Parasitic flat bark beetles

Definition

A family of beetles (Passandridae) characterized by their dorsoventrally flattened bodies and obligate parasitic or inquilinous lifestyle within the galleries of wood-boring beetles, particularly longhorn beetles (Cerambycidae) and metallic wood-boring beetles (Buprestidae). Adults and larvae inhabit tunnels in dead or dying wood, feeding on host larvae or exploiting the microhabitat resources. The family comprises approximately 100 species in 9 genera, distributed primarily in tropical and subtropical forests. Their flattened morphology—an adaptation for navigating tight spaces in wood galleries—distinguishes them from most other cucujoid beetles.

Etymology

From Latin 'parasitus' (one who eats at another's table) + English 'flat bark beetles', referring to their compressed body form and habit of living under bark; Passandridae from genus Passandra (Greek 'pas' all + 'andros' of man, of uncertain application) + '-idae' family suffix

Example

Passandra elongatula, a widespread Palearctic species, develops exclusively in the galleries of cerambycid beetles in decaying hardwoods, with larvae preying on host eggs and young larvae.

Synonyms

• Passandridae

Related Terms

• Cucujoidea
• inquiline
• bark beetle
• Cerambycidae
• wood-boring beetle
• myrmecophile
• subcortical habitat

Usage Notes

The common name emphasizes the parasitic habit, but many species are more accurately described as inquilines (guests that share the host's nest without direct harm) or facultative predators rather than strict parasites. The family was historically classified in Cucujidae or treated as a subfamily; molecular phylogenetics confirmed Passandridae as a distinct family within Cucujoidea. Specimens are rarely collected by standard surface sampling methods and require specialized extraction from wood galleries or rearing from infested logs.