Xerces Blue

Neil Jones Neil at nwjones.demon.co.uk
Mon May 22 13:56:22 EDT 2000

In article <66.3a1e547.2651a703 at aol.com> Stelenes at aol.com  writes:

> In a message dated 5/15/00 9:30:05 AM Pacific Daylight Time, 
> Neil at NWJONES.DEMON.CO.UK writes:
> Actually the Xerces Blue existed in two forms as I understand it .
> tHe typical xerces form and the form antiacis. The latter had heavily black
> centred white spots. Does anyone know how this compares with the
> Palos Verdes Blue which is obviously a close relation? The Palos Verdes
> has more pronounced hindwing spots which sound just like this.
> For those used to latin the Palos Verdes Blue is
> Glaucopsyche lygdamus palosverdesensis.
> ******************************************************************************
> ********
> main host plant Palos Verdes Blue (palosverdensis):  Astragalus leucopsis
> host plants Behr's Blue (incognitus):  more varied, probably lots of lupines
> main host plant Xerces Blue (xerces):  Lotus scoparius (??)
> Actually, the taxonomic comments made by Neil Jones regarding the less common 
> xerces forms with black centers are not incorrect, I don't think an absolute 
> determination as to spots is possible at this time or maybe ever.  Haven't 
> read the new Western Systematics books comment here but would speculate that 
> the degree of black centers were caused by a cross breeding cline of Xerces 
> with Behr's Blue.  The fact remains that the white spotted form, ssp., 
> species or whatever you wish to categorize as, is what is easy to point to as 
> gone - extinct.  The xerces specimens in the PG museum were especially hairy 
> looking, though their age may have contributed to this impression as they 
> were also somewhat faded looking.  The huge white dots upon sight made them 
> look quite unique, considering I never saw another Blue with no black inside 
> the dots.  I would further speculate that the three kinds of Blues being 
> referred to above in the message more probably formed the advancing edge of 
> their evolution and their forms were effected at least as strongly by the 
> environments, environmentally differentiated behavior, and special aspects of 
> foodplants they were found in as their genetics.  I might not want black dots 
> if I slept near the sand dunes and would welcome an all white-dot mutation.  
> Regarding dot size?  Who knows, but the white ones were definitely more 
> remarkable for ID in flight....Too bad there are no more xerces around to do 
> the behavioral experiments which could further the understanding of this 
> complex.  Perhaps Ms. Hammond can wait on this explanation until her students 
> graduate into the second grade and if we need an extinct poster child 
> butterfly, a holotype all-white dotted xerces is a good way to communicate 
> what is extinct.  Then again, perhaps this is all backwards and the white 
> dots persist in the related type: pseudoxerces which apparently is still 
> around somewhere.  Any info on it would be appreciated.

Actually I think it was a bit more complex. Thomas C. Emmel in his book
Butterflies says" Described by Boisduval is 1852, xerces was first reported 
to be extinct in 1884 by W, H, Edwards, an authority on North american
butteflies. Apparently the forms with heavily black-centered white spots on
 the wings ("antiacis") were then in the majority for the thity years.
The whitespotted forem s(true "xerces") where extemely rare until about 1906.
The white spotted Xerces became relatively predominant again by 1911 and 
apparently was the more common form until the spceis disappreared thrity years

Can anyone shed more light on this?

Neil Jones- Neil at nwjones.demon.co.uk http://www.nwjones.demon.co.uk/
"At some point I had to stand up and be counted. Who speaks for the
butterflies?" Andrew Lees - The quotation on his memorial at Crymlyn Bog
National Nature Reserve

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