Reflections on the Locust Borer & Black Locust Tree

Locust borer on goldenrod

Pausing to observe a stand of falltime goldenrod nodding in the wind, you’ll likely find a plethora of buzzing wasps and bees in search of sweet nectar and protein-packed pollen. But among these pollinators sits a zig zag-adorned mimic, the Locust borer. This longhorn beetle often feeds on goldenrod pollen as an adult, using its bright stripes and spindly, wasp-like legs to avoid predation by passing off as its stinging counterparts. Its eggs are laid carefully in the openings of a Black locust tree, hatching as larvae that overwinter in the safety of the tree and awaken to continue munching on its xylem in the spring. Locust borer eggs are mainly only laid inside Black locusts and its cultivars.

Both the Locust borer and Black locust tree used to only be found in the mountain ranges of the eastern United States. But the speed and hardiness of the Black locust’s growth made it a popular ornamental and utilitarian tree, bringing it across North America and with it, the Locust borer. Black locust trees grow especially fast and are tolerant to harsh conditions, making them favorites of reforestation endeavors on former farmland and other poor or eroded areas. The hardwood is strong and rot-resistant, a very valuable material that has been used by humans in North America for many, many years.

Some say that Black locusts could have been the most economically valuable timber if it were not for the Locust borer. Often, Black locust trees grow strong for a few years before getting fairly injured due to the continual boring of the larvae, which weakens branches and gnaws through tree trunks, leaving the wood devoid of commercial value. Yet perhaps the Black locust is grateful to the Locust borer, for it is the borer who has saved it from being relegated to an existence that solely revolves around commodification and the churning of profit.