Large Milkweed Bugs on a Common Milkweed pod. One adult is at the top (he has wings), two fifth instars are at the bottom (they are nymphs, or immature versions of the Large Milkweed bugs--notice that they don't have usable wings yet.)
Milkweed bugs molt five times (nymphal instars) before they become adults. During these stages, the nymphs look similar to the adults except their color pattern is a little different and they do not have fully developed wings (during the middle instars black wing pads start to form, but they can not use their wings until they are adults--a great way to keep the kids at home and safe until they grow up).
Close-up of a middle instar. You can see the black wing pads. He's definitely not flying anywhere with those things! Eggs hatch in about a week if the temp is 75 degrees F or above. The bug goes through the five molts to become an adult in about a month! The adult then lives for about a month.
Three adult Large Milkweed Bugs and two instars.
At the tip of the Milkweed pod a group of adults are massing together to form a color warning to birds and other predators.
This behavior is thought to amplify the Milkweed bug's ability to broadcast a color warning. Since Milkweed bugs eat milkweed, which is toxic, they do not taste good. A young bird will think twice before downing another orange and black bug the second time it comes across one...and a great big mass of orange and black is a big warning to stay away! This is the same sort of protection Monarch butterflies receive because as caterpillars they too feed on Common Milkweed. Click here for an older post explaining how Pipevine Swallowtail butterflies and Monarch butterflies receive the same protection (and for a look at how beautiful Common Milkweed is as a flower in the summer).
I love how delicate their legs look against the silk of the milkweed seeds.
What do we have here? At first I thought it was a different bug, but if you look closely, you can see it's an adult with abnormally developed wings. For some reason they have shriveled and dried up. Perhaps on his final molt he was not able to pump hemolymph (bug blood) through the veins in his wings to unfurl them. I don't know...
Another view of our adult Milkweed bug's shriveled wings.
You can see how different the Large Milkweed bug looks without wings to cover his body.