Museum Visits

by Carl Strang

Planning for the coming singing insects field season has been one of my major occupations this winter. I am looking forward to visiting many new sites, and hope to find some of the species that historically occurred in the Chicago region but which have eluded me so far. Part of that process has been to visit insect collections, gaining information on those species and taking photographs that will help me recognize them.

While at the Purdue University and Illinois Natural History Survey collections, the two museums I have visited so far, I also photographed specimens of species that I have heard but not yet photographed in the field. This will enhance next year’s edition of the guide.

The northern mole cricket is one of those species. This front-end view shows why that cricket is well named.

A note on one specimen said it was collected while flying around in someone’s garage. I had not been aware that northern mole crickets can fly.

Another plan for the upcoming guide is to add pages for the species that have been documented in the Chicago region, but which I have not yet found. Researching those species is getting me better prepared to find them.

There is a Kankakee County record for the common virtuoso katydid, in or near the Illinois Kankakee Sands preserve. That is one species I will be seeking this year.

Walker’s cicada has been collected in a few locations around the region. I need to be alert for its distinctive song in the coming season.

The coral-winged grasshopper will be one of the earliest species for me to seek this spring. They overwinter as nymphs, and have been found mainly in May in past years. I have several locations to check.

The large spots on the sides of the wings, along with the golden wing edges and brightly colored hind wings, are distinguishing features of coral-winged grasshoppers.

Female delicate meadow katydids have unusually long ovipositors. This example will help me distinguish them from green-faced individuals of the dusky-faced meadow katydid. I have not given up hope for the delicate meadow katydid in the region.

Another species I still hope to find is the slender conehead. This one, collected at Illinois Beach State Park in 1906, shows the main distinguishing features of that wetland species: the front of the cone is all black, and there is a right-angle bend in the contour of the pronotum’s posterior edge.

All of this is getting me fired up, but I still have two months to wait. Maybe another museum visit is in order…

 

Singing Insects Guide 2017

by Carl Strang

The main product of my singing insects research is a guide, Singing Insects of the Chicago Region. Each year I update the guide with new information from the field season just past. The Chicago region for this project includes 22 counties from southeastern Wisconsin around to Berrien County, Michigan. Singing insects are defined here as the cicadas, crickets, katydids, and members of three grasshopper subfamilies with sound displays that people can hear (though the songs of some are so high pitched that only young people can hear them unaided). There are around 100 species, though some I haven’t found outside historical records.

title-page-2017

The guide is available for free as a highly compressed PDF document that nevertheless occupies over 5MB, thanks to the many photos. There are maps showing current and historical county records, graphical devices indicating seasonal and time-of-day information, and descriptions of the insects and their songs. Information is presented as well on conservation concerns and ongoing range expansions. To receive the current version of the guide and get on the mailing list for future updates, send your request to me at wildlifer@aol.com.

Singing Insects Wrap-Up

by Carl Strang

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).

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.

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.

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.

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.

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.

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.

Probably my last singing insect photo series for 2016 was of this spotted ground cricket at St. James Farm on October 18.

 

Making a Case 3: Northern Wood Cricket

by Carl Strang

Last year I concluded that I had found northern wood crickets (Gryllus vernalis) in the Winamac State Fish & Wildlife Area in Pulaski County on June 13, based on habitat and sound recordings. In 2016 I returned to that site on May 29, but did not find them singing. On June 3 I heard Gryllus crickets chirping along the Marquette Trail, near the east border of Lake County, Indiana. All were in forest or savanna areas, the singers in deeply layered black oak leaves, usually in shade under black oak trees but some in isolated collections of leaves surrounded by sand.

One of the woodland crickets’ song sites near the Marquette Trail.

One of the woodland crickets’ song sites near the Marquette Trail.

None were in the open grassy areas favored by spring field crickets (G. veletis), even though such habitat was close by. I recorded two of these individuals, and later in the season recorded field crickets in meadow and prairie habitats favored by veletis but where vernalis would not be expected, plus another individual that by habitat should be vernalis, at the Kankakee Sands site in Kankakee County, Illinois.

The results seemed contrary to what would be expected from previous studies.

The likely vernalis (forest) had lower chirp rates than likely veletis (grassland).

The likely vernalis (forest) had lower chirp rates than likely veletis (grassland).

The number of pulses per chirp was unhelpful, with likely veletis ranging 2-4, likely vernalis 3-4. Linear regressions of the two sets of data show, perhaps significantly, the same slopes of chirp rate increase with temperature (physiology of closely related species expected to show a similar response to temperature). The linear regressions indicate that, for a given temperature, forest cricket chirp rates are 1.44/second less than grassland chirp rates. All data I can find in the literature for vernalis were collected from that part of their range where they are sympatric with the southern wood cricket (G. fultoni). Jang and Gerhardt (2005. J. Evol. Biol. 19:459–472) found that fultoni song characteristics differed between populations sympatric with vernalis and those allopatric to that species. They did not study allopatric vernalis. As my recordings may be the only ones that have been made where vernalis is allopatric to fultoni, and given the clear difference between recordings in habitats for likely vernalis and likely veletis described above, so far it appears that habitat, chirp rates and temperatures will be enough to establish the presence of vernalis. The major obstacle to finalizing this conclusion is confirming the identity of the forest crickets. So far I have been unsuccessful in efforts to catch or even see one. Next year I need to continue making recordings and trying to catch and measure suspected northern wood crickets.

Making a Case 2: Prairie Meadow Katydid

by Carl Strang

After more than ten years of study, I still have not found several species of singing insects that historically were known in the Chicago region. One of these was the prairie meadow katydid, one of the smaller members of its group. On August 16, Wendy Partridge and I were checking out the bike trail near the nature center at Illinois Beach State Park. Through the SongFinder, which allows me to hear high pitches, I heard faint rapid ticking sounds which, when heard from a closer position, resolved into brief buzzes. They were mechanical and katydid-like rather than cricket-like in quality, and didn’t match anything I had heard before. Wendy, with her unusually good hearing, barely could pick them up. Later, checking reference recordings, I decided they fit the song of the prairie meadow katydid. They were not in the habitat I would expect, however, being in dense vegetation where grasses were mixed with woody plants and forbs, generally shaded. That katydid species has been known to occur in that park, however.

Then on September 27 I caught and photographed a small female meadow katydid in a relatively dry portion of the Gensburg Prairie in Cook County.

Posterior portion of the Gensburg Prairie female.

Posterior portion of the Gensburg Prairie female.

Her color didn’t seem quite right for a short-winged meadow katydid, which is a common species at that site especially in the wetter portions. Studying the photos, and looking back at references, I have decided that she was a prairie meadow katydid. Along the way I looked back at all my photos of short-winged meadow katydids, and found two other individuals that met at least some of the criteria for prairie meadow katydid, one in 2011 at Mayslake Forest Preserve, and one in 2014 in the savanna woodland at Illinois Beach State Park.

The Mayslake female

The Mayslake female

The Illinois Beach State Park female

The Illinois Beach State Park female

All three have curved ovipositors that are slenderer in proportion than in a typical short-winged meadow katydid.

Typical female short-winged meadow katydid

Typical female short-winged meadow katydid

All three also have femoral patterns in which there is a lengthwise pair of lines, as in the short-winged, but have ladders of narrow crossbars rather than being clear between them as in typical short-winged. There is enough overlap in body length, according to references, that it is not a consideration in comparing those two species. The ovipositors are too short, and the femur patterns wrong, for straight-lanced meadow katydid to be a consideration. The Mayslake female is different from the other two individuals in three possibly significant ways: the femoral ground color is green rather than brown or tan, the wings are much longer, and the front of the head does not appear to rise so much (this last being a difference mentioned by W.S. Blatchley in his classic Orthoptera of Northeastern North America, which gives unusually detailed descriptions of species).

Anterior portion of the Gensburg Prairie female. Note the abrupt rise of the tip of the head when viewed from the side.

Anterior portion of the Gensburg Prairie female. Note the abrupt rise of the tip of the head when viewed from the side.

Dorsal view of the Gensburg Prairie female. Blatchley describes the wings of prairie females as covering only one-fourth of the abdomen, two-thirds in short-winged females. Furthermore, the tip of the head, when viewed from above, is relatively wide after an inward bending of its sides, expected from Blatchley’s description.

Dorsal view of the Gensburg Prairie female. Blatchley describes the wings of prairie females as covering only one-fourth of the abdomen, two-thirds in short-winged females. Furthermore, the tip of the head, when viewed from above, is relatively wide after an inward bending of its sides, expected from Blatchley’s description.

Compare this common meadow katydid, with its relatively narrow and straight-sided tip of the head, to the previous.

Compare this short-winged meadow katydid, with its relatively narrow and straight-sided tip of the head, to the previous.

 

Side view of the same male as in the previous photo. Again, note the lack of a rise in the top of the head profile.

Side view of the same male as in the previous photo. Again, note the lack of a rise in the top of the head profile.

Blatchley also believed that prairie meadow katydids occur only in “raw prairie,” a description which applies to Gensburg and Illinois Beach but not to Mayslake. I am inclined to regard the Mayslake individual as an anomalous short-winged meadow katydid, but pending study of museum specimens, am naming the other two prairie meadow katydids.

Making a Case 1: Cuban Ground Cricket

by Carl Strang

There is a part of me that likes to keep things simple. There is another part that loves diversity and complexity. Today’s story touches on both those aspects, and features two species, the variegated ground cricket and the Cuban ground cricket. Variegated ground crickets are not well represented in the scientific literature, I think because they seldom come out of their refuges in the soil and have unobtrusive songs. Once I gained experience with them at Mayslake Forest Preserve a few years ago in a happy accident, I began to find them elsewhere, ultimately in every one of the 22 counties in my survey area.

The mix of colors and patterns on the head, in particular, give the variegated ground cricket its name.

The mix of colors and patterns on the head, in particular, give the variegated ground cricket its name.

At roughly the same time, Lisa Rainsong found Cuban ground crickets in the Cleveland area, far north of their previously known range. They are better studied in general, because they are inclined to wander on the surface of the ground. Both of these species are in the same genus, and both have similar songs, long trills that emerge from crescendo starts. Lisa came out to my area in 2014 and made recordings that seemed to establish that variegated ground crickets but not Cuban ground crickets indeed were what I had been finding. That satisfied my simplicity loving side.

Then came September 15 of this year. I was walking the upper trail at Gar Creek Forest Preserve, just south of Kankakee and near the southern edge of my survey region, in a shaded wooded spot adjacent to a ditch in which water was flowing. I noticed a tiny cricket crawling across the trail. Thinking this might be a rare opportunity to photograph a variegated ground cricket out in the open, I got down low and took a series of photos. This was not a variegated ground cricket.

The male was largely black.

The male was largely black.

His head was black, the palps white with black end segments.

His head was black, the palps white with black end segments.

The only songs I was hearing nearby belonged to tinkling ground crickets and what I would have called variegated ground crickets. I made a recording of one of the latter, and farther down the trail toward the Kankakee River recorded another. The two recordings contrasted, the first with a dominant frequency of 8.06 kHz and 53 pulses per second, the second with a higher pitch and lower pulse rate, 8.6 kHz and 38 p/s respectively. The latter fits variegated ground cricket well. The former has the pulse rate of a Cuban ground cricket but the frequency is higher than the 7.0-7.5 range that is typical for that species.

I returned on September 26. It was a very windy afternoon, so singers were difficult to locate and isolate, but I was able to made recordings in the area where I found the suspect cricket. Again there seemed to be two categories of songs, lower pitch with higher pulse rate on the one hand (7.9/52, 7.5/signal not strong enough to read pulse rate), higher pitch plus lower pulse rate on the other (8.2/35, 8.2/34, 8.4/signal not strong enough to read pulse rate).

I found another male wandering on the trail, caught him, chilled him, and took photos against a backdrop for measurement, and upside down to check tibal spurs. The body length of 8mm and what appeared to be uneven tibial spurs seem to confirm that this ground cricket is in genus Neonemobius.

The tibial spurs are the short ones in the center of the photo; the lower one looks longer than the upper one.

The tibial spurs are the short ones in the center of the photo; the lower one looks longer than the upper one.

The only black members of the genus in the eastern U.S. are the sphagnum ground cricket and Cuban ground cricket. Only the Cuban fits this habitat.

I did not have a collecting permit for that site, so I had to release the cricket. Next year I hope to have a permit which will allow me to take one of these crickets home for sound recordings and, ultimately, to provide a voucher specimen which may be a first record of Cuban ground cricket for the state of Illinois if I am right in my identification.

So the story has become more complicated, which satisfies my diversity loving side.

Down the Rabbit Hole in Indy

by Carl Strang

Most bioblitzes occur in the spring, ahead of the main singing insects season. When one was announced for mid-September in Indianapolis, I was quick to sign on. Bioblitzes are good opportunities to go beyond one’s familiar region and gain wider experience, but this one brought enough strange observations that it was somewhat disorienting. The dominant singers everywhere were Japanese burrowing crickets.

Japanese burrowing cricket

Japanese burrowing cricket

That Asian species has been spreading from Mobile, Alabama, where it was introduced to North America in the 1950’s. I expect it eventually to become common in the Chicago region.

Walking a streamside trail at dusk on the first evening, I heard a meadow katydid that did not quite match other species of my acquaintance.

The pale face and eyes reminded me of a recent find by Lisa Rainsong in Ohio.

The pale face and eyes reminded me of a recent find by Lisa Rainsong in Ohio.

Oblique ventral view of the male’s cerci.

Oblique ventral view of the male’s cerci.

Another angle on the cerci. The tips are round rather than blade-like, and the teeth are not unusually long.

Another angle on the cerci. The tips are round rather than blade-like, and the teeth are not unusually long.

The song also was distinct, with very brief buzzes rather than ticks between the major buzzes, and significant pauses between. All of this points to the agile meadow katydid (suggested as a possibility by Wil Hershberger), a southern species not previously documented any closer than Tennessee or Virginia, according to the map in the Singing Insects of North America website.

If that weren’t enough, there were the strange finds in a little wetland area surrounded by a mowed Frisbee golf course at one of the parks.

Two little patches of cattails, grasses and sedges, with wet soil between.

Two little patches of cattails, grasses and sedges, with wet soil between.

There I found a female green-striped grasshopper.

This is a spring species in the Chicago area, totally unexpected in mid-September.

This is a spring species in the Chicago area, totally unexpected in mid-September.

They are known to have two annual generations in the South, and apparently such is the case as far north as Indy.

The bigger surprise was that these little habitat islands held a dense population of dusky-faced meadow katydids.

I caught and photographed males and females to be sure. There was only a little of the red facial spotting and network, but the cerci and ovipositors were definitive.

I caught and photographed males and females to be sure. There was only a little of the red facial spotting and network, but the cerci and ovipositors were definitive.

Also, the song was exactly the same as in the Chicago region. Perhaps this species is more abundant downstate, where invasive wetland plants reportedly are not as thoroughly established as they are farther north.

All in all, it was a horizon-expanding weekend.

 

Beyond the Dead River

by Carl Strang

The Dead River, in Illinois Beach State Park, is so named because most of the time it appears not to be flowing. It ends just shy of the edge of Lake Michigan, a sand bar between the two. Reportedly there are times when enough water comes into it that it breaks through this narrow barrier. The area south of that river is highly protected, and to enter it I needed a permit from the Illinois Nature Preserves Commission.

The Dead River and its extensions are free of invasive wetlands plants, though there are some unconnected wetlands in the area for which that is not the case.

The Dead River and its extensions are free of invasive wetlands plants, though there are some unconnected wetlands in the area for which that is not the case.

Sand savanna and prairie occupy the areas between the wetlands.

Sand savanna and prairie occupy the spaces between the wetlands.

My main goal was to survey the area for wetland singing insects. This was one of my last hopes for finding slender coneheads, but sadly there were none. I am beginning to think they have gone extinct in Illinois. On a much brighter note, I found that the area harbors a huge population of stripe-faced meadow katydids.

This male had developed his full facial color, but an intervening grass blade marred the portrait.

This male had developed his full facial color, but an intervening grass blade marred the portrait.

Profile view of a female.

Profile view of a female.

Illinois Beach remains the only place where I have found this wetland katydid, which even historically was never widely distributed.

I also heard a little chorus of nimble meadow katydids, out in the middle of a river offshoot in a patch of deeper-water arrowheads. There probably are other such groups elsewhere in the area. I plan to get a better idea of their numbers next year. This is the second place I have found them in the region, and the first for Illinois. I spent several days in my kayak this season searching for nimble meadow katydids in places in Illinois and Indiana where they were known in earlier decades.

Apparently the American lotus, shown here, and the yellow pond lily, which filled most of those sites, are too coarse for nimble meadow katydids.

Apparently the American lotus, shown here, and the yellow pond lily, which filled most of those sites, are too coarse for nimble meadow katydids.

I have found them among pickerel weeds and arrowheads, and historically they were known in patches of water knotweeds.

Water knotweed, like those others, is of intermediate coarseness.

Water knotweed, like those others, is of intermediate coarseness.

I suspect that the turbulence created by power boats favors the heavier plants that the insect apparently abhors. I wonder if Illinois Beach State Park also may harbor the last Illinois population of nimble meadow katydids. I have a few more places to check next year.

 

Why the Green Face?

by Carl Strang

This has been a good year for finding additional populations of dusky-faced meadow katydids, a wetland species that has caused me some concern. Once regarded as a ubiquitous marsh insect, they have proven hard to find. In the Chicago region they occur only in remnant marshes and wet prairies with significant amounts of native grasses (though Lisa Rainsong recently reported an Ohio population living in arrowheads), and little or no invasive wetland vegetation. They apparently don’t care for sedges. Such places have become few and far between. So far I have found no evidence of dispersal into restored wetlands.

Dusky-faced meadow katydid, from a newly discovered population at Houghton Lake, a Nature Conservancy site in Marshall County, Indiana.

Dusky-faced meadow katydid, from a newly discovered population at Houghton Lake, a Nature Conservancy site in Marshall County, Indiana.

That said, I have been pleased to find several more populations hanging on in the region. In addition to Houghton Lake, I have found them in two locations in Lake County, Indiana, and have found that they occupy a much larger area at Midewin National Tallgrass Prairie than I realized.

For a time I thought I also had re-found delicate meadow katydids at the Indiana Dunes National Lakeshore. Back in 2012 I got a fuzzy photo of what I thought was that species:

She was gone before I could get anything clearer. The grass-green face seemed to point to delicate meadow katydid.

She was gone before I could get anything clearer. The grass-green face seemed to point to delicate meadow katydid.

When Lisa, Wendy, Wil and I returned to that site in August, we found more green-faced individuals. I also started seeing them elsewhere.

I labeled this photo as a delicate meadow katydid; the green face seemed unambiguous.

I labeled this photo as a delicate meadow katydid; the green face seemed unambiguous.

There were problems, however.

Though some tiny speckles reportedly can occur on the faces of delicate meadow katydids, the green-faced ones often showed the reddish networks typical of dusky-faced.

Though some tiny speckles reportedly can occur on the faces of delicate meadow katydids, the green-faced ones often showed the reddish networks typical of dusky-faced.

This green-faced male has especially heavy reddish markings.

This green-faced male has especially heavy reddish markings.

Also, the ovipositors were too short. They seemed relatively straight, but clearly were less than half the length of the femur.

Also, the ovipositors were too short. They seemed relatively straight, but clearly were less than half the length of the femur.

The songs of some of the males had relatively short intervals of ticks between relatively short buzzes. The ticks all were single, however.

The principal paper published on this species group is by Edward S. Thomas and Richard Alexander (1962. Systematic and behavioral studies on the meadow grasshoppers of the Orchelimum concinnum group (Orthoptera: Tettigoniidae). Occasional Papers of the Museum of Zoology, University of Michigan No. 626:1-31). After studying it closely I have to conclude that all these green-faced individuals are dusky-faced meadow katydids. Thomas and Alexander mention that dusky-faceds can have green faces occasionally (apparently more often around the southern end of Lake Michigan than in the species as a whole). The ovipositor length in females, and the lack of doubled ticks in the males’ songs, seem conclusively to rule out delicate meadow katydids in the individuals I have found. That’s a shame, because it may mean that the species has gone extinct in the region. But I’ll keep looking…

A Not-So-Silent Grasshopper

by Carl Strang

Until a couple weeks ago, the grasshoppers that drew my interest belonged to two subfamilies, the band-winged grasshoppers and the stridulating slant-faced grasshoppers. The former have displays in which they rattle their wings in flight (crepitation), and the latter produce sounds by scraping their folded wings with their hind legs (stridulation). There is an additional small subfamily known as the silent slant-faced grasshoppers. Structurally they resemble the stridulating ones in having faces that slant back distinctly from the tips of their heads, but they lack the minute pegs needed to produce the stridulating sounds.

I had encountered one of the members of this non-stridulating subfamily, the clipped-wing grasshopper, a few times in Indiana marshes.

Here is a female I photographed a couple years ago in Fulton County, Indiana. The slanting face is clear, as is the distinctive wing-end profile which gives the species its common name.

Here is a female I photographed a couple years ago in Fulton County, Indiana. The slanting face is clear, as is the distinctive wing-end profile which gives the species its common name.

On a recent visit to the Houghton Lake Nature Conservancy site in Marshall County, Indiana, I encountered a cluster of these insects in a little marsh meadow. I started hearing buzzing sounds, and was surprised to find that these were being produced by male clipped-wing grasshoppers.

One of the Houghton Lake males.

One of the Houghton Lake males.

They were behaving just like band-winged grasshoppers. Sometimes they crepitated when flushed, but they also were producing the rattling sounds in undisturbed display flights. They also can fly without crepitating. Their buzzes had the same loud, crackling quality as, say, a seaside grasshopper from the band-winged subfamily.

Looking back at the literature, I see that Richard Alexander included this subfamily in his list of Michigan singing insects, and so this is no new discovery. I wonder if the few species in this subfamily started out as stridulators that also could crepitate, and over time were selected to emphasize the latter display, then having ruled out stridulation lost the ability to perform it.

 

« Older entries

%d bloggers like this: