Grasshopper season

Late summer is grasshopper season for me. Even though grasshoppers are around from the first hint of spring to the last days of autumn, it seems like it’s in the hot, dry days of late August and early September that grasshoppers are most notable. Here at our new house, we wander back through fields of long grass when we go for a walk. Each step scatters a half a dozen grasshoppers from before us. They bound away, some just a foot or two, some four or five, and the odd one spreads its wings and flies off much farther.

Many of the non-fliers may still be nymphs, lacking full-grown wings, but all are very proficient jumpers. They owe this to their thick hind legs which contain strong muscles. There are two phases to the grasshopper’s jump: a crouch, and a thrust. As the grasshopper crouches, it contracts its flexor muscle to pull the lower leg tight to the upper leg. In doing so, it also flexes a bit of cartilage that acts like a spring, storing energy. Just before it releases the flexor muscle it contracts the extensor muscle, so that force is already being applied. When it releases the flexor, the “spring” snaps back, the extensor muscle contracts, and the leg kicks out rapidly and with great force. An analogy might be a catapult. As the catapult arm is winched back, it stores up considerable energy. When the winch is released, the catapult arm snaps back. If the body of the catapult was extremely light, and the catapult arm was braced against the ground instead of pointed at the sky, the mechanism would be capable of thrusting the catapult great distance (instead, they put a cup on the end and it thrusts other objects great distances).

If we could jump the same distance relative to our body length that a grasshopper can, we would be able to throw ourselves around 40 meters/yards in one leap from a standstill. At peak acceleration the grasshopper is experiencing about 20 G’s of force – a grasshopper is built to withstand this, but the same force would probably smush a human flat.

I thought I would try to see how many species I could spot amongst our grasses in the meadows. I took photos of everything that seemed to look different, with the intention of identifying them all when I got back inside. It seemed that the vast majority of the individuals I was seeing were of the above species. It was so boldly marked, I didn’t figure I would have any trouble at all identifying it, but I never did find a name. Of the dozen or so photos I cropped and edited, though, I was only able to place labels on four. Four, that’s all!

I pulled out my Kaufman Insects, but for all its fabulousness in other departments, it seems to be lacking in the orthopterans. So I next turned to my Marshall Insects, which helped me to identify (with confirmation provided by BugGuide.net) three of the photos. Then I ran out of print references, and tried browsing BugGuide.net. I was astounded at how many species there were, virtually all of them looking similar to the others. Finally, I searched for a list of Ontario grasshoppers, and found one for the Ojibway Nature Center in Windsor that I was able to identify one more species from. But whew. I hadn’t expected it to require such effort!

I get the impression that identification of grasshoppers from photos can be a tricky thing. For many the field marks are subtle, or you don’t know to look for them when taking the photo (such as with the tree cricket). Of course, as with all insects, there are always some that can only be identified by careful examination of their genitalia or other features requiring a microscope. And then, just to throw an extra wrench in the works, nymphs don’t always have the same pattern as their parents. I had originally thought that the grasshoppers might not be too hard to figure out, but now I’m thinking perhaps they’re a group best left to the experts, like flies or ants.

That said, here’s a couple of the more distinctive species I had. This one was the easiest to ID. It’s a Roesel’s Katydid, also called Shield-backed Grasshopper, Metrioptera roeselii. Its thorax has that yellow-edged flap that seems to fold down over the sides of the body. It’s a recent import from Europe, first found in North America in 1953, in Montreal. It’s now found throughout much of the northeast. Apparently there are both long- and short-winged forms, with the long-winged more common here. This one is a short-winged.

I believe this one is a Red-legged Grasshopper, Melanoplus femurrubrum, although there are a couple of Melanoplus species that share this feature, and I’m not clear on how to differentiate them. Migratory Grasshopper, Melanoplus sanguinipes, would be another possibility, although it seemed like they generally had more pigment in the herringbone pattern of the hind legs. Both Red-legged and Migratory are fairly widespread species, with BugGuide.net having records from coast to coast.

Another Melanoplus species (I think) that I’ve labeled Red-legged but could be something else. This one has more black markings in the wings, and a different pattern to the face. Individual variation? Separate species? I don’t know.

This might be a nymph of yet another Melanoplus species, M. differentialis, Differential Grasshopper. I stumbled across one in the nymphs section of the BugGuide.net Melanoplus page that looked very similar. It stood out from most of the others that I saw in its bright greenish-yellow colour. The majority of the grasshoppers I encountered were primarily brown.

Speaking of nymphs, I came across a couple of these in the grass. They’re the shed exoskeletons of grasshopper nymphs as they molted from one instar to the next. Based on poking around the nymphs page I think that these (as well as the second photo in the post) were late-instar (either fourth or fifth) nymphs of Red-legged Grasshoppers. I gather the black and white arches across the shoulder of the nymph are typical of many Melanoplus species.

Another exoskeleton. Like dragonflies or cicadas, grasshoppers have incomplete metamorphoses, hatching into adults directly out of their last-instar skins, without going through a pupal stage. As nymphs they have wing “buds” but their full-grown wings and full-length antennae don’t appear until the adult stage.

This last one isn’t actually a grasshopper, but another tree cricket, a different species from the one I posted about a few weeks ago. I found this one tucked in the leaves of a milkweed. It seems to be a Black-horned Tree Cricket, Oecanthus nigricornis, identifiable by the dark antennae, dark legs, and markings on the thorax. This species tends not to spend much time in trees, instead preferring raised vegetation in meadow habitat, giving it the alternative common name of Prairie Tree Cricket.