Shield-backed Katydid, TETTIGONIINAE

Excerpts from Jim Conrad's
Naturalist Newsletter

from the November 29, 2009 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins; limestone bedrock; elevation ~39m (~128ft), N20.675°, W88.569°; central Yucatán state, MÉXICO
AN (ALMOST) WINGLESS SHIELD-BACKED KATYDID

One morning this week just after dawn I reached for a shoe and found sitting on it an orthopterid -- a member of the insect order Orthoptera, embracing crickets, grasshoppers, katydids, etc. I carried both shoe and insect outside and took the photo shown at the top of this page.

Can you see what "bugged" me about this critter? I couldn't understand how it could have that short, scythe-like, egg-depositing ovipositor, indicating that it was an adult, yet also have no wings. Moreover, grasshoppers tend to have short ovipositors like this one's, but their antennae nearly always also are short. Knowing I'd be asking Bea in Ontario for help, I got her a nice close-up, which you can see below:

Shield-backed Katydid, TETTIGONIINAE, head

You might be interested in Bea's procedure looking for a name. First she had to decide whether this was a cricket, katydid or grasshopper. As her deductive process got underway she boned up on the differences at BugGuide.net and let me in on what she was learning:

GRASSHOPPERS:

the females' ovipositors are short, horn-like appendages, NOT slenderly sword- or spear-like.
no tympana (ears) on their front legs, OR if they do have tympana, they are at the base of each side of the abdomen (at least in our species).
front wings leathery and thick (if they have wings), and compressed from side to side when folded.
noise-making (stridulatory) apparatus in our species (if preasent) isn't easily seen, and usually involves the hind legs and the front wings.
If they stridulate, it's usually a raspy non-musical sound.
nearly all species have antennae much shorter than the body.

KATYDIDS:

the ovipositer is rigid and elongated, looking rather sword-like
wings as in grasshoppers, except in many the front wings are often much broader, giving the insect a leaf-like appearance.
stridulatory apparatus is a membranous area near the base of the top of the wings, with obviously swirled or curved veins
tympana usually present on the tibia (lower long segment of the front leg near the "knee")
sounds varied, but often raspy or ticking and non- musical
antennae are very long and slender, usually longer than the body.

CRICKETS:

best told from Katydids by being flattened top to bottom instead of side to side
ovipositor more slender and needle or spear-like, with the tip usually somewhat swollen
front wings usually more membranous and in the males the swirled veins usually cover most of the entire top of the wings
sounds tend to be musical "chirping," though may sound like some grasshoppers or katydids
more soft-bodied than most katydids and grasshoppers

There are individual exceptions to most of the traits above (such as a couple of species of Grasshopper with long antennae), but the generalities stated usually work and exceptions tend to be few.

After a couple of days of hard work, Bea wrote:

"Here is what I'm sure of so far: Order: Orthoptera (Grasshoppers, Crickets, Katydids) Suborder: Ensifera (Long-horned Orthoptera) Pretty sure: Family: Tettigoniidae (Katydids) I'm guessing Subfamily Tettigoniinae - Shield-backed Katydids"

And that's as far as we got. We got our heads more organized about the Orthoptera, though.

from the June 5, 2016 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins; limestone bedrock; elevation ~39m (~128ft), N20.675°, W88.569°; central Yucatán state, MÉXICO
SHIELD-BACKED KATYDID ENCOUNTER #2
My friend Iolanda brought me an envelope in which she'd plopped a plump, grasshopper-like critter found on a wall in a room she was cleaning.

"It doesn't fly, doesn't jump, just crawls along like something is wrong with it, and I've never seen anything like it," she explained, concern in her face for what seemed a sick insect. Below, you can see the captive, whose body was about two inches long (5cm):

I couldn't figure it out. One confusing feature was that, though it looked like a fat grasshopper, its antennae were too long and slender. However, what really caught my eye was that it didn't seem to bear wings. Below, look at the top view of its body:

Shield-backed Katydid, TETTIGONIINAE, top

It does have those transparent-looking veiny items extending from behind the saddle-like area behind the head -- the prothorax -- but they certainly aren't large enough to propel such a thick, heavy creature through the air. A much closer look at them and the prothroax is shown below:

Members of the Grasshopper/Cricket/Katydid Order, the Orthoptera, undergo incomplete metamorphosis, so what hatches from the egg is a much smaller edition of the adult, but without wings and sexual parts. As the immature stages, referred to as nymphs, mature, slowly wings and sexual parts become more apparent. The veiny things look like baby wings on a grasshopper nymph, but the insect's body definitely looks like that of a mature adult. We've seen wings lacy-veined like this on katydids, so could this be a katydid? I was glad to have volunteer bug identifier Bea in Ontario to ship the pictures to, because this surely would take a lot of study.

And, it did take awhile before the "I found him!!" letter came in. Bea began by outlining her approach to discovering the identity:

It has long antennae, so it is "long-horned"
It has spines on the front legs, so I think it is predatory, using those spines to hold prey
He has puny back legs so not a big jumper
Is he wingless or nymph? I'm thinking wingless

These and other points led her to the Shield-backed Katydid group and, once she'd figured out that, she found someone else's picture of the same species, also photographed in the Yucatan Peninsula, "on the edge of a hammock mangrove forest." You can see that picture by Small Wonders at http://www.projectnoah.org/spottings/8716113

So, it belongs to the Katydid Family, the Tettigoniidae, and the Shield-backed Katydid Subfamily, the Tettigoniinae. These are both large groupings. Trying to figure out the genus, I began mining online literature in Spanish, since Bea doesn't speak Spanish. The only new information I came up with is that one genus of the Shield-backed Katydid Subfamily often is wingless, and that's the genus ATLANTICUS. Three Atlanticus species are listed for Mexico, and others occur in extreme southern Florida, so the genus Atlanticus seems like a good first guess. There's even an Atlanticus nigromarginatus, which sounds about right for a Shield-backed Katydid bearing such black lines on its prothorax. However, no pictures of that species can be found on the Internet.

And then, as I burrowed through the Internet, I stumbled upon something interesting that left both Bea and me a little shame-faced. Soon after I first arrived here in 2009 I found and photographed the same species -- and Bea identified it as a Shield-backed Katydid. {That entry provided above}

That previous find was a female with an egg-laying ovipositor at the rear of her abdomen, and this week's one is a male, so now we have both sexes.

However, we still don't know for sure the genus and species, and I'm thinking that there's a fair chance that this may be an undocumented one, maybe one with no name. However, by parking our pictures here with the keywords "tettigoniinae Atlanticus," now there's a better chance that an expert someday will stumble upon our page, be happy to see our documentation, and enlighten us as to its name, if it has one.