Late Season Insects at Mayslake

September 30, 2009 at 5:45 am (dragonflies and damselflies, insects (other))
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by Carl Strang

A couple days ago I put a finish on the floral season at Mayslake Forest Preserve. Today I’ll shake a few late insect photos out of the camera. We’ll start with some Odonata.

Green darner b

At Mayslake as elsewhere, hundreds of common green darners paused in their migration to hunt above the prairies and meadows. Migrating south is thought to be worthwhile for them and other large, strong dragonflies as they can extend their breeding season and spread their genes over a larger area. The various saddlebags species also migrate. Here is a UFO shot of a Carolina saddlebags that graced the mansion lawn area one day.

Carolina saddlebags 2b

A darner that shows up in a lot of places late in the summer is the shadow darner.

Shadow darner 3b

That vertical perching posture is typical. Common milkweeds have been hosting a late-season caterpillar, the milkweed tussock caterpillar.

Milkweed tussock moth caterpillar b

They are larvae of a tiger moth. I’ll close with a predator. This Chinese mantis assumed a cheerleading pose.

Chinese mantis 1b

Then, it began to groom its hunting apparatus.

Chinese mantis 2b

Earlier I showed an egg mass, which is how the species overwinters. Soon all the insects will be going into their various dormant forms to survive the long, cold, dry months of winter.

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Long-spurred Meadow Katydid

September 29, 2009 at 5:54 am (singing insects)
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by Carl Strang

Recently I spent a day at the Brookfield Zoo, which remains to this point the only place where I have found long-spurred meadow katydids in northeast Illinois.

Long-spurred 5b

The above photo is inverted; the insect was clinging to the underside of a cedar twig. This is the first individual I found two years ago. I’d noticed its song as that of a meadow katydid, but unlike other species I’d encountered. The buzz has a loose rattling quality, and the ticks that precede the buzz sound like elements of the buzz rather than the sharper ticks produced by other meadow katydids. The overall effect is that the song sounds like an accelerating buzz. I spent some time with that first individual, and managed to get some photos of his cerci.

Long-spurred 1b

The cerci are the yellow structures at the tip of his abdomen. The long inward-projecting forks of the cerci give the species its name. References indicate that long-spurred meadow katydids like cedars, but so far I have not found them in DuPage County. On my recent zoo visit I found a couple individuals singing not from cedars but from herbaceous flowerbeds. I haven’t given up on them, and continue to seek them wherever there are cedars.

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Mayslake Autumn Flowers

September 28, 2009 at 5:56 am (botany)
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by Carl Strang

The time has come to close the book on the wildflowers of Mayslake Forest Preserve for this year. I don’t expect to find any more new ones this season. Now I have a long list of species with first flowering dates for 2009 that I can compare to those of the same species next year. Such phenological studies are good indicators of climate trends, as well as suggesting whether a given year is relatively early or late in its seasons.

The final goldenrods to begin flowering were old-field goldenrods, which I found in a small colony in the savanna.

Old-field goldenrod b

A much more abundant woodland species there is the side-flowering aster.

Side-flowering aster 1b

In the prairies and meadows, heath asters added to the grand finale of the flowering season.

Heath aster 1b

In places around the edges of the prairies a few sneezeweeds were blooming.

Sneezeweed 1b

Obedient plant, the plant that’s also a toy (if you move one of the flowers by pushing it with your finger, it stays where you moved it), pops up in the prairies here and there.

Obedient plant b

Bottle gentian, a bumblebee-pollinated species, also occurs in Mayslake’s prairies.

Bottle gentian 1b

And I’ll close by panning back to show a couple of scenes. In an earlier chapter I introduced the bur marigold. It has come to dominate a zone around the stream corridor marsh.

Bur marigold stream marsh 2b

Finally, here is part of the prairie.

Mayslake prairie flowers fall b

It’s not too late to get out and enjoy the season’s flowers, at Mayslake and other open places.

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Miscellaneous U.P. Notes

September 25, 2009 at 6:22 am (birds, botany, geology, insects (other), plant-eating insects, reptiles and amphibians)
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by Carl Strang

In this final chapter of my Michigan vacation account, I will bring together assorted observations of other animals and sights. None of this truly counts as inquiry, except that travel and the exposure it gives us to new places leads us to make comparisons with our familiar environment. Such comparisons often lead to questions and inquiries on down the line.

At Muskallonge Lake, after completing my investigation at the beach, I went for a walk along the state park’s trails.

Muskallonge Lake trail b

There were spectacular views of Lake Superior from elevated points, and flocks of migrating songbirds to investigate.

Tahquamenon Falls State Park is named for various waterfalls along the Tahquamenon River. Especially spectacular are the upper falls.

Tahquamenon Falls upper 1b

After a summer in which I made good progress in my knowledge of Illinois bumblebees, I was interested to find that in that part of the U.P., as back home, only one common species of short-tongued, generalist bumblebee is active at this point in the season. Here it’s Bombus impatiens; at the tip of the U.P. it was the beautifully marked Bombus ternarius.

Bombus ternarius 2b

B. ternarius is a northern species that does not extend its range down to Illinois.

One of the more charismatic birds that one hears and, sometimes, sees in the north woods is the pileated woodpecker. Here is a tree that has been well worked by that species.

Pileated work b

Beauty on a smaller scale, which provided a reminder of the season in transition, took the form of this aspen leaf lying on a trail.

Aspen leaf 1b

I spent most of my time at Whitefish Point. Here is a small scene I found especially compelling.

Whitefish Point 7b

As I walked out from the point to the parking lot for the final time, I found an enchanting little animal crossing the trail.

Smooth green snake 3b

Smooth green snakes occur in many places, but are so well camouflaged that we seldom have the good fortune to see them.

On my final morning at the Tahquamenon Falls campground, I found that a large number of moths had been drawn to the restroom building’s lights.

Nepytia canosaria 1b

These were nearly all males of the same species, emerging all at once.

Nepytia canosaria 3b

Nepytia canosaria, the false hemlock looper moth, is a common northern species whose larvae feed on a wide range of coniferous species including firs, hemlock, pines and spruces.

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Singing Insects at Whitefish Point

September 24, 2009 at 6:18 am (singing insects)
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by Carl Strang

The third goal of my Upper Peninsula trip last week was to study the singing insects there. Compared to northern Illinois, the singing insect fauna was very limited. At night the campground at Tahquamenon Falls State Park was quiet, except for the amazing snoring of one of my neighbors, thankfully only for one night. During the day the principal singing insect in the forest was the dog-day cicada.

Open areas such as Whitefish Point had more to offer. I was especially pleased to find that gray ground crickets are common there. Like all ground crickets these stayed well hidden. Here is typical habitat.

Gray ground cricket habitat b

This species is known from dunes areas around southern Lake Michigan, but the only time I was at Illinois Beach State Park listening for them was a windy day and I could not hear them clearly. At Whitefish Point I easily distinguished their song. Though the trills seem composed of discrete notes like those of Allard’s ground cricket, they are at least three times faster (Allard’s were there as well, making comparison easy). Also, the trills were not continuous but rather were interrupted by brief pauses that were spaced regularly in some individuals but at varying intervals in others. In addition to Allard’s, familiar crickets at Whitefish Point were fall field crickets and Carolina ground crickets.

Whitefish Point also was home to two singing grasshoppers that represented the two forms of grasshopper song production. One of them was a crepitating species like Illinois’ greenstriped grasshopper. My references point to the clearwinged grasshopper, Camnula pellucida, as the identification, though I am not certain.

Clearwinged grasshopper 2b

In the photo the male is on the left. Crepitation is sound production by the rattling or snapping of the wings in flight. In this species the rattle is much louder than that of the greenstriped grasshopper. Clearwinged grasshoppers occupied the more open dunes areas. The other form of sound production is called stridulation. A common grasshopper that stayed close to woody plants at Whitefish Point produced loud “zuzz-zuzz-zuzz” sounds with this method. My best stab at identification is Thomas’s broad-winged grasshopper, Chloealtis abdominalis.

Thomas's broad-winged grasshopper 3b

The black areas on the sides of the pronotum seem to point to that species. Another photo, taken just as the grasshopper turned to put some distance between itself and my camera, shows that from behind the legs have a lot of red on them.

Thomas's broad-winged grasshopper 5b

In stridulation, both legs are lifted and lowered at once, and rows of pegs on them rub against the folded wings to produce the sound.

I also found broad-winged bush katydids at Whitefish Point, but I will hold that discussion for a later time.

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Green Bay Lobe

September 23, 2009 at 6:26 am (geology)
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by Carl Strang

A second goal of my trip to Michigan’s Upper Peninsula last week was to investigate further the stones left by the most recent continental glacier. As I outlined in an earlier series of posts, my vacation trip last year was a pilgrimage into Canada to trace the route  of the Lake Michigan lobe of that glacier, which is responsible for the deposits which cover the land in the northeast corner of Illinois. The turquoise line in the map below follows the route I think that lobe followed.

Glacial lobe map b

I studied the various categories of bedrock northeast of Lake Superior, chunks of which were picked up by the glacier and now reside where that powerful river of ice left them when it melted away. I found that there appeared to be commonalities in the stones left as drift along the Lake Michigan lobe’s route in Canada, on the Upper Peninsula of Michigan, and in northeast Illinois. Stones northwest of that route in Canada seemed different, and I was curious to see if those differences might hold farther south along the route of the Green Bay lobe, which is the one immediately west of the Lake Michigan lobe. I chose to visit Muskallonge Lake State Park, on the U.P.’s north shore, approximately in the center of the Green Bay lobe’s route, so that I could compare the beach stones there to those at Whitefish Point, at the U.P.’s tip, which was on the route of the Lake Michigan lobe.

Muskallonge Lake sign b

It was a foggy day, but a few people were there. Some were gathering stones, a practice which might bias the results.

Muskallonge Lake beach 5b

For instance, it seemed to me that beach stones at Canada’s Agawa Bay, along the Green Bay route, included an unusual number of red granites and greenstones. If these are selectively removed by visitors, the remaining stones might not represent what had been there originally. I certainly found greenstones, and in the following photo two appear.

Muskallonge Lake beach 10b

However, there were very few compared to Agawa Bay. Here is a typical aggregation of Muskallonge stones, representing the Green Bay lobe.

Muskallonge Lake beach 1b

Here is a corresponding photo for Whitefish Point, along the Lake Michigan lobe’s route.

Whitefish Point 9b

While to my eye there did seem to be more reds and a few more greens at Muskallonge, and a few more grays and browns at Whitefish point, I don’t think the differences would hold up in a proper sampling procedure and statistical analysis. Furthermore, when I bring in a photo from Illinois Beach State Park (below), I am hard pressed to say that it is closer to one U.P. site or the other.

Illinois Beach 2b cropped

Nevertheless, the two years’ travel and study were enjoyable, and I learned a lot especially from studying the Canadian bedrock. The glacial drift may not provide additional support for the route map shown above, but the scratches on bedrock indicated by the little arrows in the geologists’ original map certainly are consistent with the turquoise line I added after last year’s trip.

Incidentally, there were places at Muskallonge Lake where there were deposits of black sands, I suspect composed of hematite like I found at Lake Maxinkuckee last winter.

Muskallonge Lake beach 4b

The next installation from this trip will be more biological.

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Whitefish Point Bird Observatory

September 22, 2009 at 6:28 am (birds, methods)
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by Carl Strang

Last week I traveled to the tip of Michigan’s Upper Peninsula. I had a few inquiry goals during the trip, which I’ll share over the next few days. The first was to spend some time with the migratory water bird counters at Whitefish Point. There are sites like this across the country, where dedicated people spend hours per day, for long stretches of days in the migration seasons, counting the birds of each species that pass by on their way south or north. Some such stations specialize in raptors, some are more general. This one focuses on water birds.

Whitefish Point 3b

I have heard that the elite birders who gather such data can be impatient with those less skilled than themselves. Such was not the case whatsoever at Whitefish Point. I felt welcomed, and my questions were answered with patience born not of tolerance but of willingness to share the observers’ own enthusiasm. The paid observer on the first, full day I spent there was Tom Prestby. Tom was skilled not only at identifying birds that to me were little more than dots even in the spotting scope, but he also clearly enjoyed sharing the experience, and his knowledge. Other, unpaid birders were there simply for the enjoyment, and some have been participating for years. I stopped by the observatory office and bought a membership. This kind of ongoing data collection is worth supporting. Check out the Whitefish Bird Observatory website. (Note that this site does more than count water birds; there are other programs, for instance a nightly owl banding project).

Whitefish Point office b

Curiously, for all the years of numbers recorded for various ducks, loons, grebes, jaegers and the like, no one knows for sure how the birds counted at Whitefish Point are getting there. They pass from west to east, along the shore, rounding the point and continuing south (Whitefish Point is near the tip of the Upper Peninsula on the Lake Superior side), but where are these birds crossing the lake from the north? No one knows: potential for more inquiry.

I spent part of a second morning at the observation site. The birds were different. For instance, where on the previous day there were lots of white-winged scoters, on this day the dominant ducks were American wigeons. Chris Neri, the lead observer on that day, taught me how at a great distance the steep forehead and relatively small bill on that duck gives the impression of beaklessness. We also were entertained by falcons. Once a peregrine streaked past at head level, just a few yards in front of us, only to land on the nearby beach where we could admire it at leisure. The resident merlin spent a long time persuading a persistent passerby that there was room for only one merlin on this point. The aerobatics of the chase elicited many exclamations of appreciation from our group.

Merlin 1b

Eventually the local bird triumphed, only to be pestered by a flock of blue jays.

Merlin 3b

More reports from this trip are forthcoming.

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Micrathena gracilis

September 21, 2009 at 5:59 am (gardening, invertebrates (other))
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by Carl Strang

A couple years ago I was pleasantly surprised to find, in the garden beds around my home, a few orb-weaving spiders of the species Micrathena gracilis.

Micrathena gracilis b

It was a happy discovery, as this is a forest spider, and it was, like the little firefly Photinus marginellus, a sign that the micro-woodland I had established around my home was successful.

I first encountered Micrathena as a child in northern Indiana. They were common in the woods there, and on our fall squirrel hunts we had to watch for them. It was distracting to get tangled in their webs, and these spiders can bite (the sensation is comparable to that of a biting fly, i.e. something one wants to avoid if possible). During my 5-year stint as an assistant professor of biology in Pennsylvania I found this spider there, as well. I noticed that the spider’s thorny-looking, black-highlighted white abdomen mimics the silk-wrapped debris from earlier feedings clustered near the center of the spider’s web.

When I moved to Illinois 28 years ago I soon noticed that only Waterfall Glen, DuPage County’s southernmost forest preserve along the Des Plaines River, seemed to have Micrathena, though they were fairly common there. Since then they have expanded north and west. A decade or more ago I first saw them at Willowbrook Forest Preserve, close to the center of the county. And now I find them each year in my yard in west central DuPage. Like the broad-winged tree cricket I featured last winter, this spider’s expanding range tells us that nature is dynamic, always changing, worth monitoring.

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Gadget 1

September 13, 2009 at 10:04 pm (methods, singing insects)
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by Carl Strang

For the most part in this blog I am trying to model methods of inquiry that don’t rely on technology. Our human senses have their limitations, but we can gather enough information through them to answer a lot of questions about our surrounding wild world. Nevertheless, there are occasions when gadgets can help. Today I will feature one of those I have found useful in my field studies of singing insects: my soprano recorder.

Recorder b

I don’t have perfect pitch, but I have a reasonably good ear. I have found the recorder to be especially helpful as I tackle the problem of the arboreal tree crickets (outlined in my earlier post on one of them, the two-spotted tree cricket ). This season one of my goals has been to sort out the songs of the two-spotted, narrow-winged and Davis’s tree crickets. I was encouraged when I noticed that Elliott and Hershberger, in their recent book on singing insects, indicated that these three species should have distinct pitches in their songs. Highest should be the two-spotted, at 3.5 kHz (kilohertz, a quantitative sound frequency measurement), which translates to a pitch of A, the fourth A above middle C. In the middle should be the narrow-winged tree cricket, at 3 kHz or approximately F-sharp, the fourth F-sharp above middle C, 3 half-tones below the two-spotted. I noticed, incidentally, that the distinctive song* of the snowy tree cricket also is indicated to be at 3 kHz, and so I had hopes that this would provide a rough and ready field standard. The lowest of the arboreal tree crickets, according to Elliott and Hershberger, is the Davis’s tree cricket, at 2.5 kHz. This translates musically to the fourth E above middle C, distinctly lower than any of the others. So, recorder in hand, I set forth.

Snowy tree cricket 5b

Snowy Tree Cricket

Two caveats quickly became clear. First, the pitch of a given species is subject to change with environmental temperature, rising and falling as the temperature rises and falls. Second, I have to keep in mind that my own hearing may not well match the measuring devices used to provide the information in that book. In general all species sounded, to my ear, a good 3 tones lower than Elliott and Hershberger suggested.

I have found that to my ear, both two-spotted and narrow-winged tree crickets have songs distinctly higher pitched than that of the snowy tree cricket. At a given temperature, the two-spotted sings one-half to a full tone higher than does the narrow-winged. However, at a given general temperature, narrow-wings range over half a tone of pitch or more. Whether this is because the microclimate is different where individual crickets are singing, or whether this is something they are controlling, I cannot say. It means, though, that I have to rely as much or more on the temporal pattern of the song to distinguish these two species.

Narrow-winged Tree Cricket

Narrow-winged Tree Cricket

Narrow-wings sing with a steady pattern of trills and spaces, with trills of equal lengths and spaces of equal lengths, and the spaces are significant at a second or so duration. Two-spotteds sing at a little higher pitch on average, have trills of varying lengths including some often lasting well over 5 seconds, usually with at least some pauses that are very brief, as though catching a quick breath.

I recently heard, on my neighborhood block count, what I believe must have been a Davis’s tree cricket. The insect was high up in a tree. Its trills were variable but generally very long, with only occasional odd interruptions. Spaces were short. Significantly, the pitch was down at A-flat, low for the temperature, which was 70F. Based on my recorder tests, at that temperature I would expect snowy tree crickets to be singing at B or C, two-spotteds at the E above that, and narrow-wings at C to E. So, the recorder is a helpful tool, but in distinguishing the songs of these crickets I find that the pattern of their song is more reliable than the pitch.

*You know the song of the snowy tree cricket, even if you live outside its range. In the movies, whenever the director wants to convey a calm nighttime mood, there will be a snowy tree cricket in the sound track. The song is a pulsing tone, varying with the temperature so that if you count the notes in 15 seconds and add 40, you have the temperature in degrees Fahrenheit. Though the narrow-winged tree cricket’s song likewise is a regular pulse, the tones are on the order of 2 seconds’ duration with a 1-2-second space between. Unless the temperature is very cool, the snowy’s song is much faster.

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Mayslake Lepidoptera Update

September 11, 2009 at 6:31 am (insects (other))
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by Carl Strang

As we move into autumn, the lateness of the season calls for us to enjoy the more ephemeral beauties of nature while we still have them. Monarch butterflies have completed their local mating and egg-laying, and have begun the migration south toward Mexico.

Monarchs mating b

Earlier in the season at Mayslake Forest Preserve I found this larva of the moth Cycnia tenera on its usual food plant, dogbane.

Cycnia tenera b

Tiger swallowtails are one of our more spectacular butterflies.

Tiger swallowtail 1b

They will overwinter in the pupal form. Late season species include the summer azure.

Summer azure b

Larvae of this little butterfly feed on flowers in the composite (sunflower) family; I have seen them laying eggs on wingstem at Fullersburg . Another common late summer species is Peck’s skipper.

Peck's skipper b

There probably will be little more to report on this group at Mayslake until next year.

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