Probable natural hybrids of Nephotettix virescens (Distant) and N. nigropictus (Stal) (Hemiptera: Cicadellidae) from Sabah, Malaysia

Abstract

Hybrids of Nephotettix virescens (Dist.) and N. nigropictus (Stal) have been bred in the laboratory, and they could transmit rice tungro virus even though only one of the parents is a vector. In the present paper, evidence is presented based on coloration and on male genitalia that suggests that such hybrids occur in nature. The potential danger from such hybrid vectors is pointed out, and taxonomists are alerted to the risk of accepting such hybrids as new species, thus completely hiding their potential as vectors.A large number of specimens of Nephotettix collected by Dr. E. E. Tay from a light-trap at Sabah, Malaysia, on 20 November 1972 were sent to the Commonwealth Institute of Entomology for identification. This collection was found to be a mixture of N. virescens (Distant) (60 specimens) and iV. nigropictus (Stal) (15 specimens), but there was a third category of 30 specimens that were intermediate between these two species and showing variations in certain characters. Ling (1968) has described the morphological characters of hybrids of N. virescens and N. nigropictus bred in the laboratory. He showed that the hybrids could transmit rice tungro virus, even though one of the parents (N. nigropictus) is not a vector of this disease. Ling's findings confirm Storey's (1931Storey's ( , 1932 reports that the character of activity in transmitting plant virus by Cicadulina mbila (Naude) is genetically dominant to that of inactivity. These findings may be useful to research workers engaged in virus transmission studies for obtaining active colonies of insects, but the potential danger from such hybrids in nature is clear. Also, taxonomists who might take these hybrids for new species, thus completely hiding their potential as vectors, are alerted to this possibility.The various characters of these intermediate specimens that leads to the assumption that these are hybrids are given below. ColorationThe colour of both males and females is intermediate between that of virescens and nigropictus. The general colour of the head, pronotum, scutellum and tegmen is green with black markings as described below.Head. The submarginal black band on the vertex is completely absent in both sexes of virescens and present and well-developed in nigropictus. In the males in the series examined, the submarginal black band on the vertex is neither well-developed nor completely absent. It is partially developed and in most specimens is represented by somewhat crescent-shaped patch behind each ocellus. Ling (1968) made similar observations

Checklist and keys to Deltocephalinae leafhoppers (Hemiptera, Cicadellidae) from Pakistan

“…Nephotettix nigropictus yapicolaGhauri, 1971: 495. Nephotettix nigropictus: Ghauri, 1971 Vilbaste 1975: 233;Ramakrishnan and Ghauri 1979; Mahmood and Aziz 1979: 61, figs 1b, 3a-f (Pakistan);Duan and Zhang 2014: 219, pl. III; pl.…”