Native Species Profile - Red Milkweed Beetle

During summer the woods and fields of Mid-Michigan are filled with thousands of buzzing, crawling, and flying insects; winter is dull in comparison.  Insects may be the thing I miss most about summer.  

One of the best places to find summer insects is on Common Milkweed (Asclepias syriaca).  Everyone knows that Common Milkweed is a host plant for the Monarch Butterfly (Danaus plexippus), but is also host to many other insects.  My favorite of these is the Red Milkweed Beetle (Tetraopes tetrophthalmus).  

Red Milkweed Beetle - note warning coloration of red with black spots

Red Milkweed Beetles can be found anywhere Common Milkweed grows.  Like the Monarch Butterfly, the Red Milkweed Beetle is able to consume milkweeds without being affected by the toxins that the milkweed produces.  Instead it stores the toxins within its own body and uses them as a chemical defense of its own (as does the Monarch).  Also like the Monarch, the Red Milkweed Beetle advertises these toxin by displaying  warning colors: red or orange-red with black spots.  These warning colors are also known as aposematic coloration.

Mating Red Milkweed Beetles

Red Milkweed Beetles are also known as Four-eyed Milkweed Beetles.  Each of their compound eyes is bissected by its antennae, giving the appearance that the beetle has four eyes.  

These beetles are commonly found in mid- to late-summer as they feed and mate on Common Milkweed.  After mating, eggs are laid on the plant's stem near ground level. The beetles overwinter as larvae in the roots of milkweed plants, pupate in spring, and then emerge as adults.  As adults, these beetles measure 0.3 - 0.6 inches long.

Red Milkweed Beetle (AKA Four-eyed Milkweed Beetle)

Basic Information

Red Milkweed Beetle 
Tetraopes tetrophthalmus

Size: 0.3 - 0.6 inches long (8 - 15 mm)

Color:  red or orange-red with dark spots

Habitat:  Found wherever Common Milkweed grows

Eats:  Milkweeds, especially Common Milkweed (Asclepias syriaca); Dogbane