A Small Mystery Solved

by Carl Strang

From time to time I have puzzled over a cricket’s trill I have heard in scattered places on the mansion lawn at Mayslake Forest Preserve. I have called them Say’s trigs, because that was closest to the sound of the trill, but two things bothered me: I haven’t found these trigs in mowed lawns elsewhere, and the quality of the sound wasn’t exactly right. Say’s trigs usually are found in dense herbaceous vegetation, or sometimes are up in the foliage of shrubs.

Earlier this week I decided to record that trill for comparison to references. While the mini-disk was recording, it occurred to me that I might take advantage of my shotgun mike’s directionality to try and find the singer. Listening through the headphones eliminated any ventriloquial confusion, and I was able to locate the source within 2 inches. I didn’t see a cricket, but there were two nightcrawler tunnels there.

Further study of the ground revealed that there also are a lot of significant cracks in the soil.

The unimpeded sound I got from close up confirmed that these are indeed Say’s trigs. Something about this lawn, or this population of crickets, has them behaving differently from conspecifics elsewhere. It occurs to me that one possibly significant difference is that there are very few striped ground crickets in the Mayslake lawn, while in practically every other DuPage County lawn they are common. Something about this place apparently causes trigs to replace striped ground crickets. I titled this post “A Small Mystery Solved,” but as so often is the case I have replaced one mystery with another.

The Worms Crawl In, the Worms Crawl Out

by Carl Strang

Yesterday I described my check of garlic mustard seedling survival in study plots established last spring. While carefully removing fallen leaves to expose the seedlings for counting, I found that many of the leaves seemed stuck in the ground. Furthermore, these were in tiny clusters, and instead of the petiole (stem) end, usually the tips were imbedded.

Nightcrawler tunnel 4b

In the above photo you can see how the tip of the oak leaf seems stuck in the ground, and a couple of other leaf petioles radiate out from the same spot. As I removed these leaves, I found that they were in clearly defined holes in the soil.

Nightcrawler tunnel 2b

The holes were uniform in size, and I was finding a lot of them.

Nightcrawler tunnel 1b

I soon realized what must be the case, and sure enough began to spot the ends of nightcrawlers retreating down the holes as I exposed them. Here is one protruding from its hole.

Nightcrawler tunnel 3b

The conclusion seems inescapable that these large earthworms actively are pulling leaves into their tunnels and consuming them. Typically a hole had several leaves, with various proportions of their lengths having gone into the holes and with the ends missing. I hope the photos are making this clear. Certainly the feel of the clustered leaves stuck in the holes as I cleared the study plots was striking. I never would have encountered this if I had not been pursuing the garlic mustard seedling check. Inquiry leads to inquiry.

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