Kankakee Sands is a Nature Conservancy site in Newton County, Indiana. Except for the early-season bioblitz there a few years ago, my visits have been in the daytime. Last week I made a nighttime trip to Kankakee Sands. This netted several new species observations for the county as well as the site, the best of which was a grasshopper I had not encountered before.
The handsome grasshopper is well named. A spindly little guy, he was rather jumpy after I caught him in the grasses and released him on the gravel parking lot.
All of that was incidental to my main goal, however, which was to continue my collaboration with Gideon Ney of the University of Missouri. Gideon’s lab, led by Johannes Schul, is working out the evolutionary history and relationships of the conehead katydids, genus Neoconocephalus. Two of them, the robust conehead and the false robust conehead, are sibling species reliably separated mainly by differences in their songs.
Robust conehead…or is it?
I stopped at several locations, recording singing males and then trying to catch them. I need practice. They were quick to stop singing as I approached. Ultimately I was able to accumulate 12 recordings, catching the males producing 6 of them.
Here they are, ready to be packed for overnight shipping along with the recordings.
A couple of the songs seemed different to my ear, so I am hopeful that the effort will result in a mix of the two species, and an education on what to look for in sonographs of the recordings so I don’t have to capture them in the other counties of my survey region.
When I mention the coneheads to people unfamiliar with singing insects, the response almost always is a smile. I have to agree: one reason why the slightly musical conehead is my favorite singing insect (at the moment) is that name. Our coneheads are all katydids in genus Neoconocephalus. I have been fortunate to spend some time in the field with Gideon Ney, a Ph.D. student at the University of Missouri who is working out of a lab led by Johannes Schul that has done a lot of work with the evolution of that group. Thanks to Gideon I am aware of two species of coneheads that are not supposed to occur as far north as the Chicago region, but turn out to be at least locally common. Today I share recordings of the 6 documented species in the region. Warning: these are not delightfully musical or even (despite the name mentioned above) slightly so. We’ll ease into it with one that is somewhat pleasant to hear: the sword-bearing conehead. Its song:
That recording was made in a grassy upland meadow, typical habitat for the species, but close enough to the edge of the woods that a few common true katydids came through loud and clear. The conehead’s song is the continuous string of rasping ticks or brief buzzes. It has been compared to the sound of a sewing machine or a distant steam locomotive.
The sword-bearing conehead is named for the very long, straight ovipositor on the female.
The next species also has a discontinuous song. The slightly musical conehead was given that name because W.T. Davis, who described it, thought it was not very loud (though he later changed his mind on that point).
The rasping sounds are easy for me to hear even with my older ears. This is a wetland species, and the males typically sing in unison.
The coneheads are named for the structure on the tip of the head, especially prominent in the slightly musical conehead.
Another species with an interrupted song is the Nebraska conehead.
The buzzes are not as rough as in the previous species, and will be heard in bushy undergrowth of woodlands, or sometimes bushes out in fields. In the southern part of the Chicago region, where the species is more common, the males sometimes sing in unison as well.
Male coneheads often sing head down. It has been speculated that the cone helps them penetrate the vegetation beneath when they are disturbed and drop to hide. Nebraska coneheads have medium sized, all black cone undersides.
The remaining 3 species all have continuous buzzes. Most common region-wide is the round-tipped conehead, a katydid of meadows and roadsides.
Listen for a crackling sound in this continuous buzz.
Here the cone is short, round, and has a small black area near the tip.
Next is the marsh conehead, which so far has turned up only in the marshes of the Indiana Dunes parks.
The sound resembles that of the round-tipped, but comes from a wetland rather than dry upland habitat.
The cone of the marsh conehead may be all green as in this female, or show variable darkness of color.
For the grand finale, here is the very loud song of the robust conehead:
This can be so loud as to be painful to the ears. It carries for long distances, as you may imagine, and is easy to hear from a car at any speed.
The robust conehead’s cone is unmarked and proportionately short. Any conehead species can come in green or brown.
The robust conehead is most abundant in areas with dry sandy soils. Its habitat range is fairly broad, from open woodlands to prairies to corn fields.
There are at least two other species which are supposed to occur in the region, but which I have not found. Perhaps next winter I will have recordings of false robust coneheads and slender coneheads to share.
Last year, while conducting an evening survey drive to map fall field cricket distributions in my home county of DuPage in Illinois, I was passing through Springbrook Prairie Forest Preserve when I thought I heard a couple robust coneheads singing.
Male robust conehead in singing posture, Newton County, Indiana
This was surprising, and I wasn’t able to follow up in 2012, but it was on this year’s research checklist, and on Monday evening I heard them again in the same location. I found a place to park, and to make a long story short was able to confirm my suspicion (a later sonograph analysis of the recording I made will determine whether this was a robust conehead or, less likely given the loudness of the song, a false robust conehead).
This discovery was surprising because in general I have been finding them, as researchers in past decades also have noted, mainly in areas with sandy soils. No such soils exist outside children’s playgrounds in DuPage. On the other hand, no lesser a light than Richard Alexander listed DuPage County as a place where he had found the species a few decades ago. This is not a simple matter of latitude, as robust coneheads are abundant in sandy Lake County, Illinois, to the north. This species joins the tinkling ground cricket and spring trig as species that I have found in the county, but only in extremely small numbers in one or two places. DuPage County, out of all the 22 counties in my regional survey, is the one I have surveyed most thoroughly, and for nearly 8 full seasons. These few locally rare species are indicators that there probably will be holes in my distributional records for all counties, and so these will need to be judged accordingly. I will need to continue searching for new sites through the seasons and years, as long as I am able to do so.
The traveling singing insect survey took me to Kankakee County one day recently. It proved to be primarily an agricultural county, and I spent much of the day finding places to which I will not need to return. The county’s gem is Kankakee River State Park, and all the singing insects I had found elsewhere in the county also were there, a total of 15 species.
An attractive scene at Kankakee River State Park.
These included the first robust conehead and northern dusk-singing cicadas of the year. My past experience with that cicada was occasional songs during the day, from late morning through dusk, but those in the state park lived up to their name. None sang until about 15 minutes before sunset, but then many were singing. The robust conehead was a through-the-car-window identification. It was singing in an upland meadow, and there was no place to pull off. The only other possibility for that loud droning song after dark is the false robust conehead, but until I have confirmed the presence of the latter this far north I am inclined to go with robustus. At some point I will make a series of recordings to see if I can discover the more southern of these two sibling species in our area.
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).
Nature Inquiries 