Species of the day: Peacock

By James Duncan

Learning and Engagement Officer

The Peacock (Aglais io) is certainly one of our most recognisable butterflies, its showy and spectacular eyespots giving it its common name. These eyespots in fact make up one of three strategies utilised in order to evade predation. The first is known as crypsis and relies on the superb camouflage offered by the dark underwings, making it hard to detect amongst dead leaves. It relies on this during its period of hibernation, but if disturbed it'll step things up a gear. It'll suddenly flash its wings, using those superb eyespots to temporarily 'shock' a predator. In fact, if you view a Peacock from upside down the body appears as a 'beak' and the wing spots its 'eyes.' It may not fool a human, but then of course that's not the idea. Research with Blue Tits has shown the tactic works remarkably well on predatory birds. If still insufficient, the butterfly will accompany the display with a 'hissing' sound,' formed by rubbing the surfaces of its wings together - amazingly this is audible to human ears. Should all fail, the eyespots provide a suitable diversion away from its vulnerable body parts (most birds will attack eyes first).

Another reason the Peacock is perhaps so well known to us is the sheer length of its lifespan. Admittedly it may spend a great deal of that time in hibernation (possibly up to eight months) but may still live for close to a year in all. It overwinters in adult (imago) form and emerges in spring to reproduce, nectaring on early flowers such as those of Sallows, Primrose and Bluebells. It should also be noted that sunny winter days will sometimes bring peacocks out of their slumber, so don't be surprised to see one emerge from your shed. The males are certainly territorial and any dark shape flying by will typically attract its aggressive attention. Once a receptive female has been found, mating can commence and eggs are typically laid on Common Nettle. In their final larval stage (5th instar) the caterpillars appear more like weapons, covered in formidable looking spines. 

Their widespread distribution sees them covering almost every part of the UK and they can be found at altitudes of up to 2500m in Europe and Asia. No doubt the majority of us have seen one, but it would seem a shame not to truly appreciate their superb beauty. They're so exotic they really wouldn't look out of place in a tropical rainforest. Their magnificent colours are in fact created by thousands of tiny scales attached to the wing membrane. These overlapping scales help to create an effect known as 'constructive interference' resulting in the sublime layers of colour we're so familiar with.