The Limenitis question

[Kondla, Norbert FOR:EX]

Alex raises some questions on Limenitis:
"As far as the Limenitis are concerned, it may very well be that the entire
arthemis/rubrofasciata/astyannax/weidemeyerii/lorquini  complex is in fact
conspecific since they all freely hybridize in their contact zones and
produce fertile offspring. Their ranges fit one another quite nicely.
Structurally they are nearly similar, are they not? Archippus does hybridize
with astyannax in the Mississippi Valley at least, but apparently produces
only sterile male offspring, and also does rarely hybridizes with arthemis.
It is obviously very closely related to them. What about arizonensis? Is
there any known hybridization with either weidemeyerii or archippus? What is
its true relationship with astyannax? This whole group seems to be in a very
fluid and ongoing continuous evolutionary state. There is obviously genetic
transfer between all of them."
My comments:
This is a really fascinating example which unlike most butterflies has had a
good deal of research and we have some data. But everything is still open to
how one defines a species and how one interprets that data and whether or
not one accepts that the data is even relevant to the issue; eg. some people
think that UV reflectance or lack thereof has taxonomic value while others
do not think that way. Adam Porter (1989 Am. Nat.) published on his look at
the arizonensis/weidemeyerii contact in New Mexico. Hybrids of these
apparently exist but on the basis of electrophoretic comparison of 19
presumptive loci he concluded that these taxa are fully reproductively
isolated. The perhaps shocking conclusion that I came to after looking at
Limenitis literature is that arizonensis has no business being placed as a
ssp of arthemis/astyanax and should be treated as a full species.. Porter
even mentions this in his paper. Further the history of treating arthemis
and astyanax as conspecific may come to an end eventually. See for example
the work of Waldbauer et al in Can. J. Zool. 1988. It was not that many
years ago when everyone blindly accepted Papilio canadensis and Papilio
glaucus as one species on the basis of a perceived 'blending' zone. If we
accepted hybrids as proof of conspecific status then many species of ducks
and geese would disappear from our bird lists :-) I personally have no
problem with good species hybridizing in narrow/relatively narrow contact
zones. Hey, Colias philodice and euytheme are alleged to do this over much
of their range :-)


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Norbert Kondla  P.Biol., RPBio.
Ministry of Sustainable Resource Management
845 Columbia Avenue, Castlegar, British Columbia V1N 1H3
Phone 250-365-8610
Mailto:Norbert.Kondla at gems3.gov.bc.ca       
http://www.env.gov.bc.ca


 
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