Locust borers (Coleoptera: Cerambycidae: Megacyllene robiniae) are common beetles in many parts of the United States. While adults can feed on pollen from a variety of flowers, they have a distinct preference for goldenrods (Solidago spp., Asteraceae). These widespread plants flower in late summer and autumn when the adult beetles emerge, making them an abundant and convenient food source.
Locust borer larvae, in contrast, feed on the wood of black locust trees (Robinia pseudoacacia, Fabaceae). In autumn the adult females lay their eggs on these trees, and the larvae quickly hatch and bore into the wood. The young overwinter within the trees and begin tunneling and feeding again in the spring. They pupate in mid-summer and emerge as adults by early autumn, ready to repeat the life cycle.
Locust borers and their black locust larval hosts were historically limited to the Appalachian and Ozark highlands of the United States. After Europeans arrived in North America they soon discovered great value in black locust timber. The hard, strong, rot-resistant wood made it ideal for a variety of applications, so settlers planted these trees far and wide. As the range of these trees quickly spread across the continent, so did the range of locust borers. Today both black locusts and locust borers can be found throughout much of the United States, especially in areas that also host goldenrods for the adults to feed on. Since black locust continues to be a commercially valuable tree, locust borers are considered a serious pest.