Acrotrichini

Acrotrichini is distinguished from other Ptiliidae tribes by the combination of: 3-segmented antennal club (vs. 2-segmented in some related groups); specific wing venation patterns with characteristic reduction of longitudinal veins; and particular arrangement of setae on the elytral surface. Separation from the tribe Ptiliini requires examination of male genitalia and detailed wing venation; Acrotrichini generally shows more reduced wing venation and different spermathecal morphology in females. Identification to genus level relies on tarsal formula, presence or absence of elytral striae, and details of the prosternal process.

Decaying organic matter including rotting wood, leaf litter, compost, fungal fruiting bodies, and manure. Strongly associated with moist microhabitats where fungal hyphae and spore-bearing substrates are abundant. Often found in ant nests (myrmecophily) and termite colonies. Requires high humidity to prevent desiccation due to small body size and high surface area to volume ratio.

Cosmopolitan distribution with records from North America, Europe, Asia, Africa, Australia, and New Zealand. Most diverse in temperate and subtropical regions. Widespread but often undercollected due to minute size.

Adults active year-round in suitable microhabitats; peak abundance typically coincides with periods of high humidity and abundant fungal substrate (spring and autumn in temperate regions). No true dormancy period; continuous breeding in stable environments.

Mycophagous; feeds primarily on fungal spores and hyphae. Some species may consume other minute organic particles in decaying substrates.

Eggs deposited in fungal substrate or decaying organic matter. Larvae are campodeiform (elongate, active) and feed on fungal material. Pupation occurs within substrate. Development rapid due to small size; multiple generations per year possible under favorable conditions. Complete metamorphosis (holometabolous).

Strong thigmotactic response (preference for tight spaces); actively seeks crevices in substrate. Flight capability retained despite small size, using specialized wing folding and fringe-assisted flight mechanics. Aggregates in suitable microhabitats. Some species exhibit phoretic behavior, dispersing via larger insects.

Primary decomposer facilitating fungal spore dispersal and nutrient cycling in decaying organic matter. Serves as prey for minute predators including mites, small spiders, and predatory insects in soil and litter communities. Contributes to fungal community dynamics through spore consumption and gut-mediated dispersal.

No direct economic importance. Occasionally found in compost and agricultural settings where organic decomposition occurs. Indicator of mature, stable decay communities in ecological assessments. Rarely encountered by non-specialists due to size.

• PtiliiniShares family Ptiliidae and subfamily Ptiliinae; distinguished by 2-segmented antennal club, different wing venation, and distinct male genitalia structure
• NanoselliniAnother tribe of Ptiliidae with minute species; separated by body form, wing structure, and habitat preferences (more strongly associated with polypore fungi)
• CephaloplectinaeSubfamily of Ptiliidae with reduced elytra; distinguished by exposed abdominal segments and different wing morphology

• beetle
• featherwing beetle
• minute beetle
• mycophagous
• decomposer
• Ptiliidae

• BugGuide
• iNaturalist taxon
• Catalogue of Life