Swallowtail butterfly, Horsey, Pat Adams 1/10
Swallowtail butterfly by Elizabeth Dack 2/10
Swallowtail butterfly by Richard Brunton 3/10
Swallowtail butterfly by Miles Attenborough 4/10
Swallowtail butterfly by Julian Thomas 5/10
Swallowtail butterfly by Paul Taylor 6/10
Swallowtail butterfly by Ian Pritchard 7/10
Swallowtail caterpillar by Elizabeth Dack 8/10
Swallowtail butterfly, Ranworth Broad, Graham Harden 9/10
Swallowtail butterfly, Hickling Broad, Derick-Stolworthy 10/10

Swallowtail Butterfly Papilio machaon britannicus

Swallowtail butterflies are large, colourful butterflies that form the family Papilionidae. Swallowtails differ from all other butterflies in a number of anatomical traits. Most notably, their caterpillars possess a unique organ behind their heads, called the osmeterium. Normally hidden, this forked structure can be everted when the caterpillar is threatened, and emits smelly secretions containing terpenes. The adults are often tailed like the forked tail of some swallows, giving the insect its name.

Conservation status

During the 20th century, especially after the Second World War, fenland management ceased and much of this butterfly’s habitat was lost. Today active management of the fenland, where reed and sedge are cut to allow other plants to grow, plays an important part in the survival of the swallowtail in Norfolk. With this continued fenland management, the future for the swallowtail looks brighter.

Related questions & advice

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Did you know?

The swallow-like tails of the swallowtail butterfly play an important part in the butterfly’s survival by mimicking antennae. These, plus two red and blue ‘false eyes’, confuse predators into thinking it is a two-headed butterfly.

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