Pollinating Beetles on Goldenrods: Locust Borer and Goldenrod Soldier Beetle

A few of the many goldenrods in Eliza Howell Park are starting to bloom and I have modified my walk to include these early blooming patches. Goldenrods attract many insects, which in turn attract me.

Pollinating insects include bees, wasps, flower flies, butterflies, and moths. In goldenrod season I am reminded that some beetles are also active pollinators.

Today I was watching two very attractive pollinating beetles in a goldenrod patch. One is known as the Locust Borer.

The Locust Borer is so named because it uses the Black Locust tree as the only plant species for the growing the next generation. It lays its eggs in a crevice in the bark of a Black Locust tree and, when hatched, the larvae burrow into the tree to spend the winter. (It does not use the Honey Locust trees also found in Eliza Howell.)

I do not know why, but it seems to favor goldenrod flowers when feeding on nectar and pollen.This preference makes for some good photo opportunities.

The other pollinating beetle I was watching today is the Goldenrod Soldier Beetle.

“Soldier beetles” are named that because the wings on their back reminded someone of the long coats worn by soldiers in the eighteenth century (“the redcoats”). This particular soldier beetle is identified with goldenrods because it forages frequently on goldenrods — where it sometimes meets the larger Locust Borer.

Goldenrod Soldier Beetle adults also eat small insects and caterpillars, though much of their time is spent nectaring.

And though they are named for their foraging on goldenrod blooms, they can be found on other flowers as well. This one was on Joe Pye flowers today when I took a closeup.

I am pleased each summer to see these two colorful beetles when they appear, almost always in August. It is not often, though, that I get to see them in such close proximity.

Note the long horns on both.

Different species of goldenrods will be blooming over the next several weeks. And I will likely have more to report follwing my walks among them!

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