Tuesday, February 13, 2007

Things Are Not Always What They Seem To Be

Waiting inconspicuously for a meal is a simple and effective feeding strategy, but it does have limitations. A slight movement can reveal the hunter's presence and alert the prey. Some spiders adopt a rather different approach: they mimic not the background, but another creature. One species of jumping spider that mixes with soldier ants has fang-like chelicerae, or biting tools, that resemble ants' jaws. Other tropical spiders have false eye spots on the front or rear, making them resemble ants.

It was once thought that these adaptations allowed spiders to get near ants and feed on them, but in fact ants are only a small part of their diet. The real advantage seems to be that the disguise protects them from birds and helps them to get near small flies less likely to fear ants than spiders.

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