It is rather ironic that this little butterfly, which was named by a 19th Century British entomologist, does not occur in the UK! Weaver’s fritillary (Boloria dia) occurs throughout mainland Europe, and is found just across the Channel in northern France (see distribution map, below).

It is also called the Violet Fritillary, a name which derives from the violet, or lilac, coloration on the undersides of the hind-wings. I rather like the French name: La petite Violette; it is a small fritillary. Nevertheless, the name goes back to a certain Richard Weaver (1790-1860), who claimed to have captured – sometime in the 1820’s –  two specimens in Sutton Park,  which is now a National Nature Reserve located 6 miles north of Birmingham city centre. These and later dubious finds caused a great furore at the time, when butterfly collecting was something of a national obsession, at least among the upper middle classes in England, and particularly country parsons. The historical details of these finds and the reactions they produced are beautifully described in The Aurelian Legacy (British Butterflies and their Collectors) by Michael A. Salmom. (2)

Another specimen was taken in September 1857 in the Rev. S. Hodson’s Garden, at Cookham Dean, near Maidenhead in Berkshire. It was said to have been ‘knocked down by a village lad with his cap’ and was claimed to be undoubtedly British. Unfortunately, the claim was challenged and discredited. There was it seems, a great deal of credit (and money!) to be had from discovering a species new to Britain, and fraudulent releases and captures were made.

Further finds, occurred near Tunbridge Wells, Kent (c. 1876); near Christchurch, Dorset (1887); Ipswich, East Suffolk (1899); and much more recently on the North Downs, Surrey (1984). The latter was believed to have been a release. The official verdict on all of the Weaver’s Fritillary finds in Britain is that: ‘It is believed that all examples of this species are the result of introductions, either deliberate or accidental.’ (3) Since the species is not known to migrate, I suppose we must leave it there, although if Monarch butterflies can cross the Atlantic, perhaps a little Fritillary could be blown across the Channel? Who knows.

In case anyone does come across one in Britain (!), a characteristic feature of this butterfly is the rather sharp angle of the hind-wing, as shown in the following photograph. All of these individuals were photographed in Somiedo Nation Park, Asturias, Spain, in late August/early September this year. I think they are all males.

Links and References

1. Gallery of distribution maps of European butterflies.  http://www.ufz.de/european-butterflies/index.php?en=22481
2. Salmon, M. A., Marren, P., & Harley, B. (2000). The Aurelian legacy: British butterflies and their collectors. Harley Books.
3. http://www.ukbutterflies.co.uk/species.php?species=dia