Alaskan moth stray

[Jeff Crolla/Martha Hancock]

James, based on the evidence so far I think I also would lean toward this
moth having made the trip under its own power - might be worth checking to
see if there were any strong "trans-oceanic" storm systems/airflow in the
period around 23 June. If it had shown up around a major port around the
alaskan mainland for example, I would incline more toward the stowaway
theory, but after looking at a map and finding that Buldir Island is just a
speck of land at the far western end of the Aleutians (not far from the
famous - in ornithological circles at least - Attu Island, which is well
known for a star-studded list of vagrant Asiatic birds including many North
American firsts), the unassisted (except meteorologically) flight seems
quite credible and maybe more likely.

Also, I don't think the fresh condition of the specimen is necessarily an
argument against a long wind-assisted flight. Quoting E.B Ford in
Butterflies (1945)  in refeernce to european vagrants in Britain:
"..Lepidoptera are much more quickly damaged by contact with grass and
bushes than they are by sustained flight. Migrating specimens do not
encounter such obstacles, and therefore they often arrive after immense
journeys almost as if newly emerged. The statement is constantly made that a
rare species must have bred in England because an example of it has been
obtained here in perfect condition. This is quite worthless evidence [his
rather strong wording, not mine!]". As you say the question of origins in
cases like this is always difficult, but given the location (and that I'm
not sure why one would suddenly leave a ship near the western end of the
Aleutians) I think the possibility of it being a vagrant under its own power
is pretty good, although perhaps it would be more likely in the fall with
typhoons etc as Roger Kendrick mentioned. There are at least 3 records of
the south american Eudocima materna from Canada in the fall associated with
ex-hurricane systems I think. Just my 2 cents.

Jeff Crolla


----- Original Message -----
From: "James Kruse" <fnjjk1 at uaf.edu>
To: <leps-l at lists.yale.edu>
Sent: Wednesday, October 17, 2001 08:45 PM
Subject: Re: Alaskan moth stray


> It should be possible for the species to fly by it's own if the winds have
> been from SW. In fact I think it is far more likely that the moth did it
by
> itself! A. tyrannus is native or regular also in the Russian Far East
where
> many "subtropical" species occur mixed with the boreal ones - especially
on
> the coast.

Okay. My reasoning was that the specimen was very fresh looking, and some
major transcontinental shipping lanes go pretty close to it. All this and
the genus has a history (E. materna especially) of hitching rides on
vehicles such as ships. Of course, the genus also has a history of long
distance flight dispersal. So more likely? maybe. Far more likely? I don't
know.

James J. Kruse, Ph.D.
Curator of Entomology
University of Alaska Museum
907 Yukon Drive
Fairbanks, AK, USA 99775-6960
tel 907.474.5579
fax 907.474.1987
http://www.uaf.edu/museum/ento




 
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