Search for Variegated Ground Cricket

by Carl Strang

The variegated ground cricket, Neonemobius variegatus, has been an intriguing presence on the “possibles” list of northeastern Illinois singing insects. Though its range map at the Singing Insects of North America website (SINA) includes our region, essentially nothing else about the species was there until the recent addition of a photo. Last year I stumbled across some information on the Internet that partly explained the lack of information.

The recognition of this species began as a Nebraska specimen named Cyrtoxyphus variegatus. Hebard in his revision of ground crickets (1913. Proc. Acad. Nat. Sci. Philadelphia 65:394-492) placed it in subgenus Neonemobius and re-named it Nemobius bruneri. He mentioned that it occurred in Kansas and Indiana as well, and described it as having a striking dotted speckled appearance. Hebard identified specimens collected from pebbles and stones along the Oletangy River at Columbus, Ohio, but in his 1934 monograph on Illinois Orthoptera placed all its locations in the southern part of our state. Another publication, reviewing North Carolina singing insects, describes a similar habitat (gravel beds and sandy stream banks, not in thick woods), mentions it is a late summer and fall species, and describes its song as being a continuous unbroken trill, high pitched and weak, lacking pulses and produced day and night. In 2010 I sought it without success in the rocky edges of Sawmill Creek at Waterfall Glen Forest Preserve.

The map at SINA suggested that they are in Ogle County, so I headed to the Rock River on Tuesday. Among my stops was this one at Castle Rock State Park.

This was fractured stone rather than gravel, though there was plenty of sand mixed in along the shore.

The picture in my mind of variegated ground cricket habitat was matched perfectly by this site at Oregon.

Nice round gravel covers a large area of shore.

In these locations I listened with my ears alone and with the SongFinder, walked over the entire area scanning carefully, kicked gravel, turned over lots of stones.

In my mind they should be here.

Nothing. The optimist in me describes this trip as successful. I succeeded in discovering one way not to find variegated ground crickets. I’m not sure what my next step will be. I plan to head down toward the Kankakee River in the next week or two. Maybe I’ll find them there.

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