REPRODUCTIVE BEHAVIOUR OF THE DOUGLAS-FIR CONE GALL MIDGE, CONTARINIA OREGONENSIS (DIPTERA: CECIDOMYIIDAE)
AbstractThe reproductive behaviour of the Douglas-fir cone gall midge, Contarinia oregonensis Foote, was studied in the laboratory and in cages outdoors. Adult emergence began in mid-April outdoors and lasted about 2 weeks. Emergence began outdoors at 0600–0700 h Pacific Standard Time, peaked at 1100 h and continued until 1900 h; females dominated emergence early in the day. Mating occurred on or near the duff from which females emerged. Virgin females appeared to “call” males by extending their ovipositors and waving them back and forth, and this behaviour was followed by mating. Laboratory bioassay s using rinses of female abdomens gave further evidence that virgin females produce a sex pheromone. Oviposition behaviour on already infested conelets differed from that on uninfested conelets and suggested the presence of an oviposition deterrent. The mean number of eggs developed by the females was 254, 93% of which were usually laid during the life of the females.