Wing length variation and seasonal changes in wing form composition of two Anaphothrips species (Thysanoptera: Thripidae).

Adults of Anaphothrips obscutus and A. asahi living on wild grasses and on Artemisia princeps were sampled from June 1991 to May 1992 and from March 1990 to March 1992, respectively, in Kyoto to clarify the variability in relative wing length and seasonal changes in wing form composition. On the grasses, the adults of the two thrips species were usually found from spring to autumn and occasionally in winter, but on A. princeps, they were only found from January to April and in October. Macropterous, brachypterous and intermediate forms were recognized in female A. obscurus. In early spring, most females were brachypterous, and the proportion of the macropterous females increased during late spring and late summer. In both sexes of A. asahi, only the brachypterous form occurred throughout the study period. The annual cycle and overwintering sites of these thrips species, and factors affecting the seasonal changes in wing form composition of A. obscutus are discussed.