The Wonder of the Fig (Part 2)
The Wonder of the Fig
(Part 2- The Pollination)
And now it is time to introduce the other protagonist in the story- the wasp. It’s a tiny insect; indeed the fig wasps are much smaller than other well-known wasps. These fig wasps are the sole pollinators of the figs, and they both are utterly dependent on each other. Almost all of the 850 species of figs have their own special species of wasps for pollination. Take away the wasps, and the figs will have absolutely no way to reproduce, take away the figs and now the wasps have no way to exist.
Let us take a look at a typical life-cycle of the wasp. All wasps are born inside the fig fruit, under the tiny female flowers located deep inside it. The tiny male flowers are typically located at the end of the fruit, towards its exit (also works as entrance). The wasps will grow under female flowers that are already pollinated by some earlier wasp, and the infant wasps will feed on the seed before turning into adults and breaking out of the egg-like capsule. Inside the fig fruit or our ‘enclosed garden’, the male will hatch first and search inside for female wasps. When he finds a female wasp, he will chew his way through the ovule wall (ovule is a part of the fig’s female flowers and all wasps are born there) and he will mate with the still unborn virgin wasp.
She then emerges from the capsule and now her own journey begins (adjacent picture). What happens next varies from species to species but here is a typical story. The female now looks for male fig flowers inside the fruit that produce pollen, and brushes all that pollen systematically on her body and stores them safely in her breasts. Notice how careful and deliberate is her action storing the pollen. Instead of being a passive agent like the bee, she actively brushes them on her body and stores them in her custom-built pollen-carrying sockets on her breasts.
Now laden with this precious fig pollen, the female leaves the fruit and goes into the sunlight for the first, but also the last time. The males never leave the fruit and hardly ever get to see the light of the day and their life cycle is over inside the darkness of the fig itself. Usually the males will help the female wasp to escape the fruit by boring a hole in the entrance/exit.
Once outside in the open air, it is now the female’s task to search for the right kind of fig which is in the right phase of its life and ready to receive pollen. Once she finds such a fig, she will struggle and wiggle her way through the entrance of the fig, and most often she will lose her wings in the painful process. But she doesn’t mind losing the wings as she won’t need them further. Once inside the fruit, she now carefully deposits the pollen in all of the female flowers inside the fruit and completes the act of pollination. Later she will deposit her own eggs in some of them but not all, and die inside the fruit once the task is done. Also, keep in mind that the pollinated female flowers in which she has deposited her eggs will not grow into seeds as her own eggs will devour the seed (true for most monoecious species, we will look at dioecious figs in later parts where the mechanism is much different). Only those female flowers that she pollinated but did not burden with her own eggs will continue to make a seed for the fig.
In the next part, we'll see how and why the female wasp does not lay her eggs in all of the pollinated flowers when she seems to have an immediate advantage in doing so.
Sources:
1) ‘Climbing Mount Improbable’, Richard Dawkins, 1996
2) http://nirmukta.com/2012/
3) www.figweb.org
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