ANT STUDY IN THE BIOLOGY CLASSROOM

ANT STUDY IN THE BIOLOGY CLASSROOMBY A. S. WINDSOR

General Biological Supply House, Inc.,Chicago, III.

Modern biology is a dynamic science. Life processes must beobserved and correlated with the knowledge of structuresgained from dissections, otherwise the teacher does not con-sider his task as complete. You, the biology teacher of today,spend much less time over dissecting trays and therefore candevote a greater share of attention to field work and the studyof living plants and animals in your laboratories than was thecase with your predecessors. In this way alone, can your stu-dents find out about their own status in this environment ofliving beings; can they properly orient themselves in a pulsat-ing world of creatures, all to some small extent, at least, depend-ent upon each other. A decade or two ago and we read a smatter-ing of biology out of a textbook, while the real world laboratorylay unexplored! But not so today! Many biology teachers areso successful in this newer, this living biology, that they havemade it possible for their students to observe in the classroomsome living examples of practically every phylum in the animalkingdom.

Insects, which far outnumber all other terrestrial animals,are naturally most easily available for study. It is not surprisingto find a whole host of representatives of this class which arestudied quite commonly in your laboratories. Almost anyonecan obtain living moths, mosquitoes, blow-flies, praying man-tids, walking sticks, cockroaches, grasshoppers, beetles and thelike, at some season during the year, so that a thorough studyof their life histories and habits is possible. I should like torecommend that we make more commonplace the intriguingstudy of ant life. Ants represent the highest type of social in-sect life and are to be found abundantly in almost any givenlocality�what is more important, at almost any time of theyear. Please do not be surprised when I tell you that you cankeep colonies going throughout the entire year if you wish. Or,you may wish to ^put one over^ Sir John Lubbock who keptone colony under observation for more than seven years! Itseems rather peculiar in one way, and yet nonetheless true, Ibelieve, that a high percentage of people seem to have an in-nate fascination for these denizens of the dirt and their activi-

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ANT STUDY IN BIOLOGY 61

ties. Did you ever stand over a group of the small brown lawnants, busy excavating their underground runways, and not feela certain admiration for them, even though you knew thattheir industry was to the immediate detriment of your lawn?Unconsciously, you were beginning your ant study.

I seem to sense that there are two fundamental questionsyou are about to ask me�call it mental telepathy or the nat-ural result of having talked to teachers individually about thematter. First, "How may I introduce this study to my stu-dents?77 and secondly, "What observations are we likely tomake which would so captivate student interest as to insure thecomplete success of the study?77There are two ways for initiating the study of ants and I

shall have to let you decide whether one means is to take prece-dence over the other. In my several years of experience in myhobby, I shall have to say that I do not regard either as com-plete within itself, that each must be supplemented by theother. Field study is the logical beginning point. On one of yourfield trips while the weather is still warm, locate a fairly largeant mound�but do not disturb it or the orderly processes ofthe inhabitants. Sit down beside it. Take notes�have groupsof four or five members of the class rotate at the pleasant taskof recording every observation made. Prompt them with suchquestions as: "Are all the workers of the same size?77 "Do youfind these ants on any of the weeds or low shrubs in the im-mediate vicinity?77 and "Why are they there?77 You see how justa little thought will provoke an endless barrage of questions,but mind you, it is your duty to offer these prompting questionsand that of the student to try to make sufficient observationsto enable him to answer each satisfactorily. And thus you willfind that a new world of interest is opened up for the entfreclass.These observations, stimulating though they can be, leave

something to be desired. The students can appreciate all theyhave seen, but try to keep them from searching deeper to findwhat goes on within the portals of this earthen empire! Theywant to know what mysteries are hidden from their view.Being mindful of your conservation ideals, allow one student todig into the mound with trowel. Doubtless you will find manyof the developmental stages, as well as the winged male andfemale castes which could not be seen unless this action weretaken. Place this general mixture of ants, their brood and earth

62 SCHOOL SCIENCE AND MATHEMATICS

into a jar for removal to the laboratory�and carefully returnthe earth of the mound to as nearly the former condition aspossible. Never leave an unsightly wound in the mound.

This brings us then to the second means for initiating thestudy, that of laboratory observations. One may wish to pro-ceed in the simplest possible manner at first, and, if so, leavethe ants in the jar of earth; but substitute a cloth for the lid.It will not take long for them to set up suitable living quartersin this modest home. Construction of runways, care of brood,reactions to light and many other interesting nest habits canbe observed without the expenditure of one cent. When youhave done about as much as possible with this arrangement,then I would suggest that you remove the ants and brood onlyto a flat type, earthless nest, which is by far the best for con-trolled study. For a quick transfer when the temperature fallsbelow 32°F., one may work outside of the building so that theants will become sluggish and, when massed together at thebottom of the jar, may be transferred to the cold nest by for-ceps. Or better, on a laboratory table, set up a barricade�make a corral to use a cowboy term�of plaster of Paris, heavygrease, or arrange a water moat. Place the flat nest inside thisand, near to it, empty out the contents of the jar. Eventually,the ants will leave the dirt as it becomes drier and take up theirresidence in the more humid nest, where there is food. Whilethis latter procedure takes longer, it is the more satisfactorymethod.There are many different types of observation nests avail-

able. Each has its good points. If you find it more advantageous,construct your own ant home. Wood is a desirable material formost species. Cement, while frequently used, seems less desir-able than wood. Plaster of Paris- is quite satisfactory as a"storage case^ and in combination with a wooden chamber is anexcellent means for keeping the laboratory colony. The displaycases on the table before you illustrate some possible types.At any rate, we have now started upon our serious study of

ants and we should now refer back to our second question youasked me about the interesting observations which await usin this study. For the sake of convenience, will you consideryourselves as having come upon an imaginary visit to my"ant round table^? By so doing we shall have our choice ofabout twenty different colonies and I am sure that this willallow us within a relatively short time to make a wide range of


observations which might easily require several weeks were weto have but one single group under observation. Mind you,these are all common Northern species and doubtless most ofthem occur in your own locality.Perhaps the most striking ants in this miniature zoo are the

large black Carpenter ants (Componotus pennsylvanicus), alltoo well known to most farm boys who have had any wood-chopping experiences. The true story as to the origin if thisparticular colony is interesting as I reflect back upon it. My8-year old son discovered it. I had looked for several weekswhen out in my usual collecting haunts far from the city, try-ing to locate a colony to add to my group but all of my effortswere in vain. While playing, the boys decided that they wantedto build a small fire in a vacant lot and as fuel, took an oldcedar post which had been stored under the front porch of ourhome. They were surprised, upon splitting it, to find a centralcavity packed with a black mass (this was during cold weather),which turned out to be these same ants which we are observ-ing mentally. They saved them and I was agreeably surprisedto learn of the ^catch^ when I returned home in the evening.This is truly typical of ant-hunting; you never know just whatyou may find, but usually�I might say, almost invariably�there is some thrill in store for you for each day which youspend in the field. It is seldom that I return without somethingwhich I wanted even though it might have been a far cryfrom the creature which I had hoped to find when starting onthe trip.The Carpenter ants were under observation for about two

weeks when the queen laid a small cluster of yellow eggs eachnearly 2 mm. in length. These were a nice addition to therather large assortment of larvae which were taken with theadults and which we now see segregated to themselves in onecorner of the nest. The latter are white�just the color whichyou usually associate with grubs. Note that they vary greatlyin size; some are older than others and the different castes alsocause a size variation. The adult workers are almost alwaysnear them, licking them and feeding some of them atmost times. You ask about those buff colored objects about 7mm. long which we see in the other corner. They are commonlycalled ^ant eggs^ by those who do not distinguish between thedifferent stages; in reality, are cocoons enclosing pupae. Someare darker than others and we learn that this is due to age,


those having spun their cocoons only recently are light in colorwhile those about ready to emerge are decidedly darker inappearance. The latter have already assumed a certain amountof their pigmentation and it is this which shows through thepupal case. However, their full dark hue is not to be seen untilquite some time after they have emerged.You will be interested to know that in this colony we were

able to watch a larva spin its cocoon. If you want entertain-ment, observations such as these will furnish it�not to speakof the scientific angle of it. Competing closely with this processin the matter of attention-getting was the emergence of a cal-low from a cocoon. Three adult workers seemed definitely re-sponsible for seeing that this young lady made her entranceinto adult life in the proper manner. All of the other workerswere quite indifferent to the occasion, never came near thehalf opened cocoon. If one were ever tempted to use a humanemotion in describing ant behavior, he would have whilewatching the efforts of the three ants trying to extricate thefeeble callow out of her ^wrapper.n The whole process lastedfor close to an hour. Real cooperation between the workers wasnecessary to remove the envelope, two pulling at the callowand the other tugging at the cocoon.For the ants in the next nest, we should use our binocular

microscope for they are quite small and we shall be unable tosee much of their activities unless they are magnified. Peeringdown through the tubes we see a cluster of shiny bodies inter-locked and .intertwined about a central larger ant. Strong lightis thrown on the mass and enough of the small workers crawlaway to expose the wingless queen. They do not leave her en-tirely, seem to be so very careful lest she be subjected to someadverse condition that they prefer to linger in a closely packedgroup. These are Leptothorax longispinosus. They are ratherhard to find because they are so small that a thriving colonymay live in a tiny crevice, no larger than a pea, in an old golden-rod root.May I tell you about the first Leptothorax which I collected?

I had been out on a little field trip with my son and we hadbeen collecting a few of the large garden spiders which wereunusually abundant at the time. We had been looking at anenormous female entangle a grasshopper in her web when shesuddenly dropped to the ground. We were anxious to see herfeigning act and bent down under the weeds to find her. There


she lay, no sign of movement, just as though she were dead.But, I happened to catch a glimpse of some fine ^sawdust^ nearthe root of a goldenrod. Somehow I questioned it and decidedto try to find out what had caused it. Could it be the work ofants? The goldenrod plant, still in flower was uprooted and thisgave me the chance to see a small opening into the basal por-tion of the stem about an inch above the surface of the blackdirt. I cut into the stem and then split it lengthwise. There theywere, dozens of the little reddish ants, slightly over 2 mm. inlength. Thus another ambition was realized.One of the commonest ants in Chicagoland is Formica cinerea^

and we should not pass them by in our nest observations. Thethriving colony which we have upon our imaginary table wasremoved from a large mound about a foot in diameter andwhich stood about ten inches above the general level of thesurrounding ground. You see that there are several queens in it,which leads me to say that I at one time removed exactly 49queens from a similar mound. And, there were others left for Idid not completely obliterate the community. These ants arequite timid and are frequently attacked during the warm daysof July and August by the slavemakers, Formica Sanguined.The cinerea brood is taken, larva by larva, pupa by pupa, backto the nest ,of the raiders. This gives rise to a mixed colonysuch as we could demonstrate without much trouble. Theseants have other insects take advantage of them too. You maysee the small Histerid beetle in this nest, a true myrmecophile,which was taken along with the ants. They do not seem toobject to its presence; on the contrary they may be seen toregurgitate food to it. Food which should go to the brood byall that is right and proper. One could watch this comical re-lationship hour after hour. The beetle always gets regal treat-ment and one does not wonder that it is so content-lookingwhen in a large group of ants.

This particular colony of cinerea has been trained to movefrom one compartment of the large wooden nest to the otherwhen the chamber in which you desire them to be is darkened.This does not require a real ^training period^ for you willnotice that a new colony will remove to a dark place ratherquickly. By repeating the process a few times they seem toknow just what is expected and make the shift much morerapidly. This has very definite advantages since it allows oneto clean the compartment vacated and make other adjust-


ments which are necessary to the maintenance of the colony.Not only do the ants move from chamber to chamber in re-

sponse to the darkening, but they also take along some of theirtreasured possessions so that they may enjoy them in peace.For example, a large mealworm was cut into two pieces andplaced in the light chamber. Several workers clustered aboutthem and slowly tugged away until they had dragged them theentire length of the nest into the dark compartment. In thissame connection, there are usually a few rather recalcitrantants which do not seem to feel the urge to move into thedarkened chamber as promptly as the majority. These arepicked up bodily in the mandibles of some energetic workersand transported to the secluded chamber. When this activitybegins while you are watching the ants you hope that it willkeep on and on for it is thoroughly entertaining.To glance at some of the other nests momentarily would be

to see such interesting forms as Prenolepis, with the greatlydistended gasters, slowly waddling about with their onerousburden of sweet juices. And there we should see Lasius ameri-canus the small brown lawn ant, the commonest insect in theworld! What a large queen in comparison to the worker caste.The true ant pygmies could be seen in numbers, so small thatthey can turn about on the head of a pin. There would be dif-ferent stages in each, there would be a different sort of behaviorin each, and the mysteries of ant-life would soon be disclosed tous if we had time for thorough observations upon them. But thisis without the purpose of our little talk. We wanted to let youknow just a few of the experiences which are in store for you ifyou have never devoted any attention to the study of ants inyour laboratories.

For those who are anxious to have the opportunity of per-forming a number of serious experiments on ants, I shouldsuggest that you refer to the book Ants, Bees, and Waspsby Lubbock (Button). The classical American work is Antsby Wheeler (Columbia University Press). The lives of the greatmyrmecologists would be splendid outside reading for your stu-dents.

CORNELL RURAL SCHOOL LEAFLETHave you seen the November 1937 issue of the Cornell Rural School

Leaflet? Its title is, "Are They Vermin?" It is about hawks, owls, weasels,skunks, foxes, and other interesting members of the animal kingdom.

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ANT STUDY IN THE BIOLOGY CLASSROOM