FRIENDS OF EDGEWOOD NATURAL PRESERVE
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FRIENDS OF EDGEWOOD NATURAL PRESERVE
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ARTHROPODS AT EDGEWOOD ON NATIONAL PUBLIC LANDS DAY By Paul Heiple This is the fifth in a series of articles on Edgewood’s arthropods by Paul Heiple. All photos were taken at Edgewood by Alf Fengler.—ed. Last year on September 27, 2008, San Mateo Department of Parks participated for the first time in National Public Lands Day. At Edgewood County Park, this participation somehow translated into another day of weeding, targeting—what else—Yellow Star Thistle (or as we long-time weeders call it, YST) that had regrown after being mowed during the summer. So what, you ask, does this have to do with Arthropods—the insects, spiders, and crustaceans? Well, when first-time weeders join the weeding group, those of us who have been around for a while like to introduce the new people to the wonderful discoveries that can be made while weeding. This helps make the weeding less tedious and, at the same time, enhances everyone’s appreciation for the diversity of Edgewood’s flora and fauna. And while weeding on this particular day, we discovered many wonderful things having to do with Arthropods.
The first two items we found were sac-like structures that were the egg cases of two large garden spiders commonly found at Edgewood, Argiope aurantia and Argiope trifasciata. The egg case of A. aurantia, the black-and-yellow garden spider, is about one inch long, shaped like a tear drop, and brown in color; it can be found hidden in thick grasses and forbs, usually some distance from its spider’s web. The egg sac of A. trifasciata, the banded garden spider, is a bit smaller, being approximately three-quarters of an inch in size, with a flat-topped shape and a whitish color, and it, too, can be found hidden in the weeds some distance from the web of its spider. The young spiders of both species hatch inside these structures during the winter and emerge from them in the spring. Hundreds of these young spiders are then dispersed through the air before settling down to the business of starting the next generation. Our third discovery looked like a piece of one-inch-long brown styrofoam. A closer look showed that it had some structure, like a seam. It was the egg mass of the Chinese mantid or Tenodera aridifolia, more commonly known as praying mantid. The styrofoam-like material provides insulation for the eggs that are embedded in it, thus keeping the eggs dry and the temperature around them stabilized until they hatch. These insects have become established in Edgewood, thriving on the grasshoppers and other insects that are plentiful there. Interestingly, Edgewood’s praying mantids are not as large as they are in wetter climates (they are about three-quarters the size of the ones I saw in Pennsylvania). Our fourth and final discovery was composed of several spiny items on a central piece more than one inch long—as one end had the foot of an insect, it was clear this was part of an insect’s leg. Judging from the size of this leg, the insect it came from must have been large; and as the color was white, the only insect I could imagine it to have been was the potato bug, also known as the Jerusalem cricket or Stenopelmatus fuscus. This is a heavy-bodied insect that can grow up to two inches in length and is often found in the cool, dark places of people’s homes. Indeed, this big fellow probably came by his common name because he showed up with the potatoes stored in the root cellar, a common feature of older homes. But “in the wild,” the potato bug is not so easily found, being nocturnal and preferring to live underground. However, Edgewood weeders have been known to dig one up from time to time. The poor fellow that was originally attached to the leg we found most likely met a rodent during the night and became a meal.
So the next time you’re out weeding, at Edgewood or at home, take a little extra time to look around. You just might discover an Arthropod. |
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