Thursday, June 21, 2012


It's the longest day, the first day of summer. But summer isn't looking as attractive as it did in early spring when everything was mild and wet without being too wet, and things seemed perfect for a good insect year. Now it is hot and dry and everything is set for a drought, which is entomological disaster. This is at least a small part of why I have decided to study grasshoppers: They seem to do all right in a drought. Insects I specialized in in the past, butterflies, dragonflies, robber flies, tiger beetles, are really diminished by drought. Particularly drought alternating with flood, which has been the story the past few years, and all of these groups seem to me to be in poor numbers, and every time I begin to hope they are coming back, we are hit with another drought or flood.

Cheryl however is interested in moths, and makes me think maybe that is a way to go. At least you go out in the cool of the evening to look for them, and usually don't have to go farther than your front porch where you have carefully left the light on, and can whip back inside when the mosquitoes become intolerable. There are disadvantages to moths, of course. There are 11,000 of them in North America and that is sort of hard to get your head around, and they are mainly gray and dull and all look alike. Well that's what I thought, but now I am learning that if you take them one at a time, and especially if you photograph them so you can study them carefully afterwards, they are sometimes really bizarre, and often subtly beautiful. Here's an example of each (you can decide for yourself which is which).

This last one is particularly numerous at the moment. They are sitting on the screens of all our windows at night and make up almost all of the moths that come to our porch light. The problem is, which of the 11,000 species is it? We have been paging through our new Peterson Field Guide to the Moths stopping at groups with this shape, the wings folded like a tent over the body, the head with a cockatoo crest, and have decided it is not a Prominent or a Looper or a Sallow, and we have stopped at Pickerelweed Borer. This is especially appealing because most of the marks on the moth seem right, plus we have never before had a bigger or more flourishing bed of pickerelweed in our pond, which could be the source of this invasion of the adult moths.

We also like this choice (remember it is still guesswork on our inexperienced parts), because it is such a neat moth. Here is its life history (which I am gleaning from Wagner et al., Owlet Caterpillars of Eastern North America): Eggs are laid above above waterline on pickerelweed. The caterpillar hatches out, bores into the plant tissue and goes down under water where it feeds. When it has finished that part of its life, it bores its way out, then floats to the top, and swims ashore (its tail end going back and forth as a snake would swim). It then crawls under old wood or other debris, where it spends the winter, then in spring it makes a cocoon in a cell in the ground or in rotted wood, the adults emerging in early summer to flock to our windows.

This is not the only very visible moth activity at the moment.

Right now there are no Monarch caterpillars using our milkweeds, but they are not going to go to waste. If you turn over a leaf at the right moment here is what you might find:

These are the eggs of the Milkweed Tussock Moth, and these spell something close to doom for the milkweed plants themselves (though they always come back no matter how badly they are defoliated). The Milkweed Tussock Moth caterpillars will come in droves and feed side by side, devouring every leaf of every plant one by one. I wasn't quick enough to notice the eggs this year (the photo is from a previous year). When I first thought to look, they were already hatched and on their way.

Some have already molted out of their earliest stages to show their full tussockness, and also showing their black white and red warning coloring, since they have imbibed from the milkweed the same powerful heart poisons that the Monarch caterpillars ate earlier in the year. When this plant is eaten to the nub (when I took this picture they were only on the third or fourth leaf) they will march to the next and they will join other groups or split up individually and one way or other make sure they visit every corner of the yard.

The Monarch caterpillars turn into the superb Monarch butterfly. These spectacular tussock caterpillars will turn into the plainest jane of all the moths, a complete reversal of the Ugly Duckling story.

This often, it seems to me, is the case with caterpillars and moths, which is why I love caterpillars, but Cheryl can only fleetingly get me interested in their parents.

Postscript: The world (or anyway my world) has a way pushing back against me the moment I make a large general statement, such as "Spectacular caterpillars lead to plain uninteresting moths." I typed those last words, then went into the house from my study to ask Cheryl to look at my blog and prune out the misspellings and gross factual errors. While I spoke to her I glanced at the aquarium on the counter and noticed a big moth that had not been there yesterday. In the middle of May Cheryl had found a spectacular big hornworm on our ash tree, the caterpillar of the Waved Sphinx moth, and we had brought it in and put it in that aquarium.

It was so voracious we had to bring it a new cluster of ash leaves every day. On the 29th of May it buried himself under the loose soil we had prepared for it, and on this day, the first day of summer, scarcely three weeks later, this beautiful big Waved Sphinx Moth had eclosed. Here is a picture of it in the aquarium.

We waited until nighttime then took it outside to release it. Here is the last view we had of it. Well, maybe this moth wasn't a total disappointment.

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