Ants in Winter: Part 1 Camponotus in Diapause

Last week I got a peek at where Camponotus pennsylvanicus carpenter ants spend the winter.

The temperatures were hovering around freezing in upstate New York, where I was helping someone spit firewood.

When the wood split, occasionally we would find tunnels, hardly more than grooves in the wood, packed with ants. Although the ants look like they might have been moving, they were mostly stiff and inactive. You could shake them out onto the ground without much resistance.

This group was in softer wood with more decay. Notice the larva. Most of the clusters of worker ants had small larvae with them.

Camponotus carpenter ants that live in temperate climates enter a state of slowed metabolism, called “diapause”, in the late fall and through the cold parts of the winter. Generally, the queen stops laying eggs. The workers begin to aggregate more than before. The workers develop large fat bodies, which can be seen as their gasters swell in size, as well as produce glycerol. Glycerol is an alcohol that helps prevent the formation of ice crystals within the ants’ bodies. No wonder the ants stagger a bit when they try to move. 🙂

What are ants doing this month where you live?

For more information try:

Cannon, C. A. 1990. Demography, cold hardiness, and nutrient reserves of overwintering nests of the carpenter ant, Camponotus pennsylvanicus (De Geer). M. S. Thesis, Virginia Polytechnic Institute and State University. 165 pp.

Cannon, C.A. and R.D. Fell. 1992. Cold hardiness of the overwintering black carpenter ant. Physiol. Entomol. 17:121-126.

Seed Cache

The ants are still active here, but I haven’t had much to report. In an effort to get back in the swing of things, I will be posting some short notes.

Do you know what this is? I tipped over a rock near a Southern fire ant nest and found this cache of tiny seeds. It is easy to forget that fire ants also harvest seeds.

I should have picked up a couple of the seeds to try to sprout them. It wasn’t obvious where they came from, as there weren’t any plants nearby.

Have you ever found seed caches in fire ant nests?

Pogonomyrmex Raids

Although I confidently say they are raids in the title, let’s see the evidence:

First, I came across this harvester ant nest with dead ants, about half of which are light-colored callows. No live ants to be seen.

A nearby entrance hole had a lot more activity. The workers are actively grabbing each other.

By the way, the seed was going out, not in.

From out of the nest came workers carrying callows.

Here’s another one.

Up out of the nest…

… and off it goes.

This one is carrying a worker.

After a short while, the excitement died down a bit.

When Pogonomyrmex raid weaker colonies they are known to carry off larvae and pupae. I didn’t see any of that, but I couldn’t watch that long, either. We were at a park and kids were playing.

What do you think? Was it a raid?

In another note, James asked about the color of the silverfish.

It appears to be creamy-silvery in color. It didn’t stay outside for long though. It zipped out and zipped back in. The quality of the photograph leaves a tad bit to be desired.