It wasn’t until relatively recently that I learned that what I’ve always called daddy longlegs spiders others know as Harvestmen, and in fact they aren’t spiders at all, altho they are related to spiders in the same way as scorpions, ticks and centipedes. Physically while spiders’ bodies have a head part and an abdomen, a harvestman’s head is incorporated into the body and they only have two eyes vs a spider’s eight. They are also harmless, lacking venom glands.
Harvestmen may eat aphids, caterpillars, beetles, flies, small slugs, snails, earthworms, spiders, even other Harvestmen. Most of them also eat decaying plant and animal matter, bird droppings and fungi. Sounds like a useful little critter to have around! Apparently if you watch them after a meal, they draw their legs one at a time through their jaws to clean them.
If you try to handle a Harvestman one or more of its eight legs may fall off, a possible adaptation to help it escape from a predator (they will also release a strong odor as a defense against predators, which include birds). However, the legs don’t grow back and loss of legs can slow the Harvestman down. They are also important sensory organs, loaded with nerves and thousands of tiny sense organs inside the microscopic slits in the legs. They also serve as ears, nose, tongue and possibly even as supplementary ‘eyes.’ Every ten days or so a Harvestman will split open and shed its exoskeleton, taking about 20 minutes to drag its long legs from their old casings.
The things you learn as a photographer/blogger!
Text based on info from http://www.backyardnature.net