Tying a Knot on 2020

by Carl Strang

I know of no one who is sad about putting the year 2020 in the rear-view mirror. I have posted my research highlights for the year already, but find some miscellaneous photos remain that will fill out the story. As I detailed in earlier posts, ditch hopping was an important activity through the summer.

Another view of a drainage ditch in Kankakee County

I paid a couple visits to the Chicago Park District’s Big Marsh for the first time this year. Of greater interest to me than the wetlands was an area of sparse vegetation in the eastern part of the park.

When I run across scenes like this I automatically want to check for unusual grasshopper species.

Indeed, I found my third population of pasture grasshoppers (Orphulella speciosa) for the region here, and a second population of Kiowa rangeland grasshoppers (Trachyrhachys kiowa) for Cook County.

A pasture grasshopper at Big Marsh Park
One of the Big Marsh Kiowas

There also was a strikingly marked nymph.

The white spots stand out. I don’t have a species ID.

I made a day trip to the Nachusa Grasslands, west of my study region. The area has a nice variety of singing insects.

One of the few Texas bush katydids (Scudderia texensis) I encountered in 2020. This Nachusa female provided a nice photo of her sharply bending ovipositor.

In my home county of DuPage, West Chicago Prairie Forest Preserve provided some highlights.

The prairie cicada (Okanagana balli) population at West Chicago Prairie continues to respond to the Forest Preserve District’s restoration efforts.
These small cicadas are active for only a brief time in the early summer.

Later in the season I made a slogging trudge to a remote corner of West Chicago Prairie, hoping to find rare wetland katydids.

There were no new species, but a separate location for long-tailed meadow katydids (Conocephalus attenuatus), including this male, within the preserve.
This West Chicago Prairie female’s ovipositor, fading out of focus in the dim light that day, illustrates how the species gets its common name.

Finally, I continued both monitoring and restoration efforts at St. James Farm Forest Preserve.

Typocerus velutinus is one of the more common longhorn beetles in DuPage County.
While gathering Joe-Pye weed seeds to spread in our cleared area, I found this mating pair of walking sticks (Diapheromera femorata).

Clearly 2020 had much to offer, after all, and I hope for plenty of new encounters in 2021. Happy New Year to you.

Ditch Hopping: Woodland Meadow Katydids

by Carl Strang

As I started seeking northern mole crickets in rural ditches at night, I realized that ditches and streams are oases of habitat winding through the biodiversity wastelands of corn and soybeans in large portions of the Chicago region. I started checking ditches during the daytime. The biggest hit came early on, when I discovered woodland meadow katydids beside a ditch in southeastern Kendall County, Illinois. I had dismissed expectations in that county for the species, so this was a big surprise.

Woodland meadow katydid (Conocephalus nemoralis)

The ditch seemed an unlikely location for that katydid, which I had found previously only at woodland edges. A single small tree was the only nearby woody plant.

One of the Kendall County locations for woodland meadow katydids

This proved to be a common pattern, however. As I added county after county to the list of those where I have found woodland meadow katydids, sometimes there were woodland edges adjacent to the ditches but sometimes there was little woody vegetation to be found.

Updated site map for woodland meadow katydids

I was frustrated in LaPorte County, Indiana, and Berrien County, Michigan. I later learned that woodland meadow katydids also can inhabit dune edge habitats along Lake Michigan, so I will seek them there in 2021.

Ditch Hopping: Northern Mole Crickets

by Carl Strang

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.

Japanese Burrowing Crickets Spreading Rapidly

by Carl Strang

The Japanese burrowing cricket is, as the name suggests, an oriental species that was accidentally introduced to this country at one or more coastal ports. They have spread out from there, and I first encountered them in the Chicago region at Bendix Woods, a St. Joseph County park, in 2014.

Japanese burrowing cricket, Velarifictorus micado

Since then I have found them increasingly at sites throughout the southern portion of the Chicago region.

Counties of the Chicago region, with years when I first observed Japanese burrowing crickets in each.

Fulton County, at the southeast corner of the region, is the most remote from my home, so I don’t go there often. I rather imagine that Japanese burrowing crickets are in the city of Rochester, at least.

Note that I added 7 counties this year. This is in part because they are increasing in the region, and in part because I encountered them frequently while ditch hopping (more on that in later posts). Rural drainage ditches may be major dispersal corridors, along with human-assisted transport in landscape and building materials. The crickets also may fly to expand their range, but this possibility remains speculative.

Japanese burrowing crickets have been ubiquitous and abundant in Indianapolis for years. Last year I found them to be common in Rensselaer, Indiana, one of the southernmost cities of the Chicago region. There is every reason to believe that they will become abundant through most or all of the region over the next decade. They thrive in loose landscaping stone and in lawns, which are not prime habitat for our other members of the field cricket group, so it is possible there will be little effect on our native species.

Here is the most common calling song of the Japanese burrowing cricket:

Perhaps less commonly heard is this alternative:

A New North for Jumping Bush Crickets

by Carl Strang

We are getting into the latter part of the singing insects season, and I have some catching up to do here. This time, just a quick note to update the northward advance of jumping bush crickets. This species has been spreading more rapidly than any others of our native singing insects. The Fox River has been my focus in recent years, as it appears to be a corridor they are following. The next county I expected them to reach was McHenry, and this year for the first time I found a population in the city of Algonquin in southern McHenry County.

Jumping bush cricket

I first heard jumping bush crickets in southern Kane County (immediately south of McHenry) in 2012. They have covered the 30-mile length of that county in 8 years. If they continue at that rate, they will reach the Wisconsin border in 6 years or so.

The red dot indicates the new location in McHenry County.

Their songs remind me of little bells tuned to slightly different pitches, and are loud and easy to hear as the males sing from hidden perches in trees, vines and shrubs. Here is a recording featuring jumping bush crickets:

Editorial: Are There Any Good Cops?

by Carl Strang

This is a nature blog, but from time to time I have felt the need to insert an editorial. This is one of those times. I am an ecologist, trained and practiced in seeing connections among things. The city of Kenosha, Wisconsin, is in my study region and I have picked up singing insect county records in its parks. It saddens me to think that Kenosha may come to be thought of with the same negative connotations that saddled Selma and Montgomery, Alabama, in my youth.

The title of this post is deliberately provocative. Frequently I have seen the opinion expressed that bad cops who shoot to kill innocent civilians simply because they are black are a minority, that most cops are good cops. But I feel that at this point in our history we need a redefinition of what constitutes a good cop. Is it enough to be a police officer who does not grab any opportunity to kill a black man? Consider what happens in the wake of the headlines. Police unions close ranks in support of the officers who commit these killings. Seeing this, attorneys general do not press charges. We hear nothing from the supposed “good cops.”

Police officers are human beings. It needs to be acknowledged by all that this means some of them are mean spirited, that some are the manipulative sort who will call upon their “brothers” to support their evil actions. This needs to change. There needs to be a transformation of cop culture so that the ranks recognize and fail to support those few who use the power of their position to do evil. There need to be conversations in police stations, leadership by chiefs, making clear that those who try to use the power of their badge to do wrong will be outcast. Chiefs and veteran officers need to make clear to attorneys general that they need to do their jobs, and the good cops will support them.

It is fair to ask how I, an old white guy, have acted with respect to this issue. From the early times when wrongful killings of black men and women by white cops came into the news, I have imagined myself in the position of a black man and realized how this can make them fearful. I have felt profound respect for the patriotism and restraint of African American culture, given the history of slavery, lynchings, segregation and racism. My response has been on the personal level, smiling, waving, and greeting those I meet with a special emphasis on those of other races. I recognize that I am a symbol, and I try to create a positive, supportive moment of encounter to counterbalance the frowns and rejections.

It extends beyond race. I am a runner, and I love the girl runners. I love the way women have embraced my sport, and I am happy when I encounter a woman on the trails. As always, I wave and smile. Often the greeting is pointedly ignored. I understand this and admire the courage of a woman who goes out alone for a run, knowing how women runners have been sexually assaulted and killed by evil men. I recognize the fear and am saddened by it.

I suppose my behavior could be labeled racist or sexist. Yes, I recognize the race, gender, and age of every person I meet. Over the years I have learned through experience that differences of gender and race have little meaning for me, however. Each individual is worthy, and differences of race, gender, sexuality and so forth are insignificant compared to the uniqueness of each person. It is our behavior and regard of one another, not abstractions or stereotypes of race, gender, etc., that matter.

What about demonstrations? The motivation to express opposition to these wrongful killings is understandable, but they have a counterproductive component. Some express their outrage through violence. Even if only a few behave in this way, it supports the notion that the demonstrations are against the police as a whole, setting up an us-versus-them framework so that police sometimes respond in force, feeling unified in supporting one another and justified in using violence even against the peaceful protesters.

The opponent here is not the police, but something more abstract: a cultural tradition of tribal identity, loyalty and brotherhood. Those are strong bonds, but they must be made apparent as weaknesses being exploited by wrongdoers. They must be revealed as secondary to the reason we have police in the first place: to serve and protect. Serve. Protect. Serve and protect the public first, and fellow police officers second when the two come into conflict.

Flagging in the Heat

by Carl Strang

On Saturday I completed my survey of 2020 periodical cicada reproduction in the Chicago suburbs. I focused on 18 suburban cities where I had observed wave chorusing, mapping out walking routes where I counted the flags that indicate where female cicadas deposited eggs in tree and shrub twigs. Altogether I walked 33.4 miles on hot afternoons, but the main physical challenge was the stiff neck I developed from constantly looking up into the trees. I will need to consult with periodical cicada specialists to be sure, but it seems to me that the numbers support a persistent, parallel splinter regional population that will continue to appear 4 years ahead of each major emergence.

Here I will share two sets of data. First, the highest numbers of flags in single trees.

Map of Chicago suburbs I surveyed for periodical cicada reproduction. Numbers indicate the highest count of flags in a single tree. Flags are withered twig ends that result from female cicadas inserting their eggs and cutting off the twig’s vascular system.

The high count of 33 was in Brookfield. I was walking residential streets, so my counts are transects rather than area surveys. The next map gives average numbers of flags per 100 meters. I used that number as the divisor because I often observed 1-2 wave choruses per block while driving earlier in the season, and 100m represents a middle-of-the-road block length.

Average counts of flags per 100m in Chicago suburb survey routes.

The highest counts of 10.5 and 9.1 are in LaGrange and Western Springs, respectively. These counts are conservative: I usually could not see all sides of a tree, canopies blocked part of the view, and to an unknown but certain degree flags had fallen to the ground and were removed by homeowners (this takes away some eggs, but there are others in the twig above the break).

Flags fallen to the ground at Madison Meadow Park, Lombard. In a residential yard these likely would have been removed before I could count them.

This fallen flag carried some eggs, leaving others still on the tree. Sugar maples were a popular choice by female periodical cicadas.

In addition to these transects in the cities, there were isolated parks and sites worth considering. At Pioneer Park Forest Preserve in Naperville, a single isolated non-wave chorus tree produced 7 flags spread between two trees. A similar case at Cook County’s Bemis Woods produced 18 flags. A park in Downers Grove had 37 flags. Other forest preserves had enough flags to suggest that their local off-year populations will continue: 22 at Lyman Woods, 13 at Greene Valley, and though I was disappointed by the size and timespan of the wave chorus at Wood Dale Grove, there were well over 30 flags there.

Tree with flags at Pioneer Park

First Flags Over Brookfield

by Carl Strang

Cicada specialist John Cooley taught me a new term: flagging. This refers to dead and broken twig ends on trees and shrubs where periodical cicadas have placed their eggs. Mama cicada slits the underside of the twig in several places and injects her eggs. This impedes water flow, and with circulation cut off the leaves turn brown. The cuts weaken the twig, and it may break partly and bend down, producing a “flag.”

Now that the periodical cicadas are done singing in many places and nearly so in others, it is time to start looking for these flags. They will provide the best measure of how this off-year emergence may continue for another generation. On Tuesday I started in Brookfield, the first place where I heard a full wave chorus of singing males.

I soon found a tree with many flags.

This tree was in the same place where I found that initial wave chorus.

The brown, drooping flags stand out against the green foliage. This prunes the tree a bit but will not cause significant harm. I saw many trees with one or two flags, but only the two in the photos had many. I expect to see more of them the next time I check.

John said that dry weather and thunderstorms enhance flag formation. A lack of water flow enhances the twig-end drying, and the buffeting winds of storms partially snap the weakened twigs. I heard no singing cicadas in Brookfield, and so this is the very beginning of this process. On the way home I swung through northern Hinsdale, another area that had abundant wave chorusing at the peak. There still were many small non-wave choruses, so it was not surprising that I saw only a couple flags during the drive-through. I am hopeful that flagging will develop over a period of weeks, allowing me the time needed to get a good assessment of periodical cicada reproductive success across the Chicago area this year.

Periodical Cicada Update

by Carl Strang

The 2020 periodical cicada emergence in the Chicago region has reached its peak and is winding down. It has been a mad and sometimes confusing scramble to collect data, but an overall complex picture has emerged. First, a wide-angle look:

Collected observations of periodical cicadas in 2020. White dots indicate towns or parks in which at least one or a few cicadas were documented. Yellow dots mark countable numbers, i.e. from one spot you could hear multiple cicadas singing. Orange dots mark small choruses (though sometimes occurring over large areas), in which the cicada songs were blended to the point where individuals no longer could be picked out, but the choruses were not organized. Red dots mark areas with full choruses, formed into periodic waves of song, loud and with both species audible.

These assessments of numbers are conservative. Many of the white dots are taken from iNaturalist submissions based on a photo of one insect. It is possible that in many cases the peak numbers were above that level, some possibly all the way to full wave chorusing. Also, some of the orange dot communities were assessed before the peak time and may well have developed full wave chorusing later. I visited nearly all the red dot communities myself, walking or driving to get some sense of the area involved. Several to many square blocks were typical here, and often I observed mating pairs and females laying eggs or saw lines of eggs in twigs. The wave chorusing lasted up to two weeks in these places.

Cassin’s 17-year cicada laying eggs in Mokena, Will County

Periodical cicada eggs in winged euonymus twig, Woodridge, DuPage County

Areas with wave chorusing generally were imbedded within a matrix of lower level numbers. Overall, the Chicago suburbs saw the emergence of enormous numbers of periodical cicadas. Apart from the specific observations of mating insects, egg-laying females and eggs in twigs, there is reason to believe that this is an on-going, reproducing population separate from the main regional emergence that next will occur in 2024. That reason is that these suburban neighborhoods have relatively few predators. The reason periodical cicadas have been so successful is understood to be that they overwhelm the many species of consumers that eat them. Suburban residential communities cover huge areas and are ecologically depauperate in that they are reduced to mowed lawns and trees, with some shrubs and herbaceous plantings that typically are non-native and therefore support few insects. That results in low numbers and diversity of predators compared to what the remnant forests harbor.

Example of habitat in River Forest, Cook County, a wave chorus area

I simply did not observe predators beyond the rare crow, territorial robins and usual densities of other species typical of these neighborhoods. I suspect that not only has this population split off from the main emergence, it has been building in numbers with each generation (I use the singular here because I am referring mainly to the Cassin’s 17-year cicada. Though Linnaeus’s 17-year cicadas were present in all the red dot areas, their numbers are more difficult to assess, and the only evidence I have of their reproducing is a single submitted photo of a female laying eggs).

Linnaeus’s 17-year cicada laying eggs in southeastern DuPage County. Photo by Leslie Bertram, used with permission.

I do not want to give the impression that predation wasn’t occurring. There were plenty of signs like this. The numbers removed simply were not making a dent in the mass choruses.

Now I want to focus on DuPage County, because I have the background of a detailed study of the cicadas’ history and their 2007 major emergence there.

This is my working map of the periodical cicada emergence of 2007, with superimposed 2020 observations. Pink areas mark the extents of the 2007 emergence areas. Colored dots represent the same levels of 2020 cicada numbers as in the regional map above.

If you find this image bewildering, I welcome you to the club. The emergence pattern was so spotty and localized that I cannot comfortably mark out large uniform areas. Dots are expanded either along my survey driving routes, or to cover the size of areas more expansively explored. To get a sense of the biological significance, try to tune out the white and yellow dots, as those locations had few enough cicadas that predators would have had no trouble wiping them out.

Again the red areas had so many cicadas that I had no trouble finding examples of mating or egg laying. Red areas adjacent to one another could be combined, as the habitat among them was uniform and continuous. This is particularly true of the cluster of red areas in the southeastern quarter of the county where the cities of Downers Grove, Clarendon Hills, Westmont and Hinsdale blend their similar residential neighborhoods. This area in fact continues east across the Tri-State highway corridor into Cook County’s adjacent city of Western Springs.

I am especially interested in the areas with loud, extensive wave chorusing that are outside the 2007 emergence regions. I will be referring to my detailed notes when I return to these locations in 2024.

The big emergences were in residential areas. Forests were a different story. For the most part, forested areas did not rise above the countable numbers of cicadas. I admit to being disappointed by what I observed in Wood Dale Grove and Salt Creek Park Forest Preserves and their connecting and surrounding residential areas. Both species emerged in both preserves, but never got above the countable level at Salt Creek Park. In part of the forest at Wood Dale Grove there was an area of a few acres in which wave chorusing developed, but it was in only part of the forest and lasted at most 3 days before collapsing to countable numbers again. I draw consolation from this result because it supports my suspicion that forests harbor numbers and diversity of predators that contrast with the expanses of residential communities that form the Chicago suburbs. Though the residential areas surrounding Wood Dale Grove and Salt Creek Park resemble those that had large and sustained cicada choruses, it would be easy for predators to spill out of the preserves and consume cicadas emerging in the surrounds. Cicada specialists may be interested to know that I did check Raccoon Grove Forest Preserve in Will County. I heard only two singing Cassin’s males there.

I have one more step this year, and that is to return to many of these places and look for egg damage to trees and shrubs. This will better assess reproductive success than the several but scattered observations mentioned above. Then it will be a wait of four years until the big show, and I wonder if there will be any peculiarities in the spots where there were mass emergences this year.

Cicada Emergence Stages

by Carl Strang

The 2020 emergence of periodical cicadas in northeast Illinois is under way now. It has taken a while to get going and is running about two weeks behind the last main emergence in 2007. People have sent or posted reports from 28 towns or preserves so far in Cook, DuPage, Lake and Will Counties. I have begun to visit places where significant numbers of the insects have been reported.

The pattern is reminiscent of what we observed in 2007. A few individuals come out of the ground at first, then a few days later there may be a night that brings out many. It takes them a few days of recovery before the males begin to sing, few or countable numbers of Cassin’s 17-year cicadas in most places. So far only some of the more open residential areas have reached this stage. Forests lag behind because the trees retard the warming of the soil which triggers the cicadas’ emergence.

This Cassin’s 17-year cicada was the first I found in Wood Dale Grove Forest Preserve, the June 4 date well after they had begun appearing in open residential areas.

Where there are good numbers of cicadas, small choruses may develop in which there are too many Cassin’s to count. Such has been the case in 5 communities so far. The ultimate step, which to date I have found in only one spot in southwest Brookfield, has numbers of Cassin’s 17-year cicadas chorusing so loudly that it can be nearly painful to stand under them. Their chorusing produces waves of loud then softer sound on a regular rhythm, and they are joined by the second species, Linnaeus’s 17-year cicada, whose songs add a high-pitched overtone to the Cassins’ buzzing quality. When visiting that place in Brookfield I saw many cicadas on the ground, many nymphal skins, many holes in the soil, and a pair of mating Cassin’s. I saw a crow eating a cicada, but there may be too few predators in these residential neighborhoods to have much impact on this off-year emergence.

Many emergence holes and empty nymphal skins marked the high density area in Brookfield.

Mating pair of Cassin’s 17-year cicadas in Brookfield on June 5

I made the following sound recording in the same area. The surrounding Cassin’s choruses wash out the focal one somewhat, but you may be able to pick out the 6 waves of high volume spread evenly here (5-6 seconds between peaks in this 32-second recording). Also, listen for a few Linnaeus’s “pharaoh” calls along the way. They are not coordinated with the Cassins’ waves.

A visual rendition of the recording

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