Population crash of N.antiopa in DK
fnkwp at aurora.alaska.edu
Fri Oct 2 14:50:59 EDT 1998
> Isn't it possible that they are skipping the 2nd brood and will
> wait until spring? This species seems to handle the cold pretty well
> here in the U.S., overwintering at times in the adult stage I believe.
In the more northern parts of North America, _N. antiopa_ has
one brood per year, and in normal years always overwinters as an adult.
The result is that the adults are abundant in spring, absent in mid-summer,
and again abundant in late summer/early fall.
Oddly enough, with the cool cloudy summer this year in Interior
Alaska, _N. antiopa_ was exceedingly scarce this fall (although common
anough in the spring). So the population crash (if that's what it is)
is not limited to Denmark. The other possibility would be that most of the
larvae will overwinter and emerge next summer--a form of opportunism which
is known to occur in other northern species. Are there any confirmed cases
of this behavior for _N. antiopa_?
Other late-summer species in Interior Alaska were scarce as well.
_Polygonia faunus_ and _Clossiana titania_ were present at very low numbers
indeed, although these are normally quite common. It will be interesting
to see how these species do next summer... If _N. antiopa_ is scarce or
absent in the spring, and common in late summer, we would then have strong
evidence for larval (or pupal) overwintering.
fnkwp at uaf.edu
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