Sunday, September 13, 2020

Amblycorypha Choristers

 



It’s the Year of the Oblong-winged Katydid in NE Ohio! I have never heard and seen so many Oblong-wingeds during field season. Amblycorypha oblongifolia numbers vary from year to year, as do the numbers of their little cousins, the Rattler Round-winged Katydids (Amblycorypha rotundifolia.) 
 
But in July and August of 2020 they were by far the most abundant katydid in the woodland edges, wetlands, and meadows.Their numbers were especially surprising far out in the open, as they’re more typically in shrubby edges and woodland understory.

Since they appeared to outnumber all the other singing insect species except for the ever-present Carolina Ground crickets, this clearly is the year to profile these beauties.
 

In NE Ohio, we typically see more of the Scudderia genus bush katydids – especially the very common Curve-tailed Bush Katydid- than the Oblong-wingeds. Therefore, people may confuse them, especially with so many Oblong-wingeds out in the meadows and wetland edges this year.

They’re both large with long, green, leaflike wings. Here’s a Curve-tailed Bush Katydid's very long, relatively slender wings:


Now look at the Oblong-winged Katydid's wing shape. There is indeed a distinctive bend in the upper wing and they're also wider and a little shorter.

 

In addition, both the male Oblong-winged Katydid and the male Rattler Round-winged Katydid have a dark stridulatory field where the male's wings attach to his thorax. This is where the wings' file and scraper produce the insect's songs. The dark color in these two species make a quick gender determination easier.
 


Male Oblong-winged Katydid.

Katydids in the Amblycorypha genus are called “round-headed katydids, and it’s true! Look how rounded their heads are – very different from the Scudderia bush katydids.


Male Oblong-winged Katydid

The Oblong-winged's song can be described as an emphatic Scritch-IT?! Scritch-it-IT?! 




When the temperature drops to what katydids would consider to be chilly after sunset (low 60s or perhaps upper 50s) their songs slow considerably. These are cold-blooded individuals and they can't move -and therefore, sing - as fast at those temperatures and their pitch won't be as high. One recent night at 61 degrees, I noticed that I was actually hearing more wing strokes than usual. Do they always have this many wing strokes that I didn't hear at a faster tempo, or was this unusual? 

Oblong-winged Katydid at 61 degrees with a chilly 
Sword-bearing Conehead in the background.



Unlike this year, I typically hear multiple males singing only if there is a female nearby. Elegant and sometimes even a blueish green, I’ve often found a female posing motionless on a leaf while hearing males all around her. Each one makes his best enthusiastic effort to successfully audition with his song while she is onstage. 
 
Female Oblong-winged Katydid. Notice her long, curved ovipositor.


Although woodland edges, understory, and occasionally wetland edges are the expected places to find these katydids, in this exceptional year their exclamatory songs have resounded in a chorus from almost every katydid-friendly habitat. 
 



The Rattler Round-winged Katydid, Oblong-winged’s smaller relative, is not a species I frequently find in NE Ohio. They seem to appear in scattered locations, but never consistently or in large numbers. Their occurrence varies annually, and in some years I may not find them at all. I have to remind myself that worry may be premature. 
 
Male Rattler Round-winged Katydid

They, too, are woodland edge and understory residents. While Oblong-wingeds occasionally appear in meadows and can be expected in wetland edges, I almost never find Rattlers elsewhere.

Their very high, soft, delightful songs are not as easy for some of us to hear. Here’s an example.





At one property I surveyed this year, I saw a couple of Rattler nymphs in July and did not see any again. I thought perhaps the multitudes of non-native, invasive Chinese mantises had eaten them all, as a katydid make a fine meal for one of these “preying” mantises.

But to my delight, I finally heard, then saw, a Rattler perched right out in the open on top of a low, dense mound of blackberry. Here he is, and here's his song:
 




Within a couple of minutes, I realized that two more males were nearby on the same thorn-filled stage. Rattlers often hide under the leaves but occasionally sing from an upper surface to advertise for females.
 

 

Like male Oblong-wingeds, male Rattler Round-wingeds also have a dark stridulatory field. Both species have round heads, as they are Amblycorypha.



I brought one of that trio of male Rattler Round-wingeds home to compare with the Clicker Round-winged Katydid I was given last year. (See my post about this species for a visual comparison.) Clickers (Amblycorypha alexanderei) don't seem to be present in NE Ohio. They’re not a species I ever hear and the two are visually identical so I wouldn’t be able to tell by sight. I had hoped for an opportunity to study a Rattler’s behavior after living with the Clicker last year, but could not assume that finding multiple Rattlers would even be possible.

The Rattler does look identical to the Clicker and his behavior is very similar. He’s not at all timid or nervous, appearing to move with the elegant restraint of a Baroque dancer among the lush vegetation in his butterfly cage. 
 
While attending to the plants in his cage on the dining room table, though, I can’t assume he won’t decide to travel outside his cage any more than I could assume this of Clicker. He may suddenly spring in an athletic jump that propels him airborne into beautiful fluttering flight across the dining room. Or perhaps he’ll simply jump onto me, attaching himself to my cheek with his scratchy, tiny feet – or completely surprise me by leaping up into my hair, as the larger Oblong-winged has also done.
 
Unintentionally accessorizing with an Oblong-winged

 

The Oblong-winged’s legs and wings are significantly larger. He has easily jumped from his butterfly cage directly to the top of my head. The evening he decided to fly, he didn’t take just a quick trip from the dining room table to the top of the lower window. He took a vacation. Using the same jump-and-extend-the-wings takeoff as the Rattler, the Oblong-winged repeatedly circled the dining room and then confidently flew into the hallway, ultimately landing at the edge of a bathroom shelf. It was easy to see how one could fly around a meadow or wetland to suitable vegetation while the Rattler would stay hidden in the understory.


By the end of August, the number of Oblong-wingeds was beginning to diminish to more expected levels. Life for crickets and katydids is short, and they are frequently predated or eaten. 

I know that frost and ultimately a freeze will come to my Geauga County survey sites before the end of singing insect season occurs closer to Lake Erie’s warm water. The meadow-dwelling tree crickets matured later than usual this year and are now becoming the center of the singing insect sound stage. Jumping Bush Crickets just began to sing two weeks ago and the late-season Round-tipped Coneheads have only recently reached adulthood.

Please, September, be kind…
 

Sunday, July 26, 2020

Worried...or Impatient?


Broad-winged Bush Katydid male

In recent weeks, people have been writing and posting their worries about there being no crickets this year. I’ve reassured them, as I do annually, that it’s simply been too early for crickets.

But I realized last night that I’m really not immune to such concerns. I have a lot of information and experience, and I know when to expect each of our NE Ohio cricket and katydid species to mature. If they’re late, I start to worry. Is it just the weather? Was it severe thunderstorms washing away and drowning all the nymphs? Pesticides in neighboring fields or developments? Deer damage? Human damage? Insect apocalypse? Climate chaos? There are different collections of concerns for different habitats, but I have a broad repertoire. 

I rather expected that singing insects might be behind schedule this year because of the prolonged cold weather and even snow in May. But I also thought that perhaps the steamy weather in parts of June and July would hurry things along and it would all even out.

Gladiator Meadow Katydids typically mature during the last week of June or the first week of July, but their expected habitats were silent. Broad-winged Bush Katydids are right behind the Gladiators in early July, but I didn’t hear a single individual. In fact, I wasn’t seeing many katydid nymphs, either. I would have expected Carolina Ground Crickets in the second week of July, but there still weren’t any singing in our backyard and they were only just getting started in the field. And where were the Striped and the Allard’s Ground Crickets?

Of course. I knew it. They were all washed away in storms, just as I’d feared. Except… there were still tiny Spring Trigs singing…they didn’t get swept away by anything.

Then it occurred to me that perhaps each time there was a hot summer and katydids and crickets matured early, I tended to make that my new baseline. If singers were not onstage by those early dates, they were late.

Here’s what actually happened in mid-July.



I’m out in the field most nights because I’m doing a survey for the Geauga Park District in NE Ohio. The survey compares species in the NE, SE, and SW corners of the county. Each week, I visit three parks and one property that’s not open to the public, so I’m comparing and fussing over four different locations. 



There were tiny meadow katydid nymphs (above), and sometimes I’d see Scudderia bush katydid nymphs and Amblycorypha nymphs (Rattler-Round-winged and Oblong-winged Katydids - below). I don’t know how they manage to survive storms and heavy rainfall but singing insects have been around since dinosaurs walked the earth. 
 


One property had no adults except for Spring Trigs and Roesel’s Katydids - a small, attractive European shieldback katydid that doesn’t seem to cause any problems for our native species. 


Roesel's Katydid female

But this property should have had lots of Gladiator Meadow katydids and Broad-winged Bush Katydids! Where were they?

Then the next week– suddenly, they were everywhere! No social distancing whatsoever! They were just a little late.



Gladiator Meadow Katydid male

Every Gladiator’s song seemed to end where another’s began, creating waves of insect song. 




In addition, I don’t recall ever hearing so many Broad-winged Bush Katydids in one location. I hadn’t seen their nymphs, so I had no idea how many of either species might actually be present. What a joyful relief! 

Gladiator Meadow Katydid male

The Broad-winged Bush katydids at this property were so numerous that I was able to study them more closely than usual. 

Broad-winged Bush Katydid female

Their songs are more complex that many katydids. Notice that their song series starts with just two or three “tsips” and adds one more each time: 3, then 4, then 5, then 6, and at least for this group, stopping at 7. I modified this sonogram so you could see the “counting” more clearly. Each song statement seems to get louder and more emphatic as the count increases.
 




But this year, I could observe more of the process. With multiple males close to each other, I could hear how one would start singing and another would follow right behind him. After a period of silence, one would begin again and another would immediately follow as if singing in a competitive canon. 



Excellent!  At least at this location, Gladiator Meadow Katydids and Broad-winged Bush Katydids were absolutely abundant. But what about the other park properties where they were expected but currently missing?


Just two nights later, I slowly and cautiously made my nocturnal way through a wetland area in SE Geauga County. It has excellent habitat for Gladiators, but I hadn’t seen or heard any sign of them - only a couple up in the timothy near where I parked my car. Now, however, singing adults were exactly where they should be – in dense vegetation and boot-sucking mud that made seeing them almost impossible.

Gladiator Meadow Katydid singing from hiding  in wetland vegetation

Finally, Curve-tailed Bush Katydids typically mature a little after the Broad-winged Bush Katydids and the two species can be heard together throughout July.  They are by far the most common Scudderia species in NE Ohio. I’d observed Scudderia nymphs at some of my survey locations, but they didn’t appear to be growing very much. 

Scudderia nymph: his wings are not yet fully grown.

As with both the Gladiators and the Broad-winged Bush Katydids, there seemed to be a Curve-tailed Bush Katydid festival night when many of them appeared to mature at once. In SW Geauga County on the 17th, there were more Curve-taileds than I think I’ve ever heard at the same time.


Curve-tailed Bush Katydid adult female

Wendy and I watched closely for katydids that were molting on both the 17th and 18th, as we didn’t want to inadvertently damage any individuals who were this vulnerable state. It’s a good thing we were careful!



Curve-tailed Bush Katydid has just molted and is eating its shed exuvia


I’m finally starting to hear Carolina Ground Crickets and heard the first Striped Ground Crickets last night. Maybe they didn’t get washed away, either.
But what about the Sword-bearing Coneheads? Where are they? Where are the nymphs? Shouldn’t the one in the photo below be singing by now, or have the invasive, non-native praying mantises eaten them all along with the other missing katydids?  



Should I be worried? 

My own notes say they should mature in the third week of July. July 20th is a reasonable expectation. They can begin singing even a week earlier when it’s been as hot as this July has been so far.

July 19th, and I still had not heard a Sword-bearing Conehead. I'd only seen a few conehead nymphs.

Sword-being Conehead male nymph

Was I legitimately worried, or just impatient? 


First Sword-bearing conehead I saw this year (female)

Then on July 20th, the first Sword-bearing Coneheads were singing!




What I think I'm seeing and hearing is that some species are more or less on schedule and others are somewhat late. I just may not know for a little while longer whether there are reasons for concern about any particular species or locations. For now, though, I'll try to set aside my subjective worrying and just observe, document, and learn. 


  Curve-tailed Bush Katydid female completing her molt and inflating her adult wings