This week the spotlight is on one of Britain’s most familiar and spectacular butterflies – the Peacock Aglais io which is currently on the wing across most of the country.

The first Peacock I saw this year was on the 12th of April, by no means an early date, sunning itself on the edge of a neighbours bird-bath – I remember the fabulous colours were almost a shock after the monochrome of winter. Just last week I was walking along the edge of a local reservoir and in a woodland clearing I saw this species gliding purposefully over my head, before perching with wings angled at the sun upon a spray of dead bracken. The four namesake peacock-tail eyes set in wings the colour of a cherry tomato are so visually striking that they not only repel predators but transfix human observers – beauty and danger in one.

  • It is placed in the Tortoiseshell genus, the only member not to be called a tortoiseshell. The specific name Io is after the Greek mythological figure; priestess of Hera, lover of Zeus, ancestor of Hercules and Perseus and who’s mother was a nymph.
  • The males only mate once with one female as the females are only receptive just after emerging from hibernation. The males set up territories which they defend vigorously, the territory often has good nectar sources but is primarily to attract passing females.
  • The caterpillars are black, with numerous spikes and are studded with white dots. They feed on stinging nettles and can be seen from late May through June.
  • The large eye-spots are a defence feature to alarm or delay attacking birds in particular. They are also capable of producing a ‘hissing’ sound when alarmed which is made by rubbing special parts of the wings together.
  • This species has actually increased its population by 17% since the 1970’s and expanded its range to include the most northerly parts of Scotland – good news!
  • As with all Nymphalid butterflies the undersides of the wings are very well camouflaged, with complex markings and dark colours; this is for protection whilst they hibernate through the winter.
  • Males have a shorter lifespan than females as they have no purpose once they’ve mated in early spring after emergence.