Seasonality and diel activity pattern of Glossina morsitans submorsitans ) (Diptera: Glossinidae) in Ghibe River Valley, Southwest Ethiopia

Aspects of the ecology of Glossina morsitans submorsitans inhabiting Ghibe River Valley was studied from October 2000 up to September 2001 with baited monoconical traps. The baits were acetone plus cow urine. Seasonality of the flies were investigated using baited monoconical traps by taking sample every month for five consecutive days for twelve months and diel activity pattern was investigated by taking sample every hour for three consecutive days. The density of G. m. submorsitans was found to be high during wet months and decrease during dry months. It was widely distributed during the rainy season in the savanna woodland; while its distribution was patchy during the dry season. G. m. submorsitans showed a bi-modal daily activity pattern with morning peak followed by mid day depression and then afternoon peak. Its activity rhythm showed a dual relation with temperature, positively correlated in the morning when the temperature is less than 30°C and negatively correlated when temperature is greater than 30°C. Its relation with relative humidity was also both positively and negatively correlated at different time of the day. Key words/phrases : Diel activity, Ghibe River Valley, G. m. submorsitans, seasonality, Southwest Ethiopia SINET: Ethiopian Journal of Science Vol. 27 (2) 2004: 135–142