Yellow sac spiders ( Cheiracanthium mildei), longbodied cellar spiders ( Pholcus phalangioides) and others share our homes, egg cases can be found on buildings and vegetation, and thinlegged wolf spiders ( Pardosa spp.) may take advantage of a sunny, mild winter day to catch some rays on a stump or log. Yet some spiders can be observed year-round. Some adult spiders do not live past the fall season, while others overwinter under bark, in leaf litter or in other shelters. Early morning dew or frost reveals webs that are nearly invisible at other times. In Ontario, the best time for observing spiders is from late spring to early fall. Spiders differ from insects in having eight rather than six legs, simple rather than compound eyes, two main body parts (abdomen and cephalothorax – a fused head and thorax) instead of three, no antennae and, of course, no wings. Other arachnids include harvestmen (daddy-long-legs), scorpions, ticks and mites. Insects form one class of arthropods, while spiders are an order – a level that is subordinate to a class – of arachnids. Even from this species, a bite is very unlikely to be fatal.īoth insects and spiders are arthropods (invertebrates with jointed legs). In Ontario, however, only the rare and shy northern widow spider ( Lactrodectus variolus) is considered dangerous to people. Most spiders use venom, delivered from an opening in their chelicerae (jaws), to subdue and predigest prey. No other group of animals has been hunting insects so efficiently for so long.Īlthough feared by many, Ontario spiders are generally not dangerous and hardly ever bite humans. The earliest spider fossils date back 300 million years, and the creatures probably developed at least 100 million years before that, during the Devonian period. In turn, they are a food source for many animals, forming an important link in the food chain.Įvolution has equipped spiders with a myriad of techniques for capturing insect prey: jumping spiders leap, crab spiders ambush, wolf spiders give chase and web-weaving spiders entrap. They pursue this role with instinctive dedication some have even moved into the warm micro-climates of people’s homes, unwittingly protecting us from pesky insects. Their ecological role, one that benefits us, is as the ultimate predators of insects. Spiders live among us in almost every conceivable habitat.
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