A taxonomic review of Sturmiopsis Townsend, 1916, an Old World genus of Tachinidae (Diptera) parasitising economically significant lepidopterous stem borers

Abstract

Sturmiopsis Townsend is an important larval parasitoid of lepidopterous stem borers in the Afrotropical and Oriental Regions, and there is a substantial literature relating to the potential role of its included species as biological control agents of economically significant pest species. Two species have been described from Africa, namely Sturmiopsis angustifrons Mesnil, 1959, and S. parasitica (Curran, 1939), the latter distributed from Southern into East Africa, but also represented in West Africa. There has been uncertainty about whether S. angustifrons and S. parasitica are distinct species, and given the use of Sturmiopsis parasitica as a putative biocontrol agent of Eldana saccharina Walker, a pyralid stem borer which has had a considerable impact on the sugarcane industry, a taxonomic review of the genus was indicated. This paper provides a taxonomic review of Sturmiopsis, a generic diagnosis, and a detailed key to the three valid species. A careful study of Sturmiopsis specimens from localities throughout Africa revealed that it was impossible to distinguish S. angustifrons from S. parasitica, and consequently angustifrons is newly synonymised with parasitica. The two other valid Sturmiopsis species are S. inferens Townsend, 1916, which is widespread in the Oriental Region, and S. emdeni Mesnil, 1952, a little-known species currently known only from Israel. Sturmiopsis parasitica is redescribed; there appear to be two allopatric African populations, one from Southern and East Africa, and the other from West Africa. These populations are distinguished by subtle differences in the shape of the male surstylus in profile. The first known male of S. emdeni is recorded and described.