Biosystematics of the Muellerianella complex (Homopters, Delphacidae), hybridization studies

Abstract

Crosses were made between three closely related species of the planthopper genus Muellerianella, M. brevipennis, M. extrusa and M. fairmairei. Most hybrids are produced in crosses between M. extrusa and M. fairmairei. Most of the hybrid females in these crosses and some of the hybrid males are fertile and can be successfully backcrossed with the parental species. Crosses of M. brevipennis with either M. fairmairei or M. extrusa yield less progeny, of which all males are sterile. Backcrosses of the hybrid females with the parental species are partly successful. The possible evolutionary consequences of mating readiness and interfertility between the three species under field conditions are discussed. Efforts to resynthesize triploid gynogenetic forms by backcrossing hybrid females of M. fairmairei and M. brevipennis with males of M. fairmairei, as was reported by Drosopoulos (Evolution 32: 916–920, 1978), failed. To produce offspring, the existing gynogenetic forms have to mate with males of one of the three bisexual species.