Roesel’s Katydid Trip, Part 1

by Carl Strang

I reserved some vacation days for last week, to continue probing the range extension of Roesel’s katydid. As detailed in earlier posts, I have been exploring this European species’ geography, beginning in 2007 when I found some in north central Indiana, a state in which they apparently were previously unknown. Since then I have been joined by Scott Namestnik and others, and we have connected Illinois’ Roesel’s, once thought to be a separate population, with the extensive range of the katydids in the Northeast. We still needed to find out how far south they have spread, and also to probe the suspiciously empty lower peninsula of Michigan in Roesel’s range maps.

On Wednesday I drove down to Tippecanoe County and Purdue University, where I went to school. It didn’t take long to find abundant Roesel’s just outside the main campus, at a “new” (keep in mind I was a student there in the 70’s) tennis and cross country athletic facility.

Between the mowed lanes of the cross country course were areas with tall grasses and forbs, ideal Roesel’s habitat.

I heard numbers of singing males, and as I walked along the edge spooked others into jumping. I saw short-winged and intermediate-winged individuals of both genders, but no long-winged katydids.

Here is a short-winged female at the Purdue site.

There has been much speculation in the literature about how the rapid spread of this species would seem to have been done by the long-winged form, rare in the original European range but more common in North America. It is not established whether the age of a local population can be tied to the distribution of wing lengths, however.

That afternoon I went for a bike ride in the northern edge of Tippecanoe County. I heard only a couple Roesel’s along the way, but the wind was very strong, gusting to maybe 30mph, so there may have been many more I didn’t hear.

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