Glassberg is quite correct.

[Neil Jones]

Dr Glassberg is quite correct to assert that _one_of_the__threats 
to the Miami Blue is collecting.


THe Miami Herald article says.

"A chance discovery of a single colony of the bright blue butterfly 
-- about 30 to 50 insects -- on state land in the Middle Keys prompted
 the association to file a petition in June 2000 for protection of the
 Miami Blue as an endangered species."

Asswuming this is correct we have a single small and therefore vulnerable
population.

The Article goes on to say.
"For Glassberg, every day that ticks by increases his fear that the 
butterfly will be gone forever.
``It's hard to imagine more of an emergency situation,'' he said. 
``The only known colony in the U.S. is this small place in the Keys,
 faced with all sorts of possible threats: hurricanes, butterfly
 collectors, mosquito spraying. Any of those could wipe the Miami 
Blue out.'' "

Now for the logic.

It has been asserted, that no insect has ever been extirpated
by human beings removing individuals from a population. It has also been
asserted that since this is the case it would be unreasonable to prevent
human beings from doing this where the insect species is in danger of
extinction. In order to invalidate the second statement it is necessary
to examine the question of whether the first statement can be
disproved as it follows logially from the first. 

 Gathering individuals from a population could be regarded as predation
by one species on another. In this case the predator being Homo sapiens.
It is therefore necessary to examine whether a predator can affect the
population of a species.

There are numerous examples of this. For example it is well documented
that the hymenopteran parasitoid Cotesia bignelii has an effect on the 
population levels of Eurodryas aurinia. There is even an example of
an invertebrate predator foreign to an ecosystem exterminating entire species.
This has happened with several species of Partula snails on Pacific islands
which were exterminated by a foreign predatory snail.

Invertebrates do have a greater potential for population growth and recovery
than mammals or birds but this does not prove that they are necessarily more
resistant to predation. Over the long term each pair of organisms will
produce, on average, one pair of offspring during its life time. 
Insects have just as many predators as other animals. Increasing the predation
will put stress on the population and could, where the population is small,
cause an extinction.

 I myself have observed several populations of insects where due to the
nature of the lifecycle it would be easy to remove all the individuals. I have
not done so because it would be unethical.

There is of course the well-known example where a documented extinction did 
occur, the British day-flying moth the New Forest Burnet, Zygaena viciae 
ytenensis.

-- 
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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