Red Milkweed Beetle

The red milkweed beetle, Tetraopes tetrophthalmus. 

The red milkweed beetle is another nice summer insect. It's a longhorned beetle, in the family Cerambycidae. Check out its extreme antennae.

The red milkweed beetle's genus and species names are derived from Latin and mean four-eyed. Many species in the longhorned beetle family have antennae that originate close to the eyes, some so close that the eyes look indented. In the red milkweed beetle each compound eye is completely separated into two by the placement of the antennae and violà -- four eyes!

Click to enlarge and check out the antenna with an eye on each side. 

Red milkweed beetles are among the few things that can eat the toxin-containing plants of the milkweed genus, Asclepias. They are able to store the toxins and end up unpalatable to potential predators, which they advertise with their showy colors.

Red milkweed beetles are not the only red and black insects you can find on milkweeds. I've written about two others: large and small milkweed bugs. The red X on its back identifies this small milkweed bug, Lygaeus kalmii. 

The ones with a broad black band across the back are called large milkweed bugs, Oncopeltus fasciatus. You can read a blog I wrote previously about these bugs by clicking here.  And another blog about both kinds by clicking here. 

Combined with monarch butterflies, that are also milkweed specialists in the caterpillar stage, red milkweed beetles and large and small milkweed bugs make for exciting times in the milkweed patch for insect enthusiasts.

Milkweed Bugs, Large & Small

Last year I wrote a blog about the milkweed bug Oncopeltus fasciatus, which is also called the large milkweed bug. It's the kind I usually see on milkweed stems and leaves or sunning themselves on objects near milkweed. (Click here for that blog.)

Large milkweed bugs, Oncopeltus fasciatus, sunning on a fence rail. Adults sport a bright pattern of two black spots and a wide black band on an orange-red background. 

This week I stopped to look at the milkweed bug pictured below. It was sitting on milkweed flowers where its colors contrasted beautifully with the pink and cream blossoms. Looking more closely I saw by the pattern on its back that it was not the kind I usually see. It was the other milkweed bug: Lygaeus kalmii, also called the small milkweed bug.

A small milkweed bug, Lygaeus kalmii. The adult pattern is usually described as a red X on black, but I see a black heart and three red triangles on a red background. 

Like large milkweed bugs, small milkweed bugs also mainly eat milkweed seeds, piercing them with a sharp beak, injecting enzymes, and then sucking up the dissolved food. Both kinds of milkweed bugs also sometimes drink nectar from flowers -- the one above may have been having a sip when I spotted it.