Part I: Fundamental Part

Translator's Preface

Professor Bouvier is one of the well-known personalities in the scientific world of Paris. His tall, spare, distinguished form and his keen, intellectual face are seen at the ceremonies of the Institu...

Introduction

Insects are creatures which seem to defy the imagination with the strangeness of their form and their extraordinary habits. In the War of the Worlds, Wells the novelist surprises us with his bellige...

The Insect Does Not Belong To Our World

The other animals, even the plants, despite their mute existence and the great secrets which they nourish, do not seem wholly strangers to us. In spite of all we share with them a certain feeling of t...

Chapter I. Directive Action Of Light: Phototropism. The Pyralids Of Pliny

In the eleventh volume of his Natural History, Pliny the elder tells a strange story. In the forges of Cyprus, he says, one sees a large four-legged fly flying in the midst of the flames. Some ca...

Directive Orientation Toward The Light: Positive Phototropism

The observation of Pliny has passed into current practice. For a long time light traps have been used to capture the destructive Vine Pyralis and it is with traps of this kind or with simple lanterns ...

Directive Orientation Away From The Light; Negative Phototropism

All animals are not equally sensitive to light; many do not appear to be phototropic, others are very slightly so, and the degree of attraction grows less and less until a good many direct themselves ...

Character Of Phototropism

Be it positive or negative, phototropism appears to us as a purely physical directive reaction; that is to say, innate, automatic, independent of all choice and consequently of all psychic phenome...

The Phototropic Animal Is Not Guided By Choice, It Acts Like An Automaton

In the presence of two sources of light, says Georges Bohn, it orients itself toward neither the one nor the other, but in an intermediate direction, so that the two sides of its body receive the same...

Physical Interpretation Of Phototropism

Jacques Loeb has given the following interpretation of these phenomena: When the rays coming from a luminous center strike asymmetrically one side of the sensitive region (the head with the articulate...

Physicochemical Interpretation Of Phototropism

It may be said that the preceding interpretation is a simple statement of facts. But Loeb has not contented himself with the establishment of a formula; he has wished to establish the relations which ...

Other Factors Which May Modify The Phototropism

If this be so, one conceives that, aside from light, phototropism may be modified by all the factors, either external or internal, which are capable of acting on the photochemical substances of the or...

Chapter II. The Different External Stimuli And The Tro-Pisms Which They Provoke

Organisms respond automatically to the luminous stimulus with an orientation and with determined movements. Whether they are provided with eyes or not, they react the same, and this reaction is not th...

Action Of Heat: Thermotropism

Heat is the result of molecular vibrations which increase in number in proportion as the temperature rises. We know that it is one of the principal agents of all chemical phenomena. In different ways ...

Action Of Humidity: Hydrotropism

No less than heat, water is necessary to living beings, for it constitutes the greater portion of their protoplasm and plays a part in almost all their internal changes. Also, all organisms are sensit...

Action Of Chemicals: Chemotropism

Protoplasm is not less sensitive to chemical agents; but its changing and complex nature varies according to the species and its response to the chemical excitant varies also. This response is again a...

Action Of Gravity: Geotropism

Gravity acts on the protoplasm by its tendency to separate heavy substances from less dense elements. But, contrary to the ideas of Verworn, Davenport does not believe that this action is purely mecha...

Actions Of Contact

Contacts and the pressure that results may irritate the protoplasm and, at least by contraction or extension, modify the physiological state of its substance. When contacts are produced by currents o...

General Observations On Tropisms. Association Of Tropisms Among Themselves

In the normal environment in which they live, organisms are almost always, if not always, subject to different external stimulations to which they may be more or less sensitive. They are therefore sub...

Association Of Tropisms With Other Activities

On account of the irritability of living matter, we understand the sensitiveness which makes organisms respond to the excitation of stimuli and to react to them by movements and by more or less comple...

Character Of Tropisms

It may be said, of tropisms in general, as we have said of phototropism in particular, that they are automatic and, so far as they distinguish sensations, independent of any choice and consequently of...

Chapter III. Vital Rhythms And The Organic Memory

What influence is exerted upon the organism by external -stimuli which make themselves felt at regular periods? That is what we are going to study in the present chapter. The Paradox Of Reaumur; Diur...

Interpretation Of This Periodicity

Davenport interprets the experiments of Loeb and of Reaumur by saying that the diurnal butterflies are so constructed that they react only to a high luminous intensity, and the nocturnal moths to a fe...

The Actual Acquisition Of A Diurnal Periodicity

That this is really so-that is to say, that the diurnal periodicity of butterflies has been acquired in the course of their history-is what the pretty experiments of Eoubaud1 have shown concerning the...

Other Examples Of Diurnal Periodicity

Many insects besides butterflies possess a periodicity which responds to the alternation of day and night. Most of the Hymenoptera are diurnal, among others the bees and the wasps. The predatory insec...

Convoluta And Littorina

All natural rhythms can develop an acquired periodicity in organisms. We know the suggestive observations of Bohn on the marine worms of the genus Convoluta which are found in masses on certain sandy ...

The Misanthropic Pagurus

Analogous phenomena have been observed by Drzewina (1907), in the charming little hermit crab of our coasts, the misanthropic Pagurus (Clibanarius misanthropus), which is found in abundance upon the l...

Other Rhythms

Periodic phenomena are common in organisms, from plants which show them by the diurnal or nocturnal attitudes of certain species, up to the human species and certain mammals, where they appear in the ...

Acquired Periodicity And Dependent Periodicity

From a consideration of these phenomena, which have not been studied enough, it seems rather certain that acquired periodicity-that is to say, innate-has as an antecedent a dependent periodicity close...

Organic Memory

Thus natural rhythms produce more or less profound periodical modifications in the organism. This periodicity leaves, in the long run, a trace in the tissues. It becomes engraved there and ends by man...

Chapter IV. Differential Sensitiveness

What characterizes tropisms is a directive orientation which automatically leads the organism in the same axis of the stimulating force, this being invariable as long as the stimulation lasts. What wi...

Relations Between The Differential Response And The Understanding Of Tropism

As we have just seen, it is by the responses of the organism to the variations of luminous intensity that work concerning differential sensitiveness began, and the responses to these variations have b...

Relations Between The Differential Response And The Understanding Of Tropism. Continued

To make the currant-worms give characteristic responses of differential sensitiveness, it is not necessary to put them in the presence of a shadow zone. If we bend the horizontal supporting plane a li...

Combination Of Differential Sensitiveness With The Tropisms

As we have just seen, differential sensibility is subject to a certain number of laws which essentially distinguish it from tropisms, and on the other hand it is closely linked with them. Most often t...

Chapter V. Differential Sensitiveness-Species Memory, And Simulation Of Death. The Theory Of Trial And Error

The numerous and interesting experiments carried on by Jennings1 to justify the theory of trial and error furnish striking examples of the combination of tropisms with the phenomena of differential se...

Possible Adaptation Of Differential Sensitiveness

If it is not necessary to see in the actual phenomena of differential sensitiveness a series of trials which rectify the errors, and if one considers the stops, turnings, and recoils which characteriz...

Species Memory

The trials of apprenticeship! Here we are, it seems, brought to Jennings's theory, which we have immediately judged to be untenable, at least in the cases and in the form in which it has been presente...

Simulation Of Death

Among the reactions produced by differential sensibility which strike us first is the sudden immobilization, the abrupt stopping, of the insect experimented with. This inmobility is commonly short, ra...

Fabre's Experiments

Let us study this curious phenomenon more closely and let us first follow the experiments carried on at Serignan by J. H. Fabre. There is a predatory beetle, nocturnal in its habits (Scarites gigas),...

Fabre Made Similar Experiments With Other Insects

The results vary according to the species.. The little Scarites lœvigatus, although closely related to the former species, remained motionless only a few minutes. The big buprestid Capnodis tenebrioni...

Characters Which Approach Simulation With Phenomena Of Differential Sensitiveness

As Bohn has shown, the preceding phenomena seem tributary to differential sensitiveness. At first they manifest themselves identically under the influence of variations of a stimulant, whatever this s...

Mechanism And Nature Of The Simulation

This parallel need not be pushed too far, because the mechanism and the physical nature of simulation present special characters. Let us note first the muscular tetanus which gives to articulates in ...

Biological Significance

If it is not doubtful that the simulation is a phenomenon of differential sensitiveness, limited to cataleptic tetanus, and characterized by it, we must admit that its biological significance is still...

Chapter VI. Individual Or Associative Memory

The phenomena so far studied manifest themselves in the lowest animals, in many plants, even also in the highest representatives of the animal kingdom. They cannot be related closely to nervous difïer...

Manifestations Of Individual Memory

Fabre tells us the story of the Languedoc sphex (Sphex occitano) a kind of wasp that hunts the grasshoppers of the genus Ephippigera for its progeny, stings them under the thorax and paralyzes them, a...

Apprenticeship

The experiments of Ferton show us that the memory of the Osmias is facile, but, that it is not of the same degree in all species. A single exploration suffices Osmia rufohirta to learn to know well th...

Individual Or Associative Memory

Experimentation has not so far played a sufficient part in the biological study of the invertebrates and it will not be easy to bring together many examples similar to the preceding, nor as good ones....

Passage To Automatism

This last point deserves our attention, for it is one of the dominant characters of the psychology of insects. With these animals, in fact, certain sensations rapidly impress themselves on the nerve c...

Rules Of Individual Memory

Certain sensations may be so acute that for the moment they destroy all others. This phenomenon is not rare in man,- as witness absorbed persons. It is commoner still with the arthropods and plays a...

Chapter VII. Spontaneous Modifications Of Habits

Here we find ourselves in the presence of two kinds of activities which at first seem very dissimilar,-those which all the representatives of a species produce without actual apprenticeship, and those...

Observations Of Fabre

I will first invoke testimony which cannot be impugned,-that of Fabre, an intense believer in the changelessness of instincts. The venerable biologist says : Pure instinct, if it'existed alone, would...

Observations Of Ferton

Of all the biologists who have devoted themselves to the habits of insects, Ferton is surely one of the most precise. Sagacious and penetrating, he submits his observed facts to a very severe analysis...

Perez And The Osmias

The lamented Professor Perez was the teacher of Ferton. He had the same ideas and his biological observations were of the same thorough character. His observations on the variability of the instincts ...

The Philanthus Wasps

In investigations of this kind it is necessary to know how to concentrate one's effort and to follow the actions of a species in their slightest details. No discipline is less harsh, for the life of t...

The Urn-Making Ammophila

In the course of the long and very able studies which they devoted to the biological investigations of the solitary wasps, George and Elizabeth Peckham1 have shown numerous individual variations in th...

Chapter VIII. Evolution Of Instincts. Modification Of Instincts By The Inheritance Of Acquired Habits

From the facts which we have just recited we may conclude that insects are individually capable of modifying their habits, and the experiments cited in the preceding chapter prove that they can acquir...

The Lamarckian Law Of Heredity

The experiments which we have just described are almost all very recent, and they will have to be added to somewhat, but they establish the fact that insects acquire new habits very quickly and that t...

Modifications Of Instincts By Mutations

The chemical modifications of the organism are due principally to the exercise of the muscles, of the digestive tube, of the nervous system,-in a word, the different tissues which one qualifies as som...

Atavism

From the preceding facts we can conclude, contrary to the disciples of Weismann or the neo-Darwinians, that instincts may be modified by the hereditary transmission of slowly acquired habits, and, con...

A Retrospective Glance

Whether they are the result of acquired characters or come from mutations, the innate and automatic acts which we have just studied are characterized by the fact that they are always supposed to have ...

Chapter IX. Comparative Psychology. History Of The Pompilids

The present is really a continuation of the preceding chapter. If it is true- that instincts are modified nowadays by the hereditary adding of new habits, it must be admitted that they were modified i...

The Pompilids Are Hunters Of Spiders

Active and enterprising, they know how to escape the venomous fangs of their redoubtable adversaries, which they chase and paralyze before carrying them to their place of nesting. This having been don...

The Prey Captured

On this subject we should first listen to Ferton, who more than any one else has studied the habits of the pompilids. After having observed that the size of the victims captured by each species cannot...

Treatment Of The Victims

As soon as captured the victim receives the poisonous sting of the hunter. With the pompilids, as with the other paralyzing Hymenoptera, the employment of the sting, according to Fabre, cannot be acco...

Relations Of The Egg And The Larva With The Host

The egg of the pompilid is always attached to the abdomen, on the back or on the sides, and when the victim is caught upside down, which is rare (Agenia), on the ventral side. As to the larva which co...

The Arrangement Of The Nest

Certain pompilids make no nest. Aporus bicolor deposits its prey in a crevice, and Evagetes laboriosus in a shell or in a cleft in the ground; others, like the buffoon Calicurgus, scratch some bits of...

The Parasitic Pompilids

There are, as a matter of fact, some pompilids which, instead of hunting, lay their eggs upon the victim which their congeners carry to the nest. The first observations concerning this change of habit...

The Origin Of Parasitism With The Pompilids

It is, then, certain that some pompilids do not hunt, do not paralyze, do not nest, and yet assure the future of their progeny by ravaging others of the benefit of their work. How can such an inversio...

Part II: Special Part

Special Part

We have limited ourselves so far to the study of the essential phenomena by which the activity of the entomological world manifests itself to the observer, and our study has brought us to rules which ...

Chapter X. Insects And Flowers. Anthophilous Insects

We have become accustomed to call insects which are attracted to flowers anthophilous. Almost all of the anthophilous insects belong to the highest groups of the entomological fauna,- to those whose ...

The Choice Of Flowers

The anthophilous insects do not visit all flowers indifferently. In the conrse of an entomological excursion in which I had as a companion the very learned Professor Giard, we made a large collection ...

The Choice Of Flowers. Continued

These observations become especially interesting when they are applied to the social bees. Our honey-bee, for example, is incapable of getting the nectar from narrow flower tubes whose depth exceeds s...

(1) Attraction To Colors

The Peckhams relate that, having placed some red nasturtiums upon a yellow background near a wasps' nest, they saw that the insects flew to the flowers before their return to the nest, while they pass...

(2) Influences Combined With Color And With Form

Here is a herbage-covered slope where here and there shine out the white flowers of the bindweed of the fields. A butterfly of the genus Pieris flits among these flowers, and with undulating flight mo...

(3) Influence Of Floral Odors

It is well known that bees and many other flower-visiting insects are accustomed to visit a certain kind of flower at certain times and at those times to neglect other kinds. This habit places before ...

Role Of The Psychic Faculties In The Search For Flowers

Forel has justly observed that if insects are guided by a principal directive sense the rule is always that they associate the impressions of several senses. Capable of attention, endowed with memor...

On Reciprocal Adaptation

We know now that flowers are indispensable to the greater number of anthophilous insects, and we know on the other hand, from the researches of Darwin, that insects are necessary to a great number of ...

Trap Plants

We have for a, long time given the name trap plants to a certain number of Asele-piads and Zingïberaceœ whose flowers are so made that they often hold in fatal captivity the insects that visit them. K...

Chapter XI. The Faculty Of Orientation

How do insects orient themselves when proceeding to a place which is more or less distant? Are they simply reflex machines, as Bethe says? Or are they guided by a special directive sense, as Fabre bel...

Perceptible Objective Point

Chance plays a predominant role in the two essential activities of insects, the search for nourishment and the sexual approach. It leads the animal to places in which the objective becomes capable of ...

Non-Perceptible Objective; Migrations

There are cases where the insect reaches an unknown objective guided by a series of intermediary excitants. As Claparède observes, these cases approach the preceding ones, because each intermediary d...

Aerial, Or Flying, Insects

This observation by the clever entomologist seems surely to show that sight and a memory of places play a large part in the orientation of flying insects. We know, moreover, that these insects are inc...

The End Is Perceptible

Whatever may be the manner in which insects direct their journeys, there comes a time when the place which they are seeking becomes perceptible. How is it, then, that they get to this point 1 It is, ...

Non-Perceptible End With Or Without Intermediary Guiding Points

We know now that flying insects, once in sight of the spot where their nest is established, find the orifice of the latter by means of visual sensations fixed in their memory. It now remains to know t...

Chapter XII. The Faculty Of Orientation With Terrestrial Articulates. Different Articulates

Aside from insects, we know only a little about orientation with terrestrial articulates. That is why it will be interesting to report the following observation concerning Agelena labyrinthica, a very...

Orientation With The Ants

Not less surprising is this conclusion of Fabre, who admits the faculty of scouting to walking insects whose horizon is necessarily restricted, while he refuses it to Chalicoderma and to Cerceris,-tha...

(2) Interpretation Of These Rules

Such are the important rules established by Piéron and Cornetz. It remains now to interpret them. What determines the direction of the explorer is the object of going; but how can an explorer preserv...

Interpretation Of These Rules. Continued

Viehmeyer on the one hand and Turner on the other have arrived at the same result by different methods. Viehmeyer (1900) reared Leptothorax unifasciatus which had established their nest in earth in th...

(3) Turner's "Circling"

During the second part of their journey, that of their return, the workers march in perfect order toward the nest, in a straight line or one parallel to the line of coming out (Figure 14), without the...

Estimation Of Distance

The experiment of Piéron (page 256) shows that the sensorial excitants are not the direct cause of the circling. Transported to a distance, the insect follows a path parallel to the first direction, a...

Upon The Ant Roads

To reach the exploitation field where they find food, many ants follow visible and well-traced routes which radiate around their nest. .These routes are commonly rather broad near the orifice, sometim...

The Establishment Of A Road

According to Forel, this is how the Amazons (Polgergus rufes-cens) go to the nest of Formica rufa, situated often from forty to sixty meters away and quite hidden. In the springtime and in the summer...

Behavior Of Ants On Their Roads

The antennal senses (tactile, and especially olfactory) play a predominant part in guiding ants on their roads. We already know that the Amazons are incapable of following, when the antennae have been...

Direction Followed Upon A Scent

Not only do ants know how to direct themselves by scent, but they distinguish it in the sense of going and coming. Upon a scent which had served at their colony-moving, Formica pratensis went back and...

Chapter XIII. The Division Of Sexes With Nest-Making Hymenopteka

The females of certain insects may be fertile without coupling, and then produce eggs which have not been subjected to spermatozoal fecundation. When this phenomenon' is accidental, as happens sometim...

Division Of Sexes With The Social Hymenoptera

;The preceding rules do not apply to the social Hymenoptera,-bees, wasps, and ants. With these insects each colony is a numerous family in which all the individuals are common offspring procreated by ...

Occasional Fertility Of The Neuters

The neuter females are incapable of coupling; provided with reduced genital organs, they can reproduce, in certain cases, hut then lay male eggs exclusively. Although disputed by Perez., this 'phenom...

Division Of The Sexes Among The Bees

But in a hive in good condition, male eggs do not come from the workers ; they are laid by the queen, who places them in appropriate cells longer and larger than the others. And this suggests the ques...

(1) The Male Eggs Are Not Fertilized

The theory clears up perfectly phenomena which had hitherto seemed inexplicable. It was already believed that the ovarian tubes contained male eggs and female eggs. Having realized that the queen lays...

(2) Selective Power Of The Queen In The Division Of The Sexes

We arrive now at the second principle. Is it true, as Wasmann contends, that the queen lays at will eggs of one or the other sex, that she voluntarily fertilizes certain eggs, and that she places the ...

Division Of Sexes With The Social Wasps

We know that the social wasps differ from the honeybee in that their large cells are reserved for the true females, while the little ones are intended for the rearing of the males and of the sterile f...

Solitary Hymenoptera

We know very little about the division of sexes in the other social Hymenoptera, the Meliponas, the bumblebees, and the ants. On the other hand, this subject has been admirably studied by Fabre with n...

Mechanism Of The Phenomena

But is it true, as Fabre thinks, that to be able to give to each larva the space and the nourishment which belong to it, whether it is male or female . . . the female should know the sex of the egg w...

The Rhythm In The Laying

To ascertain whether or not the division of the sexes with the solitary nesting species is effected according to a rhythm, it is necessary to observe the insect in full liberty. This is what Fabre ha...

General Conclusions

If it be true, as we cannot doubt, that the social Hymenoptera are derived from solitary species, we can imagine that the evolution of the curious instincts which are shown in the two groups in the di...

Chapter XIV. The Social Life Of The Akticulates

Like most animals, the articulates are, above all, individualists: they work for themselves without aid from their brothers, and their existence seems to have no other end than self-protection. Some, ...

Individual Societies Of Akticulates

When the animals find a place favorable to their vital needs, they establish themselves there in small colonies and live side by side without bothering about their neighbors. Thus do the Ocypodes, the...

Communistic Societies Of Akticulates

The communistic societies obey the same laws as the preceding, but they are more rigorous in the family groupings, for they presuppose the young to be born by the side of their parents. When these you...

Societies Of Termites

Indeed, we do not know the primitive stages of the social life with those Pseudo-Neuroptera which are known by the wrong name of white ants, and which constitute the great family of Termitidce. All th...

Societies Of Ants

With the ants, as with all the communistic Hymenoptera, there is a fertile female or queen (sometimes several) upon which devolves the reproductive functions; the males die after coupling, leaving to ...

Societies Of Mellifera

It seems that an abyss, from the social point of view, separates the solitary bees from our domestic honey-bee, with which the division of work is so perfect ; but comparative biology permits us to br...

Wasp Societies

With the social wasps as with the higher bees, the egg is laid singly in the still empty cell, and the food of the larvae is given them day by day. But this food is composed of fragments of fresh prey...

Factors Common To All The Social Groups

It appears from what precedes that the social life is found in very different groups and with groups which are very diverse from the psychic point of view. This form of life is, then, equally independ...

Other Factors Contribute To Hold These New-Born To The Nest

Roubaud observed that the young females of Belonogaster remain in the nest for eight days and during this time receive the nutritive morsels which they chew and distribute among the larva? after havi...

Founding Of Communistic Societies

If it be true, as we cannot doubt, that social insects have developed from solitary ancestors, there is reason to believe that communistic societies were originally monogamous, that is to say establis...

Origin Of Castes In Communistic Societies

However it may be, the nests of termites, of bumblebees, of ants, and of most of the wasps are always established by royal couples which at the start must satisfy all the needs of the budding society....

Communistic Societies Are Super-Organisms

It is the presence of workers which gives communistic societies their highest degree of perfection, for it is that which allows the greatest division of labor and which establishes between the members...

Conclusion

In current language the word instinct is used for all the hereditary and automatic manifestations of activity, from tropisms to the most complicated outward manifestations of individual memory. Inst...

Instincts Are Diverse

If we class under the name instinct not one special faculty but the ensemble of all instincts, that is to say, innate automatism, whatever its origin may be, we may say with Bergson that instinct and ...

Instincts Are Diverse. Continued

Man occupies the highest point in the vertebrate scale, for he breaks the chain of instincts and thus assures the complete expansion of his intellect. The insects, especially Hymenoptera, hold the sam...