A new taxonomic status for Iberoformica (Hymenoptera, Formicidae) based on the use of molecular markers

Abstract

The subgeneric subdivision of the genus Formica is still open. In this article, we make a phylogenetic study on several species of the genus Formica and of its closely related genera, Polyergus and Proformica, using sequences of nuclear satellite DNA (stDNA) and the mitochondrial rrnL as molecular markers. Our goal was to shed light on their phylogenetic relationships and particularly on the systematic position of F. subrufa. This species was first included in the subgenus Serviformica, but afterwards a new subgenus (Iberoformica) was established to include only this species. The results show that a stDNA family previously reported in Formica species, with a repetitive unit 129 bp long, is also found in Polyergus rufescens and P. samurai but not in Proformica longiseta. This is the first case of presence of a stDNA family in two different ant genera. In F. subrufa, this stDNA is very divergent relative to those isolated in the remaining Formica species and in the genus Polyergus. The Bayesian analysis of mitochondrial rrnL sequences shows three highly supported groups: F. subrufa, the remaining Formica species studied, and the genus Polyergus, suggesting that parasites (Polyergus species) and hosts (Formica species) are closely related but not sibling species. The combined analysis of nuclear stDNA sequences and mitochondrial rrnL showed their phylogenetic congruence despite their distinct evolutionary dynamics. This analysis did not discriminate between the remaining Formica species that were not grouped according to the subgeneric classification. According to these results, it can no longer be assumed that F. subrufa belongs to the subgenus Serviformica or of the fusca species group. This differentiation was also supported by previous studies based on the morphological characters, molecular and cytogenetic data. Therefore, taking into consideration these arguments and others explained in detail in this article, we propose that the taxon Iberoformica, formerly synonymized subgenus, be raised to a genus status. This genus would be monotypic and only composed, up to the moment, by Iberoformica subrufa (= F. subrufa Roger, 1859).

Phylogenetic relationships between the slave-making antsRossomyrmexand theirProformicahosts in relation to other genera of the ant tribe Formicini (Hymenoptera: Formicidae)

“…Muñoz‐López et al. () found similar results for the slave‐making ants Polyergus and its host genus Formica , which agrees with the conclusion of Huang and Dornhaus () that slave‐making ants usually parasitize hosts from the same tribe and a close genus. Furthermore, our results stress the importance of including the genus Rossomyrmex in any phylogeny of Cataglyphis because its absence or presence influences the monophyletic status of the latter as well as the relationships among the different species groups.…”

“…Ants of the tribe Formicini (subfamily Formicinae) are the most conspicuous element of the Holarctic myrmecofauna (Dlussky, ) and include eight extant genera: Alloformica , Bajcaridris , Cataglyphis , Formica , Iberoformica , Polyergus , Proformica, and Rossomyrmex (Agosti, ; Muñoz‐López et al., ; Ward, Blaimer, & Fisher, ). Within this tribe, there are two genera of obligate slave makers: Polyergus and Rossomyrmex .…”

“…Within this tribe, there are two genera of obligate slave makers: Polyergus and Rossomyrmex . The first one is the most studied, with 14 known species (Trager, ) parasitizing ants of the genus Formica and with several phylogenetic studies supporting Emery's rule in its loose version (e.g., Chen, Zhou, Ye, & Lu, ; Hasegawa, Tinaut, & Ruano, ; Muñoz‐López et al., ; Ward et al., ). In contrast, Rossomyrmex consists of only four species, which parasitize species of the ant genus Proformica (Ruano, Sanllorente, Lenoir, & Tinaut, ): P. epinotalis Kuznetsov‐Ugamsky, 1927 parasitized by R. proformicarum Arnoldi, 1928 in the North shore of the Caspian Sea (Russia); P. cf epinotalis and R. quandratinodum Xia and Zheng, 1995 are found between China and Kazakhstan; P. korbi Emery, 1909 and R. anatolicus Tinaut, in the plains of Anatolia (Turkey); and P. longiseta Collingwood, 1978, with a patchy distribution in high mountains of southeastern Spain parasitized in three of them by R. minuchae Tinaut, .…”

Differentiating Iberoformica and Formica (Serviformica) with Description of the Sexual Castes of Formica (Serviformica) gerardi Bondroit, 1917 stat. rev.

“…In a later study previous results were confirmed, and Iberoformica was raised to a genus status only composed by I. subrufa. In the present study a phylogenetic study was carried out on several species of the genus Formica and of its outgroup genera, Polyergus and Proformica, using sequences of nuclear satellite DNA and the mitochondrial 16S rRNA as molecular markers (Muñoz-López & al. 2012).…”