Daddy-longlegs, vibrating or cellar spiders

These spiders have very long legs like the harvestman. Therefore, they are called Daddy-longlegs. The difference between the daddy-longlegs and the harvestman is that in harvestman the cephalothorax and the abdomen is almost fused together which looks like one structure whereas in daddy longleg spiders the cephalothorax and the abdomen are two distinct features connected by a visible narrow tube. Unlike these spiders, the harvestman does not make webs.

The members of the Pholcidae family live in houses and buildings. They make their untidy webs in the corner of a wall or a ceiling. They are also often found in the basement or the cellars, thus being referred to by another common name as the cellar spiders. When they are disturbed or when they are under a threat of attack, they start vibrating in their web violently to scare off and discourage their enemy. Therefore, they are also known by yet another common name of vibrating spiders. The male spider has large palps.

There are three genera of this family found in NW-Europe: Pholcus phalangioides (common), Holocnemus pluchei and Psilochorus simoni (rare).

It is said that the venom of this spider is one of the most poisonous. Since the fangs of these spiders are too small to penetrate the skin, it is not considered a dangerous spider. Many spiders use their venom to kill their prey but the poison of almost all of them is harmless to humans. In Europe only the water spider gives a harmful bite. The kiss (bite) of the black widow that lives in southern Europe should be avoided.

The daddy-longlegs have a quite simple structure. Therefore they are classified in between the six eyed and the eight eyed spiders. The internal structure of the female sexual organ is identical to that of the six eyed spiders. The mating ritual of these spiders is also similar to that of the six eyed spiders.

The spider can be easily recognized by a small mass of body and its extremely long legs. They have four pairs of legs. The first pair of legs is five and half times the length of its body. The legs do not have any prickles but have long stiff hairs. The knee segment is much darker than the rest of the legs. Their venomous fangs are very small, too small to penetrate the human skin and even while catching a prey they are not used. Two of the eight eyes are very small. At the place of the heart (at the top of the abdomen) there is a dark spot. The spider must, as all spiders do, renew its skin. 

The mating ritual is similar to the ritual of the six-eyed spiders (Haplogynae). The male spider can copulate when it is one year old. When ready to copulate, the male spider makes couple of silk threads, then places his genital area on the thread and starts rubbing along the thread which stimulate his sexual organs. This action produces secretion containing his sperms, which is drawn toward his poison fangs, which is sucked up by his palps. Now the male is ready for the mating and goes in search of a female. When he finds the female, he lets her know of his honorable intentions by vibrating his whole body on her web. As the female approaches, the male caresses her first pair of legs, which quickly wins her favor. He then inserts both of his palps in the female vulva. Often the copulation goes on for hours with varying attempts in which the male withdraws his palps, reloads it with sperms and inserts it back into the female vulva. If the mating goes undisturbed, then the male is not eaten up. He remains in her immediate vicinity until death overtakes.

While this is happening, its is not unusual to find another male spider waiting for his turn. The female lives for about 3 years. But the male lives only for a year, copulates and dies.

Contrary to most other spiders, daddy-longlegs breed the whole year. You might find spiders with eggs in your cellars in the middle of the winter. The spider originally came from the tropics and is only found inside houses. They are not accustomed to seasons.

The fertilized eggs are not spun in a cocoon but are held in a small net of silk. Because the spider is always on the move, it carries the silk net containing the eggs in between her jaws. Only 20 -30 eggs are fertilized. The eggs are hung in a web before the spiderlings could emerge from their eggs. The mother eats the spiderlings that have difficulty in getting out of their egg. Shortly after emerging from the egg, the young spider changes his skin. They are transparent and have short legs. Even after several changes of their skin, the spiderlings stay with their mother and she carries them in between her jaws. At the end when all the egg yolk is consumed and the small spiders have practiced catching tactics with their sisters and bothers, they eventually leave their mother and start for themselves.

Daddy-longlegs does not have many enemies. Many spiders probably die in a vacuum cleaner or are killed by their own kind..