01 October 2014
Abstract: 2013 was an exciting year for many migrant species, particularly in the southern counties, and the Long-tailed Blue (Lampides boeticus) once again appeared in the UK. This short account details the historic records and start of what was to become a very memorable butterfly season in the southern counties.
|Long-tailed Blue, Lampides boeticus (female)|
Photo © Mark Colvin
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).
2013 has been an exciting year for many migrant species, particularly in the southern counties. L. boeticus has once again been recorded, with the first Sussex record coming on Thursday, 8th August, when a single female was observed and photographed by Chris Glanfield in a garden in Arundel, West Sussex. On Friday, 9th August, an ovipositing female was found in a back garden in Pett village, nr Rye, East Sussex, by Trevor Buttle. The butterfly flew off but was seen to return an hour later when Trevor managed to take a few photos including the laying of an egg. He immediately contacted Ralph Hobbs, who was there within half an hour, but the butterfly was not seen again. A search on the foodplant, Broad-leaved everlasting pea (Lathyrus latifolius), eventually revealed 6 eggs. Another search by Ralph of the same foodplant, 200 metres along the road, revealed a further egg. On Wednesday, 14th August, Ralph found more eggs on the same foodplant growing in a garden in Broad Oak, Brede. Then, on Saturday, 17th August, he discovered 4 recently hatched eggs at Winchelsea Beach. These were located on two different clumps of L. latifolius in gardens about 50 metres apart. Other clumps of the foodplant were also searched at Rye Harbour Nature Reserve, and in Hastings, without success (R. Hobbs, 2013, pers. comms., 18 October). On the same day sightings picked up apace elsewhere, with Dave Harris recording 3 females, and 1, possibly 2 males, in his back garden in the coastal town of Newhaven, East Sussex.
It was at this point that I became interested, and on Tuesday, 20th August, I headed for Newhaven to meet up with Dave Harris. I arrived at midday, weather conditions were perfect, and, despite 4, possibly 5 adults being observed just three days earlier, our search produced no adults; though I couldn't help but feel we were being watched. Without intruding too heavily, on what has to be one of the most wildlife friendly gardens I have ever come across, our inspection of the abundant foodplant produced no eggs or larvae; though I feel that this was probably due to our concern for not wishing to disturb the habitat and therefore not venturing too deep. Heading to a nearby location, a single stand of L. latifolius was identified, and it was upon this that several ova, showing signs of recent larval emergence, were found. As the plant was due to be cut down I collected two racemes, upon one of which, a single ovum, showing signs of emergence, was present. From these two racemes 4 larvae emerged over several days. Returning to the Newhaven area on Wednesday, 28th August, I widened my search for the foodplant and found two small stands of L. latifolius approximately half a mile from the original Newhaven sighting point. A careful inspection of one of the areas revealed boeticus activity and a further 2 larvae were discovered. Investigation of the nearby area produced a brief sighting of a single worn female.
Further to my visit of Wednesday, 28th August, on Sunday, 1st September, Dave Harris, accompanied by Lewes District Council's Community Rangers Daniel Ross and Thyone Outram, carried out a more extensive search of the Newhaven area. This included, more specifically, Castle Hill Local Nature Reserve, where three discrete patches of L. latifolius were found. During the search, an early instar larva and foodplant emergence holes were noted. In addition, one of the last remaining gorse bushes on the reserve had indicative signs, though Green Hairstreaks are also recorded in the area and may have been responsible. On the advice of Steve Teale, Dave also inspected an area around the port buildings at Tidemills, about 200 metres to the east of the River Ouse, and found three larvae on the very first plant inspected (D. Harris, 2013, pers. comms., 19 October).
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.
With confirmed sightings of immigrant specimens coming thick and fast, and, with evidence of egg laying and larval activity from a number of localities, it wasn't long before genuine British born Long-tailed Blues began to emerge. This is not the first time that boeticus has bred in Britain, but it is the first time it has been recorded in such unprecedented numbers.