National Geographic : 1929 Jul
EXPLORING THE WONDERS OF THE INSECT WORLD Photograph by Paul Griswold IIowes A SMALL BEE SCRAPES POLLEN FROM ITS FURRY COAT The coming of such pests as the recently arrived Mediterranean fruit-fly (see pages Io, II), the European corn-borer, and the Japanese beetle sends shivers of well-founded dread through the American people; but if our bee friends were to leave us en masse we would be even more alarmed. Without their pollen-carrying activities most of our flowers and many of our fruits would disappear. resemblance to our present-day spring tails, fish-moths, and silver-fish, began to climb the ladder of winged evolution, re leasing themselves from the bondage of feet, they found opportunities for coloni zation, for multiplication, and for promot ing their freedom from enemy attack de nied to all creatures limited to legs for locomotion. AN EONS-LONG STRUGGLE Chetverikov, the Russian naturalist, de scribing the trends of early vertebrate and insect life, says that in geological times the vertebrates seemed bent on growing larger, defending themselves in the strug gle for survival by accumulating strength. The grass eaters grew larger and stronger, to save themselves from the flesh eaters, and the flesh eaters, in their turn, had to grow stronger and fleeter in order to hold their own in the contest. Finally, both got too big for their environment and both disappeared from the earth, leaving no living species to trace descent from them, and with only their fossil remains persist ing to proclaim their one-time existence. The insects chose another route to sur vival. With the brevity of life cycle that characterized them, a contest with the vertebrates in size would have been futile; but in smallness they could find a vast number of nooks where they could live in safety, thus filling the chinks and crannies of creation. Just as gravel, then sand and dust, more and more firmly fill the free spaces between the stones in a pile, so the hordes of insects, innumerable as gravel and small as sand, fill the crevices in crea tion left by the vertebrates. But even with their smallness the in sects of bygone geological ages needed protection. They achieved it by wearing their skeletons on the outside of their bodies and in their wings, and ever since have been growing smaller, although re taining their other major characteristics.