Wing Length and Song Quality

by Carl Strang

In a preliminary way I have begun to look at the question of how wing length affects song production in Roesel’s katydids. This seems pretty esoteric at first glance, but it has personal practical application, as I will explain. Roesel’s katydid is a European import which first appeared in the late 1940’s around Montreal, Quebec. They since have spread to the point that they can be found throughout northern Indiana and Illinois, and at least much of Michigan and Wisconsin. They come in a variety of wing lengths:

Short, as in this female in Kendall County, Illinois…

Short, as in this female in Kendall County, Illinois…

Intermediate, as in this male recently photographed at St. James Farm…

Intermediate, as in this male recently photographed at St. James Farm…

And long, as in this male at Blackwell Forest Preserve.

And long, as in this male at Blackwell Forest Preserve.

Researchers have noted that long-established populations in the European homeland are composed almost entirely of shorter winged, therefore flightless, individuals. The frequent observation of long-winged variations here has fostered the speculation that this has to do with dispersal as Roesel’s katydid expands its North American range. That may be true in the long run, but the edge of that range is far from the Kendall and DuPage County locations of the above individuals, and long-winged ones remain common.

Since I began my study of singing insects in 2006, I have been disappointed to find that each year my ability to hear the buzzing song of male Roesel’s diminishes. Furthermore, on hot days I can hear them fine in the cooler morning hours, but at some point I can no longer hear them. The pitch of their song rises with temperature, until it goes above my audible range. The SongFinder pitch lowering device proves they still are singing (incidentally, the buzz is steady when I hear it unaided, but through the SongFinder it has a superimposed vibrato which becomes more rapid with increasing temperature. This doesn’t happen with other singing insects).

Over the winter the question came to me whether the wing length of the males affects their song. Next year, retirement will allow time to pursue this in more detail, but for now I have an afternoon’s observations that seem to support a difference. I was following trails through north Blackwell’s meadows, occasionally listening with the SongFinder. The temperature was mid-70’s F. Many Roesel’s were singing, but I would not have known this without the device. Then I heard one unaided. I sought it out, and it was long winged. The same was true of two other individuals (the third is the one in the above photo).

Next year I want to make recordings of individuals with different wing lengths, and compare the parameters of their songs. Perhaps the analysis also will give some idea why the pitch-altered song has that vibrato. I want to think, too, about the possibility that there is an evolutionary dynamic going on here. If the song is different among males with different wing lengths, does that matter to females? If so, how? For instance, if long-winged females prefer long-winged males, and short-winged females prefer short-winged males, this could retain genes for long wings in the population for a reason other than dispersal advantage.

 

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Centennial Bioblitz

by Carl Strang

The Forest Preserve District of DuPage County’s Centennial Bioblitz started under rain and somewhat cool temperatures last Friday night. We sent off the first plant survey teams and frog monitors, and a small bird team went out, but the rain continued. As the darkness built, it became clear that light stations for insects would get limited results. I gathered the group who had come for one of the public programs, and Purdue University entomologist Jeff Holland explained that the dripping water would explode their hot bulbs. We set up my ultraviolet light, and Jeff led the team into the forest at St. James Farm.

Dr. Holland examines a beetle one of the participants found.

Dr. Holland examines a beetle one of the participants found.

The kids had a great time catching fireflies, and finding insects and other creatures active in the rain.

Classic kid nature fun was had by all.

Classic kid nature fun was had by all.

When we stopped by the light on the way back, we found a few beetles and small moths, but the sheet mainly held a host of mosquitoes.

Amid hundreds of floodwater and other common mosquitoes, there were a few huge ones.

Amid hundreds of floodwater and other common mosquitoes, there were a few huge ones.

Late into the night, and much of the next day, my focus was on support and organizational work, but I did make two brief field excursions and added a few species to the count on the four preserves of the bioblitz survey.

This green darner showed off its bullseye face paint.

This green darner showed off its bullseye face paint.

Halloween pennants have been common around the county in the past week.

Halloween pennants have been common around the county in the past week.

I recognized the chickweed geometer from my preserve monitoring work at Mayslake.

I recognized the chickweed geometer from my preserve monitoring work at Mayslake.

Roesel’s katydids had begun to sing in the previous week. This mature male has short to medium-length wings.

Roesel’s katydids had begun to sing in the previous week. This mature male has short to medium-length wings.

This coneheaded katydid nymph at the edge of the parking lot meadow was large enough, and its cone the proper shape, to be a sword-bearing rather than round-tipped conehead.

This coneheaded katydid nymph at the edge of the parking lot meadow was large enough, and its cone the proper shape, to be a sword-bearing rather than round-tipped conehead.

The botany teams no doubt caught this one, but I couldn’t resist photographing these starry Solomon’s plume fruits at Blackwell.

The botany teams no doubt caught this one, but I couldn’t resist photographing these starry Solomon’s plume fruits at Blackwell.

Our rough estimate at the end of the bioblitz was 900 species documented for the four preserves. I will report more detailed numbers when we have them.

 

Early Season Survey: North

by Carl Strang

On Tuesday of last week I drove north to seek early season singing insects in 5 Wisconsin and northern Illinois counties. I was prepared to camp overnight, but with rain in the forecast for the next day I was happy to complete the run in one day.

My first stop was Middlefork Savanna in Lake County, Illinois.

My first stop was Middlefork Savanna in Lake County, Illinois.

Spring field crickets were singing, but vegetation still was wet from an overnight rain, and I was lucky to spot this greenstriped grasshopper to give me that county record.

Spring field crickets were singing, but vegetation still was wet from an overnight rain, and I was lucky to spot this greenstriped grasshopper to give me that county record.

From that point it was rapid-fire site hopping, and I didn’t take many photos.

An exception was this Roesel’s katydid nymph at Wadewitz Nature Camp, a Racine County (Wisconsin) Park.

An exception was this Roesel’s katydid nymph at Wadewitz Nature Camp, a Racine County (Wisconsin) Park.

Wadewitz has extensive grassy meadows, and the biggest surprise of the day was not finding displaying greenstriped grasshoppers in the warm sunny mid-day. Ultimately I was able to find both spring field crickets and greenstripeds in all 5 counties, but several stops were required in some cases.

Singing Insects in Transition

by Carl Strang

We are at a point in the season where the spring-singing insects are finishing, and the early summer brings new voices to the chorus. Green-striped grasshoppers seemed to tail off rapidly in their crepitating flights this year. I have heard very few in recent weeks.

The male green-striped grasshopper usually is brown. He’s the one who does the displaying.

The male green-striped grasshopper usually is brown. He’s the one who does the displaying.

The object of his displays usually is green, and a bit bigger than him.

The object of his displays usually is green, and a bit bigger than him.

Roesel’s katydids rapidly are increasing the number of buzzes they are contributing to the meadows and prairies.

Note the blur in the wings as this short-winged Roesel’s katydid sings. Some individuals have much longer wings.

Note the blur in the wings as this short-winged Roesel’s katydid sings. Some individuals have much longer wings.

Over the weekend I heard first songs from three additional species: Linne’s and dog day cicadas, and the gladiator meadow katydid.

This was one of several gladiators singing beside the Regional Trail in south Blackwell Forest Preserve Saturday evening.

This was one of several gladiators singing beside the Regional Trail in south Blackwell Forest Preserve Saturday evening.

Those Tibicen cicadas, especially, characterize the sound of summer for me.

Eagle Marsh Bioblitz

by Carl Strang

Each year the Indiana Academy of Sciences selects a site within that state for a bioblitz. This past weekend’s was my third, and it always is a great way to kick off the field season. The location this year was Eagle Marsh, on the western fringe of Fort Wayne.

A large open barn in the center of the site made for a good headquarters.

A large open barn in the center of the site made for a good headquarters.

Support for the visiting scientists and other volunteers was excellent. Here, the morning’s adventures are shared over box lunches on Saturday.

Support for the visiting scientists and other volunteers was excellent. Here, the morning’s adventures are shared over box lunches on Saturday.

The objective of a bioblitz is to find as many species of organisms as possible in a brief period, usually 24 hours. Scientists who specialize in different taxa lead teams that explore the site. Eagle Marsh is dominated by wetlands, as the name implies. In fact it sits on the boundary between two watersheds, the Great Lakes to the north, and the Mississippi River drainage to the south.

This fence is intended to block Asian carp from reaching the Great Lakes when the rivers flood. It soon will be replaced by a more reliable berm.

This fence is intended to block Asian carp from reaching the Great Lakes when the rivers flood. It soon will be replaced by a more reliable berm.

The site largely is a restoration project begun in 2005, though some teams found surprising diversity in parts of the preserve. My singing insects team was limited by the early date. We found a grand total of 3 species.

This Roesel’s katydid nymph was one of a small cluster we found on an elevated bank.

This Roesel’s katydid nymph was one of a small cluster we found on an elevated bank.

This bioblitz invited members of the public to assist those scientists open to such participation. I was delighted to have a team, for a change, and we enjoyed all the organisms we were finding.

Northern leopard frogs were abundant, a sign of how rapidly the wetland is improving in quality.

Northern leopard frogs were abundant, a sign of how rapidly the wetland is improving in quality.

Peck’s skipper was one of a number of butterfly species we observed.

Peck’s skipper was one of a number of butterfly species we observed.

Jeff Holland’s Purdue University entomology team always provides a highlight with their beetle-drawing lights.

1000 watts of power.

1000 watts of power.

Helpers collect some of the insects that fall to the sheets below.

Helpers collect some of the insects that fall to the sheets below.

Here is what they were seeing.

Here is what they were seeing.

Congratulations to Betsy Yankowiak and the Little River Wetlands Project team for a job well done.

Betsy presented an overview of the area’s geology for interested participants.

Betsy presented an overview of the area’s geology for interested participants.

First SFC’s

by Carl Strang

On Sunday afternoon, during a bike ride through Fermilab, I heard the first spring field crickets of the year. They had just begun, as there were only 3 of them. This is the third earliest date I have heard them in DuPage County, a little surprising given the late spring, though the deep snow that covered the ground most of the winter certainly provided the nymphs with protection. If a larger population survived, some statistical outliers could be starting up earlier than otherwise would be the case.

Cheating a little here: this is a fall field cricket female, but that species is physically identical to its spring sibling species.

Cheating a little here: this is a fall field cricket female, but that species is physically identical to its spring sibling species.

Apart from such uncommonly encountered critters as sulphur-winged grasshoppers and spring trigs, the next common singing insects to mature should be the predaceous katydids (Roesel’s katydid and the protean shieldback), and gladiator meadow katydids. By then I hope that the spring field crickets will have built numbers to the point where I can finish my county survey of their distribution.

Sound Ideas: Early Season Katydids

by Carl Strang

The start of the singing insect season still is a couple months away, but among the early species will be the three katydids I am featuring today. They are relatively hardy, hatching very early in the spring and developing quickly. Two of them, Roesel’s katydid and the protean shieldback, are known as predaceous katydids, and their dietary focus on animals is what allows them to get going so early. The gladiator meadow katydid is the earliest of its species group to hatch, and so the earliest to begin singing. The meadow katydids are generalists, and the gladiator probably has a greater proportion of animal foods in its diet than the others. Roesel’s katydid is a European species, introduced in the Montreal area and spreading south, east and west from there.

Roesel’s is the only katydid in the Chicago area with a color pattern anything like this.

Roesel’s is the only katydid in the Chicago area with a color pattern anything like this.

Its song is a long, fast, constant buzz:

I am at an age where I have a little more difficulty hearing this one each year. The pitch rises with temperature, and on a hot mid-day I now need the SongFinder pitch-altering device to hear individuals that are audible in the morning and late afternoon.

The protean shieldback, like Roesel’s katydid, is a species of the meadows, but also is common in brushy areas and open woodlands.

Protean shieldback female. This is a relatively heavy-bodied katydid

Protean shieldback female. This is a relatively heavy-bodied katydid

Its song is an extended buzz, but has much more of a slower, rattling quality than Roesel’s song.

It is not as loud as it may seem from the recording, but is not really difficult to hear. The protean shieldback begins singing in mid- to late afternoon, and continues into the night.

The gladiator meadow katydid is similar in appearance to other large meadow katydids.

This photo shows why the meadow katydids once were known as “long-horned grasshoppers.”

This photo shows why the meadow katydids once were known as “long-horned grasshoppers.”

The gladiator meadow katydid’s variation on the generalized tick-and-buzz meadow katydid song pattern de-emphasizes the tick portion. I often don’t notice ticks at all, though they may be softly produced more often than I suspect, as in the following recording:

The buzz is similar in quality to the protean shieldback’s song, but it is shorter in length, rhythmically produced, and the volume rises at the end.

Dispersal Ability

by Carl Strang

In order for us to understand insects well enough to know which ones need the most attention in conservation, there are some pieces of information we need: how abundant they are, how broad or narrow their habitat needs, their reproductive potential, and their dispersal ability. The first two items are readily obtained in the course of a regional survey such as I am conducting for singing insects in northeast Illinois and counties in neighboring states. Reproductive potential has been studied to some extent and can be found in the literature for some species. Dispersal ability is a critical point that is not well studied as far as I can tell, and so it is good to take advantage of observations that reveal which species spread easily, and which ones do not.

Over the past two weeks I spent much time in the St. Joseph Hospital in Mishawaka, Indiana, where the medical professionals saved my mother’s life.

The hospital was built 3-4 years ago, and is surrounded by extensive areas planted mainly in native prairie plants.

The hospital was built 3-4 years ago, and is surrounded by extensive areas planted mainly in native prairie plants.

Occasionally I took walks along the paths, or made observations while arriving or departing. The species present in the plantings can be regarded as ones with high dispersal ability. These included field crickets (I cannot be sure which, as this was the cusp between the spring and fall field cricket seasons), striped and Allard’s ground crickets, Carolina grasshoppers, Roesel’s katydids, and a sword-bearing conehead. All of these are regionally abundant, and fairly broad in their habitat (dry to mesic mixes of grasses and forbs). Three have good flying ability (in the case of Roesel’s, there are long-winged individuals as well as medium and short-winged ones). Field crickets and the ground crickets can take advantage of their regional abundance and tendency to hop and walk over land. One limitation here is that I was only able to make observations over a brief portion of the season.

If I had to point to the weediest singing insect in our region, I’d have to say it’s the striped ground cricket, which is the quickest to appear in a new site.

Bioblitz Species Hunt

by Carl Strang

Yesterday I introduced last weekend’s bioblitz at Connor Prairie in Indiana. My focus as a bioblitz participant is on singing insects, of course, but those are few early in June, even as far south as Indianapolis. Not to worry, though. There were teams focusing on many groups of organisms, but others had no specialists to address them, so I enjoyed filling in where I could. Odonata were one such group.

Twelve-spotted skimmer

Twelve-spotted skimmer

Powdered dancer

Powdered dancer

After much pondering, I concluded this was a female cobra clubtail. Indiana has a similar species, the handsome clubtail, but certain details ruled it out.

After much pondering, I concluded this was a female cobra clubtail. Indiana has a similar species, the handsome clubtail, but certain details ruled it out.

For instance, the C-shaped line at the top of the side of the thorax is connected, and apparently too thick for a handsome clubtail.

For instance, the C-shaped line at the top of the side of the thorax is connected, and apparently too thick for a handsome clubtail.

I also saw three bumblebee species.

Bombus fervidus was an easy ID.

Bombus fervidus was an easy ID.

There was a butterfly team, but I took advantage of photo ops that presented themselves.

Variegated fritillary

Variegated fritillary

Nevertheless, my main interest was singing insects. I found 4 species, and botany team leader Scott Namestnik added a 5th.

Green-striped grasshoppers were common, as were spring field crickets.

Green-striped grasshoppers were common, as were spring field crickets.

I saw a single sulfur-winged grasshopper. Scott ran across a pocket of Roesel’s katydid nymphs. Connor Prairie is about even with the Crawfordsville area where I found Roesel’s a couple years ago. So far, none have turned up farther south in Indiana.

The final species is worth a blog post all its own (to be continued).

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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