The Red admiral (Vanessa atalanta) is one of the most stunning butterflies seen in the UK and is a member of the ‘Aristocrat’ family of butterflies. It easily recognised by its black velvet like wings with striking red bars. Most of the Red admirals seen in the UK during the summer are migrants from Europe and only a small percentage overwinter in the UK. The ones which stay tend to be further south where the climate is slightly warmer allowing them to survive the winter. It is common throughout the UK and numbers increase from March to June as they migrate and start to breed then the population receives a boost in Aug/Sept when the year’s new adults hatch from the pupa.
The eggs can be found on the underside of stinging nettles from May to September. This plant is the main food source of the caterpillar which is very similar to that of the Peacock being black with white spots and has soft spines emerging from each of its body segments. There may be dozens of caterpillars on a plant where they weave a kind of web for protection. They have voracious appetites and soon consume the leaves on which the eggs were laid moving on to find fresh ones. After a few days the damage they cause to the plant and the webs they spin for protection are quite easy for predators to see.
Many of the caterpillars fall victim to parasitic wasps and flies like the Ichneumon fly (Apanteles glomeratus) which is actually a wasp which is widespread and can some years account for the deaths of up to eighty percent of all caterpillars. These predators lay their own eggs inside the caterpillars where they eat it alive then hatch out through the skin forming a row of pupa along both sides of the corpse. Providing the caterpillar survives it will pupate and hatch out into a beautiful Red admiral butterfly. If the weather is warm enough to allow the new butterflies to mature quickly enough there may be a second brood as late as August. The butterflies from this second brood along with some from the first will overwinter in hibernation making them the longest lived butterflies as some will have a lifespan of almost a full year. The life cycle of the Red admiral is identical to that of the Peacock.
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Video: Red admiral on buddliea.
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