by Carl Strang
Recently I shared the story of a tree cricket that I suspected may be a prairie tree cricket. Last week I caught a second one which confirmed the identification, at least as far as I can tell.
Like the first, he was pale, and his extremities were brown rather than the black of a black-horned or Forbes’s tree cricket.
The critical feature is the spotting on the first two antenna segments.
I was concerned that the pixilation in the photos might be distorting the appearance of spacing between the spots on the second segment, so I took the added step of examining them through the magnifying glass. The spaces were indeed being exaggerated by the camera. This further supports the case for prairie tree cricket.
So now I have the impression that all four species in the nigricornis group of meadow-dwelling tree crickets are present (I have found the four-spotted tree cricket in a few locations), and all may be common, in northeast Illinois. The prairie tree cricket, once a western species, has spread east thanks to agricultural practice. After catching the subject of this post I have had a devil of a time trying to get more (they seem to be staying close to the ground for warmth), so I may not make more progress in quantifying the relative numbers of the species this year. Unfortunately the pulse rates of prairie and black-horned tree cricket songs are nearly identical across the range of temperatures in which they sing. Otherwise I could do the survey entirely with recordings. The four-spotted seems to prefer grasses, but song perches for the other three are goldenrods, asters and even woody plants, so there is little to distinguish them in habitat preference. As for monitoring practice, it looks like this will simply have to be a category “nigricornis group” rather than a count of the separate species.