Field responses of Glossina austeni to sticky panels on Unguja Island, Zanzibar.

Two designs of cross-shaped sticky panels (XT and XLP) were compared with the royal blue-white legpanel (LPBuWh) in the Jozani forest on Unguja Island as trapping devices for male Glossina austeni. Single coloured royal blue (XTBu) and bi-coloured royal blue-white XT (XTBuWh) caught more than twice as many male G. austeni as the LPBuWh, whereas single coloured black XT trapped significantly fewer flies (10%) than the control LPBuWh. XT's in various horizontal and diagonal blue-white configurations likewise trapped more flies than the LPBuWh, except a horizontally striped blue-white XT which trapped fivefold fewer flies than the LPBuWh. Cross-shaped LP in the blue-white (XLPBuWh) and black-white (XLPB1Wh) combination scored significantly better than the control LPBuWh. Similar fly numbers were trapped with XTBuWh and XLPBuWh. Long-term trapping data indicated that the XTBu, XTBuWh and XLPBuWh were three- to fourfold more effective in trapping female flies than the LPBuWh. The landing bias on bi-coloured panels was low in the blue-white but more pronounced in the blue-black and white-black combinations and was affected by the type of sticky panel used. A high proportion (49%) of the flies alighted on the bottom corners of the XTBu panel, but landing positions were more scattered if white was added. Increasing the width of the XTBu from 70 to 120 cm improved the catch by a factor of two as compared with standard sized XTBu. The effect of doubling the height of the XT on total fly catch was negligible. At present, it is the XTBu which can be recommended as the best trapping device for male and female G. austeni.