Wednesday, October 14, 2009

First plant-eating spider discovered

Plant-eating-spiderx-large A plant-eating spider? Investigators report the Central American jumping spider feeds on acacia shrubs, making it the first known herbivore among spiders.

In the journal Current Biology, the team led by Christopher Meehan of Villanova University, details how the jumping spider, Bagheera kiplingi, outsmarts ants that live and protect acacia shrubs to prey on the plant's tasty leaf tips. "By circumventing acacia-ant defenses and intercepting ant-acacia rewards, B. kiplingi is the first spider reported to feed primarily and deliberately on plants," says the study.

At sites in both Mexico and Costa Rica, the team reports the spiders feed mainly on the leaf tips used as homes by the ants, which regularly fend off other bugs and plants encroaching on the shrubs, as well as plant nectar. "These spiders occur almost exclusively on ant-occupied acacias, where they breed year-round and generally build their nests at the distal (far) tips of older leaves that have low rates of ant patrol," says the study.

Jumping spider's skills at hunting prey may have enabled the ancestors of the plant-eating species to evolve into ant-evading salad bar fans. "Given that no other spider is known to feed on vegetation, the digestive physiology of B. kiplingi may be specialized to process such a fibrous, nitrogen-poor material. Year-round availability of ant-plant food, combined with indirect defensive benefits possibly conferred by the acacia-ants, may also help explain how the spider’s carnivorous ancestor transitioned to herbivory," the study concludes.

By Dan Vergano
Photo: An adult female Bagheera kiplingi spider defends her nest against acacia-ant worker. (R. L. Curry)


1 comment:

  1. An interesting question "So....does this represent an evolutionary advance for spiders? Or is this a remnant of an older type of spider?"