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.

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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.

Broad-winged Tree Crickets 2015

by Carl Strang

The broad-winged tree cricket was the first singing insect species I found (in 2006, the first year of my study) that had shifted its northern range boundary significantly.

Broad-winged tree cricket

Broad-winged tree cricket

In contrast to the jumping bush cricket, this one seems to be moving slowly, but I have not followed it as closely. This year I put some time into locating northernmost singers, and found two locations.

Chicago region map of broad-winged tree cricket locations. Black dots mark counties where I have found the species to date. Red stars indicate specific locations where I found northernmost crickets singing this year.

Chicago region map of broad-winged tree cricket locations. Black dots mark counties where I have found the species to date. Red stars indicate specific locations where I found northernmost crickets singing this year.

These will be the starting points for next year’s check. The Kane County location is only 1.5 miles south of the southern McHenry-Lake County border line.

Jumping Bush Crickets 2015

by Carl Strang

Of the many species of singing insects that have shifted their range boundaries significantly northward in the last half-century, the one that is continuing to move most rapidly is the jumping bush cricket.

Jumping bush cricket

Jumping bush cricket

In recent years I have been tracing the northernmost locations where I am hearing the distinctive songs of this cricket in northeast Illinois.

Chicago region map of jumping bush cricket locations. Black dots mark counties where I have found the species to date. Red stars indicate specific locations where I found northernmost crickets singing in 2014. Yellow stars mark places farther north where I heard them in 2015.

Chicago region map of jumping bush cricket locations. Black dots mark counties where I have found the species to date. Red stars indicate specific locations where I found northernmost crickets singing in 2014. Yellow stars mark places farther north where I heard them in 2015.

The line marking the front of this expansion is diagonal, southwest to northeast, an orientation that seems to point back toward Indiana as the source of this spread. In the central part of the line I found no indication of an advance from 2014 to 2015, but elsewhere there was a shift of about half a mile. If at some point the movement stalls out, I would expect the west end of the line to catch up with the east end and even up latitudinally, unless there is a Lake Michigan climatic influence.

New North for Lyric Cicadas

by Carl Strang

Last week I took a morning to see if I could extend the northernmost known locations for the lyric cicada. Its song is easy to recognize, but at the north edge of the range they are few, and finding them takes time.

Lyric cicada

Lyric cicada

Last year the northernmost ones in Cook and Kane County were at the Carl R. Hansen Woods and Tekakwitha Woods Forest Preserves, respectively. This year I found them several miles farther north in each county. In Cook County the new north was at the entrance to the Crabtree Nature Center, 6 miles beyond the previous record and now only 5 miles south of the Lake County border.

Chicago region range map for the lyric cicada. Black dots indicate counties where the species occurs. Red stars indicate northernmost locations known through 2014. Yellow stars indicate northernmost locations found in 2015.

Chicago region range map for the lyric cicada. Black dots indicate counties where the species occurs. Red stars indicate northernmost locations known through 2014. Yellow stars indicate northernmost locations found in 2015.

In Kane County, the new location was in Trout Park, at the north edge of Elgin. This represents a northward shift of 11 miles. Did the cicadas jump so far in just one year? That seems unlikely; I simply may not have looked in the right places in the past. I will continue to follow this each year, as I am doing for species such as the jumping bush cricket and broad-winged tree cricket, and in time should be able to get a sense of how rapidly the range expansion is occurring.

Jumping Bush Cricket Advances

by Carl Strang

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

Jumping bush cricket

Jumping bush cricket

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

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

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

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

 

Another River Heard From

by Carl Strang

In a recent post I shared the northward progress of jumping bush crickets in DuPage County. I thought I was done with them for the season, but their numbers seemed to increase over the past couple of weeks, and I was toying with making another check. The opportunity came on Friday. After work I drove up into Lake County to pick up my race packet for a half-marathon I was running on Saturday. On the way back I drove down along the Des Plaines River in Lake and Cook Counties, windows open on a reasonably warm evening. The result was a new north location for the species, just south of the split between Milwaukee Avenue and River Road in Cook County.

Regional species map for the jumping bush cricket. Black dots indicate counties where they have been found to occur so far. The red stars indicate the farthest north locations for Kendall, DuPage and Cook Counties, the last decidedly north of the others.

Regional species map for the jumping bush cricket. Black dots indicate counties where they have been found to occur so far. The red stars indicate the farthest north locations for Kendall, DuPage and Cook Counties, the last decidedly north of the others.

The pattern seems clear. Of the four major north-south rivers that provide the best travel corridors for jumping bush crickets, they have gone farthest north along the Des Plaines River, the easternmost. Next comes Salt Creek, which flows into the Des Plaines at the Brookfield Zoo. Most of DuPage County is drained by the two branches of the DuPage River, whose crickets are yet a little farther south. My earlier check of the Fox River, just west of DuPage, turned up no jumping bush crickets, but I started my search at North Aurora. Might they be a little farther south than that? Last night I checked that possibility, and found them abundant at Kendall County’s Richard Young Forest Preserve. Upstream (north) from there I found a lot of good looking but empty habitat, and then a pocket of the crickets just north of the town of Oswego, still in Kendall County (the lowest star on the map). They are within 2 miles of the Kane County border, but apparently haven’t reached that county yet. So, the northward advance of jumping bush crickets is marked by a line extending southwest from the northernmost red star in the map. It seems likely that they have spread up into northeast Illinois from Indiana, by way of the Kankakee River and perhaps by a broader flow through towns and preserves closer to Lake Michigan.

Jumping Bush Crickets Continue North

by Carl Strang

Of the several species of singing insects that have been expanding their range northward, the jumping bush cricket is the one whose northern boundary has not yet extended beyond DuPage County. Each year I have sought out their north point, and each year it has moved. This year is no exception, and in fact their repetitive burry chirps soon will be heard in north Cook County if the trend continues.

Jumping bush cricket. They are about the same size as a field cricket, but live in trees rather than on the ground.

Jumping bush cricket. They are about the same size as a field cricket, but live in trees rather than on the ground.

Here is the updated map. Green circles indicate known jumping bush cricket locations. This year’s extension is represented by the two northernmost circles in the northeast corner of the county.

Here is the updated map. Green circles indicate known jumping bush cricket locations. This year’s extension is represented by the two northernmost circles in the northeast corner of the county.

The crickets seem to use our north-south streams as travel corridors, and so I took an evening to scout for them along the Fox River, in Kane County just east of DuPage. I heard none on either side of the river from my starting point in North Aurora to the turn in Geneva, though the habitat looks very good. My hypothesis from this is that they spread from Indiana via the Kankakee River to the Des Plaines/Illinois River, and reached DuPage County via Salt Creek and the branches of the DuPage River. The Fox meets the Illinois well to the west, and so additional years will be needed for the crickets to reach central Kane County, either via the Fox or by spreading westward from the West Branch of the DuPage River.

Incidentally, I have tested an idea I had last year, and so far it seems to be working. The jumping bush cricket’s song is loud enough to be heard easily from the car on a driving survey. Seeing one is difficult, however. I have found that they are singing from perches on tree trunks, especially from small shelters in the bark, and the reflecting foliage layers around them confound the source. Looking up the trunk for the lifted, vibrating wings, often leads to success. Another student of singing insects, Lisa Rainsong, has reported in her excellent blog that in her yard in the Cleveland area, they are difficult to find for another reason: they are very active, shifting locations between songs.

The Other Side of Range Extensions

by Carl Strang

The aspect of singing insect studies that has been of greatest general interest, and about which I have presented talks most frequently, is range extensions. Most of the several examples uncovered so far have been northward extensions of species ranges, and it is easy to jump to the conclusion that this is a product of global climate change.

The first species I found well north of where it previously had been known was the broad-winged tree cricket.

The first species I found well north of where it previously had been known was the broad-winged tree cricket.

If climate is the primary influence in these range extensions, we would expect the southern boundary of a species’ range to shift north as well. However, sticking with the example of the broad-winged tree cricket, its range has expanded south as well as north. I know that only because Tom Walker, the authority responsible for the Singing Insects of North America website, informed me that he has found them spreading down into parts of Florida where they had not been before.

Documenting an expansion northward is easier than demonstrating a disappearance in the south portion of a species’ range. It is easier to prove a positive than a negative. Also, when one has limited time and financial resources, it is not possible to travel south and conduct the necessary regional surveys. So, what to do?

The best idea I have had so far is to identify species whose southern range boundaries occur in my region, and make a point of documenting their presence and estimating their abundance from year to year. There are four best candidates.

The dog day cicada Tibicen canicularis has the northernmost southern range boundary. It is mapped down into the very northern edges of Indiana and Illinois, but I have found it a little farther south, at Braidwood Dunes in Will County, Illinois, and in southern Marshall County, Indiana. My notes suggest that its numbers may vary considerably from year to year in the latter location.

Dog day cicada

Dog day cicada

The broad-winged bush katydid Scudderia pistillata is mapped a little farther south, but I have found it infrequent in DuPage County, Illinois, and its season of activity seems to conclude sooner here than it does farther north. So far my surveys have turned it up in Lake County, Illinois, as well, but not farther south.

Broad-winged bush katydid

Broad-winged bush katydid

The striped ground cricket and sword-bearing conehead are abundant in the region. Their southern range boundaries are mapped about half a state south, but that is the same distance as a number of the northern range shifts I have observed. If entire ranges are shifting, one would expect them to be more scarce.

Sword-bearing conehead

Sword-bearing conehead

This is yet another topic of interest I am keeping in mind while surveying the region’s singing insect species.

Singing Insects Range Extensions

by Carl Strang

My other presentation at Saturday’s Wild Things conference reviewed the range extensions by 8 species of singing insects that have turned up in our region in recent years. I ran through them in the chronological order of their discovery, and then offered some general points.

Broad-winged tree cricket (Oecanthus latipennis)

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Map from the Singing Insects of North America website (SINA), 2012. The record in DuPage County resulted from this study, and was added in 2006. Prior to that the species was not supposed to occur in the Chicago region.

Map from the Singing Insects of North America website (SINA), 2012. The record in DuPage County resulted from this study, and was added in 2006. Prior to that the species was not supposed to occur in the Chicago region.

Original range sources: Hebard 1934  (“Northern limits of distribution are Hilliary and Quincy”), McCafferty & Stein 1976 described it as a central and southern species in Indiana, with Tippecanoe County the northern extent. I found them in DuPage County in 2006, and subsequently learned they are abundant throughout the county. They also have reached the junction of the Wisconsin and Mississippi Rivers in Wisconsin.

Jumping bush cricket (Orocharis saltator)

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Jumping bush cricket SINA map, 2012. The added red line indicates the northern range limit as of 1969, when Tom Walker reviewed the genus.

Jumping bush cricket SINA map, 2012. The added red line indicates the northern range limit as of 1969, when Tom Walker reviewed the genus.

Original range sources: Hebard 1934 (Shawneetown northern limit in Illinois; “should however be found throughout southern Illinois as it is known as far north as central Indiana”). McCafferty & Stein 1976 (“known only from the southern two-thirds of the state” with Tippecanoe County given as the northern limit). They are rapidly expanding in DuPage County, abundant in the southern half and spreading into the northern half with new northern limits found annually. I also have heard them at Indiana Dunes State Park.

Roesel’s katydid (Metrioptera roesellii)

Roesel's s-wing female Purdue b

Roesel’s katydid SINA map, 2012. Prior to work by Scott Namestnik and me, the range was thought to end in northeastern Ohio, with a small disjunct area in northeast Illinois. The red dots indicate our added findings in 2012.

Roesel’s katydid SINA map, 2012. Prior to work by Scott Namestnik and me, the range was thought to end in northeastern Ohio, with a small disjunct area in northeast Illinois. The red dots indicate our added findings in 2012.

Original range sources: Roesel’s katydid is a European species that in North America first was found in two suburbs of Montreal, Quebec (Urquhart and Beaudry 1953, Beaudry 1955), and is thought to have been introduced between 1945 and 1951. Vickery (1965), who summarized this history, reported that the species had spread into New York state and Vermont by 1965, and that the long-winged variants that originally had dominated the Montreal population were diminishing in favor of the short-winged forms typical of the European continent. The Montreal population apparently was by then limited by an indigenous parasitic nematode. Roesel’s reached Ithaca, NY, by 1965 (G.K. Morris, as reported by Shapiro 1995), and Long Island by 1990 (Shapiro 1995). Short-winged forms were dominating the St. John, New Brunswick, population by 2008 (McAlpine 2009), and so had arrived some unknown number of years earlier. Nickle (1984) reported finding them in Pennsylvania by the early 1980’s. Roesel’s katydids were collected in two northeastern Illinois counties in the late 1990’s (Eades and Otte, no date). I found them in north central Indiana in 2007, and subsequently Scott Namestnik and I have found them throughout northern Indiana (as far south as Indianapolis) northeast Illinois, and last year the Lower Peninsula of Michigan. Others have added Ohio, Wisconsin and eastern Iowa.

Round-tipped conehead (N. retusus)

Roesel’s katydid SINA map, 2012. Prior to work by Scott Namestnik and me, the range was thought to end in northeastern Ohio, with a small disjunct area in northeast Illinois. The red dots indicate our added findings in 2012.

 

Round-tipped conehead SINA map, 2012. The added red line indicates the northern extent of the range in Illinois in 1934 and in Indiana in 1976.

Round-tipped conehead SINA map, 2012. The added red line indicates the northern extent of the range in Illinois in 1934 and in Indiana in 1976.

Original range sources: Hebard 1934 (“Urbana is a northern limital point”), and McCafferty and Stein (1976) had none north of Indianapolis, but they are so common in northwest Indiana and northeast Illinois now that this is a well advanced range expansion in the intervening decades. I also heard a single singing individual in a meadow at Wyalusing State Park in Wisconsin in 2007.

Handsome trig (Phyllopalpus pulchellus)

Handsome trig 2b

Handsome trig SINA map, 2012. The northern dot at St. Joseph County, Indiana, is the result of Scott Namestnik’s work.

Handsome trig SINA map, 2012. The northern dot at St. Joseph County, Indiana, is the result of Scott Namestnik’s work.

Original range sources: Hebard 1934 (northern limits given as Marion County in Indiana and Monticello in Illinois; “confined to southern and central Illinois”). McCafferty & Stein 1976 indicated a northern extent in Tippecanoe County. In 2009 Scott Namestnik was posting photos of them from St. Joseph County.

Swamp cicada (Tibicen tibicen)

Swamp cicada 4AU 4b

Original range sources: This species was mentioned by Alexander, Pace and Otte in their (1972) Michigan singing insects paper, but they expressed doubt that it was a breeding species in the state. However, a later paper (Marshall, Cooley, Alexander and Moore 1996) reported finding it in extreme southern MI (intensive searching found it only in the southern portions only of the southern tier of counties. They were not willing to say whether this represented a range extension or the species being missed earlier). I first found it in Marshall County, Indiana, and DuPage County, Illinois, in 2010, but suspected I had heard it earlier. They are scattered across the southern half of DuPage.

Slightly musical conehead (N. exiliscanorus)

Slightly musical Max Wet b

Slightly musical conehead SINA map. This does not yet reflect our finding them in Porter and Marshall Counties, Indiana, in 2012.

Slightly musical conehead SINA map. This does not yet reflect our finding them in Porter and Marshall Counties, Indiana, in 2012.

Original range sources: Hebard 1934 (northern limits indicated as Tower Hill in south central Illinois, and New Harmony in Indiana). McCafferty & Stein 1976 (“In Indiana it is known only from heavy thickets and grasses along the Ohio River”). Gideon Ney, Nathan Harness and I, seeking slender coneheads, found this species at the Indiana Dunes National Lakeshore in 2012, and I found it in Marshall County as well.

Marsh conehead (N. palustris)

Slightly musical conehead SINA map. This does not yet reflect our finding them in Porter and Marshall Counties, Indiana, in 2012.

 

Marsh conehead SINA map. This does not yet reflect our finding them in Porter County, Indiana, in 2012.

Marsh conehead SINA map. This does not yet reflect our finding them in Porter County, Indiana, in 2012.

Original range sources: Hebard 1934 (“Lawrenceville and Carbondale are northern and western limits respectively for palustris…It is probably confined to the southern portions of Indiana and Illinois.”). McCafferty & Stein 1976 reported Tippecanoe County as the northern known extent. Ney, Harness and I found this species to be common at Indiana Dunes National Lakeshore and present in the state park.

General Points

Most of these range extensions are from south to north. Exceptions are Roesel’s katydid (east to west) and the broad-winged tree cricket (spreading south as well, according to SINA coordinator Tom Walker).

I do not know whether any other of these species likewise are spreading south or in other directions.

Some of these are clear range expansions, as they are species which were well known at the time of earlier studies, and now have become abundant beyond the range as then drawn: broad-winged tree cricket, jumping bush cricket, Roesel’s katydid, and round-tipped conehead.

The others have a spottier distribution, or may not have been as well known then, and so might have been missed by earlier researchers: handsome trig, swamp cicada, slightly musical conehead, and marsh conehead.

As for the possible connection between these range extensions and climate change, Gonzalez (2012) mentioned a calculation, based on work in Gonzalez et al. (2010), indicating that the region’s climate has undergone a temperature change equivalent to a southward shift in latitude of 100km in the 20th century. This is consistent with the magnitude of many of these observed range changes.

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