The chill of autumn has moved in. Ice is found on puddles and edges of ponds. And early snows have begun, too. Among the bare trees, we expect to see only the warm-blooded animals that can cope with the Northland cold. But as often happens with nature, there is more to be seen.
We don't expect to see insects and spiders at this time, but nearly every day (and night) they are here. As the sun of the late afternoon descends, we may see spiders ballooning. Tiny spiders recently hatched now disperse to find a wintering site. Among the bare branches of shrubs, we may also see a few spiders still in their webs. The flat sheet webs of the hammock spider are formed late in the season, and here they hide in nearby curled up brown leaves.
In open areas near the woods, a few kinds of crane flies perform their late afternoon aerial dances. The rising-falling pattern is repeated often during these chilly afternoons. What may appear to be a swarming insect attack is a harmless mating display usually done only by males.
They are not interested in biting us, and many are incapable of it.
Out on the trails, roads and sidewalks, we can see the active parade of woolly bear caterpillars. These larvae of isabella moths wander about on fall days searching for wintering sites. Unlike most of their kind, winter is spent not as eggs or cocoons, but as caterpillars. The furry black-brown critters go dormant beneath leaves on the ground; their sole source of protection, during the coldest times.
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Maybe the most impressive insect flight at this time are those of the late-season moths. Not much for color, the moths that appear at this time vary from a light gray to brown and are basically two kinds: linden loopers (or winter moths) and fall cankerworms (also known as spanworms). Both types carry names assigned to their inchworm larval stages that feed on the leaves of maple, oak, apple, cherry, and basswood. Most have undeveloped mouths and are unable to eat as adults. They survive on stored food from their younger days. Adulthood does not last long. Now as adults, they go out to find mates. Only the males fly; females are wingless and hide on the ground. In the chilly evening of this time of year, we are a bit surprised as they arrive at our windows after dark, or we spot them fluttering in the car headlights as we drive home in this early darkness.
Sensing the cooling air, these moths find that now is a time of few predators and a good time for their short maturation time when they mate and lay eggs. Constantly shivering their wings, they are able to generate heat and stay warm and so remain active on autumn nights; another marvel of an insect adapting to a unique life cycle.
Larry Weber is author of the "Backyard Almanac" and "Butterflies of the Northwoods." He lives in Carlton County and teaches natural science at Duluth's Marshall School.
