Protean Shieldback

by Carl Strang

Yesterday as I rode my bike through Blackwell Forest Preserve I heard my first protean shieldback songs of the year. The scientific name of this katydid is as musical as its common name: Atlanticus testaceus.

Atlanticus female 2b

This is our only common native species of predaceous katydid. We also have a common non-native species, Roesel’s katydid, which I will feature soon. They are called predaceous katydids, but the main point is that they draw their nutrients from animal, rather than plant foods. They are scavengers as well as predators. Protean shieldbacks were very abundant two springs ago, during the periodical cicada emergence. In part this is because they fed well by scavenging dead cicadas, but they probably also benefited from their predators being sated on cicadas. Their carnivorous diet allows them to mature faster than their vegetarian relatives, and so they are the earliest katydids to sing each year (though the common meadow katydid is not far behind).

Protean shieldbacks don’t usually venture far from woody plants, and are fairly common in woodlands, woodland edges and brushy areas in DuPage County. I have found them in grassy fields with dense tall herbaceous plants, too. The males sing from late afternoon until well after dark. Their song is a soft rattling buzz, moderately high pitched, lasting 1-6 seconds. The sound quality is like a stage whisper, I would render it a rapid “thithithith…” about twice as fast as I can produce vocally. For a sound recording, go here  or here . Their season isn’t long; they will be done by mid-July.

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