Current Issue

Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Who's that spider in my bed? - Fishing spiders, Wolf spiders, Cellar spiders, and Harvestmen

 

Lurking on a pillow, this fishing spider measured almost 3 inches from claw to claw.

 

Cool evenings, Halloween just around the corner, and scary creatures about. This week several creepy arthropods appeared in our homes in unlikely places to raise our hair and give us the willies. Our first spooky guest, a rather large fishing spider, was discovered by one of our research assistants, Zach, ensconced on his pillow when he awoke one morning. Fishing spiders, such as the brownish-gray fishing spider, Dolomedes tenebrosus, are often found near or in water but they also hunt in forests and, apparently, on Zach's pillow. Fishing spiders do not build webs to capture prey. They roam freely and consume a variety of animals in and on water and on land. They can run across the surface of a pool or stream and actually dive and remain submerged for several minutes where they hunt and capture small fish and tadpoles with sharp claws and powerful fangs. Fishing spiders belong to a clan known as nursery web spiders, so called for their habit of building a small web to serve as the hatching place for tiny spiderlings that emerge from an egg sac. Although the brown fishing spider is probably able to deliver a memorable bite, our pet was quite docile and posed politely for photographs.

Notice the tiny spiderlings riding on the back of their mother, a rapid wolf spider.

A second close encounter of an arachnid kind came with the discovery of a female rabid wolf spider,Lycosa rabidaThis was a special treat because the proud mother was carrying more than two-dozen spiderlings on her abdomen. The female spins a round eggs sac and drags it about until her babies hatch. The tiny spiders clamber on their mother's body and hitch a ride until they are large enough to fend for themselves. Wolf spiders are among the most common hunting spiders found in our gardens. They are important predators of plant pests such as leafhoppers, lacebugs, and caterpillars. Most wolf spiders do not make webs but hunt on the ground. Some build burrows in the ground as a refuge to hide and ambush prey. Although they look fierce, rabid wolf spiders are believed to be harmless to people. However, a close relative of the rabid wolf spider known as the European Tarantula, Lycosa tarentula, was once the most feared of spiders in Italy. Legend has it that effects of the bite from the European Tarantula could only be cured by performing a frenzied, whirling dance called the tarantella. Sounds like fun.

This delicate cellar spider is really quite vicious to other small insects and spiders but harmless to us. 

The next stop in my little shop of eight legged horrors was a downstairs bedroom where I encountered a collection of cellar spiders. These delicate spiders construct loose irregular webs along baseboards, windowsills, and in corners of the floor and ceiling. They are often detected by a scattering of buggy bodies on windowsills or carpets beneath webs. Favored meals include small flies, beetles, moths, other spiders, and in my basement, pill bugs by the dozens. They have remarkably long, slender, legs and are said to shake their webs vigorously when hunting or disturbed. They are not known to bite humans.

Daddy long-legs, a.k.a. harvestman, does it have the most venomous bite of all eight-leggers?

Perhaps the spookiest of all of our eight legged invaders is the harvestman also called “daddy-long-legs”. These arachnids are not true spiders but belong to another group called the opilionids. When not climbing on the back of my sofa, they are usually found outdoors in leaf litter or on vegetation where they pick on slow moving prey such as earthworms, caterpillars, moth pupae, and snails. Some feed on bird droppings and decaying vegetable matter. Instead of eight eyes, harvestmen have two. They are protected from predators by stink glands that line the sides of their body and give off a nauseating odor when they are attacked. One urban legend has it that harvestmen have the most toxic bite in the arthropod world. Is this legend fact or fiction? If you would like to find out, stop by bug of the week next week or visit: http://spiders.ucr.edu/daddylonglegs.html