Family: Lycosidae (wolf spiders)
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The Lycosidae or wolf spiders, as they are commonly called,
are often seen dashing from under the grass trying to escape the lawn mower or
doing freestyle in the pool. The family name and common name are derived from
the Greek word "lycosa" meaning "wolf" due to the spiders' hunting method of
ambushing and running down its prey. (The Tarantula is in fact a European
lycosid and the name is incorrectly used to describe the America Theraphosids.)
Research has shown that the Lycosidae are important in
agriculture, as they are efficient controlling agents of insect pests. They are
harmless to man.
Most of the genera of this family have abandoned a
web-bound existence and have adopted a free ranging lifestyle, much like the
Pisauridae. It is a large family of mainly diurnal (there are some species that
are nocturnal), terrestrial (ground living) spiders with a worldwide
distribution with 28 genera occurring in South Africa.
Being diurnal their eyesight is well developed as opposed
to nocturnal species where the other senses are more developed. Eyesight plays a
particularly important part in their mating activities that include waving of
the pedipalps and raising of the front legs as if following a dance routine
(much like the Salticidae).
Lycosids can easily be confused with Zoropsidae and
Ctenidae but the eye arrangement separates them. The eyes of the Lycosidae are
distinctive, occurring in three rows. The anterior row includes 4 small eyes in
almost a straight row. Just above this row are the two large posterior median
eyes and set further back on the carapace are the two intermediate posterior
lateral eyes. A further lycosid identification character is that the females can
often be seen carrying a white round egg case that is attached to the
spinnerets. When the eggs hatch, the young are carried on the mother's abdomen.
Lycosids are 3-30mm in length and are cryptically coloured
in shades of brown, grey to almost black, depending on the habitat. The carapace
usually has darker lateral bands and a lighter median band running
longitudinally and may extend onto the abdomen. The abdomen could also have
spots or chevron markings.
Lycosids occur in a wide range of habitats, from mountain
tops, beaches, deserts and forests. However, they are less common in the latter
and the Zorpsidae seem to have filled the forest niche more successfully.
Lycosids are often parasitised by wasps probably because
they are free roaming and do not enjoy the protection of a web. The wasps will
parasitise them in one of two ways. Depending on the wasp species, the spider
will either be stung and immobilized, stocked into a prepared nest, have an egg
laid on it and then sealed into the nest, there may be one or . The wasp larva
then hatches and consumes its live prey that eventually dies as the larva
pupates. Secondly, a female wasp will immobilize the spider and lay the egg
directly onto it. The spider continues living a normal life with the wasp larva
feeding on it until the spider becomes too weak and dies. This coincides with
the maturation of the wasp larva that then pupates later to emerge as the adult
wasp.
While it is relatively easy to recognise a member of the
Lycosidae family, identifying the genus is more difficult although this can
often be deduced from the habitat in which it occurs. For example, Pirata and
Wadicosa are semi-aquatic as are some Pardosa species. Pardosa often found in
lawns and often fall into swimming pools. The absence of scopulae (tufts of hair
on its feet) prevent it from climbing the smooth walls and it eventually drowns.
Zenonina and Evippa occur in sandy, semi-arid regions and Tricassa occurs on
sandy beaches. Anomalomma and Hippasa are web-bound and occur in funnel webs
similar to the Agelenidae. (The two families can be separated as the Agelenidae
females do not carry the egg case on the spinnerets neither do they carry their
young on their abdomens). Hippasa is a fairly large dark brown spider with 2
rows of white spots on its abdomen.
Anomalomma and Hippasa
Anomalomma and Hippasa are web-bound and
occur in funnel webs similar to the Agelenidae. (The two families can be
separated as the Agelenidae females do not carry the egg case on the spinnerets
neither do they carry their young on their abdomens). Hippasa is a fairly
large dark brown spider with 2 rows of white spots on its abdomen.
Geolycosa and Lycosa
Geolycosa and Lycosa are referred to as the burrowing wolf
spiders. The burrow can be a cork-like trap door or a raised collar constructed
with silk and bits of vegetation. Lycosa is large, pale brown with pale brown
chelicerae that turn a reddish colour when threatened.
Evippa and Zenonina
Evippa and Zenonina occur in sandy, semi-arid
regions.
Pardosa
The name is derived from the Greek "arctos" meaning "bear".
Pardosa often found in lawns and often fall into swimming pools. The
absence of scopulae (tufts of hair on its feet) prevent it from climbing the
smooth walls and it eventually drowns.
Pirata and Wadicosa
Tricassa
Tricassa occurs on sandy beaches from Namibia to the Cape
Peninsula. It is possible that females construct burrows.
Text by Norman Larsen ©. |