Most people's favourite butterfly!
Description
The Red Admiral is a large and active butterfly that is very commonly found in gardens, often seen in close association with humans, and is one of the best known species in the UK. It gives the first impression of a dark butterfly with obvious orange-red and white flashes. Closer to, you can see that the fore wing is the one with the black and white patterns towards the outside, but both wings, closer to the body, are primarily brown edged with orange-red. The overall impression is of a confusing flashing of colours as the butterfly flies, obvious at a distance, perhaps even drawing attention, but potentially distracting and off-putting to a would-be predator. Of particular interest are the small but clear tail flashes, initially an electric blue.
On the underside, the situation is even more interesting, as the fore wing is brightly coloured with the orange and white flashes, but the rear wing is very well camouflaged, allowing the butterfly now to slip its fore-wings inside its rear wings and hide, in order to overwinter in sheltered spots. This is a new pattern of behaviour for the Red Admiral in this country, which used to be an entirely migratory butterfly, thought never to over-winter in the UK.
Distribution
The autumn generation of Red Admirals can be found almost anywhere in the parish from July to November, and may often settle on your garden furniture, your clothing or even your body, as they rest between bouts of feeding off sugar sources such as flowers or rotting fruit! Over the winter however in the south at least some of them tend to hibernate in woods or sheds, and in the spring you are most likely to find these, by now rather tatty, over-wintering individuals on paths looking for mates. Later in the spring, May and June, the spring generation, the offspring of these over-winterers are joined by many new immigrants from the continent. It is quite possible that a Red Admiral you see in Hadlow or Golden Green in late spring or summer may have flown here from France, Spain or even perhaps from North Africa! Summer numbers may fluctuate from year to year according to the level of immigration in that particular year.
Red Admirals can be found throughout the UK, even the Northern Isles. Although numbers have dropped in the last ten years, the long term (30 year) trend is still upward. There may be a southward movement in the autumn, increasing numbers in southern woodlands and gardens at the expense of more northern areas. Surprisingly no-one seems to have looked at the likely "reverse" route of autumn migration from the UK back to the continent. However evidence from Sweden of autumn migration back to Denmark, apparently timed to fit with low intensity southerly winds and warmer temperatures has been shown to occur. Interestingly here they appear to know where Denmark is, flying generally to the West to cross the Baltic channel.
The Red Admiral is found across Europe, Asia and North America. In Europe the butterfly is well known as a continental migrant, moving from south in the Mediterranean in the winter to north in Central/Northern Europe in the summer and back again every year, having a generation in each area according to the availability of nettles in active growth for caterpillars to eat. The same migratory behaviour appears to occur in North America, coupled with some proportion of hibernation (in Texas). In the Mediterranean areas at least there may also be an "altitudinal migration" where the butterflies have a low altitude generation in the winter and a high altitude generation in the summer. With such an effective migratory strategy it is really rather surprising that the Red Admiral appears to be so effectively pre-adapted for hibernation as well! What a clever butterfly!
Life cycle
As the new immigrants arrive each spring, they lay their eggs (individually rather than in clutches) on nettles, and the next generation of adults emerge from July onwards, helping to give the large numbers seen in the UK in autumn. The egg-laying females flutter deliberately over nettles looking for the best sites.
The eggs are light, then dark green, and last for about a week. The larva folds the leaf over itself with silk, chewing the end of the rolled leaf off, and feeds within the tunnel created. It moves on to a new tunnel every few days. The pupa then dangles from a leaf.
Oddities
Like the other Nymphalids, the Peacock, Painted Lady, Small Tortoiseshell and the Comma, the Red Admiral has only four functional legs, the front pair of the six being modified into smaller hair-covered "brush feet". Here is a close-up of the creamy white pair of brush feet of a Red Admiral. They may be involved in sensory perception:
Of the four main Nymphalid species in the UK, all four now feeding primarily on nettles (the Comma historically used to rely primarily on the related foodplant, Hops), two have solitary larvae (The Red Admiral and the Comma) and two have gregarious larvae (The Peacock and the Small Tortoiseshell). The gregarious larvae are able to control their body temperatures and keep themselves warm, above 30C, relatively easily by living in such "clumps".
Predators and parasites
Apantales type parasitic wasps may be at work.
Description
The Red Admiral is a large and active butterfly that is very commonly found in gardens, often seen in close association with humans, and is one of the best known species in the UK. It gives the first impression of a dark butterfly with obvious orange-red and white flashes. Closer to, you can see that the fore wing is the one with the black and white patterns towards the outside, but both wings, closer to the body, are primarily brown edged with orange-red. The overall impression is of a confusing flashing of colours as the butterfly flies, obvious at a distance, perhaps even drawing attention, but potentially distracting and off-putting to a would-be predator. Of particular interest are the small but clear tail flashes, initially an electric blue.
On the underside, the situation is even more interesting, as the fore wing is brightly coloured with the orange and white flashes, but the rear wing is very well camouflaged, allowing the butterfly now to slip its fore-wings inside its rear wings and hide, in order to overwinter in sheltered spots. This is a new pattern of behaviour for the Red Admiral in this country, which used to be an entirely migratory butterfly, thought never to over-winter in the UK.
Distribution
The autumn generation of Red Admirals can be found almost anywhere in the parish from July to November, and may often settle on your garden furniture, your clothing or even your body, as they rest between bouts of feeding off sugar sources such as flowers or rotting fruit! Over the winter however in the south at least some of them tend to hibernate in woods or sheds, and in the spring you are most likely to find these, by now rather tatty, over-wintering individuals on paths looking for mates. Later in the spring, May and June, the spring generation, the offspring of these over-winterers are joined by many new immigrants from the continent. It is quite possible that a Red Admiral you see in Hadlow or Golden Green in late spring or summer may have flown here from France, Spain or even perhaps from North Africa! Summer numbers may fluctuate from year to year according to the level of immigration in that particular year.
Red Admirals can be found throughout the UK, even the Northern Isles. Although numbers have dropped in the last ten years, the long term (30 year) trend is still upward. There may be a southward movement in the autumn, increasing numbers in southern woodlands and gardens at the expense of more northern areas. Surprisingly no-one seems to have looked at the likely "reverse" route of autumn migration from the UK back to the continent. However evidence from Sweden of autumn migration back to Denmark, apparently timed to fit with low intensity southerly winds and warmer temperatures has been shown to occur. Interestingly here they appear to know where Denmark is, flying generally to the West to cross the Baltic channel.
The Red Admiral is found across Europe, Asia and North America. In Europe the butterfly is well known as a continental migrant, moving from south in the Mediterranean in the winter to north in Central/Northern Europe in the summer and back again every year, having a generation in each area according to the availability of nettles in active growth for caterpillars to eat. The same migratory behaviour appears to occur in North America, coupled with some proportion of hibernation (in Texas). In the Mediterranean areas at least there may also be an "altitudinal migration" where the butterflies have a low altitude generation in the winter and a high altitude generation in the summer. With such an effective migratory strategy it is really rather surprising that the Red Admiral appears to be so effectively pre-adapted for hibernation as well! What a clever butterfly!
Life cycle
As the new immigrants arrive each spring, they lay their eggs (individually rather than in clutches) on nettles, and the next generation of adults emerge from July onwards, helping to give the large numbers seen in the UK in autumn. The egg-laying females flutter deliberately over nettles looking for the best sites.
The eggs are light, then dark green, and last for about a week. The larva folds the leaf over itself with silk, chewing the end of the rolled leaf off, and feeds within the tunnel created. It moves on to a new tunnel every few days. The pupa then dangles from a leaf.
Oddities
Like the other Nymphalids, the Peacock, Painted Lady, Small Tortoiseshell and the Comma, the Red Admiral has only four functional legs, the front pair of the six being modified into smaller hair-covered "brush feet". Here is a close-up of the creamy white pair of brush feet of a Red Admiral. They may be involved in sensory perception:
Trosley CP, 17-7-2013
Of the four main Nymphalid species in the UK, all four now feeding primarily on nettles (the Comma historically used to rely primarily on the related foodplant, Hops), two have solitary larvae (The Red Admiral and the Comma) and two have gregarious larvae (The Peacock and the Small Tortoiseshell). The gregarious larvae are able to control their body temperatures and keep themselves warm, above 30C, relatively easily by living in such "clumps".
Predators and parasites
Apantales type parasitic wasps may be at work.
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