Tetratoma

Members of Tetratoma are small beetles, generally 3–5 mm in length. They can be distinguished from related genera in Tetratomidae by the structure of the antennae, which have a distinct club with three enlarged terminal segments. The body is typically elongate-oval and somewhat flattened. Identification to species level requires examination of genitalia and detailed microsculpture of the elytra.

Tetratoma species inhabit forested environments where they are found in association with fruiting bodies of polypore fungi (Basidiomycota), particularly on decaying wood of hardwood trees. They are typically collected from the undersides of bracket fungi or within the porous hymenial surface of polypores.

The genus is recorded from northern Europe (Denmark, Norway, Sweden) and has a broader Palearctic distribution. Specific species ranges vary, with some restricted to boreal or montane forests.

Adult activity peaks during summer months when host fungi are actively fruiting. Some species may be found from late spring through early autumn depending on local climate and fungal phenology.

Larvae and adults feed on the mycelium and spore-producing tissues of polypore fungi. The precise nutritional relationship—whether primarily mycophagous or involving fungal decay products—has not been fully characterized for most species.

• Polyporaceae - food sourcebracket fungi on decaying wood

Larval development occurs within the fruiting bodies of host fungi. The complete life cycle from egg to adult likely spans one year, though specific timing varies by species and latitude. Pupation occurs within the fungal substrate or adjacent wood.

Adults are cryptic and remain concealed within the porous surface of bracket fungi during daylight hours. They are capable of flight and have been observed dispersing to new fungal substrates. When disturbed, they may feign death or retreat deeper into fungal pores.

Tetratoma contributes to nutrient cycling in forest ecosystems through consumption and processing of fungal biomass. The genus may serve as prey for small invertebrates within the microhabitat of decaying wood communities.

No direct economic importance. The genus is occasionally encountered by mycologists and entomologists during fungal surveys. Some species may serve as indicators of old-growth forest conditions due to specific host requirements.

• Tetratomidae (other genera)Other genera in the same family (e.g., Euryoma, Hallomenus) share similar size and habitat but differ in antennal structure and body proportions
• MycetophagidaeHairy fungus beetles occupy similar niches but have more elongate bodies and different antennal club structure

• mycophagous
• saproxylic
• polypore-associated
• cryptic
• old-growth indicator

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life