Treasures of the Dalean Collection. Lepidoptera & Coleoptera

Dale's Swallowtails

The Dale series of 21 specimens of Papilio machaon is of great historical interest. Not only does the collection contain specimens from the long extinct population at Whittlesea mere, that researches can compare to those extant populations in the Norfolk broads, it contains several genuine British specimens of subspecies gorganus. A number of specimens of subspecies brittannicus were caught by J.C Dale and his friend B. Standish between 1819-1821 at Whittlesea mere in Huntingdonshire, where it used to occur in great plenty. The Swallowtail became extinct at Whittlesea in 1851, when the great mere and fen were drained. There is also a specimen of brittannicus with the label- Bardolph Fen ,caterpillar Norfolk June 1820 [ J.C.Dale] turned to butterfly July 4 1820. Other 19th century specimens of brittannicus are from Wicken Fen in Cambridgeshire, the last known locality outside of the Norfolk Broads. It was last seen at Wicken in 1952. There are also a number of specimens of subspecies gorganus collected by J.C. Dale in his parish of Glanville's Wootton in Dorsetshire. Dale recorded gorganus at Glanville's Wootton every year between 1808-1816. The last specimen of gorganus from Glanville's Wootton was taken by J.C.Dale  in August 1815 at Newland's common , although he saw another visiting a thistle there in 1816. It is known from the records that subspecies gorganus was able to temporary establish itself in a number of places in southern England during the 19th century. There is also a specimen of gorganus in the Dale collection from Dover. There is the curious case of George Austin writing in 1856 who recalls he was accustomed to finding the larvae of P. machaon in the Osier Beds behind Battersea Fields in South London, but he never saw the adults. Because of the habitat it is thought Austin was referring to brittannicus, but more likely the larvae that he obtained may have belonged to subspecies gorganus.


P. machaon brittannicus collected by J.C Dale on August 7th 1820 at Whittlesea mere in Huntingdonshire.



P. machaon brittannicus aberrant.


P. machaon gorganus female, the last ever specimen of this subspecies that Dale took on August 17th, 1815 at Glanville's Wootton.

You're probably right that foodplant is not a distinguishing character in subspeciation; I've reared britannicus on several other Umbellifers in captivity, it will also reluctantly take some Rutacae.  I've also found ova of gorganus on both Ferula and Foeniculum at the same site.

I think the habitat preference as well as the very different habitus is enough to distinguish britannicus as a good subspecies. In the right habitat it can be very common; the opportunity is there for it to spread into other habitats but it has never taken it.

Bob

I am pleased that you enjoyed the piece dunc. Yes, it is wonderful the specimens that were caught so many years ago still look quite fresh today. This is because, the Dale collection has received the proper attention it deserves. I believe today they now freeze the drawers regularly. It is true that our P. machaon subspecies britannicus was widespread across the East Anglian Fens. Perhaps it also once occurred in the Somerset levels and along the Thames marshes? Other southern England populations that occurred in different habitats should be attributed to subspecies gorganus. Many lepidoptera will take other foodplants in captivity rather than starve, however in the wild the larvae of subspecies britannicus are nearly always found on Milk Parsley. I believe that in captivity, what the British Swallowtail larvae may feed on, when their foodplant of choice is not available, does relate to subspecies britannicus very long association with Milk Parsley in its fenland habitat. Subspecies brittannicus never utilizes other widespread Umbellifers, otherwise it would be found in a range of habitats, just like the continental gorganus. Furthermore, there are clear morphological differences. The British britannicus have more extensive darker markings than gorganus. For the full differences, see E.B. Ford - Butterflies [ 1945] page 302. Although the British Swallowtail from different fenland localities may have been all similar, those historical specimens build a good picture of where the Swallowtail occurred and how widespread it once was. Attempts to reintroduce this butterfly to Wicken Fen have failed, the water table is now too low and the habitat has changed. Perhaps they will try to introduce  this lovely butterfly to the Somerset levels where I believe the foodplant still occurs. I have heard talk of this.

A fine variety of Melanargia galathea

The Marbled White [ Melanargia galathea ] is easily the most striking of the British satyrids. In the Dale collection there is an outstanding dark aberration from the early 19th century, that is labelled Mr Le Plastrier Dover. It seems that Mr Plastrier was a very lucky collector [ see the A. aglaja post ]. This fine variety was figured in the London Magazine of Natural History with detailed drawings by the Reverend William T. Bree in 1832. Later, the Reverend F.O Morris, a good friend of J.C. Dale, pictured the Le Plastrier Melanargia galathea specimen on a fine plate in his, A History of British Butterflies that was published in 1853. It can be seen from both the Bree and the Morris figures that this fine aberration also has a very different verso side. William Bree was the Rector of Polebrook in Northamptonshire and was well known to British Entomologists by his interesting accounts of the Large Blue [  M. arion ] that he discovered at Barnwell Wold during the 1830's. In the Dale collection there is also a specimen of M. galathea with a buff ground colour, which has the data J.G. Ross 1879, another collector who had phenomenal luck in the field. Below the Ross specimen is an aberration with broad black margins and much reduced hindwing white-markings. Peter.



Dale's fine var. The historic early 19th century Le Plastrier Dover specimen.


The William T. Bree figure of the Le Plastrier specimen. The London Magazine of Natural History - 1832.


A colour plate showing the Le Plastrier M.galathea specimen. From A History of British Butterflies by F.O Morris - 1853.


Two other aberrations of M. galathea in the Dale collection. The top specimen was taken by J.G. Ross in 1879.

Peter

Obviously when Dale's collection was formed nobody was aware that there were two different species of "pale clouded yellow". It's not too difficult to identify them when you get your eye in but it takes a while. When I was sorting out the 500+ specimens in my collection I quickly was able to separate them with 99% accuracy; just looking at these photos having not really studied them for a few years it's a little more difficult. However I would say that top two males in your 2nd photo are C. alfacariensis but the one below them is hyale; all the specimens in photo 4 seem to be hyale.

I've looked at quite a lot of "British" hyale and in my experience about 75% are alfacariensis. This makes sense when you look at their distribution on the near continent.

Bob

Thanks Bob for the ID. I thought those two might be C. alfacariensis. I have corrected the latin name for the Clouded Yellow = C croceus. It is amazing that no one recognized until 1945, that there was another species of Colias in Europe and that it had been collected in Britain long ago in the early 19th Century. The Belgian entomologist who discovered this, L.A Berger must have been very pleased.  James Dale would have been most surprised. Looking again at the Dale specimens, I am amazed at their condition, especially as some of them are nearly two hundred years old! Below are two of my images of two different female C croceus that I managed to photograph on the Wiltshire U.K. Downs, August 2013 .


C. croceus female feeding at Wild Basil [ Clinopodium vulgare].


C. croceus female resting on  Woolly-headed Thistle [ Cirsium eriophorum] during dark cloud followed by rain. Well camouflaged.