365 Urban Species. #329: Harvestman

[urbpan]

Urban species #329: Harvestman Leiobunum vittatum

It is astonishing, given how common and abundant these animals are, that so little is known about them, and worse, that they don't even have a good common name. "Daddy long-legs" is the name I grew up with, but in some places that common name refers to crane flies or cellar spiders (and their relatives). The scientific name for members of the harvestman order is "Opiliones," a word I don't even wish to learn to pronounce. Harvestmen are found in fields, yards, gardens, and parks, and alongside buildings. They are apparently omnivorous, hunting much smaller animals, and feeding on fungi and detritus. The well-circulated story that they possess powerful venom is grade A bunkum. Not only do they lack venom, they lack fangs altogether. While they have eight legs and look somewhat spidery, they differ from spiders in several important ways: no fangs, no venom, no silk glands. Their vision (which seems to be poor) and breathing apparatus are very different from those of spiders, and they also have all their body segments fused, instead of the two part arrangement that spiders have. Their long legs are their most obvious feature, thin stilts carrying an oval body around. Unlike insects, they have no antennae, so their second pair of legs--threadlike and longer than the others--acts as a set of feelers. Often a harvestman is found without all eight of its legs, as they sometimes break off when a predator attacks. Nerves in the jointed limbs cause them to twitch after breaking off, probably helping to distract the attacker. About 5000 species of opiliones have been named. Once again, my identification here is tentative: Leiobunum vittatum is a common North American species, with distinctive markings on its body. However, the European species L. rotundum looks very similar, and I see no reason why it shouldn't be in North America as well, especially in urban areas.