Link to Life in the undergrowth: 3- The silk spinner documentary
Documentary Description
This episode examines the spiders and others that produce silk.
Attenborough visits a cave in New Zealand that is inhabited by fungus
gnats, whose illuminated larvae sit atop glistening, beaded filaments to
lure their prey. The ability to spin silk developed early in the
invertebrates' history, being first used as an adhesive. The female
lacewing still applies it in this way, to suspend its eggs from plant
stems. Spiders first employed it as a sensitive trip line to detect
movement, and Attenborough illustrates this by encouraging a trapdoor
spider. The speed with which it appears causes the presenter to jump in
surprise. The webs spun by orb-weavers are complex and can comprise up
to 60 metres of silk and 3,000 separate attachments. A time-lapse
sequence reveals their intricate construction. The largest are made by
nephila and can be several metres across. The venomous redback spins
three-dimensionally, and fixes vertical lines that suspend its unlucky
meals in mid-air. Meanwhile, the bolas spider swings a length of silk
with a sticky blob on the end, with which to snare passing moths.
Argiope exemplifies the dangers of mating that are faced by some male
spiders: unless they are careful, they can be consumed by the females.
The courtship of the wolf spider, though less risky, is one of the more
elaborate. Its nesting habits are discussed, along with the eventual
birth of its young, which cling to their mother's back.
