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Cheiracanthium (long-legged sac
spiders) Life
> Eukaryotes
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Opisthokonta >
Metazoa
(animals) > Bilateria > Ecdysozoa > Panarthropoda > Tritocerebra >
Arthropoda > Arachnomorpha > Cheliceriformes > Chelicerata > Euchelicerata
> Arachnida > Araneae
> Araneomorpha > Family: Miturgidae
Derived from the Greek "cheiro" meaning "hand" and "akanta"
meaning "spine" relating to the male palp.
Cheiracanthium spiders range from 3-12.15 mm in body
length and make silk sac retreats, hence the common name of sac spider. They are
creamy straw coloured but sometimes the carapace and legs might be slightly
darker than the abdomen. The abdomen may present with an indistinct dorsolateral
folium mark. Cheiracanthium has a black face and chelicerae and the first
pair of legs is noticeably longer than the fourth pair and these they use for
detecting and capturing their prey
Clubiona resemble Cheiracanthium but have the first pair of legs
similar in size to the fourth and if the chelicerae is darker than the carapace
it will vary from brown to maroon in colour. Clubiona does not enter
buildings.
Long-legged sac spiders are fast and aggressive, free
ranging and nocturnal and commonly occur on vegetation. They are important in
controlling agricultural insect pests. I have, on more than one occasion found a
sac spider gazing up at me from a bunch of grapes in the local supermarket.
They construct a silk-like retreat in a curled leaf or in
the heads of
Protea flowers. With the onset of summer they find houses an ideal
habitat, constructing their sac retreats in the folds of curtains, bedding,
clothing, doorframes and corners. Being active at night, it is then that most
bites occur when the animal is inadvertently pressed against the body, as the
large fangs of this spider are capable of penetrating light fabrics.
Absent only from the polar regions there are 8 species in
South Africa with Cheiracanthium furculatum (previously Cheiracanthium
lawrencei) responsible for about 70-90% of all spider bites in South Africa.
The bites, although not life-threatening, are nasty as the venom of these
spiders is cytotoxic.
Text by Norman Larsen © |
