Genetic differentiation in the soil-feeding termite Cubitermes sp. affinis subarquatus: occurrence of cryptic species revealed by nuclear and mitochondrial markers
Virginie Roy1, Christine Demanche1,2, Alexandre Livet1 and Myriam Harry1
1UMR 137 Biosol, UFR de Sciences, Université Paris XII – Val de Marne, av. du Général de Gaulle, 94010 Créteil cedex, France
2Faculté de Pharmacie, Laboratoire de Parasitologie, 3 rue du Pr. Laguesse, 59006 Lille, France
Soil-feeding termites are particularly interesting models for studying the effects of fragmentation, a natural or anthropic phenomenon described as promoting genetic differentiation. However, studying the link between fragmentation and genetics requires a method for identifying species unambiguously, especially when morphological diagnostic characters are lacking. In humivorous termites, which contribute to the fertility of tropical soils, molecular taxonomy and phylogenetic relationships are rarely studied, though mitochondrial and nuclear molecular markers are widely used in studies of pest termites. Here, we attempt to clarify the taxonomy of soil-feeding colonies collected throughout the naturally fragmented Lopé Reserve area (Gabon) and morphologically affiliated to Cubitermes sp. affinis subarquatus. The mitochondrial gene of cytochrome oxidase II (COII), the second nuclear rDNA internal transcribed spacer (ITS2) and five microsatellites were analyzed in 19 colonies.
Bayesian Inference, Maximum Likelihood and Maximum Parsimony phylogenetic analyses, which were applied to the COII and ITS2 sequences, and Neighbor-Joining reconstructions, applied to the microsatellite data, reveal four major lineages in the Cubitermes sp. affinis subarquatus colonies. The concordant genealogical pattern of these unlinked markers strongly supports the existence of four cryptic species. Three are sympatric in the Reserve and are probably able to disperse within a mosaic of forests of variable ages and savannahs. One is limited to a very restricted gallery forest patch located in the North, outside the Reserve.
Our survey highlights the value of combined mitochondrial and nuclear markers for exploring unknown groups such as soil-feeding termites, and their relevance for resolving the taxonomy of organisms with ambiguous morphological diagnostic characters.
BMC Evolutionary Biology 2006, 6:102. This is an Open Access article distributed under the terms of the Creative Commons Attribution License.