Greetings, BugFans,
The BugLady always enjoys photographing these large, handsome grasshoppers as they ricochet off the prairie plants in late summer. She has danced around them in several episodes – in a generalized discussion of their genus, Melanoplus https://uwm.edu/field-station/melanoplus-grasshoppers-redux, and as eye-candy in several summer insect picture collections – but they deserve their own biography.
The Two-striped/Yellow-striped Grasshopper/Locust (Melanoplus bivittatus) is in the short-horned grasshopper family Acrididae. Besides having a few interchangeable common names, it has gone through about a dozen combinations of five genera and a half-dozen species names in the past two hundred years.
If you’re in North America, there’s probably a TSG near you (except for Florida, the Gulf and south Atlantic coasts, the arid southwest, and northern Canada/Alaska). Even with those cut-outs, that’s a lot of territory. Bugguide.net describes their habitat as, “Varies with region, but usually relatively sunny, moist, lush, weedy or meadowy areas. Meadows, prairies, crop fields, road sides, vacant lots, ditch and stream sides … etc.” And urban flower and vegetable gardens. Again – a lot of ground.
Ditto, their menu. The books label them as “polyphagous” (meaning, they eat many plant species). They mainly enjoy leaves of herbaceous plants including grasses, but they’ll also tuck into woody plants, flowers and seed pods. Their diet includes agricultural crops and garden plants, and they are unwelcome on the Great Plains, where their numbers sometimes reach “Biblical” (more about that in a sec). According to a University of Wyoming publication, “A population of 10 adults per square yard in a corn field will defoliate the crop.” And, more alarming, “Experiments indicate that in feeding on spring wheat the twostriped grasshopper wastes six times as much foliage as it eats.”
Some plants produce chemicals that deter insect foragers, but the TSG is oblivious. They also scavenge on dead plants and animals that they find on the ground and will resort to cannibalism when food is scarce.
They do have some dietary requirements – they must ingest linoleic or some other fatty acid in their diet in order to keep their wings rigid. And although they feed on many plants, there are particular species – certain mustards, broad-leaved plantain, red clover and alfalfa, dandelion, chicory, giant ragweed, and a few more – that allow young grasshoppers to grow faster and heavier.
And these are big grasshoppers – females measure up to 2 ¼” and males to 1 ¼.” Adults have a brown to yellowish-green body with a pale stripe on each side that starts at the eye and runs along the top of the body to the wingtips. They have hearing organs on the abdomen, and although one source says that they buzz by rubbing their hind wings against their forewings, another says that they are believed to be silent, though the males produce vibrations. Males are better fliers than females.
A source that the BugLady finds frequently in her research is a blog called “The Backyard Arthropod Project – A Field Guide to the North Side of Old Mill Hill, Atlantic Mine, MI” (http://somethingscrawlinginmyhair.com/). What’s not to like about a guy who says about his blog that, “As of February 2007, it has … turned into a project to document every arthropod that I can find on our property?” The BugLady wishes him a wonderful journey.
He suggests that because of their size and abundance, TSGs might be “one of the kinds that are numerous enough to collect for food. I’ve seen a couple of amusing methods suggested for catching large numbers of grasshoppers like this one. One is for two people to take opposite ends of a big, wooly blanket and run through a field with it, then pick off the hoppers that get caught in the wool. Another is to find a big field, dig a pit about 4 feet deep in it, then have a bunch of people start at the edges of the field and spiral in towards the pit. This drives the hoppers in, until you end up with a pit filled with grasshoppers that you just kind of shovel into bags. Then it’s just a question of pulling off the long hind legs (which can get caught in your throat because of the spines), and preparing using your favorite recipe.” See https://uwm.edu/field-station/entomophagy/ for a BOTW episode called “Entomophagy 101.”
TSGs take reproduction pretty seriously. There’s not much by way of courtship – a male points his antennae toward his intended (preferably a virgin, but he will also pursue a female that has recently oviposited), sneaks up on her from behind, shakes his hind legs in a species-specific way, and takes a“copulatory leap.” She may be agreeable, or she may depart, kick him, or curl up, but if a bond is established, they typically copulate for eight to ten hours. A lot goes on during that time.
Yes, he passes on a series of spermatophores (sperm bundles), thus ensuring the perpetuation of his lineage. But there are proteins incorporated into his spermatophores – “nuptial gifts” that increase her fitness (she may also break down and absorb some of his sperm, for their nutrient value). This, of course, is energetically expensive for the male, and he is not profligate. The long duration of mating also guards her from rival males as she is processing his sperm. A female can receive enough sperm from one liaison to last her whole life.
OK – the BugLady is feeling a little like Dr. Ruth, here.
A week or two later, she lays up to 450 eggs in pods in the soil, or in debris on the ground, or in the middle of a hard-packed dirt road, as the female in the picture chose to do, and they overwinter as eggs, hatching in spring when the earth warms. Eggs laid in mid-summer fare better than those laid later on, because the embryos have gotten further along in their development before cold weather shuts them down. In agricultural areas, eggs are laid in hedgerows and along roadsides surrounding cultivated fields, and the nymphs move into the fields after hatching.
These are not sedentary grasshoppers, and they have boom years in the Great Plains when favorable weather over a few years results in lots of food plants and a gradual population buildup. TSGs respond to the crowding by producing a generation whose appearance and behavior are changed; migratory TSGs have longer wings and lighter bodies, and are gregarious, rather than loners. If they feel crowded, even as young nymphs, they will migrate; in the heat of the day, adults fly (far) downwind at altitudes of 600 to 1,400 feet.
Oh yes – The Grasshoppers of Nebraska tells us that “Unlike many other grasshopper species, it is quick to bite if handled.”
A grasshopper to be reckoned with!
Kate Redmond, The BugLady
Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/