Woodroach

• The young are born without symbionts and must acquire them by ingesting anal secretions from their parents, which obliges the family to stay together for years.
• Its gut symbionts are almost identical to those of termites, and this cockroach is their closest living relative: termites are, in evolutionary terms, social cockroaches.
• A family can live together in the same gallery for more than three years, a degree of parental care very rare among non-social insects.
• It is the key to understanding the origin of termites. Molecular studies have shown that termites are eusocial cockroaches, and that this genus is their sister group: it is the best living model of the termites' ancestor.
• It lives as a family. The pair digs galleries in a rotten log and raises its offspring for years, with prolonged biparental care — something exceptional among cockroaches and exactly what is considered the starting point of termite eusociality.
• It cannot digest wood on its own: it depends on symbiotic flagellates in its hindgut, the same lineages found in the lower termites.
• And those symbionts are inherited in a very particular way: by proctodeal trophallaxis, that is, the parents transfer fluid from the hindgut to the mouths of their young. Without that contact, the offspring could not digest wood.
• The full microbiota is not established until the third nymphal instar, when the young achieve independence in feeding.
• It is wingless: neither the male nor the female has wings.
• Its life cycle is extremely slow for a cockroach: it takes more than five years to complete, and the adults live for several years.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat & environment

Fallen rotting logs of the humid forests of the Appalachians

Sources consulted: Nalepa (2020), Encyclopedia of Social Insects; Ohkuma et al. (2009), Proceedings of the Royal Society B; Berlanga et al. (2016), PLOS ONE