Thursday, January 1, 2009 - Vol. VIII Issue 1
Little Critters Cope with Winter
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Winters in
Wyoming are long and harsh. But even during mid-winter, there can be a warm
day with the sun shining and little wind. The Angle Wing Butterfly (Polygonia
faunus hylas) overwinters as an adult butterfly. When it is not
hibernating it may come out and fly even when snow is on the ground. The
caterpillar feeds during the short summer months.

Angle Wing Butterfly Photo by John Nordin, 14 September
2008, Green Rock picnic ground west of Laramie, elevation 9800 ft. The 1.5
inch-sized butterfly spreads its wings in the sunlight while feeding on sap
oozing from a pine tree on a chilly morning.
The Chryxus
Arctic (Oeneis chryxus) takes two years to complete its life cycle.
The butterfly overwinters as a caterpillar during two winters, eventually
pupating and emerging as an adult butterfly during the second year. The
caterpillar produces a special antifreeze to keep ice crystals from forming
within its body during the winter, where temperatures can drop to less than -40oF
at 10000 foot elevation where it lives.

Chryxus photo by John Nordin, 20 July 2008, Snowy Range
Pass, Elevation 10800 feet. Butterfly about the size of a half-dollar.