Landscape Ecology of Singing Insects 2: Human Influences

by Carl Strang

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human numbers have overwhelmed the planet’s ecosystems, and the native habitats described earlier mostly have been replaced by agriculture and urban growth in the Chicago region.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Prairie mostly has been replaced by agricultural fields, and fire suppression has led to its invasion by woody plants.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.

Roesel’s katydid

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.

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…


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.


Sound Ideas: Coneheads

by Carl Strang

When I mention the coneheads to people unfamiliar with singing insects, the response almost always is a smile. I have to agree: one reason why the slightly musical conehead is my favorite singing insect (at the moment) is that name. Our coneheads are all katydids in genus Neoconocephalus. I have been fortunate to spend some time in the field with Gideon Ney, a Ph.D. student at the University of Missouri who is working out of a lab led by Johannes Schul that has done a lot of work with the evolution of that group. Thanks to Gideon I am aware of two species of coneheads that are not supposed to occur as far north as the Chicago region, but turn out to be at least locally common. Today I share recordings of the 6 documented species in the region. Warning: these are not delightfully musical or even (despite the name mentioned above) slightly so. We’ll ease into it with one that is somewhat pleasant to hear: the sword-bearing conehead. Its song:

That recording was made in a grassy upland meadow, typical habitat for the species, but close enough to the edge of the woods that a few common true katydids came through loud and clear. The conehead’s song is the continuous string of rasping ticks or brief buzzes. It has been compared to the sound of a sewing machine or a distant steam locomotive.

The sword-bearing conehead is named for the very long, straight ovipositor on the female.

The sword-bearing conehead is named for the very long, straight ovipositor on the female.

The next species also has a discontinuous song. The slightly musical conehead was given that name because W.T. Davis, who described it, thought it was not very loud (though he later changed his mind on that point).

The rasping sounds are easy for me to hear even with my older ears. This is a wetland species, and the males typically sing in unison.

The coneheads are named for the structure on the tip of the head, especially prominent in the slightly musical conehead.

The coneheads are named for the structure on the tip of the head, especially prominent in the slightly musical conehead.

Another species with an interrupted song is the Nebraska conehead.

The buzzes are not as rough as in the previous species, and will be heard in bushy undergrowth of woodlands, or sometimes bushes out in fields. In the southern part of the Chicago region, where the species is more common, the males sometimes sing in unison as well.

Male coneheads often sing head down. It has been speculated that the cone helps them penetrate the vegetation beneath when they are disturbed and drop to hide. Nebraska coneheads have medium sized, all black cone undersides.

Male coneheads often sing head down. It has been speculated that the cone helps them penetrate the vegetation beneath when they are disturbed and drop to hide. Nebraska coneheads have medium sized, all black cone undersides.

The remaining 3 species all have continuous buzzes. Most common region-wide is the round-tipped conehead, a katydid of meadows and roadsides.

Listen for a crackling sound in this continuous buzz.

Here the cone is short, round, and has a small black area near the tip.

Here the cone is short, round, and has a small black area near the tip.

Next is the marsh conehead, which so far has turned up only in the marshes of the Indiana Dunes parks.

The sound resembles that of the round-tipped, but comes from a wetland rather than dry upland habitat.

The cone of the marsh conehead may be all green as in this female, or show variable darkness of color.

The cone of the marsh conehead may be all green as in this female, or show variable darkness of color.

For the grand finale, here is the very loud song of the robust conehead:

This can be so loud as to be painful to the ears. It carries for long distances, as you may imagine, and is easy to hear from a car at any speed.

The robust conehead’s cone is unmarked and proportionately short. Any conehead species can come in green or brown.

The robust conehead’s cone is unmarked and proportionately short. Any conehead species can come in green or brown.

The robust conehead is most abundant in areas with dry sandy soils. Its habitat range is fairly broad, from open woodlands to prairies to corn fields.

There are at least two other species which are supposed to occur in the region, but which I have not found. Perhaps next winter I will have recordings of false robust coneheads and slender coneheads to share.

Where are the Conservatives?

by Carl Strang

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.

Chasing Coneheads 2: Indiana Dunes

by Carl Strang

[Note: Gideon later wrote to share his conclusion that the coneheads we collected were in fact marsh coneheads. The individuals in that population are larger than the ones he was familiar with in Missouri, and the strange gray underside of the cone also was misleading. He later found slender coneheads in another part of their range.] Gideon Ney, Nathan Harness and I reconvened at Indiana Dunes National Lakeshore. We set up camp, but then had to wait out a long afternoon rain wondering if it would stop, if an evening’s search would be any good. The rain stopped an hour before dusk, and we set out prepared to wade through tall wet marsh grasses. We stopped at a corner of the Lakeshore’s Great Marsh, and traded stories as the light faded away. We started hearing the shrill buzzes of coneheads, and began to stalk them. Some of the early ones appeared to be marsh coneheads (Neoconocephalus palustris), which Gideon and Nathan had encountered in Missouri. Then we started catching different ones, and Gideon became increasingly excited as he ticked off characteristics, ultimately concluding that these were the long-sought slender coneheads.

Slender coneheads have medium-sized cones with nearly all the underside darkly pigmented. The Nebraska conehead is similarly marked, but occurs in wooded habitat rather than marsh, and has an interrupted rather than a continuous song.

Most of the ones we found were brown rather than green.

They usually sing head down. This one I disturbed, and he froze after changing position.

Nathan also found plenty of meadow katydids to study back in the lab.

Nathan and Gideon inventory their haul.

They took live katydids back to Missouri, so they can record their songs under controlled conditions in the lab and then get detailed DNA and other biochemical analyses to compare to other conehead species.

Ultimately Gideon hopes to collect slender coneheads from several locations. This species is interesting because it occurs in scattered, separated locations from the Atlantic coast to a site in northwest Illinois. How will its population genetics reflect this indication of a storied evolutionary history?

The night had one concluding chapter, which I’ll share in the next post.

Chasing Coneheads 1: Illinois Beach State Park

by Carl Strang

Last winter I was contacted by Gideon Ney, a graduate student at the University of Missouri in the laboratory led by Johannes Schul. Their focus is the evolutionary relationships among katydids, and members of that research group have published significant analyses of coneheaded katydids, genus Neoconocephalus. One species which they had not yet studied is the slender conehead, Neoconocephalus lyristes, and Gideon found my post in this blog on that species last winter. There I mentioned my interest in finding lyristes, and we corresponded through the succeeding months as we planned our hunt for it. Gideon and another student from that lab, Nathan Harness, who is beginning a study of Orchelimum meadow katydids, came up last week. They started at Chain O’Lakes State Park in Illinois, and I joined them the next day at Illinois Beach State Park. We set up camp, did some scouting, then relaxed in the afternoon.

Gideon and Nathan enjoy the inland sea waters of Lake Michigan.

Coneheads for the most part sing after dark, and we began to drive the roads with windows and ears open as dusk deepened to night. The first conehead we found was the sword-bearing conehead, a common species of dry meadows.

The face of a sword-bearing conehead. The English name for the group refers to the structure protruding from the top of the head between the eyes. In this species the cone has a crescent-shaped black mark near the tip.

The sword-bearing conehead is named for the female’s ovipositor. Gideon caught one and held it for my photo.

Here you can see that the ovipositor extends slightly beyond the wings.

Most of the coneheads we found had unornamented cones like those of the robust conehead, which I found at Kankakee Sands last month. However, the song was not nearly as loud, and the tentative conclusion was that these belonged to a different species, the false robust conehead. We heard a good variety of singing insects, but no slender coneheads, and so made plans to shift to Indiana Dunes National Lakeshore the next day (to be continued).

Slender Conehead

by Carl Strang

The next species in my series on singing insects which may occur in northeast Illinois and northwest Indiana but which I have not found is the slender conehead. Here is the range map from the Singing Insects of North America website (SINA).

This appears to be another example of a species better represented by the dots on the map, which indicate concrete observations, rather than by the shading that connects them. The notes on the SINA page for this species refer to its disjunct populations. It is described as a species of bogs and marshes, and its song apparently is a continuous buzz like that of the round-tipped conehead.

Over the years the slender conehead has been found repeatedly in 3 counties in northern Illinois: Cook, Lake, and Carroll (the last in NW Illinois). It also was found once in Porter County, Indiana, in 1935. Likewise, all Illinois records are 1935 or older except for one undated record for Lake County and one for Carroll.

So far, every conehead population I have encountered has consisted of widely scattered individuals. For a species to persist in a narrowly defined habitat like a bog or a marsh, I therefore would expect the geographic extent of the marsh to be fairly large, to sustain a big enough population of slender coneheads to resist local extinction. Thus at some point I should seek out large marshes in the counties where the slender conehead has been found in the past. Perhaps the best starting point is the Indiana Dunes State Park (in Porter County), which has extensive marsh and bog areas that are relatively high in quality. It goes on my list for next year.

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