Synchronous fireflies illuminate the forests of Great Smoky Mountains National Park, Tennessee, USA

© Floris van Breugel/Minden Picture

By the light of the fireflies

Every year between late May and mid-June, synchronous fireflies gather into a sparkling, rhythmic lightshow in the forests of Great Smoky Mountains National Park, in the US states of North Carolina and Tennessee. As part of their two-week mating display, the females synchronise their flashes with nearby males so that every few seconds waves of light ripple through the woods. Each species of firefly has a characteristic flash pattern that helps the males and females recognise each other. In most species, like this one, the males fly and flash, while the females generally stay still and respond with a flash of their own.

It's not clear why some species of fireflies flash in time with each other, although some think it is to do with diet, social interaction and altitude. No matter why they do it, the flashing of fireflies is a magical sight - and we can all use a little magic sometimes.