Here’s another very nice picture that Michelle[1] took up on Whealkate Bluff [2](the same place she found the grasshopper posted last week). It’s a White-Marked Tussock Moth caterpillar, Orgyia leucostigma, perched on a ripe wild raspberry:

I personally think this one looks very nice (If you agree, Michelle has prints of this image available here). The picture shows the back and tussocks nicely, including the red defensive glands on the back and the two long guard hairs on either side of each tussock. I think the long hairs are sensory hairs, so that if something touches them the caterpillar knows to roll up with the tussocks pointing out.

These are very distinctive caterpillars that really stand out when you find them. The general advice is not to handle them, though. The hairs are irritating, and can give dermatitis or even allergic reactions. This, of course, is how they get away with being so obvious – they are too nasty to eat.

They themselves aren’t too picky about what they eat, they apparently will take plants ranging from hardwoods like apple and birch, to conifers like hemlock and spruce. I’m not seeing any reference to them eating raspberry leaves, but I would not be at all surprised, especially since this one is obviously on a raspberry plant. In some parts of the country (particularly further south), they are reported to sometimes have major outbreaks that defoliate whole forests, but it evidently doesn’t happen here.

These are one of a number of moth species where the females don’t actually have wings. After they pupate, the females just pop out of their pupas and start giving off pheromones, and the males (who do have wings) home right in on them. Then the female (who doesn’t even come out of her cocoon) lays a mass of eggs all over herself, covered with a protective froth. The eggs overwinter, and it all starts again the next spring. Futher south the evidently have two generations per year, but here I think there is only one generation. An interesting side effect of the winglessness of the females is that they can’t actually spread or migrate by flying, so they can only expand their range as fast as the caterpillars can walk. The males can fly around, but they can’t reproduce unless they find a female wherever it is that they get to, so they can’t actually colonize any new areas. In spite of this, they are very widespread, and seem to be common throughout most of eastern North America. Since the caterpillars have to be the life stage that actually does most of the moving around, this is probably why we often see them marching along through the grass or crossing roads.

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[1] In addition to individual prints for sale here,, she also has a nice 2009 calendar here.

[2] Whealkate should probably be a lot more well-known than it is, considering that it is not only a fairly prominent landmark, but actually has quite a bit of history tied up with it. It’s mentioned in Michigan’s Copper Country, by Ellis W. Courter (Contribution to Michigan Geology 92 01), as the site of the first copper mine in the Portage Lake district. The problem, though, was that it had some embarassment issues that probably kept it from getting much publicity. As Courter puts it:

The Whealkate, like most of the early mines, ended up as a dismal failure. According to Horace Stevens, author of The Copper Handbook, the Whealkate was the most unusual example of mining ever attempted in the Copper Country. He goes on to say: “The mine should be dug up bodily and preserved for engraving upon the intellect of those who would be admonished. It is probably the finest example extant of how not to do it!”
The absurdity began with the first shaft which was said to have been sunk in quick-sand. It had to be abandoned due to the presence of a great amount of water. A second shaft was then sunk in the trap rock for forty feet. From that shaft, a drift was sent south for twenty feet. Then an incline shaft was sunk fifty feet. From the bottom of this shaft, a cross cut was sent one hundred feet to a supposed copper lode. A final drift was sent south for another fifty feet. In this location a winze was sunk 540 feet. These haphazard attempts did not find any copper.