[4] Despite this apparent difference in habitat (extended plains versus high mountains), the abiotic conditions are quite similar and are consistent with a typical arid steppe.

Rossomyrmex is the only reported slave-maker that exclusively uses adult transport and single recruitment chain instead of pheromones during raids.

This condition imposes that Rossomyrmex raids appear as less efficient than those carried out with pheromones; this, together with the usually flee behavior of the Proformica hosts permits the survival of several attacked nests.

[11] In contrast, females are strictly monandrous although there are some reported cases of multiply mated queens.

After taking over the host nest by killing the resident queens, the size of this gland decreases.

[13] This strategy to invade a host nest contrasts with other extended strategy consisting in newly mated queens embarking in a slave raid with workers, which would facilitate the penetration of the host nest immersed in chaos.