Monarch butterflies and caterpillars have various predators in spite of their defenses. They also have to deal with parasites and diseases. This page will show photos and videos of different situations that didn’t turn well for the insect.
The seventeen caterpillars I raised however all turned out as healthy looking butterflies.
YELLOWJACKETS AND BALD-FACED HORNETS
These insects are predators that feed their young with other insects including caterpillars. However their own diet as adults is sugars such as nectar from flowers. From what I could observe they would not bother the large Monarch caterpillars feeding on the same flowers of the Swamp Milkweed. Which doesn’t mean that they did NOT prey on young caterpillars though.
THE CHRYSALIS UNDER AN INUKSHUK STONE
One morning I found a Monarch chrysalis under the stone below the shoulder stone of the inukshuk in my garden. That stone structure is around one meter (3 ft.) from a Swamp milkweed clump, but it sits on a raised bed of stones surrounded by a large wooden board.
How this caterpillar was able to crawl across all those obstacles to reach almost the top of the one meter (3 ft.) high inukshuk is a mystery to me!
Unfortunately, the chrysalis didn’t look right. It had what seemed like a hole and a transversal crack in the middle on one side.
However its color seemed to indicate it was near emerging as a butterfly, but instead it turned completely black after a few days while remaining intact (no parasitic larvae came out of it). And after a few weeks, it had disappeared completely.
THE EMPTIED CATERPILLAR
The same morning I found the above chrysalis under the inukshuk, I also found a dead caterpillar that looked like its interior had been sucked out.
It was hanging down from the underside of a Dusty Miller leaf near the Swamp milkweed clump where it came from, so it was in the ‘J’ stage.
And there was this shriveled and shrank Monarch caterpillar with some silk attached to its end. Was it killed by a spider?