Friday, April 20, 2012

Getting the Jump on Jumping Spiders

   In the Spring of 2013, the Sam Noble Oklahoma Museum of Natural History will be having two invertebrate themed exhibitions: one in insects, the other on artwork of Thomas Shahan. Thomas has gotten a lot of attention for his fantastic photographs, and one of his favorite subjects are jumping spiders. Jumping spiders are some of the cutest spiders, and we have several unique and colorful species found here in Oklahoma. Most of his subjects were actually found in the back field of our museum!
    Here is a link to one of my favorite photostreams taken by Thomas on a particularly cute male.
Another shot of a jumping spider by Thomas Shahan

So what exactly are jumping spiders, and why do people take such an interest in them? Well, besides the fact that they are invertebrates and everyone should like spiders, they are one of the largest groups of spiders. They have two distinctive forward-facing eyes that overlap in vision (ALE in figure below), which gives them depth perception and allows them jump to the right location. Try jumping somewhere when you can't see how far away it is!
Where jumping spiders can see with their 8 eyes. Image from Wikipedia

Our eyes also have this ability to judge distances because of the same forward placement on our faces. Hold one eye open and the other closed, look into the distance, and then open both...see how your "depth" changes? The similarity in position of the spider eyes to our eyes is maybe why many of us might find them "cute". Humans tend to like faces that look like ours with big eyes (think kitten pictures, smiley faces, etc.).




All jumping spiders are part of the family Salticidae, which derives from the Latin "salto", or to dance. Many male spiders in this group have elaborate courtship dances, so the name fits! One of the most interesting cases of dancing with males are the peacock jumping spiders. These spiders are from Australia, and the males have multi-colored flaps on the sides of their abdomens that they are able to raise up and wave at drab-colored females to get their attention. Males will even wave their legs around and move side to side, dancing the day away.

Another video of peacock jumping spiders doing their dances
When they aren't dancing, most jumping spiders are out on the prowl looking for small insects and other arthropods for food. Like all spiders, jumping spiders are predatory and feed on other animals. But there has recently been one study that has found a plant-eating jumping spider, Bagheera kiplingi from Central America. These spiders actually eat special bits of plant produced on the leaves of acacia plants. They are the only salad-eaters of the spider world!
Spider eating Acacia bud. From http://dailylinked.blogspot.com/2010/05/5-amazing-spiders-from-around-world.html
Overall jumping spiders are a very diverse and interesting group, and there is a lot to learn about them. So next spring come and see Thomas's show, and learn a little bit more of these fascinating spiders that caught his attention too!

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