Pholcus phalangioides

Pholcus phalangioides is found throughout the world. It is a common cellar spider throughout the United States. (Emerton, 1902; Jackman, 1997)

Pholcus phalangiodes can be found in undisturbed, low light locations. Some places one might encounter this spider are in basements, under stones, under ledges, and in caves. People most often associate these spiders with living on ceilings and in corners in homes. They make their webs large, loose, and flat, but they can make them in irregular shapes to fit into surrounding objects. Their webs are normally oriented horizontally. Pholcus phalangioides hangs upside down on the web it makes. (Emerton, 1902; Foelix, 1982; Jackman, 1997; Uhl, November 1998)

Pholcus phalangioides is pale yellow-brown except for a large gray patch in the center of the cephalothorax. The body and legs are almost translucent. These spiders are covered with fine gray hairs. The head is a darker color around the eyes. A translucent line marks the dorsal vessel. There are eight eyes: two small eyes in front of the two triads of larger eyes.

Females are seven to eight millimeters in length and males are six millimeters.

Because of the translucent quality of this animal, using a microscope it is possible to see the moving blood cells in the legs and body of a living animal. (Jackman, 1997)

A mother P. phalangioides watches over her newly hatched young (prenymphs) for about nine days until the prenymphs shed their skins to become little spiders. The young spiders then leave the maternal web, and go look for a place to build their own webs. (Stüber, 1999)

In studies done by Gabriele Uhl at the University of Bonn, male P. phalangioides seemed to be attracted to and to mate with larger females more often than smaller females. This may increase reproductive success for males, because large females produce more eggs than smaller females. (Uhl, November 1998)

Before mating, a male spider deposits some sperm onto a little web, and then sucks it into a special cavity within his pedipalp. During mating, which can take several hours, the male deposits his sperm into the female's epigynum, which is an opening on the underside of her abdomen. Females can store the sperm in a special cavity at the beginning of the uterus, called the uterus externus, until it is time for her eggs to be fertilized. Timing of fertilization and laying depends on the availability of food. Because the sperm are stored for some period of time, it is possible for a female to mate again. If this occurs, the sperm from the two males mixes in the uterus externa. However, the sperm of the last male mated with has priority in fertilizing the eggs. This is because of a mechanism of sperm removal during mating. Males perform rhythmic movements of their intromittent organs during copulation, which results in extrusion of most of the sperm already in the uterus externa.

After a female lays her eggs, she wraps them in silk strands and carries the package in her chelicera (jaws), located on the underside of her body. (Emerton, 1902; Jackman, 1997; Stüber, 1999; Uhl, November 1998)

The only parental care female P. phalangioides offer their young is nine days of protection as the prenymphs finish developing into spiders. (Stüber, 1999)

Pholcus phalangioides can live up to about three years. (Stüber, 1999)

When P. phalangioides is not mating, it is a solitary creature that work on catching food in its web. (Uhl, November 1998)

Male spiders find a female spiders by tracking the pheromones she leaves. During mating, tactile communication is probably of some importance. (Jackman, 1997)

Pholcus phalangioides seems to prefer other spiders and small insects as prey. Also, males and females have both been known to engage in cannibalism. Females have been seen invading another spider's web, eating that spider, and using the foreign web to catch new prey for themselves. These spiders kill and digest their prey using venom. (Jackman, 1997; Stüber, 1999; Uhl, November 1998)

When the web of P. phalangioides is disturbed, the spider swings its body around rapidly with its legs attached firmly to its web. It swings fast enough that the spider becomes very hard to see. This may be a form of camouflage. (Emerton, 1902; Stüber, 1999)

Because their diet is primarily insects, these spiders play the important role of controlling the growth of insect populations. (Stüber, 1999)

Pholcus phalangioides helps control pest populations. (Uhl, November 1998)

These spiders often live inside houses, where humans do not normally want spiders and their webs. (Uhl, November 1998)

At this time Pholcus phalangioides are not endangered or threatened, so there is no conservation underway (ESA).

Because one of the common names for Pholcus phalangioides is daddylongleg spider, it is often confused with the Harvestmen daddylong legs, which are a separate species that is not even a true spider. Also, despite the urban myth that the daddylongleg spider is the most poisonous spider in the world, there is no proof for this statement. It is thought that this rumor may have been started because P. phalangioides kill and eat other spiders, including the Redback Spiders, whose venom can be fatal to humans. But to be able to kill the Redback spider, the P. phalangioides need only to have a quicker bite, not be more venomous (Crew, Haudon).