Rossomyrmex, the Slave-Maker Ants from the Arid Steppe Environments

Abstract

The host-parasite genera Proformica-Rossomyrmex present four pairs of species with a very wide range of distribution from China to Southeastern Spain, from huge extended plains to the top of high mountains. Here we review (1) the published data on these pairs in comparison to other slave-makers; (2) the different dispersal ability in hosts and parasites inferred from genetics (chance of migration conditions the evolutionary potential of the species); (3) the evolutionary potential of host and parasite determining the coevolutionary process in each host-parasite system that we treat to define using cuticular chemical data. We find a lower evolutionary potential in parasites than in hosts in fragmented populations, where selective pressures give advantage to a limited female parasite migration due to uncertainty of locating a host nest. A similar evolutionary potential is detected for hosts and parasites when the finding of host nests is likely (i.e., in continuous and extended populations). Moreover, some level of local adaptation at CHC profiles between host and parasite exists independently of the kind of geographic distribution and the ability of dispersal of the different populations. Similarity at CHC profiles appears to be a trait imposed by natural selection for the interaction between hosts and slave-makers.

Co‐evolutionary Dynamics of a Social Parasite–host Interaction Model: Obligate Versus Facultative Social Parasitism

“…They have been suggested to represent an intermediate parasitic stage, between those species without predominant brood raiding, and obligate slave‐making species (Topoff and Zimmerli [], Ruano et al. []). 2.When the death rate d of the parasite is independent of its trait value, Corollary implies that the trait component of the host‐only equilibrium can be an ESS when the parasite is obligate; and the trait component of the facultative parasite‐only equilibrium can also be an ESS. …”

“…These species display the ability to vary behaviorally between reliance on parasitism of other ants, and producing their own worker offspring. They have been suggested to represent an intermediate parasitic stage, between those species without predominant brood raiding, and obligate slave-making species (Topoff and Zimmerli [1991], Ruano et al [2013] -7); (ii) the variances of the proposed trait functions, i.e., σ K 1 , σ K 2 , and σ d , play essential roles in guaranteeing the trait component (0, 0) of the local stable coexistence equilibrium (x * 1 , x * 2 , 0, 0) being an ESS; (iii) when the parasite death rate d is large, the host can have ESS that drive the parasite extinct globally; and (iv) Large variances of the parasite carrying capacity σ K 2 and of the parasitism efficiency σ a are required to make sure of the trait component (0, 0) of (x * 1 , x * 2 , 0, 0) being an ESS. In addition, we have following interesting results: (a) It is possible to have locally stable coexistence equilibrium (x * 1 , x * 2 , u * 1 , u * 2 ) with u * 1 , u * 2 > 0 (see Proposition (4.1)) but the trait components of these equilibria may not be ESS.…”

“…Such a case could be applied to slave‐making ants, which can be either obligate social parasites, depending on enslaved hosts ants throughout their whole lives (Topoff and Zimmerli [], Ruano et al. []) or alternatively facultative slave‐makers. Facultative slave‐making ants, like those in the Formica sanguinea complex, may engage in slave making, but individual colonies are able to revert to producing their own workers if parasitized workers are removed (Topoff and Zimmerli []).…”

Interspecific Eavesdropping on Ant Chemical Communication

“…Mycocepurus castrator inquiline parasites experimentally placed near a host nest quickly entered the nest signifying that they are able to sense their host (Rabeling and Bacci, 2010). Dulotic slave-making species and Megalomyrmex agro-predator raiders also find host colonies as young queens or later as scout workers (Boudinot et al, 2013;Ruano et al, 2013). This suggests they are using host-derived chemical cues to find the host nest and brood ( Table 1).…”

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

“…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, . In addition, it has been recently found that P. nasuta Nylander, 1856 can be parasitized by R. minuchae (Azcárate et al., ).…”