In a recent post called Saving Monarch Caterpillars I asked the question of what happened to all our monarch caterpillars. Now I am wondering: “Were our Monarch caterpillars eaten by praying mantis?” I thought Monarchs were protected by eating Milkweed which has cardenolides in it. This chemical is toxic to many vertebrate predators. But that was not to be the case. Out of all the caterpillars we saw we only found 4 that made it to maturity. That doesn’t mean that there weren’t more because maybe we didn’t see them. And we saved 12 caterpillars that we raised to maturity and released.
Evidence for Monarch Caterpillars Eaten by Praying Mantis
A strange sequence of events happened this year in my garden that I am just now piecing together. A neighbor of mine bought a gift for me–2 egg cases of praying mantises. We are both gardeners and the praying mantis is a good addition to an organic garden because they eat a lot of bugs. I put one egg case in my front garden near to where my common milkweed Asclepias Syriaca was growing. This is the second year of my common milkweed. I have had Butterfly Weed or Asclepias tuberosa growing in my garden for years but it never attracted the Monarch butterfly. It attracted lots of pollinators but not the Monarch. It was scattered in the garden. Maybe it needed to be clumped together for the Monarchs to notice it.
So I don’t know how many praying mantises came out of that egg case. I did see the one in this picture on the wall next to our front door. This wall is next to the Milkweed. A perfect spot to look for his next meal. It just astounds me that we had so many caterpillars and then they disappeared.
Lessons to be Learned
So were the monarch caterpillars eaten by praying mantis? I don’t know for sure but if I see any more praying mantis in this butterfly garden I am going to remove them to the back vegetable garden. And if you are given or find a praying mantis egg case put it in your garden far away from butterfly host plants. The praying mantis will also eat a butterfly. We just have to remember that this is the circle of life.
Click on the link for more information from National Geographic supporting the question of were the monarch caterpillars eaten by praying mantis?