Female Gladiator

by Carl Strang

Last week at Blackwell Forest Preserve, the Roger Raccoon Club hiked to our usual place for tree-climbing instruction. Along the way the kids somewhat nervously were inquiring about buzzing in the tall grass beside the trail. I assured them that the source was not an abundance of rattlesnakes, but rather gladiator meadow katydids. I searched for one to show them, and the first one I found proved to be a female. I had no photos of a female of this species, and took advantage of the opportunity.

Gladiator meadow katydid, female

This species is unique among our northeast Illinois Orchelimum in the shape of its ovipositor.

Though the bottom edge of the ovipositor is curved, as is true for all females of this genus, the top edge is unique in being ruler-straight.

Of course, the fact that there is little or no overlap between the gladiator’s early season and those of other species also helps.

Early Singing Insects

by Carl Strang

To this point in the season I have heard singing males of 10 insect species in northeast Illinois. All but one began earlier than in any of the years from 2006 to 2011. This is consistent with more general insect phenology this year, and is attributable to a mild winter and a warm March which heated the soil earlier than usual. The only species with a later starting date was the spring field cricket, a species I usually hear first while running or bike riding, activities my back trouble prevented during the critical time period. And yet, despite that limited mobility, I have recorded dates for the other 9 species that ranged 5-22 days earlier than in any previous year (4 of the previous records were in 2007, 5 in 2010, 1 last year; they add up to 10 because of a tie). The only other case perhaps worth singling out was the broad-winged bush katydid, 22 days earlier than last year’s previous record. This species is not abundant or widely distributed, and I suspect it has a longer, earlier season than I have realized before. I should make some effort in future years to get a better handle on its starting and ending dates.

Broad-winged bush katydid

For those who may be interested, here are all the first song dates this year so far. Greenstriped grasshopper 3 April, 17 days earlier than the previous record. Spring field cricket 25 May, 20 days later. Roesel’s katydid 29 May, 11 days earlier. Protean shieldback 5 June, 7 days earlier. Linne’s cicada 14 June, 12 days earlier. Gladiator meadow katydid 14 June, 7 days earlier. Dog day cicada 15 June, 5 days earlier. Scissor-grinder cicada 19 June, 13 days earlier. Broad-winged bush katydid 23 June, 22 days earlier. Lyric cicada 24 June, 6 days earlier.

Singing Insect Season Heats Up

by Carl Strang

We have entered the part of the season when first appearances of mature singing insects accelerate. The transition in DuPage County began with the first gladiator meadow katydid singing on June 30. This was relatively early, though 9 days later than the earliest I have heard them in the 6 years of my study.

Gladiator meadow katydid.

I have to append my description of this species’ song. In the past I have said that they seldom include ticks in their song. I have been listening closely this spring, and in fact there usually are very faint ticks between the much louder buzzes. The ticks are variable. Commonly they seem to trail off from the end of a buzz rather than to lead into the next one as is typical of meadow katydids, but sometimes the latter pattern appears. Most of them have an irregular stuttering pattern in the ticks, though occasionally they are regular. The main distinction remains, however, that the ticks are very faint compared to the volume of the buzzes.

The “annual” cicadas of genus Tibicen were led in by a Linne’s cicada on July 3. The next day brought the first canicularis (dog day) cicada song, in my own yard. A lyric cicada debuted on the 11th, and finally a scissor-grinder (pruinosa) offered the first song on July 15. All of these were middle-of-the-road start dates.

Ground crickets also are due this time of year. The first was, as usual, a striped ground cricket, on July 13.

The most recent start-up was by broad-winged bush katydids, several of which were singing their short, lisping day songs at Fermilab on July 15, an early start for the species.

It’s appropriate here to remind you that I can e-mail my free guide to singing insects of the Chicago area to those who request it at my work address: cstrang@dupageforest.com

Common Meadow Katydid

by Carl Strang

Earlier  I related my error in previously identifying DuPage County’s abundant, early-season large meadow katydid as the common meadow katydid, Orchelimum vulgare. This spring I discovered that the correct ID is the gladiator meadow katydid, O. gladiator. It turns out that the two are physically very similar, and there seemed to be some ambiguity in reference recordings of their songs. Last week I was at Meacham Grove Forest Preserve, mainly in search of late season Pachyschelus beetles, about which more will be forthcoming this fall or winter. Reaching Meacham’s west woods requires a walk across the meadow- and wetland-dominated eastern part of the preserve. Where the trail crossed the preserve lake’s inlet stream, I heard rattling buzzes that sounded like the songs of gladiators. This required some investigation, as gladiators elsewhere had finished singing weeks earlier. I found one, and it proved indeed to be a gladiator. But farther along the trail, approaching the pedestrian bridge over Bloomingdale Road, I heard a different song. This was a loud, tick-and-buzz Orchelimum song, but the ticks were more spaced and the buzz was very tight, making it distinct from the songs both of the gladiators I had just heard, and of the black-legged meadow katydids that also had been singing along the stream. This insect was in a dry meadow, singing from the exposed top of a sweet clover plant.

Common meadow katydid 2b

I photographed him, recorded his song, and then reluctantly collected him. He proved to be a common meadow katydid. The cerci, or reproductive claspers, are distinct from those of the gladiator and just like those in reference drawings for the common. The differences are, however, subtle enough under high magnification that I could not have confirmed them on the live insect. Another difference is the shape of the pronotum, the cape-like structure that covers the top and sides of the thorax. Here is the one on the common meadow katydid,

Common meadow katydid cropped 2b

and here is the one on the gladiator meadow katydid.

Gladiator cropped 3b

Again the differences are subtle, but the side of the gladiator’s pronotum has a simple, uniformly rounded outline with no major zigzags or kinks. That of the common meadow katydid has several turns or bends at the front, bottom and (especially) back edges. Incidentally, there is no mistaking a black-legged meadow katydid for either of the others if you see one:

Black-legged meadow katydid 2b

The best news out of all this is that the songs of these three large meadow katydids of DuPage County’s grasslands and wetlands are distinguishable. The gladiator’s buzz is a long, relatively slow rattling sound, with or without a few preceding ticks. The black-legged meadow katydid has a shorter buzz, of a similar sound quality but distinctly faster, always preceded by 2-4 ticks that are rapid, evenly spaced, and run straight into the buzz. Often, ticks and buzzes alternate in a continuous flow. In my limited experience since first finding the common meadow katydid at Meacham, I have noticed two variations in their songs. The buzz can be very tight and fast, reminiscent of Roesel’s katydid . In that variation the song is very different from both the gladiator and the black-leg. However, some individuals (perhaps ones singing at a lower temperature) have a slower buzz that to my ear is just like that of the black-leg. Confusion is prevented by attending to the ticks. In both common meadow katydid song variations, the ticks are irregularly spaced, farther apart, and more numerous than in the black-leg’s song.

For recordings that may help make these differences clear, check out the Songs of Insects and the Singing Insects of North America websites.

Gladiator 1, Carl 0

by Carl Strang

I wasn’t sure how I wanted to start this one. There’s an element of embarrassment, which might be good in a blog despite my personal discomfort. There’s the straightforward information approach, but that would leave out too much. This is a science-themed blog in the end, and I decided that perhaps that is where the emphasis should be. Science is not a body of knowledge. Science is a process, and it’s conducted by human beings, so it gets messy. Errors and false starts, egos and self deceptions all play an important and regular part.

Early in my study of singing insects, on 30 June 2006, I heard the year’s first meadow katydids singing in the dolomite prairie at Waterfall Glen Forest Preserve. I recorded the songs, took photos, and collected one. It was one of the large meadow katydids (genus Orchelimum).

Common meadow katydid 1b

It seemed to me that the habitat, the song, and the cerci (small clasping structures at the tip of the male’s abdomen) of the specimen best matched reference recordings and drawings of the common meadow katydid (O. vulgare). I posed the dead specimen to get a sharper photo than I had gotten of live insects in the grasses.

Common meadow katydid (dead) 3b

From that day until last Thursday I continued to treat these insects as common meadow katydids. The only odd thing about them seemed to be their infrequent inclusion of “ticks” in their song. That needs some explanation. There are a lot of meadow katydid species, and their songs have a tick-and-buzz pattern. Their wings have a sort of comb and file structure. Moving these together slowly produces separate “tick” sounds, vibrating them rapidly produces the buzz. A typical song begins with a few ticks, and ends with a buzz. The many species produce an impressive variety of variations on this basic pattern. All reference recordings of common true katydid songs included several ticks before the buzz. I wasn’t hearing them very often.

That brings the story to last Thursday night, when I presented a fireflies program at north Blackwell Forest Preserve. After I gave the interpretive talk to introduce the program, we walked to the nearby woods to see the light show. On the way we passed a large grassy meadow, in which there were a lot of katydids singing. Their songs were long rattling buzzes, and didn’t quite match familiar patterns. After the program was done I stayed, and found one of the singers to photograph.

Gladiator 3b

Clearly this is a large meadow katydid. In the process of stalking it I impressed the song on my memory. Back home I played my reference recordings, and found a perfect match in the gladiator meadow katydid (O. gladiator). My first feeling was elation, for this species was on my list of those which should be in northeast Illinois, but I had not yet found it.

The more I thought about it, though, the more questions arose. First, there were dozens of these insects in that meadow. How could I have missed them over the previous three years? Second, my impression from reading about gladiator meadow katydids was that they are a marsh species. What were they doing in an upland meadow? McKee Marsh is nearby, but many of these gladiators were singing a couple hundred yards above that wetland. I realized then that I needed to review references for both the gladiator and the common meadow katydid, because I may have identified these incorrectly from the beginning.

I listened, again, to all my reference CD’s and to recordings I had made of “common meadow katydids” in 2006. I found that there was a lot of variation in the reference recordings. All of the recordings attributed to gladiator meadow katydids had the rattling quality I heard Thursday night. Some of the recordings of common meadow katydids had a tighter buzz with no rattle, but others had the rattle, instead. The nighttime songs at Blackwell were very long buzzes, but the reference songs attributed to gladiators varied. Some were as long as those at Blackwell but others were short, like those of common meadow katydids. All of my own recordings proved to have the rattling quality, all had been made in daytime, all had the briefer length.

I had accumulated more books and articles since 2006, and I went through that material. For instance, Elliott and Hershberger in their recent book, The Songs of Insects (a link to their website is in my left blog frame), caution that the common meadow katydid is “Not nearly as common as its name implies” and that it is very similar in appearance to the gladiator. In their entry on the gladiator, they say that it is common, and describe its habitat as “tall grassy areas, often near water.” More enlightenment was provided by Alexander, Pace and Otte in their 1972 paper, “The singing insects of Michigan.” They indicate that the common meadow katydid is a late season species that “replaces” the early-season gladiator meadow katydid around the end of July or beginning of August. However, in Michigan they found the gladiator only in marshes.

Other references emphasized the physical similarity of the two species, to the point where males sometimes interact aggressively with one another (usually members of different species ignore each other). Furthermore, there were indications that they have different song variations for day and night.

So, armed with this information I returned to Blackwell Friday evening. I made a recording of the extended rattling song, and collected a specimen. A careful review of the new specimen and the one from 2006 forced me to conclude that both were gladiators. So, now I tentatively conclude that all the “common” meadow katydids I previously had recorded for July are in fact gladiators. In 2006 my last observation of this species was 25 July, in 2008 was 26 July, apparently ruling out the possibility of common meadow katydids in those years. In 2007 I have a couple notes from the first half of August, but by then the issue is confused by the presence of abundant black-legged meadow katydids (O. nigripes). These have a distinctive appearance, but a full tick-and-buzz song, so now I need to listen and look more carefully to large Orchelimum in August, because at the moment I have no unambiguous observations of common meadow katydids in DuPage County.

So, one lesson is to remember that in science, it’s a good idea to stay open to new information. In field work, look and listen freshly all the time for new things to notice. Hold onto your ideas lightly. Also, take all reference material with a grain of salt. In this case I found many ambiguities and contradictions even among refereed technical publications.

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