Return to Illinois Beach

by Carl Strang

Recent success in finding new species of sand-dwelling grasshoppers brought me back to Illinois Beach State Park in hope of continuing the run. On the beach I confirmed the presence of seaside grasshoppers, but was startled at the color contrast between them and the members of their species at Indiana Dunes National Lakeshore

Here is one of the Illinois Beach State Park hoppers.

Here is one of the Illinois Beach State Park hoppers.

And here is one from Indiana Dunes. Same species, different substrate, a nice study in natural selection.

And here is one from Indiana Dunes. Same species, different substrate, a nice study in natural selection.

Behind the foredune is a flat in which I found three species of singing grasshoppers, all in the band-winged grasshopper subfamily. The pattern continued of a larger species, a smaller one, with a couple Carolina grasshoppers thrown in for good measure.

The larger grasshopper was the by now familiar mottled sand grasshopper. These, like the seaside grasshoppers, were browner than their conspecifics in Indiana.

The larger grasshopper was the by now familiar mottled sand grasshopper. These, like the seaside grasshoppers, were browner than their conspecifics in Indiana.

The small band-winged grasshopper at first made me think of the longhorn band-winged grasshopper.

The head protrudes above the pronotum, the size is the same, and the antennae look long.

The head protrudes above the pronotum, the size is the same, and the antennae look long.

However, in place of the bright red patch at the base of the hind wing, here it is transparent. The hind tibia pattern also is different. Both areas are hidden in the resting insect, and so not subject to selection pressure by predators.

This was a new species for me, the Kiowa rangeland grasshopper.

This was a new species for me, the Kiowa rangeland grasshopper.

A little farther back from the shore, where the first trees appear, other insects may be found.

This is Dawson’s grasshopper, not a singing species (as you might guess from the dinky wings).

This is Dawson’s grasshopper, not a singing species (as you might guess from the dinky wings).

So far the meadow tree crickets I have found at Illinois Beach all have been four-spotteds. This one, too, as evidenced by the shapes of spots on the basal antenna segments.

So far the meadow tree crickets I have found at Illinois Beach all have been four-spotteds. This one, too, as evidenced by the shapes of spots on the basal antenna segments.

Finally, in the savanna zone, the dominant singing grasshopper is Boll’s grasshopper.

Boll’s is in the same genus, Spharagemon, as the mottled sand grasshopper.

Boll’s is in the same genus, Spharagemon, as the mottled sand grasshopper.

Like the mottled sand grasshopper, Boll’s grasshopper has bright yellow in the hind wings.

Like the mottled sand grasshopper, Boll’s grasshopper has bright yellow in the hind wings.

 

The easiest way to tell the two apart is to look at the angle of the back top edge of the pronotum (thorax shield). In Boll’s, here, the angle is more than 90 degrees. In the collared sand grasshopper it is acute.

The easiest way to tell the two apart is to look at the angle of the back top edge of the pronotum (thorax shield). In Boll’s, here, the angle is more than 90 degrees. In the mottled sand grasshopper it is acute.

A final treat from that portion of my exploration was a big, beautiful female bird grasshopper laying eggs in the sand of the trail.

The non-singing grasshoppers of genus Schistocerca can be difficult to tell apart. I decided this one was S. alutacea, the leather-colored bird grasshopper.

The non-singing grasshoppers of genus Schistocerca can be difficult to tell apart. I decided this one was S. alutacea, the leather-colored bird grasshopper.

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