Seeking Northern Limits: Confused Ground Cricket

September 30, 2013 at 5:48 am (singing insects)
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by Carl Strang

One consequence of this year’s 22-county survey of singing insects is an improved understanding of how some species tail off in density toward the edge of their range. Earlier I highlighted this theme for the lyric cicada and jumping bush cricket. Today begins a series of 3 posts focusing on additional species, beginning with the confused ground cricket.

Confused ground cricket

Confused ground cricket

This is a woodland species, well distributed in the region but with a northern range limit within the 22-county area.

Map indicating the counties in which confused ground crickets are known to occur.

Map indicating the counties in which confused ground crickets are known to occur.

They are spottily distributed throughout the region, but usually in good numbers where they occur, especially toward the south. There are plenty in DuPage County, one of the two northernmost Illinois counties marked on the map. Kenosha County, Wisconsin, is marked because I heard a tiny group of confused ground crickets singing at the New Munster State Wildlife Area. I searched a number of other likely looking spots in that county and the other two Wisconsin counties, without finding this species. It was late enough in the season, though, that I need to make an earlier effort next year, and also to seek them in the other unmarked counties.

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Pine Tree Cricket

September 27, 2013 at 6:05 am (singing insects)
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by Carl Strang

One of the nicest aspects of scientific inquiry is the discovery of other people pursuing shared interests. My own study of singing insects in northeast Illinois, northwest Indiana and adjacent counties in Wisconsin and Indiana has placed me in contact with Gideon Ney, whose pursuit of coneheaded katydid evolution in his Ph.D. thesis work at the University of Missouri has added the marsh conehead and slightly musical conehead to the region’s species list. Dennis Nyberg and associates at the University of Illinois Chicago have led me to the short-grass prairie cicada. Botanist Scott Namestnik and I have collaborated in mapping the regional distribution of Roesel’s katydids.  Lisa Rainsong conducts a similar regional survey of species in the Cleveland area, allowing a valuable comparison of notes. And now I owe my thanks to Nancy Collins for introducing me to the pine tree cricket. Nancy is one of those rare people who develop such a strong interest in some aspect of natural history that they go on to make genuine contributions to science. She has traveled through the U.S. and into Central America searching for tree crickets, and has been involved in the discovery of new species. Her website provides an excellent overview of this charming group of insects.

Nancy came out to the Bong Recreation Area when I was surveying the southeast Wisconsin counties a couple of weeks ago, and helped me learn to recognize the song of the pine tree cricket. She also provided a male for me to photograph and record in an isolated indoor setting.

Pine tree cricket, recovering from a few minutes in the freezer to slow him down so I could photograph him.

Pine tree cricket, recovering from a few minutes in the freezer to slow him down so I could photograph him.

And the ventral view. At some point I will risk a more lifelike pose with him warmer and more active.

And the ventral view. At some point I will risk a more lifelike pose with him warmer and more active.

I had not focused on this species because the references seemed to indicate that it is only on the fringe of my area. Thanks to Nancy I now expect to find pine tree crickets throughout the survey area. Already I have found two populations in DuPage County, for instance, one of them at Mayslake where I work, and the other two miles from my home, at Fermilab. The Fermi population is particularly instructive, because the groves of conifers hosting the crickets are widely separated by expanses of prairie. This is a small insect with a narrowly defined habitat, but impressive dispersal ability. I suspect they have been able to jump around mainly by their affinity for red cedars, which readily spring up in open areas where birds disperse their seeds after eating the berry-like cones.

The song is not particularly intrusive, but easily recognized if you know what to listen for. Approach a large grove of coniferous trees in late summer or early autumn, late afternoon or early evening, and listen for a steady, high-pitched, sweet-toned trill. No other singing insect in the region has this peculiar attachment to conifers. The song of a single cricket is not particularly loud, but a chorus of them adds up significantly, and I had no trouble hearing those at Fermilab as I passed the spruces and cedars on my bicycle. Interestingly, and somewhat ironically, there were fewer in the pine groves.

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Jumping Bush Crickets Continue North

September 26, 2013 at 6:11 am (singing insects)
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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.

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Wetland Concerns

September 25, 2013 at 6:19 am (ecology, restoration, singing insects)
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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.

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Field Cricket Survey Update

September 24, 2013 at 5:51 am (singing insects)
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by Carl Strang

The familiar chirps of field crickets can be heard through the warm months, thanks to two different species with identical songs: the spring field cricket, which begins in May and continues into July, and the fall field cricket, which begins in mid-July and continues until severe frost ends its season. I have noticed that the two species do not always occur together, and in recent years have been surveying DuPage County to map the pattern.

Fall field cricket (female). The spring field cricket looks just like this; only their seasons separate them.

Fall field cricket (female). The spring field cricket looks just like this; only their seasons separate them.

Here is the recently updated map. Green circles represent places where both species occur, blue ones mark spring field cricket-only locations, and yellow indicate where I have heard fall field crickets but not the spring species.

Here is the recently updated map. Green circles represent places where both species occur, blue ones mark spring field cricket-only locations, and yellow indicate where I have heard fall field crickets but not the spring species.

Both kinds of crickets are well distributed in the county, and with only a few exceptions, fall field crickets are ubiquitous. Some of the blue circles represent fairly large areas, though, and at some point I will want to study them more closely. Before I do that, however, I will want to spot check at least some of the places where I heard only fall field crickets. My surveys have taken place in the evenings, but recently I read a study which indicated that while fall field crickets have their peak singing time in the evening, spring field crickets are more active in the morning. It may be necessary to repeat the entire spring field cricket survey. Until then, my hypothesis is that the rigors of overwintering as nymphs place a greater limit on where spring field crickets can live. Fall field crickets, more secure in their buried egg form during the cold season, have more habitat latitude.

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Encounters Along the Way

September 23, 2013 at 6:04 am (singing insects)
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by Carl Strang

As another season of field research into the region’s singing insects winds down, I am starting to look back at the highlights. Some of these were chance encounters that provided new photo opportunities. For example, there was a weakened common true katydid I found on a trail at Waterfall Glen in broad daylight. I didn’t have a good photo of the species, and posed him after removing him from the hazardous trail.

Unfortunately I neglected to place his hind legs in a natural position.

Unfortunately I neglected to place his hind legs in a natural position.

Another species for which I want a better photo is the handsome trig. Some were singing on a cloudy day down in Fulton County, Indiana, and one came out in the open, but the low light resulted in a less than sharp image.

Tiny but colorful, the handsome trig lives in the southern part of the region I am surveying.

Tiny but colorful, the handsome trig lives in the southern part of the region I am surveying.

The Indiana Dunes area provided several photographs.

This oblong-winged katydid female was emitting single clicks in response to the more complex songs of nearby males.

This oblong-winged katydid female was emitting single clicks in response to the more complex songs of nearby males.

A four-spotted tree cricket had escaped from my grasp before I could photograph it. While looking for it on the ground where it seemed to have gone, my headlamp revealed something better.

A female tinkling ground cricket, only the second member of the species I have seen (despite hearing hundreds).

A female tinkling ground cricket, only the second member of the species I have seen (despite hearing hundreds).

A similar encounter came when I was trying to get a better photo of a melodious ground cricket at Indiana Dunes State Park. Digging through the leaf litter in the area from which a male’s song seemed to be coming, I turned up a female ground cricket.

When I examined the photos, though, I saw that the palps were white. This was a female confused ground cricket, another species that was singing in the area, and the first female confused I have seen.

When I examined the photos, though, I saw that the palps were white. This was a female confused ground cricket, another species that was singing in the area, and the first female confused I have seen.

One of the last places I visited this year was the Bong Recreation Area in Kenosha County, Wisconsin. The prairie area there is extensive, and has a good population of common meadow katydids.

Despite its name, the common meadow katydid is much less frequently encountered than two of its congeners, the gladiator and black-legged meadow katydids.

Despite its name, the common meadow katydid is much less frequently encountered than two of its congeners, the gladiator and black-legged meadow katydids.

There were a few broad-winged bush katydids in the prairie, but I wasn’t successful in stalking one. This Texas bush katydid had to substitute.

There were a few broad-winged bush katydids in the prairie, but I wasn’t successful in stalking one. This Texas bush katydid had to substitute.

Such encounters, sprinkled through the field season, make for good memories.

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Sights Along the Way

September 16, 2013 at 6:15 am (botany, ecology, insects (other), reptiles and amphibians)
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by Carl Strang

It has been a memorable few weeks. This year I took the bulk of my vacation time in the heart of the singing insect season, mid-August to mid-September, and spent most of it traveling around the 22-county area, from southwest Michigan to southeast Wisconsin, where I am seeking the 100 species of cicadas, crickets, katydids and singing grasshoppers that occur (at least potentially) there. This travel took me to many memorable places.

High quality forests are scattered around the region. Sanders Park, Racine County, Wisconsin.

High quality forests are scattered around the region. Sanders Park, Racine County, Wisconsin.

I didn’t spend a lot of time in the forests, however, much as I love them. Most singing insects live in more open habitats.

The dunes around the edge of Lake Michigan provided some of the most open habitats. Warren Dunes State Park, Michigan.

The dunes around the edge of Lake Michigan provided some of the most open habitats. Warren Dunes State Park, Michigan.

One of my favorite areas was Miller Woods at the western end of the Indiana Dunes National Lakeshore.

The trail leads through savanna and past wetlands. Here it crosses a former rail foundation.

The trail leads through savanna and past wetlands. Here it crosses a former rail foundation.

The Miller Woods Trail eventually skirts a large pond at the edge of the dunes, and reaches the beach.

The Miller Woods Trail eventually skirts a large pond at the edge of the dunes, and reaches the beach.

Wetlands included Bluff Creek in the Kettle Moraine State Forest, Walworth County, Wisconsin.

The water was beautiful and clear, flowing over stones and gravel.

The water was beautiful and clear, flowing over stones and gravel.

A fen-like wetland, bordering the creek, contained species such as the fringed gentian.

A fen-like wetland, bordering the creek, contained species such as the fringed gentian.

Sure, I was paying attention to species other than singing insects. At the Houghton Lake Nature Conservancy property in Marshall County, Indiana, I encountered a couple interesting ones.

A Chinese mantis nymph stalked through the wetland vegetation.

A Chinese mantis nymph stalked through the wetland vegetation.

This gray treefrog snoozed in a leaf bed.

This gray treefrog snoozed in a leaf bed.

The most extensive prairie I encountered was in the Bong Recreation Area, Kenosha County, Wisconsin.

Its size alone speaks to the potential in this restoration project.

Its size alone speaks to the potential in this restoration project.

For now I will close with the sunset on my last evening at Bong.

The sunset was a beautiful prelude to a rainy evening in camp.

The sunset was a beautiful prelude to a rainy evening in camp.

The singing insects of course were the focus of all this travel. I’ll share images of some of them in future posts.

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Hoppers

September 9, 2013 at 5:50 am (singing insects)
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by Carl Strang

Some singing grasshopper species mature late in the season, and I have begun to encounter a few. Their identification is based on fairly clear anatomical characteristics, but good views (photos or a specimen in hand) are needed of several body parts viewed from precise angles. The songs don’t help much. Members of the band-winged grasshopper subfamily rattle their wings in flight, and members of the stridulating grasshopper subfamily rub their hind legs over the folded wings to make sounds that are essentially identical. Through trial and error I now know that I especially need: clear dorsal and lateral views of the thorax; the color and patterning of the tibias and inside surfaces of the femurs; and, usually, the color and patterning of both the front and hind wings.

The femur and tibia colors appear to be significant to the grasshoppers themselves. When a seaside grasshopper lands close to a member of the opposite gender, the two begin a stereotyped leg-lifting display.

Two seaside grasshoppers flash their colors to one another. Warren Dunes State Park, Michigan.

Two seaside grasshoppers flash their colors to one another. Warren Dunes State Park, Michigan.

The leg colors are hidden in the usual resting posture, which proves how well camouflaged these insects are. Seaside grasshopper, Indiana Dunes State Park.

The leg colors are hidden in the usual resting posture, which proves how well camouflaged these insects are. Seaside grasshopper, Indiana Dunes State Park.

The hind wing colors of the band-winged grasshoppers usually are folded out of sight. The yellow base of the seaside grasshopper’s wing looks brighter when the insect flies than it appears when fully expanded in the hand.

The hind wing colors of the band-winged grasshoppers usually are folded out of sight. The yellow base of the seaside grasshopper’s wing looks brighter when the insect flies than it appears when fully expanded in the hand.

Seaside grasshoppers are strongly associated with the Lake Michigan beaches in our region. I found more members of this subfamily in a waste area in Cook County, Illinois.

Two or three band-winged grasshopper species were here, the Carolina grasshopper and one or two with yellow wing bases.

Two or three band-winged grasshopper species were here, the Carolina grasshopper and one or two with yellow wing bases.

Some of them looked like this. Again, note the good camo.

Some of them looked like this. Again, note the good camo.

This was part of my learning process. I caught one of the grasshoppers and took some photos in the hand, but failed to get a crucial piece of information.

I was going to call this one a mottled sand grasshopper, but without a clear profile of the thorax I couldn’t be sure. Now that I have had a chance to study these photos a little more, I think this was an inland population of the seaside grasshopper.

I was going to call this one a mottled sand grasshopper, but without a clear profile of the thorax I couldn’t be sure. Now that I have had a chance to study these photos a little more, I think this was an inland population of the seaside grasshopper.

I need to go back to that site some time, not only to confirm the identity of this species, but also to check some individuals that had orange rather than yellow tibias, and may represent a different species.

Finally, there was a different-looking band-winged grasshopper at Indiana Dunes National Lakeshore.

Grasshopper colors can vary considerably with habitat, as they are strongly selected to match local background patterns. I can find no match for this color pattern in any of my references. This individual was on an old railroad bed in a savanna.

Grasshopper colors can vary considerably with habitat, as they are strongly selected to match local background patterns. I can find no match for this color pattern in any of my references. This individual was on an old railroad bed in a savanna.

I will need to go back for this one, too, but again with further study, focusing mainly on the shape and proportion of the thorax, wings and head, I am tentatively identifying it as a Boll’s grasshopper. If I’m correct, this is a dramatic example of how a species can vary from place to place. Compare the above photo to the next one.

Here is a Boll’s grasshopper at Illinois Beach State Park. This one is separated from the previous individual by only two counties’ distance.

Here is a Boll’s grasshopper at Illinois Beach State Park. This one is separated from the previous individual by only two counties’ distance.

These grasshoppers are fun. I hope to find more, as many more species in the two singing subfamilies have been found in the region historically.

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