Genetic differentiation in the soil-feeding termite Cubitermes sp. affinis subarquatus: occurrence of cryptic species revealed by nuclear and mitochondrial markers.
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
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.
Roy
Virginie
V
UMR 137 Biosol, UFR de Sciences, Université Paris XII--Val de Marne, av, du Général de Gaulle, 94010 Créteil cedex, France. roy@univ-paris12.fr
Demanche
Christine
C
Livet
Alexandre
A
Harry
Myriam
M
D000818:Animals; D001483:Base Sequence; D021901:DNA, Intergenic / Q000032:analysis; D004272:DNA, Mitochondrial / Q000032:analysis; D005681:Gabon; D040961:Genetic Drift; D005819:Genetic Markers; D014644:Genetic Variation; D020049:Isoptera / Q000235:genetics*; D018895:Microsatellite Repeats; D008928:Mitochondria / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
D021901:DNA, Intergenic; D004272:DNA, Mitochondrial; D005819:Genetic Markers