The development of a multipurpose trap (the Nzi) for tsetse and other biting flies

New trap designs for tsetse (Glossinidae), stable flies (Stomoxyinae), and horse flies (Tabanidae) were tested in Latin-square experiments in Kenya in order to develop a multipurpose trap with harmonised efficiency all biting flies. Many configurations and colour/fabric combinations were compared to a simplified, blue-black triangular trap resembling the NG2F to identify features of design and materials that result in high and equitable catches across groups. New designs were tested and validated for a variety of species in many localities against conventional traps, with a focus on Glossina pallidpes and G. longipennis, Stomoxysniger sspp., and Atylotus agrestis. A relatively simple design based on minimal blue and black rectangular panels for attraction and contrast, framing a trap body consisting of an innovative configuration of transparent netting, proved best. This "Nzi" trap (Swahili for fly) caught as many or significantly more tsetse and biting flies than any standard trap. It represents a major improvement for Stomoxyinae, including the cosmopolitan species S. calcitrans, with up to eight times the catch for key African Stomoxys spp. relative to the best trap for this group (the Vavoua). Catches of many genera of Tabanidae, including species almost never caught in traps (Philoliche), are excellent, and are similar to those of larger traps designed for this purpose (the Canopy). Improvements for diverse biting flies were achieved without compromising efficiency for the important savannah tsetse species G. pallidipes. Catches of other fusca tsetse (G. longipennis and G. brevipalpis) were higher or were the same as catches in good traps for these species (NG2G, Siamese). Altogether, the objective of developing a simple, economical trap with harmonised efficiency for many kinds of tsetse and biting flies was achieved.