Marianne Ophardt

Garden Tips: Don’t fear orb weaver spiders

Orb weaver spiders appear larger at the end of the season because the abdomen full of eggs is growing. They may look nasty, but most people have nothing to fear. The spider won’t attack unless it feels threatened.
Orb weaver spiders appear larger at the end of the season because the abdomen full of eggs is growing. They may look nasty, but most people have nothing to fear. The spider won’t attack unless it feels threatened. Tribune News Service

With the Halloween decorations up, it would be hard to miss that folks find spiders scary, along with ghosts, zombies, bats and other creatures. Spiders are portrayed as nasty eight-legged monsters, but they are not that bad.

A couple of weeks ago, a friend expressed her concern about a spider outside my door. I investigated and found a big orb weaver spider spinning a web in the corner of the doorway. I carefully used a broom to relocate this cutey to the garden.

It is not unusual for folks to notice orb weavers at this time of year for two reasons: their webs and their large size. Orb weavers are a family of spiders that spin large orb-shaped webs with concentric rings and radial spokes. The webs are intricate and can be pretty.

They are not aggressive, being more likely to flee than bite, but they will bite in self-defense.

Because orb-weavers are nocturnal, they spin and repair their webs at night, and then settle down in the center to await food. Despite having eight eyes, orb weavers’ eyesight is poor, and they depend on vibrations to let them know when they have captured prey in webs. Insects caught in the web will be injected with a venom that paralyzes, wrapped with silk and carried to the center of the web for eating when the orb weaver is ready.

They sound gruesome, but orb weavers are basically benign to humans. They are not aggressive, being more likely to flee than bite. However, they will bite in self-defense, but the bite reportedly only produces some localized pain, reportedly no greater than a wasp sting.

The other reason we typically notice orb weavers in late summer and early fall is their large size. However, they are not that big much of the year. Most start out the season hatching from eggs produced the previous fall by the females. They carry on their work, spinning webs and eating insects throughout the growing season.

It is not until late in the season, after they mate, that the female’s abdomen becomes enlarged because of eggs. There are types of orb weaver spiders notable for their brightly colored abdomens, oddly shaped bumpy abdomens, or both. Some are called cat-faced, monkey-faced or humpbacked spiders because of the odd spiked shape of their abdomen.

When ready, the female produces an egg sac from her enlarged abdomen. The females and males will die with the arrival of frost, to be survived only by their eggs that will hatch the next spring.

Orb weavers are really nothing to worry about. They are an outdoor spider and most types are never found inside the home, only around the yard and garden. They are also considered beneficial because they eat other insects in the garden.

I was not able to convince my friend, but I hope that I have reassured you that these big scary spiders are nothing to fear.

Marianne C. Ophardt is a horticulturist for Washington State University Benton County Extension.

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