Delta Journal
by Bob Thomas

Crown Spiders, Gasteracantha cancriformis, are very common in Louisiana swamp forests during the spring and summer. Some locals call them “crab spiders” because their backs remind one of a blue crab shell - oval, shiny, and with many spikes extending around the edges. This carapace (the back) also looks like a king’s crown, and there is a whole family of spiders that are officially called crab spiders (Family Thomisidae), so we’ll call them crown spiders (they belong to the Family Araneidae).

These little fellows are only about three quarters of an inch wide, and the tops of their carapaces may be any one of three colors: yellow (yeller yeller), orange-red (ernge ernge), or white. There seems to be no reason for the color, and we often find all three on a walk in the woods, though sometimes we find just one. The colors are such that they look like they have been painted with enamel, with the base color of the spider being black.

The delicate webs are also very characteristic. They daily create a flat orb, meaning that the webs are circular with radiating lines with circular threads uniting them (what we might call a typical spider web). The webs are always constructed in a shady, open place, and the orb always slants at a slight angle to the ground. The spiders sit in the middle of the web, with their backs hanging in the direction of the slant. When frightened, they fall toward the ground, breaking their relatively fast fall into the foliage by a silken line from their spinnerets.

Though all of this is characteristic, the most noticeable feature of the web is that the support lines that are attached to twigs and limbs have “dashes” along their lengths. That is, they have little sections about 3/4 of an inch long that have thickened webbing, so that from a distance the lines appear to have an occasional “dash” linked to the others by a thin line of webbing. Sometimes when the web is gone (either the spiders cut it down, or a bird flew through it), one will see a single dashed line between two points. This is enough to know that a Crowned Spider once was there.