THE FIG INSECT ON WHICH DEPENDS A GREAT PLANT INDUSTRY
(Blastophaga grossorum, Grav.)
Into every dried Smyrna fig that you eat a queer little beast like this has crawled; unless she does so, no seeds will form, for the inside of a young fig is filled with flowers waiting to be dusted with pollen and it cannot develop until this is done. This tiny, female wasp, so small you can scarcely see her with the naked eye, is the pollen duster of this miniature flower garden.
The Blastophaga hatches out from a tiny egg which her mother lays in a special flower or gall in the flower cavity of a wild, inedible Caprifig that came originally from the islands off the Syrian coast. Her mate, an ugly little thing with no wings at all, hatches out before she does and mates with her even before she comes out of her tiny cocoon. After wandering about among the stamens in the cavity in the Caprifig until her back and sides are covered with pollen, she finds her way out through the hole in the end of the ripening wild fig and flies away in search of another young and ripening fig in whose gall flowers instinct impels her to lay her eggs.
The larger, juicier Smyrna fig attracts her, and she crawls inside, searching for gall flowers there. But the Smyrna fig has no special places for her eggs and, after wandering around over the flowers in the floral cavity she wanders out again, or dies. But in this scramble over the sticky stigmas of the Smyrna fig flowers, she irritates them and leaves upon them the pollen which she brought with her from the wild fig. This is what causes the young seeds of the Smyrna fig to grow and the fig itself to swell and become the honey-sweet fruit which we eat.
Without the visits of this tiny wasp the figs either fall off on the ground when young, or else form insipid tasteless fruits. So it might be said that the great fig industry of Smyrna hangs on the blundering instinct of this little creature.
Some enterprising Californians brought over and planted orchards of the Smyrna fig and could not understand why they did not bear. Then they brought in the wild Caprifig from Smyrna and planted it side by side with the Smyrna figs, but still with no result. Finally the experts of the Department of Agriculture were called in and solved the problem by introducing the insect, which had been left behind.
This little creature, in the picture, crawled out in my laboratory from a Caprifig which Doctor Rixford, the fig expert of California, sent me, requesting that I photograph his pets.