The Long-tailed Blue, Lampides boeticus, (Linnaeus, 1767) is one of the most widespread butterflies in the world, being found throughout southern Europe, Africa, southern Asia, India and Australia, extending eastwards to parts of Oceania including Hawaii; however, it is one of the rarest migrants to the British Isles. Despite its size, L. boeticus is a powerful flyer and there is evidence of regular northerly migrations, not only in Europe but also across Asia, followed by a reverse migration in the autumn (Thomas and Lewington, 2010). As a multivoltine species (having two or more broods or generations per year), winter survival in Britain, or indeed anywhere north of the Mediterranean region, is highly unlikely (Emmet and Heath, 1989; Asher et al., 2001).
The first recorded British examples came from the Brighton Downs in East Sussex in July and August 1859, with another being recorded from Christchurch in Hampshire during August of the same year. As of 1st January 2013 there had been just 22 confirmed sightings of adult Long-tailed Blues in Sussex, plus both wild and accidentally imported larvae; with East Sussex being by far the most favoured area. 1945, a good year for many migrant species, produced 5 adults and 2 larvae in Sussex. There were 38 British reports in 1945, accounting for around a quarter of all British sightings to that date. 1990 produced the next major immigration, with more specimens being recorded than during the great immigration year of 1945. Sussex sadly saw none of these, and since 1945 only 8 adults and 3 larvae have been officially recorded in the county; the last in 2007 when a single larva was found feeding in a pack of organic baby sweet corn imported from Thailand (Pratt, 2011; Thomas and Lewington, 2010).
In addition to the above records, 2013 has produced a good number of confirmed immigration reports from other locations, including a male from Dawlish Warren National Nature Reserve, Devon, on Friday, 26th July; a singleton from a private garden in Dover, Kent, on Tuesday, 6th August; at least 6 individuals, including egg-laying females, from Kingsdown Leas, Kent from around Sunday, 11th August; a male from Dunwich Heath, Suffolk, on Thursday, 15th August; a female from Sandy Point, Hayling Island, Hampshire on Saturday, 17th August; a male, in a private garden in Brighton, on Friday, 23rd August; and, whilst undertaking a seawatch for Balearic Shearwaters on Saturday, 31st August, Jacob Everitt observed a female Long-tailed Blue fly in off the sea at Splash Point, Seaford in East Sussex.
Asher, J., Warren, M., Fox, R., Harding, P., Jeffcoate, G. and Jeffcoate, S., 2001. The Millenium Atlas of Butterflies in Britain and Ireland. Oxford: Oxford University Press, pp. 298-299.
Pratt, C. R., 1981. A History of the Butterflies and Moths of Sussex. Brighton, East Sussex: Borough of Brighton, Booth Museum of Natural History, pp. 50-51.
Pratt, C. R., 2011. A Complete History of the Butterflies and Moths of Sussex. Peacehaven, East Sussex: Colin R. Pratt, 2, pp. 182-183.
Thomas, J. and Lewington, R., 2010. The Butterflies of Britain & Ireland. Gillingham, Dorset: British Wildlife Publishing, pp. 108-109.
UK Butterflies. www.ukbutterflies.co.uk (Accessed, 28 September 2013).
Sussex Butterfly Conservation. www.sussex-butterflies.org.uk (Accessed, 28 September 2013).