Tropicomyia vigneae

Tropicomyia vigneae (Séguy, 1951)

Identification of Tropicomyia species is very difficult. Many species differ only in very slight characters of the male aedeagus. Moreover, due to insufficient availability of type material the status of several species is not fully clarified. Hence in most cases an approximation to the species can only be achieved by the comparison of pictures of the male genitalia (see also the Genus Tropicomyia) and, to some extend also the geographical range. Identification by external characters only is absolutely impossible.

Male terminalia
Hypandrial triangle short relative to the aedeagal apodeme, the frame is of intermediate thickness, hypandrial apodeme present. Aedeagus is shown in (Tr vigneae aedeagus dor.pct, Tr vigneae aedeagus Sp.pct). Basiphallus distinctly sclerotized at margins (or with sclerotized frame). Distiphallus subapically bifid, with thin hyaline apex.
Immature stages
Larval mouthparts of somewhat unusual shape within this genus. Posterior spiracles with about 7 bulbs each (Spencer, 1973).

This species belongs to the small group of epidermal feeders, a rather unusual feeding habit within the Agromyzidae. Life cycle and bionomics was studied by Beri, 1982 on the host plant Lablab niger (probably with natural temperatures): The eggs are normally laid on the lower surface of the leaf. After hatching, the larva feeds likewise on the lower side until the first moult. Than the larva migrates to the upper surface. The egg incubates about 3 days; the larval development lasts 6-7 days. The imago emerges after a pupation time of 11-12 days. In India imagines were mainly found from September until March. This long period indicates several generations in one season.

Vigna angivensis Baker, V. mungo L., V. unguiculata (L.), Glycine javanica L., Lablab purpureus (= L. niger, =Dolichos lablab L.), Dolichos gibbosus Thbg. (Spencer, 1973).

Madagascar, Sudan, Cape Verde Isl., India, Indonesia (Spencer, 1973).

Although the species feeds on some important cultivated crops, serious damage is not yet recorded.