Meet the No-meat Vegetarian Spider

No, thanks, this is one spider that would not like to have flies with that.

When you think of spiders, you’ll most likely conjure up images of webs, and of all manner of insect critter captured therein to serve up spider’s next meal. You’re probably not too likely to picture them saddling up to the salad bar.

But a species of jumping spider native to Central America is indeed a rarity on eight legs. Unlike virtually every other species of spider known to science, the Bagheera kiplingi — named dually for author Rudyard Kipling and for the panther character in his late 19th century novel "Jungle Book" — dines almost entirely on what the local acacia trees serve up.

As recounted to and reported by Scientific American, biologists Christopher Meehan and Eric Olson encountered the unusual creature during a field expedition in Costa Rica in 2001. Meehan rose early one day during the excursion, and a jumping spider caught his attention. Expecting to see it snag an insect, he was amazed to see it pluck a nugget of acacia, scamper away to safe quarters, and proceed to chow down.

Ants in the immediate vicinity were plentiful, a condition that seemed of no consequence to the spider, which was a condition of quite some consequence to Meehan.

Meehan, Olson, and co-authors have published their findings in the journal Current Biology. Investigation into the unusual spider since discovering it led to their finding that B. kiplingli thrives by way of an interdependent relationship they enjoy with the acacia tree and with the ants.

The acacia trees provide the habitat as well as the largest part of their diet in the form of nutrient-rich nodes on the leaves called beltian bodies. The ants fend off most other insects who’d otherwise eat the beltian bodies; and the other contribution the ants make to the spider is that their larvae comprise the remaining minority portion of the spider’s diet. So, while the spiders are therefore not strict vegetarians, the larvae are themselves fed primarily a diet of beltian bodies.

Meehan and team postulate that the beltian body-fattened larvae may be how the spider came to adapt to its primarily plant-based diet.

Photo courtesy of coniferconifer, via Wikimedia Commons