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Published by jack elliot

British Butterfly caterpillars  feed on Nettles

Many people don’t like Stinging Nettles (Urtica dioica) because they sting and are thought of as weeds but a lot of these same people don’t realise just how many pretty butterflies have caterpillars that depend on these plants. In the UK, the Small Tortoiseshell (Aglais urticae), Peacock (Inachis io) and Red Admiral (Vanessa atalanta) are the three main ones. The Painted Lady (Cynthia cardui) and Comma (Polygonia c-album) are two more that have caterpillars that will eat the plant.

So if patches of nettles are destroyed there go the homes and food-plants of some of the prettiest butterflies in Britain. Sadly this is often happening with the increased use of the Roundup herbicide made by Monsanto. It is sprayed all over the nettles and leaves death and destruction in its wake!

 

The Small Tortoiseshell has been one of the commonest and best-known British butterflies. Often seen in gardens, especially in summer and autumn, this butterfly is very pretty with its orange-red wings that are attractively marked with black and yellow, as well as blue spots in the dark borders to the wings. The upper wings contrast strongly with the dingy dark brown of the under-wings.

The Small Tortoiseshell is in the large Nymphalidae family, as are all the other Britsh butterflies with caterpillars that feed on Stinging Nettles. It used to be seen in great numbers feeding on Buddleia, or the Butterfly Bush, as it is also known, on Michaelmas Daisies, Stonecrops, and may other garden flowers. In late summer and autumn these butterflies would often be seen in parks and gardens, even in busy cities and towns.

Sadly in recent years the numbers have been dropping fast, especially in the southern counties of England. Various reasons have been suggested.

It is thought that Climate Change with wet summers and a parasitic fly are to blame but I think the widespread destruction of Stinging Nettles is a major threat to this butterfly’s survival. Herbicides like Roundup are often used to get rid of patches of the plant in public areas and fields.

 

The males and female Small Tortoiseshell butterflies look identical but the males are usually smaller. They can establish territories but these insects will also gather in numbers on flowers they are feeding on. They pass the winter in hibernation as adults.

The caterpillars live in colonies on the Stinging Nettles and spin a web over it as they eat it away. In their last stage before they pupate they become solitary but often sun themselves on the tops of leaves. They are blackish or dark-grey but marbled with yellow to varying degrees.

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