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Vegetarian Spiders

October 27, 2009

A population of spiders in Mexico subsists almost entirely on plants.


Leaf-hunting spiders. I’m Bob Hirshon and this is Science Update.

A Central American jumping spider, known as Bagheera kiplingi, is the first known spider to eat mostly plants. Their veggie of choice: acacia leaf tips, guarded by venomous ants that live on their nectar. Biologist Christopher Meehan, formerly of Villanova University, says the spiders case out the shrub first.

CHRISTOPHER MEEHAN (Villanova University/University of Arizona):
And at some point they just decide to go in for the kill. And they use these incredibly entertaining acrobatics to literally just steal a vegetable from under the noses of the ants.

Meehan says the leaf tips keep the spiders well-fed — even in the dry season, when insect prey would be scarce. Plus, the ants fight off all the competition. However, he says not all Bagheera spiders are equally herbivorous: while a Mexican population subsists on 90 percent acacia leaves, their Costa Rican cousins split meat and veggies 50-50. I’m Bob Hirshon for AAAS, the Science Society.