Monday, October 3, 2016

Interstate Agility





Labor Day weekend. Fall semester had already begun, and our chances of going back down to Buzzards Roost Nature Preserve in the Ross County Park District any time after Labor Day seemed nonexistent. Park District director Joe Letsche had invited other folks to come to Buzzards Roost  for “All-insect Night” on Friday night, and we were coming from the longest distance. 

As we drove through Chillicothe on our way to the preserve, Wendy and I noticed how different the singing insects combinations are down there. We also observed how we’d come to identify the early September ensemble sound with the Chillicothe area. Our ears told us where we were. 

It certainly doesn’t sound like NE Ohio.  Lesser Anglewings and Columbian Trigs. None of the Black-horned or Forbes’s Tree Crickets I've been recording farther north, but plenty of Broad-winged Tree Crickets. The woods have lots of Tinkling Ground Crickets. There are Robust and False Robust Coneheads along with Round-tipped Coneheads, but none of the Sword-bearing Coneheads that are so abundant in NE Ohio. Having come down to Buzzards Roost four times between late June and mid-September last year, I thought we knew all the singing insects we were likely to find throughout the season.


There was a new meadow area at Buzzards Roost that had just been generously seeded this year. It's up by the park pavilion, adding even more katydid habitat to the already existing field just below it. There are grasses of varying heights, wildflowers, and…lots of coneheads and meadow katydids!


And there were so many meadow katydids! I assumed they were Common Meadow Katydids (Orchelimum vulgare), which prefer drier, upland areas than Black-legged Meadow Katydids and other members of this genus that I know. But I’ve never seen groups of Commons. When I see them at all, there will be one or two here or there.

This, however, was an entire Friday night party in the meadow. These katydids were surprisingly tolerant of our presence and I was able to get close enough for photos. Males and females in close proximity, and mating was definitely on the agenda. 



This female's spermatophore indicates that she's just mated and will be ovipositing in the near future. 



I considered trying to record the singing males, but there was audio obstacle: the nearby Robust Coneheads. 





There was no point in trying to record anything with those ridiculously loud boys so close. I wasn’t particularly concerned about recording, though, as I’d already made Common Meadow Katydid recordings elsewhere in the past few years. 


But when I got home and looked more closely at the photos, they didn’t quite match up with my Common Meadow Katydid expectation.  The eyes were light tan instead of red. The faces were pale tan instead of green. Here's the face of the mystery meadow katydid...


...followed by the face and red eyes of the Common Meadow Katydid.



Their light brown wings were longer than the Common Meadow Katydids I’ve seen, and the female's ovipositor seemed more brown. Here's another comparison: the Buzzards Roost female...


 ...and a Common Meadow Katydid female.




They were in the Orchelimum genus - the katydids' size and the female's curved ovipositor were identifiers but none of them quite matched what I expected to see. 


If anything, they somewhat reminded me of the Dusky-faced Meadow Katydids I’d recently gotten to know. However, these katydids were in an upland meadow, not in a pond edge or wetland. 


Who WERE they? 



When I sent photos to Wil Hershberger, co-author of The Songs of Insects, he recognized them right away. They looked like Agile Meadow Katydids – Orchelimum agile. Except…there were no records of this species in Ohio or any of the surrounding states. According to the range map from Singing Insects of North America, they shouldn’t be north of Tennessee. 
 


We would need recordings and photos of the male’s cerci. If I’d had any suspicion that I was looking at a species that shouldn’t be in Ohio at all. I would have somehow caught the Robust Coneheads and put them in cages in my car until I was done recording!

                                              (Robust Conehead leaving in a hurry)


Too late for that now, though. It was already September and time was short. Fall semester was underway, temperatures would be dropping, and my schedule was packed. Chillicothe is 4+1/2 hours one way, so it's not a quick trip to the next county.


But of course I had to go back. I left right after work on a mid-September Friday afternoon, and Wendy took off early so she could come as well. Would they still be there? Would the males still be singing? 


We went into the grassy meadow almost as soon as we pulled into the driveway. Although there weren’t quite as many katydids, they were there! Now we had to catch one for a quick photo shoot, and they're named "Agile" for a reason.



It took four of us - Joe, Wendy, myself, and Denise, who is holding the individual below - to get the cerci photos, but I got the diagnostic documentation. It seemed like a very good match for Agile Meadow Katydid.




And the males were still singing!






I made recordings of more than one singing male that night and also a male who sang a great deal the next day. The recordings matched as well.


Here’s the song of the daytime singer. The morning was warm and breezy, but he continued to sing even as his vegetation was blowing him back and forth. Look at the rhythmic groupings and spaces between them: a series of "tics" separated from the "whirrs" that follow. There's generally space between everything.


                        (This is the male who's singing in the recording below)

 


Now listen to a Common Meadow Katydid. The "tics" go right into the "whirr" and then start again. It really is audibly different if one listens for the space between the “tics” and the “whirrs” of the two songs, as the Common sounds almost nonstop.






Agile Meadow Katydids had moved north into southern Ohio – yet another more southern species expanding northward.


Although none of the meadow katydid species are large insects, some species have longer wings and others shorter-winged species have long-winged individuals. I saw the Agile Meadow Katydids jump, then fly farther out into the meadow. Is that adequate to get them, over time, from Tennessee across Kentucky and into southern Ohio? How did they cross the Ohio River? 


And when did they arrive at Buzzards Roost? In our trips down there last year and earlier this year, we saw exactly one Common Meadow Katydid in the meadows and shrubby fields. The new meadow area had just been seeded earlier this year. Did katydids elsewhere in the area notice there was a great new diner at Buzzards Roost? 


Naturalist Carl Strang, who’s been surveying singing insects in the 22-county area surrounding Chicago for years, found Agile Meadow Katydids in the Indianapolis area two weeks after I found them in Chillicothe. This, too, is a huge range expansion.


Alas, it is now October 2nd. Although temperatures have been seasonal or a little above normal, the number and diversity of crickets and katydids continues to diminish. If only I didn’t have to wait till next July to continue the investigation!




4 comments:

  1. Awesome work Lisa. These range expansions are fascinating.

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    Replies
    1. Thank you for your help with the mystery, Wil!

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    2. Agree. . Great work and investigation Lisa and team.. .
      Love the story and the Science

      MJD
      Past President
      Aud Soc Greater CLE
      ASGC
      440.708.4120 cell 24/7

      Delete
  2. What you found is totally awesome!

    ReplyDelete