Epicauta pensylvanica

The all-black or nearly all-black coloration distinguishes E. pensylvanica from many congeners that display prominent yellow or gray stripes or spots. It may be confused with E. funebris, which also tends toward dark coloration, but E. pensylvanica typically lacks the distinct pale markings found on the pronotum and elytra of that species. The species can be separated from dark soldier beetles (Cantharidae) by the head being wider than the pronotum and the more cylindrical body form. Final identification requires examination of male genitalia or association with host plants and geographic range.

Adults are elongate, soft-bodied beetles approximately 12–15 mm in length. The body is predominantly black with a somewhat velvety texture. The head is wider than the pronotum, and the antennae are relatively long and thread-like. The elytra are flexible and may show subtle longitudinal striations. The overall body form is typical of Epicauta blister beetles, with a somewhat cylindrical shape that tapers slightly toward the posterior.

Open habitats including prairies, grasslands, and agricultural fields. Adults are frequently associated with flowering plants, particularly in the Asteraceae family. The species is often found in areas with abundant snakeweed (Gutierrezia sarothrae) and related composite flowers. Larval habitat is poorly documented but likely involves soil-dwelling predation on grasshopper egg pods, as is typical for Epicauta species.

Widely distributed across North America, with records from the United States and Canada. The species has been documented from the Great Plains through the Midwest and into the northeastern United States. GBIF records indicate presence in Middle America and North America. Specific state records include Oklahoma, where it has been collected in shortgrass prairie habitats.

Adults are active primarily from late spring through early fall, with peak activity during summer months. In Oklahoma, adults have been observed in October. The species likely has a single generation per year, with adults emerging in late spring and persisting until frost.

Adults feed on foliage and flowers of various plants, with particular association to Asteraceae. Documented feeding on Gutierrezia sarothrae (snakeweed) flowers and soybean foliage. Larvae are predaceous, feeding on grasshopper egg pods in the soil.

• Gutierrezia sarothrae - adult food plantFrequently observed on flowers; primary common name 'black aster bug' derives from this association
• Glycine max - pestDocumented as defoliator of soybean in agricultural settings
• Asteraceae - adult food plant familyGeneral association with composite flowers

Complete metamorphosis with hypermetamorphic larvae typical of Meloidae. Eggs are laid in soil. First instar larvae (triungulins) are mobile and seek out grasshopper egg pods. Subsequent larval instars are grub-like and feed within egg pods. Pupation occurs in soil. Adults emerge in late spring. Detailed life history studies specific to E. pensylvanica are lacking; the above is inferred from the genus Epicauta.

Adults are diurnal and frequently observed on flowers, where they feed on pollen and nectar. When disturbed, adults may exude cantharidin from leg joints and body segments as a chemical defense. The species has been documented moving en masse into soybean fields from field margins late in the season. Adults are capable of flight and may aggregate on preferred host plants.

Adults function as herbivores and pollinators on wildflowers. The species is a documented pest of soybean, capable of causing significant defoliation when populations are high. Larvae serve as biological control agents of grasshoppers through predation on egg pods. The chemical defense (cantharidin) makes adults unpalatable to many predators, potentially contributing to Müllerian mimicry complexes with similarly colored beetles.

Agricultural pest of soybean, particularly in the eastern United States. The species can cause rapid defoliation when adults move en masse from field margins. Blistering chemical defense poses minor hazard to humans handling specimens; cantharidin can cause skin irritation and blistering. No documented veterinary importance from this specific species, though related blister beetles are of concern in hay fed to horses.

• Epicauta funebrisAlso predominantly black, but typically shows distinct pale pronotal and elytral markings absent in E. pensylvanica
• Chauliognathus basalisColorado soldier beetle with similar black-and-orange pattern in Müllerian mimicry complex; distinguished by more parallel-sided body form and head not wider than pronotum
• Epicauta vittataStriped blister beetle with prominent yellow and black longitudinal stripes; more distinctly marked than typically dark E. pensylvanica

• blister beetle
• Meloidae
• soybean pest
• cantharidin
• Asteraceae feeder
• North America
• agricultural pest
• chemical defense
• Müllerian mimicry

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Meloidae Holdings | Entomology Research Museum
• Portrait of a Yellowjacket | Bug Squad
• Soybean Insects: Early-to-Late Season Pests (Emergence to R7) - AgriLife Extension Entomology
• Insecta | Beetles In The Bush | Page 3
• Archive — Bug of the Week
• Bug Eric: A Beetle Mimicry Complex