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Eating Invisible Flowers: the Delicious Mystery of FIGS

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© Keith Irwin

Their skins are golden or leaf green, delicate cream with a pale pink blush, amber, mauve, royal purple shading into eau de nil, or inky violet tinged with midnight. There are dozens of varieties in Portugal, and their names echo like the words of a song – surely a love song in praise of the beloved’s beauties: Olho de Perdiz, Douro, Pingo de Mel, Paraíso and Princesa.

Every year, millions of people around the world watch the figs swell and bend their necks in eager anticipation of that moment of peak ripeness when they can sink their teeth into sticky, succulent, intense pleasure. No matter how many times over the decades we have plucked a sun-warmed fruit, or split it with our fingers to expose its rosy treasure, somehow, it always feels like the very first time.

Long, long ago, wandering tribes in western Asia and the Middle East decided that wherever the fig tree grew was a very good place to pitch their tents. With its breba crop springing from last year’s wood to mature in spring, and its main crop on new branches burgeoning from August to November, the tree was like a mother to them. Carrying satchels or pots of sun-dried figs, they could travel anywhere and feed both man and beast – cattle, donkeys, even dogs – through the leanest times. But why travel at all? Perhaps it was Ficus carica, the edible fig, that first convinced nomads to settle and become farmers. Nine fossils from the Jordan Valley dating to about 9400 B.C. prove that ficus was one of the earliest plants to be cultivated by man – amazingly, more than 1000 years before wheat or rye.

And still, we adore them. A fig is edible perfection. Little wonder the Prophet Muhammed told his followers, “If a fruit ever descended from Paradise, I would say this is it.”

We in Portugal are blessed with a plethora of figs; but how much do we really know about this heavenly plant? For example, have you ever gazed at a fig tree from a distance and admired its blossoms? No? Well, never mind. Nor has anyone else on earth. Long ago, some observant Oriental gave this large-leaved member of the mulberry family its Chinese name – “wú hu? gu?” – which means: “fruit without flowers”.

Since we see figs develop in abundance each year, yet never a hint of perfumed petals or buzzing bees, that name seems apt. Yet it is quite wrong, as I discovered when I started to do a little research. And then the excitement of the story carried me away. There is everything in the tale of the humble fig: fascinating science; history and geology on a vast scale; religion and mystery. Are you sitting comfortably? Then I’ll begin.

For a start, though I had never realized it, Ficus carica does bear flowers. If you’ve ever sunk your teeth into a sweet, seedy, luscious fruit, you have actually munched through hundreds of its tiny florets. Slice open the flask-shaped syconium of a ripe fig and look closely at what lies within.

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Inside, a fig is packed with slim florets; each can produce a seed.

© Keith Irwin

Tease out the individual ‘threads’ you see with a toothpick. These are its flowers – all female, within a complex cluster biologists term an “inflorescence”. Once fertilized, each floret carries on its tip a single seed. Taken as a whole, the mature, juicy pod of yumminess encloses a complex “infructescence”. In other words, your fig is not a fruit in the simple sense, but a plump, perfectly-packaged bundle of edible flowers.

But why the devil are these flowers hidden inside? Clearly, pollinating honeybees can’t get to them. So…how do they manage to turn into this sumptuous, super-healthy treat?

Sex, Death and Continental Drift

To begin to find an answer, we have to whoosh back in time, almost half a billion years. According to genome sequencing data, scientists calculate that this was the eon when terrestrial plants appeared. Around the same era, a daring group of crustaceans abandoned their watery homes for the land, and evolved into creepy-crawly insects. Fast-forward to about 300 million years ago, when some of their descendants, such as dragonflies, began to sport wings. They weren’t pollinators, because plants still didn’t have flowers; however, their ‘upwardly mobile’ abilities allowed them to hunt prey or plunder plant goodies even in the canopies of the tallest trees, far away from their pedestrian relatives.

Then, around 250 million years ago in the Permian period, catastrophe struck: mass extinctions – the worst ever seen on earth. They wiped out 83 percent of all genera. Even so, enough survived to evolve new and amazing life forms. Among them, plants with pollen and nectar-bearing flowers (known as Angiosperms) that develop seeds within their ovaries, made their first appearance; according to the fossil record, this occurred about 160 million years ago. Shortly afterwards (in evolutionary terms), Hymenoptera – insects including wasps, bees and ants capable of pollinating their flowers arrived – a fine example of what boffins term “co-evolution”. Voila – the sexual imperative to procreate now had a new cast of players capable of improving one another’s chances in the big survival challenge called Life.

Later, in the Jurassic – better known as the “age of dinosaurs”, the vast southern landmass called Gondwana started to split, setting adrift continents that would eventually emerge in the shapes and positions we know today. South America, Antarctica and Australia slowly lumbered away from Africa. The Atlantic Ocean yawned wider. Some plants and animals that had evolved on one side of it gently emigrated en masse to the other, and adapted to new conditions as they went.

By now, we’re in the Cretaceous period, 145-66 million years ago, a time of incredible ecological diversification. And, at last, between 60-80 million years ago, the two heroes of our story finally took centre stage – hurrah! They were about to form an extraordinary partnership of mutual assistance that continues undiminished into our own time.

The first partner was what we might call Proto-fig; the other was an eentsy-weentsy Proto-gall wasp that could easily have passed through the eye of a needle, had such things existed. She was heavy with eggs and urgently needed somewhere to lay them that would provide sustenance when her brood hatched. The laden Proto-fig tree beckoned.

Her kind must have tried and failed over and over to gain entrance to a swollen synconium through the eye-like ostiole on its base. The belly of a fig was, after all, an ideal birth chamber for wasp young.

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Non-pollinating wasps feeding on South African Cape fig. (Public domain)

On this day, however, the special day that changed the course of Figgy History, our wasp was uncommonly lucky. Perhaps other wasps or ants – simply after a good meal, had munched their way into the ostiole ahead of her arrival, making her passage a little easier. In any case, the minute Proto-wasp succeeded in pushing and shoving her way into the lovely, soft interior and laid her eggs. However, her frail wings were shredded. She could never leave; the hatchlings’ nursery became her tomb. Exhausted, she died, and her corpse was dissolved by enzymes inside the fig.

The Next Generations

We cannot know exactly how long it took for the Blastophaga psenes wasp to evolve a set of behaviours and physiological characteristics that exactly suited both its own purposes and those of the fig trees. But ultimately, what happened – and continues to happen today for all the fig types that require pollination (see bullet points below this article) is this: when the eggs hatch, wingless males emerge first. They chew open the egg capsules of the opposite sex, and, while the females are still inside, they mate with as many as possible. If you look at the illustration, you will see how well-endowed these boys are. Then they use their powerful jaws to chew a way out through the fig’s ostiole, thus providing an easily exit for the winged females. That done, the males die.

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Female and wingless male Blastophaga psenes wasps. (Public domain)

Next, the fertilized females squeeze out of the tunnel, dusted liberally with pollen from their birth-fig. Once their wings are dry, they head off to find another fig of the right type in an optimum stage of development. But what is “the right type”? We are used to eating juicy fruits from the fertilized female ficus carica. However, essential pollen is created only within the spring crop syconia of the hermaphrodite “caprifig” tree; it contains both short-style female and long-style male flowers, but is functionally male. Its name comes from the Latin “capra”, or goat, and in many Mediterranean countries, they were considered good for nothing but feeding animals. But the little fig wasp knows different. The fact that the caprifigs are unappetizing to animals, insects and birds gives her offspring the best possible chance of survival.

In spring and summer, caprifigs literally “smoke” with pollen. The little wasp must zero-in on such a treasure within 48 hours of hatching, or die unfulfilled. If she achieves her goal, she will re-enact the labours of her mother and countless grand-ancestresses by struggling through the ostiole, losing her wings, laying her eggs on the female flowers and leaving on them the male pollen she carried from her birthplace – thus providing the caprifig with the “payback” it requires the produce its next generation. Mission accomplished, she expires. One final, amazing thing occurs: a chemical signal is sent from Fig Central Control saying, “No more applicants need apply.” The open ostiole of the fertilized fig closes, and sometimes, a drop of sweet nectar is exuded and hardens, sealing the entrance firmly.

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Once fertilized, the fig may seal its ostiole with nectar. © Jude Irwin

Figs Foster Biodiversity Worldwide

The give-and-take or “mutualism” between wasp and fig is one of the most remarkable relationships in the natural world – and one of the longest successful partnerships. It has been studied avidly by many scientists, including Carlos Machado, Associate Professor of Biology at the University of Maryland. He states that, “Using fossil evidence for calibrating these data, we estimate the origin of the fig-wasp mutualism to have occurred 90 million years ago…(corresponding) well with several features of the break-up of the southern continents during the Late Cretaceous period.”

The main radiation of fig species took place no later than 20-40 million years ago. Today, there are between 750 and 900 species of deciduous Ficus worldwide – mostly in temperate and tropical zones, ranging from the towering hemi-epiphyte strangler figs of the rainforests whose dangling, twining roots engulf their hosts, to the small, potted Ficus benjamina plants that grace so many corporate waiting rooms. We are familiar with large-leafed, woody trees whose broad canopies give us welcome shade, but there are also many creeping vines and a vast array of indomitable shrubs, both wild and cultivated. Most figs shrug off drought or neglect and flourish in virtually any soil from heavy clay to sand; they march across the earth from the wild peaks of Afghanistan to California’s manicured valleys, and from the leafy hortas of Portugal to the parched plains of sub-Saharan Africa.

Because of the way specialized fig wasps interact with quite specific types of fig syconia, it is possible for many varieties of ficus species to grow side by side without cross-pollinating. So, instead of homogeneity of characteristics, we get lots of genetic differences among them. Scientists call this “species packing”. Preservation of genetic fig diversity results in different fruiting seasons. Ergo, there are figs available year-round in many habitats. And that, in turn gives all manner of creatures the greatest possible opportunity to devour their bounty. You might think having its fruit eaten is a bad thing for the tree, but of course, it’s not. Each fig seed is a tough little capsule that usually passes without harm through the digestive acids of man or beast, and the purgative compounds in the fruit are Nature’s way of encouraging these seeds to “go forth and multiply”.

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Great Hornbill, Buceras bicornis, eating figs. Lip Kee Yap, Public domain.

Edible figs, large and small, are so important to the survival of a biodiverse community of animals and insects that they are often called “keystone species”. Everything eats them: Capuchin monkeys and white-cheeked mangabeys, hairy fruit bats, langurs, pigeons and parrots, coppersmith barbets, Swallowtail butterfly caterpillars, snuffling bandicoots and bounding kangaroos, tortoises, catfish, and the Jesus Christ lizard – literally thousands of creatures are crazy about figs. And they depend upon them. So far, 990 bird species, 284 mammal species and at least 14 fish and reptiles have been documented as fig eaters. It is estimated that, if the fig trees in a single habitat such as a rainforest, were wiped out, 50-75 percent of all bird and animal biomass would be lost. (Terborough 1986)

So, next time you wander out into the garden to snaffle a few sweet figs before lunch, show a bit of respect for your generous tree, its secret flowers, and the first little wasp that gave her all so many millennia ago

More Fabulous Figgy Facts

* The Three Types of Edible Fig: 1) Caducous or Smyrna / Calimyrna type figs require pollination by the fig wasp; unpollinated figs drop. Other varieties in this group include Marabout, Inchàrio and Zidi. 2) Intermediate type figs set an early breba crop without wasps, but need pollination for their main crop. These include the Lampeira, King and San Pedro varieties; and 3) Persistent (or common) figs, whose all-female flowers do not require pollination, but develop figs via parthenocarpic means. Many garden cultivars are in this group, including Brown Turkey, Black Mission, Brunswick and Celeste.

* Good Health: Figs are one of the healthiest “fruits” you can eat. They are rich in fiber and minerals such as calcium, iron, manganese and magnesium as well as potassium, which helps lower blood pressure. Figs also provide pantothenic acid, otherwise known as vitamin B5, proven to play an important role in breaking down fats and carbohydrates. It also helps in making red blood cells, hormones you need for vigorous sex and stress-reduction and aiding healthy digestion. (Wow.) A derivative, pantethine, is being studied for its ability to lower ‘bad’ cholesterol. Go on. Eat another fig.

* Enlightenment: Buddha, also called Bodhisatva, is said to have achieved “Bodhi” or spiritual enlightenment while sitting beneath a large and sacred fig tree (Ficus religiosa) known as the “Bo” in Sinhalese.

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Temple beneath the sacred Bo tree”. Anonymous artist, 1810, British Museum. Creative Commons.

Fig Links:

For lots of fig-related photos and general information, visit http://www.figweb.org/ – a site created by Iziko Museums of South Africa.

For an astonishing list of what vertebrates eat which figs worldwide, click this link. https://figfrugivory.wordpress.com/

For a delicious fresh fig and pasta recipe (vegetarian, but includes cheese), see: www.chefbikeski.com/?p=2439. If you want to cheat, it’s lovely with thin slices of presunto tossed in at the last minute.

For more about potential biomass losses from destruction of “keystone species”, See: http://research.cnr.ncsu.edu/sites/millslab/wp-content/uploads/sites/13/2015/01/Mills93-Keystone.pdf.)

Except where public domain photos are credited otherwise, all photos and text © Jude & Keith Irwin Figueiró dos Vinhos, Portugal 2015. For permission to use any of this material email: proulxjude@gmail.com

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