I don't know about caterpillars, but I will use this opportunity to tell my butterfly story. LOL
Butterflies spawn on or around Forestry trees, pretty much as simple as that. I was playing on a multiplayer server and had 8 Chestnut trees since those nuts produce the most seed oil for my frames, etc.
So over the course of a few weeks or perhaps a month, day after day, around the clock, my chunk-loaded base kept spawning butterflies. Eventually I made a jetpack and began to fly to and from my base, and I discovered something very interesting, and not in a good way.
At the very edges of my chunk-loaded area, where the chunk-loading ends, just on the other side of those chunk lines...... were THOUSANDS of butterflies. There were so many that my frame rate was crippled.
Apparently what was happening was that butterflies were spawning non-stop around my Chestnut trees... and eventually just thru their random flight, they would cross the chunk loading boundary... and obviously they would halt/freeze just on the other side... and they ended up collecting in some astounding numbers. LOL Tens of thousands of butterflies.
So I told the server operator the situation, and he worked some admin magic to delete all butterflies on the server, which took him a little bit of time to successfully figure out how to do it... and all was well once again. Since that day, the "Butterfly Incident" is often met with laughs when the subject is brought up in discussion. haha
So... the moral of the story? ALWAYS ENCLOSE YOUR FORESTRY TREES IN A GLASS STRUCTURE (or similar) SO THE BUTTERFLIES CANNOT GET OUT AND WREAK HAVOC ON YOUR WORLD!
