I don't think it can either.

I keep a lot of food available for my PVS cats so this doesn't happen. It only happened once, and that was a long time ago when I first started raising them. After that, I started provided AMPLE food (more than it looks like they need) so they can travel back and forth from leaf to leaf when they want) and it never happened again. Of course, I've got lots of mature vines that make LOTS of leaves, so it's easy for me to do.

Sherry

Many of us have learned hard lessons because we have witnessed the same things that you have.

Over crowding, lack of food, leaving smaller caterpillars/eggs in the same container with older/larger ones, leaving chrysalis in a container with munching caterpillars. All of these are possible causes of cannibalism. Some species have a reputation for cannibalism, for example, Spicebush and Zebra Swallowtails. Small Monarch caterpillars will eat eggs. It is best to separate them from unhatched eggs into their own containers.

One thing to think about is that caterpillars have simple eyes so they don't see very well. Their roommates are made out of the very host plants that they are consuming.