The wasp, which is about half an inch long, lives in small colonies of two to three dozen individuals in dark and dank conditions. It comes in two color types that mimic other wasp species living on the margins of its habitat, and males frequently make up half or more of a colony's population. O'Donnell studied 32 colonies of M. mastigorphorus, surveying the number of males present in each and collected detailed behavioral data on six of the colonies, tracking all individuals. Dominance behavior or aggressive social interactions occur at a high rate in many insect societies, according to O'Donnell. Up to now, this behavior was only known to be expressed by females, both by queens and workers, who usually perform most of the risky tasks and labor in insect colonies.
Queens dominate workers and workers dominate each other.
Males were at the bottom of the pecking order. Among the Costa Rican wasps, however, O'Donnell noted that males chased and lunged at females, sometimes biting or chewing on them, as well as chasing them off the nest. The females did not respond in kind or responded submissively to the male dominance. Instead workers and queens crouched, became immobile or fled the nest. Males also did not forage for food nor perform much labor for colonies, but they did consume a high percentage of the food brought to the nests by the females.