Tricrania sanguinipennis

Distinguished from other Tricrania species by adult coloration and geographic range; T. stansburyi is the only other congeneric species in North America, and the two have been subject to taxonomic revision. The vestigial wings and flightless condition separate it from most other meloid beetles in its range. DNA barcoding (565-bp COI fragment) is available for definitive identification. First instar larvae (triungulins) are sleek, streamlined, and highly mobile—distinctly different from later instars.

Open areas with sandy or loose soil where host bees nest. Often found in lawns, parks, and forest edges where Colletes bees aggregate. Adults are encountered on the ground surface, crawling rapidly and digging where host presence is detected.

Eastern North America from Saskatchewan and southern Canada south to extreme northern Florida. Western limit approximately Kansas. Records from Ontario, Québec, Vermont, and throughout the eastern United States.

Adults active from late February through March in warmer years, typically emerging early spring. Phenology tied to host bee emergence. Overwintering occurs as adults encased in larval exuviae within host nest cells.

• Colletes inaequalis - parasitoidUnequal Cellophane Bee; primary host. Triungulin larvae attach to male bees, transfer to females during mating, and are carried to underground nest cells.
• Colletes spp. - parasitoidOther cellophane bees in dense nesting aggregations; host specificity centered on genus Colletes.

Hypermetamorphic with six larval instars. First instar (triungulin) is mobile, attaches to host bees, and enters nest cells. Immediately consumes host egg or larva, then molts to second instar. Instars 2–6 are sedentary, boat-shaped, and feed on pollen/nectar stores. Instars 4–5 retain exuviae (like nested balloons), shrinking to fit inside. Pupa forms within retained exuviae. Adult overwinters in host cell, emerging following spring.

Adults crawl rapidly over soil, digging periodically to detect hosts. Flightless; all locomotion by walking. Females deposit hundreds to over one thousand eggs. Triungulin larvae actively seek and board male bees, transferring to females during mating. Cannibalism occurs when multiple larvae invade single host cell.

Parasitoid of solitary bees; population impacts on hosts appear limited despite high reproductive output. Serves as case study for hypermetamorphosis and host manipulation in insects. Potential indicator of healthy Colletes bee populations and associated floral resources.

Of interest to entomologists studying parasitoid-host relationships and hypermetamorphosis. No significant agricultural or medical importance. Can be observed in urban and suburban settings where host bees nest in lawns. Climate change effects on host plant phenology (Eastern Redbud, maple flowering) may indirectly threaten populations.

• Tricrania stansburyiOnly other species in genus Tricrania; historically confused but now distinguished through taxonomic revision. T. stansburyi has different distribution and host associations.
• Epicauta spp.Other common North American blister beetles; distinguished by functional wings, different coloration patterns, and plant-feeding (not parasitoid) life history.
• Meloe spp.Oil beetles share hypermetamorphic life cycle but have different host associations (typically bees in other families) and adult morphology; often larger with different body proportions.

• hypermetamorphosis
• triungulin
• parasitoid
• flightless
• Colletes
• cellophane bees
• early spring
• sandy soils

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Meloidae Holdings | Entomology Research Museum
• Bug Eric: The Beetle and the Bee
• The blister beetle Tricrania sanguinipennis—biology, descriptions of different stages, and systematic relationship
• Revision of the nearctic blister beetle genus Tricrania LeConte, 1860 (Coleoptera: Meloidae: Nemognathinae)