EPOW - Ecology Picture of the Week

A Tree, an Ant: Umbrella in the Canopy

Cecropia (Cecropia sp.), Family Cecropiaceae (prev. Moraceae)
La Selva, Costa Rica

Explanation:  When a large tree falls in the tropical rainforests of Central America, it creates a big gap in the forest canopy.  Nearly instantly, many plants are suddenly bathed in rich sunlight and begin the race to fill the gap.  Here is one winner of this race:  the cecropia tree.

In one sense, cecropias are weeds, in that they inhabit disturbed sites, including natural and human-made forest clearings.  But they are also native to neotropical forests and are weeds with a difference.  

Cecropia trees produce long green fruits that are sought by fruit-eating bats, birds, and other wildlife, who eat the fruits and disperse the seeds through the forest.   

But more interesting, their milky sap attract ants.  The tree is what is called a myrmecophyte in that it has a symbiotic relationship with ants, particularly Azteca ants.  The stems are hollow, providing the ants with shelter; the ants in turn swarm to defend the tree from herbivores and from other overshadowing vegetation.   Cecropias actually produce glycogen as food for the ants, from small white Mullerian bodies on the leaves.  Tree and ant: this is truly a co-adapted symbiotic pair.  

According to one resource, Honduran farmers use Cecropia peltata to aid animals during birthing by speeding up labor, and the leaves contain extracts useful to fight gonorrhea.  Other uses of cecropia trees reportedly include treatment of asthma, dysentery, liver ailments, warts, dropsy, flu, and other ills.