November 21, 2014 at 7:09 am (insects (other), plant-eating insects)
Tags: Cucujus clavipes, Fullersburg, Lemont quarries, Melanoplus walshii, red flat bark beetle, Walsh's grasshopper
by Carl Strang
The arrival of snow flurries and skim ice on the lakes and marshes means that insects are pretty much done for the year. Today I will share some photos of a couple late season observations. One of these was at Fullersburg Woods Forest Preserve.
This is the red flat bark beetle, with the musical scientific name Cucujus clavipes.
I recognized that little critter thanks to the Observe Your Preserve website, through a contributed photo by Linda Padera.
Some of us in the Education department participated in a morning bioblitz at the Lemont Quarries at the beginning of November. It was a chilly morning, but we found a few insects, including a new species for me, Walsh’s grasshopper.
Not a singing species, this short-winged hopper is in the spur-throated group.
The hind tibia are orange or red with yellow bases.
This grasshopper turned up in its typical habitat, a mix of forbs and brush at the edge of a woodland.
November 19, 2014 at 7:08 am (botany, restoration)
Tags: Alliaria petiolata, experiment, garlic mustard, Mayslake
by Carl Strang
As I begin the slide toward my retirement next August, I have begun to tie up some loose ends. One of these was the need to pull markers I had left at all the garlic mustard study plots I had established over the years at Mayslake Forest Preserve. That research was very satisfying, confirming experimentally that stands of garlic mustard can be removed effectively without use of chemicals or tedious hand pulling of individual plants (the results were last summarized here in 2013).
Some of those plots go back 5 years, and I was surprised at how little garlic mustard had returned to them.
Here is one of the plots. Most of the green is from things other than garlic mustard.
A close-up from another plot. Only a few widely scattered first-year garlic mustard plants were present in each plot.
These plots were shaded, which would inhibit growth, and the limited number of plants suggests that these were new infestations which had not established much of a seed bank.
November 17, 2014 at 7:29 am (mammals)
Tags: Mayslake, mink
by Carl Strang
I can’t pretend to know much about mink. Typically I’ll get 4-6 brief glimpses of our most common weasel in the course of a year, and I’ve accumulated a total of 6 or 7 hours of “dirt time” (mainly “snow time” in this case) tracking them. With that as background, I can’t truly say how odd this little story from last Friday is. It was a cold, overcast day, and I was returning to Mayslake Hall from a relatively uneventful lunchtime walk. As I approached the little stream that serves as the outlet for Mayslake Forest Preserve’s lakes, I caught the motion of a roughly squirrel-sized mammal. It had climbed onto the base of a severely tilted willow.
The tree in question.
The animal was very dark.
Definitely not a squirrel.
As it climbed all the way to the topmost branches, 15 or so feet above the ground, I was thinking: could this be a mink? But it’s climbing a tree!
When it stopped and gave me a look, the identification was confirmed: a mink indeed. Here, the tail and hindquarters are visible to the left, the head to the right.
Fortunately for me, the critter held still and let me get enough photos that I ended up with a few that were reasonably in focus.
I had set the camera’s ISO to 2000 on that dull day. Note the white chin.
Eventually the mink climbed back down and sprinted through the woods to the safety of Mays’ Lake. Tree climbing is not typical behavior for this amphibious mammal, I am sure, but I certainly have a broader sense of the little carnivore’s capabilities after this episode.
November 13, 2014 at 6:44 am (birds, botany, dragonflies and damselflies)
Tags: American goldfinch, Amur honeysuckle, autumn meadowhawk, Lonicera maackii, mallard, Mayslake, Solidago rigida, stiff goldenrod, Sympetrum vicinum
by Carl Strang
The first half of November brought reminders that life continues through autumn at Mayslake Forest Preserve. The preserve’s prairies draw flocks of goldfinches.
This messy eater enjoys some stiff goldenrod seeds.
Though most plants were shutting down in keeping with the season, there were some anomalous exceptions.
This Amur honeysuckle opened a few flowers on November 4. May and June are the usual blooming months for that species.
Late-season insects were holding on.
The autumn meadowhawk is well named, but few are able to remain active into November.
At the same time, some species already are preparing for next year.
Mallard courtship is well under way, and tentative pair bonds already have formed.
November 11, 2014 at 6:20 am (singing insects)
Tags: fall field cricket, Fermilab, Gryllus pennsylvanicus, Gryllus veletis, spring field cricket
by Carl Strang
This is the time of year when the singing insect season is nearly done, with only the last song dates to note for the few rugged species still singing. I have been writing my annual research summary, and one data set recently completed was my Fermilab field cricket count. In the warm months I take bike rides through Fermilab, a U.S. Department of Energy research site, on roughly a weekly basis. I count the number of singing crickets I hear. The resulting graph has a double wave shape.
Counts of singing field crickets heard during bicycle rides following a standard route through Fermilab.
Two species are represented here, the spring field cricket and the fall field cricket. Their songs are identical to the ear. The graph shows that spring field cricket counts increased rapidly from the first appearance on May 18 to a peak in mid-June, then rapidly fell. There never was a time when fewer than 50 crickets were counted in July, probably indicating overlap between the two species, with the last spring field crickets continuing into the last half of that month. Fall field cricket numbers built rapidly to a peak in the first half of September, and exceeded the maximum count for spring field crickets in the same area, before dropping rapidly in early October.
October 20, 2014 at 6:00 am (singing insects)
Tags: fork-tailed bush katydid, Scudderia furcata
by Carl Strang
A field excursion for singing insects took me back to Indiana on Friday. The sky was clear in the morning, with the temperature in the upper 50’s F, but conditions deteriorated back to October wind and clouds through the afternoon. As I drove back home I had the feeling that, except for noting last song dates for species I encounter while engaged in other activities, the 2014 field season is done. Nevertheless, I had picked up another 6 county records, bringing the year’s total to 101.
This female fork-tailed bush katydid was my first of that species for Pulaski County.
The kinked shape of the ovipositor’s dorsal edge, along with the insect’s small size, assured the identification. Note the teeth around the tip, used when cutting into plant tissue for egg laying.
October 17, 2014 at 5:58 am (singing insects)
Tags: jumping bush cricket, Orocharis saltator, range extension
by Carl Strang
The jumping bush cricket is the singing insect species that is shifting its range boundary most rapidly to the north in the Chicago region.
Jumping bush cricket
This one is worth following annually, and a couple weeks ago I made a few evening drives to find how far they have advanced this year.
Here is the resulting map, on the scale of the 22-county area I am surveying for singing insects. Black dots represent counties in which I have found the species as of last year. Red stars mark the northern extent in 2013, yellow ones 2014.
The four yellow stars are in four stream corridors that the crickets sometimes follow. I did not do this check along the West Branch of the DuPage River last year. As you can see, there was a measurable hop north. For the first time I found them in Kane County; they were just south of there in Kendall last year. Also, now they have extended into northern Cook County both along Salt Creek and the Des Plaines River. These new locations represent about a half-mile northward shift, and I will be interested in finding whether they maintain that rate next year.
October 15, 2014 at 6:16 am (singing insects)
Tags: Davis's tree cricket, narrow-winged tree cricket, Oecanthus exclamationis, Oecanthus niveus
by Carl Strang
A recent moment of excitement proved to be unfounded. I was hosing off the driveway, preparatory to sealing it, when the spray flushed out a tree cricket hidden in the siding.
The color spot seemed confined to the head. Could this be a Davis’s tree cricket?
I never had seen a Davis’s, though I have heard them singing several times. They generally stay high up in trees, and their songs are so buried in the nighttime wall of sound produced by other singing insects that I don’t have a good sense of their abundance or distribution. I spent a good half hour photographing this female before it occurred to me to check the basal antenna spots.
The curved, hook-like shape of the spot on the basal segment told me this was not a Davis’s, whose spot simply would be straight, but rather a narrow-winged tree cricket, a very common species.
Nevertheless, there are lessons to be learned in every experience, and now I have a usable photo of the narrow-wing’s spots.
October 13, 2014 at 6:03 am (insects (other), mammals, plant-eating insects, reptiles and amphibians, singing insects)
Tags: black-legged meadow katydid, Chortophaga viridifasciata, greenstriped grasshopper, Henry's marsh moth, Mallota bautias, Mayslake, mink, Orchelimum nigripes, plains garter snake, scissor-grinder cicada, Simyra henrici, Tibicen pruinosa
by Carl Strang
Now that we are getting autumnal weather, it’s a good moment to look back at the summer just past, and at the current hints of what is coming. Here are photos from the past month at Mayslake Forest Preserve.
This dorsal view of a black-legged meadow katydid doesn’t show off his colors, but as he pauses between songs we can see the sound-production structures in the bases of his wings.
Usually I’m good at spotting bee mimics, but this large syrphid fly had me calling it a common eastern bumblebee for several seconds before I realized my error.
According to BugGuide, “larvae are deposit filter-feeders in water-filled tree holes,” which explains why Mallota bautias don’t turn up very often.
When I spotted the scissor-grinder cicada on the horizontal branch I took advantage of the opportunity for an unobstructed telephoto. Only when I was cropping the picture in the computer did I notice the second individual on the vertical branch.
So much for summer. Now for hints of the season to come.
This brown, probably male, nymph is a greenstriped grasshopper, the species that will kick off the singing insect season next spring. They get started early because they overwinter in this form rather than in eggs as do most of the species singing now.
This Henry’s marsh moth caterpillar was clambering over the tangled stems of a reed canary grass patch, probably seeking a pupation spot for its winter hibernation.
These mink scats, freshly deposited on a path near the stream, are the first sign of that species I have seen in a while. Perhaps this mink will center its winter activities around Mayslake’s wetlands.
Reptiles and amphibians are moving toward their hibernacula. Recently I spotted a garter snake that looked different from the usual Chicago version of the eastern garter snake.
It was paler around the head and neck.
The side stripe is on scale rows 3 and 4, and other details support the identification of plains garter snake, a new species for the Mayslake list.
October 10, 2014 at 6:04 am (plant-eating insects)
Tags: Melanoplus femurrubrum, red-legged grasshopper
by Carl Strang
This is the first year in which I have searched for singing grasshopper species with the same intensity as for cicadas, crickets and katydids. Since the grasshoppers seldom sing, and when they do have essentially identical songs, I have had to learn about the structure of grasshoppers so as to identify them. The most common species in the region seems to be a non-singing one, the red-legged grasshopper. It therefore is an important one to learn about.
Red-legged grasshoppers belong to the spur-throated grasshopper group. Here is a close relative, the pine tree spur-throated grasshopper. The rounded peg between the front legs is the uniting feature of the group. None of the singing grasshoppers possess it.
Here is a red-legged grasshopper female. Female grasshoppers have pointed abdomen tips, formed from the valves of the ovipositor.
Female structures are similar enough that species identification is more difficult. It is best to focus on males.
Note the rounded abdomen tip in the male red-legged grasshopper. The dark, relatively unbanded but somewhat herringbone pattern of the femurs, along with the red tibias and the wing length, are helpful in identifying this species in either gender.
In the male red-legged, the abdomen tip is swollen. The cerci (the pale pair of small structures a bit back from the tip and on top of the abdomen) are shaped like elongated triangles with rounded points.
Viewed from the end, the rounded edges and the U-shaped central depression in the subgenital plate (the structure occupying most of what you see from the end) are diagnostic for the male red-legged grasshopper).