Postembryoiiic Reproductive-Systems Development in Empoasca fabae12

Abstract

The reproductive system of the adult female of Empoasca fabae (Harris) consists of 2 ovaries (each composed of 4 telotrophic ovarioles), lateral oviducts, a median oviduct, and a genital chamber bearing a pair of spermatozoal pouches, a spermatheca, and a median accessory gland. The ovaries and lateral oviducts are derived from 3 primary mesodermal tissues: the anterior ovarian strands, the primary epithelial sheaths, and the posterior ovarian strands. The median oviduct, genital chamber, spermatheca, and accessory gland originate during the second stadium. The median oviduct does not arise as an invagination during postembryogenesis, but develops from an ectodermal ampulla. The genital chamber invaginates from a posterior membranous portion on the venter of segment 8 and during the fifth stadium its anterior part extends over the posterior portion of the median oviduct producing 2 folds that form the definitive spermatozoal pouches. The spermatheca originates as an evagination near the opening of the genital chamber. The accessory gland invaginates between the second and third valvular rudiments on the venter of segment 9. The venter of segment 9 invaginates during the fifth stadium, and forms the posterior wall of the genital opening. The female genitalia consist of 3 pairs of valvulae derived from 2 primary-rudiment pairs on the venter of segments 8 and 9 of first-instar nymphs. The first valvulae arise from the anterior pair, whereas the second and third valvulae are secondary lobes of the posterior pair. The definitive first and second valvulae with anterior rami form the ovipositor; the third valvulae form ovipositor sheaths. A ramal sac is formed from invaginated sternum 8. The reproductive system of the adult male consists of 2 testes (each composed of 4 follicles), vasa deferentia with seminal vesicles, paired ejaculatory ducts, paired accessory glands, and a median ejaculatory bulb. The testes and vasa deferentia are derived from 2 primary mesodermal tissues, primary epithelial sheaths, and proximal strands. The accessory glands, ejaculatory ducts, and ejaculatory bulb do not arise from invaginations during postembryogenesis, but develop from an ectodermal ampulla during the third stadium. The male genitalia (aedeagus and lateral and median parameres) are derived from a pair of primary phallic rudiments on the venter of segment 9. Genital plates are derived from an anterior primary-rudiment pair on the venter of segment 9. The aedeagus arises from a pair of mesomeres, formed during the third stadium, which fuse during the fourth stadium into a single, median organ coincident with the formation of the lateral and median parameres. Yolk-laden primary oocytes are discharged from the ovarioles by the fourth to sixth day of the adult stadium. Spermatozoa are present in the seminal vesicles of males during the first day of the adult stadium.