Spiders are out and about in Boise. University of Idaho entomologist Ed Bechinski says it's early for Idaho spiders to be out of hibernation (specifically in their case it's known as diapause).
But Bechinski isn’t surprised these arachnids are out. He says southwest Idaho's unseasonably warm temperatures are plenty to tell spiders that spring is here.
Bechinski says the spiders that have spent the winter hiding under your landscaping bark need two things to think it’s spring and wake up. They need an extended period of cold so their bodies know winter has happened, not just a fall cold snap. Then, they just need a few days of spring-like warmth to wake up.
“Maybe in the mid-50s, 55 or so,” Bechinski says. “That wouldn’t necessarily be the air temperature. It would be the temperature the spider experiences along the foundation of the house, you know heat radiating back. So you could have daytime temperatures a little bit chillier than that.”
Bechinski says once a spider becomes active, it starts looking for food and might accidentally wander into a house. He says spiders don’t want to live in homes because there isn’t enough for them to eat.
With some bugs* like flies, an early spring can mean a big population boom by fall because they’ve had extra time to breed. But Bechinski says most Idaho spiders need a year or two of life before they reproduce. So shifting weather patterns shouldn’t have a direct impact on overall numbers.
*using the vernacular for members of the phylum Arthropoda
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