BEETLES OF EASTERN NORTH AMERICA: GOLDENROD SOLDIER BEETLE
By Arthur V. Evans
Late summer and early fall is the time for goldenrod soldier beetles, Chauliognathus pennsylvanicus (DeGeer). Adults feed on pollen from various flowers, especially goldenrod (Solidago), growing in gardens, parks, fields, meadows, and along roadsides and woodland edges.
These conspicuous beetles are often used as research subjects by scientists studying mating behavior, color polymorphism, dispersal, and genetics. This common and widespread species is found over much of eastern North America, ranging from southeastern Canada south to Florida, west to Colorado and Texas.
The head of these conspicuous and aposematically marked beetles is black and the pronotum is wider than long. By contrast, the head of the early spring/early summer margined leatherwing (C. marginatus), has a thick v-shaped mark, while the pronotum is longer than wide. The dark elytral spots of both species are either confined to the posterior half of elytra or extend along their entire length.
Dead and contorted soldier beetles are sometimes found on plants with their mandibles imbedded in stems or leaf edges. These beetles have succumbed to an infection by Eryniopsis lampyridum, a fungal pathogen that also attacks other insects. The open wings of the fungal victims are thought to enhance dispersal of the killer fungus’ spores.
© 2010, A.V. Evans