gene pool and releases
patfoley at csus.edu
Sat Jun 16 10:51:13 EDT 2001
Paul and all,
As we have already pointed out on this list, Monarchs and Painted Ladies seem the
safest candidates for unregulated release due to their migratory habits, BUT ...
Even Painted Ladies occasionally achieve reproductive isolation and speciate as is
evident from the four mainland species of Vanessa. If Australopithecus had
colonized North America and practiced wedding releases, we might have just two
species on the continent. This may seem trivial to you, but the long term
consequences are profound.
Nature has many tricks and we do not know them all. Hybrid dysgenesis, selfish DNA
and runaway sexual selection are evolutionary oddities that could play a big role
in butterfly evolution, but have been little studied. I know from my collaborative
work (with my wife Dr. Janet Foley PhD, DVM) on emerging tick-borne diseases in
mammals that the host-array of an infectious disease can be a shifting, elusive
concept. The tick Ixodes pacificus uses perhaps 200 vertebrate host species in
California, including mammals, birds and lizards. It carries several diseases, one
of which is caused by bacteria of the genus Ehrlichia. This causes occasional
fatalities in humans and horses, but you probably haven't heard about it because
high prevalence is largely limited to the North eastern USA and northern CA, as far
as we know. But we don't know why and we don't what will happen with this disease
next. And epidemiologists, and human and veterinary medical researchers have spent
a lot of time already on this.
What we don't know about insect diseases and parasites is far greater than what we
do.Asher Treat (1975) in his book on mites of butterflies and moths writes that in
1964, one author wrote that "Lepidoptera are mostly free of epizoa". By 1975 Treat
could discuss at least 157 species of mites on lepidoptera. I suspect there are
even more than that, don't you? Do you think we know all the diseases of
butterflies, or their potential for spread? I don't. Is this scientific arrogance
on my part?
Harry Kaya is a top insect pathologist, but he is not a geneticist not an
evolutionary biologist nor an epidemiologist. I am. That doesn't make me right, it
simply means that appeals to authority are chancy things. It is good to hear that
the Monarch pathogenesis work was done. Where was it published?
patfoley at csus.edu
Paul Cherubini wrote:
> Bob Parcelles wrote:
> > I personally feel, as a populations biologist that
> > release may have an effect on the gene pool and and
> > should be used intelligently (which it is not!).
> Pat Foley wrote:
> > It is much harder to study the long-term evolutionary effects of lost
> > geographical reproductive isolation though they are likely to be profound.
> About 90% of all wedding and school releases involve just monarchs or painted
> ladies. Five genetic studies comparing eastern and western USA monarchs and
> two studies comparing east coast and west coast Painted Ladies failed to find
> differences* Also, Monarchs and Painted Ladies exist in all 48 mainland states
> of the USA, and in every county within every state. Ditto for their larval host
> plants (with rare exceptions) Thus no geographical reproductive isolation.
> By contrast, NABA's tells the public on its website:
> "Releasing commercially-raised butterflies into the environment is an act of
> anti-environmental terror"
> "inappropriately mixes genetically distinct populations of the same species"
> "may disrupt migratory behavior of native butterflies"
> "confuses scientific studies of butterfly migrations"
> > It would be good to get more research done on disease transmission
> > in butterflies, but who would fund it? None of the commercial butterfly
> > releasers have stepped forward, and it seems largely their responsibility.
> The largest monarch butterfly breeder in the USA (with the odd name of
> Swallowtail Farms) has gone a step further - this company has their monarch
> breeding stock inspected for parasites and pathogens at regular intervals by
> one of the top insect pathologists in the country - Dr. Harry Kaya - a senior
> entomology professor at the University of California, Davis.
> I am unaware of any insect pathologist that is opposed to releases
> of monarchs and painted ladies within the 48 US mainland states.
> Dr, Kaya, as a matter of fact, arranged to have monarchs shipped to
> him from 250 miles away for release at his own daughter's wedding.
> By contrast, NABA's tells the public on its website that releases:
> "spreads diseases to natural populations"
> Paul Cherubini, Placerville, Calif.
> *one study found a statistically significant, but quantitatively small
> difference in the virulence of a monarch parasite in one monarch sample
> from California vs one sample in Mexico, but this parasite only has "minor
> effects on fitness and reproduction" according to the authors.
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