All ants found within the genus Chalepoxenus are socially parasitic, raiding the nests of closely related Temnothorax species to capture their brood. The captured ants are raised as slaves of the Chalepoxenus ants to carry out the work of the colony (3) (4). Work includes rearing the slave-maker brood, foraging for food and protecting the nest from other invading insects (9).
Chalepoxenus muellerianus predominantly parasitises Temnothorax unifasciatus, although it also parasitises approximately 12 other species of Temnothorax, including T. tuberum and T. recedens (3) (4) (7). A colony will typically consist of a few dozen Chalepoxenus muellerianus individuals and from zero to several hundred host individuals (10).
Slave raids occur throughout the summer and involve several characteristic steps: scouting for host nests, recruitment of workers, fighting the host species and brood transport (11). The queen Chalepoxenus muellerianus selects only the host brood, and has no use for the other host ants (9). Young female Chalepoxenus muellerianus are responsible for gaining access to the host brood, and capture, destroy or evict any host ants using their stingers (4).
Chalepoxenus muellerianus colonies generally tend to exclusively parasitise one species of host, due to imprinting upon the odour of the host species during a very sensitive period of growth. This significantly affects the queens choice of host during colony foundation, and workers almost exclusively raid the nests of host species already working in the slave-makers nest (9) (10).