The peacock butterfly: identification & life cycle

Peacock butterflies (Aglais io) are spotted in gardens, parkland and woodland in early spring. They're one of the most commonly seen British butterflies, according to the Butterfly Conservation's annual Big Butterfly Count. Read on to find out some fascinating peacock butterfly facts, including what peacock butterflies eat, their lifespan, and how their beautiful wings can be used in self defense.

Peacock butterfly characteristics

The peacock butterfly is a gloriously vibrant addition to the spring scene. To us the colourful eye-spots on its upper-wings, obviously reminiscent of a peacock, are simply beautiful but to the butterfly they are its primary means of defence. If disturbed the peacock butterfly can rub its wings together to create a hissing sound; this combined with its large eye-spots will help to deter predators.

What do peacock butterflies eat?

Peacock caterpillars eat stinging nettles and hops, and the adult butterflies eat nectar from a range of plants, including buddleia (known as the 'butterfly bush' for good reason), thistle, dandelion, teasel and bluebells.

Read our tips for photographing butterflies

Peacock butterfly life cycle

Egg laying time

Over the next couple of months after waking from hibernation the peacock butterfly will lays its eggs, often about 500 at a time and several layers deep, on the underside of stinging nettle leaves. By laying them in layers they increase the chances that some will be protected from desiccation and birds looking for a meal. In the ensuing weeks the adults, which have now lived for almost a year, die of old age.

Peacock butterfly caterpillars

As the adults are dying of old age the caterpillars of the next generation hatch out and start fattening up on nettle leaves. Peacock butterfly caterpillars are black with white speckles and black spikes.

Peacock butterfly chrysalis

In July the peacock caterpillars form chrysalides. The chrysalides are spun onto plant stems for support, and they can be green or grey depending on surroundings. It takes 12 days for a peacock butterfly caterpillar to transform into a butterfly. 

Transformation into butterflies

Peacock butterflies emerge as adults in August and so the cycle goes on. Adult peacock butterflies have a wingspan of 6-7cm.

Peacock butterfly lifespan

Peacock butterflies live for up to 11 months, with several months spent in hibernation.

Hibernation over winter 

It is incredible to think that every year in Britain butterflies manage to survive the harsh winter by hibernating but one of our most striking species, the peacock, does just that

In the weeks leading up to hibernation, peacock butterflies convert some of their blood sugar into glycerol to act as a kind of anti-freeze in anticipation of the forthcoming cold period. Then the peacock finds a safe place with relatively constant temperatures and shelter from the cold winds, such as a hole in a tree or inside a shed. Here the butterfly will fold its wings and sleep, its dull underside helping it to disappear in the darkness.

This strategy means that the peacock is always one of the first butterflies we see in the spring. During March, if we get a warm period of weather, the first peacocks will leave their hiding place to go in search of their first meal of the year.

For more information on butterflies, such as the orange-tip and the red admiral, visit our British butterflies section

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