April 7, 2015 at 5:52 am (singing insects, Sound Ideas)
Tags: broad-winged bush katydid, Scudderia pistillata, Scudderia texensis, Texas bush katydid
by Carl Strang
Our bush katydids, genus Scudderia, have some of the most interesting song variations of all our singing insects. They include two “counting” species, with increasing numbers of syllables over a sequence of songs. Often they have more than one song type, and this is true of today’s featured species, the Texas bush katydid S. texensis (back in the days of the Bush presidency I was fond of pointing out that there really was a Texas bush katydid).
Texas bush katydid
The following recording includes two of the 3 song types: single clicks, which I seldom have encountered in the Chicago region, and the characteristic dusk or nighttime song, a series of quick buzzes.
During the day this species produces a very fast, 3-syllable call which I render “dig-a-dig.” It is similar to the daytime song of the broad-winged bush katydid, but the latter has more syllables (sounds like 5, usually) and they are less distinct because they have a lisping quality.
April 6, 2015 at 5:57 am (singing insects)
Tags: Cassin's 17-year cicada, Linnaeus' periodical cicada, literature review, Magicicada cassini, Magicicada septendecim
by Carl Strang
This week’s literature focus is on a single paper, which looked at a significant aspect of periodical cicada biology.
The northern periodical cicada species, Linnaeus’s 17-year cicada on the left, Cassin’s 17-year cicada on the right
Karban, Richard. 2014. Transient habitats limit development time for periodical cicadas. Ecology 95:3-8. He studied septendecim and cassini (our two local species of Magicicada) in New York state. There are several hypotheses explaining why their development times are so long: Pleistocene historical influences (long life span buffered annual climate variation in glacial refuges), predator satiation (some early maturing individuals wait for slower ones to catch up, and long life spans facilitate this), low nutrition forces long development, and increased fecundity (17-year species have been shown to be more fecund than the more southern 13-year versions). Here he examined the possibility that habitat quality changes rapidly enough to put an upper limit on such advantages of long lifespans. Though past studies pointed to possible advantages of edge trees, here he compared weights of newly eclosed adults from edge vs. forest interiors, finding the former to be only slightly (4.9%) heavier in septendecim but no difference in cassini. He took density of emerging nymphs as an indication of habitat quality. Changes in study sites were significant between emergences, enough to limit any advantage of longer life. He commented on the Raccoon Grove study site in Will County, once one of the highest-density populations known, mentioning that they plummeted over just a couple sequential emergences, first because of Dutch elm disease killing host trees. Karban and Yang visited that site in 2007, hearing one chorus but finding no emergence holes or nymphal skins.
March 25, 2015 at 5:53 am (singing insects)
Tags: Bendix Woods, bioblitz, Evie Kirkwood, Japanese burrowing cricket, Jim Louderman, Velarifictorus micado
by Carl Strang
Last September, several of the participants in St. Joseph County’s Bendix Woods Bioblitz were interviewed for that park district’s series of nature-related television programs. Evie Kirkwood, a national leader in the heritage interpretation field, was the interviewer. I was one of the interviewees. My segment recently was televised, in a program that included another on pollination, and one featuring the Field Museum’s Jim Louderman, who also will be participating in our Centennial Bioblitz in DuPage County in June. The program can be viewed HERE. The segments can be selected individually.
The first stop of my segment had both fall field crickets and Japanese burrowing crickets singing, but the latter’s song is more prominent in the audio pickup. I did not mention the Japanese burrowing cricket because I did not confirm its identity until the next day.
Japanese burrowing cricket at Bendix Woods
March 24, 2015 at 5:51 am (singing insects, Sound Ideas)
Tags: Chortophaga viridifasciata, green-striped grasshopper
by Carl Strang
We are within two months of the start of the singing insect season in the Chicago region. Opening day is marked by the first displays of the green-striped grasshopper.
Male green-striped grasshopper (females usually are green)
These grasshoppers get their early start because they overwinter as nymphs, and so can mature quickly in the spring. Their displays, which qualify them as singing insects, consist of short flights in which they rattle their wings, producing a buzzing sound:
That this is a display is demonstrated by the fact that when they are flying to avoid the pursuit of a possible predator, they do not make that sound.
March 10, 2015 at 6:02 am (singing insects, Sound Ideas)
Tags: Amblycorypha oblongifolia, common true katydid, oblong-winged katydid, Pterophylla camellifolia
by Carl Strang
The name “katydid” has come to cover a wide range of singing insects, most of whose songs do not sound anything like that name would suggest. Today I wish to share recordings of two species which seem to say something like that name. Both are common in the region. First up is the oblong-winged katydid:
The next recording is of a common true katydid. Though this individual has only two syllables per song, some have three to match the syllables in “katydid,” and others have 4 (“katy didn’t”) or more.
Common true katydid
February 25, 2015 at 5:09 am (singing insects, Sound Ideas)
Tags: Anaxipha exigua, confused ground cricket, Eunemobius confusus, Eunemobius melodius, melodious ground cricket, Neonemobius palustris, Say's trig, sphagnum ground cricket
by Carl Strang
Today I share recordings of 3 ground crickets. The first of these, the melodious ground cricket, is not very well studied, and recordings of its song are not commonly available.
Melodious ground cricket
The song is a fairly loud, steady trill with a pleasant tone:
That song is most like that of Say’s trig, which can occur in close proximity as both are wetland species. When such is the case, the distinction is clear. Here is a recording of Say’s trig for comparison:
The recordings are a little misleading in that both species can be equally loud. Next up is the sphagnum ground cricket.
Sphagnum ground cricket. This species does not occur away from sphagnum moss.
The song is higher pitched and more rapid than that of Say’s trig, which again often co-occurs.
The final species has an interrupted trill, unlike the continuous singing of the previous crickets. The confused ground cricket usually is found in drier portions of woodlands than the more swamp-dwelling melodious ground cricket.
Confused ground cricket
The song is about one second on, one second off. If there are few other sounds, you may hear some stuttering during the “off” intervals:
February 19, 2015 at 6:42 am (singing insects)
Tags: singing insects guide
by Carl Strang
Each year I update my guide to the singing insects of the Chicago region. This year’s pdf edition is up to 3.5mb, with the addition of a number of new species pages and corresponding reduction in the hypotheticals section.
If you are not on the mailing list and wish to receive a free copy, send an e-mail request to my work address, firstname.lastname@example.org
February 11, 2015 at 7:01 am (singing insects, Sound Ideas)
Tags: black-legged meadow katydid, long-spurred meadow katydid, Orchelimum concinnum, Orchelimum nigripes, Orchelimum silvaticum, stripe-faced meadow katydid
by Carl Strang
Today I am sharing recordings of 3 species of large meadow katydids (genus Orchelimum). One way or another their songs all fit the ticks-and-buzz pattern characteristic of their group. I will order them idiosyncratically, by how well I can hear them in the field. I will be interested in any comments on how well you can hear them in these recordings. The first is our most common species in the genus, the black-legged meadow katydid O. nigripes.
Black-legged meadow katydid
This was a very warm individual who was rushing the ticks. I render the pattern tickety-buzz, as there usually are 3 ticks leading directly into the buzz, with a brief pause before the next set. This species usually can be found in or near wetlands. I can hear its song unaided without any trouble.
Next up is the long-spurred meadow katydid, O. silvaticum.
Long-spurred meadow katydid
Here the ticks have much the same quality as the buzz, several very brief rattles that merge into the rattling buzz. This is a katydid of woods edges and adjacent areas with tall herbaceous vegetation. I can hear some of these unaided in the field, on a calm day without other competing sounds, or when there are plenty of reflecting surfaces, but usually I need the SongFinder pitch-reducing device to detect them. I can hear this recording clearly, though.
Finally, here is a species I first encountered this past season, the stripe-faced meadow katydid, O. concinnum. It is a specialist in certain kinds of wetlands, and is much less common than the others.
Stripe-faced meadow katydid
This one I can’t hear at all from more than a few feet away, and I can barely hear it in this recording. I really need the SongFinder for this species. The ticks are more numerous, more separated, and more irregularly spaced, than in the black-leg.
January 30, 2015 at 6:50 am (singing insects, Sound Ideas)
Tags: Allonemobius fasciatus, Bendix Woods, common true katydid, fall field cricket, Gryllus pennsylvanicus, Japanese burrowing cricket, Pterophylla camellifolia, striped ground cricket, Velarifictorus micado
by Carl Strang
One of the unexpected findings from the field season just past was the discovery of Japanese burrowing crickets at Bendix Woods in St. Joseph County, Indiana.
Japanese burrowing cricket
As described earlier, there is a well-established population of this exotic species in the gravel-filled medians dividing parking lots and drives in the central part of the park. They are well buried, and it was only their distinctive songs that gave them away.
The chirps are distinctly buzzier than those of the fall field crickets that were singing nearby. Here is a fall field cricket recording from 2006 for comparison.
Listening to it, I’m getting a warm reminder of summer. Common true katydids, a striped ground cricket, and wall-of-sound tree crickets and other ground crickets are in the background.
January 16, 2015 at 6:59 am (singing insects, Sound Ideas)
Tags: Anaxipha exigua, Cuban ground cricket, Fullersburg, Illinois Beach State Park, Mayslake, Neonemobius cubensis, Neonemobius variegatus, Say's trig, variegated ground cricket
by Carl Strang
One of the highlights of the field season just past was finding variegated ground crickets, a long sought species, right under my nose, as described earlier.
Variegated ground cricket
Here is a recording I made in 2011 in the lawn at Mayslake Forest Preserve. I have trimmed out all but the critical end portion, which includes the abrupt end of one trill and the crescendo beginning of another:
I had made the incorrect assumption that these crickets, living in cracks and holes in the lawn, were Say’s trigs. Here is a recording of one of the trigs from nearby Fullersburg Woods Forest Preserve. The ending likewise is abrupt, but the next trill has a “chuwee” beginning.
In both cases the trills are extended, longer in the trig as a rule. A third species worth comparing here is the Cuban ground cricket. I have not encountered this species in the Chicago region, yet, but I need to be alert for it. Previously known only as a southern species, Lisa Rainsong has found it to be common in the Cleveland area. Ecologically it seems to resemble the variegated ground cricket in liking wet areas near lakes, rivers, and marshes, but is active on the surface rather than remaining out of sight in gravel or in soil crevices. Here is a partial recording of a Cuban ground cricket living in a terrarium in Lisa’s home:
The repeated brief scratches or chirps are from a striped ground cricket in another terrarium. The Cuban ground cricket, a member of the same genus as the variegated, likewise has a crescendo beginning, an extended high-pitched trill, and an abrupt ending. The pitch is just a little lower than that of the variegated, but otherwise they are much the same.
A final note on this topic is that my analysis allowed me to identify a recording from Illinois Beach State Park as belonging to a variegated ground cricket.
The singer was located beneath this vegetation, a few steps from the Dead River. I could not find it, and now realize that it must have been beneath the surface.
Here is an excerpt from the recording (you may need to turn up the volume):
All of this has me primed to document variegated ground crickets elsewhere in the coming season, and to be alert for Cuban ground crickets.