Bolboceratinae

Bolboceratinae are distinguished from other Geotrupidae by a combination of characters including: clypeus not or only weakly emarginate; antennae with 9-11 segments; tarsi with reduced number of segments (3-3-3 or 4-4-4 in most); and often with pronounced sexual dimorphism in cephalic and pronotal armature. Males frequently possess horns, tubercles, or other projections on the head and pronotum that are reduced or absent in females. The scutellum is usually visible and triangular. Body form ranges from compact and convex to more elongate and cylindrical.

Species occupy diverse terrestrial habitats including forests, woodlands, grasslands, and semi-arid regions. Australian species have been collected from eucalypt woodlands and forests. Philippine species are forest-dwelling, with specimens collected using flight intercept traps near streams at elevations of 50–995 m. Some Western Australian species occur in sandy soils.

Disjunct global distribution including: Australia (Western Australia and widespread), South America (Chile, Brazil, Ecuador, Peru, Argentina), southern Africa, Europe (central and eastern), and Asia (Philippines, Indochina, Sumatra, Borneo). The genus Bolbelasmus occurs across Europe and Asia; Bolborhinum is restricted to southern South America; Bolbochromus occurs in the Philippines and broader Oriental region; Australian genera include Blackburnium, Blackbolbus, Bolborhachium, and Bolboleaus.

Adults of some Western Australian species feed on hypogeous mycorrhizal fungi (truffles). Blackbolbus frontalis and B. fucinus have been documented feeding on sporocarps of Amarrendia, Hysterangium, and Scleroderma. Some Blackburnium, Bolboleaus, and Bolborhachium species ingest glomeralean mycelium and spores with soil. Diet of other regional lineages remains undocumented.

Some Australian species exhibit egg gigantism, with females producing single eggs weighing up to 56% of maternal body mass. In at least Blackburnium reichei, eggs are deposited in small, bare earthen cells without food provision, and development to adulthood occurs without larval feeding. Larvae of some species have globose body form, vestigial appendages, and complete immobility. Immature stages described for relatively few species; a table of literature sources describing immature stages has been compiled.

Adults are nocturnal and have been collected at lights. Western Australian species construct burrows in soil, with some species found in burrows containing truffles. Flight intercept traps have been used successfully for collecting forest-dwelling species in the Philippines.

Potential dispersal agents for mycorrhizal fungal spores based on documented ingestion of hypogeous sporocarps and glomeralean mycelium. The extent of their contribution to fungal dispersal remains limited.

• GeotrupinaeBoth are subfamilies of Geotrupidae; Geotrupinae typically have a more strongly emarginate clypeus and different tarsal formula, and lack the pronounced cephalic armature seen in many Bolboceratinae.
• TaurocerastinaeAnother geotrupid subfamily with earth-boring habits; distinguished by different antennal club structure and geographic restriction to South America.

• Coleoptera
• Scarabaeoidea
• Geotrupidae
• earth-boring beetles
• mycophagy
• egg gigantism
• Australia
• South America
• fossorial

• BugGuide
• Wikipedia
• iNaturalist taxon
• Catalogue of Life
• A revision of the southern South American genus Bolborhinum Boucomont (Coleoptera: Geotrupidae: Bolboceratinae)
• Review of the genus Bolbochromus (Coleoptera, Scarabaeoidea, Geotrupidae, Bolboceratinae) in the Philippines
• A new species of Athyreus MacLeay, 1819 (Coleoptera: Geotrupidae: Bolboceratinae: Athyreini) from northeastern Brazil
• A systematic review of the genus Bolbelasmus Boucomont (Coleoptera, Geotrupidae, Bolboceratinae) from Indochina and surrounding areas
• Records of hypogeous mycorrhizal fungi in the diet of some Western Australian bolboceratine beetles (Coleoptera: Geotrupidae, Bolboceratinae)
• Egg gigantism in some Australian earth‐borer beetles (Coleoptera: Geotrupidae: Bolboceratinae) and its apparent association with reduction or elimination of larval feeding
• Results of ongoing mapping of Bolbelasmus unicornis (Schrank, 1789) (Coleoptera: Geotrupidae: Bolboceratinae): the second addendum to the biogeographical study from 2022, with a literature review and new records of B. keithi Miessen & Trichas, 2011 and B. nireus (Reitter, 1895)
• Aequatobolbus, a new South American genus of Bolboceratinae (Coleoptera: Scarabaeoidea: Bolboceratidae) from Ecuador.