Geneva High grad finds vegetarian spider

Chris Meehan was sweating away in a coastal Mexican forest, failing at an experiment he set up for a course unrelated to his graduate work studying the mating habits of chickadees.

He was observing the symbiotic relationship between ants and acacia trees. The ants, with their potent bites, protect the tree from animals that would eat it. In turn, the tree provides safe housing for the ants and a special high-protein food for them, growths called Beltian bodies, on its leaf tips.

But then, Meehan noticed a third party because it was doing something unusual.

A jumping spider also was eating the Beltian bodies.

That's odd, Meehan thought, because spiders don't eat vegetables. They dine on other creatures.

When Meehan told his professor about it, the prof wouldn't believe it - until he saw it himself.

And that's how a graduate of Geneva High School finds himself a bit of a celebrity, featured in scientific journals and popular press such as National Geographic. He even has a citation in a Wikipedia article.

All over a small arthropod.

The weird spiderThe creature in question is Bagheera kiplingi."Along came this clever little spider. It intercepted - like a pirate - the vegetation," Meehan said.And unlike the ants, B. kiplingi does nothing for the tree."At first he didn't believe me. We both knew it shouldn't happen," Meehan said of his professor - and mentor - Robert Curry, who taught the course tropical biology when Meehan was a graduate student at Villanova.The spider tends to set up housekeeping on older leaves, which the ants don't patrol as much because the nutrients are gone from the Beltian bodies.(Meehan can attest to the ferocity of the ants, having been bitten during the study. He likened it to being stung by a yellow jacket, with the pain lasting several days.)The vegetarianism also is weird because the spiders normally are solitary and aggressively territorial. Yet he observed hundreds living on an acacia tree, getting along.The spiders aren't completely vegetarian. The diet of the Mexican colony he observed was about 80 percent Beltian bodies; the rest was nectar and the occasional ant larvae. A colony in Costa Rica, discovered by another scientist, has a 50 percent vegetarian diet.Mutualism and cooperationThat other scientist, Eric Olson, discovered the spider's veggie diet tendencies in Costa Rica in 2001.B. kiplingi was first identified in 1896, but it appears that everybody else was focused on the ants and trees, and didn't care to figure out what the spider was doing there.Olson and Meehan decided to present their findings together and published "Herbivory in a spider through exploitation of an ant-plant mutualism" in the Oct. 13 issue of Current Biology.It's not just the spiders' cooperation that interests Meehan; he's appreciative of that shown by Olson. "We formed mutualism ourselves," he said. "It is good to see someone open to collaboration."Why vegetarianism?Meehan, 25, has some ideas about why the spiders behave the way that they do and thinks it applies to other species as well."Those Beltian bodies are a year-around supply of food in seasonally dry forests," he said. Access to a steady supply "sort of tames the beast," he added, enabling it to stop being a predator and become more social.Meehan sees more to all of this, of course, than just a weird spider.He is at the University of Arizona pursuing a doctoral degree in biology, specializing in the study of the effect of climate change in the United States and Brazil on species interaction - particularly on what he calls "tropical mutualism."He wants to know why species interact, the evolution of cooperation and conflict. For example, how did some ants become such social species?"Species interactions make the world go 'round," he said.Meehan's curiosity was encouraged by his high school biology teacher, Kevin Gannon.As a middle schooler, Meehan knew that he liked plants, life and gardening. "But I did not know people made a living dissecting nature like this," he said. (Although as a doctoral student, he estimates he is about $40,000 in debt and has no funding to do any follow-up studies on the spiders.)"Mr. Gannon was a really good mentor," he said, giving him a good, fundamental baseline of biological knowledge and encouraging him to pursue independent study projects."It means so much to have someone nurture you."False20001327Chris Meehan, a Geneva High School graduate now pursuing a doctorate in biology, examines acacia trees in a Mexican forest for signs of Bagheera kiplingi, a vegetarian spider, in 2007.Courtesy Robert CurryFalse