Saturday, August 8, 2009

A few facts about daddy longlegs

Phalangium opilio, the daddy longlegs or harvestman, is neither a spider nor an insect, but rather a relative of spiders. They've been around, more or less unchanged, for over 400 million years, according to the very interesting article about them on Wikipedia, and they're all over my garden these days, most commonly seen by me sunning themselves on leaves or the outside walls of my house. Daddy longlegs is nocturnal, so very likely it is mostly resting and digesting whatever it ate during the night, which, my sources say, is small insects, dead insects, decaying vegetable and fecal matter, and so on. I've personally seen one attempt to drag off a piece of a dead and dried-up earthworm, only to be easily chased away from its prize by a few ants.

Like spiders, the daddy longlegs has four pairs of legs, the longest legs per body length of any creature on the planet. The second pair is equipped with special sensors and is used like antennae. This one has seen some action, and is missing a few:


They live for one year, and only their eggs, laid in the soil in fall, overwinter.

The two eyes are raised on "turrets" in middle of the cephalothorax:

Unlike spiders, daddy longlegs can eat food particles, not just slurp up liquid. The leglike pedipalps are used to draw food into the mouthparts, and the jaws, or chelicerae, can be used as pincers, like a crab's, though they are not fanged. The daddy longlegs has no poison glands.

Instead, it has defensive stink glands above the joints of the first pair of legs, which emit an unpleasant odour when the creature is disturbed (click for a clearer view):

They seem to like to come into the house, and will often find their way through the living room, down the stairs, and into the basement, where there is not much for them to eat or drink (they do drink, and I rescued one from the side of my hot water tank, which for a few days had a slow leak from a worn-out washer). Without my help, though, unless they can find their way back upstairs and out, they're an easy prey for the basement spiders:

Which must be a terrifying and gruesome end...

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