A wasp works wonders for Smyrna figs
My barely heated greenhouse kept me in fresh figs well into fall, but decreased light and increased cold have made those juicy, ambrosial fruits a mere memory.
Now I go to the store and purchase dried figs, to me a totally different fruit: super-sweet, a bit crunchy and, of course, not at all juicy.
It’s winter, and plants no longer clamor for attention, so let’s focus on that crunchiness of dried figs. It comes from seeds, which I would never find in my own figs’ fruits. Botanically speaking, those “seeds” are the real fig fruits. What we commonly call a fig “fruit” is actually a hollow stalk whose inner wall is lined with the true fruits. (With that disclaimer off my chest, I’m going back to calling the hollow stem a “fruit” and the crunchy things inside the “seeds.”)
Those seeds result from pollination, which is no small feat for what might be thought of as an inside-out fruit.
For most kinds of fruits to develop, pollen from a male flower, or the male part of a bisexual flower, must first be dusted onto the female part of the flower. But Smyrna — the most commonly sold variety of dried fig — has no pollen.
A WASP IS PRESSED INTO SERVICE
Fig pollination is brought about by pressing into service a tiny wasp. Smyrna fig trees were introduced into California in the 1880s, but until fig pollination was understood, all the figlets on California’s first fig trees merely dropped to the ground before swelling.
Mediterranean farmers long ago discovered that Smyrna fig trees could be made fruitful by hanging among their branches fruits of inedible, so-called wild goat figs, or caprifigs. The caprifigs supply the needed pollen, which is carried into the developing Smyrna fruits by that tiny wasp.
The wasp is called Blastophagus, and her work is called caprification. Blastophagus’ eggs, as many as 600 in a single fruit, develop inside the caprifigs. At certain times of year, which correspond with caprifig fruit development, male wasps awaken, fertilize still-sleeping female pupae, and then die without ever leaving the caprifigs.
Female wasps emerge soon after, just when the male caprifig flowers are shedding pollen. As the wasps wend their way out of the caprifigs, they inadvertently pick up pollen.
THE WASP IS TRICKED
Once outside a caprifig, Ms. Blastophagus begins searching for an unpopulated caprifig in which to deposit her eggs, and here is where human trickery intervenes. Caprifigs, which are grown in separate orchards, are gathered just before the female wasps see daylight and are hung among the branches of Smyrna fig trees.
Ms. Blastophagus doesn’t know a caprifig from a Smyrna fig, so she works her way into the Smyrna fig’s eye. Unfortunately for her, the shape of Smyrna fig flowers makes egg-laying impossible. Fig pollination occurs as she frantically moves from flower to flower trying to lay eggs.
Eventually, the poor wasp dies from exhaustion. Most of the dead wasps are digested inside developing fruits, but you’ll occasionally find an intact one if you look closely. Of course, enough colonized caprifigs are left among the caprifig trees to perpetuate the wasp species.
DISBELIEF GIVES WAY TO DELICIOUS FIGS
Given the intricate and synchronized relationship between the two plants and an insect, it’s no wonder that a couple of decades elapsed before Californians were able to harvest their first ripe Smyrna fruits. At first, the idea of caprification was considered preposterous, the hanging of caprifigs in the trees mere peasant superstition.
Horticulturalist Dr. Gustave Eisen reported that he was “hooted down and some of the mob whistled” when he announced, at a horticultural meeting in 1887, his findings on caprification.
Fortunately for those of us who live where the climate is not conducive to caprification, many varieties of figs bear fruit without any pollination whatsoever. But for dried figs, Smyrna is one of the best. For better or worse, my figs, which are delicious fresh but not dried, are also seedless.