As with other members of the family, this insect lives its whole life cycle as an inquiline within ants' nests, feeding on the developing ant larvae. M. acervorum appears to show a preference for ants of the genus Lasius. This specialized way of life has led this insect and its relatives to evolve many morphological differences to other orthopterans including complete absence of wings (as they never leave their host nest) and hearing organs (as they no longer use stridulation) and much reduced eyesight, as well as their very small size.
These tiny insects are dark brown with paler bands and prominent cerci which serve as their primary sensory organs. Adults are found throughout the year and take up to two years to reach adulthood from hatching. In some populations, males are very rare, the females reproducing parthenogenetically.