What Bug Is That? The guide to Australian insect families.

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The flat bugs (or bark bugs) are primarily mycetophagous (fungus feeders) that exhibit cryptic habits and colouration. The family is found world wide, predominantly in tropical areas.

The Aradidae are usually found under the bark of decaying trees, logs, debris or in leaf litter in moist forests and rainforests. Occasionally they inhabit the nests of rodents, termites and birds. A few species are sap feeders, but the majority use their extremely long stylets to follow fungal hyphae through the cracks and crevices of decaying material. The aradid maxillary and mandibular stylets are unusual within the Heteroptera (except for the Termitaphididae) being coiled within the head and extruded through contraction of sacs within the head.

Winglessness (aptery) or wing reduction (brachyptery) is common within the Aradidae and close to half the Australian aradid fauna is wingless. These characters, combined with their flat shape and short legs, allows aradids to inhabit cramped and confined spaces where fungus is common. However, aptery and brachyptery are highly variable within species and between the sexes. Some species have both winged and wingless morphs of the same sex and some have winged morphs of one sex and wingless morphs of the other.


Australia possesses nearly a tenth of the world aradid fauna, and all 8 recognised subfamilies are found here. The majority of the Australian species belong to the subfamily Mezirinae with 92 species distributed in 23 genera. The remaining 50 species are shared between 7 subfamilies (Aneurinae, Aradinae, Calisinae, Carventinae, Chinamyersiinae, Isoderminae and Prosympiestinae).

  • Araridae (Heteroptera)

  • flat or bark bug