The Atala Butterfly and the Coontie Plant: A Mutualistic Relationship

July 12, 2022

By Melinda Schuman | Conservancy Biologist

The coontie (Zamia integrifolia) is the only native North American cycad and we are fortunate to have it growing in southwest Florida.

Cycads belong to the group of plants called gymnosperms which means “naked seed” because the seeds are exposed and fertilized in open-air. They are often referred to as “living fossils” because they have changed very little since they dominated the landscape millions of years ago. Each coontie plant is either male or female and produce cones for reproduction. Much can be learned about this unique, slow-growing species and some beautiful specimens can be found on Conservancy’s campus. 

Female cone
Male cone
Female with exposed seeds

Coontie plants contain the toxin, cycasin, however, when this toxin is removed through a process of powdering, soaking and repeated rinsing, they can become a source of edible starch. This usefulness, learned by early Florida settlers from the local Native American technique, resulted in its near demise due to overharvesting. 

The extirpation (loss of a native plant or animal in a specific area as opposed to the entire population) of Florida coonties, especially on the east coast, consequently devastated the population of the atala butterfly (Eumaeus atala) population, which depended upon it as its sole larval host plant.

As a result, this stunning little butterfly was once feared to be extinct in Florida! 

Atala butterfly
Atala butterfly

The coontie and atala have what is known as a mutualistic relationship – when two unique species “work together” and each benefits.

The larvae (caterpillars) of this unique little butterfly feeds on the leaves of the coontie and are not only able to survive ingesting the toxins, but it also makes their own bodies toxic and unpalatable to many predators. This toxicity warning is displayed by their bright coloration in both larval and adult life stages.

In return, the droppings of the atala help fertilize the soil. The caterpillars are so insatiable that sometimes they devour the coontie plants to the ground, where the plants appear dead to most observers. However, under most circumstances, this damage is only temporary. The coontie recovers, grows fresh new leaves, and the process starts again.

Fortunately, coontie populations have slowly rebounded as we preserved our native pinelands, and with them, the atala butterflies rebounded as well – some would even declare them as “pests”. Historically, the atala butterfly may not have occurred in southwest Florida, with their populations mainly flourishing on the southeast region and surrounding Caribbean islands. The range expansion to southwest Florida is likely the result of being transported over, on purpose or accidently with landscape plants.

However, the near demise of these two species followed by their impressive comeback shows the interconnectedness of the inhabitants of our unique environments here in Florida.

Hopefully we can better understand the importance of maintaining natural habitats and planting native species in our yards for the benefit of the environment and all the species that depend on them. 

For more information on the atala butterfly at the Conservancy, please visit Susan Snyder’s website.

There are many atala butterflies on our campus at the Conservancy of Southwest Florida. Come visit us to see the many butterflies on our trails and learn more about how important it is to plant native.