Critters: Jumping spiders come in a rainbow of colors
Editor’s note: “Critters” is a monthly series featuring insects, spiders, snakes and other freaky/fun creatures found in the Grand Valley. You know, the kinds of critters you aim to keep your distance from but love to learn about. Have a critter you want discussed? Email firstname.lastname@example.org.
Ever see a spider hop, like a surprising, super-powered torpedo launcher? (And, no, we’re not talking about the latest “Spider-Man” movie).
If you answered yes, it was likely one of more than 4,500 varieties of jumping spiders found around the world. These tiny critters come in a rainbow of fuzzy colors, hunt primarily in daylight, and have powerful hind legs to propel them at fast speeds.
“They come in red, orange, yellow, multi-colored,” and sometimes with splashes of blue or green, Colorado State University Extension entomologist Bob Hammon said. Other colors found include the more common brown and black colors, plus hints of copper, gold and silver.
And it’s not strength alone that lends to the athleticism of a jumping spider.
“They can cover distance several times their body length, with rapid changes in hydraulic pressure found in their blood,” Hammon explained. “It’s not muscles; it’s blood pressure.”
From the family Salticidae, Hammon also noted there are likely 25-30 different kinds of jumping spiders living in the Grand Valley. And though appearance varies, all jumping spiders are considered to be powerful hunters, known to eat grasshoppers more than twice their size and even daddy longlegs.
“They’re not going to eat a flying insect in most cases,” Hammon added. “They eat what’s convenient.”
Plus, jumping spiders “hunt sort of like cats hunt,” Denver Museum of Nature & Science Curator of Invertebrate Zoology Paula Cushing, Ph.D., said. “After seeing the movement of insect prey, a spider will swivel its body to face the insect with its large, visually acute front eyes, and then it creeps close to the insect, finally pouncing on it like a cat.”
Being daytime predators also mean salticids “have extraordinarily good eyesight and they can see some colors quite well, which is why some jumping spiders have very bright color patterns on their bodies,” Cushing explained. “Jumping spiders use behavioral signals, crazy hair-like (hair) patches, and color to communicate with each other. This is particularly true of male jumping spiders communicating with their potential lady loves.”
Their eyesight is so extraordinary in fact that “if you see a jumping spider on the side of your house or on your fence and it seems to be watching you, it probably is,” Cushing noted. “At least it sees your movement.”
These critters also use “ballooning,” which is the production of “a silken line to catch winds that carry the spiders,” a “Colorado Arachnids of Interest” info sheet said. “When crawling and hunting, jumping spiders also use silk to produce a dragline that is periodically attached to a solid surface. This allows them to recover if they fall.”
Though people often have deep-seeded, negative emotional responses to spiders, according to Hammon, these arachnids are definitely harmless to people and good to have around.
“They eat a lot of good, bad and indifferent insects and other spiders,” he said. “Spiders are beneficial.”
And though red-colored jumping spiders are often seen throughout Colorado, another common variety to the state is the “bold jumping spider (Phidippus audax),” Cushing said. “It has bright white patterned marks on a black fuzzy body and the front of the (jaws) are fluorescent green.”
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