Invasion of rooms by small flying insects and their responses to an adhesive light trap

Abstract

It has already been reported that moth flies, chironomid midges, fungus gnats, gall midges, and small plant-hoppers, as well as small moths, are the dominant room invaders under the operation of the ventilation fan in an adjacent room even on different observation dates. Experiments were conducted under the same conditions to examine the responses of invading insects to an adhesive light trap placed in the room. The intensity of their response to the trap (the number of insects caught on the trap/total number of insects invading the room) was examined for each species or group of insects. The intensity was varied from species (group) to species (group), ranging from 0 to 100%. All individuals of scuttle flies, small plant-hoppers, anthocorid bugs (small hemipteran bugs), and small rove beetles were caught on the trap, whereas few or no individuals of the large moth fly (Clogmia albipunctata), a chironomid midge (Chironomus yoshimatsui), crane-flies, whiteflies were caught on the trap. All or most individuals of the latter species (groups) were flying or staying on the wall or floor in the room, where they were hourly caught with an aspirator. In another series of the present experiments in a room where the ventilation fan was not operated, however, dominant outdoor insect species directly responding to an adhesive light trap in the room through a half-opened window varied among different days. They were manure flies, sand flies, smaller chironomid midges, or ants.