Family: Pholcidae (daddy long legs spiders)
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The Pholcidae, or daddy long legs spiders, is a large
family with a worldwide distribution. They are harmless to people as their jaws
are unable to penetrate human skin and the venom dose is also too minute. Spider
specialists are often asked if it is true that, of all the spiders, the pholcids
have the deadliest venom and the only reason there are no human fatalities is
because of the small size of the jaws. There is no documentation on this. The
venom is possibly neurotoxic, although a few reported bites indicate that it may
be mildly cytotoxic, and is deadly to the prey. The myth is possibly a
misidentification with Loxosceles (the violin spider the culprit). The
pholcids, as well as other spiders, should be encouraged in the home as they
control various insect pests such as mosquitoes, flies, fishmoths, ants and
moths.
The Familial and generic name is derived from the Greek
"pholkos" meaning "squint-eyed.
Other taxa commonly referred to as daddy long legs include:
Opiliones (harvestmen - also arachnids),
Tipulidae (craneflies) and
Gerridae (pond skaters - hemipteran bugs that run on the water). The genus
Loxosceles, as stated above, is often wrongly identified as a daddy long
legs.
Pholcids hang inverted in what appears to be a messy,
irregular, tangled web. These space-webs are constructed in dark recesses, in
caves, under rocks and loose bark, abandoned mammal burrows. Pholcus and
Smeringopus are synanthropic, occurring in undisturbed areas in buildings
and cellars, hence the other common name, cellar spiders. The web has no
adhesive properties but the irregular structure traps insects, making escape
difficult. The spider quickly envelops its prey with silk and then inflicts the
fatal bite. The prey may be eaten immediately or stored for later. When the
spider is threatened by a touch to the web or when too large a prey hits the
web, the spider becomes invisible by vibrating rapidly and becoming blurred.
This blurring may protect the spider from spider hunting wasps (Pompilidae).
When off their webs, pholcids walk with an unsteady, bobbing action.
Certain species of these seemingly benign spiders are
araneophagous and invade webs of other spiders and eat the host, the eggs or the
prey. In some cases the spider vibrates the web of other spiders, mimicking the
prey to lure the host of the web closer.
Pholcids are fragile spiders, the body being 2 to 10 mm in
length and the legs are up to 30 mm long. Pholcus and Smeringopus
have cylindrical abdomens and the eyes are arranged in 2 lateral groups of 3 and
2 smaller median contiguous (together) eyes. Artema and Spermaphora
has a small globose (round) abdomen and its eyes are arranged in 2 groups of 3
and no median eyes. Pholcids are grey to brown with banding or chevron markings.
Pholcids are often confused with the violin spider (Loxosceles,
family Sicariidae) but the latter does not
occur in a web, is much more robust and is very agile on all surfaces. The false
violin spider or leaf-litter spider (family Drymusidae) does occur in a web
similar to that of the pholcids and in fact closely resembles them but are not
often encountered.
The eggs of the pholcids have no protective sac but are
held together as an agglutinated (glued together) mass (similar to balloons held
together with a few strands of silk) and, as with the
Scytodidae, are carried by the female in
the chelicerae and are attached to the web while she feeds. The eggs hatch after
2 to 3 weeks and the spiderlings are either carried by the female for a few days
or hang from silk strands in the her web. They mature after 5 moults.
Genera indigenous to southern Africa
Artema
1 species in South Africa. |
|
Pholcus
3 species |
|
Quamtana
20 species |
|
Smeringopus
5 species |
|
Spermaphora
5 species |
|
TText by Norman Larsen ©. |