The goldenrod soldier beetle (Chauliognathus pennsylvanicus), also sometimes called Pennsylvania leatherwing, is generally considered a beneficial insect, as its diet includes various common plant pests. Understanding and preserving beneficial insects like this beetle helps minimize the need for potentially harmful pesticides. This beetle may occasionally venture indoors, especially as temperatures begin to drop in fall, where it is primarily considered no worse than a nuisance, as it will not bite or sting people or pets.
The adult goldenrod soldier beetle measures about 5/8 inch long and has an elongated body. This insect has soft, flexible wing covers known as elytra. The elytra are orange with two large black spots near the end. The antennae and legs of the goldenrod soldier beetle are long and slender. The larvae of this beetle grow up to 3/4 inch long and are slender and dark-colored with a body that appears stippled and is covered with tiny, dense bristles that give the larvae a velvety look.
The goldenrod soldier beetle adult lays eggs at the end of summer. Larvae promptly hatch and overwinter in damp soil or debris or under loose bark before becoming active in spring when the soil warms. The larvae tend to occur in sites with high humidity. These predaceous larvae pupate in early summer, emerging as adults in late July or August.
In the Garden
Adult beetles primarily feed on flower pollen and nectar but this feeding does not damage plants and may help with pollination. Both adult beetles and larvae feed on insects that are often considered plant pests. The larvae feed in the soil, consuming the eggs of grasshoppers and other insects, small caterpillars and soft-bodied insects, like aphids. Adults eat the same types of pests.
Beetles in the Home
Adult beetles may occasionally enter a house during the summer by accident and larvae tend to venture indoors in the fall in search of a sheltered spot to overwinter. If you find them in your home, sweep or pick them up and put them back in the yard, far away from the house. Prevent them getting in your house by caulking potential entry points, weather-stripping and otherwise sealing all possible openings.