Soft-winged flower beetles are colorful little critters often found on spring blossoms. Beetles in the family are usually about the same shape (ovoid) and small size (2 to 7 mm) but there’s lots of variation—There are over 520 species in the U.S.
Melyridae family adults are omnivores like us, although their meat sources are insect-based and their plant diet is pollen. Larvae primarily eat other insects while they’re growing up under tree bark.
I found this Malachius auritus the other day near Mt. Pisgah’s east entrance. Like other soft-winged flower beetles, its elytra don’t reach the end of its abdomen, and you can see the thin, transparent flight wings underneath. The side view on the buttercup shows off some impressive, jagged antennae.
If, like me, you think the saw-blade antennae are cool, you’ll be even more impressed with some of the other insects in this family. Some beetles in the Collops genus have large knobs on their antennae, not at the end, but closer to the eyes. Collops seem to prefer drier climates; the ones in Oregon are found in the high desert. And some Malachius species have antennae with the profile of a wide-toothed comb. Entomologists call the shape “pectinate,” from the Latin word for comb.
Males in some Malachius species from Europe have glands on their lower antennae that create a substance that attracts females. It’s easy to tell males from females by the enlarged first segments. These “common” Malachite beetles shine a blue-green tone in the sun with red spots on the lower abdomen. There is a similar-looking beetle at Mt. Pisgah, and I’ve seen a red and black soft-winged flower beetle as well.
Stay curious!
See more of Karen’s work here.
Sources:
To see a Malachius genus beetle with pectinate antennae: https://bugguide.net/node/view/1963665/bgimage. And for a Collops beetle with knobby antennae: https://bugguide.net/node/view/644860. Accessed 4/29/22.
Information on females feeding on male antennae secretions: The Encyclopedia of Land Invertebrate Behaviour, 1993: https://bit.ly/37Uobgb. Accessed 4/29/22.
