INFLUENCE OF PHOTOPERIOD AND TEMPERATURE ON DIAPAUSE IN FACE FLY MUSCA AUTUMNALIS (DIPTERA - MUSCIDAE)

The face fly, Musca autumnalis De Geer, exhibited true imaginal facultative diapause characterized by fat hypertrophy in both sexes and cessation of ovarian development in females. Adults were sensitive and responsive. Temperature and photoperiod influenced diapause induction. Continuous light and high temperature (83[degree]F) prevented diapause. Percent of flies diapausing increased as temperature was lowered and photoperiod shortened. Almost all flies diapaused when subjected to continuous dark at 65 [degree]F. Diapausing flies failed to feed on cow''s blood and failed to mate. Diapausing flies became photonegative and sought hibernation sites in holes of wooden blocks. Interruption of a 15-hour dark phase by a 2-hour supplementary light phase failed to produce a difference in diapause incidence.