Sep. 15—By the time we get to mid-September, one week from the equinox, the summer is waning. However, summer doesn't quickly morph into autumn. Many days are still quite warm blended with chill, even some frost.
This is the time of migration triggered by later sunrises and earlier sunsets, mostly seen with birds now, especially hawks, kestrels and bald eagles at Hawk Ridge. Other raptors — geese, blackbirds, flickers, warblers and finches — are passing through as well. Migration of another kind is seen with insects: monarchs and green darner dragonflies.
Most of our local resident insects do not migrate. Some will hibernate while others are in their final days after laying eggs. I have been watching hornet nests of two types for the last several weeks. The large gray nests of bald-faced hornets in trees and yellow jackets nests in the ground. Both live colonial lives and use these homes as places to produce and raise the young.
The division of labor as seen in these sites are such that developing larvae are fed by workers. They go out each day, preying on insects and bring back to feed the youth. As the days get shorter, the queen stops laying eggs; no more young are growing and so workers are not needed.
Before succumbing to the autumn chill, they fly about satisfying their own tastes. It is at this time; we may see them come uninvited to our food on porches and decks.
Ants in late summer go through a dispersal. Growing wings, they take off in flights from their underground chambers. After mating in the air, the queen begins a new home. Though green darners migrate, another common smaller dragonfly, meadowhawks, do not. During morning walks among the dew-covered plants, I often see dew on them and their cousins, the spread-wing damselflies. They spent the night here, but will die in the coming season changes.
Butterflies show some variety at this time. While monarchs migrate, others, like white cabbage butterflies, expire in the cold. Mourning cloaks and tortoiseshells will hibernate. Grasshoppers and locusts that abound now face a similar fate after laying eggs in soil.
Another insect that lays eggs in the ground visited my yard recently. While sitting in the shade during a hot day in early month, I looked up to see a strange-looking insect in the grass. The black body was long and thin with short wings. It was flying a bit, but not far. Mostly, the insect with the extremely long tail was walking in the lawn, giving the impression of searching for something. The long, thin body was that of a wasp, but not the usual ones. This was a pelecinid wasp.
The body was about one inch long, but held a very long "tail" of about 2 inches. This "tail" was her ovipositor — what the females use to lay eggs in the soil. Many insects deposit eggs here, but do not have such a long ovipositor. Why does this one?
The answer is that the pelecinid wasp (often incorrectly called an ichneumon wasp) is a specialist and reaches a couple inches into the soil to locate and lay eggs in the larvae of May beetles (June bugs) that live there. The hatched eggs feed as parasites on the larva of this ground beetle. Since the beetles are active in summer, the pelecinid wasp needs to do its egg laying at this time.
I see them every late summer, but never many. And though they are a type of wasp and the long ovipositor may appear to be a stinger, they do not sting. Just another interesting critter of the season.