March 9, 2011 at 6:47 am (methods, singing insects)
Tags: Conocephalus brevipennis, short-winged meadow katydid, singing insects monitoring, Songfinder
by Carl Strang
One of the great benefits of teaching is that the instructor learns as much or more than the students. Yesterday I mentioned my “Wild Things” presentation on Saturday in which I shared some information on singing insects with 80 or so members of my audience. Among them were two little girls, and they, along with the questions and comments I received during my presentation, led to a brainstorm afterwards that I still am working out, but would like to share here.
One of the challenges of working with singing insects is that no one has fully worked out yet how to conduct an organized monitoring program that covers all species. The biggest single difficulty is that different people hear the insects differently. Age is a major factor. Many singing insects have very high-pitched songs, and as we age we lose the capacity to hear those high frequencies. When I have taken people into the field to listen to singing insects, we often are hearing different things, and I haven’t figured out how to get around this problem.
The short-winged meadow katydid probably is our most abundant katydid. Their songs are loud, but I cannot hear them because I have lost the ability to hear the high-pitched sound frequencies they produce.
The model that has been developed for monitoring is that individuals are trained to recognize the members of a species group, whether it be dragonflies, butterflies, frogs (by song) or breeding birds (mainly by song). The monitors then go out to an assigned area and record the species they observe.
Perhaps the way to deal with the special challenge of singing insects is to have monitoring done not by individuals but by teams, and each team must include at least one interested child.
Of course, a younger adult still able to hear all the singing insects, unaided or with a device such as the SongFinder, could do solo monitoring.
I especially like the idea that the child would be an essential and necessary team member, doing something that big grownups cannot do, making an important contribution. The adults, less distracted by the songs they cannot hear, could focus on the singers in their hearing range. That is as far as I have taken the idea so far, but I am hoping to develop it enough to explore further.
October 14, 2010 at 6:13 am (singing insects)
Tags: Conocephalus brevipennis, Conocephalus nemoralis, fall field cricket, Gryllus pennsylvanicus, Gryllus veletis, short-winged meadow katydid, spring field cricket, Waterfall Glen, West Branch, Winfield Mounds, woodland meadow katydid
by Carl Strang
This past weekend I took advantage of the warm weather to see about filling some absences in my singing insects records. First, I wanted to get some clarity on the apparent absence of fall field crickets (FFC) from Winfield Mounds and East Branch Forest Preserves. Second, I hoped to find woodland meadow katydids. Winfield Mounds is a fairly large preserve, and it contains a considerable area of habitat that appears to be suitable for FFC.
I extended my search through several habitats like this, and despite repeated visits to this preserve have failed to find FFC there. Winfield Mounds does, however, have the spring field cricket, sibling species to the FFC. The closest FFC I found to the preserve were several singing in a railroad embankment just across the road from the preserve’s southern edge.
I frequently put on the SongFinder to see if I could locate woodland meadow katydids in or near the woods edges. There were none. Mostly I was hearing short-winged meadow katydids. As I was checking the reconstructed mounds for which the preserve was named, I found this singer.
Its song was that of a short-winged, and the grassy bit of habitat was appropriate despite being in the center of the woods.
However, this insect had very long wings. Its song, coloration, and cerci (below) showed it to be a rare short-winged meadow katydid with long wings.
I went on to the area surrounding East Branch Forest Preserve. The closest FFC I found was in a residential neighborhood, several blocks away from the preserve boundary. There is a lacuna in the species’ local distribution, but it is not huge. East Branch, like Winfield Mounds, has spring field crickets.
Waterfall Glen would seem the most likely place to find woodland meadow katydids in DuPage County. Earlier I had searched without success in the western part of that large preserve. This weekend I made two stops in the eastern part. Again, I was hearing plenty of short-winged meadow katydids. Here is one of them, with a more conventional wing length.
I have come to the conclusion that this is the most abundant meadow katydid by far in DuPage, and among singing insects is rivaled only by the three common ground cricket species. I failed again to find woodland meadow katydids, and I wonder if they are supplanted locally by short-wingeds.
September 17, 2010 at 6:22 am (botany, dragonflies and damselflies, restoration, singing insects)
Tags: black-legged meadow katydid, black-sided meadow katydid, Conocephalus attenuatus, Conocephalus brevipennis, Conocephalus nigropleurum, Conocephalus strictus, dolomite prairie, Hines emerald, long-tailed meadow katydid, Orchelimum nigripes, Phalaris arundinacea, reed canary grass, short-winged meadow katydid, Somatochlora hineana, straight-lanced meadow katydid, Waterfall Glen
by Carl Strang
I needed to return to the dolomite prairie at Waterfall Glen as part of my targeted singing insects search. This had been my dragonfly monitoring area until I switched to surveying the nearby Des Plaines River by kayak, and I hadn’t been in the dolomite prairie for two seasons.
This is a unique environment, arguably the rarest in the county, as it is a prairie growing in a thin soil layer that has developed atop a shelf of Silurian dolomite bedrock in the few thousands of years since the last continental glacier melted away. In my dragonfly monitoring there I had seen federally endangered Hines emeralds hunting a few times. This prairie is not established as a Hines breeding area, though they are known to reproduce nearby. As I walked through the drier part of the prairie depicted above, I noticed some meadow katydids, including this female straight-lanced.
My particular interest, though, was a small area of tall sedges and grasses in the wetter east end of the prairie.
This is where I took the photograph of the female katydid nymph I shared a couple posts ago, the brown one that might have been a black-sided, might have been a long-tailed. Almost immediately as I entered the area I began to see a few black-sided meadow katydids, including this female.
But that wasn’t all. In addition to one of the highest densities of black-legged meadow katydids I’ve ever encountered, I also began to see all-brown individuals including this female.
This was almost certainly a long-tailed meadow katydid. According to one paper I’d read, as of 1983 at least there were no known places where black-sided and long-tailed meadow katydids occurred together. I don’t know whether that has changed in the quarter-century since that publication appeared, but if not then this could well be the first documentation of such a co-occurrence. Considering the potential significance of this find, I went ahead and collected one of the all-brown males, while taking close looks at others like this one.
It proved indeed to be a long-tailed meadow katydid. As I sampled the area with my sweep net I also turned up some colorful individuals like this one.
It has a brown body, and in fact except for the green legs is much like the all brown long-taileds. I was tempted to regard these as variants of the short-winged meadow katydid, a much more common species, because some of them had very bright yellow abdomen tips.
In the end, though, I had to conclude that this was a population of long-tailed meadow katydids with both brown-legged and green-legged individuals. Photos supported the structure of the green-legs’ cerci being closer to long-taileds’ than to short-wingeds’, and while in the literature I could find some references to long-taileds with green legs I could find no mention of short-wingeds with brown bodies.
Thus this small area at the east end of the dolomite prairie, which also is the only part of the whole site where I have seen Hines emeralds hunting, proves to have considerable scientific value. Unfortunately it may be on the verge of being lost. It is smaller than it was even two summers ago, as reed canary grass is invading and displacing the tall sedges and native grasses. I don’t know if anything can be done about this. Herbiciding the reed canary grass probably would also do in the native species, and as I understand it there are no other options. I have to hope the Hines’ can hunt elsewhere, and that these meadow katydid populations will be able to hang on in the marginal habitat with which they will be left if the trend continues.
September 14, 2010 at 6:05 am (singing insects)
Tags: black-legged meadow katydid, black-sided meadow katydid, Brewster Creek, broad-winged bush katydid, Conocephalus brevipennis, Conocephalus nigropleurum, Orchelimum nigripes, Pratts Wayne Woods, Scudderia pistillata, Scudderia texensis, short-winged meadow katydid, Texas bush katydid
by Carl Strang
Pratts Wayne Woods is the largest of DuPage County’s forest preserves. While its 3500 acres have much to offer, the target of my most recent visit was the Brewster Creek Marsh. I had a couple species of meadow katydids in mind that I especially hoped to find there. The part of that marsh I was surveying was adjacent to a dry area where there are high-level equestrian jumping competitions. As I passed through part of that meadow I heard a bush cricket’s short song. It took some minutes to find him, as he took advantage of the light wind moving his perch to keep an edge toward me.
His song was a little ambiguous. I have come to think of the broad-winged bush katydid’s short song as sounding blurred, run together, and composed of more than 3 syllables. The Texas bush katydid usually has a three-syllable short song that sounds, to my ear, crisp and articulated: dig-a-dig! I needed to take the time to find this individual because his short song had 3 syllables but sounded slurred together.
The wing proportions alone say Texas bush katydid, but to be sure I caught him and photographed his tail plate, confirming the ID. Now it seems I will have to find a few more and confirm that it’s the syllable count rather than the crispness that matters in separating these two species. Soon thereafter I found myself in a wet area dense with tall sedges in northern Brewster Creek Marsh.
It was disappointing, however. There was essentially nothing to be found out in the sedge area, and just a few black-legged and short-winged meadow katydids singing along the edge. I moved west to a grassy area at the edge of a large pond. As I stepped out of the woods into that grass I caught a flash of golden brown as a slender jumper got out of my way. My immediate hope was fulfilled when a close look proved the insect to be one of my target species, a male black-sided meadow katydid.
This was the best photo I got of a male. The abdomen is mainly a shiny black in color. I saw several males, and also a female.
She easily is the most colorful small meadow katydid I have seen, and would vie with the male black-leg (a large meadow katydid) as the local show winners for subfamily Conocephalinae.
September 13, 2010 at 6:03 am (singing insects)
Tags: Anaxipha exigua, black-legged meadow katydid, Blackwell, Carolina ground cricket, Conocephalus brevipennis, Conocephalus fasciatus, Eunemobius carolinus, long-spurred meadow katydid, narrow-winged tree cricket, Oecanthus niveus, Orchelimum nigripes, Orchelimum sylvaticum, Say's trig, short-winged meadow katydid, slender meadow katydid, Songfinder
by Carl Strang
My second stop in my targeted search for singing insects was Blackwell Forest Preserve, specifically the Mack Road Marsh in south Blackwell. This is where the Blackwell Canada goose roost is located in winter, though no geese were there on the afternoon of this visit. As I followed the trail that skirts the edge of the marsh I heard plenty of common species (black-legged meadow katydids, Say’s trigs, Carolina ground crickets, and a narrow-winged tree cricket), and also saw some short-winged and slender meadow katydids. There were enough small willows and other coarse plants that I had few places to swing a sweep net. One sample at the edge of the water caught a couple black-leg males and this female Orchelimum (large meadow katydid genus).
She appears to be one instar short of adulthood. Her ovipositor shape to my eye could place her in one of several species, and she has the simple green and black color pattern typical of nymphs in both of our genera of meadow katydids. The photo is worth keeping for future reference, but otherwise she is unidentified, for now. As I headed back out that trail I put on the SongFinder. When black-legs are around, their songs can overwhelm the hearing, and the SongFinder’s filters don’t take them out. At one point I heard a new song pattern, however, coming from an area where grasses and some mountain mint were growing amid willow wands and some sawtooth sunflowers.
After some searching I found one of the singers, but could not get a good photo of his cerci.
As he was almost certainly a new species for my county list, I collected him. To my surprise he proved to be a long-spurred meadow katydid. Previously I had found these singing at Brookfield Zoo in Cook County, and on this most recent Labor Day weekend I was sure I had heard a couple in a woods near Culver, Indiana, that I passed on a bike ride. Those experiences led me to think this species’ songs always were audible to me. Here at Blackwell, however, though I could hear them faintly without the SongFinder I never would have noticed them without it.
This raises two possibilities, one disturbing and one intriguing. The disturbing possibility is that my Culver identification was mistaken, and my hearing has declined significantly in the past twelve months. The intriguing possibility is that these katydids alter the frequency range of their songs in different locations. At Brookfield Zoo and in those woods near Culver, there were few other singers. At Blackwell there was an abundant congener, the black-legged meadow katydid, singing in numbers. Though the songs of the two species are distinct enough that I can easily distinguish them, perhaps in these circumstances shifting to a different band width makes the male long-spurs easier for the females to find.
August 31, 2010 at 6:14 am (singing insects)
Tags: black-horned tree cricket, Conocephalus brevipennis, Conocephalus fasciatus, Conocephalus strictus, Forbes's tree cricket, Mayslake, Oecanthus forbesi, Oecanthus nigricornis, short-winged meadow katydid, slender meadow katydid, straight-lanced meadow katydid, sweep net
by Carl Strang
I have continued to search for small meadow katydids at Mayslake Forest Preserve, and in my most recent effort I hit the jackpot. I visited some low, sedge-dominated wet areas (though with dry soil at this time of the year) at the east edge of the preserve.
In all other habitats I found around one katydid in every 2-3 sweep-net samples. Here each 25-sweep sample had several. In four samples I caught a total of 18 meadow katydids. By far the majority (13) were slender meadow katydids. There also were short-winged meadow katydids, among them this male.
At first I thought this nymph might be a straight-lanced meadow katydid, but a close look at the claspers at the end of his abdomen said otherwise.
The blunt, blade-like, slightly bent shape is that of a short-winged. I did find a couple female straight-lanced, including this one with an impressively long ovipositor.
I also picked up a couple tree crickets, both of which I think are, yet again, black-horned or Forbes’s. One was a relatively pale nymph.
The other was a more typical adult.
This experience, along with suggestions from the literature, point me toward wet, sedge dominated areas for further explorations.
August 25, 2010 at 6:40 am (plant-eating insects, singing insects)
Tags: Antheraea polyphemus, Conocephalus brevipennis, Conocephalus fasciatus, Conocephalus strictus, Mayslake, polyphemus moth, short-winged meadow katydid, slender meadow katydid, straight-lanced meadow katydid
by Carl Strang
Yesterday I described sweep sampling. The day after I tried out the technique in the stream corridor prairie, I shifted to Mayslake’s savannas. The first sample, taken in the tall herbaceous vegetation at the edge of the north savanna, produced this female meadow katydid.
The critical feature, as I understand it, is the length of the ovipositor, the sword-like extension at the tip of the abdomen. On this individual the ovipositor is longer than the femur, and so I conclude that it is a straight-lanced meadow katydid. This was the first species on the list of those I had not yet found, as it is said to be very common. The song is a faint, high-pitched, continuous trill, which fates it to blend with all the other insect songs even with the aid of the SongFinder. The short-winged and slender meadow katydid songs are easier to pick out because the trills are relatively short and preceded by ticks. The spaces, starts and stops allow those songs to stand out. Other features that may distinguish it from those other two small meadow katydids are the short wings (compared to the slender meadow katydid’s very long ones) and the green abdomen tip (that of the short-winged meadow katydid is yellow).
Among the other insects that turned up in the savanna sweep samples was this little caterpillar, which may be an early instar of the polyphemus moth.
I will continue to seek out the more obscure singing insects.
August 24, 2010 at 6:10 am (dragonflies and damselflies, insects (other), methods, singing insects)
Tags: black-horned tree cricket, citrine forktail, Conocephalus brevipennis, Forbes's tree cricket, Ischnura hastata, Limenitis archippus, Limenitis arthemis, Mayslake, mimicry, Oecanthus forbesi, Oecanthus nigricornis, red-spotted purple, short-winged meadow katydid, sweep net, viceroy
by Carl Strang
There are two groups of singing insect species about which my knowledge is most lacking. First there are the ground crickets, which are audible but have songs that often are similar, and they are difficult to catch for the purpose of identification. And then there are the small meadow katydids, whose songs are so high pitched that I can no longer hear them, or are so soft that they are overpowered by the many other louder species around them. Thanks to the SongFinder I have found two of these, the short-winged meadow katydid and the slender meadow katydid. Last week I employed another technique in this search: the sweep net.
A sweep net is like a butterfly net, but the bag is made of a heavy close-woven fabric that withstands being swept back and forth through vegetation. I started my search in the stream corridor prairie at Mayslake Forest Preserve. I tried taking 25-sweep samples in various parts of that prairie. The first interesting insect I caught was this one.
I released this bird-dropping-mimic butterfly caterpillar after photographing it. I thought it looked familiar, but never had seen one live. Later I found that it was a viceroy butterfly larva, which is almost identical to that of the red-spotted purple. The two species are very closely related, being in the same genus, but selection has pushed adult color development in two entirely different directions. The sweep sampling session added one new species to the preserve list.
This is a citrine forktail. Several fell into the net, but they are so well camouflaged and so still on their perches that I had not noticed any before. The singing insects I caught belonged to familiar species. Here is a female short-winged meadow katydid.
I also caught a tree cricket. This was a more typical example of the black-horned/Forbes’s species pair than the individual I described in a post a few days ago.
Though pale on the back, it was dark beneath the abdomen, and the antennal spotting was unambiguous.
Those spots are large, dark, and smudged together.
October 16, 2009 at 6:47 am (methods, singing insects)
Tags: Conocephalus brevipennis, Conocephalus fasciatus, Mayslake, short-winged meadow katydid, slender meadow katydid, Songfinder
by Carl Strang
In an earlier post I wrote about how the soprano recorder, a musical instrument, has been helpful in my singing insects research. This summer I acquired another gadget and began exploring its potential.
This is the SongFinder. Microphones on each earpiece take in sounds, the electronic box alters them by reducing their pitch, and sends the results back to the earpieces. You can slow sound frequencies by one-half, one-third or one-fourth. You also can set threshold sound frequencies below which the device does no alteration. At several hundred dollars, this is not an impulse buy. I waited a couple years until I had made a good start on the insect songs I could hear unaided. But now I am at the point where I want to begin surveying additional species, mainly small meadow katydids in the genus Conocephalus, whose songs are too high-pitched for me to hear without help.
This is a short-winged meadow katydid. I never had heard its song until I used the SongFinder. The song has the typical meadow katydid tick-and-buzz pattern. In this case the song is very brief, lasting one to two seconds depending on temperature. The songs repeat continuously with no gap between them. The buzz has an exceptionally rattling quality, and the 2-3 ticks are very fast. At Mayslake Forest Preserve on a recent day I heard dozens of short-winged meadow katydids whose songs vanished from my hearing when I turned off the SongFinder. Thanks to the stereo design, I found I can locate the direction from which an altered sound is coming and trace it to the singer.
I have done my best to protect my hearing. I avoid louder music concerts, and use ear plugs when necessary, for instance in 2007 when, at their peak, periodical cicadas at mid-day were chorusing so loudly that my ears hurt without protection. Even with these precautions, age gradually has eroded the upper range of pitches I can hear. The SongFinder was created for birders and other natural history enthusiasts for whom sounds are an essential part of our aesthetic.
As I continue to make use of this device in future years I look forward to hearing additional species, such as the slender meadow katydid (though not the individual in the picture, which is a female).