Monday, January 24, 2011

glow-worms aren't worms

They are the larvae (maggots) of a fly that has a very unusual lifestyle. Glow-worms inhabit a wide variety of terrain but seem to favour protruding rock ledges like those at Easy Street Retreat and caves.

When night falls, they lure insects into elaborate snares using a green/blue bioluminescence. The snares are made up of a mucus tube, in which the glow-worm resides; bracing threads, which suspend the glow-worm from its substrate; and 'fishing lines', which hang vertically beneath the mucus tube. Fishing lines can reach up to 40cm in length if undisturbed, and are studded with globular secretions of mucus to immobilise the insects such as midges and flies that blunder into them. When an insect is caught, the glow-worm reels its catch upwards using its mouth parts, and attaches it to the mucus tube to prevent escape.

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