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When I was lived in New Zealand as a missionary I had the opportunity to visit the Wiapu caves and it was truly awesome to see the glowworms. They lit up the walls and ceiling of the cave as if they were stars in the night sky and it blew me away that such things can live where there is no light. The picture above is a great picture of how they look, but they don't look this way when you are in the cave because our eyes can't catch light as cameras can, but even so it is worth going to see them!
The type of glow worms found in the Waipu caves are the larvae of a fungus gnat and the picture above shows two of the fungus gnats as well as an empty husk of the pupa and some strands of silk from the larvae. The adults only live for a few weeks and they are there only for mating and laying eggs, as they cannot eat. The female lays over a hundred eggs, which hatch into the larvae in a few weeks after being laid. The picture below shows what the eggs look like.
The larvae are a few millimeters long when they hatch and grow to about three centimeters long. They are carnivores which catch their prey by using silk threads which hang down with sticky mucus droplets lining them. When prey gets trapped in the mucus the glowworm pulls the silk strand up and eats what ever got trapped in it. The picture below shows the silk strands with mucus droplets lining them.
Larvae shed their skins about four times and stay larvae for a few months to about a year depending on the availability of food. They are soft with a hard head and are very sensitive to wind, as they cannot hang their silk snares without them getting tangled if there is wind.
The larva get it's name: glowworm because it glows in the dark, a bright light blue color as in the first picture and the last one. They glow to attract their prey and this is done by certain chemicals mixing in their abdomen which releases the light. It is really amazing to me how animals are able to survive in places like caves and be so beautiful too.
Hope you enjoyed the post!