I had been following an army ant raid for half an hour through dense tropical forest when the trees unexpectedly parted to reveal a small clearing. Sun broke through the canopy and fell on a low tangle of furry plants. It was a monoculture, looking as though planted by a reclusive sort of gardener.
I had stumbled into a Devil’s Garden.
Local lore holds that malevolent forest spirits create these unnatural crop circles, but the truth is just as weird. Devil’s Gardens are made by ants.
The plant species that compose these gardens- mostly in the genera Tococa, Clidemia, and Duroia- sport swollen structures filled by the nests of tiny Myrmelachista ants* no more than 3 millimeters long. The ants are meticulous about caring for their hosts, removing pesty herbivores and injecting formic acid into the saplings of competing plants.
Over time, the systematic removal of non-host species leads to a dense garden composed of nothing but the ant-plants. As the ant colonies are spawned by thousands of continually replaced queens, the gardens are potentially immortal. One Duroia garden in Peru was recently estimated to be 800 years old.
I had never seen a Devil’s Garden. Finding this one was one of these delightful surprises of tropical ecology- what a treat! I abandoned my planned photo session with the army ants to spend an afternoon shooting the furry little ant plants and their quirky ant partners.
More photos here.
- Frederickson, M. E., Greene, M. J., Gordon, D. M. 2005. Ecology: ‘Devil’s gardens’ bedevilled by ants. Nature 437: 495-496.
- Renner, S.S., and Ricklefs, R. E. 1998. Herbicidal Activity of Domatia-Inhabiting Ants in Patches of Tococa guianensis and Clidemia heterophylla. Biotropica 30: 324-327.
*Myrmelachista is an extraordinarily poorly known group of ants. Most species are probably undescribed. Given their ecologically fascinating habits, though, big discoveries certainly await those with the patience to work with these small insects.