Line V. Ugelvig, Klaus S. Petersen, Jes S. Pedersen, Jacobus J. Boomsma, and Sylvia Cremer. Department of Population Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
Dispersal in ants is normally linked to a mating flight, but invasive ants often mate within the nest and rely on human transport for long distance (jump) dispersal. We studied the colonization behavior of the most recently described pest ant, the invasive garden ant Lasius neglectus, and its non-invasive sister species Lasius turcicus. L. neglectus is currently spreading quickly throughout Eurasia, where it has now been reported from many urban sites. L. turcicus is, however, restricted to the Black Sea area, where its lowland populations are sympatric with L. neglectus whereas allopatric L. turcicus populations occur at higher altitudes. Mating experiments confirmed the hypothesized intra-nest mating behavior for L. neglectus (Van Loon et al. 1990. Ins. Soc. 37: 348-362) and showed, surprisingly, that the same mating behaviour is also common in the lowland form of L. turcicus. However, intra-nest mating did not occur in the highland populations of L. turcicus, and here we also regularly discovered independently founding queens, which indicates that dispersal happens through mating flights. Genetic analysis (microsatellites) confirmed that jump dispersal in L. neglectus has indeed removed most ‘isolation by distance’ effects over the total range of the populations. However, some populations were found to be more genetically similar and less aggressive against each other, thus forming ‘supercolonies’ extending over approximately 1000 km. These ‘supercolonies’ are likely to have a common recent history going back to the same introduction event. Our provisional estimates suggest that at least 3-5 independent introductions of L. neglectus into Europe have occurred. In contrast, clear ‘isolation by distance’ effects were found in both forms of L. turcicus, although worker aggression between different populations was generally lower in the lowland form of L. turcicus than in the highly aggressive highland form.
Current address of LVU and SC: University of Regensburg, Germany.
See more of Posters and Exhibits, Group B
See more of Poster Presentations
See more of The IUSSI 2006 Congress