Written by Lucy Brzoska
In July the shadowy halls of Collserola’s shallow, trickling streams are filled with a spooky, fluttering presence.Groups of dark insects flicker in the half-light, or perch on isolated vantage points.
These are the male Copper Demoiselles, staking a claim for a stretch of stream. Their wings are black, and their bodies darkly iridescent, tinged purple like blackberries.When impressing the females, they kink their abdomens, revealing a red under-tip.This has saddled the species with the Latin name Calopteryx haemorrhoidalis
The common name, though, is inspired by the rich coppery tones of the female.She signals from a distance with white spots on sepia-coloured wings.
When a male, from his prominent lookout post, sees a female enter his zone, he’s immediately in attendance, serenading her in semaphore.The hovering wings form a cross, a performance being repeated up and down the stream.
After a successful courtship, the female is whisked up to a twig.
Eggs are deposited in a tangle of pink roots at the water’s edge.