Daddy long legs (Order Opiliones, Family Phalangiidae)
Burleson, Texas (14 May 2007)

Photography by Nancy T.

Within the large group of jointed animals with eight legs is an order known, today, as the Opiliones. These are the harvestmen, which are not spiders but which, from a distance, look like spiders. Except for having eight legs, however, a close examination reveals major differences.  They have no silk or venom glands, and--though with some minor exceptions--their mouth parts cannot pierce human skin.  Instead of two body parts they have one.  And instead of six or eight eyes, they have two. Unlike spiders, they excrete an odorous musk for defensive purposes.  They prey on other arthropods and scavenge dead vegetable matter.

Over 7,000 species of harvestmen have been indentified, and many more are expected to be identified in time.  Harvestmen are neglected, taxonomically, because they do not impact man directly, at least not in serious ways.  As one writer put it, they exhibit good habits (by not causing us harm). As a result, though common throughout their range, they are not on man's radar screens.  In Texas, 18 species have been identified. Only one of their 37 families worldwide (the Phalangiidae) contains the species we call daddy long legs.

The body of a harvestman is not divided into a separate head, abdomen, or thorax. Instead, one undivided body part provides all the organs that, for more complicated animals, several body parts are required to handle.  The harvestman's two eyes are positioned on the dorsal surface of the anterior third of the body, in a slight protuberance that positions the eyes so that they look sideways.

Masses of daddy long legs may congregate together at certain times of the year, possibly in connection with mating. When threatened, the mass of harvestmen sometimes rises and falls in huge waves, creating a visual effect that easily frightens anyone unfamiliar with these otherwise innocuous creatures.

It does not help the harvestman's reputation that a thoroughly incorrect urban legend has circulated for years that they are the most venomous arachnids on earth. That legend has it that, despite their hardy venom, they are harmless because their teeth cannot bite humans. In fact, they have no venom glands at all. The worst that they can do is taint the air with a sickly-sweet-noxious odor from their musk glands.

Many thanks to Nancy T. for these photos....