Whilst out walking today, several times I came across this curious site of Caterpillars doing the conga. Now I’ve read about Spain’s Caterpillars that live up pine trees and have a mast sting to their hairy appendages, and this was on the tracks through a pine forest, and there were curious spider web like ‘bags’ hanging in the tree branches that even Indiana Jones would have disliked disturbing, and these were Caterpillars – but I’ll reserve judgement on whether these were they – needless to say I avoided touching them!
Anyway, these caterpillars were doing the conga. Long lines of them crossing the track (possibly elsewhere in the undergrowth that I couldn’t see so easily), some chains were maybe a dozen critters long, whilst some were a good 6 feet.
They didn’t appear to be holding on to each other, just following close enough to keep whiskers in constant contact. Occasionally there would be some confusion and there would be a bit of a pile up, and they were quite pushy and bargy with one another to get back in line. I even saw some get really confused and end up in a closed loop going around in circles.
And in addition, sometimes they would suddenly start burrowing on the same spot, a big pile of them all trying to make a depression in the earth. Elsewhere I saw dead groups like this, so it seemed to be some sort of suicide pact.
I can’t explain why they were doing any of this. The digging took to be an attempt to take shelter and huddle together, possibly they feared being stuck on the track overnight, and those that failed to make the crossing perished in the cold overnight temps without sufficient shelter. I assume therefore that the lines were a strategy to try and stick together to increase the chances of survival. How on earth caterpillars learn this when they only have one very short life I have no idea!
Update: Here is the low down on the Pine Processional Caterpillar and the painful consequences of a close encounter