Is the pollen ripe just when the flowers are ready to be fertilized? How in the world does it get in through the narrow door of the fruit? How does it get scattered inside, so that hun dreds of stigmas receive it? These questions put the scientist on the right track. He set a watch upon the Capri fig trees and the Smyrna trees in their own country.
Meanwhile, Mr. Roeding, up in his orchard in Fresno County, California, was able to get the answer: "Yes!" to the first question. He took pollen from the Capri figs and forced it into the Smyrnas' doorways, tagged the fruits thus treated, and waited for results. The tree dropped all the fruit but the ones that received the pollen he administered by hand. They swelled to full size, ripened, and had the fragrance, the flavor, and the sweetness of the Smyrna figs at home! This was in 189o. The missing link was now sought with all diligence, and found in the orchards of Turkey. A tiny wasp, so small as to be almost invisible to the naked eye, was seen to enter the "eye" of the Capri fig, and the same insect was found in the other figs at blossoming time. The magnifier discovered this hungry wasp searching each individual flower for its sac of nectar. Once identified, it was easy to recognize the fact that these midge-like insects were not at all scarce. The industry of fig-culture depended upon them! Without them, the whole world would go fig hungry.
How startled the nectar-loving little Blasto phaga would have been to learn what a grave responsibility rested upon her — ineso-thorax! (Insects do not have shoulders.) Is an insect ever conscious of the fact that it carries pollen from flower to flower? Never! She cannot avoid smearing her legs and body with sticky nectar, and dragging over the powdery stamens and the waxy stigmas, all ready for the vitalizing dust that en ables them to set seed. But the insect is all uncon scious of doing a work for the flowers, or the tree. She is selfishly gathering stolen sweets. Her own well-being and that of her growing family are her sole aim.
Turkey in Asia and California are many days' journey apart. Often captured Blastophagas
were shipped to America, but they died on the way. I suppose it is hard to give sufficient air in a package that contains insects small enough to go easily through the meshes of ordinary cheesecloth! It is hard to supply them with proper lunch for two or three weeks. But the difficult undertaking at last succeeded. And the immigrant wasps took up their abode in the Capri figs, and made them selves at home in the sunny climate of California. The year 1899 saw our first crop of Smyrna figs ripen on the trees, as the result of the bringing in of the Asiatic wasp that fertilizes the flowers.
The grower "caprifies " his trees by hanging fruits of the wild Capri fig in the branches of the orchard trees, and thus making the distance short that the insects have to go for their nectar supply. Of course it is imperative that the wild species be planted near by. Only a few are needed to supply many of the fruiting kinds with pollen.
Now the nurserymen who supply young trees for an orchard of figs send the necessary number of wild ones, and when the time of fruiting arrives, (and that is within three or four years of the setting of the trees) he sends a supply of the wasps to get them established in the orchards. Usually after the first supplies are received, the grower pays no more attention to the means by which his fruit is set. Nature has established an automatic system of reciprocity between the insect and the tree, and the owner has only to gather his figs and market them.
The giant fig trees of California are the wonder of the visitor, used to the comparatively small orange and other orchard trees he has seen. One veteran, planted in 1856 on the Rancho Chico, spreads Iso feet, and its branches, by striking root, form pillars, like the banyan-tree of India. This reminds us that the fig and the banyan-tree and the India-rubber tree are first cousins — members of the same genus, Ficus. The sticky, milky juice of the fig, that gets on your fingers when you pull a ripe one from the tree, is not unlike the milky latex which hardens into rubber.