Sound Ideas: Gray Ground Cricket

by Carl Strang

In the vegetation that grows just behind the beaches around the western Great Lakes you may hear a very rapid, high-pitched trilling sound, as in this recording I made at Whitefish Point (on the north side of the tip of Michigan’s Upper Peninsula) on September 16, 2009:

The area where the previous recording was made.

The area where the previous recording was made.

This interrupted trill is identical to the reference recording for the gray ground cricket on the Singing Insects of North America website. Indeed, this species is expected in open, sandy soil habitats. The only other ground cricket song I have heard that is close to this is that of the sphagnum ground cricket, which is restricted to sphagnum bogs and could not survive on sand. Allard’s ground cricket, when it occurs with the gray ground cricket, has a distinctly slower song.

The challenge for me with this species has been two-fold. First, I have never seen one. Second, I am pretty sure they occur inland as well. Here is a recording from Braidwood Dunes, a Will County Forest Preserve, September 7, 2011:

At the time I noted that there were pauses, but enough crickets were singing simultaneously that these are difficult to pick out in the recording. I have heard, and sometimes recorded, this same song in other inland locations in Kendall, Marshall and Fulton Counties. Sometimes the pauses are infrequent or nearly absent, but the songs all have a peak frequency of 8-8.5 kHz, and share similar patterns of amplitude irregularity in their sonographs. I am not aware of any other cricket that could occur in dry soils with a song like this. Furthermore, there are some mentions of inland gray ground crickets in the literature, and some authors refer to the trill as continuous. So, mainly by process of elimination I have decided to refer to all these crickets as gray ground crickets for now, but with a higher priority of catching one, particularly at one of the inland sites, for confirmation.

Hypothetical Cicadas and Grasshoppers

by Carl Strang

Thanks to two publications, one very new and one very old, I have been able to fill out my list of singing insects that may occur in the Chicago region by adding possible cicada and grasshopper species. The new reference is a monograph published last year by the Entomological Society of America, The Cicadas (Hemiptera: Cicadoidea: Cicadidae) of North America North of Mexico, by Allen F. Sanborn and Maxine S. Heath. There is not a lot of natural history information in it, as its focus is on sorting out species and their relationships, but it is complete in its species coverage and at least outlines the range for each. It allowed me to add three possible cicadas to my list. Two of them are tallgrass prairie specialists that are known in Illinois but may not occur this far north: the common grass cicada (Cicadetta calliope), a tiny early season species, and the bush cicada (Tibicen dorsatus), a late season species. The third added cicada, Walker’s cicada (Tibicen pronotalis), is a large insect of woodlands along streams.

The old reference is W.S. Blatchley’s Orthoptera of Northeastern America with Especial Reference to the Faunas, of Indiana and Florida. This one was published back in 1920, and is available as a 2012 reprint by the Forgotten Books company. The text is generally readable, but somewhat faint. The taxonomy and nomenclature for the grasshoppers have been remarkably stable over time, and most scientific names haven’t changed. I was able to make the necessary updates by referring to the most recent popular guide to grasshoppers, katydids and crickets by Capinera, Scott, and Walker. Blatchley’s book contains considerable natural history information, and is reminiscent of the Bent’s Life Histories of Birds in its style.

There are two subfamilies of singing grasshoppers. The stridulating slantfaced grasshoppers, subfamily Gomphocerinae, sing while perched or resting on the ground, lifting and lowering their back legs to rub them against the wings, producing a rapid zuzz-zuzz-zuzz sound that is distinct from other insect songs, but to my ear this stridulation seems much the same in different species. The only one for which I have a photograph is a northern species.

Thomas’s broad-winged grasshopper at Whitefish Point on the Upper Peninsula of Michigan.

Thomas’s broad-winged grasshopper at Whitefish Point on the Upper Peninsula of Michigan.

That grasshopper does not occur as far south as our area, but another member of its genus, the sprinkled broad-winged grasshopper (Chloealtis conspersa) is one I’ll listen for, along with 7 other candidates in this subfamily. Though their songs probably are much the same, their habitats and details of their appearance are different.

The other singing subfamily of grasshoppers is Oedipodinae, the band-winged grasshoppers. These produce their sounds in a different way, crepitation, by rattling or rubbing together their wings in flight. The potential additions to the local list number a dozen species. One of these also was prominent at Whitefish Point.

A pair of clear-winged grasshoppers, Camnula pellucida

A pair of clear-winged grasshoppers, Camnula pellucida

The literature suggests more variation in the sounds produced by the crepitation method, but these grasshoppers are flying when they sing, and so should be easier to locate.

Miscellaneous U.P. Notes

by Carl Strang

In this final chapter of my Michigan vacation account, I will bring together assorted observations of other animals and sights. None of this truly counts as inquiry, except that travel and the exposure it gives us to new places leads us to make comparisons with our familiar environment. Such comparisons often lead to questions and inquiries on down the line.

At Muskallonge Lake, after completing my investigation at the beach, I went for a walk along the state park’s trails.

Muskallonge Lake trail b

There were spectacular views of Lake Superior from elevated points, and flocks of migrating songbirds to investigate.

Tahquamenon Falls State Park is named for various waterfalls along the Tahquamenon River. Especially spectacular are the upper falls.

Tahquamenon Falls upper 1b

After a summer in which I made good progress in my knowledge of Illinois bumblebees, I was interested to find that in that part of the U.P., as back home, only one common species of short-tongued, generalist bumblebee is active at this point in the season. Here it’s Bombus impatiens; at the tip of the U.P. it was the beautifully marked Bombus ternarius.

Bombus ternarius 2b

B. ternarius is a northern species that does not extend its range down to Illinois.

One of the more charismatic birds that one hears and, sometimes, sees in the north woods is the pileated woodpecker. Here is a tree that has been well worked by that species.

Pileated work b

Beauty on a smaller scale, which provided a reminder of the season in transition, took the form of this aspen leaf lying on a trail.

Aspen leaf 1b

I spent most of my time at Whitefish Point. Here is a small scene I found especially compelling.

Whitefish Point 7b

As I walked out from the point to the parking lot for the final time, I found an enchanting little animal crossing the trail.

Smooth green snake 3b

Smooth green snakes occur in many places, but are so well camouflaged that we seldom have the good fortune to see them.

On my final morning at the Tahquamenon Falls campground, I found that a large number of moths had been drawn to the restroom building’s lights.

Nepytia canosaria 1b

These were nearly all males of the same species, emerging all at once.

Nepytia canosaria 3b

Nepytia canosaria, the false hemlock looper moth, is a common northern species whose larvae feed on a wide range of coniferous species including firs, hemlock, pines and spruces.

Singing Insects at Whitefish Point

by Carl Strang

The third goal of my Upper Peninsula trip last week was to study the singing insects there. Compared to northern Illinois, the singing insect fauna was very limited. At night the campground at Tahquamenon Falls State Park was quiet, except for the amazing snoring of one of my neighbors, thankfully only for one night. During the day the principal singing insect in the forest was the dog-day cicada.

Open areas such as Whitefish Point had more to offer. I was especially pleased to find that gray ground crickets are common there. Like all ground crickets these stayed well hidden. Here is typical habitat.

Gray ground cricket habitat b

This species is known from dunes areas around southern Lake Michigan, but the only time I was at Illinois Beach State Park listening for them was a windy day and I could not hear them clearly. At Whitefish Point I easily distinguished their song. Though the trills seem composed of discrete notes like those of Allard’s ground cricket, they are at least three times faster (Allard’s were there as well, making comparison easy). Also, the trills were not continuous but rather were interrupted by brief pauses that were spaced regularly in some individuals but at varying intervals in others. In addition to Allard’s, familiar crickets at Whitefish Point were fall field crickets and Carolina ground crickets.

Whitefish Point also was home to two singing grasshoppers that represented the two forms of grasshopper song production. One of them was a crepitating species like Illinois’ greenstriped grasshopper. My references point to the clearwinged grasshopper, Camnula pellucida, as the identification, though I am not certain.

Clearwinged grasshopper 2b

In the photo the male is on the left. Crepitation is sound production by the rattling or snapping of the wings in flight. In this species the rattle is much louder than that of the greenstriped grasshopper. Clearwinged grasshoppers occupied the more open dunes areas. The other form of sound production is called stridulation. A common grasshopper that stayed close to woody plants at Whitefish Point produced loud “zuzz-zuzz-zuzz” sounds with this method. My best stab at identification is Thomas’s broad-winged grasshopper, Chloealtis abdominalis.

Thomas's broad-winged grasshopper 3b

The black areas on the sides of the pronotum seem to point to that species. Another photo, taken just as the grasshopper turned to put some distance between itself and my camera, shows that from behind the legs have a lot of red on them.

Thomas's broad-winged grasshopper 5b

In stridulation, both legs are lifted and lowered at once, and rows of pegs on them rub against the folded wings to produce the sound.

I also found broad-winged bush katydids at Whitefish Point, but I will hold that discussion for a later time.

Green Bay Lobe

by Carl Strang

A second goal of my trip to Michigan’s Upper Peninsula last week was to investigate further the stones left by the most recent continental glacier. As I outlined in an earlier series of posts, my vacation trip last year was a pilgrimage into Canada to trace the route  of the Lake Michigan lobe of that glacier, which is responsible for the deposits which cover the land in the northeast corner of Illinois. The turquoise line in the map below follows the route I think that lobe followed.

Glacial lobe map b

I studied the various categories of bedrock northeast of Lake Superior, chunks of which were picked up by the glacier and now reside where that powerful river of ice left them when it melted away. I found that there appeared to be commonalities in the stones left as drift along the Lake Michigan lobe’s route in Canada, on the Upper Peninsula of Michigan, and in northeast Illinois. Stones northwest of that route in Canada seemed different, and I was curious to see if those differences might hold farther south along the route of the Green Bay lobe, which is the one immediately west of the Lake Michigan lobe. I chose to visit Muskallonge Lake State Park, on the U.P.’s north shore, approximately in the center of the Green Bay lobe’s route, so that I could compare the beach stones there to those at Whitefish Point, at the U.P.’s tip, which was on the route of the Lake Michigan lobe.

Muskallonge Lake sign b

It was a foggy day, but a few people were there. Some were gathering stones, a practice which might bias the results.

Muskallonge Lake beach 5b

For instance, it seemed to me that beach stones at Canada’s Agawa Bay, along the Green Bay route, included an unusual number of red granites and greenstones. If these are selectively removed by visitors, the remaining stones might not represent what had been there originally. I certainly found greenstones, and in the following photo two appear.

Muskallonge Lake beach 10b

However, there were very few compared to Agawa Bay. Here is a typical aggregation of Muskallonge stones, representing the Green Bay lobe.

Muskallonge Lake beach 1b

Here is a corresponding photo for Whitefish Point, along the Lake Michigan lobe’s route.

Whitefish Point 9b

While to my eye there did seem to be more reds and a few more greens at Muskallonge, and a few more grays and browns at Whitefish point, I don’t think the differences would hold up in a proper sampling procedure and statistical analysis. Furthermore, when I bring in a photo from Illinois Beach State Park (below), I am hard pressed to say that it is closer to one U.P. site or the other.

Illinois Beach 2b cropped

Nevertheless, the two years’ travel and study were enjoyable, and I learned a lot especially from studying the Canadian bedrock. The glacial drift may not provide additional support for the route map shown above, but the scratches on bedrock indicated by the little arrows in the geologists’ original map certainly are consistent with the turquoise line I added after last year’s trip.

Incidentally, there were places at Muskallonge Lake where there were deposits of black sands, I suspect composed of hematite like I found at Lake Maxinkuckee last winter.

Muskallonge Lake beach 4b

The next installation from this trip will be more biological.

Glacial Drift Comparison

by Carl Strang

This is the third installment describing my 2008 vacation to look at the route followed by the Lake Michigan lobe of the latest (“Wisconsin”) glacier. I followed the highway northeast to Timmins, Ontario, and camped a couple nights at the nearby Kettle Lakes Provincial Park. This is an area where the bedrock is covered by glacial drift and outwash, as is the case in DuPage County. As I explored the park’s trails I was struck by how familiar the outwash looked. The colors and proportions of little stones seemed very similar to ours, except for the absence of the Devonian shale and the Niagara dolomite. Those would not be expected, because they are from the bottom of Lake Michigan and from its rim, well downstream from Ontario on the glacier’s route.

 

Outwash at Kettle Lakes

Outwash at Kettle Lakes

The story was different at Nagagamisis Provincial Park, which I reached after driving far enough northwest that I was northeast of Lake Superior. The drift stones at Nagagamisis had different colors in different proportions and did not look familiar. This is intuitive rather than a quantitative measurement, but I feel pretty confident about it. There were plenty of basalts, but a higher proportion of white granites, and few red granites and gneisses. The surprise was that there was a presence of Paleozoic sedimentary pieces, including fossils. When I examined the maps I found that the glacier indeed had passed over an area of Paleozoic bedrock that lies between Hudson Bay and Nagagamisis.

 

 

Outwash at Nagagamisis

Outwash at Nagagamisis

 

 

 

Closeup of horn coral fossil

Closeup of horn coral fossil

A couple days later I camped on the shore of Lake Superior at the Agawa campground of Superior Provincial Park. The stones on the beach there were dominated by reddish granites and black basalts or diabases. There were pale quartz pieces, but little or no sedimentary rock. The high proportion of red granites, a significant percentage of which were mixed with greenstone minerals, was surprisingly unlike what we see in DuPage County. I would have thought this spot was in the path of the Lake Michigan lobe, but that appears not to be the case.

 

 

Agawa beach stones

Agawa beach stones

 

 

 

Agawa beach closeup

Agawa beach closeup

 

My next examination of drift was at Whitefish Point, near the tip of the Upper Peninsula of Michigan on the Lake Superior side. Here the rock mix was, to the eye, familiar and like that of NE Illinois. This spot seems unavoidably in the path of the Lake Michigan lobe.

 

 

 

Whitefish Point beach stones

Whitefish Point beach stones

A final stop, at Illinois Beach State Park, was similar except that the local Paleozoic stones were back in the mix.

 

 

Illinois Beach State Park stones

Illinois Beach State Park stones

This all was satisfying, though my tentative conclusions don’t withstand close scrutiny. A quantitative and perhaps chemical examination of the rocks would be necessary to nail it down. However, my observations are consistent with mapped glacial scratches on bedrock. It appears to me that the Lake Michigan lobe passed through or near Timmins, on the one (S or SE) side, and Whitefish Point and Door County on the other (N or NW). One test of this idea I intend to make in a future inquiry will be to search for drift on the U.P. west of Whitefish Point. I would expect to find, somewhere, a match to Agawa Bay.

 

 

There will be one final entry in this series, focusing on the biology of the part of Canada I explored on this trip.

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