More Prairie Meadow Katydids

 

by Carl Strang

Last year I first encountered what I thought were prairie meadow katydids (Conocephalus saltans), in my survey of the Chicago region’s singing insects. Further study confirmed my identifications, and set the stage for finding the species in a third location in 2017. On September 2, Lisa Rainsong and I ran into a cluster of small meadow katydids at the Pembroke Savanna Nature Preserve, a Nature Conservancy savanna in eastern Kankakee County. These proved to be a mix of two species, straight-lanced meadow katydids (Conocephalus strictus) and prairie meadow katydids.

A scene at Pembroke Savanna, which I regard as the most beautiful site in the 22-county Chicago region.

Finding these two similar species together provided us with a tutorial in distinguishing them. Most of the individuals were females, and the contrast in their ovipositors could not be starker. Those of the prairie meadow katydids had a slight curve, and were much shorter.

Female prairie meadow katydid, Pembroke

Straight-lanced females have straight ovipositors that typically are as long as their bodies, or longer.

Female straight-lanced meadow katydid, Judy Burton Nature Preserve, Indiana. This one is atypical in having long wings. Most have wings about a third the length of the abdomen.

Prairie meadow katydids have wings that usually are only a quarter of the abdomen length. The knob at the tip of the head is more pronounced, though both species have this knob. The sides of the hind femurs also are different. In prairie meadow katydids there is a pattern of thin lines that resemble a ladder, on a brown leg. There usually is a diffuse black line that appears to be within the straight-lanced meadow katydid’s green hind femur. Some variation occurs in many of these features, so I advise caution and the examination of several individuals within a population.

Males have been fewer in both species, in the populations I have examined.

 

Male prairie meadow katydid, Pembroke

Again, the more exaggerated head knob, shorter wings, and different femur pattern are helpful. Cerci are very different in the two species, also.

Male straight-lanced meadow katydid, from another eastern Kankakee County savanna site.

I did not get a photo showing the prairie meadow katydid’s cerci, but their ends are much shorter, proportionately, than those of the straight-lanced in the photo, comparable in length to the teeth, and bend outward somewhat rather than being straight.

A final curious note from Pembroke was that the prairie meadow katydids were all brown, as the photos show. The straight-lanced meadow katydids had considerable amounts of green color. This may have been the result of local selective pressures, as this is not a consistent difference across the species’ ranges.

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Rounding Out Conehead Maps

by Carl Strang

This has been a good year in my quest for coneheads. The coneheaded katydids of genus Neoconocephalus are represented by six species (historically, seven) in the 22 counties I define as the Chicago region.

 

Sword-bearing conehead. This katydid is named for the female’s long ovipositor.

Prior to 2017, I had found sword-bearing coneheads (N. ensiger) in every county. In a recent post, I detailed the completion of the search for Nebraska coneheads (N. nebrascensis), which can be found in all but the three Wisconsin counties of the region. In another post I described progress in finding slightly musical coneheads (N. exiliscanorus).

 

Robust conehead in singing posture

 

Today I can report that I now have found two more species in all 22 counties: the robust conehead (N. robustus), and the round-tipped conehead (N. retusus). Though it extends into Wisconsin, the round-tipped thins out rapidly south to north, and some effort was needed to find a singing round-tipped conehead in the southern portion of Racine County, the region’s northernmost county.

 

Round-tipped conehead. The shape of the cone and the amount of black pigmentation help in species identification. The large jaws help them with their diet of seeds, and teach researchers to use caution in handling them.

The sixth species is the marsh conehead (N. palustris), which so far I have found only in Porter County, Indiana. Though I continue seeking the slender conehead (N. lyristes), I fear that it is extinct in the region.

 

Slender conehead. This museum specimen from the early 20th Century was collected in what is now Illinois Beach State Park. I have failed to find the species in my thorough exploration of its habitats there.

Wetland Singing Insects Update

by Carl Strang

For years, now, my biggest conservation concern among the singing insects has been in the wetlands. Though our historically abundant prairies in the Chicago region were diminished nearly to nothing by 19th– and 20th-century agriculture, preservation and restoration projects across the region have halted and, to a small degree, reversed that trend. The same could be said for savannas, and our forests did not suffer as much.

Wetlands, like prairies, declined thanks to agriculture, but a new challenge continues to threaten their integrity: invasive wetland plants. Four of these are especially problematic: common reed (Phragmites australis), reed canary grass (Phalaris arundinacea), hybrid cattails (Typha x glauca), and purple loosestrife (Lythrum salicaria). These plants, released from consumers and competitors, have displaced the diverse native species in a large and increasing portion of our wetland acreage. The loss of native wetland grasses, especially, appears to account for the difficulty I am experiencing in finding wetland katydids.

Reed canary grass

Two species that were here historically, I have not found at all: the delicate meadow katydid (Orchelimum delicatum), and the slender conehead (Neoconocephalus lyristes). In the past these were known to occur in four and three, respectively, of the Chicago region’s 22 counties, and I am nearly out of places to check where they might still live. The stripe-faced meadow katydid (O. concinnum), once found in 8 of the counties, appears to be down to a single population at Illinois Beach State Park.

Stripe-faced meadow katydid

Two wetland katydids are doing well. Gladiator meadow katydids (O. gladiator) and black-legged meadow katydids (O. nigripes) are tolerant of the invasive plants, and remain common in every county.

That leaves an in-between category of wetland singing insects that apparently are limited to invasives-free wetlands, and are managing to hang on in a few to several sites. Northern mole crickets (Neocurtilla hexadactyla) occur in wet prairies as well as marshes. In 2017 I added records for two more sites, one of which represented an additional county record. To date I have found them in 10 counties, and remain optimistic that I can add more populations to the inventory.

Dusky-faced meadow katydids (O. campestre) historically were ubiquitous in our marshes. To date I have found them only in marshes with minimal impact by the invasive plants. These katydids seem able to persist in relatively small wetland areas, however, and each year I have been able to add new populations to my list. In 2017 I found them in the Indiana Kankakee Sands preserve, adding Newton County to the record, and in the Tefft Savanna preserve in Jasper County, also a county record. That brings to seven the number of counties where I have found the species, but there are seven more where it once lived, but where my search has been unsuccessful. Dusky-faced meadow katydids also proved this year to be abundant in the panne wetlands at West Beach in the Indiana Dunes National Lakeshore. That was a good find, but I had hoped for delicate meadow katydids there.

Female dusky-faced meadow katydid, Tefft Savanna

Finally, this year I added a third population and county for the nimble meadow katydid (O. volantum). They were singing from arrowheads (Sagittaria sp.) mixed with cattails along Grant Creek in the Midewin National Tallgrass Prairie. That find was made from a kayak, and that is the vehicle from which further searching for the species will need to happen, as this species likes plants growing in relatively deep water. Some places which historically held nimble meadow katydids no longer have them, but several other sites remain for me to check in future years.

Jumping North

by Carl Strang

Of the many species of singing insects that have expanded their ranges northward in the past half century, the jumping bush cricket (Orocharis saltator) has been the fastest mover in the Chicago region. I have done my best to keep up with them ever since 2007, when I first heard their bell-like chirps in DuPage County, Illinois. As their density built dramatically in southern DuPage, the front of their advance typically shifted half a mile north each year.

Jumping bush cricket

At the same time, they were on the move to the east in Cook County. I first found them in Kane County, to the west, in 2014. The line of their advancing front has angled southwest to northeast, suggesting an Indiana source of the invasion, though last year I heard them singing just north of Peoria, well southwest of the Chicago region.

Over the past couple of years, what seemed to be a simple spread has become complicated. First, the advance apparently stalled out in the northeast corner of Cook County, just south of the Lake County border. Farther west, however, the crickets’ expansion has, if anything, accelerated. Following the Fox River, they have moved 8 miles up its east bank in 3 years.

But that’s not all. This year I found them even farther north on the west bank. Then, on September 20, I heard jumping bush crickets singing at the edge of Wauconda, in western Lake County. Subsequent checking revealed that this is an isolated small group, probably a human-assisted introduction. I will be interested in seeing if they successfully reproduce there. In any case, there is no end in sight to the dramatic northward movement of this species, and I will continue to invest some time each year in documenting it.

Map of the Chicago region, showing locations for jumping bush crickets. Black dots indicate counties where the species has become established. Stars indicate farthest north locations: red for 2014, yellow for 2015, green for 2016, and the two blue stars indicate new north locations in 2017, along the west bank of the Fox River in Kane County, and at Wauconda in Lake County.

Handsome Trig Hijinks

by Carl Strang

Last year I followed a tip from Joe Balynas and found handsome trigs (Phyllopalpus pulchellus) established along the Cal Sag Channel, an extension of the Calumet River, in southern Cook County. This apparently was the first finding of the species in northern Illinois.

The handsome trig’s scientific name translates to something like “beautiful little leaf-mouth,” a reference to the expanded tips of its palps.

The Cal Sag Channel points toward the southeast corner of my own DuPage County, and I resolved that this year I would follow the trails along that waterway, and discover how far the trigs had come. That plan was blown to pieces on August 18. I was running along a recreational trail in Wheaton, central DuPage, when I heard the ratcheting mechanical trill of a handsome trig. I stopped to search, and was amazed to find four of the little crickets on the underside of a burdock leaf. Over the following weeks, I heard handsome trigs in scattered other locations in the southern half of DuPage County. I went back to southern Cook, and rode my bicycle west along trails that follow the Des Plaines River, past the point where it forms a complex with the Cal Sag Channel and the Chicago Sanitary Canal. Handsome trigs were audible at intervals along the trail, all the way into DuPage County’s Waterfall Glen Forest Preserve. This was one route by which the species may have reached my county.

What the hey? I have been able to recognize the handsome trig’s song for years, now. I had not found them in my own home county until 2017, and now suddenly they are in scattered spots across southern DuPage. Something about this year has favored the species, as they seem to be more numerous across the Chicago region. In 2017 I also added records for Will County, Illinois, Starke County, Indiana, and Berrien County, Michigan. This last is a new find for southwestern Michigan, but not for the state, as a recent paper reported them in southeastern Michigan (O’Brien, Mark F., and Julie A. Craves. 2016. Phyllopalpus pulchellus Uhler, the handsome trig (Orthoptera: Gryllidae), a confirmed Michigan resident. Great Lakes Entomol. 49:202-203).

The handsome trig is another species of singing insect that is expanding its range northward. It seems reasonable to think that they quietly have been spreading in DuPage County for years, but conditions in 2017 elevated their little local populations to the point where they drew my attention. I will be interested in following their numbers and possible ongoing range extension in coming seasons.

Slightly Musical Coneheads Extend West

by Carl Strang

The slightly musical conehead (Neoconocephalus exiliscanorus) bears my favorite common name among all the singing insects of the Chicago region. That name was bestowed because W.T. Davis, who first described the species in 1887, thought its song was faint. He later changed his tune for good reason, as I find I can hear them easily through the open window of a car driven at a moderate speed. This was, in fact, how I came to add the slightly musical conehead to the species list for the Chicago region. Previously it was unknown in the northern third of Indiana, so I hadn’t expected to find it. Then, prowling the roads of the Indiana Dunes National Lakeshore with me in 2012, graduate students Gideon Ney and Nathan Harness, of the University of Missouri, recognized the katydid’s distinctive rapid buzz pulses.

Slightly musical conehead. They can be brown or green, and have longer cones at the tips of their heads than our other species in genus Neoconocephalus.

Subsequently I found slightly musical coneheads in several northern Indiana counties. They have not been a priority in my 22-county survey of the Chicago region’s singing insects, but I may make them one next year. In 2017 I added three counties: LaPorte and Lake in Indiana, and Kankakee in Illinois. Those last two additions extend the range significantly west, and provide the first observation of the species in the northern half of Illinois, according to the database in the Singing Insects of North America website.

Here is the updated map of my observations for this species:

Black dots represent the counties where I have found slightly musical coneheads through 2017.

And here is a recording of the song:

I often hear them singing in rural roadside ditches, and they are increasingly abundant as you go south. They sing only at night, in my experience.

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.

 

A New North for Nebraskas

by Carl Strang

The Nebraska conehead is a katydid whose northern range limit is within the Chicago region.

Nebraska coneheads can be green, like this one, or brown. The entire underside of the cone is black.

This insect of forest edges and open woodlands sings at night, its high-pitched buzzes readily audible through the window of a moving car. It is common and widespread in the southern counties of the Chicago region, but becomes less abundant, and more locally distributed, farther north. Entering this year, I had found it in nearly all the southern counties. There was a record in the literature for McHenry County, Illinois, but I had not found it there or in neighboring Lake County. I made it a focus for this year’s searching, and was able to complete the map. On July 30 I heard them in both the Lake and McHenry County portions of Chain O’Lakes State Park. I tried to find them in northern Lake County, Indiana, on August 2, but was unsuccessful. On August 11 I found a group of them a short distance north of the southern Lake County border.

Here’s another view.

Chain O’Lakes State Park is not far from Wisconsin, so on August 18 I drove the rural roads of southern Kenosha County, just north of the park. Though the habitat looked suitable in places, there were no Nebraska coneheads. They are already vanishingly thin in Lake and McHenry, so this was not surprising.

The Chicago region range map for the Nebraska conehead. Black dots indicate the counties where I have found the species. The red star marks Chain O’Lakes State Park, the northernmost known location in the region.

For my purposes, I am satisfied that I can close the book on Nebraska coneheads and focus on other species.

 

Currency and Milestones

by Carl Strang

Last week, in a location just north of the Indiana border, I heard a single long-spurred meadow katydid singing in Berrien County, Michigan.

Long-spurred meadow katydid

Earlier in the season, I had found that species in two locations in Kane County, Illinois. These results amounted to two county records and a milestone in my 22-county survey of singing insects in the Chicago region. As I outlined in a blog post last year, the currency by which I measure progress is county records. The goal for each species, however, is either to find it in every county or to conclude that I have reached the limit of its range in the region. When I do so, as now is the case for long-spurred meadow katydids, it marks a milestone in the survey. I no longer need to expend time and effort in searching for that species.

The resulting map for the long-spurred meadow katydid. Black dots indicate counties where I have found the species, and red stars indicate the northernmost locations in Kane, DuPage, Cook and Berrien Counties (i.e., the range limit).

With 100 species and 22 counties, there theoretically could be as many as 2200 county records and 100 milestones. Many species are limited, however, with the edge of their range occurring within the region (as in the long-spurred meadow katydid) or else by having ecological needs which cannot be met in every county. As of this writing, I have a cumulative total of 1129 county records and 32 milestones. The year’s count is up to 87 county records. I hope to reach 100, but if I do, this will be the last year in which I can do so, as I estimate that there will be a total of only about 200 more to be found in future years. The wild card here is in the singing grasshoppers. I have not been very successful in finding these, so if I hit upon a method that opens the door to finding them, that could greatly increase the number of potential county records to be added. At this point, however, it seems more likely that most of these are very limited in their distribution.

 

Closing the Book on Prairie Cicadas

by Carl Strang

The prairie cicada is a small (1-inch) insect that occurs in a few remnant prairies in northeast Illinois. Work by Dennis Nyberg and associates at the University of Illinois Chicago has revealed much of what is known about them in the state. I first gained experience with this species a few years ago at the UIC’s Woodworth Prairie in northern Cook County, then quickly discovered them in two DuPage County locations. I expected then that I would find them consistently in prairie remnants, but this has not proven to be the case.

Prairie cicada, June 2017

Recently I finished checking the last of the remnant prairies I know about in the Chicago region, and have not added any more locations to the UIC group’s 8 sites (they also listed 3 sites in downstate counties). I have not found them anywhere in the region’s Indiana or Wisconsin counties.

All the sites are small, so all the populations are small and vulnerable. Mated females do not disperse beyond their little prairie plots, as far as anyone has been able to determine. If the species is to survive in the region, the landholders (mainly forest preserve districts and railroads) will need to continue managing those sites so that the prairies can persist, and prairie cicadas with them.

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