The fig wasp: a love story two millimetres long

The fig wasp, Blastophaga psenes, is about two millimetres long — smaller than the letter O on this page — and every fig that has ever needed pollinating owes its existence to her. She is born inside a fig, lives most of her life inside a fig, and dies inside a fig. Between those, she flies once.

One life, told in six steps

1. 1

   Born in a caprifig

   She hatches inside a gall — a flower in a caprifig that her mother turned into a nursery. Around her, her brothers are hatching too.

2. 2

   The males do their only two things

   Male fig wasps are wingless and nearly blind. They mate with the females while the females are still inside their galls, then chew an exit tunnel through the wall of the fig, and die. They never see daylight.

3. 3

   She leaves, dusted in pollen

   The female crawls out through the tunnel, past the male flowers clustered near the fig's eye, and comes out powdered with pollen. Now she flies — a few hundred metres, sometimes further on a breeze — looking for a young fig at exactly the right stage.

4. 4

   She squeezes through the eye

   The ostiole is so tight that she tears her wings and antennae off getting in. That's fine. She's never leaving.

5. 5

   Two doors, two endings

   If she's entered another caprifig, the flowers inside have short styles: she can reach the ovaries, lays her eggs, and the cycle starts again. If she's entered a Smyrna fig, the styles are too long. She tries anyway, and in trying she pollinates hundreds of flowers. Then she dies, having laid nothing.

6. 6

   The fig cleans up

   An enzyme in the fig, ficin, dissolves her completely within days. The fig ripens with real seeds — the nutty crunch that makes a dried Calimyrna taste the way it does.

The Calimyrna caper

In the 1880s, growers around Fresno planted thousands of Smyrna fig cuttings brought from Turkey, dreaming of a dried-fig industry to rival the Aegean's. The trees grew magnificently. Every June the fruit swelled to the size of marbles and fell off. Every tree. Every year. For over a decade nobody could say why, and plenty of people said the whole thing was a swindle.

A nurseryman named George Roeding worked out that the figs needed pollen from caprifigs and that only the wasp could deliver it — he's said to have proved the point by pollinating figs by hand with a toothpick, one at a time. What he needed was the insect. In 1899, working with the USDA's Walter Swingle, caprifigs carrying live wasps were shipped from Algeria to Fresno. The wasps survived, the caprifigs took, and in 1900 California harvested its first real crop of Smyrna figs. Roeding named them Calimyrna: California plus Smyrna. They're still grown in the Central Valley today, still pollinated by the great-great-great-grandchildren of that Algerian shipment.

Where the wasp lives now

The wasp can only live where caprifigs grow year-round, because it overwinters inside them. In practice that means the warmer parts of California and a few other Mediterranean-climate pockets — not Ohio, not Texas, not most of the country. That's why we keep a community map of sightings. If you're anywhere on it, Smyrna and San Pedro types are open to you. If you're not, stick to common figs and lose nothing: they're the ones we grow.