Intruders in the Nest: Interaction of Attaphila paucisetosa (Blattodea: Blaberoidea) with Atta cephalotes Workers (Hymenoptera: Formicidae)

The small cockroach Attaphila paucisetosa, a myrmecophilic species, was recently reported in nests of the leafcutter ant Atta cephalotes in Southwestern Colombia. We carried out both behavioral bioassays and field observations to learn more about this cockroach-myrmecophilous association. When we excavated the nests of A. cephalotes did not found cockroaches out of the anthills. We collected all lifecycle stages of At. paucisetosa (ootheca, nymphs, male and female adults) inside of fungus chambers of the leafcutter ants' nests. In lab, we observed that At. paucisetosa recognized artificial trails of A. cephalotes as well as worker ants. Our results show that At. paucisetosa is recognized by A. cephalotes workers as an intruder, triggering aggressive behavior, but the aggressiveness reduced in the presence of the ants' fungus. Also, the cockroach may use foraging trails and its attachment abilities to ride on foraging ant, facilitating the entrance to the stablished colonies, but the cockroach must take risks (from being mutilated or killed) since it is recognized as an intruder, so it takes advantage of its small size to try to find refuge in the fungus crevices, taking recognition profile hydrocarbons from the ants.

Automated summary

The study found that the small cockroach Attaphila paucisetosa parasitizes in nests of the leafcutter ant Atta cephalotes, recognizes the odor of the ant colony, and uses its small size and attachment abilities to avoid being killed by the ants.