Bagheera kiplingi, which is 5-6mm long, is the first-known predominantly vegetarian spider out of some 40,000 arachnids, said the research in journal Current Biology.

The research found the spider eats nutrient-rich structures called Beltian bodies on the tips of Acacia trees, which are packed full of protein.

Professor Robert Curry from Villanova University in the U.S., one of the study’s authors, said there were many reasons why this spider might have abandoned meaty diets.

“They are jumping spiders, so they don’t build a web to catch food, so they have to catch their prey through pursuit. And the Beltian bodies are not moving, … so it is a very predictable food supply.”

The spider’s herbivorous diet was first discovered in Costa Rica in 2001 by Eric Olsen from Brandeis University, and was then observed again in 2007 by Christopher Meehan, at that time an undergraduate student at Villanova University. Then they collaborated to describe the spider for the first time in the recent paper.

A few other spiders have been documented consuming nectar or pollen, but only occasionally. No other spider is so predominantly vegetarian.

The research also found that Bagheera kiplingi males help care for eggs and the young — something entirely unprecedented in the spider world. 

On Xinhua Web site: http://news.xinhuanet.com/english/2009-10/13/content_12221219.htm