Chasing Coneheads 2: Indiana Dunes

August 15, 2012 at 8:31 am (singing insects)
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by Carl Strang

[Note: Gideon later wrote to share his conclusion that the coneheads we collected were in fact marsh coneheads. The individuals in that population are larger than the ones he was familiar with in Missouri, and the strange gray underside of the cone also was misleading. He later found slender coneheads in another part of their range.] Gideon Ney, Nathan Harness and I reconvened at Indiana Dunes National Lakeshore. We set up camp, but then had to wait out a long afternoon rain wondering if it would stop, if an evening’s search would be any good. The rain stopped an hour before dusk, and we set out prepared to wade through tall wet marsh grasses. We stopped at a corner of the Lakeshore’s Great Marsh, and traded stories as the light faded away. We started hearing the shrill buzzes of coneheads, and began to stalk them. Some of the early ones appeared to be marsh coneheads (Neoconocephalus palustris), which Gideon and Nathan had encountered in Missouri. Then we started catching different ones, and Gideon became increasingly excited as he ticked off characteristics, ultimately concluding that these were the long-sought slender coneheads.

Slender coneheads have medium-sized cones with nearly all the underside darkly pigmented. The Nebraska conehead is similarly marked, but occurs in wooded habitat rather than marsh, and has an interrupted rather than a continuous song.

Most of the ones we found were brown rather than green.

They usually sing head down. This one I disturbed, and he froze after changing position.

Nathan also found plenty of meadow katydids to study back in the lab.

Nathan and Gideon inventory their haul.

They took live katydids back to Missouri, so they can record their songs under controlled conditions in the lab and then get detailed DNA and other biochemical analyses to compare to other conehead species.

Ultimately Gideon hopes to collect slender coneheads from several locations. This species is interesting because it occurs in scattered, separated locations from the Atlantic coast to a site in northwest Illinois. How will its population genetics reflect this indication of a storied evolutionary history?

The night had one concluding chapter, which I’ll share in the next post.

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Chasing Coneheads 1: Illinois Beach State Park

August 14, 2012 at 8:29 am (singing insects)
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by Carl Strang

Last winter I was contacted by Gideon Ney, a graduate student at the University of Missouri in the laboratory led by Johannes Schul. Their focus is the evolutionary relationships among katydids, and members of that research group have published significant analyses of coneheaded katydids, genus Neoconocephalus. One species which they had not yet studied is the slender conehead, Neoconocephalus lyristes, and Gideon found my post in this blog on that species last winter. There I mentioned my interest in finding lyristes, and we corresponded through the succeeding months as we planned our hunt for it. Gideon and another student from that lab, Nathan Harness, who is beginning a study of Orchelimum meadow katydids, came up last week. They started at Chain O’Lakes State Park in Illinois, and I joined them the next day at Illinois Beach State Park. We set up camp, did some scouting, then relaxed in the afternoon.

Gideon and Nathan enjoy the inland sea waters of Lake Michigan.

Coneheads for the most part sing after dark, and we began to drive the roads with windows and ears open as dusk deepened to night. The first conehead we found was the sword-bearing conehead, a common species of dry meadows.

The face of a sword-bearing conehead. The English name for the group refers to the structure protruding from the top of the head between the eyes. In this species the cone has a crescent-shaped black mark near the tip.

The sword-bearing conehead is named for the female’s ovipositor. Gideon caught one and held it for my photo.

Here you can see that the ovipositor extends slightly beyond the wings.

Most of the coneheads we found had unornamented cones like those of the robust conehead, which I found at Kankakee Sands last month. However, the song was not nearly as loud, and the tentative conclusion was that these belonged to a different species, the false robust conehead. We heard a good variety of singing insects, but no slender coneheads, and so made plans to shift to Indiana Dunes National Lakeshore the next day (to be continued).

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