Reproduction in a Parthenogenetic Aphid, Aphis Craccivora Koch: Embryology, Ovarian Development and Fecundity of Apterae and Alatae.

Abstract

The embryology of A. craccivora is described. Ovarian growth of apterous and alate morphs was compared. At maximum ovarian development, apterae contained significantly more oocytes and embryos than alatae, they achieved this maximum 1-2 days earlier, and their fully developed embryos were always larger than those in alatae. There was no significant variation in oocyte and embryo number between individuals of the same stage and morph, but considerable variation between corresponding embryos from different ovarioles in the one ovary. Total fecundity of individual apterous aphids (96 : 32) was significantly greater than that of alatae (84 : 08), although alatae had a much longer reproductive life (29.02 days) than apterae (21.52 days). The results are discussed in relation to the different life cycles and physiological requirements of the two morphs.