Genetic differentiation of continental and island populations of Bombus terrestris (Hymenoptera: Apidae) in Europe

Abstract

Ten microsatellite loci and a partial sequence of the COII mitochondrial gene were used to investigate genetic differentiation in B. terrestris, a bumble bee of interest for its high-value crop pollination. The analysis included eight populations from the European continent, five from Mediterranean islands (six subspecies altogether) and one from Tenerife (initially described as a colour form of B. terrestris but recently considered as a separate species, B. canariensis). Eight of the 10 microsatellite loci displayed high levels of polymorphism in most populations. In B. terrestris populations, the total number of alleles detected per polymorphic locus ranged from 3 to 16, with observed allelic diversity from 3.8 +/- 0.5 to 6.5 +/- 1.4 and average calculated heterozygosities from 0.41 +/- 0.09 to 0.65 +/- 0.07. B. canariensis showed a significantly lower average calculated heterozygosity (0.12 +/- 0.08) and observed allelic diversity (1.5 +/- 0.04) as compared to both continental and island populations of B. terrestris. No significant differentiation was found among populations of B. terrestris from the European continent. In contrast, island populations were all significantly and most of them strongly differentiated from continental populations. B. terrestris mitochondrial DNA is characterized by a low nucleotide diversity: 0.18% +/- 0.07%, 0.20% +/- 0.04% and 0.27% +/- 0.04% for the continental populations, the island populations and all populations together, respectively. The only haplotype found in the Tenerife population differs by a single nucleotide substitution from the most common continental haplotype of B. terrestris. This situation, identical to that of Tyrrhenian islands populations and quite different from that of B. lucorum (15 substitutions between terrestris and lucorum mtDNA) casts doubts on the species status of B. canariensis. The large genetic distance between the Tenerife and B. terrestris populations estimated from microsatellite data result, most probably, from a severe bottleneck in the Canary island population. Microsatellite and mitochondrial DNA data call for the protection of the island populations of B. terrestris against importation of bumble bees of foreign origin which are used as crop pollinators.

Protein-poor diet reduces host-specific immune gene expression in Bombus terrestris

“…However, the persistence of this effect into the second laboratory generation-as shown here-is more suggestive of a site-specific adaptation of the bees' gene expression patterns. This possible sign of local adaptation is especially noteworthy as the European B. terrestris population is panmictic [51,52]. The direction of the site effect differed among genes (electronic supplementary material, figure S3), whereas in the previous study [31], bees from Neunforn showed higher immune gene expression levels than bees from Aesch for all significantly differently expressed genes.…”

“…We did not test the genetic diversity of our populations and any such differences may explain some of the differences we see between our two populations. However, given that all mainland European B. terrestris appear to be part of a single panmictic population [51,52], and the lack of any geographical barriers to gene flow between these populations, suggests that these two populations should not differ greatly in diversity.…”

Discrimination of haploid and diploid males of Bombus terrestris (Hymenoptera; Apidae) based on wing shape

“…As a consequence, the colony produces only half the normal quantity of workers from the start and thus will remain rather small in size, with low production of new queens. Second, as most bumble bee species are monandrous (even known polyandrous species mate with a frequency close to one; Estoup et al 1996;Payne et al 2003;Takahashi et al 2008) and diploid males produce diploid sperm, queens mating with diploid males produce 100 % of sterile triploid offspring leading to the inbred strain having much lower fitness than outbred colonies. In wild populations, this is known as the Bdiploid male extinction vortex^ (Zayed and Packer 2005).…”

Interspecific Hybridization of the Korean Native Bumblebee Bombus hypocrita sapporoensia and the European Bumblebee B. terrestris

“…The large bumblebee Bombus terrestris is naturally distributed in Europe and adjacent territories, including England, most of Scotland, the north coast of Africa, southern Scandinavia, major Mediterranean islands, and some Atlantic islands (Madeira and the Canary Islands) (Estoup et al, 1996;Chittka et al, 2004;Velthuis and van Doorn, 2006). Since 1987, B. terrestris has been available commercially in portable boxes for crop pollination (Mitsuhata, 2000).…”