Distribution and genetic divergence of two parapatric sibling ant species in Central Europe

Abstract

The two sibling ant species Temnothorax nylanderi and Temnothorax crassispinus are widely distributed throughout deciduous forests in Europe. Their resemblance in morphology and similar ecological requirements suggest that they evolved from the same ancestral species in different glacial refugia and re-immigrated into Central Europe after the last ice age. Here, we show that the two species are parapatrically distributed in south-eastern Germany and hybridize along a narrow contact zone close to the continental divide. Phylogeographical data based on the mitochondrial genes cytochrome oxidase subunit I and cytochrome b suggest that the dominant haplotypes for T. nylanderi and T. crassispinus might have diverged already 1.5-2 Mya. Intraspecific variability is extremely low in both species, which might be explained by severe bottlenecks during rapid postglacial expansion into Central Europe.

Low genetic diversity in Polish populations of sibling ant species: Lasius niger (L.) and Lasius platythorax Seifert (Hymenoptera, Formicidae)

“…16S rRNA), 57% of L. niger haplotypes were identical and 60% of L. platythorax. In comparison, two other sibling ant species widespread in Europe: T. crassispinus and T. nylanderi, showed similar genetic divergence values in cox I haplotypes (2.4%) but no more than 40% haplotypes of both species were identical (Pusch et al, 2006). Moreover, when we complemented our analyses by adding the cox I and 16S rRNA sequences obtained from specimens of L. niger and L. platythorax from Austria (Steiner et al, 2004;Maruyama et al, 2008), we found that despite the long geographical distance, the most common Polish haplotypes of both species appeared to be identical to previously mentioned haplotypes deposited in GenBank.…”

“…Both sibling species are monogynous and monoandrous, what possibly leaves less opportunities for interspecific hybridization. However, in southern Germany, Temnothorax hybrid workers were frequently found among workers of pure-species T. nylanderi or T. crassispinus, despite obligate monogyny and monandry in both sibling species (Pusch et al, 2006). Although there are no detailed studies, the hybridization between L. niger and L. platythorax seems also probable and only detailed research based on more samples and a wider study area could shed more light on this topic.…”

“…The range of sequence divergences (Tables 2, 3) between L. niger and L. platythorax suggests that both species have been well separated though the time of interspecific diversification appears to be a rather recent. If we applied (after Pusch et al, 2006) the honey bee rate of mtDNA divergence, 2% per million years (Arias and Sheppard, 1996), these species would have diverged about 1 Mya.…”

“…However, there is a lack of data on geographic distribution of genetic diversity in L. platythorax and these concerning L. niger are scarce. The phylogeography of ants has only recently received attention (Goropashnaya et al, 2004;Pusch et al, 2006).…”

The influence of hybridization on colony structure in the ant species Temnothorax nylanderi and T. crassispinus

“…T. nylanderi occurs in Western Europe; its sibling, which is morphologically very similar, in Eastern Europe. Both species meet along a narrow contact zone close to the river Elbe in North-Eastern Germany (Seifert, 1995) and in the Franconian Jura in Southern Germany (Pusch et al, 2006). Previous morphological and genetic studies suggested occasional hybridization (Seifert 1995;Pusch et al, 2006).…”