A KIND WORD FOR A CANNIBAL
Nobody loves the spider. Yet she’s less harmful than a fly, and she did help us to win the war
C. FRED BODSWORTH
MOTHER GOOSE'S naive Miss Muffet is responsible for mythology's major false alarm. When she abandoned her tuffet in
terror she raised a furore which the innocent spider folk have never been able to live down.
Among all the world’s creeping and crawling creatures, there is probably none that is so feared, despised and misunderstood. Yet the spider’s record with mankind is practically blameless. Every day spiders kill countless crop-destroying and disease-carrying insect pests. But do we regard the spider as an ally? No. We squash his fly-filled body against the ceiling or floor, because, like poor Miss Muffet, we’re afraid he’s going to bite us.
It’s true that spiders bite. But they prefer creatures with cold blood, and they’ll use their fangs on warm-blooded chaps like you and me only in self-defense. Every spider possesses a venom which he uses to kill other insects of his own size for food. He has a pair of curved fangs that meet like caliper points and inject a minute shot of poison. But most spiders can’t pierce human skin. Of the larger spiders, only two in the world are more dangerous than honeybees. One is an Australian species and the other our own notorious
black widow. On rare occasions these black sheep of the spider family have caused the death of humans, but even the black widow is not as black as painted.
It is difficult to get yourself bitten by any spider. Naturalists and doctors hold them on the soft parts of their arms, pinch and tease them, but still often spiders as big as teacups refuse to nibble. In the southern United States, where black widows are reared commercially on spider “farms” for their silk, the operators are rarely bitten.
Suppose you do get a bite. It is probably a little more painful than a mosquito’s, probably less painful than a wasp sting. In a day, unless you are abnormally allergic, the bite will have disappeared. The death toll in Canada every year from houseflies is greater than that inflicted throughout the whole world by spiders, yet the average housewife blithely ignores the flies and runs like Miss Muffet.
The black widow, however, rates a warning.
She’s the only spider in North America that can kill a man. (You have to speak of the black widow as “she,” for the male is a harmless dwarf less than half her size.)
Drop for drop, the black widow’s venom is more potent than a rattlesnake’s. Fortunately, far less poison is injected. All other spider venoms produce only a local effect. The black widow’s venom spreads throughout the body.
The original bite may be no more painful than the prick of a pin. It may show as two minute red dots surrounded by a slight white swelling. But within three or four hours there may be pains throughout the entire body. Sometimes breathing becomes difficult because of partial paralysis and the victim may suffer from amnesia, nausea and fever.
Doctors say calcium gluconate is the most effective antidote. Even without treatment the effects on a healthy
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person wear off in two to four days. Prof. W. J. Baerg of the University of Arkansas, who for research has allowed himself to be bitten many times, says: “The bites do not leave any noticeable aftereffects. The patient always recovers (excepting possibly infants) unless the recovery is hampered by complications such as a very weak heart, or a syphilitic condition.”
The black widow is a shining black spider with a large round abdomen, about half an inch long. She usually has a small red spot on the upper surface at the rear of her abdomen and a large red blotch shaped like an hour glass on the abdomen’s lower surface. She is common in the southern states. In Canada she can almost be called common in southern British Columbia and Alberta, but not elsewhere. One was caught in Winnipeg recently and in Ontario it has been discovered twice along the shores of Lake Erie. Few Canadians have been bitten and there are no records of a Canadian having died from a black widow’s bite.
The spiders are a big clan. Some 25,000 species have been identified and named, but because of a lack of scientific study no one will guess how many other hundreds of unnamed species there are. Thousands are no larger than the head of a pin. The huge .South American tarantula has a body two inches long and a leg span of seven inches. This giant sometimes captures small birds but its bite, though extremely painful, never causes death to humans.
Not Romantic Type
Canada’s spiders offer a vast field of research. Only two Canadians have made a special study of them. They are T. B. Kurata, entomologist at the Royal Ontario Museum of Zoology in Toronto, and Stanley Harrod, also of Toronto. Collecting spiders is Mr. Harrod’s hobby.
Mr. Kurata says that there are still probably a great many spiders in Canada “waiting for some young naturalist to come along and have the honor of naming them.” Next time you squash a spider in your own home you may be killing a creature that the scientists have never seen.
There are probably more than 1,000 species in Canada. In the Royal Ontario Museum’s spider collection are 600 species, mostly from Ontario. In Harrod’s private collection are 300 species, all found within 30 miles of Toronto. Two are new and one will bear the scientific name “Harrodi” in honor of the discoverer.
Mr. Spider is nature’s most henpecked husband. He’s a puny midget and a shiftless ne’er-do-well, barely capable of building his own crude web. The only time he eats well is when he can move in on the web of a hard-working lady. He dines on the scraps of her table—but he is in danger of being eaten himself. In most spiders the male is six to 10 times smaller than the female and the lady usually drives him out of her web several times before tolerating him. If he is slow in retreat she will make a meal out of him—or at least a mouthful.
There’s no romance in her tiny, cold-blooded heart. If her eggs are at the stage where they require fertilization, she’ll accept her mate’s advances. Then she turns her deadly fangs against the father of her 500-odd children-tobe. Male spiders rarely survive one betrothal.
As a mother she deposits her eggs in a silken, waterproof bag, then stands guard prepared to fight to the death to protect them. If she chooses to move to a new home she wheels the egg sac in front of her like a baby buggy or tows it along behind. When the youngsters are ready to see the world, she snips the bag open and the babies swarm out around her. Many species then carry the youngsters around for several weeks on their backs. If one drops off it scampers up the closest leg for a new perch.
But Ma Spider is a cannibal. If flies are scarce and her brood becomes hungry, she simply kills a baby with her calipers and serves it to the brothers and sisters. In some species the mother dies in the autumn and leaves her babies in the egg sac until spring. There brother eats brother and sister eats sister in an orgy of slaughter all winter. By spring there may be only a dozen or two of an original family of 400 or 500. A few years back 55 adolescent black widow spiders were placed in a jar at the Royal Ontario Museum of Zoology in Toronto. Three weeks later the 55 little spiders had transformed themselves into one big fat one.
A Great Home Builder
Spider silk has more uses to the spider than has steel to engineers. Furthermore, it is many times stronger than steel drawn to the same diameter. For its size, it is the sturdiest product in nature.
Every species spins a distinctive web. Most spiders have about seven spinnerets at the rear tip of the abdomen, each spinneret producing a different quality of silk. The spider can turn on whatever one he wishes at will. The silk is produced from a liquid which hardens in contact with air. With it the spider fashions its home and banquet table, its nursery, trap lines, telegraph systems, bridges, speed highways, lassos, aerial balloons, baby blankets, alarm systems and escape routes.
Some day you may observe a spider erecting her home. Sit down and watch. It’s a construction feat worthy of an audience.
First she sets up a framework of reinforced foundation strands between a couple of twigs or grass stems. Then she puts in a central span, the centre of which will be the hub of her wheellike web from which all of the 25 or 30 spokes will radiate. Here is where her geometric and engineering skill shows up.
She glues the first spoke’s tip to this central point, then spins out the strand as she climbs to the reinforced foundation line above. Carrying it along the foundation line, she attaches it so that (if she’s a 25-spoke spider) the angle it forms at the hub is just one 25th of 360 degrees.
Spoke after spoke is placed in the same way, every angle exactly the same. But she’s too clever to go around the circle, setting in the spokes consecutively. She lays down a spoke first on one side, then the other, so that the weight is spread out evenly and the foundation spans are not pulled out of shape.
All these spokes are fashioned from a sturdy nonsticky variety of silk. These are the roadways which she herself will use and she doesn’t want them to be sticky on her feet. When she has to she can oil her feet so that they won’t adhere, but it’s too big a job to keep eight feet oiled all of the time.
The dry spokes won’t catch flies so she turns on the spinnerets which produce sticky silk for the trap. The job—home, trap and all—is done
probably in three or four hours. After a day or two the web may be damaged and Mrs. Spider must start all over again.
If you find a vacant web don’t think it’s abandoned. The owner may have a snug hide-out in a leaf nearby. She’ll be holding in her front legs a “telegraph line” connected with the web. Like an angler she’ll sit there for hours until a tug on her line tells her that a fly has blundered into the net. Then, like a Spitfire, she’ll dash down her private speedway to grab it.
One mystery of nature is how baby spiders can build such geometrically perfect webs without a single lesson from pa or ma. What strange instinct tells one infant to erect a web with 28 spokes while a child of another species puts in 30? Each species usually sticks to a definite number.
The spider’s most highly developed sense is that of touch. Though they have eight eyes, few can see farther than four or five inches. They have no ears but the tiniest gnat striking the web sets up a vibration that the spider detects immediately. And you can’t fool a spider by plucking the web with a straw. She knows the vibration caused by a fly or mosquito.
Common among designs is the “funnel web.” At its bottom the owner lies in ambush. She’d have slim pickings if she relied on flies to alight on its horizontal platform, so she strings a few “trip cords” above. A fly zooms along, smacks into the cord and tailspins into the web below. Ingenious!
Canada’s commonest, the grass spider, is a funnel-web weaver. You can see her sheetlike webs glistening with dew on early mornings around your lawn if the grass is a bit too high.
A Fling at Aviation
Practically all spiders were aviators in their youth. Johnny Spider knows he’ll likely starve if he stays around home. When it’s time to push off, he crawls up to the top of a bush or tall grass stem and spins out a flying machine. This is merely a dangling filament of silk. Air currents waft it upward and outward. Johnny reels out yard after yard. Soon the tug of the breeze on his kite yanks him off his perch. Contact . . . he’s away!
Most flights end after a few rods. Sometimes an updraught keeps him airborne for hours or maybe days. Spiders have parachuted onto ships hundreds of miles at sea.
Man uses the web too, and in parts of the U. S. and Europe spiders raised on “farms” are cared for as tenderly as baby chickens. Though no attempt to weave spider silk into a textile has succeeded, there is a big demand for it in making gun sights, bomb sights, periscopes, microscopes and surveying instruments. They must have their optical fields graduated by fine hairlines on the lens for aiming and measur-
ing. Unless these lines are very minute they will appear under the instrument’s magnification as large as stovepipes. Spider silk is the answer. The black widow’s is ideal. It is very fine, elastic enough to stand up under the recoil oí guns and is not seriously affected by temperature and humidity changes. Most of the torpedoes, bombs and shells of World War II went crashing to their target on courses plotted by a spiderweb scale.
Banana Boy Not Deadly
On black widow farms the operators “milk” their spiders by tickling the spinnerets. Usually the spider twists four strands into a single thread but skilled “milkers” keep the strands separate to obtain a fine product. They reel each strand on a spool or card. A black widow in its lifetime gives about 1,000 feet of silk which during the war was worth $20 per 100 feet.
European instrument technicians who came to Canada during the war at first sent their instruments to England for spider silk. Going to Toronto Island for a swim, one technician discovered a good supply of silk. Thereafter, technicians from Toronto instrument firms made frequent early-morning jaunts to the island where, to the bafflement of residents, they collected the web production of the previous night. Toronto Island spiders made a valuable contribution to Canada’s war effort.
Some spiders such as the trap-door spider of southern U. S., the Methu-. selah of his kind, live in a burrow with a watertight, silken lid. The trap-door spider reaches the ripe age of 12. Most spiders last only a year.
The crab spider lives in a flower and grabs off bees. The big yellowish spider which occasionally arrives in Canada in a shipment of bananas is not a tarantula, but a tropical species of the crab family. Despite sensational stories describing how store clerks risk their lives to kill him, he is no more ferocious than a mosquito.
Canada’s largest spiders are the Dolomedes or water-diving spiders. Common around docks and boathouses of northern lakes, they scamper across the water just as fast as on land. They have been known to catch fish over three inches long. They overpower them in submarine battle, then drag them ashore.
Closely related to the spiders are the daddy longlegs (not spiders because they possess no spinnerets), scorpions, crabs, millepedes and centipedes, and the tiny mites, some species of which are responsible for the mange on dogs and the so-called seven years’ itch of humans. Not a particularly illustrious crowd, but we can’t blame the spider for his relatives.
A colorful race, the spiders. They’ve got everything except a public relations committee.