Spider builds giant decoy of itself# Animals - 动物园
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http://www.newscientist.com/blogs/shortsharpscience/2012/12/spi
Spider builds giant decoy of itself
(Image: Phil Torres)
Hanging out in the jungles of Peru can be a dangerous pastime for a spider -
how do you dodge predators while casting your web in the open? A newly
spied type of Cyclosa spider has come up with a solution - hide behind a
giant, fake version of yourself.
Naturalist Phil Torres describes how he spotted the spider bodyguard while
trekking near the Tambopata Research Center in Peru.
"From afar, it appears to be a medium-sized spider about an inch across,
possibly dead and dried out, hanging in the centre of a spider web along the
side of the trail," he says. "Step in even closer and things start to get
weird - that spider form you were looking at is actually made up of tiny
bits of leaf, debris and dead insects."
Upon closer examination, Torres spotted a tiny, 5-millimetre spider hiding
behind its doppelganger.
Cyclosa mulmeinensis is already known to build decoy objects on its web, but
these tend to look like blob-like prey pellets and egg sacs. The newly
described decoys look more like a spider, complete with eight dangly legs.
To build their body doubles, the spiders gather leaf fragments, plant parts,
prey remains, egg sacs and other handy detritus. Then they arrange the
debris along specialised silk strands called stabilimenta to create the
shape and legs.
The results of such decoys are counter-intuitive - surely it's like covering
yourself in a giant fake steak before parading in front of the local lion
pride? But although such decoys tend to attract predators to webs by making
them more conspicuous, they may draw away enough attacks from the spider
itself to make them worthwhile.
Torres says that some Cyclosa species have a higher survival rate against
potential predators, such as paper wasps, because the wasps attack the
highly visible debris in the web rather than the spider itself.
Torres hopes to collaborate with spider specialists to determine if the
arachnid's unique behaviour could indicate the discovery of a new species of
Cyclosa.
Spider builds giant decoy of itself
(Image: Phil Torres)
Hanging out in the jungles of Peru can be a dangerous pastime for a spider -
how do you dodge predators while casting your web in the open? A newly
spied type of Cyclosa spider has come up with a solution - hide behind a
giant, fake version of yourself.
Naturalist Phil Torres describes how he spotted the spider bodyguard while
trekking near the Tambopata Research Center in Peru.
"From afar, it appears to be a medium-sized spider about an inch across,
possibly dead and dried out, hanging in the centre of a spider web along the
side of the trail," he says. "Step in even closer and things start to get
weird - that spider form you were looking at is actually made up of tiny
bits of leaf, debris and dead insects."
Upon closer examination, Torres spotted a tiny, 5-millimetre spider hiding
behind its doppelganger.
Cyclosa mulmeinensis is already known to build decoy objects on its web, but
these tend to look like blob-like prey pellets and egg sacs. The newly
described decoys look more like a spider, complete with eight dangly legs.
To build their body doubles, the spiders gather leaf fragments, plant parts,
prey remains, egg sacs and other handy detritus. Then they arrange the
debris along specialised silk strands called stabilimenta to create the
shape and legs.
The results of such decoys are counter-intuitive - surely it's like covering
yourself in a giant fake steak before parading in front of the local lion
pride? But although such decoys tend to attract predators to webs by making
them more conspicuous, they may draw away enough attacks from the spider
itself to make them worthwhile.
Torres says that some Cyclosa species have a higher survival rate against
potential predators, such as paper wasps, because the wasps attack the
highly visible debris in the web rather than the spider itself.
Torres hopes to collaborate with spider specialists to determine if the
arachnid's unique behaviour could indicate the discovery of a new species of
Cyclosa.