Soil Organisms (Dec 2024)
Lasius frequens n.sp. – a sister species of the supercolonial pest ant Lasius neglectus showing a differing biology (Hymenoptera: Formicidae)
Abstract
A new sister species of the supercolonial invasive pest ant Lasius neglectus Van Loon et al., 1990 is described based on a broad sample from the Iran. It is named Lasius frequens n. sp. due to its abundance in that region. The strongest difference to the next similar species Lasius turcicus Santschi, 1921, L. neglectus Van Loon et al., 1990 and L. precursor Seifert, 2020 are distinctly longer scapes and terminal segments of maxillary palps. In order to disentangle the complicated situation within this species complex, species hypotheses were generated by exploratory and hypothesis-driven data analyses using numeric recordings of 16 morphological characters within a total of 255 nest samples with 782 worker individuals. The exploratory data analyses NC-part.kmeans and NC-NMDS.kmeans indicated the existence of five clusters. These classification hypotheses were confirmed through a controlling linear discriminant function (LDA) by 99.2 % in NC-part.kmeans and by 97.2 % in NC-NMDS.kmeans. As NC-clustering does not expose hybrid samples, the spatial distribution of the clusters was checked in the simple vectorial space by 2-dimensional plotting of cluster triples in a LDA. There was no indication for substantial interspecific hybridization in any triple plotted. The clusters 1, 2, 3 and 4 could be attributed to the four above-mentioned taxa by clear allocation of the type samples. A fifth, strongly separated, morphological cluster was not described as a separate species but was assumed to represent a setae morph of Lasius turcicus. Lasius frequens n. sp. differs from L. neglectus in having its main distribution in natural habitats but 28 % of the samples were also found in rural and urban habitats. Gynes of L. frequens n. sp. have about 160 % of the mesosoma volume of L. neglectus gynes which indicates strongly developed flight muscles. This morphological trait and the wide distribution over most different habitat types indicate that this species should perform, in contrast to L. neglectus, a normal nuptial flight with long-range flight-dispersal and independent single-queen colony foundation.
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