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Recently I have spent 10 days in San Diego on a family holiday.Being semi-tropical there were numerous exotic plants and butterflies.The most common was the swallowtail.On further analysis I found I had captured on my camera 4 different types of Swallowtail all within a small area.I am posting these out of general interest.
P.J.Underwood

What a treat to have those four pottering about in numbers, PJ. Lovely stuff!

Great pics. P.J. I could watch Swallowtails all day long.

lovely pics PJ !

I envy you!

Being the pedant I am, I have to ask why you say the second one is polyxenes colora and not another zelicaon...

Guy

Guy,
You notice every little dot! The difference as I see it,and in my book-Garth and Tilden-is that the blue spots in coloro go much further up the side.In zelicaon there only appear to be three at the most on each side.But you no doubt will say that there are always variations.I wonder if the different types breed amongst themselves.I think they have a very happy life flitting between the Bougainvilliers and drinking the nectar.
P.J.U.

As Swallowtails of the various species are globally widespread, I have to wonder why our own native species is so limited in its range?
Sure, it uses a foodplant with restricted distribution in UK but why doesn't it breed on more common plants (eg fennel) as does its continental cousin?

Jack

There is considerable interbreeding among swallowtail species. Form nitra of zelicaon is said to be a result of hybridisation of zelicaon and polyxenes. James A Scott, in The Butterflies of North America, p. 170, records an observation of a natural mating of a zelicaon male with a polyxenes female and on p. 169 of the same book he notes, 'P. machaon ssp. seem to hybridize occasionally with P. zelicaon and P. polyxenes wherever they contact them.' He gives more information on various genetic transfers in his descriptions of the species.

Still according to Scott (but confirmed in my other books), there is a rather small range of overlap between polyxenes coloro and zelicaon at the western edge of the southern California deserts - so not really San Diego, but not so far away. I suspect both of your butterflies are zelicaon,with the caveat that all my knowledge is book-learning! I've seen the black form of polyxenes but none of the yellow forms. The pictures in my books don't confirm the theory about the extent of the blue on the uph.

As to Jack's question, continental swallowtails have arrived in the UK with sufficient frequency to infer that they really don't like it there! To the best of my knowledge, no immigrant colony has sustained itself longer than a summer. Perhaps the long, mild winters are to blame. Why and how one group managed to establish themselves in a very particular habitat, with a very particular choice of foodplant, and survive, is a very interesting question. I'd love to know the answer.

Guy

Guy:

Why and how one group managed to establish themselves in a very particular habitat, with a very particular choice of foodplant, and survive, is a very interesting question. I'd love to know the answer.

Does machaon breed in the Netherlands in the same fenny habitats as the Large Copper?

The implication behind my question is when there was a boggy landmass known as Doggerland
https://en.wikipedia.org/wiki/Doggerland
joining England with the Continent, might it have been inhabited by a specialised race of machaon? Is there a similar [presumed relic] population on the eastern side of the North Sea with very specialised requirements?

Jack

I was kindly given a book on the butterflies of Zeeland by a Dutch friend, but unfortunately it's in Dutch, which to me reads like German through a net curtain. With the help of Google translate, I learn that the foodplants there are wild carrot, fennel, angelica, parsnip and rue. So a bit broader in taste than our own fenland swallowtails.

Guy

Cotswold Cockney might like to comment here. I seem to recall that he once told me that he had found machaon ova in Norfolk on angelica.

Jack.

Talking about feeding I couldn't resist this.Is the Humming bird mimmicking the swallowtail or vice versa? Eitherway,the meal looks rather more attractive than the plants mentioned by Guy.
P.J.U.

PJ, your first pic, P cresphontes, is in fact a newly described species Heraclides rumiko (Shiraiwa & Grishin, 2014). The genus Heraclides having previously been split from Papilio (but many seem to want to "lump" the two genera and just keep it as Papilio). Cresphontes and rumiko are visually very similar but DNA studies show them to be quite separate. The paper describing rumiko may be found here http://zookeys.pensoft.net/articles.php?id=4409 . It is very detailed and technical (some of it well beyond my own level of expertise), however this pic from the paper shows the visual differences, and indeed the butterfly in your pic can be clearly identified from these. The location also confirms it.
David Hall.

Thanks David.

Guy

My goodness,what have I found! Thanks Guy.
Here is another one to test your expertise.I like the blue on it.
P.J.U.

Great butterfly. I've often browsed the Adelpha species in books but never seen one.

To the best of my knowledge, the California sister is currently considered a separate species, A. californica, rather than a subspecies, A. bredowi californica. Its slightly more easterly and southerly sister sister is A. eulalia, the Arizona sister. The markings are distinct and yours is definitely californica.

By the way, the previous distinction, of cresphontes and rumiko, was thanks to David (Monet), not me.

Guy

Thank you David.I will go back and check all my Swallowtail pictures!
Guy-here is one of a Californian Fritillary-according to my book-that might be of interest.
Philip

Hi P.J.

I've just picked up that thread.... I wonder what book you used for identification of your butterflies. I was in California 2 years ago and have photographed some swallowtails at Mono Lake and in the Sierra Nevada but have never been sure of what species they were. I have to say that the swallowtails there can be a lot bigger than the ones we find in Europe, they are impressive creatures!
For identification I used a book borrowed from a friend but the pictures were not that good and there were no difference shown between species in the text/pictures. I have seen California sisters in good numbers above San Francisco (Skyline nature preserve) but it was so hot (45 degrees) that day that they were all staying in the shade of trees and branches, I managed to get one picture of one very far away.
I am very jealous of your Anna's hummingbird picture. I have seen hummingbirds (one was so tiny that I mistook it for a hummingbird hawkmoth) but did not manage to get one picture , they were too wary...
Here a list of what I managed to identify:
Bois du Val's blue
Acmon blue
Western Pigmy blue
Ruddy copper
Mylitta Crescent
Hydraspe Fritillary
Northern Checkerspot
Nelson's hairstreak
Sylvan hairstreak
Stella Orange tip
Northwest Ringlet
Buckeye
Common banded Skipper
Great Basin Sootywing
Alkali Skipper
Western Tiger Swallowtail
California Sister
Monarch
Becker's white.
All seen around SF, Sonora Pass, Mammoth Lakes, Chalfant valley.
Although California is far away from Europe, I was surprised to be able to recognise the families easily, there isn't much difference between let's say a checkerspot and a frittillary of the Alps for ex. I can see now the experts proving me I am wrong....
It was a great holiday and also very good for dragonflies the highlight being a desert whitetail at Mono Lake.
Sylvie