Acmaeodera tubulus

Distinguished from similar eastern species Acmaeodera neglecta by smaller, finer punctures on the pronotum, brighter surface sheen, and yellow spots on elytra remaining separate rather than coalescing into irregular 'C'-shaped markings. A. neglecta is also duller and primarily restricted to glade habitats in the south-central U.S. Distinguished from A. ornata by smaller size (A. ornata is 8–11 mm), lack of triangular depression on pronotum, bronzy rather than bluish elytral sheen, and fewer, larger yellow spots. Distinguished from southwestern congeners in the tubulus-group (A. carlota, A. ornatoides, etc.) by geographic range and specific combinations of punctation density, elytral interval texture, and setal characteristics.

Small beetle, 5–7 mm in length. Body black with distinct bronzy sheen. Elytra bear eight small yellow spots arranged in two longitudinal rows of four spots each, though spot number may vary. Pronotum finely punctate. Elytral intervals subrugose and slightly irregular. Prosternal margin nearly straight, not retracted from sides (diagnostic for 'Truncatae' group). Elytra fused and do not separate during flight, giving a bee-like profile in flight similar to small halictid bees. Body covered with short, stiff setae.

Occurs in diverse habitats across eastern North America, including deciduous forests, forest edges, open woodlands, and areas with abundant flowering vegetation. Adults frequently found on flowers in sunny conditions. Larval habitat consists of dead twigs and small branches of various hardwood trees.

Eastern North America, widespread and common across the eastern United States. Records extend from Ontario, Canada southward throughout the eastern U.S. Not known from the southwestern U.S. or Mexico, where related species in the tubulus-group occur.

Active in spring and early summer. Adults observed on flowers from late spring through summer, with peak activity during flowering periods of host plants.

Adults feed on pollen and petals of a wide variety of flowers, including eastern beebalm (Monarda bradburiana), Krigia species, and Rosa carolina. Larvae are wood borers in dead twigs and small branches of various hardwood trees.

• Monarda bradburiana - adult food sourcepollen and petal feeding
• Krigia sp. - adult food sourceobserved on flowers at higher elevations
• Rosa carolina - adult food sourcephotographed on flowers
• Crataegus viridis - larval hostreared from dead branches of green hawthorn
• Carya spp. - larval hostreared from several hickory species
• Celtis occidentalis - larval hostreared from hackberry
• Gleditsia triacanthos - larval hostreared from honey locust
• Juglans nigra - larval hostreared from walnut
• Ostrya virginiana - larval hostreared from eastern hophornbeam
• Salix sp. - larval hostreared from willow
• Ulmus rubra - larval hostreared from slippery elm

Complete metamorphosis. Larvae develop as wood borers in dead twigs and small branches of hardwood trees, taking one or more years to develop. Adults emerge in spring and feed on flower pollen and petals. Specific timing of egg-laying and pupation not documented.

Adults are active diurnal flower visitors, frequently observed feeding on pollen and petals. In flight, adults resemble small bees due to fused elytra that do not separate during flight, creating a profile similar to halictid bees. Adults are often found in sunny conditions on flowers. When disturbed, adults may drop from flowers or fly short distances.

Adults function as pollinators through pollen feeding and transport. Larvae contribute to nutrient cycling by boring in dead hardwood branches. The species serves as a food source for various insectivores. As a common and widespread species, it contributes to the guild of flower-visiting beetles in eastern North American ecosystems.

Occasionally encountered by entomologists and naturalists during field work. No significant economic importance; larvae do not attack living timber or structural wood. Sometimes photographed by macro photographers due to accessible flower-visiting behavior. Used as a reference species for understanding the tubulus-species group within Acmaeodera.

• Acmaeodera neglectaSimilar size and general appearance, but distinguished by larger pronotal punctures, duller surface, and yellow elytral spots often coalesced into irregular 'C'-shaped markings; primarily restricted to glade habitats in south-central U.S.
• Acmaeodera ornataOverlaps in range and flower-visiting behavior, but larger (8–11 mm), with bluish elytral sheen, triangular pronotal depression, and more numerous smaller creamy spots rather than larger yellow spots.
• Acmaeodera ornatoidesVery similar appearance but restricted to Oklahoma and Texas; not known from eastern U.S. where A. tubulus occurs.

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