Your intrepid blog host contemplating the devil's work (Jatun Sacha, Ecuador)

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.

Myrmelachista inhabits the hollow, swollen domatia of Clidemia

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.

Clidemia growing in the Devil's Garden. This particular patch was composed of two plant species (the other is a Tococa, in background), both inhabited by the same ant colony.

A hollow Tococa stem in the garden holds ants, ant brood, and mealybugs that the ants tend for honeydew.

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.

Myrmelachista and mealybugs in a Tococa plant.

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.

This devil's garden Tococa has a swollen leaf base for housing the ants

More photos here.


Sources:

*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.