Tuesday, July 24, 2012

Two recent (very successful) trips

On July 16th we drove up to the Harold Alexander WMA in Sharp County. This is one of our favorite places. In only 60 miles or so it gets us up out of the Delta and into the entirely different habitats of the Ozarks. We went up because we were getting cabin fever hiding out from the heat, and the forecast for the day was, that it was not going to be terrible: Partly cloudy and low 90s. When we got there we stopped at all our favorite places, and it was pretty empty of life. Very few butterflies, very few flowers blooming, very few robber flies. But we are into grasshoppers right now, and they are not as affected by the heat, and in the sparsely grassy places where we found them last year, two small slant-faces were out, Spotted-wing and Pasture Grasshoppers, and out on the dirt roads we found the first Wrinkled Grasshoppers of the year. These will soon be common everywhere. They are big grasshoppers, I think rather handsome with their big heads and bulky bodies.

Throughout the country, I read, they tend to have red wings, but a small percentage have yellow wings (the front wings on a grasshopper are sort of leathery covers for their flying wings, which are the ones with the sometimes bright butterfly-like colors that are concealed underneath until they take off).  In Arkansas, however, this is reversed, and ours have dark yellow wings, except for about every twentieth, which surprises you by having bright red wings when it bursts up from your feet.

These were not the only new-for-the-season grasshoppers out. Also along the road we saw the quite charming Three-banded Range Grasshoppers, also large, with very nice marking. The dirt roads here are the only place we have found this species so far.

Even on the poorest days we never fail to see something extraordinary and unexpected at Harold Alexander. This day it was a robber fly, Microstylum morosum. It is almost two inches long, making it huge for a powerful predatory insect. It is one of the most dramatic insects I know of. They are found in open prairie or prairie-like areas in Texas and Oklahoma, with a few extending into extreme southwest Arkansas, at places like Grandview Prairie and Terre Noire. Most robber flies wait for a prey insect to fly overhead, then fly up and snatch it out of the air like a falcon. But these hunt more like accipiters, racing along close to the ground until they frighten a grasshopper into flight, which they then easily overtake and capture. A couple of years ago my friend Jeff Hoeper found a dead one near his cabin on the eastern shore of Lake Norfork in Baxter County. He lives in woods, not prairie, and his cabin is nearly on the Missouri border, more to the east than the west side of Arkansas. How he could possibly find one there was a mystery, and now the mystery is increased, because when we saw this one we were in deeper woods, and even farther to the east. But there it was, with its glowing green eyes, terrifying the grasshoppers along the dirt road where we had parked our car. Check out that beak, loaded with neurotoxins. Don't try to catch this one with your fingers.

July 22nd we drove up to Mountain View, in Stone County. Cheryl had booked a cabin for one night at the Folk Center. That way we could drive the 150 miles up Sunday morning, do stuff in the afternoon, do stuff the following morning, then drive home. We stock-piled enough food for our two cats, closed a door so they were in opposite sides of the house and couldn't tear each other's eyes out, and went. We didn't bother to look at the weather report.

We only take back roads if possible. So we went through Black Rock, Strawberry, Cave City. At Melbourne instead of turning off to go down the windy road to the White River and Mountain View, we kept on straight through and went to Calico Rock. We crossed the bridge into Stone County and came down 5 a little way and turned off at Culp Road and stopped by one of our favorite glades. Glades are wonderful specialized insect habitats where in the past we had gone to see the localized Arkansas population of Large Grassland Tiger Beetles (Cicindela obsoleta). The glade is a big open area with flat rock outcroppings, a kind of limestone pavement. Trees can't grow there, but there are small shrubby plants and low grass tufts, with lots of bare sandy soil. It was evidently too early in the year for the big tiger beetles, because we didn't see a one, but the place, even in the nearly 100-degree weather, was hopping with grasshoppers. Wrinkled Grasshoppers were out in numbers. And then, to our surprise, we found Rock-loving Grasshoppers, which evidently is a sign that, for all the limestone, the soil here is acidic. These are the famous lichen grasshoppers, whose pattern usually matches the particular lichen-covered rocks where they are found. Here's one.

The next morning we followed highway 14 on up into Searcy County and turned off at Spring Creek Road, and dropped on down the hill to the Buffalo River. This is another of our favorite places. Canoes put in here for float trips, and head off to the right towards Buffalo Point. We go down to the beach, and walk to the left along low dunes of flour-fine sand overgrown with willows. It's a good place for a variety of robber flies, but the two stars are Proctacanthus rufus and Proctacanthus hinei. These are large powerful robbers, and both largely red in color. They are very similar to each other, but P. rufus has a long and rather slender abdomen, and P. hinei has a long and double-thick abdomen. Normally they are found in two separate habitats, but in this one place they occur together, and in large numbers. The one thing that brings them together here is the especially fine powdery sand, in which both species deposit their eggs. Here is the pattern which we have pieced together in previous visits: In the morning the female P. rufus (we haven't seen P. hinei doing this) hunt along the river side of the piled up fine sand, searching in among the willows for horse flies and other large insects. Then, in mid morning, about 10:30, they start to move inland onto the small dunes to lay their eggs. The females have sharp-pointed digging tools at the tip of their abdomen, but instead of using them, it looks like they simply jam their abdomen deep into the very soft sand, and there they deposit their eggs.

The other side of the pattern is, at about 10:30 the males come flying in and set up territories along the softer fluffier patches of sand, waiting to waylay the females. By a little after noon they will all have vanished for the day.

We arrived after ten and walked along the beach side of the dunes. After we had gone a little way, I chased up a large insect carrying another large insect. It landed at a distance from me, and I looked with my binoculars and saw it was a female P. rufus carrying a large red paper wasp. When I approached more closely and looked again, I saw black marks on the thorax of the otherwise red wasp, which I believe made the species Polistes perplexus. The robber fly was very shy and kept flying away from me, but I finally got close enough for a distant shot which I have blown-up a bit to show you here.

By now we had gone as far up the beach as the dunes went, so we turned around, and followed back a path that was on the inside of the dunes. It was now after eleven, and the first of the males were arriving, and I took a picture of a big male P. hinei sitting on his territory. The females are shy and difficult to approach, and so are the males generally, but once a male gets on a good territory, it seems like nothing will make him move.

By this time the heat (it was 99) and the effort of slogging through the soft sand, had worn us down so much we got back to our car with relief, turned on the air-conditioner, had numerous drinks, and headed back to Jonesboro.

No comments:

Post a Comment