Abstract
A paedogenetic gall midge, Mycophila sp., which feeds on the mycelium of, the oyster mushroom, Pleurotus ostreatus, was observed in 1984 in a factory in Miyazaki Prefecture. This species was completely eradicated from the factory by the application of an insecticide. Some of the larvae were transferred to the laboratory before the application and have been reared for successive generations in order to study their ecological and physiological characteristics. By using these materials, several experiments were carried out in July 1987 and January 1988 to obtain information about the phototaxis and movement of the species. Adults in a darkened test-tube covered with aluminiumfoilwere strongly attracted to the light coming through a small window opened around the centre of the test-tube. In contrast to the adults, the paedogenetic mother larvae which were put on a sheet of moistened white paper did not exhibit a distinct positive phototaxis under unidirectional lighting. They neither moved in any particular direction under uniform lighting, nor did they show any difference in the level of activity between dark and light places. The average moving distance of the larvae was about 11mm per minute.
