Glow worm

Dr. David Merritt of the University of Queensland (Australia) discovered daily biorhythms as a factor in the act of turning on and off 'lights' in glowing worms, living only in Australia and New Zealand.

In this worm, the special cells behind the tail are the light-producing parts that attract the prey, while the fibers containing the glue-like mucus are the trap for them to hunt.

Watching the glowing worms living in the wet rainforests through video tapes, Dr. Merritt realized that the insects only 'turned on' at night and 'turned off the lights' at dawn.

So, what is the biological rhythm of glowing worms living in caves and never seeing light? Merritt said the cave-dwelling worm, which has a light-off cycle, contrasts with the forest-dwelling species, meaning they glow during the day and turn off the light when the night covers the cave.

From this finding, the researcher thinks that the glowing worm in the forest and the glowing cave in the cave are two different species.