Volume 22 Issue 3, Fall 2017
by Kerry Bzdyk
As I sat down at my computer to begin working on this article, I noticed with some delight that the wallpaper photo on my laptop was indeed a jumping spider, and it has been for years. It’s hard to imagine that in spite of a lifelong fear of spiders, I found this creature charming enough to want to see it so often. But there it is!
Love them or not, spiders are incredibly fascinating and diverse creatures. Salticidae is one of the largest families of spiders, with 5,800 different species making up 13% of all spiders. Within the family there is quite a bit of diversity, but also many common traits. Jumping spiders are generally small, ranging in size from 1/8 inch to 5/8 inch. Like all spiders they have eight legs and two body parts: the abdomen and cephalothorax. They are usually hairy and have stout legs. While they do have spinnerets and can produce webs, they do not build webs to catch prey. They will use silk to create shelter or to make a dragline. They have four pairs of eyes in three rows. The largest pair of eyes faces forward on the front of the distinctively square face, giving these spiders a quite “mammal-like” appearance, which may enhance their charm. But the keen eyesight of the jumping spiders serves a bigger purpose. They are predatory hunters who use their uniquely acute vision to find food. The visual acuity of the jumping spider has been extensively studied. They have the best vision among not only spiders, but possibly all arthropods.
Like all spiders, jumping spiders hatch from eggs and look like miniature adults. The female will attend to her eggs until the spiderlings emerge and disperse. The spiderlings overwinter and mature the following spring, molting as they grow. The average lifespan is one year.
Jumping spiders hunt much like cats do, using their excellent vision to spot prey from a distance and then sneaking up and pouncing on it. They have the ability to jump a distance thirty times the length of their body. Ant Mimic Jumping Spiders (Myrmarachne spp.) are able to imitate ants so well that they can “infiltrate” an ant colony and feed without being noticed. Mimicry, speed, and superior vision give these agile spiders a distinct predatory advantage.
The jumping spider that we most commonly see is the Daring Jumping Spider (Phidippus audax). This is the one we see around our homes, often hunting on windowsills or fences. They are also one of the largest species and can be quite interactive. The next time you encounter one of these little charmers, take a closer look. You may notice them turn around and do the same to you!