Our eight-legged friends

By Allison Holzer, Interpretive Naturalist, Kroening Interpretive Center

There are many animals that we associate with the coming of autumn: deer, turkeys, squirrels…..but my favorite are the spiders. Not only are spiders a mainstay of Halloween creepiness, but this season is the best for finding and observing large spiders in the woods and prairies.

All spiders have eight legs (unless they are unlucky enough to lose one), but not everything with eight legs is a spider: ticks, scorpions, mites and daddy-long-legs all have eight legs, but are not spiders. What sets spiders apart? All spiders have two main body parts–fangs that can inject venom and spinnerets that spin silk.

Spiders can be as small as a poppy seed or as large as a sheet of paper, but here in Minnesota our largest spiders are, appropriately enough, fishing spiders. These large ambush predators can have a leg-span as long as a driver’s license, but are quite harmless to people. Other large spiders we see in the fall are garden orb-weavers, which sit motionless like shiny yellow coins in their large webs, and furrow spiders, which create webs under eaves and around outdoor lights. These spiders rid us of incredible numbers of insects each day, and are best left alone to do their work.

Many of the spiders that we see in the fall have actually been around and active since spring or summer, starting out as small spiderlings and eventually growing into the large adults that we see now. If there is no hard frost, they will continue to eat and grow, eventually laying eggs in a silk egg sac and then dying by the end of the season. The exception to this generalization are those spiders that live in human dwellings—house spiders, cellar spiders and a few other species live indoors and are active year-round, feeding on any insects that find their way into the buildings in which they live.

People tend to have an uneasy, if not outright combative, relationship with spiders. Spiders are usually unwelcome guests in our homes, and are unceremoniously swatted, vacuumed up or removed to the outdoors. Having a spider in your house, however, can be a downright useful situation: all spiders in Minnesota are predators, eating either insects or other spiders. That means that any spider you see indoors is eating insects in your home—perhaps as many as 2,000 flies, mosquitoes, moths, ladybugs and so on each year!

Your in-home insect control will also eat other spiders and centipedes and will generally stay away from (and are harmless to) people and pets. In fact, there are no spiders commonly found in Minnesota that are remotely harmful to people. So the next time you find a spider in your house, consider its benefits to your household and whether it is better left where it is.

Join us for the following nature programs. Reservations required, call 763-559-6700. River Walk, Saturday, Oct. 3, 9-10 a.m., all ages, free, no registration required. Big River, Small Fry: Nature for Curious Kids, Thursday, Oct. 8, 9 a.m.-noon., ages birth-5 with an adult, $5/person, ages 1 and under free. Pumpkin Boats, Saturday, Oct. 24, 10 a.m.-noon., all ages, $6/person. River Puppets Trick or Treat, Tuesday, Oct. 30, 10-11:30 a.m., ages 2-6 with an adult, $4/person.

Free Family Fundays: Come by on Sunday afternoons anytime between 1-3 p.m. for a free family program: Snakes, Oct. 4; A Squirrely Adventure, Oct. 11; Digital River Scavenger Hunt, Oct. 18; and River Rock Monsters, Oct. 25. Reservations not required. Call us at 763-694-7693 for info or visit Threeriversparks.org.