There are approximately 40,000 species of spiders in the world, all of which have been thought to be strict predators that feed on insects or other animals. Now, scientists have found that a small Central American jumping spider has a uniquely different diet: the species Bagheera kiplingi feeds predominantly on plant food.
The research, led by Christopher Meehan of Villanova University and Eric Olson of Brandeis University, has revealed the extraordinary ecology and behavior in Bagheera kiplingi, which lives throughout much of Central America and southern Mexico. There, the spider inhabits several species of acacia shrubs involved in a co-evolutionary mutualism with certain ants that has long been a staple of ecology textbooks: the ants fiercely guard the plants against most would-be herbivores, while the acacias provide both housing for the ants via swollen, hollow spines and food in the form of nectar (excreted from glands at the base of each leaf) and specialized leaf tips known as Beltian bodies. The Bagheera spiders are “cheaters” in the ant-acacia system, stealing and eating both nectar and—most remarkably—Beltian bodies without helping to defend the plant. The spiders get the job done through active avoidance of patrolling acacia-ants, relying on excellent eyesight, agility, and cognitive skills.
How do the spiders get around the ants that are supposed to be guarding the acacias and gobbling up the Beltian bodies themselves?