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The biology of nineteen taxa of African Stomoxyinae was studied during experiments with odour-baited Vavoua traps in Nairobi National Park, Kenya. Both male and female Stomoxys were captured in similar numbers with CO2 released at 2 l/min or octenol released at 2 mg/h. Some species of Haematobosca reacted synergistically to a combination of these attractants, producing large increases in catch. Stygeromyia and Rhinomusca responded only to CO2 and Prostomoxys did not respond to either bait. Many different activity patterns were documented in these genera, but most activity was concentrated just prior to sunset. For example, at peak densities nearly 1500 Stomoxyinae representing fourteen taxa were caught in a single trap between 18.00 and 19.00 hours. The Stomoxyinae community was exceptionally diverse when compared with other biting fly communities. Using data from traps set with different odour baits in the park forest, Shannon-Wiener diversity indices (H') varied from 2.5 to 2.8, and evenness (J') varied between 0.61 and 0.68. The Stomoxys population was extremely female-biased at the start of the rainy season, with species such as S. inornatus and S. boueti consisting of nearly 100% females. Sex ratios equalized when the first rainy-season generation emerged. population doubling times estimated from trap indices were approximately 12-16 days in two habitats (forest and riverine woodland).

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.

The responses of male tsetse Glossina austeni Newstead (Diptera: Glossinidae) towards blue and white sticky legged panels, baited with odour attractants, and towards modified panels were studied in the Jozani forest of Unguja Island, Zanzibar. Increasing the height of the body of a standard panel from 30 to 60 or 90 cm, increased the catch two-fold. Increasing the height of the legs (from 15 to 60 or 120 cm) or raising the device more than 5 cm above the ground reduced the catch significantly. The legs of the panels were the preferred landing sites of the flies, irrespective of the height of the body of the panel. Acetone (300 mg/h) combined with cow urine (60-130 mg/h) significantly increased the catches two- to threefold during the rainy season, but not during the dry season. Acetone had no effect during the dry season and its effect during the rainy season was less consistent. There was no effect of octenol (2.5-12.5 mg/h), used alone or in combination with acetone. Likewise, the catch did not increase through the addition of cow sebum, pig urine (60-860 mg/h), pig urine combined with acetone and octenol. The observed seasonal differences in the response of G. austeni towards odours are discussed in relation to host location strategies.

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