ZOO-ology column: Daddy-longlegs mistaken for spiders, insects
By Judie Farnsworth
May 13, 2012 at 12:13 a.m.
Updated May 14, 2012 at 12:14 a.m.
Will the real daddy-longlegs please step forward?
Thought you knew a daddy-longlegs when you saw one? Maybe not.
Did you know there are two creatures we call daddy-longlegs? And - the real deal isn't a spider.
Like spiders, they are part of the class arachnida, but they have their very own order - Opilion. They're also known as harvestmen or opilinoids and are usually confused with what we call cellar spiders, pholcidae, and crane flies, insects.
In simplest observations, arachnids have eight legs, no wings and no antennae. Crane flies, being insects, have six legs.
Spiders have two visible basic body segments and usually six to eight eyes.
Harvestmen, or daddy-longlegs, appear as one body segment and have two eyes.
Unless you're moving logs or rocks - the most common places to find harvestmen - you may not be seeing many of these creatures. But what are all those long-legged guys you frequently see?
Folks refer to them as daddy-longlegs without realizing there's another choice.
Take a close look at their bodies. If they're segmented, they're pholcidae, or cellar spiders. Actually, with cellars being a rarity in these parts, garage spider may seem a more fitting title.
At any rate, it's become acceptable to refer to pholcidae as daddy-longleg spiders as opposed to just daddy-longlegs, the title for the real deal.
Harvestmen neither have spinnerets nor produce silk. If they're in a web - they're most likely the dinner. They eat all sorts of insects, earthworms, decaying plant matter and are very fond of aphids. Following dinner, they floss by pulling their legs one by one through their jaws. As they grow larger, they molt. After their outgrown body skin, or casing, splits, they then draw each long leg out of its worn casing.
Myths seem to persist, but daddy-longlegs are harmless to people because they don't have poison glands. But if threatened, they may give off a stinky smell through scent glands.
When handled or caught, they can shed a leg which twitches, much like the familiar, green lizards known as anoles. This puts a daddy-longlegs at a disadvantage since legs are also used as sensory receptors. In addition, there doesn't appear to be any recorded incidents of cellar spiders being venomous to or biting people.
A few more facts:
More than 100 opiliones species live in North America, and 6,500 have been discovered to date, worldwide.
Fossil evidence indicates their existence 400 million years ago.
The name "harvestmen" may be from observations that they are more visible during times of harvest.
They may gather in large clusters by hooking their legs together.
Oh - and mommy's are called daddy's too.
Judie Farnsworth is a longtime volunteer at the Texas Zoo specializing in educational programs.