Mating interactions between okra and cassava biotypes of Bemisia tabaci (Homoptera: Aleyrodidae) on eggplant

Abstract

Genetic and biological implications from interbreeding the Ghanaian okra and cassava biotypes of Bemisia tabaci (Gennadius), reared on eggplant, were studied in reciprocal crossing plans and crosses compared with parental generations using RAPD-PCR. Interbreeding did not affect fecundity of mated females and survival of F1 progeny. However, the sex ratio of the hybrid progeny was significantly male dominated (by 70% males) compared to purebred progeny of each biotype (>60% females) (P < 0.01). Each biotype was characterized by its own RAPD profiles. Hybrid females had one locus identical to that of both parents, while the males resembled the mother biotype at two loci. The F1 females were oviposited normally and there was a possible restricted gene flow between insects from the two biotypes, sharing the same host plant. However, the biological isolation seems to buttress ecological isolation in nature, hence maintaining the genetic and biological identity of sympatric populations in both biotypes. © ICIPE 2005.