Appearance
Females have a body length of about 9 mm; males are slightly smaller. Its legs are about 5 or 6 times the length of its body. Its habit of living on the ceilings of rooms, caves, garages or cellars gives rise to one of its common names. They are considered beneficial in some parts of the world because they kill and eat other spiders, including species that can be considered a problem to humans such as hobo and redback spiders.
Naming
This is the only spider species described by the Swiss entomologist Johann Kaspar Füssli, who first recorded it for science in 1775. Confusion often arises over its common name, because "daddy long-legs" is also applied to two other distantly related arthropods: firstly another arachnid from order Opiliones otherwise known as the harvestman, and an insect less ambiguously called the crane fly.
Behavior
''Pholcus phalangioides'' is not considered aggressive, its first line of defense being to shake its web violently when disturbed as a mechanism against predators. It can easily catch and eat other spiders , mosquitoes and other insects, and woodlice. When food is scarce, it will prey on its own kind. Rough handling will cause some of its legs to become detached.Peak breeding in this species occurs between June and September. The female holds the eggs in her pedipalps. Spiderlings are transparent with short legs, and change their skin about 5 or 6 times as they mature.
Habitat
Originally a species restricted to warmer parts of the west Palearctic,better source needed through the help of humans this synanthrope now occurs throughout a large part of the world. It is unable to survive in cold weather, and consequently it is restricted to houses in some parts of its range.
Defense
An urban legend states that Pholcidae are the most venomous spiders in the world but that it is nevertheless harmless to humans because its fangs cannot penetrate human skin. Both of these claims have been proven untrue. Recent research has shown that pholcid venom has a relatively weak effect on insects. In the ''MythBusters'' episode "Daddy Long-Legs" it was shown that the spider's fangs could penetrate human skin , but that only a very mild burning feeling was felt for a few seconds.References:
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