Suffolk (England) Black Swallowtail -- escape or wild?

Hi - I would say this is a captive escape, especially as the butterfly was found in Eastern England. Lots of butterfly visitor houses at the present in the U.K .

Are polyxenes bred in UK? Why would they be, when machaon is readily available in Europe? I suppose a private breeder might want the US species, much as we'd love to breed machaon, but does anyone know of an individual or business that definitely is actively breeding polyxenes in UK?

Though the prevailing winds could carry a NA species to Europe, it is unlikely. However, "unlikely" populated Hawaii over millennia.

I'm sure there are several people in England rearing P. polyxenes at any one time; I've reared it myself on half a dozen occasions in the past, although not for a few years. There does seem to be an endless fascination with rearing machaon group species so people will go to quite some lengths to get livestock.

Bob

That's probably even less likely than being blown there, although not impossible. Really the most likely explanation is that the female escaped from a UK breeder.

Nigel Venters told me some time ago about how he had planted a Zanthoxylum tree in his Hampshire garden and one day saw a female Papilio polytes busy laying eggs on it. That must also have been an escapee from a butterfly house or private breeder. These things do happen every so often, but generally the foreign species do not establish themselves in the UK.

Adam.

Jon,

Definitely ovipositing, so maybe there will be a colony of them there for a while.

I didn't know that Newman's black machaon bred true, I thought it was a temperature induced aberration - interesting.

Adam.

The great butterfly farmer L.W Newman originally obtained his black Papilio machaon britannicus strain from wild collected larvae and they were certainly not artifically induced. Newman have heard the accounts of a fine melanic variety that was captured at Ranworth in the Norfolk Broads by a fishermen in his landing net in 1921. His son L. Hugh Newman gives a very interesting account of how this happened in his fascinating ' Living with butterflies ' 1967.

" My father had always specialized in breeding Swallowtail butterflies, and when he heard about this remarkable black one he decided to take a trip to Norfolk to collect some caterpillars in the district where it had been found. After wading amongst the reeds for several hours he came upon a patch of feathery Marsh hog's fennel, and found several dozen caterpillars feeding on the leaves and flowerheads. He collected as many as he wanted, and the same evening showed them to the men in the bar parlour of the inn where he was staying. One of the older men there happened to be a reed- cutter who knew the Swallowtail butterfly well, both in its caterpillar and chrysalis stage, and offered to save any chrysalides he found during the winter months while on his job. "
" It was ten years before my father knew for certain that he had this rare black strain in his possession. In the usual way of business we had sold a certain number of Swallowtail chrysalides to clients in various parts of the country when, in June 1930, a schoolboy wrote to us a most indignant letter complaining bitterly that the butterfly which had emerged from his chrysalis was ' a nasty black thing and could he have his money back '. Naturally we wrote at once, apologizing and asking him to return the butterfly to us, giving him careful instructions for packing, and promising generous compensation if the insect turned out to be what he had described. When it arrived my father was tremendously excited to find that it was, in fact, a melanic specimen and with his usual generosity, he sent the boy, a cheque for £7 together with a pair of normal butterflies for his collection. When relaxed and set this ' nasty black thing' was offered to Lord Rothschild for £25, a bargain which he readily accepted. This black Swallowtail, rejected by a schoolboy is now part of his national heritage "

" Two more black Swallowtails were to appear that summer among our own stock, and I can remember how excited I was as I watched them hour by hour to see whether they would mate, but although we tried every possible means the two would not pair, and the normal males had to be introduced into the cage to ensure, at least a black cross pairing, I kept careful records of the results of the pairing between a typical male and our black female, from which ninety eggs were obtained on potted fennel, but the strain must have been weak from ten years of inter-breeding and only forty of them hatched successfully. With the greatest of care we managed to rear eleven caterpillars to the chrysalis stage and we were, of course, on tender hooks to see whether they would emerge the same year as second-brood insects or lie over until the following Spring. Four of them emerged in August, the others not untill the following May, but among the first four there were two melanic butterflies, and the remaining seven, three were black and four normal, giving approximately a fifty fifty ratio, which was exactly what was to be expected. One interesting thing about them was that they were not by any means all similar; in some of them the lighter markings, in fact the whole pattern of the wings, could be seen as though through smoked glass, while the others were entirely sooty black except for the bands of blue on the wings. The original black pair, of which the female was the parent of our small brood, although in a rather battered condition went to Tring as set specimens, and are labelled ab. niger. One of those with the pattern faintly showing was figured by F.W Frohawk in his book ' Varieties of British Butterflies ' under ab obscura".
Another similar to the Frohawk specimen can be seen here.

www.nhm.ac.uk/research-curation/scientific-resources/biodiversity/uk-biodiversity/cockayne/database/taxon.dsml?taxonID=8964&option=typicalbutterflies

Other black melanic Swallowtails Newman bred in this very small series of specimens, were as he mentioned even more extreme examples. The above story shows what one of Britain's finest ever lepidopterists did to obtain his rarities. Not only did Newman go straight to Ranworth Broad after the capture of the first melanic swallowtail. He waded into the fen, found the larvae and with his open nature he later met the locals and was greatly assisted by one of them. In fact you could say ; he came, he saw and conquered.

Peter.

Vernon Brou caught a specimen of Aglais urticae here in South Louisiana in the States years ago. I believe his thought was that is sailed over on a ship traveling up the Mississippi River. Your polyxenes may have come over in cargo from some outside source too.