Last year I made a number of a trips to Sylvan Runkel State Preserve which is northeast of Onawa in Monona County. The preserve sits in the Loess Hills of far western Iowa and is the subject of this blog’s header photo. I first traveled to this site in mid-June to look for Strecker’s Giant Skipper (Megathymus streckeri). This species has not been found in Iowa and probably does not occur here, but it does have a number of disjunct occurrences, and a food plant, Small Soapweed (Yucca glauca), that is fairly common in Loess Hill prairies. So, although I did not end up having any luck with that species this time, it was worth a shot, and indirectly lead to me finding the subject of this post. Due to some interesting moth larva that I found on the trip, which turned out to be my personal favorite discovery of 2009, I needed to return to the preserve in the fall. The main results of that trip will be an upcoming post, but in the meantime, here is one of my favorite photos of the year, taken on that trip. It’s a good looking insect and for once the focus and light are pretty good!
This is the Spotted Bird Grasshopper (Schistocerca lineata). It is one of about 50 species in the genus, of which all but one occur in the New World. The one Old World outlier in the bunch is the Desert Locust (Schistocerca gregaria). This is the infamous locust of the Biblical and modern day “plagues” of locusts. Swarms of this species can contain billions of individuals and can decimate crops. Amazingly, migrating swarms of Desert Locusts even made a non-stop trans-Atlantic flight from Africa to the Caribbean and South America in the summer of 1988. Fortunately for US farmers, our species do not form large roving hoards. Our swarming locust, the Rocky Mountain Locust (Melanoplus spretus), is now extinct, which is an interesting story in itself.
The Spotted Bird Grasshopper is one of the most widespread members of the genus in North America. It is also extremely variable in coloration. Some populations apparently feed on a toxic food plant and are extremely brightly colored as a warning to predators. Others vary in coloration depending on the population density of the locusts when they are reproducing. This is especially interesting because the swarming locust species are triggered to produce their migratory, swarming form by reproducing when the species is at high density. So while our species don’t swarm, they seem to have a density dependent reaction that is eerily similar to those that do.
This photo was taken on October 3, 2009. This was the first and only member of this species that I have come across so far.
For anyone interested in reading more about this genus of grasshoppers, the following paper is a bit technical but has good basic information in the introductory sections:
[...] 16, 2010 by Aaron In my earlier post on the Spotted Bird Grasshopper I mentioned some interesting moth larva I found while hiking around the Sylvan Runkel State [...]