Male and Female Monkey Beetles

2015 October 10

These beetles were all over the dogwood blossoms out back on June 8, 2015, so we brought a bunch of them back to the house for pictures.

At first, we thought that there were two different species – brown ones, and black ones. But then we noticed that a lot of the black ones were busy mating with the brown ones, and we realized that they were all one species and this was just a sexual dimorphism.

They are clearly scarab beetles, as they have the characteristic body shape, and the short antennae with “fingers” on the tip.

They look like Monkey Beetles[1] in the genus Hoplia, and the male looks a lot like the monkey beetle species I’d found previously. Based both on appearance and the range maps, I think they are most likely Hoplia trivialis. I thought at first they might have been the related “Three-Lined Hoplia”, Hoplia trifasciata, since BugGuide shows the brown females for them, and not just the black males. But, the three-lined hoplia has bands running across the wing covers, and I really don’t see any distinctive “three lines” on either of my specimens.

At any rate, they seem very fond of flowers, so I expect that the adults are mostly eating pollen. Like a lot of scarab beetles, their larvae live underground and eat roots. They look kind of superficially like Japanese Beetles, but they are a native species with a full set of native predators and diseases, so they don’t go into the massive, destructive population explosions like introduced pests do.

[1] They are evidently called Monkey Beetles because they have a tendency to hang by their hind feet from things and sometimes do a sort of somersault.

One Response
  1. October 12, 2015

    You’d better watch out for these beetles. Pollen is a super food.

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