The Pattern of spontaneous activity in the tsetse flyGlossina morsitansWestw. (Diptera, Glossinidae) at low temperatures

Abstract The pattern of spontaneous activity of the tsetse flyGlossina morsitansWestw. was measured in LD 12:12 at constant low temperature. At 22°C the typical V-shaped pattern was unchanged; at 19°C, when activity was reduced to five flights per day, the morning arm of the V was retained but the evening one suppressed. Cold therefore changes the shape of the endogenous rhythm only slightly, and its effects in the field must concern activity level rather than pattern. Examination of the published data shows that the correlation of field activity with temperature is not as good as is generally supposed.