Tuesday, September 12, 2017

The Silent Ones

I’ve never written a blog post that does not include some of my field recordings. After all, this is “Listening in Nature!” But did you know there are a few crickets and katydids that do not sing? I’ve had people ask me about them this year, so I thought this might be a good time to introduce you to two non-singers you may find in NE Ohio.

The first is this pretty little European katydid: Meconema thalassinum, the Drumming Katydid. 

It doesn’t “sing” in the same way as other katydids. Instead, it taps a back foot on a leaf! Have I actually heard this sound? No, I have not, but I did find a recording of its foot-tapping performance here. The song illustration in Singing Insects of North American matches the recording quite well.

It’s common across much of Europe, where it's called the Oak Bush Cricket. You’ll find more information about this species if you search for it by that name. They live in trees and do indeed seem to be fond of oaks. 

I typically find them on human structures made of wood, such as a porch, a shed, or a park shelter. The first one I discovered was on my car and it probably had been on the large pin oak next to the driveway. I usually find one on the front porch in mid-July, apparently attracted to the light we leave on until late at night. 

Wendy and I even spotted one on a Cleveland Heights hen house!

According to the Singing Insects of North America, "It lays its eggs in crevices in bark and may have been imported to the United States as eggs on woody ornamental plants. Whatever the means, by 1957 it had become established on western Long Island, New York, and by 1980 it had extended its range to Rhode Island and to Scarsdale and Ithaca, New York.” 

They're not abundant, and they certainly don’t seem to cause any trouble. In fact, gardeners may appreciate that they eat aphids!

My other non-singer also eats aphids other small insects as well. It’s the Carolina Leaf Roller, Camptonotus carolinensis.

The first, second, and third thing you are likely to notice are the antennae. Don’t they seem almost ridiculously long?

They don’t have wings, and their bodies remind me somewhat of camel crickets that we occasionally find in rock formations.

They are “leaf rollers” because they do indeed roll up a leaf to create a shelter. From BugGuide: (The cricket) “bites through leaf in order to form flap. Flap is folded over, edge is pulled down with legs, and then edges are glued together with silk from gland on mouth. Sometimes uses the pods of Bladdernut as a shelter instead of a leaf.” (The original source appears to be How to Know the Grasshoppers, Cockroaches, and their Allies by Jaques Helfer.)

The Carolina Leaf Roller is a native species that’s more common in the southeast. I’ve seen them in southern Ohio, but not typically in NE Ohio. This year, however, I found them in both Medina and Summit Counties south of Cleveland.

And are they ever active! They move quickly, jump extremely well, and can be found in lower vegetation or in trees. In my absolutely subjective assessment, they are adorably cute and absolutely entertaining to watch.

Let’s just take a closer look, especially since we’re not going to take a closer listen to silent crickets. Here's a mating pair.

Both sexes are an attractive golden orange color.

Females have a dark circle around the base of their bodies that reminds me of a wasp or bee.

These photos were taken at Letha House Park in the Medina (County) Park District. I was fortunate to see three of them undergoing what I assume to be their final molt near the edge of one of the restored wetlands on August 1st


This was not a habitat I would have thought to search for them, as I’d only seen them in shrubs and the lower branches of trees, but it certainly made them easier to observe.

 In my next post, I’ll return to insects that sing, but you’ll remember this silent, but attractive cricket and katydid pair until next year, won’t you? 

I’ll close my non-singer post with a photo of one particularly charming female Carolina Leaf Roller. It was from her that I learned how quickly they move and how delightful they are - even if they don't sing!

Thursday, August 24, 2017

Too Much of a Good Thing?

You probably know by now that I’m very fond of coneheads – as in conehead katydids. I suspect that just about anyone who actually sees them loves them. They are gorgeous, sizable insects with long wings, colorful faces, and delightfully quirky cones at the tops of their heads.

But they ARE loud – sometimes excessively so. And there’s one conehead in particular who, while not the loudest, can be a bit of a challenge...

…the Nebraska Conehead.

I’ve included them in two previous posts, but recently I’ve spent more time with this species than in any previous year. And why is that? 

I’ve been doing singing insect surveys in some of the Medina (County) Park District’s beautiful properties. I’ve done nine years of surveys in Geauga, Lake, Portage, and Summit Counties, where Nebraska Coneheads are quite unusual. Their occurrence changes west and southwest of Cleveland, so I expected I’d encounter them in my Medina County study this year. In fact, I've found them at all the Medina parks I've visited.                                                                         

I’ve always been delighted to hear and identify these feisty individuals.  Having spent a great deal of time with so many of them this late summer, though, I confess to having occasional conflicting feelings about hearing them. 

The difficulty for me is not that they’re loud and a little strident. Most coneheads are. It’s that repetitious rhythm! They sing a little slower when the temperature drops and faster on warm, humid evenings, but the pattern remains exactly the same.

I’ve written about how rhythm can be helpful for distinguishing between crickets that look similar. That’s also true for katydids. Here’s a quick Ohio conehead comparison.

Round-tipped, False Robust, and Robust Coneheads are steady buzzes. Round-tipped songs are quite  penetrating, but not too loud until I get somewhat close to them. The False Robust's complex two-pitch buzz is much louder, but it's still bearable for a while. But the Robust Conehead! That degree of intensity is only tolerable from a considerable distance. Approaching him without some kind of hearing protection is absolutely excruciating!

Robust Conehead singing

Here’s an example of the three steady buzzers from loud to louder to loudest. I’ve given each one 10 seconds to state his identity, and you’ll probably agree that’s quite adequate.

Our ever-present Sword-bearing Conehead is described by my singing insect program participants as “the sprinkler.” The Slightly Musical Conehead, whom I find especially charming, has a repetitious pattern with a little more space between songs than the Sword-bearers. Individuals can chorus together as one voice across a wetland. 

 The Slightly Musical Conehead's cone is even longer than that of the Nebraska Conehead!

This track demonstrates ten seconds of each of them:

Nebraska Coneheads combine rhythmic repetition with a particularly strident tone quality. To illustrate the pitch level (high or low) and tone quality (or “timbre” in musical terminology), I’m going to present a most unlikely pair of singing insects: a Narrow-winged Tree Cricket and a Nebraska Conehead.

Narrow-winged Tree Cricket singing

In fact, a Narrow-winged Tree Cricket could be singing right above the Nebraska Conehead in a shrub at the edge of the woods. The cricket’s position would be higher, but his pitch would actually be a lot lower than that of a conehead.

Here’s how to read the accompanying sonogram. You can see along the top of my illustration that the rhythm and phrasing are the same. Below that, however, is the actual pitch (higher/lower) of the two insects. The tree cricket is singing at about 2500Hz and the conehead is up around 10.000 Hz (10kHz), which sounds like a buzz instead of a musical pitch.

So now I’ll return to my field experience with all those Nebraska Coneheads combining their screaming loud buzzes and rock-steady rhythmic repetition. There’s also one additional factor: they all sing in unison with that same rhythmic repetition. This is what truly becomes excessive, as if there’s a conehead singing from a perch on my backpack for the entire length of the trail.

That trail, by the way, would likely be along the edge habitat where they can be found singing from shrubs as well as substantial forbs. They’re not wetland residents and are not necessarily out in the middle of a meadow, but they may actually sing inside the edge of the woods. Here's one that was in the woods with some cold Common True Katydids up above him. It was 55 degrees - pretty chilly for a conehead. Can you hear how slow and labored they all sound?

It’s surprising that something so loud can be extremely difficult to find, and since coneheads in general can be green or brown, I need to watch for both color possibilities. 

In addition, they will most definitely stop singing if you get too close. Why would they advertise to a potential predator? They don’t realize you have no intention of eating them.

Hearing them, however, will not be a problem. In fact, that repetitious rhythm also makes them very effective audiobombs when listening for – or especially recording – other singing insects. Even in the background, a Nebraska’s hypnotic phrasing commands a listener’s attention at the expense of the featured soloist.

But I also know that when they begin to fade out this fall, I’ll miss them. And when the third week of July come around next year, I’ll be as delighted as ever to hear the first Nebraska Coneheads.