Even More Melodious

by Carl Strang

Relatively little has been published about melodious ground crickets (Eunemobius melodius). These tiny insects with their beautiful trilling songs first revealed themselves to me at Indiana Dunes State Park in 2012.

Melodious ground cricket

They were abundant in an open, low wet forest associated with the shrub swamp that occupies a central position within that park. The ground there has relatively little vegetation beneath the trees, with abundant rotting logs on the ground, mosses, ferns, and some other vascular plants, but much ground with nothing but wet leaf litter. On another day, I heard a few melodious ground crickets in a similar habitat at Warren Woods in Berrien County, Michigan, and in a shrub swamp in Warren Dunes State Park, also in Berrien. There the matter rested until I heard a single individual in a bottomland forest in Tippecanoe River State Park, Pulaski County, Indiana, late last year. That observation planted an idea: perhaps this species is more abundant than I realized. Flood plain forests, resembling that original site at Indiana Dunes State Park, can be found along all the major rivers in the Chicago Region. Could melodious ground crickets be found in all those places? That set the stage for one of this year’s goals.

I first tested the idea on August 11 at the Momence Wetlands, a state-owned property in Kankakee County, Illinois. As I walked into this Kankakee River floodplain forest, I was struck by its similarity to other places where I have found melodious ground crickets, and before long I began to hear them singing. As I have come to expect, they were on the ground, in or close to rotting logs. I made sound recordings to analyze for confirmation, but the contrast between their songs and those of Say’s trigs (Anaxipha exigua), which were singing nearby up in tall herbaceous vegetation, made the identification clear in my mind before the analysis later confirmed it. According to the comprehensive database used to build the species’ maps for the Singing Insects of North America website, this was the first time the melodious ground cricket was documented in Illinois.

That same day I found them on both sides of that same river in Indiana, adding Lake and Newton County records. With that success in hand, I put some time into searching for melodious ground crickets in other counties and river systems. So far, I have found them along the Kankakee River in Starke and LaPorte Counties, and the Tippecanoe River in Fulton and Marshall Counties, all in Indiana. The significance of this is that the Kankakee River flows west to co-form the Illinois River and flow into the Mississippi. The Tippecanoe joins the Wabash River, flowing south to the Ohio River. Though the Yellow River (a tributary of the Kankakee) and Tippecanoe both cross through Marshall County, their watersheds are well separated by miles of dry moraines and sandy areas. The crickets were absent from bottomland areas that recently had flooded, but rotting logs in slightly more elevated portions consistently held singing crickets.

In Illinois, I found melodious ground crickets in Will County around the confluence of the Kankakee and Des Plaines Rivers, and upstream from there along the Des Plaines in my home county of DuPage. That is as far as I will go with this pursuit as the season winds down, but I expect to add more counties to the list next year. I conclude that at least in this limited but widespread habitat type, the melodious ground cricket can be sought throughout the southern portion of the Chicago region. Here is the map to date:

Map showing counties where I have found melodious ground crickets in the Chicago region, updated with 2017 observations.

I close this post with a couple sound recordings, both made at the Des Plaines Riverway Forest Preserve in DuPage County, Illinois, on September 6. The first, of a melodious ground cricket:

The second recording is the song of a Say’s trig:

Ground crickets, as the name suggests, sing from the ground (or, in the melodious ground cricket, sometimes from within a rotting log). Trigs sing from perches up in the vegetation. In this pair of recordings, the statistics quantify the differences you should be able to hear. The melodious ground cricket had a lower-pitched song, at 5.11 kHz, and a slower pulse rate, at 22/second. The Say’s trig’s corresponding numbers are 6.10 kHz and 31/second. The temperatures near the two singers bring out the contrast even more, the elevated trig at 17.7C and the ground cricket at 19C (i.e., if the trig had been singing at the ground cricket’s temperature, one would expect the dominant frequency and the pulse rate both to be even higher). The two species, as I mentioned above, often occur close to one another, making this difference worth noting.

 

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Sound Ideas: 3 Ground Crickets

by Carl Strang

Today I share recordings of 3 ground crickets. The first of these, the melodious ground cricket, is not very well studied, and recordings of its song are not commonly available.

Melodious ground cricket

Melodious ground cricket

The song is a fairly loud, steady trill with a pleasant tone:

That song is most like that of Say’s trig, which can occur in close proximity as both are wetland species. When such is the case, the distinction is clear. Here is a recording of Say’s trig for comparison:

The recordings are a little misleading in that both species can be equally loud. Next up is the sphagnum ground cricket.

Sphagnum ground cricket. This species does not occur away from sphagnum moss.

Sphagnum ground cricket. This species does not occur away from sphagnum moss.

The song is higher pitched and more rapid than that of Say’s trig, which again often co-occurs.

The final species has an interrupted trill, unlike the continuous singing of the previous crickets. The confused ground cricket usually is found in drier portions of woodlands than the more swamp-dwelling melodious ground cricket.

Confused ground cricket

Confused ground cricket

The song is about one second on, one second off. If there are few other sounds, you may hear some stuttering during the “off” intervals:

 

Wetland Concerns

by Carl Strang

A continuing theme in my regional survey of singing insects is the paucity of wetland species. The only one that is present in good numbers in many wetlands is the black-legged meadow katydid. Other species common in wetlands are habitat generalists such as the Carolina ground cricket and short-winged meadow katydid, which don’t truly count as wetland insects. One clear cause of this problem is the loss of high quality habitat to four invasive plant species (purple loosestrife, reed canary grass, common reed, and cattails). All four are capable of completely taking over a wetland, and examples of this can be found for all four. Small numbers of the singing insects mentioned above can be found in such places, but not the other wetland insect species.

This female long-tailed meadow katydid was a rare wetland species holdout in a small pocket of surviving diverse wetland plants surrounded by cattails, reed canary grass and common reed at Waterfall Glen Forest Preserve in DuPage County, Illinois.

This female long-tailed meadow katydid was a rare wetland species holdout in a small pocket of surviving diverse wetland plants surrounded by cattails, reed canary grass and common reed at Waterfall Glen Forest Preserve in DuPage County, Illinois.

On the other hand, there are some good wetlands out there. Many are small, and this along with their isolation may limit them.

This beautiful little fen at Richard Young Forest Preserve in Kendall County is completely surrounded by woodland.

This beautiful little fen at Richard Young Forest Preserve in Kendall County is completely surrounded by woodland.

Many of the interdune swales at Miller Woods in the Indiana Dunes National Lakeshore have been taken over by the common reed. This one was an exception, but I found only black-legs there.

Many of the interdune swales at Miller Woods in the Indiana Dunes National Lakeshore have been taken over by the common reed. This one was an exception, but I found only black-legs there.

This fen-like wetland at Bluff Creek in Wisconsin’s Kettle Moraine State Forest looks very good. I will want to check it earlier in the season next year.

This fen-like wetland at Bluff Creek in Wisconsin’s Kettle Moraine State Forest looks very good. I will want to check it earlier in the season next year.

Still, I have not given up hope. I found a third good population of mole crickets this year, in a swale at Miller Woods.

Mole cricket tunnels look like miniature mole tunnels. They occur around wetland edges, and occasionally have holes to let out the males’ deep chirping calls, and to provide access for attracted females.

Mole cricket tunnels look like miniature mole tunnels. They occur around wetland edges, and occasionally have holes to let out the males’ deep chirping calls, and to provide access for attracted females.

I also found melodious ground crickets at two new sites in Berrien County, Michigan. Though I did not find dusky-faced or delicate meadow katydids at the Indiana Dunes’ Great Marsh this year, I felt curiously encouraged by this.

Both species were there last year, but with the water level higher in 2013, the vegetation was arranged differently and I did not find them in the same place.

Both species were there last year, but with the water level higher in 2013, the vegetation was arranged differently and I did not find them in the same place.

Maybe the populations of many wetland species took a hit in last year’s drought, and were thinly dispersed in the expanded wet areas of 2013. This is, after all, the first year in which I have surveyed many of these sites. If they need a couple years to recover from the drought, maybe I will find the missing species in the future. Still, how to account for the lack of nimble meadow katydids? This species I have yet to find, anywhere. In the heart of the singing insect season I took my sea kayak into an area where they historically were known.

The channels at the south end of Lake Maxinkuckee in Marshall County, Indiana, have become heavily invaded by purple loosestrife.

The channels at the south end of Lake Maxinkuckee in Marshall County, Indiana, have become heavily invaded by purple loosestrife.

Even the patches of emergent water-dwelling knotweeds, a habitat specifically mentioned in some sources as good for nimble meadow katydids, had none as far as I could tell.

Even the patches of emergent water-dwelling knotweeds, a habitat specifically mentioned in some sources as good for nimble meadow katydids, had none as far as I could tell.

So the bottom line is a disappointing season for wetland species, with a few positive points and hope in the possibility that populations are at a low point from which they will recover.

Encounters Along the Way

by Carl Strang

As another season of field research into the region’s singing insects winds down, I am starting to look back at the highlights. Some of these were chance encounters that provided new photo opportunities. For example, there was a weakened common true katydid I found on a trail at Waterfall Glen in broad daylight. I didn’t have a good photo of the species, and posed him after removing him from the hazardous trail.

Unfortunately I neglected to place his hind legs in a natural position.

Unfortunately I neglected to place his hind legs in a natural position.

Another species for which I want a better photo is the handsome trig. Some were singing on a cloudy day down in Fulton County, Indiana, and one came out in the open, but the low light resulted in a less than sharp image.

Tiny but colorful, the handsome trig lives in the southern part of the region I am surveying.

Tiny but colorful, the handsome trig lives in the southern part of the region I am surveying.

The Indiana Dunes area provided several photographs.

This oblong-winged katydid female was emitting single clicks in response to the more complex songs of nearby males.

This oblong-winged katydid female was emitting single clicks in response to the more complex songs of nearby males.

A four-spotted tree cricket had escaped from my grasp before I could photograph it. While looking for it on the ground where it seemed to have gone, my headlamp revealed something better.

A female tinkling ground cricket, only the second member of the species I have seen (despite hearing hundreds).

A female tinkling ground cricket, only the second member of the species I have seen (despite hearing hundreds).

A similar encounter came when I was trying to get a better photo of a melodious ground cricket at Indiana Dunes State Park. Digging through the leaf litter in the area from which a male’s song seemed to be coming, I turned up a female ground cricket.

When I examined the photos, though, I saw that the palps were white. This was a female confused ground cricket, another species that was singing in the area, and the first female confused I have seen.

When I examined the photos, though, I saw that the palps were white. This was a female confused ground cricket, another species that was singing in the area, and the first female confused I have seen.

One of the last places I visited this year was the Bong Recreation Area in Kenosha County, Wisconsin. The prairie area there is extensive, and has a good population of common meadow katydids.

Despite its name, the common meadow katydid is much less frequently encountered than two of its congeners, the gladiator and black-legged meadow katydids.

Despite its name, the common meadow katydid is much less frequently encountered than two of its congeners, the gladiator and black-legged meadow katydids.

There were a few broad-winged bush katydids in the prairie, but I wasn’t successful in stalking one. This Texas bush katydid had to substitute.

There were a few broad-winged bush katydids in the prairie, but I wasn’t successful in stalking one. This Texas bush katydid had to substitute.

Such encounters, sprinkled through the field season, make for good memories.

Melodious Ground Cricket

by Carl Strang

On Saturday I returned to the Indiana Dunes area. My first stop was the State Park, where I hoped to confirm my suspicion that the abundant trilling coming from the leaf litter in the forest south of the shrub swamp would prove to be the songs of melodious ground crickets. It was a cool morning, which didn’t deter the forest’s Carolina ground crickets, but kept the confused ground crickets quiet. As the morning warmed degree by degree, I heard more and more of the mystery songs.

This is a wet woodland, with scattered plants, a lot of rotting logs, and much of the ground covered by varying thicknesses of leaf litter from the shading trees.

Frequent pairs of large yellow slugs, apparently reproducing, indicated how damp the environment was.

My permit allowed me to pursue the singing crickets. I stalked to the spot where a song was being produced, and slowly moved, ultimately on my knees and shifting my head position, until I had a good idea of exactly where the song was coming from. Most of the time this was leaf litter piled against a rotting log. Then I variously lifted leaves one by one, grabbed a big double handful of leaves and tossed it onto a white t-shirt, or otherwise attempted to expose the singer. More than a dozen such efforts produced two sightings of tiny black ground crickets. Both were quick to jump impressive distances. One got away after giving me only a glimpse, but the other had the misfortune to bounce off a log, giving me a chance to catch him in my hands. I put him into a jar, and later transferred him to a cage and took him home. I needed to confirm that this cricket belonged to the mystery species rather than being a Carolina ground cricket (it wasn’t a confused, lacking the snow-white palps of that species).

The cage set up at home. I provided food, and kept the bottom of the cage moist.

The cricket took a while to get settled, but then in the quiet of the evening began to produce the beautiful high-pitched trill I was hoping to hear. Indeed his identity as a melodious ground cricket is all but confirmed.

Here he is, in appearance practically identical to the Carolina ground cricket and a few other common species.

At some point I will need to check a final point under the microscope, but for now I am happy to keep him alive, protect him from parasitoids, and enjoy his nightly concerts.

Indiana Dunes State Park Mystery

by Carl Strang

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.

The Meaning of “Range”

by Carl Strang

This is the third installment of a weekly series on singing insect species that supposedly occur in northeast Illinois or northwest Indiana but which I have yet to find after several years’ field work. Today I will consider two crickets representing different groups. They have in common a certain peculiarity in their range maps. We’ll start with the melodious ground cricket.

As you can see, the shaded area on this map (from the Singing Insects of North America website, or SINA) places nearly all of Illinois within the range of this species. However, that shaded area is computer generated from the only concrete records, which are represented by the black dots. Note that there are no dots anywhere in Illinois. As far as the SINA database goes, the species never has been found in Illinois, and there are only two records from northern Indiana. Illinois is included in the range thanks to a single record from northern Missouri. The species first was described from Ohio in 1957 by Edward S. Thomas and Richard Alexander. It is very similar to the Carolina ground cricket physically, but its song is described as a more melodious trill (lacking the Carolina’s discordant overlay of tones), and its habitat is narrower, limited to bogs and marshes. Even in Ohio there are few locations. The map shows melodius all over Florida, where Thomas Walker (who runs the excellent SINA site) is located.

The next example is the prairie tree cricket.

Northeast Illinois and northwest Indiana are included in the range for this species thanks to two records for Cook County, Illinois, from 1934 and 1935. On the other hand, two records from Iowa probably would have led the computer to shade our region even without those old Cook County records. I mentioned in an earlier post this year that I am looking for prairie tree crickets in sweep samples from meadow and prairie areas, but so far have found only four-spotted, and black-horned/Forbes’s tree crickets in that sampling.

These examples underline the need to be careful in thinking about the geographic range of species. Some singing insects are relatively general in their habitat choice, or tolerant of human alterations in the landscape, or simply have been fortunate to have passed through the sieve of history unscathed. They are the common ones. Shaded areas in range maps like SINA’s represent them best. Other species are much pickier, or their lower densities have made them subject to more frequent local extinctions over time. They are best represented by dots. The best example I have encountered here is the sphagnum ground cricket, which appears indeed to be limited to the narrow confines of sphagnum moss areas. These were more ubiquitous in the broad zone which trailed the last continental glacier north, but then in southern parts became isolated in little bits here and there.

I am not removing melodious ground crickets or prairie tree crickets from my hypothetical list for our region, but until I find them I will not list them as definitely occurring here today.

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