Even though they look like a spider, harvestmen (aka daddy longlegs) are of another arachnid order called Opiliones.
Yesterday, Uzzi and I were lounging, chewing cud, when Uzzi said, “What’s that?” There was a long-legged, spider-like thing crawling along his back. Uzzi twitched it off, and it went away. Last night, we looked it up on line. It was a harvestman. Some people, including our mom, call them daddy longlegs.
Harvestmen are often mistaken for spiders, but they’re not. Spiders and harvestmen are both arachnids, but harvestmen belong to their own order, Opiliones. Spiders have a clear division between their heads and abdomens, but harvestmen’s bodies are fused into a single oval- or egg-shaped unit. Spiders have silk glands for web-building, but harvestmen don’t. Also, spiders liquefy prey before eating it, but harvestmen can chew solid food.
There are more than 6,500 species of harvestmen worldwide. They’re found on every continent except Antarctica, and they’ve been around a very long time. Harvestman fossils found in the Rhynie Chert beds of Scotland are more than 400 million years old!
Harvestmen have a single set of eyes and eight spindly legs that are much, much longer than their bodies. They can’t see well, so they use their extra-long second set of legs as sensory organs to feel where they’re going. They also have scent glands in them that release nasty-smelling fluid when a harvestman is scared.
Harvestman legs detach very easily, so sometimes you’ll see one with missing legs. As long as it has at least one of its second pair of legs and enough of its other legs to get around on, it’ll be fine. A creepy thing: If a leg comes off, it twitches and jerks for awhile. Ew! Scientists think this is to attract the attention of predators, allowing the harvestman to scamper away. Another thing harvestmen do when confronted by something that scares them is to bob their bodies up and down as though they’re doing pushups.
Harvestmen like one another; they sometimes gather into large groups with their legs twined together. In some specie,s the male gathers eggs from multiple partners and then guards and cleans them until they hatch. Harvestmen feed on small insects, decayed animal matter, and the juices of fruits and vegetables.
In olden days, country people thought that if they picked up a harvestman, it would point in the direction their cattle were grazing or, if they lost something, in the direction they should look. They also thought that if they killed a harvestman, it would rain.
Some people think that the bite of a harvestman is fatal, but they’re wrong. In fact, harvestmen don’t have venom in their mouth parts, and they don’t bite. If you want to, you can let a harvestman walk on yoy—Uzzi says it tickles—but be careful not to damage its long, fragile legs.