The Cricket Double Wave

by Carl Strang

This is the time of year when the singing insect season is nearly done, with only the last song dates to note for the few rugged species still singing. I have been writing my annual research summary, and one data set recently completed was my Fermilab field cricket count. In the warm months I take bike rides through Fermilab, a U.S. Department of Energy research site, on roughly a weekly basis. I count the number of singing crickets I hear. The resulting graph has a double wave shape.

Counts of singing field crickets heard during bicycle rides following a standard route through Fermilab.

Counts of singing field crickets heard during bicycle rides following a standard route through Fermilab.

Two species are represented here, the spring field cricket and the fall field cricket. Their songs are identical to the ear. The graph shows that spring field cricket counts increased rapidly from the first appearance on May 18 to a peak in mid-June, then rapidly fell. There never was a time when fewer than 50 crickets were counted in July, probably indicating overlap between the two species, with the last spring field crickets continuing into the last half of that month. Fall field cricket numbers built rapidly to a peak in the first half of September, and exceeded the maximum count for spring field crickets in the same area, before dropping rapidly in early October.

 

A Last Hurrah, Maybe

by Carl Strang

A field excursion for singing insects took me back to Indiana on Friday. The sky was clear in the morning, with the temperature in the upper 50’s F, but conditions deteriorated back to October wind and clouds through the afternoon. As I drove back home I had the feeling that, except for noting last song dates for species I encounter while engaged in other activities, the 2014 field season is done. Nevertheless, I had picked up another 6 county records, bringing the year’s total to 101.

This female fork-tailed bush katydid was my first of that species for Pulaski County.

This female fork-tailed bush katydid was my first of that species for Pulaski County.

The kinked shape of the ovipositor’s dorsal edge, along with the insect’s small size, assured the identification. Note the teeth around the tip, used when cutting into plant tissue for egg laying.

The kinked shape of the ovipositor’s dorsal edge, along with the insect’s small size, assured the identification. Note the teeth around the tip, used when cutting into plant tissue for egg laying.

 

Jumping Bush Cricket Advances

by Carl Strang

The jumping bush cricket is the singing insect species that is shifting its range boundary most rapidly to the north in the Chicago region.

Jumping bush cricket

Jumping bush cricket

This one is worth following annually, and a couple weeks ago I made a few evening drives to find how far they have advanced this year.

Here is the resulting map, on the scale of the 22-county area I am surveying for singing insects. Black dots represent counties in which I have found the species as of last year. Red stars mark the northern extent in 2013, yellow ones 2014.

Here is the resulting map, on the scale of the 22-county area I am surveying for singing insects. Black dots represent counties in which I have found the species as of last year. Red stars mark the northern extent in 2013, yellow ones 2014.

The four yellow stars are in four stream corridors that the crickets sometimes follow. I did not do this check along the West Branch of the DuPage River last year. As you can see, there was a measurable hop north. For the first time I found them in Kane County; they were just south of there in Kendall last year. Also, now they have extended into northern Cook County both along Salt Creek and the Des Plaines River. These new locations represent about a half-mile northward shift, and I will be interested in finding whether they maintain that rate next year.

 

False Alarm

by Carl Strang

A recent moment of excitement proved to be unfounded. I was hosing off the driveway, preparatory to sealing it, when the spray flushed out a tree cricket hidden in the siding.

The color spot seemed confined to the head. Could this be a Davis’s tree cricket?

The color spot seemed confined to the head. Could this be a Davis’s tree cricket?

I never had seen a Davis’s, though I have heard them singing several times. They generally stay high up in trees, and their songs are so buried in the nighttime wall of sound produced by other singing insects that I don’t have a good sense of their abundance or distribution. I spent a good half hour photographing this female before it occurred to me to check the basal antenna spots.

The curved, hook-like shape of the spot on the basal segment told me this was not a Davis’s, whose spot simply would be straight, but rather a narrow-winged tree cricket, a very common species.

The curved, hook-like shape of the spot on the basal segment told me this was not a Davis’s, whose spot simply would be straight, but rather a narrow-winged tree cricket, a very common species.

Nevertheless, there are lessons to be learned in every experience, and now I have a usable photo of the narrow-wing’s spots.

 

Mayslake Catch-up

by Carl Strang

Now that we are getting autumnal weather, it’s a good moment to look back at the summer just past, and at the current hints of what is coming. Here are photos from the past month at Mayslake Forest Preserve.

This dorsal view of a black-legged meadow katydid doesn’t show off his colors, but as he pauses between songs we can see the sound-production structures in the bases of his wings.

This dorsal view of a black-legged meadow katydid doesn’t show off his colors, but as he pauses between songs we can see the sound-production structures in the bases of his wings.

Usually I’m good at spotting bee mimics, but this large syrphid fly had me calling it a common eastern bumblebee for several seconds before I realized my error.

Usually I’m good at spotting bee mimics, but this large syrphid fly had me calling it a common eastern bumblebee for several seconds before I realized my error.

According to BugGuide, “larvae are deposit filter-feeders in water-filled tree holes,” which explains why Mallota bautias don’t turn up very often.

When I spotted the scissor-grinder cicada on the horizontal branch I took advantage of the opportunity for an unobstructed telephoto. Only when I was cropping the picture in the computer did I notice the second individual on the vertical branch.

When I spotted the scissor-grinder cicada on the horizontal branch I took advantage of the opportunity for an unobstructed telephoto. Only when I was cropping the picture in the computer did I notice the second individual on the vertical branch.

So much for summer. Now for hints of the season to come.

This brown, probably male, nymph is a greenstriped grasshopper, the species that will kick off the singing insect season next spring. They get started early because they overwinter in this form rather than in eggs as do most of the species singing now.

This brown, probably male, nymph is a greenstriped grasshopper, the species that will kick off the singing insect season next spring. They get started early because they overwinter in this form rather than in eggs as do most of the species singing now.

This Henry’s marsh moth caterpillar was clambering over the tangled stems of a reed canary grass patch, probably seeking a pupation spot for its winter hibernation.

This Henry’s marsh moth caterpillar was clambering over the tangled stems of a reed canary grass patch, probably seeking a pupation spot for its winter hibernation.

These mink scats, freshly deposited on a path near the stream, are the first sign of that species I have seen in a while. Perhaps this mink will center its winter activities around Mayslake’s wetlands.

These mink scats, freshly deposited on a path near the stream, are the first sign of that species I have seen in a while. Perhaps this mink will center its winter activities around Mayslake’s wetlands.

Reptiles and amphibians are moving toward their hibernacula. Recently I spotted a garter snake that looked different from the usual Chicago version of the eastern garter snake.

It was paler around the head and neck.

It was paler around the head and neck.

The side stripe is on scale rows 3 and 4, and other details support the identification of plains garter snake, a new species for the Mayslake list.

The side stripe is on scale rows 3 and 4, and other details support the identification of plains garter snake, a new species for the Mayslake list.

How to Title This?

by Carl Strang

I debated what tack to take with this post. There are plenty of possibilities. I could have titled it “Two Problems Solved at Once.” Another possibility was “Well, THAT’s Embarrassing.” Then there’s the old standby, “Another Lesson Learned.” “One More Gift from This Field Season” would have had a more positive twist. I even considered “Tastes Like Chicken,” but that’s too tangential. Maybe I should just tell the story.

The roots of this tale go back in two directions, previously introduced in this blog. One had the title, ironic now, of “A Small Mystery Solved.” In it I described how I had tracked certain long cricket trills to cracks and earthworm holes in shaded portions of the mansion lawn at Mayslake Forest Preserve. Though I didn’t see the crickets, and the match wasn’t perfect, the songs sounded close enough to those of Say’s trigs for me to conclude that they were the singing species, even though they otherwise, in the literature and in my experience, are known as a species that lives in vegetation up off the ground.

To my credit I held onto some skepticism toward this conclusion, and was planning to set pit traps at some point to try and catch one of these crickets. Then an unexpected opportunity appeared. During my lunchtime walk on Tuesday I noticed that small bunches of dried leaves that had collected along the curb were harboring some of these singers. I began pulling out leaves so as to expose what I expected would prove to be Say’s trigs. The songs certainly sounded like those of that species. Crickets began to jump out, mostly tiny immatures, and then I flushed a larger one. It manically jumped away. It was light brown, like a Say’s trig, but not totally so, and I wasn’t able to get a clear view. I tried again, and ultimately one sat still for a photo.

This was not a trig, but a ground cricket.

This was not a trig, but a ground cricket.

That one escaped, but I finally caught another, unfortunately damaging him. I was going to need to collect one, anyway, as ground crickets are one of the most difficult groups to identify. I went through the keys in the Singing Insects of North America website, and placed this cricket in the genus Neonemobius. I leafed through the species pages, and ultimately found a match, right down to the pale palps and the head that was light brown on top but dark brown or black in front.

Could they be variegated ground crickets?

Could they be variegated ground crickets?

That brings me to the other root of this story. The variegated ground cricket’s mapped range encompasses the Chicago area, but information about the species in the literature is limited and anecdotal. Prior to Tuesday there was only one northern Illinois record. The most common theme is that they occur among the pebbles at the edges of streams. I have made a few trips trying to find them (one chronicled here, plus two journeys to Kankakee River State Park), always without success.

So the joke’s on me. For years I have been working right next to a sizeable population of variegated ground crickets without realizing it. I have searched in several counties for them, only to find them literally in my back yard. But what about that “Tastes Like Chicken” title? This is not the only cricket whose song sounds to my ear like that of Say’s trig. There also is the spring trig, which indeed lives close to the ground. The melodious ground cricket’s song is not too far off, though the two are readily distinguished by an experienced ear. From now on I need to be suspicious whenever I think I am hearing a Say’s trig. A moist lawn is far removed from a pebbly stream bank, so with that kind of ecological range I expect to find variegated ground crickets in many more places. I am making recordings, and sometime in the coming winter I will attempt to find a way to distinguish the variegated ground cricket’s song. I will share the results here.

Return to Illinois Beach

by Carl Strang

Recent success in finding new species of sand-dwelling grasshoppers brought me back to Illinois Beach State Park in hope of continuing the run. On the beach I confirmed the presence of seaside grasshoppers, but was startled at the color contrast between them and the members of their species at Indiana Dunes National Lakeshore

Here is one of the Illinois Beach State Park hoppers.

Here is one of the Illinois Beach State Park hoppers.

And here is one from Indiana Dunes. Same species, different substrate, a nice study in natural selection.

And here is one from Indiana Dunes. Same species, different substrate, a nice study in natural selection.

Behind the foredune is a flat in which I found three species of singing grasshoppers, all in the band-winged grasshopper subfamily. The pattern continued of a larger species, a smaller one, with a couple Carolina grasshoppers thrown in for good measure.

The larger grasshopper was the by now familiar mottled sand grasshopper. These, like the seaside grasshoppers, were browner than their conspecifics in Indiana.

The larger grasshopper was the by now familiar mottled sand grasshopper. These, like the seaside grasshoppers, were browner than their conspecifics in Indiana.

The small band-winged grasshopper at first made me think of the longhorn band-winged grasshopper.

The head protrudes above the pronotum, the size is the same, and the antennae look long.

The head protrudes above the pronotum, the size is the same, and the antennae look long.

However, in place of the bright red patch at the base of the hind wing, here it is transparent. The hind tibia pattern also is different. Both areas are hidden in the resting insect, and so not subject to selection pressure by predators.

This was a new species for me, the Kiowa rangeland grasshopper.

This was a new species for me, the Kiowa rangeland grasshopper.

A little farther back from the shore, where the first trees appear, other insects may be found.

This is Dawson’s grasshopper, not a singing species (as you might guess from the dinky wings).

This is Dawson’s grasshopper, not a singing species (as you might guess from the dinky wings).

So far the meadow tree crickets I have found at Illinois Beach all have been four-spotteds. This one, too, as evidenced by the shapes of spots on the basal antenna segments.

So far the meadow tree crickets I have found at Illinois Beach all have been four-spotteds. This one, too, as evidenced by the shapes of spots on the basal antenna segments.

Finally, in the savanna zone, the dominant singing grasshopper is Boll’s grasshopper.

Boll’s is in the same genus, Spharagemon, as the mottled sand grasshopper.

Boll’s is in the same genus, Spharagemon, as the mottled sand grasshopper.

Like the mottled sand grasshopper, Boll’s grasshopper has bright yellow in the hind wings.

Like the mottled sand grasshopper, Boll’s grasshopper has bright yellow in the hind wings.

 

The easiest way to tell the two apart is to look at the angle of the back top edge of the pronotum (thorax shield). In Boll’s, here, the angle is more than 90 degrees. In the collared sand grasshopper it is acute.

The easiest way to tell the two apart is to look at the angle of the back top edge of the pronotum (thorax shield). In Boll’s, here, the angle is more than 90 degrees. In the mottled sand grasshopper it is acute.

A final treat from that portion of my exploration was a big, beautiful female bird grasshopper laying eggs in the sand of the trail.

The non-singing grasshoppers of genus Schistocerca can be difficult to tell apart. I decided this one was S. alutacea, the leather-colored bird grasshopper.

The non-singing grasshoppers of genus Schistocerca can be difficult to tell apart. I decided this one was S. alutacea, the leather-colored bird grasshopper.

In Search of the Dusky-faced

by Carl Strang

Last year I recorded an insect song that was much like that of the dusky-faced meadow katydid, at the Bob Kern Natural Area in Fulton County, Indiana. My note from August 31: “I made recording 28 of an interesting meadow katydid that was producing long, loud series of ticks that were irregular but sometimes sort of doubled, followed by a buzz longer than that of a nearby black-leg. It best matches reference recordings of dusky-faced.” A channel too deep and wide for me to cross prevented my getting close enough to see the singer, but I secured a permit to go in there this year. Circumstances delayed me until the last Sunday in September. The marsh has that important quality that seems essential for the rarer wetland meadow katydids: a lack of invasive plants.

The near bog-like soft soil called for hip boots, and slow careful stepping among the bunch grasses and showy Bidens.

The near bog-like soft soil called for hip boots, and slow careful stepping among the bunch grasses and showy Bidens.

I found two grasshoppers of interest. One was a singing species.

This marsh meadow grasshopper had shorter wings than the one I photographed at the magic swale.

This marsh meadow grasshopper had shorter wings than the one I photographed at the magic swale.

The other I thought might belong to the same subfamily, as it had a strongly slanting face.

No question about the head shape.

No question about the head shape.

Later I was glad that I had followed my practice of taking photos of many parts of the grasshopper, from many angles.

Note the oval-shaped area on top of the head in front of the eyes, and the sword-shaped antennae, the basal portion broad and somewhat flattened, the tip more rounded. Those proved to be diagnostic features.

Note the oval-shaped area on top of the head in front of the eyes, and the sword-shaped antennae, the basal portion broad and somewhat flattened, the tip more rounded. Those proved to be diagnostic features.

This was the clipped-wing grasshopper, Metaleptea brevicornis. Note the end of the wing, which gives the species its common name.

This was the clipped-wing grasshopper, Metaleptea brevicornis. Note the end of the wing, which gives the species its common name.

It turns out that this species belongs to a small subfamily, the silent slant-faced grasshoppers: a nice wetland insect, but not a singer. I slogged on across the marsh, but the only meadow katydids were numerous black-legs, a common species. I should try again earlier in the season next year, but I have to consider the possibility that the recorded insect was an aberrant black-leg.

Black-legged meadow katydid (St. James Farm, DuPage County)

Black-legged meadow katydid (St. James Farm, DuPage County)

I headed up to LaPorte County, which I had not surveyed as well as most of the others in my 22-county region. I had visited the Kingsbury Fish and Wildlife Area earlier in the season, and hoped to pick up some county records there from this late date. Indeed I was to end up with 7, but one in particular needs to be related here. One marsh that is adjacent to the Kankakee River has a levee easily walked, so I checked it out, listening with the SongFinder.

The marsh had few invasive wetland plants.

The marsh had few invasive wetland plants.

I heard an unusual meadow katydid song at one point. The buzz was very long, 6 seconds or more, often with long spaces between, and 6 or 7 ticks leading into the buzz. I couldn’t hear it unaided at a distance, but through the SongFinder it was distinctly louder than the songs of nearby short-winged meadow katydids. I slowly moved in closer, needing to be patient and sit still when the singer paused for longer periods, possibly because of my approach.

The location was mundane, a mix of grasses and common forbs, with the insect ultimately proving to be perched on a tall nettle.

The location was mundane, a mix of grasses and common forbs, with the insect ultimately proving to be perched on a tall nettle.

Of all things, it was a dusky-faced meadow katydid.

Of all things, it was a dusky-faced meadow katydid.

In other words, the species I had set out to find in Fulton County showed up in LaPorte County.

This is only the second location I have to date for the species.

This is only the second location I have to date for the species.

I could hear it unaided when I was within 3-5 feet, but the lesson yet again was the necessity of using the SongFinder pitch-lowering hearing aid when searching for these rarer wetland katydids.

The Magic Swale

by Carl Strang

After a summer that seemed dominated by rain and cool weather, late September brought a period of sun and warmth, offering hope of salvaging a field season that had been, on the whole, uninspiring. The Bendix Woods bioblitz brought some good results, and I was happy with my experiences at Midewin and Indiana Dunes National Lakeshore, so things were looking up. On my next stop I was passing a swale when I heard some curious songs through the SongFinder pitch-lowering device that led me to pause.

It doesn’t look like much in the photo, but this wet-bottomed depression had one quality increasingly hard to find in a wetland: a lack of invasive marsh plants.

It doesn’t look like much in the photo, but this wet-bottomed depression had one quality increasingly hard to find in a wetland: a lack of invasive marsh plants.

Long-tailed meadow katydids, not an everyday insect, were a good find, but they were not producing the mystery song.

Long-tailed meadow katydids, not an everyday insect, were a good find, but they were not producing the mystery song.

Reportedly a common species, the marsh meadow grasshopper had evaded my wish for a photo op until this day.

Reportedly a common species, the marsh meadow grasshopper had evaded my wish for a photo op until this day.

One of them stridulated before my eyes, rapidly raising and lowering its hind legs to scrape against the folded wings, producing the characteristic zuzz-zuzz-zuzz… of the slant-faced stridulating grasshopper subfamily.

The marsh meadow grasshopper provides yet another variation in the structural beauty of grasshoppers. The little rectangular shape above the antennae is one of the diagnostic features of this species.

The marsh meadow grasshopper provides yet another variation in the structural beauty of grasshoppers. The little rectangular shape above the antennae is one of the diagnostic features of this species.

Eventually the SongFinder led me to the singers in the swale. They will endure as the highlight of this year’s field season.

Stripe-faced meadow katydids!

Stripe-faced meadow katydids!

This is a species I have sought for years. The hints in the literature are vague in some ways, contradictory in others. I have slogged through marshes, bogs and marl in counties throughout the Chicago region, and yet here, where I would not have expected to find it, was a population of Orchelimum concinnum. They were beautiful, like the other wetland members of their genus, and well named with that ornamental stripe down the front of the head.

The stripe is not simple, but multicolored as you can see.

The stripe is not simple, but multicolored as you can see.

The song was faint to my ear. I needed to be within a few feet to hear it unaided. A few irregularly spaced ticks (3 or 4 in some individuals, 6 or 7 in others) led into a buzz a few seconds long. Increasingly I am leaning more and more on the SongFinder, but perhaps with that knowledge I will have more success in finding other populations of stripe-faced meadow katydids.

Return to the National Lakeshore

by Carl Strang

A couple weeks ago I went back to the Indiana Dunes National Lakeshore, as usual seeking to add to the regional inventory of singing insects. I spent most of my time in the West Beach area.

Behind the beach is a beautiful sand prairie with plenty of blazing stars and showy goldenrods.

Behind the beach is a beautiful sand prairie with plenty of blazing stars and showy goldenrods.

The prairie hosted the same three species of band-winged grasshoppers as at the Memorial Forest in Marshall County, but their relative numbers were different. Carolina grasshoppers were present in small numbers, as at the Memorial Forest, but the other two species were reversed. The dominant one was the longhorn band-winged grasshopper.

They were colored a little differently at this site, but had the small size, bright red hind wings, and protruding head characteristic of the species.

They were colored a little differently at this site, but had the small size, bright red hind wings, and protruding head characteristic of the species.

The larger, yellow-winged species, the mottled sand grasshopper, was present in much smaller numbers.

Its colors were perhaps a little more smudged than at the Memorial Forest.

Its colors were perhaps a little more smudged than at the Memorial Forest.

Down on the beach beyond the vegetation, as is typical of the Lake Michigan shore in the Chicago region, the seaside grasshopper was common.

The camouflage of this species is truly impressive.

The camouflage of this species is truly impressive.

A final stop was the marsh where I have found rare meadow katydids in the past. I thought I heard a couple dusky-faced meadow katydids, but was unable to confirm them visually. I did find a grasshopper that, if my identification is correct, is a relatively uncommon one, living in marshes in a limited portion of northern Indiana, southern Michigan and northwestern Ohio.

Paroxya hoosieri, variously known as the Hoosier grasshopper or the Indiana swamp grasshopper, does not belong to either of the singing grasshopper subfamilies.

Paroxya hoosieri, variously known as the Hoosier grasshopper or the Indiana swamp grasshopper, does not belong to either of the singing grasshopper subfamilies.

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