If you ask kids that question they might answer, “Monarch Caterpillars.” And they’d be right. But there are many more critters that eat milkweed, too! I haven’t seen a Monarch yet this year, though friends around the area are reporting them already. I have seen another milkweed muncher:
Swamp Milkweed Leaf Beetle (Labidomera clivicollis). In late spring, after the milkweed is up, adults begin crawling up out of the leaf litter where they overwintered. They will feed on milkweed leaves and flowers, and they will mate. Eggs will be cemented to the underside of milkweed leaves. Swamp Milkweed is preferred, but they can sometimes be found on Common Milkweed as well.
In mid-summer, you may not see many adults. Those that overwintered will die soon after laying eggs. I have never found the eggs of this beetle. I did a Google search to see if anyone had posted a photo of some, so I would know what to look for. Aren’t they pretty? I’ll search today while out on my Dragonfly Hunt. I can multi-task! (By the way, be sure to click on that picture of the eggs to see the amazing series of photos taken by Wayne.)
When the larvae emerge, they look nothing like the adult beetle. They also eat milkweed leaves and flowers. This photo is from the Cornell Entomology department. I haven’t seen larvae yet this season.
Larvae will drop to the ground to pupate. In late summer, adults will emerge and you should find them chowing down on milkweed plants again.
In case you want to go hunting for this pretty beetle, too, here’s a picture of Swamp Milkweed that I took last summer. Oh look! There’s another species crawling all over it… Hmmm… That will have to be a lesson for another day!