One of the Walker Lake orb weavers dangles in front of an informational sign at Sportsman’s
beach. The sign details what little is known about these spiders. (C.W. Wilkinson photo)
If you drive down Highway 95 past Walker Lake, it’s likely you’ll be treated to a number of unique and wonderful views. The lake, stretching to the foot of majestic mountains; a herd of wild horses grazing on the soft green grass; a monolithic rock that looks almost, but not quite, entirely unlike a horny toad.
But if you went in the past few weeks, you would also be treated to (or, perhaps, terrorized by) the sight of thousands of spider webs.
The spiders emerge from their hidey-holes every year and spin intricate webs all over the rocks, picnic tables and highway guard rails along the highway near Walker Lake.
Jeff Knight, the Nevada State entomologist, said the arachnids are orb weavers spiders, from the neoscona genus.
Knight said the genus is fairly large, and all the spider species in it spin similar webs.
Wikipedia says all the spiders in the genus have “characteristic longitudinal groove on the carapace.”
Knight said the spiders weave webs in the classic, “Charlotte’s Web” shape, with several long straight strands to give the web structure and a number of concentric circles. They use the webs to catch flying insects.
While thousands of webs have overtaken Sportsman’s Beach, the spiders don’t pose any threat to anything but bugs, Knight said.
“They’re not one we consider at all an issue or anything,” he said. “If you’re picnicking down there you want to be careful around the tables and that kind of thing, but otherwise they’re eating all the bugs that come off the lake.”
But other than that, Knight can’t say much about the spiders.
He said he can’t figure out which species they are without looking at one of the spider’s mouths under a microscope, and without knowing the species he said he doesn’t know anything about their behavior.
He also isn’t sure what leads to the annual population explosion, but he suspects it’s a combination of want of predators and competition, and lots of food.
“It all depends on the food supply that they have,” Knight said. “Those guys probably wouldn’t eat each other, but they’ll eat anything that flies into the web.”
The spiders seem to be primarily eating a bumper crop of small blue damselflies and gnats, if the contents of their webs are any indication.
Wendy Mazet, University of Nevada, Reno Cooperative Extension master gardener for the western area of Nevada, who also doesn’t know anything specific about the Walker Lake spiders, said the number of spiders and other bugs in Nevada has a lot to do with the numbers of them that survive the winter.
“It all ties back to a lot of mild winters, and just how many can survive, and then nature basically finding the balance to have more predators out there to take care of these other insects,” she said.
The lack of predators at Walker Lake also influences the amount of spiders.
Birds, spiders’ primary predators, don’t appear to be very prevalent on that side of Walker Lake. The few gulls that fly around at the lake (Mazet said they’re not seagulls if they don’t live at the ocean) are likely not enough to control the arachnid hoards.
Wasps, scorpions and assassin bugs will also eat spiders if they can get their chitinous mouth parts on them.
“Ants will take on live or dead,” Mazet said. “If there’s high enough numbers, they’ll take advantage of a spider.”
One favorite theory on why the spiders’ numbers have expanded involved fish.
Because there aren’t any fish in Walker Lake to eat damselfly larvae, they reproduce in astounding numbers (some species of damselfly lay several clutches of thousands of eggs). These flies go on to become food for the Walker Lake clutters (the scientific term for a group of spiders), allowing them to reproduce in the huge numbers we see each year.
Spider mating habits, distressingly enough, involve the male injecting sperm into the female through his swollen mouth parts, Knight said.
It’s impossible to say how many eggs each of the Walker Lake spiders produce in one go, Knight said, without knowing which species the spiders are.
And the plethora of spiders at Walker Lake isn’t the only mass outbreak of critters in Nevada, Mazet said. In some places stink bugs are hatching in spectacular numbers. In some places, people are reporting swarms of hundreds of thousands.
“People just say this march of these insects coming to their house, moving up and over there house, like we do when we’ve had Mormon crickets,” Mazet said.
Thankfully for Mineral County noses, those swarms are, for now, far away from the county Mazet said.
