I saw a tweet at the weekend stating that it was high season for glow worms. So, I hear you ask, what about them? Exactly, I realised that I knew absolutely nothing about glow worms, so I decided to do a bit of research.
There are two species of glow worms in the UK, but one is very rare and restricted to only a couple of sites. The common glow worm, Lampyris Noctiluca, (in common with other glow worms) is a member of the beetle family, and is dark coloured with three pairs of legs at the head end of the body. The green bioluminescent light is emitted by the flightless lady glow worm as a way of attracting any male glow worms flying by and wearing their light-sensitive goggles. (Male and larvae are only faintly luminescent.) As is so often the case in the insect world, the female is larger than the male coming in at between 15 and 25 mm.
(As they say on the TV, now for the science bit, for those of you interested, the glow is caused by the oxidation of luciferin.)
Once the green light has worked its magic the female glow worm turns off her light, lays her eggs and dies. The larvae look like the female, but have small light coloured spots. They feed on small slugs and snails, hanging about under rocks and bark for a couple of years before the adult emerges which then has a lifespan of only 14 days (this is cut tragically short by the adults’ inability to eat).
Glow worms are mainly found in the south of England, and favour chalky or limestone areas. (I am therefore not surprised that I haven’t seen any in Daventry because a) this is the land of claggy clay and b) I have never looked for one and, until researching this article, did not know what one looked like.) Disused railway lines are apparently cool places for them to hang out, although they are often seen in gardens, June and July being the optimum months.
There is quite a lot of information out there for those of you interested in learning more about glow worms, the most useful that I found being:
http://www.galaxypix.com/glowworms/#About%20glow%20worms
http://www.kendall-bioresearch.co.uk/lamp.htm
http://www.uksafari.com/glowworms.htm
So, have you ever seen a glow worm?