Susan Straight of Chilmark got caught in the same web as Charlotte’s Web author E.B. White. They both had a thing for spiders. “Once you begin watching spiders, you haven’t time for much else,” White wrote.
Spiders have been on Susan’s mind for some time. She shares photos and stories of neighborhood spiders, and has some curiosity about their well-being over the winter and a fascination with their ability to survive through the cold weather.
They do thrive, and with methods and abilities that show an enviable tenacity. As a group, spiders use different approaches to adapt to the change of temperature and decline of food.
Some simply don’t live outside at all. House spiders spend their lives in the cozy and comfy environs of our domiciles. Venturing outdoors is not part of their routines, so putting inside spiders outside can be a death sentence for them even if you have the best intentions. Only a minority, just five per cent of indoor spiders, have ever been outside.
Be thankful for these housemates, since they eat insects that are even more bothersome than they are, including bedbugs, fleas, roaches, book lice, clothes and pantry moths and houseflies.
For the most part, outdoor spiders similarly won’t go into your home; they must rough it to get through the winter. As poikilotherms, the scientific term for cold-blooded organisms, spiders can’t regulate their body temperature and must adapt to the temperatures around them. To take advantage of the sun, spiders may build their webs in an east-west orientation for solar gain. Alternately, to reduce heat they will construct them north-south.
Survival is more complicated than just web position. Spiders must avoid freezing and protect themselves, their eggs, and their offspring in order to make it until spring. These eight-legged wonders don’t migrate, but can overwinter or even remain active depending on species and conditions.
Spiders need time to adjust to the change in season. Before the cold, wintry weather sets in, they go through a hardening process. Over a few days, a spider’s body will produce a glycol and protein compound known as polyhydroxy alcohol in their hemolymph (blood) which acts as a cellular antifreeze. With this superpower, some spiders can even survive temperatures down to negative four degrees Fahrenheit.
Dormancy, or diapause, is a hibernation-like state that describes the majority of spider species winter condition. As food supply is low, during diapause spiders’ metabolism slows, and they must seek shelter from other predators and weather to keep their body temperature above freezing.
About 85 per cent of spiders are dormant over the winter, but others can remain active. Consider those in the Linyphiidae family which survive by eating springtails, those black jumping insects that you sometimes see on snow. Another strategy for winter spider survival is to live in the area above the ground and below the snow in the subnivean zone. Subnivean spiders find food and warmth in their microclime.
To safeguard eggs and young, some spiders weave silken sacs for their eggs and newly hatched spiderlings. These sacs are often stashed in protected places, under the leaf litter, behind bark, or even on the female spider herself, who personally takes responsibility for keeping them in a warm, protected location.
Then there are the spiders like Charlotte who simply can’t survive the winter and only live for a single season. Whichever species you contemplate, you will likely end up agreeing with Susan Straight and a character from Charlotte’s Web, who upon seeing a spider in the pig barn exclaimed: “We have no ordinary spider.”
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