Thursday, 25 August 2016
True or false? Figs contain dead wasps
On a moonlit night in southern Africa a reproductive race is about to begin. The stakes are high but so are the risks. Most of the competitors will be dead or doomed by dawn. The starting line is a solitary fig tree whose gnarled form towers over a small stream. Figs hang in clumps from its branches like a plague of green boils. Tonight they erupt with life.
An insect emerges from a hole in one of the figs. She’s so small you could swallow her and not notice. She’s a fig-wasp with an urgent mission and her time is running out. All around her, thousands of her kind are crawling out of figs. Each one is a female with the same quest and each faces immediate danger.
So begins my new book’s chapter on fig-wasps, the tiny stingless insects that fig trees depend upon to pollinate their flowers and which can only breed inside figs. This 80-million-year-old partnership is a textbook example of species evolving together. Each of the 750-plus species of figs relies on its own species of fig-wasps, and vice versa.
My book shows how the world would be a very different place without fig-wasps. Hundreds of species of wild animal would go hungry, with knock-on effects for the thousands of other plant species whose seeds these animals disperse. Without fig-wasps there would have been no Ficus religiosa tree for the Buddha to sit beneath as he attained enlightenment. There would have been no fig leaves to protect the modesty of Adam and Eve, no banyan (Ficus benghalensis) to astound Alexander the Great.
Thanks to fig-wasps, fig trees and their figs have shaped the world about us and have influenced diverse human cultures in many remarkable ways. The best could be yet to come, as these species can be vital allies in our efforts to restore degraded rainforests. But when Ben Crair wrote about figs in the New Yorker this month, what caught the attention of many readers was his line: “When you eat a dried fig, you’re probably chewing fig-wasp mummies, too.”
While that is certainly true of the hundreds of wild fig species, we tend to eat figs of just one species: Ficus carica. This plant is among the first that people ever cultivated for food – several thousand years ago. Over that long history farmers bred some Ficus carica varieties that no longer need wasps to produce ripe figs. So, for those varieties, there’s no trace of a wasp. Great news for vegans!
Other Ficus carica varieties do need wasps to pollinate their flowers in order for them to develop seeds, then become sweet and ripe. But as Anna Rothschild explains so well in her new Gross Science video (above), the wasps are so small and so few that you really won’t notice them.
Rest assured, when you bite into a fig, any crunch comes from fig seeds not wasp corpses.
*My book will be published in the UK (and ebook) on 8 September 2016 as Ladders to Heaven: How fig trees shaped our history, fed our imaginations and can enrich our future. A North American edition, entitled Gods, Wasps and Stranglers: The Secret History and Redemptive Future of Fig Trees is out in November 2016.