TALES FROM THE BUSH
In the bleak midwinter
Two male moths turn up the heat on a cold winter’s night
“HAVING RECEIVED A CALL TO ‘Dad’s Taxi’ and chauffeured my daughter to cricket practice, I had an hour of Norfolk’s wintry night to kill before pick-up. Pub or walk? Given that male winter moths had blizzarded through our car headlights, I plumped for woodland wander over pale ale.
Winter moth is a well-studied insect, famous among ecologists. Perhaps I could find a female – it attracts males by crawling up trees and issuing sex-scent pheromones. Might I even spot a copulating pair?
Upon arrival, I delighted in trees ribboned with about 1,500 male winter moths. Thrillingly, searching trunks revealed 20 mating pairs, their ‘sexy bits’ clasped firmly together. Then I stopped short, unable to believe my eyes: here were two male moths with their nether regions conjoined, apparently copulating!
Gobsmacked, I grabbed photos as evidence. Then, forced to prioritise parental duty over scientific investigation, I departed daughter-wards.
My ever-widening circle of naturalists and moth boffins were bewildered. I pored over scientific literature and it transpired that while what evolutionary biologists term ‘same-sex sexual behaviour’ (SSSB, for short) had been documented in 10 moths, it proved unknown within the winter moth’s family, Geometridae. Moreover, it had never been found among moths in the UK. Most remarkably, SSSB had only been recorded among laboratory moths, never wild ones. My chance observation, in a random British wood, was seemingly nothing less than a world first.
Scientists propose various evolutionary theories to explain SSSB among insects, including helping social cohesion and practising mating skills. For these winter moths, the most plausible explanation seemed to be mistaken identity – one male perhaps being caked in female pheromones from an earlier mating.
Alternatively, might boys just wanna have fun? If SSSB has remained unobserved in perhaps the world’s best-known moth species until now, maybe we should be open-minded about alternative explanations of unexpected behaviour.
Whatever the uncertainties, one conclusion was clear. I was now up for every taxi-run going.
Have a wild tale to tell? Email a brief synopsis to catherine.smalley@ourmedia.co.uk
ABOUT THE AUTHOR
James Lowen is the author of Much Ado About Mothing (Bloomsbury, £18.99) and British Moths: A Gateway Guide (Bloomsbury, £16.99). You can find out more at jameslowen.com.