The webs of trashline orbweavers are more conspicuous than the spiders themselves. The webs are small, circular orbs that the spider “decorates” with a line of debris: the dry husks of insects it has eaten plus other bits of detritus, wrapped loosely with silk into usually a straight line. The tiny, well-camouflaged spider typically rests in the center of her “trash line,” almost always at the hub of the web. With her legs tucked in, her upward-pointed abdomen blends in with the debris. The egg sacs are also positioned among the trash. Color and patterning of this species are cryptic: tans, grays, or browns, with some individuals with white, black, yellow, or rusty red.
Five species of Cyclosa occur in North America north of Mexico, but only Cyclosa conica and C. turbinata are found in Missouri. They can be separated by the latter’s being smaller and having two humps on the fore part of the top of the abdomen (the humps are sometimes described as looking like “shoulders”). These diagnostic humps can sometimes be indistinct.
Similar species: Featherlegged orbweavers (Uloborus glomosus) also make blobby lines in their orb webs, but in their case, the blobs are all egg cases, while the trashline orbweaver’s blobs are mostly insect carcasses. Looking at the spiders more closely, the abdomen of trashline orbweavers points upward at the hind end, while those of featherlegged spiders points downward. Also, the first pair of legs of featherlegged spiders are remarkably long.
Habitat and Conservation
The trashlines of these orbweavers almost certainly function as a form of camouflage, allowing the spider to evade their predators. It reminds us that spiders usually have a dual role in ecosystems: predators to small insects, but prey themselves to other animals.
At first glance, the trashlines of these spiders look bird droppings that have run down the web and then dried, making it look derelict and old. This would put these spiders into the same category as several types of butterflies and moths, whose caterpillars also resemble bird droppings. In each case, this camouflage tells potential predators: “Move along; nothing to see here.”