Whatever the calendar says, the week's weather demonstrated that summer is upon us. It isn't just the heat and the humidity. Maybe you've noticed the sudden surge of leggy, segmented life forms outdoors, and indoors, too. As thunder, lightning, steam and sweat have increased, so has the number of arthropods - insects and their kin, as the old natural histories liked to call them. So begins episode one in the sizzling drama of what's shaping up to be a long, hot summer. As the characters take the stage, each tells its tale.
An enterprise I've indulged in since childhood is raising moths. Seldom seen, our largest moths rival our biggest butterflies, not just in size but in beauty, too. The grandest in our neighborhood is the Cecropia moth (Hyalophora cecropia) whose outspread wings often exceed six inches in width. So secretive is this giant that most people have no clue that such an insect exists anywhere but some tropical rain forest. But Cecropia is nearly everywhere in these parts. Its caterpillars eat leaves of common trees - maple, cherry, ash, willow - and also the notoriously invasive purple loosestrife. But the huge, green caterpillars and brownish, leaf-covered cocoons are exquisitely camouflaged. The adult moths fly in the wee hours just before dawn, and rarely come to lights.
This year for the first time, in tune with a social issue of the times, we discovered among the male moths attracted one night to some caged females, an interlocked pair of males. Many years ago when Woodstock was considering a controversial "gay rights" ordinance, in answer to a Christian minister's diatribe on "unnatural acts," we responded with a Nature Walk recounting instances of same-sex behavior in wild animals. The Cecropias shown here were probably not expressing their alternative lifestyle, but rather, aroused by feminine pheromone, reacting to first contact with unbridled passion.
A magnificent moth that did come to our plastic pumpkin porch light aroused our instant admiration for its soft earth tones of wings and body. Its broad, graceful, triangular form and jaunty angle of rest declared it a sphinx moth or hawk moth, and one of our largest, the big poplar sphinx (Pachysphinx modesta). The hawk moths are the ones that come from those big horn-tailed caterpillars, the most common being the lowly tomato hornworm despised by gardeners. Occasionally a hornworm will nibble on a green tomato, but sphinx caterpillars much prefer leaves to fruit, and cause serious damage to plants only when they are unusually numerous.
Another group of unfairly maligned insects is the family Tipulidae, or the crane flies. Two common myths plague this large family: the one that holds that they are gigantic mosquitoes, and the one that purports their prowess as predators of mosquitoes. But as the family scientific name suggests they derive sustenance from (not necessarily alcoholic) fluids, such as fruit juices and less savory liquid fare. These harmless drinkers should be neither vilified nor lionized, but simply admired for their grace and variety.
Insects are also called hexapods, referring to their six legs. Similar creatures (spiders, centipedes, millipedes, sow bugs and others) are often thought of as insects, despite having different leg counts. After insects, spiders are probably the most high profile of the whole leggy lot whose proper name is arthropods, meaning joint-legged. Taken literally, we humans, having jointed legs, should be included, but membership in this joint is denied to vertebrates.
Bad repute is visited excessively and undeservedly upon spiders, whose leg count is eight. The literal "octopod" (more exactly, the equivalent "octopus") was applied long ago to a family of brainy, rubbery marine cephalopods ("head-foot!"). The word "spider," as applied to certain eight-legged arthropods in the Arachnida (from Greek "Arachne" (meaning spider as used here), is derived from the Middle English verb "spithre" (akin to the Old English verb "spinnan"), meaning "to spin."
Not long ago we found that a big spider had taken up residence in a paper bag in our shed. I was a bit perturbed because I needed more paper bags to put female Cecropia and Polyphemus moths in, so they could lay eggs on the sides of the bags. Human respect and kindness prevailed, the spider kept her adopted home, and I found lots of clean paper bags at the dump.
The spider in residence was one of the genus Dolomedes, probably D. tenebrosus, the dark fishing spider, a fabulous name for a fabulous creature. More feral individuals living along streams and pond margins actually go fishing, diving beneath the water to seize their prey. Normally they take insects, but a big fishing spider may make a meal of a minnow on occasion.
Why this species is so widespread and tolerant (perhaps even fond) of human structures is a mystery. This habit brings fishing spiders into harm's way as their presence provokes the defense reactions of people driven by their fear of spiders. Behaviorists, psychologists, sociologists, anthropologists and mythologists have propounded on this and similar phobias, but their hypotheses are never completely satisfying. Like snakes, spiders inspire fascination and fear in many of us, the two mental states curiously merging into a single irresistible obsession.
So let's shine the light of reason into this dark corner. Spiders are not to be feared. They're not worth worrying about in the least. Yes, there are venomous spiders. The black widow and the brown recluse can bite painfully, and their toxins can cause serious damage in allergic or otherwise medically compromised individuals. But for most healthy people a spider bite is at worst a painful or itchy irritation that soon passes. Remember that some people can die from a bee sting, or suffer severely from eating strawberries. The chance of being bitten is very remote. Except for tender areas that seldom see daylight the human integument is too tough to be pierced by a small spider's paltry fangs. Large spiders like garden spiders (Argiope spp.) and fishing spiders have very weak venom; their size and strength make strong poison unnecessary.
As summer progresses, take time to enjoy the "bugs" that come naturally to this time of burgeoning biological activity. It's a special time we biologists call the growing season, the time of green abundance, the opposite of winter. We should take advantage of it, and do some growing ourselves. ++