In late November I traveled to eastern North Carolina to visit my brother and his wife for Thanksgiving. They live in a community that surrounds a golf course, and the course abuts their back yard. Rain fell for a day after I arrived, and after it stopped, I could hear crickets chirping out on the golf course.
I made a recording:
These crickets were living beneath the close-mowed turf.
The songs resembled those of northern mole crickets (Neocurtilla hexadacyla), a familiar species in the Chicago region, but were noticeably higher pitched, 1.9 kHz compared to the northern mole cricket’s 1.7. Temperature plays a role here, though, as the recording was made at 17.5 degrees Celsius rather than the standard of 25C for the northern species’ measurement. At 25C the golf course crickets’ songs would be higher still. A review of possibilities in the Singing Insects of North America website pointed to the northern mole cricket and the southern mole cricket (Neoscapteriscus borellii). The latter’s calling song typically is described as a continuous trill at 2.7 kHz, but it also can produce a series of chirps, like those of the northern species but higher pitched.
Here is a recording of a northern mole cricket for comparison, clearly lower pitched despite a warmer 21C temperature:
These North Carolina crickets were singing in a lawn on a hill. Northern mole crickets live in marshes. Southern mole crickets also occur in wetlands, but their habitat range extends to moist lawns. Between the habitat and the higher-pitched songs, I concluded that the golf course dwellers are southern mole crickets.
Last year, while driving a rural road at dusk in Newton County, Indiana, I stopped beside a drainage ditch to listen for slightly musical coneheads. Instead I heard a northern mole cricket, and I realized that I needed to turn off the car engine to hear the low-pitched song.
Northern mole cricket specimen (Neocurtilla hexadactyla). This face-on view shows the modified front legs that make this cricket such a good digger.Recording of northern mole cricket calling song
This turned out to be a lucky observation, as it opened a way for me to conduct my research profitably in this covid19 year. I spent most of the peak singing insect season ditch hopping. I used GoogleEarth and DeLorme map books to identify likely spots where rural roads intersect drainage ditches and streams. Such stops kept me away from concentrations of people.
Typical drainage ditch, Kankakee County
This method gave me a cluster of mole cricket locations on ditches and streams in northeastern Kankakee County, Illinois, all tributaries of the Kankakee River. I also added county records in Pulaski and Fulton Counties, Indiana. Otherwise, the many evenings of searching mainly told me where mole crickets are not, and I have concluded that I will add no more counties in Illinois or Wisconsin.
Map of the Chicago region showing where I have found northern mole crickets (black dots) and identifying counties where there are old records for the species (white dots).
I have satisfied myself that I am not going to find them in Cook County, Illinois, but there still are a few places to check next year in St. Joseph County, Indiana, and Berrien County, Michigan.
The previous post illustrated that the Chicago region has been a dynamically changing landscape through the recent millennia, but that now is overshadowed by the alterations our own species has made. Burgeoning human numbers have overwhelmed the planet’s ecosystems, and the native habitats described earlier mostly have been replaced by agriculture and urban growth in the Chicago region. One of the more dramatic changes is the loss of the Kankakee wetland, once described as the Everglades of the North. That vast wetland was drained for agriculture, and only a few pockets of it survive in preserves. Much of the Kankakee River in Indiana is now a straight channel with constructed high levee banks. Other smaller wetlands received similar treatment, with drainage ditches spreading across the agricultural portion of the region. This is not universally devastating to wetland species. Northern mole crickets, for instance, occasionally can be found along drainage ditches.
Drainage ditch, upper reaches of the Kankakee River, St. Joseph County, Indiana. Note farm fields on both sides.
Prairie mostly has been replaced by agricultural fields, and fire suppression has led to its invasion by woody plants. Specialists such as the prairie meadow katydid, prairie cicada and short-winged toothpick grasshopper are hard to find.
Prairie meadow katydid
My singing insects research has required a lot of driving to reach the relatively tiny surviving preserves and parks to which many of the species are now restricted. Much management effort is required in these little islands to maintain their habitats. There are exceptions, of course. Many other species have thrived under our influence. These are mainly weedy ones such as the striped ground cricket, short-winged meadow katydid and Carolina grasshopper, which do well in disturbed habitats, along with woodland edge species such as the greater angle-wing, snowy tree cricket, and jumping bush cricket, which can meet their needs in residential neighborhoods dominated by lawns and scattered trees and shrubs.
Jumping bush cricket
Habitat destruction is not the only human influence. Climate change is the probable cause of northward range expansions by several singing insect species, and it likely will lead to the extinction of the sphagnum ground cricket from the region as the sphagnum bogs dry up. Say’s cicada and some northern grasshoppers already appear to be pushed out.
Sphagnum ground cricket
Climate change isn’t simply a matter of rising temperatures, as the term “global warming” may seem to imply. Global warming is an accurate enough term, as the simplest way to measure climate change is to track the global average temperature. But the point is that our changes to the Earth’s thin skin of atmosphere are increasing its held solar energy. That energy alters patterns of atmospheric flow and the behavior of storms. Droughts, more frequent flood-causing rains, and seasonal increases or decreases in temperature that seem abnormal are examples of results we observe locally. The singing insects are forced to adjust as best they can. Droughts force sphagnum ground crickets into the wettest parts of their bogs. The severe drought of 2012 concentrated wetland meadow katydids and marsh coneheads into the small portions of the Great Marsh in the Indiana Dunes National Park that remained wet. Oblong-winged meadow katydids may be pre-adapted to such year-to-year variability. Blatchley (1920) observed that their eggs, laid in moist soil, can take 2-3 years to hatch. In my travels through the region I failed to hear a single individual in the years 2010 and 2019, but in other years they have been abundant and widespread. Some of the cicadas and other species may have similar flexibilities.
Oblong-winged katydid
People also have introduced plant species from other parts of the world which, released from the consumers and competitors which hold them in check in their native lands, have become invasive plants here. Their unfair competitive advantage has led to their displacing the region’s native vegetation in an increasing number of places. This is most evident in our wetlands. Wetland meadow katydids and other singing insects are limited to places where native wetland grasses have not been supplanted by reed canary grass, common reed, purple loosestrife, and hybrid cattails. These invasive plants are proving difficult to control, and the outlook is not good for species such as the dusky-faced meadow katydid and marsh conehead. To my knowledge the once relatively widespread stripe-faced meadow katydid now is confined to a single site, and the slender conehead, never known from many locations, apparently is gone from the region.
Stripe-faced meadow katydid
Introductions have not been limited to plants. Several species of singing insects also have been imported. Roesel’s katydid is the most common of these in our region. A European predaceous katydid, Roesel’s was introduced to the Montreal, Quebec, area several decades ago and expanded from there. They occur in open habitats with tall herbaceous vegetation throughout the Chicago region. Japanese burrowing crickets are thought to have arrived at the port of Mobile and spread out from there. They are abundant as far north as Indianapolis, and common in Rensselaer in the southern part of our region. With scattered new appearances each year occurring as far north as DuPage County in Illinois, so far, I expect them to become widespread and abundant here. The tropical house cricket represents the possibility of other, short-term introductions that are unlikely to persist in our climate.
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.
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…
Today’s chapter in the Sound Ideas winter series is a recording from the evening of September 4 last year. I made it in the Miller Woods portion of the Indiana Dunes National Lakeshore. Three very different singing insects can be heard distinctly throughout:
The principal target of this recording produced the annoying, continuous buzzing sound. If you had been there, you would have remarked at how loud this insect was. It was a robust conehead.
Male robust conehead, singing posture
This katydid has a sibling species, creatively named the false robust conehead (Neoconocephalus bivocatus). I haven’t documented bivocatus in the Chicago region, but there are a couple old possible records, so occasionally I record an individual and check the pulse rate and pattern. So far, all have been good old Neoconocephalus robustus.
The other two members of that night’s trio both produced regular, brief chirps: one higher pitched and very regular in its rhythm, the other much lower and a little less regular. The higher pitched singer is famous for the way its chirping rate varies with temperature: count the chirps in 13 seconds, and add 40 to get the degrees Fahrenheit. We know this singer as the snowy tree cricket.
Snowy tree cricket male, taking a break from singing to snack on skin.
That leaves the bass section. The lower pitched continuo is the product of a northern mole cricket. This swale area of Miller Woods is one of only 3 locations where I have found this species to date. I don’t have a photo to show you. True to his name, the mole cricket sings from within his tunnel, and I haven’t yet had a photo op with the critter.
Ah, yes. I see an insistent hand upraised in the back of the class. Yes? Ah, very good. Yes, there is a fourth, more intermittent performer here. Those few added chirps are a fall field cricket’s, practically ubiquitous at this point in the season, and determined to insert himself into any ensemble.
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.
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.
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.
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.
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.
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.
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.
It should be obvious that this title is not a political reference. In this election year both political conservatives and liberals are easy to find as they loudly and shrilly make their cases against each other, trying to attract voters (hm, reminds me of singing insects for some reason). The conservatives I am concerned about here are some of the wetland species of singing insects, habitat specialists that are found only within narrow ranges of ecological parameters and are sensitive to invasive species and other disruptions. Much of my research this year is focused on finding conservative species from my hypothetical list for the region.
I haven’t had a lot of luck with wetland conservatives. The northern mole cricket was one, but I still have not found them anywhere but Houghton Lake. The marsh conehead was another. We thought we also found slender coneheads at Indiana Dunes National Lakeshore, but Gideon discovered when he returned to his lab that they all were marsh coneheads as well, misleading because they were outside the size range of that species he was familiar with in Missouri.
Gideon also learned that the underside of the cone should be black, not gray as it was on the marsh coneheads we found.
But what about the several species of wetland meadow katydids in genus Orchelimum? Regionally there should be four species I haven’t yet found: dusky-faced, stripe-faced, delicate and nimble meadow katydids all have been elusive. I should have found dusky-faced meadow katydids, at least, because they are described as being common in a wide range of marshes. Instead I am finding lots of black-legged meadow katydids, a marsh species that spills into drier areas adjacent to wetlands.
Black-legged meadow katydid
Black-legs sing so loudly, day and night, that I wonder how earlier researchers heard the other wetland species. I wonder if black-legs have become more abundant, conceivably pushing the others out. Have I not been looking in the right places or in the right way? Is the lack of success this year a consequence of the drought? Certainly it takes some effort this year to get wet feet in the marshes. I will continue to look. Last week at Chain O’Lakes State Park in Illinois I saw a number of Orchelimum nymphs that were relatively plain and green.
This female meadow katydid nymph is recognized as an Orchelimum by the curved ovipositor.
On the other hand, black-legs don’t get their full colors until after they mature.
This newly molted adult male black-legged meadow katydid still has not developed his full coloration.
I will continue to look this year, and hope for better conditions next year.
Another area near Culver, Indiana that I wanted to check for singing insects was the Maxinkuckee Wetlands, a state conservation area. Much of it I will need to access by kayak on another occasion. My daytime visit did not produce much, but when I returned at night I was pleased to find a population of slightly musical coneheads, which I first had encountered in the previous week at Indiana Dunes National Lakeshore.
Unlike the mole cricket, as mentioned in yesterday’s post, the slightly musical conehead has a buzzing song.
Along the road edge of the property I heard a different conehead, and traced the song to a small oak.
The impressive volume of the song up close was enough to confirm the singer as a robust conehead. The dry habitat and cone free of black markings support the identification.
Maxinkuckee Wetlands is another site calling for continued exploration.
A priority site in this year’s singing insect survey work was Houghton Lake, a Nature Conservancy property near my home town of Culver, Indiana. The muck, marl and sand soils potentially support communities including wetland crickets and katydids that I have not yet found. Last week I spent an afternoon and evening walking through the site.
The property, named for this lake, is of particular interest as it hosts a population of rare massassauga rattlesnakes.
There are many smaller wet areas on the site, which is a flat postglacial lake plain. It has great botanical as well as zoological biodiversity.
For the most part I found a long list of familiar, common species.
Black-legged meadow katydids, like this female, are expected in wet areas.
As I walked the lanes I heard crickets singing in the pattern of Say’s trigs, but with a more mechanical or buzzing sound quality. I spent some time searching, because I thought they would prove to be a species I had not seen before. This effort was rewarded.
The handsome trig is one of the more beautiful singing insects in the region. They are tiny, around a quarter inch long.
Another unfamiliar sound was a rhythmic “warg warg warg” coming from a couple wet prairie areas. The song’s rhythm was like that of slightly musical coneheads, but that katydid produces a call with a distinctly buzzing quality. A comparison of recordings led me to the northern mole cricket. The mole cricket’s song is a chirp, but so deep that it is not readily characterized as such. Like the handsome trig, this was a species new to my experience. For future monitoring purposes I was pleased at how far their songs carry, and that at least sometimes they can be heard singing in the mid-afternoon.
A few conehead nymphs turned up in sweep net samples.
These probably will prove to be round-tipped coneheads, which mature later than most of their relatives.
An additional interesting insect was a great blue skimmer.
This was only the third individual of this species I have encountered.
Most of the conservative species I’d hoped to find at Houghton Lake eluded me, but I was only able to see part of the site, and I intend to return.
Nature Inquiries 