Interesting Caterpillar Behaviour

[jwa121]

Some time ago, I was lucky enough to be able to rear a few caterpillars of the South American Saturniid moth species Rothschildia erycina. I reared these caterpillars on Privet (Ligustrum ovalifolium).

One of my mature (fifth instar) erycina caterpillars spun a cocoon (indoors, on a cut Privet branch) and then abandoned this (very advanced) cocoon, only to then begin a second cocoon, a short distance away, on a different Privet stem.

The abandoned cocoon was very advanced. It looked substantially complete. The caterpillar was not disturbed in any way. So I was surprised when the caterpillar abandoned the cocoon and began a second one, nearby.

After spinning a superficial second cocoon, the caterpillar abruptly left the (very incomplete) superficial second cocoon, and returned to its original, substantially complete, first cocoon.

The caterpillar then proceeded to try to re-enter this original, advanced, first cocoon, rear end first. Picture a very fat person trying to pull on a pair of very skinny jeans. I didn't think the (bulging) caterpillar was going to be able to get back inside. But it did!

The caterpillar then resumed work on this first cocoon and the finished cocoon looked absolutely perfect.

Presumably, the caterpillar retained a memory of the substantially complete first cocoon and, at some point (decided?), to return to it. Makes you wonder.

I thought it was an intriguing bit of behaviour. It was a little unsettling to watch this very careful, deliberate behaviour. A mind at work?

Saturniid caterpillars will (occasionally, it's rare) abandon a cocoon and spin a new one elsewhere. But to see this caterpillar return to its original effort and to see it carefully and deliberately squeeze itself back inside was remarkable, I think.

John

[eurytides]

That’s very cool. Do you have pictures? If you do, you could consider publishing the observations.

[jwa121]

Thanks for your comment. I wish now I had photographed the caterpillar ever so slowly squeezing itself back inside the (temporarily) abandoned cocoon. I guess I’ll have to settle for publishing my observation here.

John

[kevinkk]

It is interesting, I don't think I've had a larva do that in particular, but they do sometimes go off script. Raise enough and eventually you'll see nearly
everything. Nearly. Yes, only one chance to get pictures usually.