In 88% of the 75 males, the ducts showed 2 expansions; the single expansion immediately followed by a second, smaller expansion, shaped somewhat like a tear-drop. A stable, distinguishing characteristic of the male tract is the large flask-like or ampulliform extensions of the accessory glands. These bodies were found in all males upon dissection. The female reproductive tract showed fewer variations. However, this species on emergence shows a transparency of the spermathecal complex, the lateral oviducts, the common oviduct and the bursal duct. After insemination, only the bursal duct displays a transparency. The female emerges with unripe eggs and at this stage of development has the capacity to receive the spermatophore immediately after wing drying. The male was not observed to copulate until after the first or second day.