Chauliognathus pensylvanicus

Distinguished from the closely related Chauliognathus marginatus by its strong preference for yellow flowers, particularly goldenrod (Solidago), whereas C. marginatus is more commonly associated with white flowers. Both species prefer Asteraceae, but C. pensylvanicus shows narrower flower family range. Distinguished from other Cantharidae by its specific color pattern and phenology. May be confused with other yellow-and-black beetles such as Megacyllene decora (amorpha borer) and M. robiniae (locust borer), but soldier beetles have softer, more flexible elytra and lack the robust form of cerambycids.

Found in open habitats including meadows, fields, roadsides, and gardens where goldenrod and other Asteraceae are abundant. Also occurs in woodland edges and disturbed areas. Larvae occur in soil, leaf litter, and beneath loose bark. Adults frequently visit human-modified environments such as flowerbeds and landscaped areas.

Native to North America. Documented from Canada (Manitoba, Ontario) and throughout the United States. Widespread and common across its range.

Adults active primarily in late summer and autumn, with peak activity coinciding with goldenrod bloom. Larvae present in autumn and overwinter in soil or protected locations. Adults emerge after pupation in spring.

Adults are predatory, feeding on soft-bodied plant pests including aphids and caterpillars. Adults also consume nectar and pollen from flowers, particularly Asteraceae. Larvae are predatory on ground-dwelling insects and will ascend plants to hunt in flowers and on foliage.

• Solidago - adult food source (nectar/pollen)strongly preferred; primary common name derives from this association
• Asteraceae - adult food sourcefamily-level preference for flower visitation
• Eupatorium - adult food sourceoccasionally visited

Complete metamorphosis with four stages: egg, larva, pupa, adult. Larvae are dark grey, velvety, and covered in fine hairs. They pass winter in soil, under leaf litter, or beneath loose bark. Pupation occurs in spring, with adult emergence following. Mating occurs throughout adult activity period.

Adults are diurnal and active on flowers. Mating behavior is frequent and conspicuous; females are selective and prefer larger males, which are better able to subdue resistant females. When infected by Eryniopsis lampyridarum, beetles exhibit "summiting" behavior: climbing to upper leaves, clamping onto vegetation with jaws, and spreading wings post-mortem to facilitate fungal spore dispersal.

Important predator of agricultural and garden pests in both adult and larval stages. Contributes to biological control of aphids and caterpillars. Serves as a model for Müllerian or Batesian mimicry complexes involving other yellow-and-black insects. Acts as host for fungal entomopathogens that may regulate population dynamics.

Considered beneficial in gardens and agricultural settings due to predation on pests. Sometimes enters homes in autumn when larvae seek shelter, but easily relocated without harm. Subject of behavioral research on sexual selection and mate choice. Used in studies demonstrating the utility of citizen science data for ecological research.

• Chauliognathus marginatusOverlaps in distribution and flower visitation; distinguished by C. marginatus preference for white flowers and broader flower family use
• Megacyllene decoraSimilar yellow-and-black coloration on goldenrod; distinguished by harder elytra, more robust body, and larger size of cerambycid beetles
• Megacyllene robiniaeSimilar color pattern and phenology; distinguished by host association with black locust and morphological differences typical of longhorn beetles

• soldier beetle
• goldenrod
• beneficial insect
• predator
• entomopathogen
• sexual selection
• flower visitor

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Amorpha borer on goldenrod | Beetles In The Bush
• Bug Eric: I Am Not a Scientist
• Bug of the Week
• Pixelated Entomology: Analyzing Beetles' Flower Use Through Digital Samples
• Soggy death to friendly soldiers: Soldier beetles, Chauliognathus pennsylvanicus, and their deadly fungus, Entomophthora lampyridarum — Bug of the Week
• Gelechiidae | Beetles In The Bush