the zig-zag lines match their leg positions, which lead some people to suggest
that this helps give the appearance of longer legs. Some spiders build a
single vertical line, yet others a patch of zig zags in the centre of the
web. No matter the design, the spider sits right smack in the middle. We
do not know the purpose of these lines, but some of the explanations put
These spiders get their name for the way their hold their eight legs
in pairs to form an X shape. The X is called the St. Andrew's cross
because it is believed that the saint was martyred on a cross of this
shape rather than the conventional + shape.
Besides their standard orb-web, Argiope spiders build additional white
opaque zig zag lines on their webs, called stabilimentum.
and wetland wildlife at
Sungei Buloh Nature Park
features: Small spiders with brightly coloured
abdomens; striped white, red, black and yellow.
Male: 2mm. The male lives
on the female's web.
Status in Singapore: Common
in mangroves. This species is only recorded from Singapore.
Like many other spiders,
the male is half to one-third the size of the females.
- They stabilise
the web (hence their name!)
- They warn larger
animals in the same way that safety strips on glass doors warn people
from walking into them. Thus the web is protected from damage by flying
- Research has shown
that the silk in the stabilimentum reflects ultraviolet well, unlike
the silk used in the rest of the web. Thus, the designs may mimic flowers,
which also reflect ultraviolet light well, and often have lines to guide
insects to honey like airport lights do for airplanes. Instead, the
insects are guided to the spider which sits in the centre!!
many other spiders, only the female Argiope mangal build the
webs. These are orbs 38-50mm wide and contain only 2 stabilimentum.
Argiope versicolor, which is found inland, makes the "full"
cross with 4 stabilimentum. When prey is caught in the web, the spider
throws out broad swathes of white silk to immobilise the prey, then
rapidly rotates it to tighten the binding before administering the
fatal bite. Small spiders which are unable to rotate the prey, run
around the prey instead as they throw out binding silk.
it is disturbed, Argiope mangal vibrates the web so its outline
becomes blurred. Another response to flip to the other side of the
web in a blink of the eye, through a gap in the web. Yet another response
is to simply drop off the web. Large ones may simple wiggle their
abdomens, which have a pair of large black eye-like dots.
rare look at
a moulting spider
Role in the habitat: like other predators,
the spiders keep the population of their prey in check. They in turn, are
eaten by other creatures in the food chain.
- Joseph K H Koh,
"Spiders of the Family Araneidae in Singapore Mangroves",
The Raffles Bulletin of Zoology, 1991 39(1) (p. 169-182).
- Joseph K H Koh,
"A Guide to Common Singapore Spiders", BP Guides, Science Centre,
1989 (p. 28-30 for other Argiope species: habits, habitat, distribution,
photos of spider and web).
- Peter K L Ng and
N Sivasothi, "A Guide to the Mangroves of Singapore II: Animal
Diversity", Singapore Science Centre, 1999 (p. 92 on Argiope
Mangal: description, habits, habitat, photos).
- Rod Preston-Mafham,
"The Book of Spiders", Chartwell Books, 1991 (95-97:
about their webs).