Sunday, July 23, 2006

glow worm

one thing i long to possess that i never have is...party lights.


they make me happy.

when i was younger i used to go swimming and play Sorry! every day at my best friend's house. we'd do pretty much the same thing each day, every day of the summer and it never seemed to get old. shamu the inflatable whale, her sister's poster of robert plant (!?), photos of swamishree, and her glow worm provided additional companions to our endless hours of adventure.

i've always wanted a glow worm too. it would appear i like things that glow.

Things that glow can only be seen at night...

Glow worms are the larvae of a large mosquito-like fly that have a very unusual lifestyle.
In order to survive glow worms build elabourate traps consisting of anywhere between 10 to 50 plus vertical hanging threads of silk studded with sticky droplets of mucous to catch small insects such as mosquitoes, midges, fruit-fly, gnats etc. that are attracted by the light produced by the glow worm.
The pendulous web strands are attached to a lattice-work of silk threads across the ceiling of their lair. In turn the threads support the suspended mucous tube in which the glow worm resides and travels, enabling the glow worm to be attracted to the vibration of trapped insects.

The blue/green glow of the larvae is the result of a reaction between body products and oxygen in the enlarged tips of the lavae's excretory tubes. The light is the result of a chemical reaction involving several components: luciferin ( a waste product ), luciferase ( the enzyme that acts upon luciferin ), adenosine triphosphate ( the energy molecule ), and oxygen.
All these combined make an electronically excited product capable of emitting a blue-green light.
To the average person's sight, up close the light appears more blue than green.
Spectrometer readings show the colour is actually in the green colour spectrum.

Direct moonlight affects viewing of glow worms in exposed area colonies .
Only the brightest glow worms in exposed colonies are visible on full moon nights.
Immature glow worms cannot generate sufficient bioluminescence to compete with bright moonlight and whilst they are in fact glowing they appear not to be.
Glow worms that have their fill of food can shut down the bioluminescent reaction and cease glowing.

The name glow worms is a mis-noma as they are lavae, not worms.
Early settlers from the British Isles probably applied the common name 'glow worm' as a substitute for the English glow worm Lampyris noctiluca (actually beetle lavae, so they got it wrong there also) .

In colonies that are exposed to outside weather conditions , it is not unusual to observe a variety of small spiders sharing areas where the glow worm builds it's web sometimes covering the whole glow worm web area and using the light produced by the glow worm to catch insects. This deprivation of their food source may be a contributing factor to migration as some do of necessity move around finding more favourable locations . Overpopulation of glow worms in the initial hatching areas of necessity causes migration otherwise they tend to eat each other.
Natural erosion of soil areas also causes migration to occur and the patterns of colonies here in the soft earth-bank colonies are constantly changing. The writer has observed a free-fall of glow worms from a height of 8 metres due to erosion in a soft earth bank. The glow worms that were not crushed by the fallen soil survived and re-located.

Approximately two to three weeks later adult flies emerge to re-commence the cycle.
Male flies tend to live longer than females and can live up to four days.
The flies have no mouth parts or means of feeding, they live only to mate and reproduce by laying eggs .
Near fully-developed female flies in their pupal casing have the ability to send a low-intensity glowing signal to male flies at the time of their impending emergence. As a consequence of their signalling it is not uncommon to observe male flies adjacent to the pupal casings of female flies waiting for them to emerge.

The entire life of the glow worm lavae is spent inside a suspended mucous tube with it's head facing the escape route into a crevice or safety haven in the rock or earth wall into which they move at remarkable speed when disturbed.
The mucous tube insulates and prevents the glow worm from dessication.
At night inside the tube it moves back and forth breaking through the tube to repair it's web or to feed on trapped insects.
During the day the glow worm hides inside it's safety haven of a crack or hole behind the web to avoid daylight predators.

1 comment:

evandebacle said...

You have combined two of the things that make me saddest: thinking about summers from when I was a kid and my own bioluminescence shortcomings. You totally harshed my buzz.