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Genetic structure and origin of B usseola fusca populations in Cameroon
Author(s) -
Sezonlin Michel,
Ndemah Rose,
Goergen Georg,
Le Rü Bruno,
Dupas Stéphane,
Silvain JeanFrançois
Publication year - 2012
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/j.1570-7458.2012.01319.x
Subject(s) - biology , clade , genetic diversity , vegetation (pathology) , botany , ecology , phylogenetics , population , genetics , gene , demography , sociology , medicine , pathology
The cereal stem borer B usseola fusca F uller ( L epidoptera: N octuidae) is a species endemic to sub‐ S aharan A frica. It is a major pest of maize and cultivated sorghum, the main cereal crops on the A frican mainland. Previous studies using mitochondrial markers revealed the presence of three clades of haplotypes (W, KI , KII ) among B . fusca populations. Previous preliminary studies based on a few B . fusca individuals collected from three localities within the G uineo‐ C ongolian rain forest in C ameroon demonstrated a matching with clade KII , a fairly surprising result because the putative centre of origin of that clade is located 3 000 km away in E ast A frica. To check this finding, 120 individuals of B . fusca covering several C ameroonian sites belonging to both G uineo‐ C ongolian rain forest and A fromontane vegetation mosaics were collected. Comparison of cytochrome b sequences using the same marker revealed low mitochondrial diversity (h = 0.483 ± 0.054, π = 0.073 ± 0.061%). Moreover, molecular diversity in the G uineo‐ C ongolian rain forest zone was lower than that in A fromontane vegetation, which is therefore thought to be the likely starting point for the colonization of other zones in C ameroon. The study showed a moderate but significant structuring between populations (Φ ST = 0.034, P<0.001) as well as within and among the two C ameroonian phytogeographical groups considered (Φ SC = 0.000 and Φ CT = 0.051, respectively, both P<0.001). Nested clade phylogeographic analysis indicated that all C ameroonian clades with significant geographical associations were interpreted as a phenomenon of contiguous range expansion. All results suggest that the C ameroonian population of B . fusca is relatively recent and originates from the recent geographical expansion of clade KII .