Page 22 - The Miracle in the Spider

22 THE MIRACLE IN THE SPIDER

The Lassoo-throwing Spider
Of all the many species of spider, one of the most interesting, because
of its hunting techniques, is the "Bolas" spider. Dr. Gertsch, an expert on
spiders, has established as a result of his detailed research on this creature,
that it uses a noose to catch its prey.

Bolas spiders hunt their prey in two stages. In the first stage the spider
spins a thread with a sticky end and lies in ambush. Later it will use this
sticky thread as a lassoo. Then, in order to attract its prey to it, the spider
gives off a very special chemical. This is a "pheromone," which female
moths use to attract males for mating. The male moth, deceived by the
counterfeit call, approaches the source of the smell. The spiders have very
poor eyesight, but can make out the vibrations set up by the moth as it flies.
In this way the spider can feel its prey approaching it. Now the interesting
thing is that, despite the fact that the Bolas spider is almost blind, it can
catch a flying, living creature with a thread it makes itself hanging in the air.
The book, Strange Things Animals Do, likens the spiders' hunting
technique to a cowboy throwing a lassoo:
The spider spins a silky cord, then puts a weight on one end — a heavy bit of
gum. In this way, the weapon reminds one of a cowboy's lassoo. Then it takes
the cord up in its two front legs, which now act like arms. When a moth flies
by, it throws the lassoo. The sticky, weighted end hits the body of the flying
insect and sticks to it. The moth is then roped in and the Bolas spider wraps it
up. 4
The second stage begins when the victim, deceived by the smell,
approaches. Drawing its legs back the spider gets into the attack position
and throws the lassoo faster than the human eye can see. The moth is
caught by the sticky ball at the end of the thread. The spider reels its prey

in and bites it, paralysing it. Next it wraps the moth up in a special thread,
which keeps the food fresh for a long time. In this way the spider preserves
its food for later consumption.
In the same book the writer evaluates the spiders' planned movements
in these terms: