Finding the crayfish

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The other week, we took Eva to visit some friends of the family who live a few miles away. The main inducement was easy access to a quiet portion of the Little Juniata River, and the promise of good crayfish hunting there. Their interest was scientific or aesthetic rather than culinary, though Eva is from a part of the country where crawdads are considered a delicacy. But how do you find creatures that are almost the exact color of the mud they burrow in?

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While the kids honed their crustacean search images, I went hunting for smaller invertebrates. Along the shore, several foot-long bays seethed with tiny rowboats — the aquatic insects known by the somewhat redundant name “water boatmen” (family Corixidae). Their bodies are fully submersible crafts; they have the enviable ability to capture bubbles between the hairs on their bodies and turn them into shiny wetsuits of air.*

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It was a hot and humid late afternoon, and everything seemed a little stunned. In the woods along the river, I found a daddy longlegs resting quietly on a small black cherry leaf, rather like the Little Prince,

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while nearby, a long-legged cranefly took the opposite approach, suspending itself between several sassafras leaves. Clearly, it was a good place to hang out.

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In the adjacent wetland — which was rather parched on account of the drought — a question mark butterfly also seemed intent on doing not very much at all. Of course, it’s the larvae of the species that do most of the work, including locate their proper host plants, elms and nettles. Once they emerge from their chrysalises, life slows down. The females lay eggs hither and yon, as the mood strikes them.

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A white moth floated dead on the surface of a muddy pool. I wondered whether, like the Chinese poet Li Bai, it had drowned while trying to embrace the reflection of the moon. You never know. Back at the river, Eva’s newfound hunting buddy Nathan took a fall that he swore was an accident, and totally unrelated to his previous pleas to be allowed to swim. So much of the hunting impulse seems driven by pure envy of the prey.

*UPDATE: Rebecca Clayton thinks that the bugs in the photo are more likely to be juvenile water striders (see comments). After checking out several reference sources, I’m inclined to agree.

5 Replies to “Finding the crayfish”

  1. Corixidae. They’re abundant and delightful insects–little rowboats indeed. But are you sure? They look rather long-legged for corixids, and that family is most often found in lakes and ponds, rather than in rivers and streams. My first thought was juvenile gerrids (water striders). If you saw them dive, I guess you’d know for sure they’re corixids, and that you’d found something a little uncommon.

    The heteropterans have really claimed the air-water interfaces of the world. Wonderful bugs!

  2. marja-leena – Sorry, no crayfish photos! Actually the hunting was much better here in our mountain creek (different species, hides under rocks), but i wasn’t on most of those expeditions, so again I didn’t get photos. But perhaps i should…

    Rebecca – Keep in mind these were very tiny – i included the twig to give a sense of scale. They did appear to row rather than skate, and just didn’t have the jizz of water striders. However, I gather from this source that juvenile gerrids can have a different form of locomotion from the adults. I didn’t see them dive. So maybe you’re right. You certainly know your heteropterans far better than I ever will!

  3. More excellent photos, & for me more reminders of what, in our respective rural environments, we share & what is so very different. This morning our bathroom was full of crane fly/daddy longlegs, but there’ll be no crayfish in our local waters – not even waterboatmen. And, sadly, butterflies of any persuasion have yet to appear.

  4. Dick – The thing is, if you were to walk around here, you would recognize the great majority of grasses and forbs, especially in disturbed environments like river banks: cow parsley, queen anne’s lace, timothy, orchard grass, yarrow, common plantain, etc.

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