Effects of the entomopathogenic fungus metarhizium anisopliae on glossina fuscipes fuscipes in lake victoria island

Abstract

Glossina spp. Commonly known as tsetse flies are vectors of trypanosomes which can cause african human and animal trypanosomiases. The control of those diseases and their vector has shown some limitations. The 'dissemination technique' was considered to become a suitable method for tsetse control. It involves the contamination of flies with a lethal or sterilising agent and is based on the spread of the agent through natural contact events between tsetse flies. In the first part of the study, fluorescent pigment powder was used to detect whether there are regular contact events between specimens of g. Fuscipes fuscipes in the field. The results show that males regularly contact other flies. The contact rate per male and day was positively linear correlated with the apparent population density. With a few exceptions, the contact events occurred regardless of sex or age. That suggests that morphological differences between males and females are too small to be detected from the males. It suggests further that male tsetse flies are attracted preliminary visually and that they may finally identify the sex and the willingness via contact. However, there were preferences for the youngest and oldest females and a discrimination against the youngest males. That could have been caused by olfactory chemicals or the behaviour of the flies. Male tenerals and the oldest males in wing-fray category 6 did not contact other flies while males in wing-fray categories 2 - 5 were found to be most sexually active. In the second part of the study, it was to determine whether a particular application of the 'dissemination technique' was an alternative to trapping vi out. As a result, it was shown that maniania's contamination devices, which were contaminated with dry conidia of the entomopathogenic fungus metarhizium anisopliae and mounted on biconical traps, killed less flies than passing the cd's and hence, less flies than captured with the traps. That was because the infection rate of the cd was clearly less than 20 % and the number of infections through contact events between the flies too low to compensate that. Therefore, this particular application was found not to increase the efficiency of a trap. Hence, it is not an alternative to trapping.