October’s cold gradually is silencing another year’s array of singing insects. In recent weeks I have made some final trips to squeeze just a little more data out of the season.
In early September I succeeded in catching an Autumn yellow-winged grasshopper with actual yellow wings (most of them in the region have had red-orange hind wings).
On October 5 I made a final trip up to Illinois Beach State Park, and found some stripe-faced meadow katydids still singing.
By then, of course, they had developed their full color.
I was able to complete a photo series on the species with some cerci shots.
On October 11 I returned to Gar Creek Forest Preserve in Kankakee County and made more recordings. I did not find any more Cuban ground crickets crossing the trail, but was surprised by several variegated ground crickets doing so.
I had never before seen a variegated ground cricket, like this male, wandering in the open.
This female has an interesting pattern of pale dashes on her wings.
It’s reasonable to assume that they walk about at night for most of the season, but like many singing insects extend their usual nighttime activity into the day as temperatures cool. I was glad to get the visual confirmation that this species is at the site along with the (probable) Cubans.
Probably my last singing insect photo series for 2016 was of this spotted ground cricket at St. James Farm on October 18.
Spotted ground crickets have been a challenge for me. There are old records of them in several of the counties I am surveying for singing insects, but I had not found them prior to this year. Prompted by Lisa Rainsong’s results from the Cleveland area, I made a goal of finding them this year. I knew what the problem was: to my ear, recordings of their songs are very similar to those of Carolina ground crickets, which I have found throughout the region. Here is one of my recordings of the latter species, made at 58 degrees Fahrenheit (all recordings in this post have been equalized to remove low-frequency background noise, mainly from traffic):
Here is another, this one at 56 degrees F.
I describe the Carolina ground cricket’s song as a continuous purr or very rapid trill, in which pulsing sections alternate with steadier trills that do not pulse.
Contrast those sounds with the following two recordings of spotted ground crickets. The first was made at around 80 degrees F.
The second was made at 71 degrees F. There is a noticeable drop in both pitch and rapidity of the pulses.
After my experience this year I feel confident that I can distinguish the spotted ground cricket’s song, but I still need to listen carefully. The pulses are regular and continuous, lacking the non-pulsing sections of the Carolina ground cricket’s song. The sound is rougher, grittier, and I would not describe it as a purr. Also, study of sonographs reveals that the spotted ground cricket actually has minute pauses between the pulses, in contrast with the Carolina ground cricket’s more continuous sound production.
Here is a female spotted ground cricket. The mottled, spotted pattern especially of her abdomen is a source of the name.
This male spotted ground cricket is missing a hind leg, possibly the result of a battle with another male. The yellowish rims around the compound eyes are a prominent feature of this generally brown species.
So far it seems to me that spotted ground crickets prefer closed-canopy forest or woodland areas with some accumulations of leaf litter where forest floor vegetation is sparse. The soil needs to be well drained yet moist. Most commonly this seems to mean soils heavy in sand or gravel, but hillsides with denser soils sometimes have spotted ground crickets, too, and I have found them in several of DuPage County’s clay-soil woodlands.
During a 3-day Wisconsin trip last week, I made a lot of stops in Racine, Walworth and Kenosha Counties, the most remarkable of which was a state natural area, Lulu Lake, in Walworth County.
The site includes a large, high quality bog.
For once, the songs of the sphagnum ground crickets were not buried among those of Say’s trigs, as has been true at other bogs I have visited.
The bog is surrounded by hills of glacial outwash gravel.
Those hills held two species I have not observed elsewhere in Walworth County to date: tinkling and spotted ground crickets. The former seem to prefer dry woodland edges on well drained sandy soils. The latter like moist shaded spots in woods on well drained sandy soils.
The bog is reached from the south by a long walk through a meadow with a good percentage of prairie plants. This curve-tailed bush katydid was a resident of that meadow.
One more photo from the Wisconsin trip comes from an Interstate rest stop, also in Walworth, where I found my first straight-lanced meadow katydids for that county.
Nancy Collins had remarked that the straight-lanced males on her site had brown cerci. Going back, I find that this is true of every male I have photographed over the years.
This was a very productive trip, resulting in 22 county records for the three days.
Earlier this season I scouted some new sites in Berrien County, Michigan, and on Sunday I returned to see what singing insects I could find in the early portion of the peak season. A first quick stop at Mud Lake Bog produced a hoped-for population of sphagnum ground crickets, and I was reminded how utterly teeny tiny they are.
Most of the day, and a return trip in the evening, went into a place in the eastern part of the county called Chikaming Township Park. If this were Illinois, I wouldn’t expect much from a park district administered at the township level, but this is a good and well maintained site, and it yielded a pile of county records for my study. One of these was provided by a female curve-tailed bush katydid that flew to a landing right in front of me on one of the trails.
The dark-tipped green ovipositor with this shape and proportions, along with the katydid’s overall size and the habitat, permitted the identification.
After release, she hung around long enough to let me take a single usable, if not absolutely sharp, photo.
Perhaps the most bizarre observation came as a result of the day’s odd weather. I drove through intermittent rain to get to Berrien County, and waited out the last shower before going out onto the Mud Lake Bog boardwalk. Dark clouds remained until mid-afternoon, but they slowly drifted east and the sun was revealed at 4:00 local (eastern) time. Almost immediately, Chikaming’s swamp cicadas began to sing. These generally are limited to mornings, but here they were going in the late afternoon. This site proved to have the largest concentration I have encountered to date. At one point I wandered into a song battle taking place among a trio of males in a meadow with scattered tree saplings. One allowed a close approach.
None of our other cicadas matches the swamp cicada’s heavy black coloration.
Later in the evening I was able to pick up some additional species.
Among them was this Forbes’s tree cricket.
The highlight of the day, though, came at another site, Galien River County Park. I had set a goal for this season of listening for spotted ground crickets, which historically have been documented in several Chicago region counties, but which I had not noted to date. Described as a forest species, the spotted ground cricket’s song to my ear is similar to that of a common and widespread species, the Carolina ground cricket. I realized that while some of the forest crickets at Galien River indeed were Carolina ground crickets, others sounded a little different. I made recordings, and listened carefully, and was pleased to conclude that spotted ground crickets were there as well.
An example of a spotted ground cricket location.
The songs have a similar tonal quality and pitch range to my ear. Where the Carolina ground cricket’s song is a steady purr with intervals of added overtones, the spotted ground cricket’s song is composed of regular pulses (about 4 per second), has no overtones, and lacks the continuous steady sound.
Indiana Dunes State Park is an older preserve than the National Lakeshore that surrounds it. Last week I spent a day there searching for singing insects. As was true at the National Lakeshore earlier in the month, most of the species I found were familiar, but there were a few added ones. For instance, a female rattler round-wing katydid was climbing the outside wall of the park’s nature center.
Later in the evening I heard a couple males singing nearby.
Also that evening I heard a number of jumping bush crickets. The dunes area had, as expected, gray ground crickets.
The day also brought a mystery. As had been the case at the National Lakeshore forest, confused ground crickets were common in the shaded areas, and there were a few tinkling ground crickets around the dry edges. In addition, however, in the wet-mesic forest south of the State Park’s great marsh, and extending well into the wooded margins of the marsh, a common third species was singing a clear and steady trill. It was similar in pattern, but distinctly lower in pitch and with a different tonal quality, than the Say’s trigs that were abundant in more open areas nearby.
Red oaks, ferns and deep leaf litter were characteristic of the mystery cricket’s song sites.
I remembered that the spotted ground cricket is a forest species I had not yet found, and thought that perhaps this would prove to be the solution. Later, however, when I consulted reference recordings, I was reminded that the spotted ground cricket has a pulsing trill unlike the mystery cricket’s steady song. Reviewing other possibilities, I hit upon the melodious ground cricket. The song was very close to what I heard.
The melodious ground cricket is not as well known as many other ground crickets. Edward S. Thomas and Richard Alexander first described it in 1957, and their work provides much of what has been published about it, at least in the North. They characterized it as a marsh species, but their more detailed site descriptions often, if not usually, place it among woody plants. “The majority of our specimens of melodius were secured by tearing apart a soggy, decayed log, honey-combed with insect burrows, about 20 feet from the marsh proper.” While this supports my tentative identification, at some point I will need to get back there and catch some of these crickets to make a positive determination.
Two of the singing insect species that I have not found in northeast Illinois or northwest Indiana, but which have been collected here, are the spotted ground cricket and woodland meadow katydid. Both are described as woodland or woodland edge insects.
Looking back at Hebard’s 1934 monograph, which reviewed the Orthoptera of Illinois, I see that his only spotted ground cricket location in northeast Illinois was Deep Lake, in the northern Lake/McHenry County area. Other Illinois records for this species, all 1935 or older, are in Cook and Will counties. Indiana records include an old one from LaPorte County, as well as one from McCafferty and Stein (1976) for Kosciusko. These records are marked on the map for the spotted ground cricket from the Singing Insects of North America (SINA) website:
Turning to the woodland meadow katydid, Hebard wrote that he found it throughout Illinois in woods undergrowth and openings, and open woodlands, but the only location he gave in northeast Illinois was Willow Springs. Another source in the SINA database had them at Joliet in Will County in 1935. Here is the SINA map.
Indiana records from McCafferty and Stein include Starke County, but otherwise are limited to central and southern counties (they say it “is somewhat uncommon in the northern part. It inhabits roadside vegetation, fence row and marginal wooded areas”).
Both of these species apparently are very locally distributed, at best, in the region. While I will keep them in the back of my mind as I explore our area, and retain them on the hypothetical list as species that may still be present, there seems no justification in actively seeking them.
Waterfall Glen is DuPage County’s most biologically diverse forest preserve. It has the greatest topographic variety, the greatest geological variety, the greatest mix of plant communities, covers hundreds of acres and therefore harbors more species than any other preserve. I had a few specific places I wanted to check for singing insects on my most recent visit there, and will need two posts to describe that afternoon sensibly. My first stop was Sawmill Creek.
In particular I hoped to find variegated ground crickets there. I hadn’t noticed any unusual songs along that stream before, for instance during the Roger Raccoon Club’s creek walks, but I hadn’t known then that the variegated ground cricket is a habitat specialist found on pebbly or sandy stream edges. In DuPage County, covered with tens to hundreds of feet of clay-rich glacial till, the one stream most likely to match this habitat description was Sawmill Creek, which has pebbly banks and in places flows right over the exposed Silurian dolomite bedrock. I struck out, though. I heard no trilling species other than Say’s trigs and Carolina ground crickets, even with the SongFinder, and so my tentative conclusion is that this little-studied ground cricket lives elsewhere than DuPage County.
Next I checked out low wet areas in the western part of Waterfall Glen’s forest, some reduced to muddy patches and others still ponded at this point in the season.
Here I was listening for two other ground cricket species, the spotted and sphagnum ground crickets. The latter was the longest shot, as there was no sphagnum moss, but sometimes species have a broader habitat range than the literature suggests. This time, though, I heard no new species in that part of the forest.
As I followed the trail back to my car I got one very good break, however. I heard a meadow katydid’s buzzing song coming from the edge of the woods about 20 feet away. It wasn’t as loud as a black-legged meadow katydid, and anyway the habitat was high and dry. As I approached the singer I realized I recognized the song. Sure enough, it was a long-spurred meadow katydid.
The long pointy teeth on the cerci confirmed the ID.
This finding was a source of great relief. A few posts ago I mentioned that my failure to hear some of these singing at Blackwell Forest Preserve (except when I wore the SongFinder) had me wondering if my hearing was failing rapidly. Such clearly is not the case. So, what was going on at Blackwell? At some point I’ll have to see if I can find out. Incidentally, at both the Blackwell and the Waterfall Glen locations for long-spurreds there were no coniferous plants present, so here is one of those examples of hints in the literature being misleading.