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| Adorable jumping spider. picture by Kenneth Gilpin at lookingcloser.net |
But lets start with those big glassy eyes. All eight of them.
The two big ones in front that give jumping spiders their signature look are unique. They give the jumping spider incredibly resolution, beyond the ability of all other spiders and insects, and even as good as some vertebrates [1]. But such accurate vision comes at the cost of a debilitatingly narrow view. The other six eyes give a much wider view, but bad resolution, a poor substitute for catching prey that is just out of the peripheries.
Many vertebrates have a similar problem which they have usually solved by simply moving their eyeballs, but a jumping spiders' lenses are attached directly to the body, they can't move around. So they have evolved one better, moving the retina itself. Like a camera filming through a window, the retina moves inside the lens. This gives the jumping spider peculiar, color changing eyes; when the retina, the darkest part of the eye, is looking away from you, you can almost see through the lens, making it look colorful. And when the eye is completely black, the spider is looking right back at you [2].
Many vertebrates have a similar problem which they have usually solved by simply moving their eyeballs, but a jumping spiders' lenses are attached directly to the body, they can't move around. So they have evolved one better, moving the retina itself. Like a camera filming through a window, the retina moves inside the lens. This gives the jumping spider peculiar, color changing eyes; when the retina, the darkest part of the eye, is looking away from you, you can almost see through the lens, making it look colorful. And when the eye is completely black, the spider is looking right back at you [2].
That vision is especially important for the jumping spiders' signature hunting method: jumping. They are able to jump up to 40x their own length, an ability that would let me jump well over 200 feet (is Spider-Man starting to make a bit more sense now?) [3]. Unlike many other spiders, jumping spiders don't spin webs to catch prey, but actively stalk them on the ground instead [4].
The stalking techniques are incredibly complex. Jumping spiders often do not use a straight line to get to their prey as you might expect, but rather circle around, approaching it from a different angle. The problem is that such a rout can take the prey out of sight, and for many invertebrate hunters, that means out of mind [4]. But jumping spiders seem to go far beyond that, able to choose the best path even when it means they may never see their meal again until they get right-on-top of it [5].
There is more to a jumping spider than just his aggressive side, they are also famed romantics. Male jumping spiders come in a wide variety of bright colors for attracting mates. The peacocks of the arachnid world, jumping spiders come in an astonishing variety of turquoise, maroons, yellows and oranges. The unique coloration can be used to brightly display, or in some cases, deceive [4].
Some species have evolved to become incredible mimics of insects such as ants, beetles and wasps. These disguises help protect them from birds, and other searching predators. Disguises can work both ways however, and some insects have evolved to look like jumping spiders, causing the other-wise hunting spider to back off [4].
But female jumping spiders seem to be particularly picky, and it takes more than just bright colors and disguises to woo them. So males, colors flaring, become tiny flamingo dancers, showing females a variety of dancing moves to show off their prowess. And their dancing repertoire is considerable, including running jumps, body sways and all kinds of leg movements [4]. And to take it one step further, the dance is choreographed to a song all their own.
Jumping spiders may not have ears, but, like Beethoven, they make and hear music by feeling vibrations. Using their abdomen, the males grind away, creating a series of impressive beats while they are dancing. They then put the two separate actions together, making quite the show, all in the name of spider love [1].
Sources:
[1] http://www.youtube.com/watch?v=sMa9FdNM5io
[2] http://www.tolweb.org/accessory/Jumping_Spider_Vision?acc_id=1946
[3] http://www.everythingabout.net/articles/biology/animals/arthropods/arachnids/spiders/jumping_spider/
[4] http://www.peckhamia.com/hosted/Richman%20Jackson%201992%20A%20review%20of%20the%20ethology%20of%20jumping%20spiders.pdf
[5] http://www.sciencedirect.com/science/article/pii/S0003347296903723
There is also sooo much more I wasn't able to cover so please check out:
The stalking techniques are incredibly complex. Jumping spiders often do not use a straight line to get to their prey as you might expect, but rather circle around, approaching it from a different angle. The problem is that such a rout can take the prey out of sight, and for many invertebrate hunters, that means out of mind [4]. But jumping spiders seem to go far beyond that, able to choose the best path even when it means they may never see their meal again until they get right-on-top of it [5].
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| Just some of the bright displays that these spiders exhibit. photo from www.bio.sdsu.edu/pub/spiders/NewFiles/framespg.html |
Some species have evolved to become incredible mimics of insects such as ants, beetles and wasps. These disguises help protect them from birds, and other searching predators. Disguises can work both ways however, and some insects have evolved to look like jumping spiders, causing the other-wise hunting spider to back off [4].
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| No that is not an ant. photo by Wayne Maddison Used form the Tree of Life Web Project |
Jumping spiders may not have ears, but, like Beethoven, they make and hear music by feeling vibrations. Using their abdomen, the males grind away, creating a series of impressive beats while they are dancing. They then put the two separate actions together, making quite the show, all in the name of spider love [1].
Sources:
[1] http://www.youtube.com/watch?v=sMa9FdNM5io
[2] http://www.tolweb.org/accessory/Jumping_Spider_Vision?acc_id=1946
[3] http://www.everythingabout.net/articles/biology/animals/arthropods/arachnids/spiders/jumping_spider/
[4] http://www.peckhamia.com/hosted/Richman%20Jackson%201992%20A%20review%20of%20the%20ethology%20of%20jumping%20spiders.pdf
[5] http://www.sciencedirect.com/science/article/pii/S0003347296903723
There is also sooo much more I wasn't able to cover so please check out:
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