Once it was possible to see glow-worms in many places in Holtspur; for instance on the verges of Heath Road and Holtspur Top Lane, as well as on what is now the nature reserve. There may still be some in the local hedgerows but light pollution makes them very difficult to spot. It was delightful to find that, when Holtspur Bank was designated as a local nature reserve, glow-worms were still there in relatively large numbers. Consequently the Friends organise a glow-worm hunt every year and this is always well attended.
The Latin name for glow-worm is Lampyris noctiluca (night light) and the first thing to be said about it is that it is not a worm, but a beetle, and that it is only the female that glows brightly. The male, larva and egg are also luminous but to a much lesser degree than the female. She is wingless and attracts the winged non-glowing male with the bioluminescent glow of the rearmost segments of her abdomen. Many females climb up grass stalks or the lower branches of shrubs when they are ready to glow. In June and July the males swarm on warm nights, seeking the flightless glowing females. She dies soon after laying her eggs and these hatch into larvae which feed by paralysing snails and then sucking out their bodily fluids. The larvae may take two or three years to mature and metamorphose into adult beetles. Glow-worms are small, the males being 11-12 mm long and the females 16-18 mm. They are widespread over most of the country in rough grass at the edges of woods, but are not common.
Over the years the Holtspur Bank glow-worm hunt numbers that have varied from a maximum of about 40 sightings (July 2000) to a minimum of around 10 in other years. This variation may be due to all sorts of factors from, unfavourable weather conditions, simply not being spotted, bad conditions for hatching of a particular brood to a general decline reported in other parts of the country. Hopefully, the last is not the case and the search for them in July, in their favourite places on the edge of hedgerows and scrub clearings, will continue.