 INTRODUCTION: The Portia
group of spiders contains 15 species of African, Asian and Australian
jumping spiders measuring up to 10 millimetres or 0.39 inches. Odd in
appearance, it resembles a scrap of vegetation. Rather than scurrying
about like other jumping spiders, the Portia has slow, choppy gait, much
like robots in science fiction movies. The Portia is one of nature's
most versatile predators.
HABITAT: Unlike most other
spiders which spin webs and settles within its own environment, the
Portia is a creature whose predatory reputation is legendary. It is very
intelligent and makes its home in his prey webs. With its ability to
mimic and detour with deception to capture the resident spider. In many
cases where a spider can sense a Portia, they panic and abandon their
webs. Basically, where web building spiders are found is generally where the
Portia Spider can be found. They prefer leafy areas in warm climates. This
spider also does a lot of walking. They can spin silk shelters or nests
which are usually densely woven in a tubular shape.
PREY:
The Portia Spider prefers other spiders to insects. One if the Portia's
specialities is invading another spider's web and eating the spider. It
stands on another spider's web and plucks at the silken threads, imitation
the vibrations made by mosquitoes. They will also eat spider egg sacs. It
pounces on its victim after hours of stalking and injects a broad spectrum
venom capable of killing virtually any insect and spider. With the ability
to trick just about any kind of web building spider, it can capture spiders
from one tenth to twice its size.
BREEDING: The male spider
shows off to the female by stiffly extending and shaking its fore legs. The
female then drums and tugs the web. The breeding can take place in or out of
the web. When the male comes closer, the female may however, not mate but
lunges out and kills him. In other cases, she will mate first and then kill
him. Some types of female Portia Spiders lets the male mount her and ten she
drops on a dragline with the male onboard, where she may swing around and
eat him. The Portia uses trickery to capture even their own species to mate.
The eggs can be some potential food for a rival. Another female Portia is
more likely to be the predator because cannibalism is so frequent with the
Portia.
VENOM: The venom is only
lethal to insects. Humans will not be affected if bitten. The size of these
spiders indicates that humans will not receive a nasty bite if bitten.
INTERESTING FACTS:
Portia Spiders mimic or copy the habit of other
spiders. They have been reported to be very smart little spiders with
amazing abilities. The Portia has eight eyes, a large pair up the front
which gives them excellent vision and the ability to see colour, three
smaller, less obvious pairs in rows from front to back along the top of its
head, allowing them to sense light and motion. These spiders are notes for
being one of nature's most efficient serial killers and are no bigger than a
small button.
BIBLIOGRAPHY:
1. Jackson, R.R Cues for web invasion and aggressive mimicry signalling in
Portia, Journal of Zoology, London 236:131-149
2. Jackson, R.R and S.D Pollard, 1996 Predatory behaviour of jumping
spiders, annual review of entomology.
3. Jackson, R.R and R.S Wilcox, 1994, Spider flexibilty.
4.
http://www.sigmaxi.org/amsci/articles/98articles/jackson.html
5. Photo: Portia fimbriata - Wikimedia.org
Information
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