Seasonal observation of Drosophila in Niigata City

Abstract

Seasonal observation on the occurrence of Drosophila spp. was carried out in Niigata City. Collection was made by banana-trap and 18 species of 4 genera under 2 families were obtained from April to November in 1957. Among them Drosophila auraria, D. immigrance and D. lutea occupied remarkably in number and showed single or double peaks of population. One of the peaks was observed similarly in those three species at the middle of July, and another was at the end of October in D. immigrance and early in November in D. lutea. Most of specimens of other species were captured mainly in the fall. A great occurrences of D. virilis were observed after rainy season of early summer in 1960 and 1961.