The strangler fig is the breadbasket of wild foods for wildlife on the islands
Considered by many botanists as one of the most fascinating plants on earth, the strangler fig is also one of the most important plants in Southwest Florida. Worldwide there are more than 900 species of fig trees, with most of these plants occurring in the Australasian region. One species (Ficus bengalensis), native to India, has a trunk that measures more than one-hundred feet in circumference. The century-old banyan fig planted in Ft. Myers on the Edison Estate covers half an acre and is well worth visiting (go to for hours, information and directions).
On the islands, the strangler fig is one of a handful of plants that form the breadbasket of wild foods for wildlife. The small, good-tasting figs that fruit on these trees are eaten by almost everything, be it a flying, crawling or climbing creature. A favorite shelter tree for birds, from warblers to pileated woodpeckers, the niches, twisted trunks, nooks and crannies of the strangler fig also provide habitat for insects, lizards, raccoons, rodents and snakes.
The reproductive cycle of the strangler fig is so bizarre that it demands telling. The strangler fig has a relationship, scientifically referred to as “obligate mutualism,” with a single wasp species known as the gall wasp. As the young seeds form, each and every fig has a tiny hole in it. The entrance is just large enough for a female gall wasp, full of eggs, to squeeze into. As she squeezes through, her delicate wings are torn off and she is unable to leave. She unknowingly deposits the pollen that she has carried with her from another tree and lays her eggs in the stigma of the flowers located within the fig seed.
She then dies and the entrance she came through on seals shut as the fig walls close. After a while, the young male wasps, which develop faster than the females, are born. They then chew open the female eggs and mate with them. After mating, the males chew a hole in the wall of the fig fruit and proceed to die inside the seed. On the way out of the hole opened by the males the winged females are tagged with pollen they will carry on to propagate the next fig tree. Then the females, who are born with delicate wings capable of making a single flight, crawl out of the opening and take off in search of another nearby strangler fig.
If she fails to find a tree before her fragile wings fail, she dies. If she finds another tree, her life cycle is completed once again and the strangler figs fruit are pollinated. It is important to understand that gall wasps are extremely small, only slightly larger than a no-see-um. It’s also believed that this co-dependency has been going strong for sixty-million years and that there are hundreds of different species of wasps matched to hundreds of specific fig species.
As if this unbelievable symbiotic relationship isn’t enough, the story of the strangler fig continues. Once pollinated, these figs ripen and are fed upon by a host of hungry wildlife. The fruits are packed with tiny seeds, many of which are not destroyed with they are consumed, and are passed out in the dung of various animals from the mother tree. In tropical regions fig tree seeds are spread by primates and fruit bats, but on Sanibel and Captiva most of seed dispersion is carried out by birds.
After feeding, a bird might land in a cabbage palm and dispose of its waste. That waste is often trapped in the upward turned bases of the palm fronds, where detritus and standing water allow the tiny seeds to germinate. At this stage in its development the strangler fig survives as an epiphyte, which is the name for a plant that derives all of its moisture and nutrients from the air, rain and debris around it. As this epiphyte matures it sends down long, thin tendrils that eventually reach the soil near the base of the host tree.
With these newfound nutrients feeding it, the strangler fig grows rapidly, as the tendrils twist and grow, eventually wrapping themselves around the trunk of the host tree, which is generally a cabbage palm. Over time the fig grows so large that the cabbage palm no longer receives enough sun to survive and it dies. Eventually the host tree and its root ball decay into nutrients that help to make a mature strangler fig the largest native plant living on Sanibel and Captiva.
There are scores of examples of every stage of this development that can be found throughout the islands. A walk down Island Inn Road will allow you to find an epiphyte fig, a young, sapling fig and a fully mature strangler fig with a dead or dying palm tree hopelessly trapped in its strangling trunk. In one last amazing feat of adaptation, the strangler fig’s limbs are designed with a break-away system that allows them to survive very strong hurricanes. The leaves are the first to let go, with the branches quick to follow.
This system allows the base of the tree to survive and flourish soon after the storm has passed. If the storm is so strong that it takes down the trunk, the root suckers left buried in the soil will regenerate a new sapling. Strangler figs are salt tolerant, making them resistant to storm surges as well.
The strangler fig was used for food by the early Floridians as the small, ripe figs are edible. In Central America, ranchers often use pieces of strangler figs for live fencing. They are also popular as ornamental and bonsai trees. The most impressive aspect of the strangler fig is its ability to adapt, regenerate and survive on these storm-lashed barrier islands.
This is an excerpt from Living Sanibel – A Nature Guide to Sanibel & Captiva Islands by Charles Sobczak. The book is available at all the Island bookstores, Baileys, Jerry’s and your favorite online sites.