Ants in your plants

This is a young Myrmecodia tuberosa, a distant relative of coffee that grows as an epiphyte in the forests of Southeast Asia.

Myrmecodia tuberosa

If you know your Greek, you might be wondering if this plant has anything to do with ants. Indeed, it does. This is an example of a myrmecophyte, commonly called an "ant plant" (myrmex "ant" + phyton "plant"). These plants grow in association with ants, with which they have a mutualistic relationship. The plant provides shelter for the ants, who in turn defend the plant from herbivorous pests and furnish it with nutrients from their waste. Where do the ants shelter? In the swollen base, or domatium, which is full of tunnels and chambers.

Cross-section of a Myrmecodia

My favorite ant plants are ferns of the genus Lecanopteris. I have two species, L. sinuosa and L. mirabilis, in my collection. These are two of the easier species and have proven to be quite vigorous and tolerant.

Lecanopteris sinuosa

L. sinuosa has hollow, creeping rhizomes covered in a layer of scales.

Close-up showing scales and a new frond

The hollow rhizomes of L. sinuosa serve the same purpose as the domatia of Myrmecodia spp. by providing shelter for colonies of ants. Most Lecanopteris share this feature, but L. mirabilis is an exception. Its large, flattened rhizomes shield ant colonies from the elements. They remind me of pools of green wax. Here is a small, recent division of L. mirabilis:

Lecanopteris sinuosa

Fortunately, you don't need ants to cultivate these fascinating plants. I grow Myrmecodia and Lecanopteris is sphagnum moss (sometimes sold as "orchid moss"). Regular, weak fertilizer application makes up for the missing ant colonies. Myrmecodia can take very bright light. I've found Lecanopteris to be tolerant of both light shade and more moderate light. Coming from the tropics, they do prefer high humidity.

I hope to add more ant plants to my collection. They're not only beautiful plants, but also great conversation pieces!