As a child I remember seeing my first picture of a glow-worm in a book. “Wow, a beetle with a light bulb in its bottom, that has to be worth seeing”. The inquisitive mind of a six-year-old naturalist in the making begins to ask further questions. Why does it have a light in its bottom? Does it help it see in the dark? If so, does it walk backwards?

    Well twenty years passed and I finally decided it was about time that I found myself a glow-worm. I recalled reading a letter that was written to British Wildlife magazine (Clements 2002); in it were detailed instructions on how to make an artificial lure to attract male glow-worms (Lampyris noctiluca). The lures are very simple to construct and consist of a 10mm diameter, green light emitting diode (wavelength 565 nanometres), a 1000-ohm, 0.25-watt resistor and a 9-volt PP3 battery. The longer lead of the LED is connected via the resistor to the positive terminal of the battery. The shorter lead of the LED is then connected to the negative terminal. All of the components are available from Rapid Electronics Ltd (tel 01206 751166). Using black acrylic paint I then painted the LED so that it resembled the light spots found on the underside of a female glow-worm. Don’t be daunted by all the talk of nanometres and watts. It is very simple. I constructed five of these lures and secured each to the top of a 30cm tall block of wood. These were then stood in five large plastic bowls. At this point may I add a note of caution: to avoid embarrassment when purchasing a shop's entire stock of 45cm diameter mixing bowls it may be wise not to try and explain what you plan to use them for!

    So on the evening of Monday June 16^th 2003 I placed my lures at five different locations in what appeared to be suitable glow-worm habitat. Each lure was left in position between 10pm and midnight. As I collected the lures at midnight it was somewhat disheartening to find not a single glow-worm, let alone the swarms suggested in the letter. It was not until the following Saturday that I felt sufficiently motivated to try again. This time I visited a wonderful little Suffolk Wildlife Trust reserve called Spouse’s Vale where there were rumoured to be glow-worms. I took only one lure in my pocket with the cunning plan of holding it in my hand. Just before the sun set I found a place to sit on the ground in an area that was open enough for the lure to be visible from some distance away. My plan was to leave the lure turned on until it was either too dark to see or there was a risk of injury to myself from the vast number of glow-worms falling from the sky! Full of hope and expectation I turned on the lure.

    It was a warm, still night, so still that the rabbits sharing the field with me seemed to be especially noisy eaters. Even a pipistrelle that was working the edge of the clearing was squeaking at a surprisingly loud volume. I looked down at my outstretched hand and stared into the green glare of the lure. No glow-worms. A loud crack of a twig emanated from the trees behind me. A badger? Whatever it was it was slowly heading my way. Thoughts of the “beast of Assington” that had supposedly been sighted in a nearby field crossed my mind. “Don’t be stupid, it’s a badger” I reassured myself. A nasal snort from the undergrowth put my mind at rest, as I was sure that pumas did not make such noises. My attention returned to the lure, still no sign of a glow-worm. At this point I couldn’t help but laugh at myself. “What am I doing? Most men of my age would spend their Saturday nights up the pub trying to attract the opposite sex. Here I am sitting alone in the middle of nowhere being eaten alive by midges while trying to attract a beetle with a green lantern! “Right, that’s it, I am going home” I thought to myself. I was about to move when an insect approached with a rattling whirr of wings. It briefly stopped above the lure with an undulating hover before its engine stalled about one foot above my hand, which it subsequently crash-landed on. I fumbled for the torch and before I could turn it on there were eight to ten male glow-worms in a stacking formation above the lure. I studied my first glow-worms under the light of the torch, three of them were crawling over the LED.

    After I had got over my initial excitement I searched the area for a glowing female. A short distance away I discovered one at the base of some short grass with three males trying to mate with her. To test the effectiveness of the lure I turned it on and placed it two feet away from the female. Within seconds all three males had left the female and were on the lure. Apart from proving the lures effectiveness it also illustrated there was a danger of interfering with the glow-worms mating behaviour. It is for this reason that I would not recommend leaving a lure unattended if you use this method to confirm the presence of glow-worms.

    That evening I went home very happy having finally seen my first glow-worms. After seeing the male glow-worms’ reaction to the lure I didn’t feel such an idiot. I may not have found an attractive member of the opposite sex at Spouse’s Vale but at least I could tell the difference between the latter and a green LED!

Acknowledgements

Many thanks to Dr Simone Bullion for persuading me to write this and for taking a photo of the lure.

Reference

Clements, D (2002). An artificial lure for Glow-worms. British Wildlife 14: p 74

Nick Oliver

© 2003   Suffolk Naturalists' Society