Vanessa at night - migrations

[Stan Gorodenski]

Very interesting.  I learned of Orley's work at the 99 Lep Soc meeting
in Arizona and it's not that long ago.

Paul Cherubini wrote:
> 
> Stan Gorodenski wrote:
> 
> > From Orley Taylor's work on the magnetic effects on Monarch orientation, it
> > would appear that Monarchs could successfuly migrate at night, even if
> > they may be blind.
> 
> Yes Stan a few years ago Dr.'s J.A. Etheredge, Orley (Chip) Taylor and
> two other insect behaviorists published a fantastic new finding:
> 
> "Monarch butterflies (Danaus plexippus L.) use a magnetic compass
> for navigation." in the Proc. Natl. Acad. Sci. US 23 Nov 99 96:13845)
> 
> The news of this fantastic "discovery" also circulated
> throughout the popular press .  However, four months later
> the authors RETRACTED their paper. Predictably, this retraction
> didn't get much press coverage so perhaps you never heard
> about it.  Here are the details:
> 
> http://scienceweek.com/2000/sw000602.txt
> MONARCH BUTTERFLY MAGNETIC COMPASS PAPER
> RETRACTED
> 
> This is a cautionary tale, an example of how the extraordinary
> complexity of biological organisms, systems whose
> operating variables are often unknown, can lead researchers
> astray.
> 
> In November 1999, a research team (4 authors at the
> University of Kansas Lawrence, US) reported that fall migratory
> monarch butterflies, tested for their directional responses to
> magnetic cues under three conditions, amagnetic, normal, and
> reversed magnetic fields, showed three distinct patterns: In the
> absence of a magnetic field, monarchs lacked directionality as a
> group; in the normal magnetic field, monarchs oriented to the
> southwest with a group pattern typical for migrants; when the
> horizontal component of the magnetic field was reversed, the
> butterflies oriented to the northeast. In contrast, nonmigratory
> monarchs lacked directionality in the normal magnetic field. The
> authors suggested the results were "a direct demonstration of
> magnetic compass orientation in migratory insects."
> 
> Four months later, in March 2000, the authors retracted
> their paper, noting the following: "The positive response to
> magnetic fields in two experiments cannot be repeated. Further
> experiments show the false positives in these tests result from a
> positive [directionality of movement (taxis)] by the butterflies
> to the light reflected off the clothing of the observers. We
> therefore retract our report. We regret the inconvenience that
> publication of this study may have caused."
> 
> 
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