31 October 2011

What does it mean to be a jumping spider?

Have you ever wondered what it means to be a jumping spider?  If you're like most people, then the answer is very likely no.  If, however, you are one of those rare souls who have pondered such a point, then I say good for you!  Either way, today's post will focus on jumping spiders and what makes them so special as a family of spiders.

First and foremost, as with many rules in science there are exceptions. Today, however, we will stick to the traits common to most jumping spiders.

Jumping spiders are unique in several ways, but our focus will be on the three biggest differences that set them apart from other spiders. These differences are:
  1. No webs
  2. Excellent vision
  3. Very smart
No webs
Unlike most other spiders, jumping spiders do not spin webs for prey capture, but rather hunt them like miniature, eight-legged cats.  They do still produce silk, and it is used in hunting, but not for prey capture.  Rather, they use the silk as a safety line, similar to a rock climber's rope.

Dragline and attachment point on glass. (Frank's Photo Essays)
The dragline ensures that when they jump, either after a prey item or to cross a gap, they have a backup if they miss.  Salticids also use silk to make retreats (the spider equivalent of a sleeping bag)
and for egg sacs, which are usually deposited in the females retreat.