This segment of The Old Farmer’s Almanac Garden Musings podcast series was written by George and Becky Lohmiller and is read by Heidi Stonehill, an Almanac editor.
Those Itsy Bitsy Spiders
More than 30,000 species of spiders have been discovered so far. Most of them are itsy bitsy indeed, some smaller than the head of a pin, but there are big ones, too. Certain tarantulas found in tropical South America have a five-inch-long body with a leg span of ten inches and often dine on frogs and small lizards.
Although spiders are feared by many, they almost never bite unless disturbed, and very few are poisonous to humans. In fact, spiders are garden heroes that kill more insects than any other creature on Earth. Spiders are not insects but instead belong to a class known as arachnids, which includes ticks and mites, and are distant cousins of scorpions and crabs.
The majority of spiders are web builders that trap their prey in silken snares. The silk is produced in glands in the spider’s abdomen and discharged through spinning tubes in long liquid strands that harden when they come in contact with the air.
Even though web-building spiders have eight eyes, they have poor eyesight and locate their victims through vibrations in the web. When an insect becomes tangled in the sticky trap, the spider binds it in strands of silk. Then it literally sucks the life out of its prey’s body, leaving just the hard shell. Oil secreted by the spider keeps it from becoming trapped in its own web.
Not all spiders build webs. Some hunt in plants or on the ground. The wolf spider is equipped with keen vision and powerful legs for running down its prey; it then kills the victim with quick stabs from its venomous fangs.
The trap-door spider lives in a burrow lined with silk and covered with a round silken lid. When the spider feels the vibrations of an approaching insect, it springs from its hiding place and pulls its victim underground.
As ferocious as spiders are to other bugs, they are quite vulnerable; they are attacked by wasps, birds, frogs, and even other spiders, and are highly sensitive to pesticides. Considering the quantities of harmful insects that they eat, perhaps we should hold off on spraying our gardens and give the spiders a chance to solve our pest problems.