Swarming and mating behaviour ofChironomus flaviplumus (Diptera: Chironomidae), compared with a sympatric congeneric species,C. yoshimatsui

The swarming and mating behaviour ofChironomus flaviplumus was observed and compared with a sympatric congeneric species,C. yoshimatsui. C. flaviplumus males swarmed around sunset near foliage or angles of buildings near the emergence site and copulated with females entering the swarm. Swarming and mating occurred under conditions of higher light intensity in cooler seasons than in warmer ones. Results suggested that temperature had an effect on the timing of flight to the swarming site in both sexes. TheC. flaviplumus swarm marker and swarming behaviour seemed very similar to that toC. yoshimatsui, and their respective daily swarming time zone greatly overlapped. No mixed swarm, however, was observed in the study area. This is probably due to the distance between the species' larval habitats. Possible premating isolation mechanisms between these 2 species are discussed.