Making a Case 2: Prairie Meadow Katydid

by Carl Strang

After more than ten years of study, I still have not found several species of singing insects that historically were known in the Chicago region. One of these was the prairie meadow katydid, one of the smaller members of its group. On August 16, Wendy Partridge and I were checking out the bike trail near the nature center at Illinois Beach State Park. Through the SongFinder, which allows me to hear high pitches, I heard faint rapid ticking sounds which, when heard from a closer position, resolved into brief buzzes. They were mechanical and katydid-like rather than cricket-like in quality, and didn’t match anything I had heard before. Wendy, with her unusually good hearing, barely could pick them up. Later, checking reference recordings, I decided they fit the song of the prairie meadow katydid. They were not in the habitat I would expect, however, being in dense vegetation where grasses were mixed with woody plants and forbs, generally shaded. That katydid species has been known to occur in that park, however.

Then on September 27 I caught and photographed a small female meadow katydid in a relatively dry portion of the Gensburg Prairie in Cook County.

Posterior portion of the Gensburg Prairie female.

Posterior portion of the Gensburg Prairie female.

Her color didn’t seem quite right for a short-winged meadow katydid, which is a common species at that site especially in the wetter portions. Studying the photos, and looking back at references, I have decided that she was a prairie meadow katydid. Along the way I looked back at all my photos of short-winged meadow katydids, and found two other individuals that met at least some of the criteria for prairie meadow katydid, one in 2011 at Mayslake Forest Preserve, and one in 2014 in the savanna woodland at Illinois Beach State Park.

The Mayslake female

The Mayslake female

The Illinois Beach State Park female

The Illinois Beach State Park female

All three have curved ovipositors that are slenderer in proportion than in a typical short-winged meadow katydid.

Typical female short-winged meadow katydid

Typical female short-winged meadow katydid

All three also have femoral patterns in which there is a lengthwise pair of lines, as in the short-winged, but have ladders of narrow crossbars rather than being clear between them as in typical short-winged. There is enough overlap in body length, according to references, that it is not a consideration in comparing those two species. The ovipositors are too short, and the femur patterns wrong, for straight-lanced meadow katydid to be a consideration. The Mayslake female is different from the other two individuals in three possibly significant ways: the femoral ground color is green rather than brown or tan, the wings are much longer, and the front of the head does not appear to rise so much (this last being a difference mentioned by W.S. Blatchley in his classic Orthoptera of Northeastern North America, which gives unusually detailed descriptions of species).

Anterior portion of the Gensburg Prairie female. Note the abrupt rise of the tip of the head when viewed from the side.

Anterior portion of the Gensburg Prairie female. Note the abrupt rise of the tip of the head when viewed from the side.

Dorsal view of the Gensburg Prairie female. Blatchley describes the wings of prairie females as covering only one-fourth of the abdomen, two-thirds in short-winged females. Furthermore, the tip of the head, when viewed from above, is relatively wide after an inward bending of its sides, expected from Blatchley’s description.

Dorsal view of the Gensburg Prairie female. Blatchley describes the wings of prairie females as covering only one-fourth of the abdomen, two-thirds in short-winged females. Furthermore, the tip of the head, when viewed from above, is relatively wide after an inward bending of its sides, expected from Blatchley’s description.

Compare this common meadow katydid, with its relatively narrow and straight-sided tip of the head, to the previous.

Compare this short-winged meadow katydid, with its relatively narrow and straight-sided tip of the head, to the previous.

 

Side view of the same male as in the previous photo. Again, note the lack of a rise in the top of the head profile.

Side view of the same male as in the previous photo. Again, note the lack of a rise in the top of the head profile.

Blatchley also believed that prairie meadow katydids occur only in “raw prairie,” a description which applies to Gensburg and Illinois Beach but not to Mayslake. I am inclined to regard the Mayslake individual as an anomalous short-winged meadow katydid, but pending study of museum specimens, am naming the other two prairie meadow katydids.

Seeking All the Answers

by Carl Strang

OK, the title is way too big for the subject of this post, but it’s not entirely wrong. As I complete my 6th season of singing insects study, there remain several species that range maps indicate should be in northeastern Illinois, but that I have yet to find. The past couple of seasons I have been going to places that match habitat descriptions for missing species, and I have added techniques to my repertoire. This has filled some of the gaps, for instance with the sphagnum ground crickets I found at Volo Bog. Now I am beginning to go to the source data on which those maps are built. Today’s example is the prairie meadow katydid.

This is the map for that species in the Singing Insects of North America website (SINA). It appears in the site’s page for the prairie meadow katydid, and as you can see it indicates a range that encompasses northeastern Illinois. SINA is the most comprehensive source of information about our singing insects. Created by Tom Walker, SINA is very clear and open about its methods. The maps are constructed by a computer program from a database you can download. The information for each dot on the map is in that database, and that is what I studied to further my search for the prairie meadow katydid.

A couple of things stood out as I focused on the Illinois and Indiana records for this species. First, all but one of the Illinois records are older than 1940. The same is true for all but four of the Indiana records. Things change, and I wonder if these data still are valid. Second, all the Illinois records appear to be from areas with sandy soil, as are at least most of the ones from northern Indiana. I am not so familiar with the southern Indiana sites.

Nearly all my field work has been in DuPage County, which lacks sandy soils. I conclude that I should return to places I began to visit this year that have such soils, and see if I can find this katydid there. Since it is one of the smaller meadow katydids, I will need to use the SongFinder to hear it, and may need to get permits to do some sweep sampling in order to see it.

Stripes

by Carl Strang

Identifying species of small meadow katydids (genus Conocephalus), especially nymphs, can be challenging. Most adults are readily sorted out, especially males if you can get a good look at the cerci or claspers at the tips of their abdomens.  Females are trickier, but their ovipositors often allow distinctions to be made. I’ve decided to take a shotgun approach in my survey at Mayslake Forest Preserve, sweep sampling on a weekly basis and taking photos of as many individuals as I can. Last week I noticed something that is potentially helpful.

This is an unambiguous male short-winged meadow katydid. Cerci are right, lots of orange color around the abdomen tip, short wings, small size.

As I compared my many photos, I found that the color pattern on the sides of the hind femurs drew my eye. Notice the band of clear green color bounded by brown stripes on either side. Here’s a female, again clearly a short-winged.

Though she may be an instar short of adulthood, this one has the ovipositor of a short-winged.

Again the color pattern on the femur appears. I did an Internet search, and except for some photos from Texas, short-winged meadow katydids show this striping pattern across eastern North America. Then I began to compare other species. I started with another familiar one, the slender meadow katydid.

This male I photographed last year has clear green femurs, without the stripes.

Again an Internet and reference book search showed consistently clear green femurs on this species. However, I was surprised to find that a female I had identified a couple years ago as a slender meadow katydid had the femur stripes.

The long wings fooled me. The ovipositor actually rules out slender meadow katydid. This was a rare individual short-winged meadow katydid with long wings.

Next I turned to two species I have been seeking, which could overlap with the short-winged’s habitat. Straight-lanced meadow katydids in references and Internet photos lack the short-winged’s stripe pattern, instead often showing a diffuse blackish zone down that face of the femur. I went to photos of females I tentatively had identified as that species last year.

This one not only has an ovipositor much longer than the femur length, and lacks orange at the abdomen tip, but shows a femur color pattern different from the short-wingeds’ and consistent with straight-lanced reference photos. In fact it appears that the diffuse black zone is the same as the upper dark stripe on the short-winged, but differing in color and not sharply bounded. The lower stripe is there as well, but just as a trace of a line. I believe this individual may indeed have been a straight-lanced meadow katydid.

Others prove, on closer inspection, in fact to have been short-wingeds.

This young nymph has an ovipositor marginally longer than the femur, but has an instar or two to go until maturity and looks awfully orange around the abdomen. The femur color pattern clearly ties it to short-wingeds, and I think that is where this insect belongs.

The other species I need to sort out is the prairie meadow katydid. Few photos of this one are out there. In some there is no stripe pattern like the short-winged’s, in some there is a hint of one. For now I will need to focus on cerci (straighter, more pointed and with distinctly longer teeth than the short-winged male’s) and ovipositors (proportionately more curved than the short-winged female’s). I am encouraged, however, to continue looking for details of color pattern that might provide short-cuts to field identification at least in regional or local populations.

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