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Suburban Wild: The arthropod who came in from the cold

Barbara Julien is nature enthusiast who writes monthly about species making their home in Oak Bay
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The holiday season’s over, but some of your winter guests may not have left yet. Spiders slip into the nooks and crannies of houses for warmth, and they’ll thank you for leaving them in peace until spring. They are happy to avoid us, and probably hope (if spiders have hopes) that we’ll do the same for them.

These are eight-legged air-breathing arthropods in the arachnid class (not insects, which have six legs) and there are over 700 species of them in BC. Worldwide, some 45,000 species have been described by biologists, but far more, perhaps up to 120,000 still await discovery and classification. Spiders separated from crab-like ancestors some 380 million years ago, and science has discovered that they’ve been spinning orbs for 136 million years.

The web is the spider’s tool for trapping prey (insects), and its woven intricacy has inspired many mythologies which see the spider as a Great Mother symbol. In indigenous North American mythology Spider was said to have woven the world into existence, and the ancient Egyptians and Babylonians called her the “weaver of destiny”. Her scientific name comes from the Greek princess Arachne, a weaver so skilled that she decided to compete with the goddess Athena. Being a goddess however, Athena won the weaving contest, and then she destroyed her upstart rival’s loom.

The actual spider’s web is still a mystery to upstart science. Its blend of strength and delicacy seems magical. The silk of the webs, made of protein fibre pulled out of specialized glands by the spider’s legs, is five times stronger than is a length of steel with the same diameter. There are between two and eight of these glands which, complete with “ducts” and “spigots” produce the fibre, which loses water and becomes acidic as it’s drawn out, completing a phase transition into a solid. That’s a simplified description of the phenomenon. Suffice it to say that science has not succeeded in replicating in laboratories the proteins involved: the goddess retains her secrets. She lives humbly in our houses and decorates our gardens on dewy mornings with exquisite glistening silver orbs.

However beautiful their webs, spiders themselves are not pretty which is why we not only fear them but project them onto movie screens as images of monsters. But arachnid expert Samantha Vibert of Simon Fraser University writes that spiders are generally non-violent creatures. The few that bite only do so defensively, not aggressively, and few are venomous except to insects. Their insect control activity is in fact crucial for maintaining ecological balance in natural settings. Some catch prey not by weaving webs but by using an equally amazing ability to jump 50 times their own height by instantly pumping blood into their eight legs. Crab spiders can also camouflage themselves by changing colour to match that of flowers they settle on, which helps them evade the birds, wasps and frogs that eat them.

It seems a shame they have to evade us as well, since they mean us no harm and can’t help their craggy bestial looks. Their beetle companions the ladybugs are tolerated in our buildings when they appear for the same reason: to get out of the cold. At them, we don’t scream and wave brooms in horror, so maybe we should aim for a more equitable attitude to Araneae too.