by Carl Strang
The third goal of my Upper Peninsula trip last week was to study the singing insects there. Compared to northern Illinois, the singing insect fauna was very limited. At night the campground at Tahquamenon Falls State Park was quiet, except for the amazing snoring of one of my neighbors, thankfully only for one night. During the day the principal singing insect in the forest was the dog-day cicada.
Open areas such as Whitefish Point had more to offer. I was especially pleased to find that gray ground crickets are common there. Like all ground crickets these stayed well hidden. Here is typical habitat.
This species is known from dunes areas around southern Lake Michigan, but the only time I was at Illinois Beach State Park listening for them was a windy day and I could not hear them clearly. At Whitefish Point I easily distinguished their song. Though the trills seem composed of discrete notes like those of Allard’s ground cricket, they are at least three times faster (Allard’s were there as well, making comparison easy). Also, the trills were not continuous but rather were interrupted by brief pauses that were spaced regularly in some individuals but at varying intervals in others. In addition to Allard’s, familiar crickets at Whitefish Point were fall field crickets and Carolina ground crickets.
Whitefish Point also was home to two singing grasshoppers that represented the two forms of grasshopper song production. One of them was a crepitating species like Illinois’ greenstriped grasshopper. My references point to the clearwinged grasshopper, Camnula pellucida, as the identification, though I am not certain.
In the photo the male is on the left. Crepitation is sound production by the rattling or snapping of the wings in flight. In this species the rattle is much louder than that of the greenstriped grasshopper. Clearwinged grasshoppers occupied the more open dunes areas. The other form of sound production is called stridulation. A common grasshopper that stayed close to woody plants at Whitefish Point produced loud “zuzz-zuzz-zuzz” sounds with this method. My best stab at identification is Thomas’s broad-winged grasshopper, Chloealtis abdominalis.
The black areas on the sides of the pronotum seem to point to that species. Another photo, taken just as the grasshopper turned to put some distance between itself and my camera, shows that from behind the legs have a lot of red on them.
In stridulation, both legs are lifted and lowered at once, and rows of pegs on them rub against the folded wings to produce the sound.
I also found broad-winged bush katydids at Whitefish Point, but I will hold that discussion for a later time.