It’s December. It’s dreary, cold, and wet. Nary has a butterfly been seen since early November, a foolhardy Cabbage White enjoying the last of our warmer fall days. It is at this time of year that many of us “butterfliers” go into winter dormancy ourselves, or we make up for the lack of flying, scaled insects with flying, feathered birds. I am now counting the days until the first Echo Blue breaks the news of spring, or waiting for a lucky day that a Mourning Cloak might take a saunter on a warm winter day. But now comes a warm spell after a series of cold nights that have brought frosts, and I am expecting the arrival of a dear friend.

There is one Lep that I can count on during this season; one that likes to meet at porches on mild winter nights. It eases my anxiety for the arrival of spring. Operophtera bruceata, The Bruce Spanworm Moth, is one of very few moths that fly specifically from late fall to winter. I have seen Ol’ Bruce, as I call it, during the most miserable of conditions. It has endured through snow, wind and ice. I imagine that Bruce must have been an extremely hardy fellow, to have such a creature of resilience named after him.

In fact, if you see this moth at your doorstep, you are seeing an individual whose name may very well be Bruce; for only the males have wings. The females are small, brown cylinders without wings, emitting a blend of pheromones to attract the males. Once mated, they deposit their eggs into fissures in trees and shrubs, where the eggs will overwinter. The females are not particularly choosy about which tree or shrub, for when you are grounded, it is good to be flexible, as choices are few. The first instar larvae are also capable of throwing threads of silk into the wind and being carried to new hosts. These include maples, willow, aspen, oak and several others.

The natural history of this moth may be more interesting than its looks, depending on your point of view. It is mostly a drab brown moth, with small checks and dashes of black. There are also some subtle bands of cream mixed in. However, this species also has a darker form, one with almost entirely sienna brown forewings, with the tiniest of white flecks and a leading edge of golden and muddy brown. The hindwings are a pale, nearly translucent white. The males’ wingspan averages just under 3 cm. It is a subtle beauty, and one made much more so after many Lep-less weeks.

So look outside your porch on a mild winter night, and you may just find Ol’ Bruce sitting on your doorstep, taking refuge from harsh winter weather. So thank this winter flier for visiting, and wish him luck in his search for his wingless mate.

G’num2010Vol11No1