by Carl Strang
Until a couple weeks ago, the grasshoppers that drew my interest belonged to two subfamilies, the band-winged grasshoppers and the stridulating slant-faced grasshoppers. The former have displays in which they rattle their wings in flight (crepitation), and the latter produce sounds by scraping their folded wings with their hind legs (stridulation). There is an additional small subfamily known as the silent slant-faced grasshoppers. Structurally they resemble the stridulating ones in having faces that slant back distinctly from the tips of their heads, but they lack the minute pegs needed to produce the stridulating sounds.
I had encountered one of the members of this non-stridulating subfamily, the clipped-wing grasshopper, a few times in Indiana marshes.
On a recent visit to the Houghton Lake Nature Conservancy site in Marshall County, Indiana, I encountered a cluster of these insects in a little marsh meadow. I started hearing buzzing sounds, and was surprised to find that these were being produced by male clipped-wing grasshoppers.
They were behaving just like band-winged grasshoppers. Sometimes they crepitated when flushed, but they also were producing the rattling sounds in undisturbed display flights. They also can fly without crepitating. Their buzzes had the same loud, crackling quality as, say, a seaside grasshopper from the band-winged subfamily.
Looking back at the literature, I see that Richard Alexander included this subfamily in his list of Michigan singing insects, and so this is no new discovery. I wonder if the few species in this subfamily started out as stridulators that also could crepitate, and over time were selected to emphasize the latter display, then having ruled out stridulation lost the ability to perform it.