Thursday, August 11, 2011

Oak Caterpillars

You might expect that in a year with a super flush of vegetation, there would be an abundance of animals to eat it. I’ve seen all kinds of moth larvae and they’re eating just about everything that’s growing. I believe these to be larvae of the Orange-tipped Oakworm Moth, but I won’t be absolutely certain until they get a little older. They seem to have run out of food on this particular stem.

The larvae were working hard to consume the leaves of a small Chinquapin Oak. I was wondering how long it would take this bunch to move to a better grazing area.

It looks like they can’t decide who should be first to back up. It’s interesting how the different instars can show differing characteristics. The dark larva looks to have a much larger head cap then the others. I’m guessing that this will change the next time it molts.

I began to wonder what the larvae tasted like. Not to me, but to birds. It seems odd that these guys are just sitting out in the open where hungry birds can easily spot them.

On the back side of the leaf I found a mass of larvae that are more properly concealed. They still seem awfully easy to spot.

The clustered larvae have an interesting defensive strategy that I like to call The Twitch. When disturbed, the entire bunch will begin to snap their upper bodies rapidly back and forth. The movement is quick, with a tiny pause between each snap. It reminds me of a mass of clocks ticking off the seconds. I don’t see how this action would keep a large predator at bay.

The pattern seems to be one of eating the leaf between the veins and then eating the vein. All that’s left of the leaf is the thick central vein.

This is a small tree and the larvae are just getting started. It’s possible that they will strip the tree bare. Luckily this tree is in an ideal location for me to make periodic checks on the progress of the larvae.