Monday, October 21, 2019

The Almost Identical Twin


This past August, my friend, colleague, and mentor Wil Hershberger and I taught a four-day workshop at the Arc of Appalachia in southern Ohio. There was an abundance of singing insects but we also brought some individuals that workshop participants could see and hear up close in the classroom

My contribution was a Confused Ground Cricket that I’d caught in the dirt and dried-up mulch underneath a landscaping shrub during the Midwest Native Plant Conference in Dayton. Though found in much of Ohio, Confused Ground Crickets (Eunemobius confusus) are rare in my immediate area. A chance record the songs, and learn more about this little cricket’s behavior is always rewarding. 




But Wil brought more than just one singing insect, including a katydid I’d read about in Songs of Insects but had never actually seen or heard: 

The Clicker Round-winged Katydid: Amblycorypha alexanderi
 




At the end of the workshop, Wil invited me to take this little katydid home so I could study him and learn to recognize his song. Although this species has been found in Ohio, there are no records for the greater Cleveland region and east/northeast. The closest record was from Ashland County, which is roughly 75 miles southwest of where I live in the Cleveland area. 




Clicker Round-winged Katydids look exactly like Rattler Round-winged Katydids (Amblycorypha rotundifolia), which do live in NE Ohio. 


Rattler Round-winged Katydid, above, and 
Clicker Round-winged Katydid, below.




If any Clickers are this far northeast, I would not be able to distinguish between the two species unless I heard the song. The range map certainly indicates that they shouldn’t be too far away, so I've wanted to be able to identify them by ear. 

Here's the Rattler song followed by the Clicker's song:




How likely am I to hear one singing? Their songs seems quiet, although sonograms indicate that they are louder than one would expect. It’s a matter of frequency – not how often, but how high in pitch – that results in the song being less easily audible to human ears, especially when those ears become older. 

Wil was certainly correct about the opportunity to listen closely to the Clickers’s song and watch this katydid’s behavior. (We just call our resident katydid "Clicker.") I certainly have a better understanding of how to watch and listen for them now. Here’s what I’ve observed so far. 

My microphone reported that the supposedly soft song was indeed much louder than I realized! 


Here's more detail of the Clicker Round-winged Katydid's song. Notice that each individual "click" is  actually multiple wing stroke with a distinctive creascendo and accent at the end. This level of detail is difficult to hear during a long string of "clicks," but it's quite obvious when we can actually see the song.


 Above: three series of clicks. 
Below: the detail of each individual "click."






Clicker sang exclusively at night, and generally only if the lights were off. Some singing insects sing during the day as well, but Clicker certainly did not. (I haven’t heard him actually singing for a while, so I think he has retired.) 


He eats leaves and lots of them! 

 
His favorites are the spicebush and viburnum we have in our back yard. (I believe the viburnum that is his cherished delicacy is black haw.) He’s less interested in red twig dogwood. He’ll eat Virginia creeper leaves, but he has no use for the rough, thick, scratchy leaves of blackberry. He seems uninterested in maple and other tree leaves, but then he’s an understory katydid. 


To my surprise, he will also eat buckthorn, a non-native invasive that’s in every yard on our block. It’s not his first choice, but until later this month, it will be readily available. I will admit that I don’t know what I’ve going to do for him when all the understory leaves have turned and fallen. He has no use for lettuce, though he does appreciate his daily grape and apple slices.


I know Wil gave him iceberg lettuce before he came to our house. Is he now hopelessly spoiled? 

In addition to being his food source, these leaves are where he lives. He disappears into them. When I mist the leaves, he promptly vanishes underneath them. His entire day and night is spent eating leaves, resting on leaves, and hiding among the leaves. Considering that he looks like a little leaf, that’s why he can be difficult to find even in a confined space. It’s no wonder that he and his Rattler Round-winged cousins are so difficult to locate! 



Another interesting thing about this little katydid is his movements, which are slow and deliberate. He often extends his legs one at a time – and one joint at a lime. Every joint seems to be a ball and socket and he can slowly swing his legs independently at unexpected angles that I’ve never observed in a katydid before. His feet cling amazingly and they feel almost sticky because they adhere so effectively to my skin, the terrarium glass, my clothes, the built-in cabinets in the dining room… 



Oh, yes. About his adventures. We thought he only jumped, which he does quite well after giving careful consideration to the possibility. We didn’t realize he will occasionally turn a jump into actual flight until the night he flew across the dining room while I was changing his plants, landing on the glass of a built-in cabinet. I wasn’t overly concerned. He didn’t go very high or far on this or his two other field trips, unlike a Scudderia bush katydid who will fly to the ceiling of the next room if he has an opportunity to escape. 

Clicker routinely climbs onto my hand, but not because of any fondness for me. I’m just a convenient pathway up and out. 


What’s surprising is how very difficult it is to dislodge him! If he becomes annoyed with my attempts to do so, he jumps only my chest and continues to climb. 


Last night, he flew to my ankle and proceeded to climb all the way up my leg until I coaxed him onto my hand and gently dislodged him into his leafy terrarium.



While this all seems rather amusing in the house, I have made note of his movements, his jumps, and his occasional flight. I’ll watch for all of this in the field. Will the Rattler Round-winged have the same kinds of movements? I hope to learn more about that species’ details next year. The Amblycorypha species I know well is the much bolder Oblong-winged Katydid (Amblycorypha oblongifolia), who is larger, more active and more visible. They are stronger flyers that are found in a greater variety of habitats.

Clicker is still with us as of October 21st, and I’ll be looking for more spicebush leaves this afternoon. 


I’m very pleased to have had an opportunity to learn about this intriguing little katydid and who knows? Maybe I’ll find one in the field next year. Thanks, Wil! 



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