Part 10
It was one evening not long after our afternoon on Bungalow Hill, where Mary had found the mealy-bugs in the runways of an ant's nest under a stone, and I had told her about the clever little brown ants and their aphid cattle in the Illinois corn-fields. Ever since that afternoon Mary had been asking questions about ants, and so this evening I was translating bits to her from a new German book about ants. It told about the cruel forays of the hordes of the great fighting and robbing Ecitons of the Amazons; of the extraordinary mutually helpful relations between the Aztec ants and the Imbauba tree of South America, which result in the ants getting a comfortable home and special food from the tree, while the tree gets protection through the Aztecs from the leaf-stealing Ecodomas. It told of the ants that live in the hollow leaves of the Dischidia plants in the Philippine Islands, and the way the plants get even by sending slender aerial rootlets into the leaves to feed on the dead bodies of the ants that die in the nests. It told of the ants in this country that build sheds of wood-pulp over colonies of honey-dew insects or ant-cattle on the stems of plants; of the fungus-garden ants of South America and Mexico and Texas that bite off little pieces of green leaves and make beds of them in special chambers in their underground nests, so that certain moulds grow on these leaf-beds and provide a special kind of food for the ant-gardeners. It told of the ants that make slaves of other ants, and get to depend so much on these slaves that they can't even care for their own children, and it told about the honey-ants of the Garden of the Gods that make some of the workers in each nest--but that's what this story is going to tell about, so we had better wait.
But it was all a veritable fairy-story book, as any good book about the ways and life of ants must be. And Mary listened eagerly. She liked it. When going-home time came she had, however, one insistent question to ask. "What can I _see_?" she demanded. "What can I see right away; to-morrow?"
"Mary you can--see--to-morrow,"--and I think rapidly,--"you can see--to-morrow,"--still thinking,--"ah, yes--yes you _can_; you can see them to-morrow."
"But _what_ can I see to-morrow?"
"Why the animated honey-jars; didn't I say what? No? Well, to-morrow we can go to see them; in the Arboretum at the foot of the big Monterey pine. I think I remember the exact place."
"But I thought the honey-ants were only in Mexico and New Mexico and Colorado," says Mary. "Didn't the book say that?"
"Yes, that kind; but we have a kind of our own here in California. The sort that McCook found in the Garden of the Gods and studied all that summer twenty-five years ago is found only there and in the Southwest, but there are two or three other kinds of honey-ants known, and one of them that has never been told about in the books at all is right here on the campus. There are several of the nests here, or were a few years ago, and we'll go to-morrow and try to find one. It will be fine, won't it?"
"Fine," said Mary. "Good-night."
And so the next morning we went. The Arboretum is a place where once were planted almost all the kinds of trees that grow wild in California, besides many other kinds from Australia and Japan and New Zealand and Peru and Chili and several of the other Pacific Ocean countries. But the big, swift-growing eucalyptuses and Monterey pines have crowded out many of the other more tender and less-pushing kinds. However, it is still a wonderful place of trees. Many birds live there; swift troops of the beautiful plumed California quails; crimson-throated Anna humming-birds, crestless California jays, fidgeting finches and juncos, spunky sparrows and wrens, chattering chickadees and titmice, fierce little fly-catchers and kinglets. There are winding paths and little-used roads in it, and altogether it is a fine place to go when one has only a short hour for walking and seeing things.
And so Mary and I came with a garden-trowel and a glass fruit-jar to the foot of the big Monterey pine near the _toyon_. A _toyon_, if you are an Easterner and need telling, is the tree that bears the red berries for Christmas for us Pacific-Coasters. It is our holly, as the Ceanothus is our lilac, and the poison-oak is our autumn-red sumac.
At the foot of the Monterey pine we began our search for the honey-ants. We didn't, of course, expect to find them walking about with their swollen bodies full of amber honey, for the honey-bearers are supposed not to walk around, but to stay inside the nest, in a special chamber made for them. We looked rather for the honey-gatherers, the worker foragers.
Pretty soon Mary found a swift little black ant. But, no, it was an _Aphænogaster_ that--
"A feeno-gasser?" asks Mary. "What is that?"
"That has the curious, flat-bodied dwarf crickets living with it in its nests," I continue. "_Myrmecophila_, the ant-lover, they call this little cricket which has lost its wings and its voice and is altogether an insignificant and meek little guest unbidden but tolerated at the ant's table. And here, here is a big black-and-brown carpenter-ant going home with a seed in its mouth."
"Where is its home? Does it build a house out of wood? Let's follow it," Mary bursts in.
"No, we are after honey-ants, remember. We mustn't let ourselves get distracted by all these others. The carpenter-ants do make themselves a home of wood, but they do it by gnawing out galleries and chambers in a dead tree trunk or stump or in a neglected timber. That isn't exactly building, but it is at least a kind of carpentering, a sort of--"
"Is this one?" interrupts Mary, poking violently at an angry red-headed little slave-maker ant that seemed anxious to get off to its home where its slaves, which are other ants captured when still young and unacquainted with their rightful family, do all the work of food-getting and cleaning and taking care of the babies.
And then I recognized a _Prenolepis_, that is,--and I _do_ beg pardon,--one of our campus honey-ants. Of course I suppose they are elsewhere in California and perhaps north in Oregon and east in Nevada and Arizona, but I have only seen them here, and hence always think of them as belonging exclusively with us campus-dwellers. It was a little brown ant with black hind body and paler under side. It isn't particularly impressive, for it is only about one-eighth of an inch long, and its colors and appearance are much like those of many other ants, but there is something about it sufficiently distinctive to let one recognize it at sight.
The thing to do now, of course, was to find its nest. There are various ways of finding the nest of any particular ant you may happen to discover running about loose over the country, but not one of them am I going to tell you. They are good things to work out for yourself. Mary and I know how, and so we had little trouble and didn't have to spend much time in finding the home of our wandering _Prenolepis_,--there it is again,--campus honey-ant I mean. And that is a fair name for it, for McCook who found the famous honey-ants of the Garden of the Gods in Colorado named his kind _Myrmecocystus melliger hortusdeorum_, which is straight Latin and Greek for the "honey-pot ant of the Garden of the Gods." But _what_ a name for a little ant one-eighth of an inch long to carry!
It would take too many words and I am afraid would be too trivial a story for even this very happy-go-lucky little book to tell how Mary and I dug and dug in the ground near the foot of the tree, and how carefully we worked with our garden-trowel and mostly with our fingers! And how we traced out runway after runway and opened chamber after chamber of the honey-ant's nest until we found the honey-pantry with its strange jars of sweetness all hanging from the roof. The picture that Mary carefully sketched in, and that Sekko Shimada painted for us with his dainty Japanese brushes and little saucers of costly Japanese ink, shows very well part of the nest, that part that had one of the honey-rooms in. You won't see the base of the Monterey pine-tree in the picture, nor any of the other trees that were all around, because Mary didn't put them into her sketch, and we forgot to tell Sekko where the nest was. But the galleries and honey-chamber and the ants themselves are all right in Sekko's picture.
In some of the galleries we had found ants with considerably swollen hind bodies, which evidently had the stomach or crop well filled with some nearly transparent, pale yellowish-brown liquid. But it was not until we discovered the honey-pantry that we saw the extraordinary fully laden real live honey-jars, which were, of course, nothing but some of the worker ants hanging by their feet from the roof of the chamber, with their hind bodies enormously swollen by the great quantity of honey held in the crop. In opening the chamber we dislodged two or three of the honey-jars that fell to the floor and could hardly turn over or walk at all, so helpless were they. And one of them broke and the honey came out in a big drop, and I tasted it on the tip of my little finger, and it was sweet. So it was surely honey. And you should have seen how eagerly two or three other workers in the chamber, without swollen bodies, lapped up this sweet drop that came out of the body of the poor, broken honey-jar!
As we had broken into the home of the honey-ants and had pretty nearly wrecked it, it seemed only fair that we should try to help our honey-ants begin another home under as kindly conditions as possible. So we put as many of them as we could find, foraging workers, honey-holders, and the queen whom we found in a special queen room, into our glass fruit-jar with some soil, and brought them all home and put them into a formicary. Which is simply an artificial ants' nest, or house already arranged for ants to live in. It has a place to hold food and has dark rooms and sunny rooms, cool rooms and warm ones, all nicely fixed with runways connecting them, and food is put in as often as necessary and always in one place, which the ants learn to know very soon, indeed. This makes housekeeping easy and pleasant for the ants, and lets us see a great deal of how it is carried on, because there are glass sides and top to the house, so that by lifting little pieces of black cardboard or cloth we can look in and watch the ants at work.
The honey-ants' colony seemed to live very contentedly in our formicary, for they went ahead with all their usual business of laying eggs and rearing babies and feeding them, and finding honey and getting the honey-jars loaded with it and hung by their feet from the ceiling of their room, and all the other things that go on regularly in a honey-ant's house.
The principal thing we wanted to do, however, was to learn how the honey-jars got filled and also how they got emptied again! And this was not at all hard to find out, although we never found out certainly where the worker foragers got their honey in the Arboretum. McCook found that his foragers in the Garden of the Gods gathered a sweet honey-dew liquid that oozed out in little drops from certain live oak-galls near the nest. But our ants seemed to be getting their honey from somewhere up in the pine-tree, for there was a constant stream of them going up and down the trunk. Besides, many of those coming down had swollen bodies partially filled with honey, while none of those going up did. Now the only honey supply in the pine-tree that we know is the honey-dew given off liberally by a brown roundish scale insect that lives on the pine-needles. So we _think_ our honey-ants gathered their honey material from these honey-dew scale insects. But we have seen them collect honey stuff from various aphids and also from the growing twigs of live-oak trees. They seem to be willing to take it wherever they can find it.
Of course we had to provide a supply of honey for our indoor colony, and this supply was eagerly and constantly visited by the foraging workers. They would lap it up and then go into the nest and feed the live honey-pots! That is, a well-fed forager would go into the honey-pantry and force the honey out from its own crop through its mouth into the mouth of one of the live honey-jars. Undoubtedly the honey-bee honey we furnished them was considerably changed while in the body of the foraging worker.
But all the time the nurses and workers inside the nest needed honey for food. And this they got by going to the honey-pantry, and by some gentle means inducing the live honey-pots to give up some of their store. Mouth to mouth the feeder and the filled honey-ant would stand or cling for some minutes. And there was no doubt of what was going on. The honey-pot was this time forcing honey out of its own over-filled crop and into the mouth of the nurse.
Thus all the time there went on a constant emptying and replenishing of the strange honey-pots. What an extraordinary kind of life! Nothing to do but to drink and disgorge honey; to cling motionless to the ceiling of a little room, or lie helpless, or feebly dragging about on the floor and be pumped into and pumped out of! To have one's body swollen to several times its natural size by an overloaded stomach, and to be likely to burst from a fall or deep scratch!
But there is simply no telling beforehand what remarkable condition of things you may find in an ant's nest. There is an ardent naturalist student of ants in the great museum of natural history in New York, who keeps publishing short accounts of the new things he is all the time discovering about the habits and life of ants. And if I didn't know him to be not only a perfectly truthful man but a trained and rigorously careful observer and scientific scholar, I should simply put his stories aside as preposterous. But on the contrary, as I do know them to be true, I am more and more coming to be able to believe anything anybody says or guesses about ants! Which is, of course, not a good attitude for a professor!
Dr. Wheeler, this New York student of ants, is putting a great deal of what he knows about ants into a large book which, when published, will make a whole shelfful of green, red, blue, and yellow fairy books hide their faded colors in shame. For tellers of fairy tales cannot even think of things as extraordinary and strange as the things that ants actually do!
But what a prosaic lecture this story of the animated honey-jars has come to be. Mary is long ago asleep, curled up in a big leather arm-chair in my study, and I sit here in the falling dusk, straining my bespectacled eyes to write what will, I am afraid, only put other little girls to sleep. Which is not at all my idea in writing this book. It is, indeed, just the opposite. It is to make anybody who reads it open his eyes. But, "_Schluss_," as my old Leipzig professor used to say at the end of his long dreary lecture. So _Schluss_ it is!
HOUSES OF OAK
There are eight different kinds of oak-trees growing on or near the campus where Mary and I live. And each kind of oak-tree has several kinds of houses peculiar and special to it. Which makes altogether a great many styles and sizes of houses of oak for Mary and me to get acquainted with. For we have made up our minds to know them all, and something about the creatures that live in them. This is a large undertaking, we are finding, but an intensely interesting and delightful one. Some of it is quite scientific, too, which makes us proud and serious. We are keeping notes, as we did about Argiope and the way it handled flies and bees, and some day we shall print these notes in the proceedings of a learned society, and make a real sensation in the scientific world. Anyway we think we shall. Just now, however, we shall only tell the very simplest things about these houses of oak and their inhabitants, for we suppose you wouldn't be interested in the harder things; perhaps, indeed, not even understand them all.
Although, as I have already said, there are eight different kinds of oak-trees growing in our valley and mountains, two of these kinds, the live-oaks and the white oaks, are by far the most common and numerous. As one stands upon the mountain tops or foothills and looks down and over the broad valley, all still and drowsy under the warm afternoon sun, it seems as if you were looking at a single great orchard with the trees in it in close-set regular lines and plots in some places, and irregularly scattered and farther apart in other places. Where they are regular and close together, they really are orchard trees; where they are irregular and widely spaced and larger, they are the beautiful live-oaks and white oaks that grow in all the grain-fields and meadows and pastures of our valley. The live-oaks have small leaves, dark green and close together, and the head of the tree is dense and like a great ball; the white oaks have larger, less thickly set leaves of lighter green, and the branches are more irregular and straying and they often send down delicate pendent lines that swing and dance in the wind like long tassels. The live-oaks have leaves on all the year through; the white oaks lose theirs in November.
In both of these kinds of trees the oak houses can be found, but especially in the white oaks. And there are, as I have said, many kinds of the houses. Mary and I have found little round ones, big bean-shaped ones, little star-shaped ones, slender cornucopia-like ones, green, whitish, red-striped, pink-spotted, smooth, hairy, rough-coated, spiny ones, and still other kinds. Some of the houses are on the leaves, some on the leaf-stems, some on the little twigs, and some on the branches. Some of the houses stay in the trees all through the year, but most of them drop off in the autumn, especially in the white-oak trees, just as the leaves do.
We go out and hunt for the houses in the trees and among the fallen leaves on the ground under the trees. They are sometimes, especially the little ones, hard to find, for their colors and shapes often seem to fit in with their surroundings, so as to make them very hard to see. But others, like the big ball-shaped white ones shown in Sekko Shimada's picture, are, on the contrary, very conspicuous. If the houses are on the ground, or even if they are still on the tree and we think they are all through being made--and there are various ways of knowing about this, but the most important is the time of year--Mary and I bring them home with us and put them in little bags of fine cloth netting, tarlatan usually, the houses that are alike and from one place being put together in a single bag. Then we tie a string around the mouth of the bag and wait for the dwellers in the houses to come out.
For one has to be careful about trying to see the oak-house dwellers before they are ready to come out. It is much better to await their own sweet pleasure in this matter, than to go digging or prying in, for the houses have no doors or windows until just at the time the dwellers come out! In fact they make the doors as they come out. You will see, after we tell you a little more, that this arrangement is a very good one. Even as it is, various unwelcome intruders find their way into the house much to the annoyance and even to the fatal disaster of the inmates.
So we wait until the dwellers are ready to come out. Or if occasionally we really think we ought to see how things are going on inside, we chop a house or two open and see what we can see. What this is, usually, is a house's insides very unusual and curious, for the rooms occupy so little space and the walls so much. Sometimes there is only one room and that right in the middle, all the rest of the house being just a dense or sometimes loose and spongy wall all around it. In the single room, or in each of the several rooms, we find a curled-up little shining white grub without legs, and of course without wings, and with a head that doesn't seem much like a head, for it has no eyes nor feelers, and most of the time is drawn back into the body of the grub so that it is hardly visible at all. But there is a mouth on this silly sort of head, and the grub eats. What it eats is part of its own house!
The houses, or galls, as the entomologists call them, are of course not actually made by the insects that live in them; they are made by the oak-tree on which they are. But they are only made at the demand, so to speak, of the insects. That is, the oak-galls are formed only where a gall-insect has pricked a live leaf or stem or twig with her sharp, sting-like little egg-layer, and has left an egg in the plant-tissue. Nor does the gall begin to form even yet. It begins only after the young gall-insect is hatched from the egg, or at least begins to develop inside the egg. Then the gall grows rapidly. The tree sends an extra supply of sap to this spot, and the plant-cells multiply, and the house begins to form around the little white grub. Now this house or gall not only encloses and protects the insect, but it provides it with food in the form of plant-sap and a special mass or layer of soft nutritious plant-tissue lying right around the grub. So the gall-insect not only lives in the house, but eats it!
After it is full-grown, the grub stops eating. Then the house, or gall, stops growing and becomes harder and changes from greenish to some other color, and, in most cases, pretty soon drops off the tree to the ground. The gall-insect is still alive inside, of course, but is perfectly quiet and is simply waiting. It is at this time in the life of the houses and their dwellers that Mary and I collect them and bring them home and put them into little tarlatan bags. This is autumn, the time that the trees in the East turn yellow and red, but in California do not. They just stay green, but get quiet or turn brown or simply drop off their leaves and stand bare.
All through the autumn and winter the gall-insects do nothing inside their houses. Indeed we can take them out and keep them in little vials, and most of them get on very well. They require no food; they simply want to be let alone. But in early spring--and spring in California comes very early; indeed, it comes in winter!--they wake up and in a short time change into stout-bodied little real insect-looking insects with six legs, four wings, a round head with feelers and eyes and whatever else an insect's head ought to have. Especially sharp jaws. For each gall-dweller has now to get out of its house. And as there are no doors, it has to make them. Which it does with its sharp jaws, gnawing a tunnel from the center of the house right out through the thick hard wall to the outside.
When it gets out it flies around in lively manner for a few days, finally settling on a sprouting oak-leaf or bud or green stem or twig, and laying a few eggs, or several, or many, according to the habits of its special kind, and then it dies. And when the tiny white grubs hatch from these eggs, new houses begin to be made around them by the oak-trees, and a new generation of gall-insects is fairly started.