Guest Author - Alegra Bartzat

The genus Ficus, commonly known as the fig tree, has an interesting and unique natural history. To begin with, what we call the fig “fruit” is not a fruit at all. The fig is called a syconium, a very special kind of inflorescence. That is a bundle of big words; so let me backtrack. An inflorescence is a group of flowers growing together from one branch. A syconium is an inverted inflorescence. That is, a cluster of flowers growing together INSIDE a branch. If you never noticed, every single fruit tree blossoms with flowers before growing the fruits. You will never see a fig tree blossom because the flowers are inside the fig.

No let’s think about what flowers do. Flowers are there for plants to exchange genetic material before reproducing. Male flowers and female flowers exist, but they can’t move around, so how does the pollen get from one flower to the next? Pollinators. And the case of fig trees, that means wasps. You need wasps to have figs. If all the wasps died, all the fig trees would die.

I know you’re now wondering, if the flowers are inside out, then how do the wasps pollinate them? There is a tiny hole at the bottom of each fig, sometimes a little bit of sappy nectar oozes out the bottom. The female wasp crawls inside that hole and pollinates the fig as she lays her eggs in some of the flowers. Usually more than one wasp can lay eggs inside a fig, and as all the wasps hatch and emerge, they mate. The females crawl out the hole to find a new fig. The males don’t even have any wings!

And get ready for the gross part. The females that lay their eggs inside the fig, thereby pollinating the flowers… She dies in there. That’s right, inside each fig is at least one dead wasp. But don’t worry, the wasp crawls inside of there so early on in the process that, actually, nothing remains inside the fig from the wasps. They decompose and are essentially re-absorbed by the plant. I just wanted to gross you out there for a minute.

There are hundreds of species of figs, so the story above is a generalization. Some figs have both female and male plants, others have hermaphrodite plants. Almost every fig plant has evolved with its very own species of wasp to pollinate it. So we don’t just need some wasps, we need all the different wasps.

If you can believe it, there is even more to the fig family that this amazing pollination story. Ficus citrifolia, the only species mentioned specifically, has yet another dimension to its story. The seeds that develop inside the fig, the crunchy bits in a dried fig, are what grows into a new plant. I know; I know! That’s not the good part. Most of these seeds either fall to the ground or are eaten by animals or birds and deposited far away from the mother plant, in a nice piece of dirt. But Ficus citrifolia gets deposited in the branches of other trees; it only grows in the canopy of the tropical rainforests. Here, high above the earth, it begins its life. As it grows, it drops its roots down, down, down to the earth many stories below. As the roots attach themselves to the earth, the fig tree grows larger, the roots get bigger, and it slowly over grows, choking and strangling its passive host to death. For this reason it is called a strangler fig.

Other figs have stories unique to their species, and all the figs have an intimate relationship with wasps. So the next time you bite into the luscious bundle of flower, enjoying its high calcium content, think about the amazing natural history of this inverted inflorescence!