REPRODUCTIVE ISOLATION BETWEEN ANASTREPHA-BISTRIGATA AND ANASTREPHA-STRIATA (DIPTERA, TEPHRITIDAE)

The reproductive isolation between two closely related species, Anastr epha bistrigata and A. striata, was studied in the laboratory. Interes pecific copulation attempts were observed, but examination of the sper mathecae showed that sperm transference did not occur, even after a pr olonged period of contact between the mating pairs. These results indi cate prezygotic isolation. The analysis of the hourly distribution of mating activities under laboratory conditions, here described for the first time for A. bistrigata, clearly showed differences for the two s pecies, the activities being concentrated in the afternoon period for A. striata and in the morning for A. bistrigata.