Population structuring of the tsetse Glossina tachinoides resulting from landscape fragmentation in the Mouhoun River basin, Burkina Faso

Abstract

Abstract. The impact of landscape fragmentation resulting from human-and climatemediated factors on the structure of a population of Glossina tachinoides Westwood (Diptera: Glossinidae) in the Mouhoun River basin, Burkina Faso, was investigated. Allele frequencies at five microsatellite loci were compared in four populations. The average distance between samples was 72 km. The sampling points traversed an ecological cline in terms of rainfall and riverine forest ecotype, along a river loop that enlarged from upstream to downstream. Microsatellite DNA demonstrated no structuring among the groups studied (F ST = 0.015, P = 0.07), which is contrary to findings pertaining to Glossina palpalis gambiensis Vanderplank in the same geographical area. The populations of G. tachinoides showed complete panmixia (F IS = 0, P = 0.5 for the whole sample) and no genetic differentiation among populations or global positioning system trap locations. This is in line with the results of dispersal studies which indicated higher diffusion coefficients for G. tachinoides than for G. p. gambiensis. The impact of these findings is discussed within the framework of control campaigns currently promoted by the Pan African Tsetse and Trypanosomosis Eradication Campaign.

Spatio-temporal distribution of tsetse and other biting flies in the Mouhoun River basin, Burkina Faso

“…At the most disturbed site, the few tsetse captured during the rainy season may have been flies dispersing from more conserved areas, as suggested by the absence of genetic structure between populations at Douroula and Boromo (Koné et al, 2010).…”

“…agrestis. Immigration of G. tachinoides, as demonstrated using genetic analyses (Koné et al, 2010), may have introduced the parasite. Atylotus agrestis, which was unequivocally shown to transmit T. vivax at a high rate in experimental conditions in the same geographic area (63% in 13-20 days) (Desquesnes & Dia, 2004), may then have amplified transmission of the parasite.…”

“…Cropping, especially of food crops or cotton (Gossypium hirsutum L.), carried out for 500 m either side of the river course, causes the disturbance of gallery forests, which has a negative impact on tsetse densities (de la Guerrini et al, 2008). The fragmentation may also reduce G. p. gambiensis dispersal capacities, so that populations are structured at microgeographic scales Solano et al, 2010a), whereas G. tachinoides, which is more xerophylous, is more resilient and harbours a panmictic population (Koné et al, 2010).…”

Effect of sampling methods, effective population size and migration rate estimation in Glossina palpalis palpalis from Cameroon

“…In population genetics studies of tsetse flies using microsatellite markers, heterozygote deficits have frequently been reported Kone et al, 2010Kone et al, , 2011Mélachio et al, 2011;Ravel et al, 2007;Solano et al, 2000Solano et al, , 2009. In these studies, the use of several methods of analysis have shown that the Wahlund effect, the presence of null alleles and of short alleles dominance were probable sources of the artificial heterozygote deficits.…”

“…G. tachinoides population sizes seem to be relatively large with important migration rates and effective population sizes, probably due to their greater ecologic tolerance, i.e. xerophily (Kone et al, 2010(Kone et al, , 2011. On the contrary, reproductive units seem smaller in Glossina palpalis sub-species, to the extent that samples from nearby traps belong to several different populations Kone et al, 2011;Ravel et al, 2007;Solano et al, 2000Solano et al, , 2009.…”