by Carl Strang
At mid-day on Friday, a tree cricket sang from a Canada goldenrod plant near the eastern edge of Mayslake Forest Preserve.
At this point in the season, the long-trilling meadow-dwelling tree crickets are mainly members of the sibling species pair of black-horned tree cricket and Forbes’s tree cricket. The two species cannot be distinguished except through an analysis of their recorded songs. The critical feature of the song, the pulse rate, varies with temperature, and in the field the temperature can vary significantly with microsite at this time of year. So, I caught him and installed him in a cage. Back home, in the quiet of the evening, he began to sing and I got my recording.
The next day I wanted good photos for documentary purposes. I put the cricket in a jar, and the jar in the freezer for 10 minutes. This immobilized the little guy long enough for me to get photos.
The cricket’s adventure was nearly complete. I had a public night hike Saturday night, and I took him in a jar, releasing him with an explanation of his story and the reason I put him through it.
It was only later, when I studied the photos closely, that I began to have some doubts. The heavy, close-together markings correspond more closely to those of a third species, the prairie tree cricket, which I had been seeking but not found. The literature and on-line information seem to suggest that, nevertheless, this could be a black-horned/Forbes’s. The critical question seems to be, how wide is the space between the two bars on the second antennal segment? If it is less than a third the width of the inner bar, then this is a prairie tree cricket. If more, it’s a black-horned/Forbes’s. As best I can tell, it is very close to this critical width. I will continue to pursue the question for this individual, but all of these species show some variability, and my best response is to find more crickets in Mayslake’s meadows, and see what they tell me.