Friday, 18 July 2014

New Nocturnal Neighbours

This evening marked the last night of the marine mammal field course. Instead of crawling out for that last social, I wanted my bed; however, as I made my way home I got that "Farland-Point-Feeling". So my headphones and I took the long route home, I make a couple of loops, music blaring, before something catches my eye. There is a green LED shining from the grass beside the path. Someone's dropped their phone... or a camera. I reach down and contact nothing but grass; I try again. 

This was about when the penny dropped and I reached for my own phone for a little extra light. "Please let it be a glow worm...." Sure enough, more light revealed the outline of this unassuming little beetle with her luminous bum. A brand new beastie for me, and thoroughly worth missing out on a hangover for. 

Lampyris noctiluca

Glow worms are most commonly found in southern England and lowland Scotland and Wales, and are active from May to late August; with peak "glowing" period in June/July, between 2200 and 2300. Its not just the females that glow; larvae and even eggs can emit a week light. 

They life cycle begins as one of 50-500 small cream eggs, which hatch into larvae that survive on a diet dominated by slugs and snails. This larval stage looks like a large ladybird larvae with cream dots, and can last up to 3 years, after which they pupate into the rather drab - winged - male form, or plated -glowing - females (above). These adult stages have no functioning mouth-parts and are relatively short lived.

The light of the glow worm comes from a mix of luciferin and the enzyme luciferase, and is used in attracting males, which have exceptionally sensitive eyes. As a result, one of the threats to glow worms is light pollution - other culprits being habitat loss and pesticide use. Although previously seen in large numbers on Cumbrae, this single sighting a lucky chance encounter; despite this, these LED beatles are well worth keeping your eyes open for, just in case.

After sending my sighting to the UK Glow Worm Survey, Richard sent me back a link to a great paper on Farlland Point glow worms by Millport Marine Station superintendent Richard Elmhirst, written in 1912. It can found here.

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