Heriades

Distinguished from other Osmiini genera (Hoplitis, Ashmeadiella) by combination of small size, typically black coloration, and abdominal pilosity patterns. Resin use for nest cell partitions is characteristic but not exclusive. Male genitalia morphology provides definitive identification at species level. In the Americas, subgenus Neotrypetes is the only Heriades subgenus present.

Small bees, usually black in coloration. Many species have hairy patches on the abdomen, referenced in the genus name which derives from Greek for 'wool'. Sexual dimorphism is present: males of some species exhibit enlarged heads (e.g., 'large-headed resin bee' for H. truncorum).

Nests in pre-existing cavities in dead wood, including beetle borings and hollow twigs; occasionally uses pine cones. In urban areas, occupies artificial bee blocks and bee hotels. Requires access to resin sources for nest construction and appropriate cavity dimensions (typically smaller diameter tunnels).

Cosmopolitan distribution with more than 130 species worldwide. In the Western Hemisphere: southern Canada through Panama and the Greater Antilles, with extension to northern Colombia (first South American record). North America: approximately 25 species, with highest diversity west of the Rocky Mountains; only three species native east of the Rockies. European species (e.g., H. truncorum) introduced to eastern United States.

Heriades truncorum is oligolectic on Asteraceae. Other species' pollen preferences are poorly documented; some flexibility in host plant use has been observed in urban populations of H. truncorum, including non-native and non-Asteraceae pollen collection when primary hosts are limited.

Solitary lifecycle with no worker caste. Females construct linear series of brood cells in pre-existing cavities, each provisioned with pollen-nectar mixture ('bee bread') and sealed with resin partitions. Typically leaves one empty cell at nest entrance before final resin plug, possibly as parasite deterrent. Developmental stages: egg, larva, pupa, adult. Voltinism varies by species and climate.

Nesting: females use abdominal scopa to transport pollen. Nest construction involves resin collection and application for cell partitions and entrance plugs. Mating: males of H. truncorum perform courtship displays including wing fanning and sideways rocking motions; these mechanical signals, combined with chemical cues from female cuticular hydrocarbons, mediate mate recognition and female choice. Female mate choice is density-dependent, with size-based selection occurring when multiple males are present.

Pollinator, particularly of Asteraceae where documented. Contributes to native bee diversity in agricultural and urban landscapes. Serves as host for parasitic wasps including Sapygidae (Sapygids), which lay eggs in provisioned nests.

Used as research model for studying bee sexual communication, pesticide sublethal effects (particularly flupyradifurone), and urban bee ecology. Occupies artificial bee blocks, making it observable for citizen science and pollinator conservation education. Wildflower strips benefit populations and may provide crop pollination services in agricultural systems.

• HoplitisBoth in tribe Osmiini, share wood-cavity nesting and resin use; distinguished by Hoplitis typically having more robust body form and different abdominal scopa structure
• AshmeadiellaBoth in tribe Osmiini with similar nesting habits; Ashmeadiella species often have more restricted distributions and different facial markings
• OsmiaBoth Megachilidae with cavity-nesting habits; Osmia typically uses mud or chewed leaf material rather than resin for cell partitions, and often shows metallic coloration absent in Heriades

• solitary bee
• resin bee
• cavity nester
• pollinator
• Osmiini
• Megachilidae
• model organism

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Bug Eric: More Drama at the Bee Block
• Wildflower Strips Bring Farmers Extra Money While Helping Native Bees
• A Nest of Heriades variolosus (Cress.); (Hymenoptera: Megachilidae)
• Taxonomic notes on American Heriades Spinola, 1808 and Leioproctus Smith, 1853 (Hymenoptera: Megachilidae, Colletidae)
• Chemical and Mechanical Signals Trigger Courtship in the Wild Large-Headed Resin Bee Heriades truncorum
• Figure 2: Species distribution maps of tunnel nesting bees in the genera Heriades, Hylaeus, Osmia and Stelis found from the Minnesota Bee Atlas nest traps
• Mating behaviour of the large-head resin bee Heriades truncorum (Megachilidae: Osminii) suggests female plastic strategy in selection of a mating partner and male quality assessment
• Neotropical bees of the genus Heriades Spinola, 1808 (Hymenoptera: Megachilidae: Osmiini) with description of nine new species
• Exposure to sublethal concentration of flupyradifurone alters sexual behavior and cuticular hydrocarbon profile in Heriades truncorum, an oligolectic solitary bee
• DNA metabarcoding reveals unexpected diet breadth of the specialist large‐headed resin bee ( Heriades truncorum ) in urbanised areas across Germany