Genetic signature of a recent southern range shift in Glossina tachinoides in East Burkina Faso.

In the eastern part of Burkina-Faso, the riverine tsetse fly, Glossina tachinoides Westwood, transmits African animal trypanosomosis that constitute a major constraint to sub-Saharan agriculture. To organize an efficient vector control campaign against this vector, it is crucial to identify and target isolated populations in order to prevent any risk of reinvasion. Previous entomological data using traps in this part of the country have suggested that G. tachinoides has now become discontinuously distributed with a western and an eastern tsetse belt. In this paper, we studied population genetics on G. tachinoides trapped in two sites, separated by 150 kms, on the western and eastern sides of this "gap". We found that a significant differentiation does exist between the two sites and that it is fairly above than what was expected given the geographic distance. A comparison between observed and expected differentiation allowed estimating that the total separation between these two sites could have occurred around 10 years ago (i.e. between 1 and 21 years), which is in line with the dates of environmental changes that occurred in this area. This result will help the national PATTEC project to organize the tsetse eradication in this area.