Closing the Book on Prairie Cicadas

by Carl Strang

The prairie cicada is a small (1-inch) insect that occurs in a few remnant prairies in northeast Illinois. Work by Dennis Nyberg and associates at the University of Illinois Chicago has revealed much of what is known about them in the state. I first gained experience with this species a few years ago at the UIC’s Woodworth Prairie in northern Cook County, then quickly discovered them in two DuPage County locations. I expected then that I would find them consistently in prairie remnants, but this has not proven to be the case.

Prairie cicada, June 2017

Recently I finished checking the last of the remnant prairies I know about in the Chicago region, and have not added any more locations to the UIC group’s 8 sites (they also listed 3 sites in downstate counties). I have not found them anywhere in the region’s Indiana or Wisconsin counties.

All the sites are small, so all the populations are small and vulnerable. Mated females do not disperse beyond their little prairie plots, as far as anyone has been able to determine. If the species is to survive in the region, the landholders (mainly forest preserve districts and railroads) will need to continue managing those sites so that the prairies can persist, and prairie cicadas with them.

Advertisements

Closing the Book on Protean Shieldbacks

by Carl Strang

The protean shieldback is the most common native predaceous katydid in the Chicago region. Because of their broad diet, they can develop quickly in the spring. They begin singing in June, the males broadcasting their extended, high-pitched rattles in open woodlands, as well as prairies with at least a little woody vegetation.

Male protean shieldback in singing posture.

At first, they begin to sing in the late afternoon from hidden locations near the ground. When it becomes dark, they climb up onto open perches, often on woody stems. As their season progresses, they begin to sing later, until a few begin at dusk and most wait until dark.

This year I learned that they are more abundant than I had realized. I need the SongFinder, a pitch-lowering electronic device, to hear most of them. With that final lesson, I sought them out in portions of my 22-county Chicago region where I had not found them before. That mission was successful, the final 15 counties resulting in some late-night returns home. At this writing, they still are going strong.

A Mystery Solved: Miogryllus!

by Carl Strang

In 2014 I first heard what sounded to my ear like a singing striped ground cricket, but it seemed too early in the season. It was June 21, at Hoosier Prairie Nature Preserve in Lake County, Indiana. I made a recording, then moved on to the Indiana Kankakee Sands, where I heard it again. Though these sites are a bit south of my DuPage County home, I didn’t hear striped ground crickets in DuPage until July 13. The next year I heard the same odd songs, this time at the Midewin National Tallgrass Prairie, in the middle of Will County, immediately south of DuPage. This was even earlier, on June 10. Again I made a recording. And again, I did not hear striped ground crickets in DuPage until, as it happened, July 13. In 2016 I went down to Midewin on June 28, and heard the same early, striped-ground-cricket like songs. This year, the same story, Midewin, June 23. This time, though, it seemed to me that the songs were not quite right for striped ground crickets. They seemed too precise, too even and strong. Here is a recording I made in the same location on June 28:

I went back and listened to my earlier recordings, reviewed my list of hypothetical singing insect species for the Chicago region, then checked reference recordings of their songs. The early songs did sound different from my recordings of later-season striped ground crickets, an example here:

The odd, early songs seemed to be a match for one of the hypotheticals, the eastern striped cricket, Miogryllus verticalis. Furthermore, references indicated that M. verticalis is an early season species, most abundant in June. I drove back down to Midewin on June 28. Trying to zero in on the singers was very frustrating; they seemed to have a ventriloquial quality. Eventually I flushed out and captured a female cricket near one of the singing mystery males. Looking through the clear plastic cup that held her, I could see that she was indeed an eastern striped cricket. I took a couple photos looking down into the cup. It was well that I did, because when I tried to get her positioned for a shot from the side, she gave me the slip and I was unable to recapture her.

Female eastern striped cricket, dorsal view

She was just a little smaller than a spring field cricket, which species was sharing the grassy meadow where Miogryllus were abundant. This confirms that eastern striped crickets are established in the southwestern portion of the 22-county area I define as the Chicago region. They would seem to represent yet another example of a range extension northward by a singing insect species.

%d bloggers like this: