Insect Stories

by Vernon L. Kellogg

I like the salt marshes of California. They are a change and relief, in their soothing monotony and simple plant life, from the lush and variegated flower fields, the dense and hostile chaparral thickets, the dark forests of great trees, and the miles of artificial plantations of orchards and vines. On the marshes you are greater and more important than the plants. In an orchard or a giant-tree forest, you feel second-rate someway. The fruit-trees have men for servants, while to the giant trees with their outlook from a height of three hundred feet and their memories of two thousand years, a man is no more than an ant. But in the marshes you feel that you are much more important a kind of creature than the pickle-weed, and that is almost the only plant that grows there.

There are many curious little bare dry spots in the marshes where we know it. Flat, smooth, salt-encrusted, clean white spots rather circular in outline, and perhaps twenty feet in diameter. All around is the low thick growth of fat-leaved pickle-weed, but for some reason it doesn't invade these pretty little empty rooms. Mary and I like to lie on the clean dry floor of one of these unroofed rooms and look up at the blue sky and out beyond the low side walls of pickle-weed far across the flat marsh stretches, over the shining bay, and on through the quivering blue to the beautiful mountains that bound our views on both sides. On clear afternoons we can see a gleaming white speck on the top of the highest mountain in the eastern range. That is the famous Lick Observatory, where the astronomers are looking always into the sky to read the riddle of the stars and planets and comets. We feel rather small, Mary and I, when we realize that we are only loafing or at best watching insignificant little insects and collecting wasp holes that lie at our noses' ends, while those men up there are looking at wonders millions of miles away. But we are so interested and contented with our small doings and small wonders that we do not at all envy the astronomers on the mountain top. While they watch the conflagrations of the stars and the mighty sailing of the planets through the blackness of space, we watch the work and play and living of our lowly companions on the sun-flooded marshes. They like the cold glittering sky; we like the warm brown earth.

We had been lying quietly on the white salt sand in one of the unroofed marsh rooms for some time this September day before we saw the first wasp begin to work. She was standing on her head, apparently, and biting most energetically with her jaws, cutting a little circle in the salt crust. When she got the circle all cut, she tugged and buzzed until she dug up, unbroken, the little circular piece (perhaps one-third of an inch across) of crust. She dragged this about three inches away. Then she returned to the spot thus cleaned and dug out with her sharp jaws a bit or pellet of soil. Holding this in her mouth, she flew away about a foot and dropped it. Then came back. Then dug out another pellet of soil and carried and dropped it a foot or so away. Then back again and so on until it was plain that she was digging out a little cylindrical vertical hole or burrow. As the hole got deeper, the wasp had to crawl down into it, first with head and fore legs, then with head and half her body; finally her whole body, long legs, wings and all, was hidden as she dug deeper and deeper. She had to come out of the hole of course to carry away each bit of dug up soil. She always backed upward out of the burrow, and all the while she was digging she kept up a low humming sound. It was this humming sound that attracted our attention to other narrow-waisted wasps like the first one. By moving about cautiously and listening and looking carefully, we found more than a dozen others digging holes, each one going about the work just like every other one.

When our first wasp had made its hole deep enough—this took a pretty long time; we found out later that it was about three inches deep—she brought back the first little circular piece of salt crust and carefully put it over the top of the burrow, thus covering it up entirely and making it look as if no hole were there. Then she flew away, out of the little bare room and off into the pickle-weed somewhere. We waited several minutes but she didn't come back, so we turned our eyes to another wasp near by which had its hole only just begun. It was interesting to see how closely like the first wasp this second one worked. Prying and pulling with the jaws, the same fluttering of the wings and humming, the same backing out of the hole and the swift little flight for a foot or two feet away from the hole to drop the pellet of soil.

I tried to point out to Mary that this was the way animals do which work by instinct and not by reason. That all the animals of the same kind do things in the same way, and that they do them without any teaching or imitating or reasoning out. They are born with the knowledge and skill and the impulse to do the things in the particular way they do. But Mary found this very tiresome and let her eyes rove, and it is well she did or we might not have made our great discovery: a really thrilling discovery it was for us, too.

The first wasp had come back! But not empty handed, or rather not empty mouthed, for in her pointed jaws she held a limp measuring-worm about an inch and a quarter long. A measuring-worm or looper is the caterpillar of a certain kind of moth, and it loops or measures when it walks because it has no feet on the middle of the under side of the body as other caterpillars have, and so has to draw its tail pretty nearly up its head to take a step forward. This naturally makes its body rise up in a fold or loop. "See," cried Mary, "the wasp is going to put the measuring-worm into the hole."

That is exactly what happened. How the wasp could tell where the hole was, was surprising, for it had so carefully put the bit of salt crust in place that you couldn't tell the top of the hole from the rest of the crust-covered ground. But our wasp came straight to the right place. Perhaps as a carrier-pigeon comes to its loft from a hundred miles away, or a cat carried away in a bag to a strange place finds its way quickly back home.

Some of the other wasps that we watched later weren't so sure of their holes, though, and other people who have watched digger-wasps in other places have found them showing varying degrees of uncertainty about locating their nests. Mr. and Mrs. Peckham, who have studied the behavior of the various kinds of digger-wasps more than anybody else in this country, have concluded that the wasps "are guided in their movements by their memory of localities. They go from place to place quite readily because they are familiar with the details of the landscape in the district they inhabit. Fair eyesight and a moderately good memory on their part are all that need be assumed in this simple explanation of the problem."

But quite different from this conclusion is that of Fabre, the wonderful French observer of wasps, who experimented on them in regard to this matter of finding and knowing their holes, by carrying them away shut up in a dark box to the center of a village three kilometers from the nesting ground, and releasing them after being kept all night in the dark boxes. These wasps when released in the busy town, certainly a place never visited by them before, immediately mounted vertically to above the roofs and then instantly and energetically flew south, which was the direction of their holes. Nine separate wasps released one at a time did this without a moment's hesitation, and the next day Fabre found them all at work again at their hole-digging. He knew them by two spots of white paint he had put on each one.

"Are the wasps guided by memory when placed by man beyond their bearings and carried to great distances into regions with which they are unacquainted and in unknown directions?" asks Fabre. "By memory so quick that when, having reached a certain height at which they can in some sort take their bearings, they launch themselves with all their power of wing towards that part of the horizon where their nests are? Is it memory which traces their aerial way across regions seen for the first time? Evidently not," emphatically declares Fabre. So there you are. Where doctors (of science) fall out it is not for you or me to decide.