Making a Case 2: Prairie Meadow Katydid

by Carl Strang

After more than ten years of study, I still have not found several species of singing insects that historically were known in the Chicago region. One of these was the prairie meadow katydid, one of the smaller members of its group. On August 16, Wendy Partridge and I were checking out the bike trail near the nature center at Illinois Beach State Park. Through the SongFinder, which allows me to hear high pitches, I heard faint rapid ticking sounds which, when heard from a closer position, resolved into brief buzzes. They were mechanical and katydid-like rather than cricket-like in quality, and didn’t match anything I had heard before. Wendy, with her unusually good hearing, barely could pick them up. Later, checking reference recordings, I decided they fit the song of the prairie meadow katydid. They were not in the habitat I would expect, however, being in dense vegetation where grasses were mixed with woody plants and forbs, generally shaded. That katydid species has been known to occur in that park, however.

Then on September 27 I caught and photographed a small female meadow katydid in a relatively dry portion of the Gensburg Prairie in Cook County.

Posterior portion of the Gensburg Prairie female.

Posterior portion of the Gensburg Prairie female.

Her color didn’t seem quite right for a short-winged meadow katydid, which is a common species at that site especially in the wetter portions. Studying the photos, and looking back at references, I have decided that she was a prairie meadow katydid. Along the way I looked back at all my photos of short-winged meadow katydids, and found two other individuals that met at least some of the criteria for prairie meadow katydid, one in 2011 at Mayslake Forest Preserve, and one in 2014 in the savanna woodland at Illinois Beach State Park.

The Mayslake female

The Mayslake female

The Illinois Beach State Park female

The Illinois Beach State Park female

All three have curved ovipositors that are slenderer in proportion than in a typical short-winged meadow katydid.

Typical female short-winged meadow katydid

Typical female short-winged meadow katydid

All three also have femoral patterns in which there is a lengthwise pair of lines, as in the short-winged, but have ladders of narrow crossbars rather than being clear between them as in typical short-winged. There is enough overlap in body length, according to references, that it is not a consideration in comparing those two species. The ovipositors are too short, and the femur patterns wrong, for straight-lanced meadow katydid to be a consideration. The Mayslake female is different from the other two individuals in three possibly significant ways: the femoral ground color is green rather than brown or tan, the wings are much longer, and the front of the head does not appear to rise so much (this last being a difference mentioned by W.S. Blatchley in his classic Orthoptera of Northeastern North America, which gives unusually detailed descriptions of species).

Anterior portion of the Gensburg Prairie female. Note the abrupt rise of the tip of the head when viewed from the side.

Anterior portion of the Gensburg Prairie female. Note the abrupt rise of the tip of the head when viewed from the side.

Dorsal view of the Gensburg Prairie female. Blatchley describes the wings of prairie females as covering only one-fourth of the abdomen, two-thirds in short-winged females. Furthermore, the tip of the head, when viewed from above, is relatively wide after an inward bending of its sides, expected from Blatchley’s description.

Dorsal view of the Gensburg Prairie female. Blatchley describes the wings of prairie females as covering only one-fourth of the abdomen, two-thirds in short-winged females. Furthermore, the tip of the head, when viewed from above, is relatively wide after an inward bending of its sides, expected from Blatchley’s description.

Compare this common meadow katydid, with its relatively narrow and straight-sided tip of the head, to the previous.

Compare this short-winged meadow katydid, with its relatively narrow and straight-sided tip of the head, to the previous.

 

Side view of the same male as in the previous photo. Again, note the lack of a rise in the top of the head profile.

Side view of the same male as in the previous photo. Again, note the lack of a rise in the top of the head profile.

Blatchley also believed that prairie meadow katydids occur only in “raw prairie,” a description which applies to Gensburg and Illinois Beach but not to Mayslake. I am inclined to regard the Mayslake individual as an anomalous short-winged meadow katydid, but pending study of museum specimens, am naming the other two prairie meadow katydids.

Recent Indiana Excursions

by Carl Strang

In recent weeks I have visited a few spots in Lake and Newton Counties, Indiana, for the first time. One site in Gary is a state nature preserve with several interdune swales.

Though there are some patches of invasive wetland plants, more than 95% of the area is in native vegetation.

Though there are some patches of invasive wetland plants, more than 95% of the area is in native vegetation.

I had high hopes for this site, which I thought might have stripe-faced meadow katydids and slender coneheads. On an evening excursion and an afternoon one I built a rather mundane species list. In this rainy year it is possible that the target species are present but widely scattered. I want to get in there again in a year when drier conditions might concentrate the species of interest, and also make a larger portion of the site easily navigable.

Willow Slough Wildlife Area in Newton County is a large and diverse area that I barely have begun to explore for singing insects. One target for this year was a roadside ditch lined with native sedges and grasses.

The ditch proved to have only common singing insects, but there was a remarkable concentration of clipped-wing grasshoppers, a non-singing species I have seen in only one other location. This is a nymph; most were adults at this late point in the season.

The ditch proved to have only common singing insects, but there was a remarkable concentration of clipped-wing grasshoppers, a non-singing species I have seen in only one other location. This is a nymph; most were adults at this late point in the season.

I also checked out some narrow drainage swales along an access road closely bordered by forest.

One non-singing species there was the graceful grasshopper.

One non-singing species there was the graceful grasshopper.

Short-winged meadow katydids were abundant, but the population was unusual in that nearly half the individuals were the long-winged variant.

Short-winged meadow katydids were abundant, but the population was unusual in that nearly half the individuals were the long-winged variant.

I wonder if the narrow, constrained habitat has something to do with the oddity of that population.

 

McHenry County Visit

by Carl Strang

On September 3 I drove up to McHenry County, Illinois, to continue my regional survey of singing insects. I spent most of that hot afternoon at the Pleasant Valley Conservation Area.

This county park has some very good woodlands and savannas.

This county park has some very good woodlands and savannas.

The day produced 7 county records.

My first four-spotted tree cricket in McHenry was at Pleasant Valley.

My first four-spotted tree cricket in McHenry was at Pleasant Valley.

A shift to the Hickory Grove Conservation Area produced additional observations, some of them remarkable.

The most unexpected find was a small group of gladiator meadow katydids, still singing weeks after they normally are done.

The most unexpected find was a small group of gladiator meadow katydids, still singing weeks after they normally are done.

The photo shows the characteristic pronotum profile and cerci. The marsh habitat and the distinctive song pattern, with the ticks finishing, rather than preceding, the buzz portion of the song all were consistent with gladiator meadow katydid. The black spots on the abdomen may be signs of a parasite load; could that have delayed the completion of development?

The same site produced this marsh meadow grasshopper.

The same site produced this marsh meadow grasshopper.

The Lyons Prairie and Marsh, administered as part of Hickory Grove by the McHenry County Conservation District, actually is in Lake County. I followed the trail into a portion of the marsh dominated by reed canary grass. In addition to abundant slender and short-winged meadow katydids, I got an intriguing glimpse at a female Orchelimum that might have been a dusky-faced meadow katydid, which I have yet to find in Illinois. I was unsuccessful in getting a better look in that late afternoon, but at some point I need to get back there for a thorough search.

On the way back to the car I spotted this tiny grasshopper. Mature at around 3/8 inch long, it is a non-singing species, the black-sided pygmy grasshopper.

On the way back to the car I spotted this tiny grasshopper. Mature at around 3/8 inch long, it is a non-singing species, the black-sided pygmy grasshopper.

Wetland Concerns

by Carl Strang

A continuing theme in my regional survey of singing insects is the paucity of wetland species. The only one that is present in good numbers in many wetlands is the black-legged meadow katydid. Other species common in wetlands are habitat generalists such as the Carolina ground cricket and short-winged meadow katydid, which don’t truly count as wetland insects. One clear cause of this problem is the loss of high quality habitat to four invasive plant species (purple loosestrife, reed canary grass, common reed, and cattails). All four are capable of completely taking over a wetland, and examples of this can be found for all four. Small numbers of the singing insects mentioned above can be found in such places, but not the other wetland insect species.

This female long-tailed meadow katydid was a rare wetland species holdout in a small pocket of surviving diverse wetland plants surrounded by cattails, reed canary grass and common reed at Waterfall Glen Forest Preserve in DuPage County, Illinois.

This female long-tailed meadow katydid was a rare wetland species holdout in a small pocket of surviving diverse wetland plants surrounded by cattails, reed canary grass and common reed at Waterfall Glen Forest Preserve in DuPage County, Illinois.

On the other hand, there are some good wetlands out there. Many are small, and this along with their isolation may limit them.

This beautiful little fen at Richard Young Forest Preserve in Kendall County is completely surrounded by woodland.

This beautiful little fen at Richard Young Forest Preserve in Kendall County is completely surrounded by woodland.

Many of the interdune swales at Miller Woods in the Indiana Dunes National Lakeshore have been taken over by the common reed. This one was an exception, but I found only black-legs there.

Many of the interdune swales at Miller Woods in the Indiana Dunes National Lakeshore have been taken over by the common reed. This one was an exception, but I found only black-legs there.

This fen-like wetland at Bluff Creek in Wisconsin’s Kettle Moraine State Forest looks very good. I will want to check it earlier in the season next year.

This fen-like wetland at Bluff Creek in Wisconsin’s Kettle Moraine State Forest looks very good. I will want to check it earlier in the season next year.

Still, I have not given up hope. I found a third good population of mole crickets this year, in a swale at Miller Woods.

Mole cricket tunnels look like miniature mole tunnels. They occur around wetland edges, and occasionally have holes to let out the males’ deep chirping calls, and to provide access for attracted females.

Mole cricket tunnels look like miniature mole tunnels. They occur around wetland edges, and occasionally have holes to let out the males’ deep chirping calls, and to provide access for attracted females.

I also found melodious ground crickets at two new sites in Berrien County, Michigan. Though I did not find dusky-faced or delicate meadow katydids at the Indiana Dunes’ Great Marsh this year, I felt curiously encouraged by this.

Both species were there last year, but with the water level higher in 2013, the vegetation was arranged differently and I did not find them in the same place.

Both species were there last year, but with the water level higher in 2013, the vegetation was arranged differently and I did not find them in the same place.

Maybe the populations of many wetland species took a hit in last year’s drought, and were thinly dispersed in the expanded wet areas of 2013. This is, after all, the first year in which I have surveyed many of these sites. If they need a couple years to recover from the drought, maybe I will find the missing species in the future. Still, how to account for the lack of nimble meadow katydids? This species I have yet to find, anywhere. In the heart of the singing insect season I took my sea kayak into an area where they historically were known.

The channels at the south end of Lake Maxinkuckee in Marshall County, Indiana, have become heavily invaded by purple loosestrife.

The channels at the south end of Lake Maxinkuckee in Marshall County, Indiana, have become heavily invaded by purple loosestrife.

Even the patches of emergent water-dwelling knotweeds, a habitat specifically mentioned in some sources as good for nimble meadow katydids, had none as far as I could tell.

Even the patches of emergent water-dwelling knotweeds, a habitat specifically mentioned in some sources as good for nimble meadow katydids, had none as far as I could tell.

So the bottom line is a disappointing season for wetland species, with a few positive points and hope in the possibility that populations are at a low point from which they will recover.

Toward Singing Insect Monitoring: Dominant Frequency

by Carl Strang

When I conduct workshops or lead field trips on singing insects, people commonly ask about monitoring protocols. We have well established monitoring programs in the Chicago area for birds, frogs, butterflies, dragonflies and damselflies, plants and probably other groups I am forgetting at the moment, so how about singing insects? My answer usually revolves around the fact that different people hear singing insects differently, and this obstacle is a challenge that has yet to be solved. An important variable here is that different people hear different ranges of sound frequencies, and commonly older folks (like me) lose the ability to hear high-pitched sounds. Recently I decided to try to get a quantitative handle on this pattern, using my experience as a gauge. I went to the Singing Insects of North America website and The Songs of Insects book by Elliott and Hershberger, and lifted out the dominant frequencies sung by the species in the Chicago region.

A male short-winged meadow katydid, one of the small meadow katydids, whose song has a dominant frequency of 13 kHz.

Most singing insects produce a range of different sound frequencies when they sing, a buzz for instance consisting of a mix of many low- to high-pitched sounds. Different sounds within the mix have different energies or volumes. The dominant frequency is the loudest one in a given species’ mix. Looking at just the dominant frequency, I see that the various local species range from 1.3 to 17 kilohertz (thousands of vibrations per second, a measure of the pitch or highness/lowness of a sound). I can hear every species with a dominant frequency below 13 kHz. In fact the only species I cannot hear at all are the small meadow katydids (the members of genus Conocephalus), which sing in the 13-17 kHz range. Children and young adults can hear these, I have found. A simple, if expensive, work-around is the SongFinder device.

The long-spurred meadow katydid is my marginal species, at 12 kHz. I can hear them from close range in the woods if there aren’t a lot of competing sounds. Interesting to me is the fact that I hear them clearly at the Brookfield Zoo, where they are fairly common. I doubt that the zoo’s long-spurreds have lower dominant frequencies. My best guess is that the relative lack of other sounds in that range, plus the amplification of the songs reflecting from sidewalks and buildings, increases my ability to hear them there.

Long-spurred meadow katydid, my marginal species

Another related variable is a person’s ability to pick up a sound from a distance. Roesel’s katydid has a dominant frequency of 15 kHz. I can still hear them, but less well with each passing year, and I have to be closer to them. Children and young adults easily pick them up earlier in the song and at a much greater distance. Probably what I hear is not that dominant frequency but the lower part of the frequency range included in Roesel’s buzz. Recently I learned that young adults can hear common meadow katydids, dominant frequency 10 kHz, at a much greater distance than I can, though I hear them clearly if I am within, say, 30 feet.

Common meadow katydid

I think that monitoring protocols are possible to develop, but clearly these are variables that will need to be taken into account. There are other obstacles as well, which I will address at another time.

Meadow Katydid Nymphs

by Carl Strang

One project in my study of singing insects is to learn to identify nymphs, the immature stages, of katydids. This could extend the survey season, as I could begin a month or two earlier than at present. At some point, rearing and taking quantitative measurements will be necessary (unless there is some reference I have not found), but for now I am taking a lot of photos and looking for possible characteristics to watch. I am beginning at Mayslake Forest Preserve, which has relatively few species. Recently the first slender meadow katydids matured and began to sing.

Mature male slender meadow katydid. Note the long wings, green cerci at the abdomen tip, and the green femurs with lines of tiny, separated black dots.

Some of the nymphs I was catching in the sweep net looked like they, too, might be males of this species.

This nymph likewise has green cerci, though not yet in adult form, and green femurs with tiny, separated black dots.

Some of the female nymphs show the same color pattern, though they have undeveloped ovipositors rather than undeveloped cerci.

Again, a bright green general color with tiny black dots on the femurs.

In contrast, many of the nymphs show color patterns that I suspect tie them to adult short-winged meadow katydids, the other common member of genus Conocephalus at Mayslake.

Note the browner ground color, the many brown dots, the yellow-brown cerci, and especially the femur with its central clear zone bounded on each side by a brown band.

Females are similar.

Again the green is paler, and the femur shows the same striping.

Some nymphs are more ambiguous, but most seem to fall into one or the other color pattern, which is encouraging.

Red-legged Grasshopper

by Carl Strang

Over the past couple months there have been large numbers of grasshoppers at Mayslake Forest Preserve, especially around trail and parking lot edges where mowed lawns come up against a variety of unmowed forbs and grasses. My focus in recent weeks has been on singing insects, but with that research checklist essentially complete for the year I decided to look into those grasshoppers. Perhaps I waited too long, as every hopper I got a good look at last week appeared to belong to the same species. I collected a couple of them and, after a session with references and the microscope, settled on an identification.

Red-legged grasshopper, Melanoplus femurrubrum

As I went through the references and keys I was surprised by the number of similar species and the small features that can separate them. Very close ones often segregate by habitat, however, and red-legged grasshoppers are one of the most abundant, weediest species. Ecologists think of weeds as organisms which reproduce in large numbers and occur in disturbed habitats. Therefore, animals as well as plants can be weedy.

While scrutinizing grasshoppers in the field I also got looks at several small (Conocephalus) meadow katydids. All clearly were short-wingeds, except for one.

The oddest feature on this female is the kink in her ovipositor.

She had an abdomen tip colored like that of a straight-lanced meadow katydid, but the shorter ovipositor and leg striping pattern pointed to short-winged meadow katydid, so I am staying with that more conservative identification.

Horlock Hill

by Carl Strang

Horlock Hill Prairie is regarded as one of the highest quality bits of dry prairie in northern Illinois. It is located right at the start of the Great Western Trail in Les Arends Forest Preserve in Kane County, and I have zipped right past it on my bike many a time without realizing its significance.

The designated natural area itself is small, at 2-3 acres, but I was impressed by the floral diversity.

Adjacent meadows and prairie restoration projects enlarge the effective area in prairie or prairie-like vegetation. In one of these I spotted a small meadow katydid which appeared at first to be a short-winged, but lacked the orange abdomen tip. He allowed me to get some photos, and when I looked at them later I was pleased to see the distinctive cerci of a straight-lanced meadow katydid.

The cerci are the little pincer-like structures at the tip of the abdomen. They are long, straight, abruptly flattened in the tips, and the small, inward-pointing tooth is near the base of each.

I found a female of this species at Mayslake Forest Preserve last year, but this is the first male I have seen. The only congeners I heard around Horlock Hill through the SongFinder were abundant short-winged meadow katydids. It was a cool, cloudy day, however, and the song of the straight-lanced is a steady uninterrupted faint buzz that may have been too faint to hear under those conditions. Certainly the short-wings were slowed quite a bit.

Otherwise the singing insects there were all of common species, except that I heard a couple probable broad-winged tree crickets. All of this points to a return to that site under warmer conditions.

Stripes

by Carl Strang

Identifying species of small meadow katydids (genus Conocephalus), especially nymphs, can be challenging. Most adults are readily sorted out, especially males if you can get a good look at the cerci or claspers at the tips of their abdomens.  Females are trickier, but their ovipositors often allow distinctions to be made. I’ve decided to take a shotgun approach in my survey at Mayslake Forest Preserve, sweep sampling on a weekly basis and taking photos of as many individuals as I can. Last week I noticed something that is potentially helpful.

This is an unambiguous male short-winged meadow katydid. Cerci are right, lots of orange color around the abdomen tip, short wings, small size.

As I compared my many photos, I found that the color pattern on the sides of the hind femurs drew my eye. Notice the band of clear green color bounded by brown stripes on either side. Here’s a female, again clearly a short-winged.

Though she may be an instar short of adulthood, this one has the ovipositor of a short-winged.

Again the color pattern on the femur appears. I did an Internet search, and except for some photos from Texas, short-winged meadow katydids show this striping pattern across eastern North America. Then I began to compare other species. I started with another familiar one, the slender meadow katydid.

This male I photographed last year has clear green femurs, without the stripes.

Again an Internet and reference book search showed consistently clear green femurs on this species. However, I was surprised to find that a female I had identified a couple years ago as a slender meadow katydid had the femur stripes.

The long wings fooled me. The ovipositor actually rules out slender meadow katydid. This was a rare individual short-winged meadow katydid with long wings.

Next I turned to two species I have been seeking, which could overlap with the short-winged’s habitat. Straight-lanced meadow katydids in references and Internet photos lack the short-winged’s stripe pattern, instead often showing a diffuse blackish zone down that face of the femur. I went to photos of females I tentatively had identified as that species last year.

This one not only has an ovipositor much longer than the femur length, and lacks orange at the abdomen tip, but shows a femur color pattern different from the short-wingeds’ and consistent with straight-lanced reference photos. In fact it appears that the diffuse black zone is the same as the upper dark stripe on the short-winged, but differing in color and not sharply bounded. The lower stripe is there as well, but just as a trace of a line. I believe this individual may indeed have been a straight-lanced meadow katydid.

Others prove, on closer inspection, in fact to have been short-wingeds.

This young nymph has an ovipositor marginally longer than the femur, but has an instar or two to go until maturity and looks awfully orange around the abdomen. The femur color pattern clearly ties it to short-wingeds, and I think that is where this insect belongs.

The other species I need to sort out is the prairie meadow katydid. Few photos of this one are out there. In some there is no stripe pattern like the short-winged’s, in some there is a hint of one. For now I will need to focus on cerci (straighter, more pointed and with distinctly longer teeth than the short-winged male’s) and ovipositors (proportionately more curved than the short-winged female’s). I am encouraged, however, to continue looking for details of color pattern that might provide short-cuts to field identification at least in regional or local populations.

Seeking Singers

by Carl Strang

The middle of August through September is the peak singing insect season, and on Tuesday I took the first of a scattered series of vacation days to work on a long checklist of targets. I started with searches of the McKee Marsh edge at Blackwell Forest Preserve, and the area around the bridge over the West Branch of the DuPage River at Winfield Mounds Forest Preserve. My main targets were long-tailed and black-sided meadow katydids. I first found those two species in the county last year, and went to these likely locations in hope of finding more. At Blackwell I found mainly black-legged and short-winged meadow katydids, our two most common species in their respective genera. I also saw a few conehead nymphs like this.

Only about an inch long, and lacking wings, these will have to grow fast to complete their development this season. I suspect they are round-tipped coneheads.

After considerable wading through vegetation depressingly dominated by reed canary grass, I finally spotted a female long-tailed meadow katydid. She did not provide a photo op, but I did post some photos last year from another location.

The Winfield Mounds bridge was on the list thanks to my meeting a photographer who had placed a photo of a black-sided meadow katydid on his website. He said he took the picture at the bridge. Again I found a lot of reed canary grass, but dutifully waded in. Again, plenty of black-legs and short-wingeds, but there were scattered others including a female Say’s trig who hopped onto my net.

I didn’t realize how big the females can get, and how they can have long wing extensions reminiscent of a two-spotted tree cricket’s, until I met this individual. She was a good centimeter long.

Shortly after photographing the trig I spotted a black-sided meadow katydid, and so they indeed persist in that area.

« Older entries

%d bloggers like this: