August, 2004

Bold Jumping Spider

This cute hairy little face might not look menacing in the photo, but in real life the bold jumping spider (Phidippus audax), also called the daring jumping spider, lives up to its name. Anyone familiar with jumping spiders has probably marveled at their perceptual abilities, which include watching and reacting to us as if a tiny spider and a medium sized mammal are on the same scale. Although most jumping spiders are 1/8 to 1/4 inch long, the bold jumping spider females are often over 1/2 inch in length (the males are slightly smaller). Before I discovered its real name, descriptive terms like huge, monstrous, big, black, and hairy all came to mind. Common throughout the eastern half of the U.S., this spider is not easy to overlook.

Currently we have a large female bold jumper living in a back corner of our yard. I've seen her out hunting and have also discovered her hiding place. The comparison to a leopard and its lair is apt. Although such a big and powerful spider is imposing to some creatures, it is also a tender morsel for larger predators, such as birds. Hence, the spider must both hunt and be wary at the same time. Because I am larger than the spider, she is very uneasy when I'm around. If possible, she will quickly retreat to her safe haven, which is a silk-lined "nest" in a rolled up leaf on a ginger plant. If she is farther away, she may hide or, if I seem benign at the moment, she may continue to hunt. She has occasionally tried to scare me away, moving towards me and taking a stand as if ready to leap. Since jumping spiders can cover a lot of distance, I take these threats seriously and back off. The larger jumping spiders can easily bite through our flesh with their fangs and, although they are not dangerously poisonous, the venom does hurt. If I use a stick to poke towards the spider, she will sometimes grapple with it and attempt to bite it.

One of the strangest things this spider has done was to suddenly lift her abdomen into the air and let silk flow out. I then realized that I was downwind in a very slight breeze and the silk came right towards me. At first I didn't move as it touched my arm, but then I thought that she might be able to crawl on the line over to me (highly unlikely considering her size and weight, but I was not calm and rational at the moment). I gently pushed the web away and the spider, as though she had just gathered what information she needed from her probe, quickly scooted under a leaf and hid. I was relieved.

Bold jumping spiders are often found in gardens and near houses, where they are helpful in the control of unwanted insects. Unfortunately, they tend to also enter houses, where their size and hairiness usually cause a great deal of alarm. Victims of their appearance and instinctive aggressiveness, these large jumping spiders are easily crushed with a fly swatter, frequently wielded in panic.