Population genetic structure and colonization history of Bombus terrestriss.l. (Hymenoptera : Apidae) from the Canary Islands and Madeira

The bumble bee Bombus terrestris L. is a geographically variable species wi th a wide distribution in Europe, the near East, northern Africa, Mediterra nean islands, the Canary Islands and Madeira. Based on morphological and co at colour pattern differences, the bumble bee populations of the Canary Isl ands and Madeira are currently treated as separate species, B. canariensis and B. maderensis, respectively. To analyse the phylogeographical associati ons of these bees with continental B. terrestris, one population each from four islands of the Canaries and one population from Madeira were studied. Genetic variability was assessed at nine microsatellite loci and a fragment of the mitochondrial gene cytochrome b. Genetic differentiation among isla nds, and between islands and the continent, was extensive. A NJ-tree based on microsatellites strongly supported the distinctness of the Canary Island populations, whereas the Madeira sample was genetically more similar to th e continental populations of B. terrestris from Europe. MtDNA sequence data were in good agreement with nuclear markers. They suggest that haplotypes ancestral with respect to B. lucorum occur on the Canary Islands, whereas d erived haplotypes were found on the European continent. The Madeira populat ion shares the most common haplotype of continental B. terrestris. Nuclear and mtDNA data both indicate that bumble bees from the Canaries and Madeira do not share a common colonization history.