A New Type of Artificial Nest for Ants and Termites

A New Type of Artificial Nest for Ants and Termites by S. H. SKAIFE Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 200...
Author: Cory Lang
1 downloads 0 Views 1MB Size
A New Type of Artificial Nest for Ants and Termites by

S. H.

SKAIFE

Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

INTRODUCTION.

The first account of an attempt to keep ants under observation in an artificial nest is that given by Jan Jacob Swammerdam in his remarkable book, Biblia Naturt2, published in 1753. His nest consisted of a large, flat dish with a strip of wax about three inches broad all round the edge. The wax was grooved to form a shallow moat holding water to prevent the escape of the insects. A thin layer of soil in the dish provided the ants with the means of burrowing and making their abode. The next naturalist to describe an artificial nest was the Swiss, Pierre Huber, who published the results of his studies of ants found in Switzerland in 1810. One type of nest he used consisted of a box mounted on legs: this was filled with soil and a large bell-jar was inverted over the whole. The ants placed in the apparatus burrowed in the soil and built up their mound of twigs and pine-needles under the bell-jar. It is obvious that, with such a contraption as this, little could be seen of what went on inside the nest. The other type of nest devised by Huber consisted of a wooden frame, twenty inches long and ten inches wide, by half an inch in thickness, with glass forming the two sides. The space so enclosed was divided into two equal flat compartments by a sheet of perforated tin placed between and parallel with the sheets of glass. The space between the tin and glass on each side was filled with soil in which the ants could burrow and make their nest. The frame was fixed vertically on a stand on the table and the food, honey and water, was introduced through an opening' in the top. Sir John Lubbock published his well-known "Observations on Ants. Bees and Wasps" between 1874 ano 1894. He combined Swammerdam's idea of a shallow moat to imprison the ants with a simplified version of Huber's nest. His nest consisted of two sheets of ordinary window glass about ten inches square, separated by a wooden frame from one-tenth to one-quarter of an inch in thickness, according to the size of the ants to be kept in the nest. By using a narrow wooden frame Lubbock did away with the need for the central partition of perforated tin. The space between the glass was filled with soil. These nests "were kept either in shallow boxes with loose glass covers resting on baize, which admitted enough air and yet was impervious to the ants; or on stands surrounded either by water or by fur with the hairs pointing downwards." The French naturalist, C. Janet, introduced quite a diffeerent type of nest in 1897. His nest, made of plaster of Paris, consists of an oblong block and the number and size of the chambers depending on the kind of ants to be kept in them. One of the chambers, at one end of the block, is

Skui!e:

.~rtificilll

alit and termite IIcst

45

left open and serves as a small reservoir in which water can be poured as required. The chambers in which the ants live have glass covers and the insects cannot escape from the nest. The Janet nest has been widely used and there are many modifications of it, most of which offer little if any improvement and do not overcome its basic disadvantages. Miss A. M. Fielde described her glass nests in 1900, which are similar in essentials to the Janet nest, but are made entirely of glass, the side walls consisting of glass strips glued to the base with crockery cement. In order to admit air Miss Fielde found it necessary to glue strips of Turkish towelling along the top of the glass strips. For moisture a thin piece of sponge was placed in each chamber, except the food chamber, and the sponge had to be moistened twice a week. E. Wassmann (1902), F. Santschi (1913), \,y. 1\1. Wheeler (1913), H. St. J. K. Donisthorpe (1927) and others have all described nests which are modifications of the above and all of which share their serious defects. Wilmon Newell. in his studies of the Argentine ant (1908), used the Lubbock type of nest, but with leather strips instead of wood as the side walls. He found that the shallow, narrow moat and the strips of fur recommended by Lubbock were quite useless as a means of confining these ants and he had to place his nests on stands in a trough of running water.

Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

THE DISADVANTAGES OF THESE NESTS.

For the past fifteen years I have tried most of the different types of nests mentioned above, but I have had to discard them all as unsatisfactory. My experience has been the same as Newell's (I.c.) with regard to the ineffectiveness of standing water or strips of fur as a barrier to ants. Standing water soon becomes covered with a fllm of dust and the ants can walk over it with ease, whilst the fur, even with the hair pointing downwards as recommended by Lubbock, fails completely to stop any ants I have tried from crossing it. H.unning water is effective, but the whole set-up is cumbersome and costly. Quite apart from the cost, it is neither pleasant nor easy to make observations whilst bending over a tank of running water. The great disadvantage of nests of the Janet type lies in the fact that the ants are kept close prisoners in a confined space, without access to the open air and consequently they do not behave normaIly. Argentine ants, for example, almost inYariably kill and cut up their queens after a few days in such a nest. No ants, so far as my experience goes, carryon their full, ordinary activities in such a nest; they may live in them for months or even years, but they are inactive and do little except loaf about inside the dark chambers of the nest. Nests of glass of the Lubbock and Fielde types have the added defect that drops of moisture condense on the inside of the glass; they are cold and unnatural and the ants escape from them at the first opportunity. What is required is a nest in which natural conditions are reproduced as closely as possible, yet in which the ants are under control and easily observed. They must have constant access to the open air, to soil and to

46

Journal cnt. Soc. S. Afriw: Vol. XlV., No.1. 31st May, 1951

water if they are to behave normally; they should also have ample room for exercise and be able to climb about on vegetation that is infested with aphides, meal ie-bugs and their kin. The apparatus should be simple, cheap and easily constructed. This is a formidable list of essentials, but I consider they are all adequately met in the new type of nest which I have devised after many trials and errors and which I have now been using successfully for some time.

Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

CORK LINO AND PLYWOOD.

My nests are of various sizes, from small single-celled nests in which young queens with their first brood are kept, to large many-celled nests for populous colonies. First of all a tray of the required size is constructed with a plywood base and strips of wood to form the sides and to stiffen the plywood base. The tray may be any convenient size, but it should be much larger than the nest it is to hold, because it provides the playground in which the ants can run about in the open air and hunt for their food. The nest itself consists of a sheet of ordinary cork lino of the requisite size, three-sixteenths or a quarter of an inch thick, with circular holes punched in it. This is best done by means of leather punches, of which I have three, making holes respectively three-quarters of an inch, one inch and one and a quarter inches in diameter. I find that these sizes answer all requirements, the three-quarter inch holes being suitable for small species of ants. whilst the one and a quarter inch holes are large enough for the biggest species. A sheet of cork lino nine inches by fourteen is just about the right size for a nest of forty-five cells, each an inch and a quarter in diameter. Such a sheet will comfortably take six rows of cells, rows of eight alternating with rows of seven cells as shown in fig. 2. The circular cells are connected with one another by cutting shallow grooves in the cork with a sharp knife. As a rule, I make only one exit to the exterior and this consists of a channel a quarter of an inch wide cut in the cork from the central cell of the outer row. It would be quite easy to cut holes of a suitable size to form the cells with a sharp knife, but the leather punches make a much neater job, and the regular rows of circular holes of the same size make it easy to keep track of the ants, to count them and their larvre and pupre if desired. to find the queens, and so on. Having prepared the cork lino it is now glued in position on the plywood base of the tray and for this purpose the modern plastic resin glue is most useful. Obtainable in powder form in tins, it needs only to be mixed with a little water for use; it sticks very firmly and when dry is quite water-proof. The underside of the lino is smeared with a thin layer of the glue and it is then laid in position on the tray, with a sheet of glass on top and then a couple of heavy books to hold it down quite flat whilst drying. As a cover to the nest, to exclude the light, I use thick felt cut to size.

:.-:

;z::::.

~

by Sabinet Gateway under licence granted by the Publisher (dated 2009).

~

Fig. 1.

~ '";.

~

.j.-

'I

Diagram of a small, six-celled nest, showing the arrangement of the screws and D.D.T. holders to confine the ants.

48

Journal enl. Soc .

s. Africa:

Vol. XlV., No.1. 31s1 .'v/ay, 1951

CONFINING THE ANTS.

Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

Now comes the problem of how to keep the ants from escaping from the .tray. Here again we ~re m~r~ fortunate than earlier workers in having available that very useful insectIcide, D.D.T. I simply screw four slender screws, one and a half inches long, in each corner of the underside or the tray, so that they project and form supports about an inch long. The tray then stands raised from the table on these four short legs.

to

Fig. 2. - Photograph of a forty-five-celled nest containing a colony of the blackmound termite, Amitermes atlanticus. The open-air arena contains moist humus and decayed wood.

As holders for the 10% D.D.T. powdel·, to prevent it from spreading over the table and contaminating everything, I use the metal bottle-tops known as crown corks. A little of the powder is sprinkled in four of these and they are placed under the screws so that each screw-head is surrounded with a layer of powder, as shown in fig. 1. With the tray insulated in this way the ants are effectively confined and no strange ants from outside can get on to the tray. When they are first put on the tray some of the ants, running wildly about, may drop on to the table and get lost, but the great majority soon learn to avoid the screws with the deadly powder at the base and they confine their wanderings to the upper surface of the tray. The powder retains its efficiency for months and only needs renewing at long intervals. INSTALLING THE ANTS.

It is quite easy to transfer a colony of ants from the veld to one of these nests. I f the ants nest in the soil, beneath stones or logs, the whole nest is dug up, soil and all, and put into a bag for carrying home. If they

Skaifc: Artificial ant and termite nest

49

make their nests in termite mounds, then that part of the mound containing the ants is broken off and put into a bag. If they live in carton nests or hollow stems it is a simple matter to carry the whole colony back to the laboratory. The ants and their brood are dumped on to the tray that has been prepared for them. In the case of ants that nest in soil or in termite mounds, they can be encouraged to enter the nest quickly by placing a little of their nesting material in each of the cells. The soil or powdered termite mound is moistened with a little water and then a small quantity of this is placed in each cell and pressed down firm and flat with a piece of wood so that it forms a layer about a sixteenth of an inch thick on the bottom of each cell. When the glass and felt cover are in place the ants quickly find their way into the darkened interior and instal themselves and their young there. In the case of ants that live in hollow stems, logs or carton nests, I usually paint the bottoms of the cells with red clay mixed with water to the consistency of cream. This quickly dries and is easily renewed as required and it forms a background against which the ants and their brood show up well. The plywood base outside the nest is in all cases painted with the same mixture or covered with a thin layer of fine soil; this is more natural than the bare wood and is better than ordinary paint. Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

WATER.

The exponents of the Janet and Fielde nests make much of the need for maintaining a moist atmosphere inside the artificial nests, hence the water reservoir of the Janet nests and the slices of sponge in the Fielde nests. But I do not find this necessary, even during the hot, dry summer months at the Cape, provided the ants have access to a constant supply of fresh water outside their nests. They are thirsty creatures and soon die if they cannot get water, but given a constant supply, they look after all their own moisture needs. A small dish kept filled with water is placed in one comer of each tray and the ants visit this regularly. FOOD.

Most ants seem to like a variety of food and to tire quickly of the same food placed before them day after day. Honey is eagerly accepted by most, but if they are given nothing but honey they neglect it after a time. Fresh killed insects, scraps of raw beef, ordinary cane sugar moistened with water, the larva! and pupae of other ants, and honey, all given more or less in rotation, will keep most colonies in a flourishing condition. Some ants will take sponge cake and scraps of ripe fruit. The mixture of raw yolk of egg, honey and sugar, recommended by Wheeler (1913), is also good. As is well known, many kinds of ants visit aphides, scale insects and others for the sake of their sugary excreta. I provide this type of food by transplanting small, infested plants into flower-pots and placing these on the trays so that the ants can run over them. If the infested plant is too

50

Journal ent. Soc. S. Africa,' Vol. XlV., No.1. 31st May, 1951

big for transplanting, I simply cut off a few twigs with the aphides on them and put them in a jar of water on the tray. Potatoes infested with mealie bugs are also placed on the trays. My experience has been that ants that habitually visit aphides in the field are greatly stimulated in my nests when they are given access to them in the manner described. MANIPULATION.

Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

For convenience in certain manipulations, I usually make the trays just twice the size of the nests they are to hold so that one half forms the open-air arena and the other half is occupied by the nest proper. If it is necessary to get at the inside of the nest, for cleaning purposes or to get specimens of the different stages, or for experimental purposes, then the felt and glass covers are simply lifted off and placed over the arena half of the tray. The ants quickly remove themselves and their young into the arena where it is clark. When the work on the inside of the nest is completed, the covers are put back again and the ants return to their home without loss or undue con fusion. Some of my nests are made in separate movable sections, each four and a quarter by three and a quarter inches; old Ciuarter-plate negatives with the gelatine cleaned off pro\·ide the glass covers for these sections. Such

Fig. 3. - Two cells of a nest containing Camponotine ants. These ants push their rubbish up into the crevice between the glass and the rim of the cells.

Skaife: .4.rtijicial ant and termite nest

51

.t '(

Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

,i

,.

Fig. 4. -

One cell, one and a quarter inches in diameter, of the nest containing A mite1"ms at/anticus, showing workers and the layer of mound material in the bottom of the cell.

sections are easily removed for examination uncler the binocular and ants can be transferred f rom one nest to another in order to watch their behaviour. Small numbers of ants can be removed from the colony at any time in one of these sections for various experiments and tests. TERMITES.

I have kept the black-mound termite, Amitennes allan-ficus, successfully in nests of this type . In their case I always" bait" the nest to get them to enter by putting a little of their powdered mound material, moi stened with water, in the bottom of each cell and pressing it down flat and firm as shown in Fig. 4. The mOllnd is then broken up and the termites are shaken out on to open half of the tray. The insects quickly find their way into the dark interior of the nest and settle down there. Then a layer of humus and decayed leaves and twigs is placed in the arena and this is kept

52

Journal enl. Soc. S. Africa: Vol. XIV., No.1. 31st May, 1951

constantly moist. The termites burrow through this layer and find their food and water there. After a few months the termites blacken the underside of the glass with their excreta so that it is impossible to see through it and it has to be removed for cleaning. The same procedure is adopted as that already described for the ants.

REFERENCES. Donisthorpe, H. St. J. K. (1927): "British Ants, their life history and classification", Geo. Routledge and Sons. Fielde, A. M. (900): II Portable Ants' Nests," BioI. Bull., Vol. 2, p. 81. Huber, P. (1810): .. Recherches sur les Moeurs des Fourmis indigenes," Paris et Geneve. Janet, C. (897): U Appareils pour l'Observation des Fourmis et des Animaux myrmecophiles," Mem. Soc. Zool., France, Vol. 10, p. 302. Lubbock, Sir John (1876 -1894): Original papers published in Jour. Linn. Soc. between these dates, republished in book form .. Ants, Bees and Wasps," revised ed. Intern. Sc. Series, N.Y. Appleton & Co., 1894. Newell, W. (1908): Notes on the Habits of the Argentine Ant, 1"idomyrmex humiZis,JJ Jour. Econ. Ent., Vol. I, p. 21. Santschi, F. (1913): Quoted in Wheeler (1913), p. 555. Swammerdam, J. J. (1753): .. Biblia Nature," Leyden. Wasmann, E. (1902): " Neues ueber die zusammengesetzen Nester und gemischten Kolonien der Amiesen," Algem. Zeitschr. Ent., Vol. 6, p. 353. Wheeler. W. M. (1913): .. Ants. their structure. development and behaviour," Columbia Univ. Press. p. 545.

Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2009).

U

Suggest Documents