Roads and Leps

[Kenelm Philip]

	Mark Walker made some interesting comments on this topic recently
--so I thought I would add some Alaskan observations to the thread.

	Alaska (and the Yukon) have very few roads by lower-48 standards.
In a number of cases, however, the very best collecting a given region
can afford is right by the roadside. Prime examples are the Haines Highway
along the Chilkat River, the Tok Cutoff for the first 7 miles south of
Tok, and a number of side roads off the Alaska Highway east of Delta. I
have spent a fair amount of time at all these--and roadkill appears to be
a very minor factor in butterfly mortality. The main exception to that
rule is the Alaska Highway from Delta to Tok during years of high abundance
for Tiger Swallowtails, when roadkill for that species is quite high (but
still, I would guess, an insignificant fraction of the total area popu-
lation). Of course, traffic levels are low compared to more populated
areas.
	In the case of the Tok Cutoff, the highway runs through a wooded
area--and the trees have been cut fairly far back from the highway to
provide space for power and phone lines. These wide margins have grown up
to a profuse array of flowers, and attract and concentrate butterflies
from the woods.

	There are two other man-made habitats that act as butterfly concen-
trators in Alaska: airstrips, and the gravel pad along the Alyeska Pipeline.
Both of these are disturbed habitats, and tend to grow up with various
legumes--which then act to concentrate various species of _Colias_ as well
as other butterflies. One species of _Colias_, although fairly widespread
in the Yukon, is known to date in Alaska _only_ from three airstrips and
from the margins of a single road. On the North Slope, _Colias_ which are
widely dispersed on the floodplain of the Saganivirtok River are markedly
concentrated on the pipeline gravel pad.
	
							Ken Philip
fnkwp at aurora.alaska.edu