Figs & Wasps | How Plant and Pollinator Work Together
If you’re like me, you’ve probably given little thought to figs – aside from how delicious they are. But a quick look into the lives of figs reveals an entirely different picture: a remarkable and complex partnership between plant and pollinator. So what exactly are figs, what is a fig wasp, and why are they so special?
Figs Are Flowers, Not Fruits
Our local supermarkets are a categorical minefield. Granted that most of us are now well aware that tomatoes and avocados are technically fruits and not vegetables, while an aubergine, interestingly, is actually a kind of berry – and the same goes for bananas. But while this botanical treachery has been exposed in some cases, others have managed to slip under the radar: Right under our noses, the fig has been masquerading as a fruit.
That's right – what most of us would have smugly placed in the ‘fruit’ divide is actually not a fruit at all, but an inflorescence, a core of hundreds of tiny, delicate flowers, clustered within a bulbous stem. Cut open a fig, and the psychedelic maze you see within are individual flowers, and the crunchy bits, the seeds of each flower.1
Because figs are technically the flowers of a fig plant and not fruit, in order for the plant to reproduce, these flowers need to be pollinated. But, as you can imagine, pollinating the fig’s internal flowers is nothing short of mission impossible. Only one small but significant visitor has successfully undertaken such a task: the fig wasp.
At the size of a mosquito, this tiny invertebrate gives its life in service to pollinating the fig, and in return, each fig provides a safe and accommodating nursery to hatch and raise young.
Did you know that drones can be used to pollinate some agricultural crops? Read about pollination here.
Fig Plants Need Fig Wasps
Fig plants have remarkable relationships with fig wasps. It is a relationship so complex, it can be difficult for us to understand who initiated it, and who is getting the better of the bargain. Of the 850+ types of fig plant, almost all have their own species of fig wasp which has uniquely adapted to its partner fig (although certain wasp species have evolved to be generalists, allowing them to pollinate a number of fig plants).3
Did you know that figs are a key species used in reforestation? Learn more about how figs impact biodiveristy here.
These incredibly synchronised relationships didn’t just happen overnight. The fig–wasp association is prehistoric, the origins of which have been dated as far back as 90 million years ago (35 million years prior to the mass extinction of the dinosaurs).4
It’s thought that sometime before the plant and wasp’s fortuitous encounter, the flowers on fig plants turned quietly inward, coming to form the floral caverns we know today. This seismic shift changed the course of history for both organisms: For the fig plant, this evolutionary adaptation meant committing the highest form of monogamy. No longer would any other creature – from bees to birds, bats or even the wind, assist the plant in pollination. By sealing themselves off to the outside world, these blossoms triggered what was to become one of nature’s most enduring and mutualistic partnerships.5
Fig’s Pollination Cycle
Created by Andrea Van Den Berg
When a fig is ready to be pollinated, it emits a scent alluring only to the fig’s partner wasps. A female wasp, reaching one of these figs, tunnels her way through a needle-sized opening at the fig’s base. Tragically, each time a wasp does this she unknowingly commits the ultimate sacrifice. As she wriggles her way down the narrow hole, her wings and antenna get ripped away, rendering her flightless. She will live out the rest of her two-day lifespan inside the fig, never to take flight again.
Inside the fig’s chamber, the mother wasp gets to work laying eggs in as many minuscule flowers as possible before she perishes. The fig plant chemically detects each egg as it is deposited into the flowers, and responds by surrounding the eggs in plant tissue. This provides the larvae with food for when they emerge.6
Over the next few weeks, the eggs develop and the male hatchlings emerge first. Not resembling wasps at all, wingless with worm-like bodies, the males have one life mission: To fertilise the female larvae before they hatch. After fertilising the females, the males use their jaws to bite through the fig’s flesh, creating exit routes for their female siblings. Completing their life's work, the males crawl back inside the fig’s cavern to die.
Soon after, female wasps are born as pregnant queens, carrying with them the next generation of wasps. As the females make their way through the exit channels left by the males, the fig’s pollen becomes fixed to their bodies. Surfacing for their first time, the pollen-laden females take to the sky in search of the right fig plant to deposit their eggs.7 Disproportionate to their minute size, fig wasps travel farther than any other known pollinator, covering distances as far as 10 kilometres in less than their 48-hour lifespan.8 At the end of this epic saga, a female wasp makes her way down into a new fig’s dark inner cavity, bringing with her the pollen from her birth-fig, pollinating her new abode. The process starts anew.
Figs and Wasps Evolving Together
Symbiotic relationships can be found throughout nature. The relationship between most flowering plants and pollinators is symbiotic – flowering plants provide food for pollinators in the form of nectar or pollen, and in return, pollinators facilitate the dispersal of pollen for the plant to reproduce. Fortunately, in most cases, the diversity of flowering plants and pollinators means this exchange is relatively elastic: if one species of pollinator were not present, flowering plants would still be pollinated by other visiting species, and vice versa.
This is where the fig wasp and fig pollination relationship differs. Figs and their wasps are more than symbiotic benefactors, they are partners. As Nigel Tucker, one of Australia’s leading tropical ecologists tells me, “Figs and fig wasps have a totally obligate relationship.” Through their exclusive devotion to one another over millions of years, the two species have evolved in near-perfect symmetry, shaping both their physical and behavioural traits – a process biologists call ‘codependent evolution’. The result is a connection so profound, neither organism can exist without the other. Take one away, and the other falls.
So Are Figs Vegan or Do We Eat Wasps?
Now you’re probably wondering, do I eat a wasp each time I eat a fig? And the answer is – maybe. Of the various 850+ fig plants, most wild species require pollination by a wasp. So, if you happen to eat one of these varieties, chances are you’re getting a little added protein with that fig (which is why some vegans choose to avoid figs altogether). However, commercial varieties you find at your local supermarket are usually cultivated without pollination, grown from cuttings and producing fruit without seeds.9 Some figs have even been bred to be parthenocarpic, which means they reproduce asexually, without any pollen transfer at all. An example of this is the common Californian fig, Ficus carica, which makes up 90% of America’s fig consumption.5
In short – it’s unlikely you’ll find any little pollinators in your supermarket figs, but even if you were to eat a wild fig, the carnivorous enzyme released by figs as they ripen, known as ‘ficain’, effectively digests the internalised wasps for nourishment, leaving no trace of them by the time you take a bite.10
Will you be inspecting your figs for fig wasps? Let us know in the comment section below!