Female glowing brightly in dark grass Photo Matthew Rumbelow
Glowing female climbing on grass Photo: Peter Scott
Glow-worm lava Photo: Peter Scott
Glowing female attended by 3 males Photo: Peter Scott
Remarkably - 4 males in attendance! Photo: Peter Scott
We are very grateful to Linda Worrall, the Glow-worm recorder for Rutland Natural History Society for contributing this page.
Glow-worms, which used to be very common, are now recognised
as a declining species, but they are present in Fineshade Woods. Late June and July is the best time to see them.
Wingless adult females emit a bright green glow from their tails after dark, mainly in June and July, in an area with an open aspect. This light attracts flying males to mate. After egg laying, both adults die. They die after a fortnight even if not mated, as they have no mouthparts.
"Once seen, never forgotten.... it's a really bright neon green light"
Larvae live for two years, feeding on snails mainly at night, and lying dormant under shelter in winter. Shortly before they pupate for 10 to 15 days in their third summer, they wander in daylight seeking a suitable place to do so. Generations overlap as a survival strategy.
Threats to Glow-worms:
habitat destruction and deterioration;
fragmentation of colonies reducing genetic diversity;
artificial lighting luring males away from glowing females so eggs are not laid;
poisoning by insecticides and eating snails contaminated by chemicals;
loss of snails killed by pesticide or lost habitat;
frequent, close grass mowing and disturbance, especially during glowing months.
Natural predators are few, possibly due to their taste: hedgehogs eat them, and bats may catch flying males.
Glow-worms' special problems:
larvae travel only short distances;
males fly, but conserve energy in winds and rain by not doing so;
adult females conserve energy for egg production by being wingless and static.
large mosaics of “unimproved” grassland;
scrub and varied woodland supporting snails;
open spaces or edges to enable females to display;
winter sanctuaries such as holes among stones, bases of trees or inside dead plant stems.
Such places are now rare. Fineshade Wood is an important relic, which deserves to be monitored and managed in the Glow-worm's best interests.
First find your glow-worm!
Fortunately the glows of the adult female will attract you, as well as her own species. She climbs up and back down the same grass stalk on track verges and paths, which are also accessible for us to walk along at night.
Look in daylight for open areas off-track and wait for dark, or note how to re-locate such potential display areas at night.
Keep records of sightings with dates, numbers and locations.
The trouble is, you can go one night and see many; the next night there could be none, all having been mated just after you left!
They usually start glowing and climbing their stalk around 10.30pm on any date in June and July, and continue for about three hours, though they don’t have to.
Lights are extinguished shortly after mating. To find a male is unusual as they only have two small luminous spots, as does a larva. In wind or rain, females do not climb high but still shine, but males may not fly.
Don’t confuse a glow with raindrops sparkling. Use a torch sparingly or you will not be able to see the glow, but once seen never forgotten, it’s a really bright neon green. Then shine your torch to see if a male has landed, but don’t get too close and squash any!
I do hope you’re successful.
Report your sightings
A phone call or email to Linda would enable her to collect findings and pass them on to the relevant county recorder.
Glow-worm Recorder for Rutland Natural History Society
Recent Fineshade records
30th June 2014. During bat surveys, Forest Holidays' surveyors recorded eight glowing females alongside the tracks near Smith's Spinney, Cunnington's Spinney and Dumb Bob Spinney. These were all on the edge of their proposed development area but no observations were carried out within the area.
21st March 2015. One lava recorded by Brian Laney. Report here.
2nd July '15. One female glowing at the gate post of a house at Top Lodge.
4th July '15. Female glowing in the same location.
Also another female low down on the wall of Top Lodge itself (the FC offices)
10th July '16. A female glowing again in front of a house at Top Lodge. Not seen subsequently.
13th July '16. 3 females seen glowing at a site deeper into the wood.
18th July '16. 3 more females at different sites with 100m of the Visitor Centre
18th and 19th July '16. Female outside another house in the wood.
Larva found by Brian Laney in March 2105
9th June '17. 7 females seen! 3 along the verge of the track running SE from the visitor centre, 1 outside a house at Top Lodge, 3 in different parts of Westhay Wood.
23rd June '17. 9 females reported by Lea Arden at different locations.
July '17. More reports from Bob Bullock, John Isherwood and Barrie Galpin. 7 more individual glow-worms.
Location of 2017 sightings.
Click on map for larger version
This year's sightings
28th May. An early record - the first female of the year was outside a house at Top Lodge - picture, right.
15th June. Another glowing very close to the above site
19th June. Four females glowing close to the bridleway leading to King's Cliffe. All within 100m of Top Lodge itself.
24th June. 18 glowing around wood during BftBrink event
25th June. 3 new females on the road near Top Lodge
29th June. 5 new females in the road new Top Lodge
30th June. Total of 13 between Top Lodge and the Gruffalo
3rd July. 2 in gardens at Top Lodge
Total of 41 different females recorded so far.