Ben Crair, August 10, 2020
The produce section of the grocery store is a botanical disaster. Most people know that a tomato is technically a fruit, but so is an eggplant, a cucumber, and a spaghetti squash. A banana, which grows from a flower with a single ovary, is actually a berry, while a strawberry, which grows from a flower with several ovaries, isn’t a berry at all but an aggregate fruit. The most confusing classification, though, will start showing up on American shelves this month. Shoppers will find mission figs with the grapes, kiwis, and other fruit, but a clever botanist would sell them at the florist, with the fresh-cut roses. Although many people dismiss figs as a geriatric delicacy or the sticky stuff inside bad cookies, they are, in fact, something awesome: enclosed flowers that bloom modestly inward, unlike the flamboyant showoffs on other plants. Bite a fig in half and you’ll discover a core of tiny blossoms.
All kinds of critters, not only humans, frequent fig trees, but the plants owe their existence to what may be evolution’s most intimate partnership between two species. Because a fig is actually a ball of flowers, it requires pollination to reproduce, but, because the flowers are sealed, not just any bug can crawl inside.* That task belongs to a minuscule insect known as the fig wasp, whose life cycle is intertwined with the fig’s. Mother wasps lay their eggs in an unripe fig. After their offspring hatch and mature, the males mate and then chew a tunnel to the surface, dying when their task is complete. The females follow and take flight, riding the winds until they smell another fig tree. (One species of wasp, in Africa, travels ten times farther than any other known pollinator.) When the insects discover the right specimen, they go inside and deposit the pollen from their birthplace. Then the females lay new eggs, and the cycle begins again. For the wasp mother, however, devotion to the fig plant soon turns tragic. A fig’s entranceway is booby-trapped to destroy her wings, so that she can never visit another plant. When you eat a dried fig, you’re probably chewing fig-wasp mummies, too.
The fig and the fig wasp are a superlative example of what biologists call codependent evolution. The plants and insects have been growing old together for more than sixty million years. Almost every species of fig plant—more than seven hundred and fifty in total—has its own species of wasp, although some commercial fig production favors varieties that do not require pollination. (They are grown from cuttings and produce fruit without any seeds.) But codependence hasn’t made the fig and the fig wasp weak, like it can with humans. The figs and fig wasps’ pollination system is extremely efficient compared with that of other plants, some of which just trust the wind to blow their pollen where it needs to go. And the figs’ specialized flowers, far from isolating them in an evolutionary niche, have allowed them to radiate throughout the natural world. Fig plants can be shrubs, vines, or trees. Strangler figs sprout in the branches of another tree, drop their roots to the forest floor, and slowly envelop their host. The branches of a large strangler fig can stretch over acres and produce a million figs in one flowering. Figs themselves can be brown, red, white, orange, yellow, or green. (Wild figs are not as sweet as the plump and purple mission figs you buy at the farmers’ market.) And their seeds sprout where other plants’ would flounder: rooftops, cliff sides, volcanic islands. The fig genus, Ficus, is the most varied one in the tropics. It also routinely shows up in the greenhouse and the garden.
The variety and adaptability of fig plants make them a favorite foodstuff among animals. In 2001, a team of researchers published a review of the scientific literature and found records of fig consumption for nearly thirteen hundred bird and mammal species. One of the researchers, Mike Shanahan—a rain-forest ecologist and the author of a forthcoming book about figs, “Gods, Wasps, and Stranglers”—had spent time studying Malaysian fig trees as a Ph.D. candidate, in 1997. He would sometimes lie beneath a huge strangler fig and record its visitors, returning repeatedly for several days. “I would typically see twenty-five to thirty different species,” Shanahan told me. “The animals would include lots of different squirrel species and some curious creatures called tree shrews. There would be some monkeys and a whole range of different bird species, from tiny little flowerpeckers up to the hornbills, which are the biggest fruit-eating birds in Asia.” There were also pigeons, fruit doves, fairy bluebirds, barbets, and parrots. As the biologist Daniel Janzen put it in “How to Be a Fig,” an article from 1979, “Who eats figs? Everybody.”
With good reason, too. Figs are high in calcium, easy to chew and digest, and, unlike plants that fruit seasonally, can be found year-round. This is the fig plant’s accommodation of the fig wasp. A fig wasp departs a ripe fig to find an unripe fig, which means that there must always be figs at different stages. As a result, an animal can usually fall back on a fig when a mango or a lychee is not in season. Sometimes figs are the only things between an animal and starvation. According to a 2003 study of Uganda’s Budongo Forest, for instance, figs are the sole source of fruit for chimpanzees at certain times of year. Our pre-human ancestors probably filled up on figs, too. The plants are what is known as a keystone species: yank them from the jungle and the whole ecosystem would collapse.
Figs’ popularity means they can play a central role in bringing deforested land back to life. The plants grow quickly in inhospitable places and, thanks to the endurance of the fig wasps, can survive at low densities. And the animals they attract will, to put it politely, deposit nearby the seeds of other fruits they’ve eaten, thereby introducing a healthy variety of new plants. Nigel Tucker, a restoration ecologist in Australia, has recommended that ten per cent of new plants in tropical-reforestation projects be fig seedlings. Rhett Harrison, a former fig biologist, told me that the ratio could be even higher. “My inclination is that we should be going to some of these places and just planting a few figs,” he said.
Fig trees are also sometimes the only trees left standing from former forests. In parts of India, for instance, they are considered holy, and farmers are reluctant to chop them down. “Diverse cultures developed taboos against felling fig trees,” Shanahan told me. “They said they were homes to gods and spirits, and made them places of prayer and symbols of their society.” You can’t really taste the fig’s spiritual aura in a Fig Newton, but it shines in the mythologies of world religions. Buddha found enlightenment under a fig tree, and the Egyptian pharaohs built wooden sarcophagi from Ficus sycomorus. An apple tree might have cost Adam and Eve their innocence, but a fig tree, whose leaves they used to cover their nudity, gave them back some dignity. If only they had preferred figs in the first place, we might all still live in Eden.
*This article has been revised to clarify the fact that not all fig plants require pollination to produce edible fruit.