Large Tortoiseshell

The mysterious disappearance of this beautifully patterned and powerful looking butterfly is a sad affair. In the 55 years between 1950 and 2005, only 150 sightings were reported. Out of these the majority were most certainly releases or escapees of reared specimens and a portion of others misidentifications.

To put it into perspective, the Monarch that lives in the US and the Camberwell Beauty that havd never bred here; both had 10 times as many sightings here in the UK over the same period.

There is only one generation each year.

Large Tortoiseshell (Nymphalis polychloros) - © Andrew Cooper

Distribution Map

Distribution- Historic and Modern

An extreme rarity, presumed extinct as a resident in Britain. There is however a small possibility of spotting one in the south-east of England.

The butterfly was widely distributed in wooded regions of England and lowland Wales.

Until the Second World War it was well established in parts of Essex and East Suffolk, and even earlier it lived as far north as Yorkshire. Apparent permanent colonies were established in the New Forest district too.

It was difficult to establish when the butterfly vanished and where its last held on for its habit to wander made them impossible to count.

A Dramatic Decline

The state of this butterfly in the UK today would be shocking to Victorian butterfly ethusiasts who saw little reason to record the species in the south.

Generally the butterfly would appear in a woodland and breed for a few years, becoming abundant before a period of scarcity and eventual disappearance.

Its rapid decline is partly due to the widespread destruction of Elm trees, its main foodplant, by Dutch Elm disease since 1970. The caterpillars may now become increasingly dependent for their on Willow, Sallow, Aspen, Whitebeam and Birch trees. However attack from ichneumon wasps takes a heavy toll of the ctaerpillars, killing as many as 99 percent of colonies each year and placing a severe limitation on any increase in Britain's Large Tortoiseshell population.

The Victorian Edward Hulme wrote: 'a patch of spear-plume thistles in an open clearing in the wood, and here we shall probably find in plenty the Red Admiral, the Peacock and the Large Tortoiseshell'.

Large or Small Tortoiseshell?

Many misidentifcations of the Large Tortoiseshell have actually been mistaken for the similar looking, widely distributed Small Tortoiseshell.

In truth, the Large Tortoiseshell is more closely related to the Camberwell Beauty than the similarly marked Small Tortoiseshell.

The two Tortoiseshell butterflies actually differ very much from one another. Their names give an obvious clue; different in size, the Large's colours are dull, and its food plants are completely different.

The butterfly is found beside country lanes and at the edge of woodlands, particularly where Elm trees grow, rather than on Stinging Nettles and in gardens. Nobody can deny however the resemblence in the Small Tortoiseshells wing design, its hibernation sites, and its long life of about ten months as a butterfly.

Habits-

The Large Tortoiseshell is an active butterlfy that flies through the countryside laying eggs wherever it happens to stumble across suitable conditions.

The butterflies habit to wander with no fix home made it extremely difficult to count and establish when it vanished. Some even believe there are areas where it may have held on but apart from a few sightings there is no evidence.