What is Tetramoriumsemilaeve André, 1883? (Hymenoptera, Formicidae)

Delineation of species of the Tetramoriumcaespitum complex (Hymenoptera, Formicidae) in Anatolia with a diagnosis of related species-complexes

The high level of morphological crypsis of the hyper-diverse Palearctic Tetramoriumcaespitum group have challenged taxonomists for decades. Within this group, Wagner et al. (2017) offered a multidisciplinary solution for the delimitation of ten European species of the Tetramoriumcaespitum complex. Anatolia, harboring a high level of endemism in ants, has never been subject of focus research within this genus. In this study, the Tetramoriumcaespitum complex diversity in Anatolia and the Caucasus region was investigated by examining 191 nest-samples using an in-depth integrative-taxonomic approach. Quantitative morphometric and microsatellite data of 505 and 133 workers, respectively, and genital-morphology data of 33 nests were collected. Unsupervised analyses provided independent species-hypotheses based on the morphological and molecular disciplines. Based on the final species-hypotheses, we confirm T.caespitum (Linnaeus, 1758), T.hungaricum Röszler, 1935, T.indocile Santschi, 1927, T.caucasicumWagner et al., 2017, T.impurum (Foerster, 1850), T.immigrans Santschi, 1927, and T.flavidulum Santschi, 1910 as valid species of the T.caespitum complex occurring in Anatolia. A lectotype of T.flavidulum was designated. The host of the temporary social-parasitic species Tetramoriumaspina Wagner et al., 2018 is T.caucasicum instead of T.immigrans - as it was suggested before. An identification key to species complexes of the T.caespitum group and to workers of the species of the T.caespitum complex in Anatolia is provided. Every cluster we identified could be linked to described species and the region's species-composition is similar to those of the Balkans and Central Europe.

Further records of social parasitic ants in Europe and review of the Bulgarian species

Background

Social parasitic ants exploit the colonies of other ant species, either permanently or temporarily. The permanent parasites are amongst the rarest species of ants, although their hosts may be very common. Due to their rarity and often restricted distribution range, most of them are listed as vulnerable. Filling in the gaps in geographical and host ranges will advance our understanding of the social parasitic lifestyle's origin and evolution.

New information

This study reports the first records of the slave-makers Myrmoxenusalgerianus (Cagniant, 1968) for Europe (Italy, Sicily) and M.ravouxi (André 1896) for Albania and the inquiline Anergatesatratulus (Schenck, 1852) for Malta (Gozo). We also report new localities of Camponotusuniversitatis Forel, 1890 for Albania and Myrmoxenusgordiagini Ruzsky, 1902, M.kraussei (Emery, 1915) and Anergatesatratulus for Bulgaria. Diversity, type of parasite-host relationships, host range, distribution and conservation of social parasitic ant species in Bulgaria are discussed. Although social parasitic ants are still understudied in Bulgaria, they represent 21% of the regional ant fauna.

Evolution of morphological crypsis in the Tetramorium caespitum ant species complex (Hymenoptera: Formicidae)

Cryptic species are morphologically very similar to each other. To what extent stasis or convergence causes crypsis and whether ecology influences the evolution of crypsis has remained unclear. The Tetramorium caespitum complex is one of the most intricate examples of cryptic species in ants. Here, we test three hypotheses concerning the evolution of its crypsis: H1: The complex is monophyletic. H2: Morphology resulted from evolutionary stasis. H3: Ecology and morphology evolved concertedly. We confirmed (H1) monophyly of the complex; (H2) a positive relation between morphological and phylogenetic distances, which indicates a very slow loss of similarity over time and thus stasis; and (H3) a positive relation between only one morphological character and a proxy of the ecological niche, which indicates concerted evolution of these two characters, as well as a negative relation between p-values of correct species identification and altitude, which suggests that species occurring in higher altitudes are more cryptic. Our data suggest that species-specific morphological adaptations to the ecological niche are exceptions in the complex, and we consider the worker morphology in this complex as an adaptive solution for various environments.