THE HALICTI PARTHENOGENESIS
The Halictus opens up another question, connected with one of life's
obscurest problems. Let us go back five-and-twenty years. I am living
at Orange. My house stands alone among the fields. On the other side
of the wall enclosing our yard, which faces due south, is a narrow
path overgrown with couch-grass. The sun beats full upon it; and the
glare reflected from the whitewash of the wall turns it into a little
corner, shut off from the rude gusts of the north-west wind.
Here the Cats come to take their afternoon nap, with their eyes half-
closed; here the children come, with Bull, the House-dog; here also
come the haymakers, at the hottest time of the day, to sit and take
their meal and whet their scythes in the shade of the plane-tree;
here the women pass up and down with their rakes, after the hay-
harvest, to glean what they can on the niggardly carpet of the shorn
meadow. It is therefore a very much frequented footpath, were it only
because of the coming and going of our household: a thoroughfare ill-
suited, one would think, to the peaceful operations of a Bee; and
nevertheless it is such a very warm and sheltered spot and the soil
is so favourable that every year I see the Cylindrical Halictus (H.
cylindricus, FAB.) hand down the site from one generation to the
next. It is true that the very matutinal, even partly nocturnal
character of the work makes the insect suffer less inconvenience from
The burrows cover an extent of some ten square yards, and their
mounds, which often come near enough to touch, average a distance of
four inches at the most from one another. Their number is therefore
something like a thousand. The ground just here is very rough,
consisting of stones and dust mixed with a little mould and held
together by the closely interwoven roots of the couch-grass. But,
owing to its nature, it is thoroughly well drained, a condition
always in request among Bees and Wasps that have underground cells.
Let us forget for a moment what the Zebra Halictus and the Early
Halictus have taught us. At the risk of repeating myself a little, I
will relate what I observed during my first investigations. The
Cylindrical Halictus works in May. Except among the social species,
such as Common Wasps, Bumble-bees, Ants and Hive-bees, it is the rule
for each insect that victuals its nests either with honey or game to
work by itself at constructing the home of its grubs. Among insects
of the same species there is often neighbourship; but their labours
are individual and not the result of co-operation. For instance, the
Cricket-hunters, the Yellow-winged Sphex, settle in gangs at the foot
of a sandstone cliff, but each digs her own burrow and would not
suffer a neighbour to come and help in piercing the home.
In the case of the Anthophorae, an innumerable swarm takes possession
of a sun-scorched crag, each Bee digging her own gallery and
jealously excluding any of her fellows who might venture to come to
the entrance of her hole. The Three-pronged Osmia, when boring the
bramble-stalk tunnel in which her cells are to be stacked, gives a
warm reception to any Osmia that dares set foot upon her property.
Let one of the Odyneri who make their homes in a road-side bank
mistake the door and enter her neighbour's house: she would have a
bad time of it! Let a Megachile, returning with her leafy disk in her
legs, go into the wrong basement: she would be very soon dislodged!
So with the others: each has her own home, which none of the others
has the right to enter. This is the rule, even among Bees and Wasps
established in a populous colony on a common site. Close
neighbourhood implies no sort of intimate relationship.
Great therefore is my surprise as I watch the Cylindrical Halictus'
operations. She forms no society, in the entomological sense of the
word: there is no common family; and the general interest does not
engross the attention of the individual. Each mother occupies herself
only with her own eggs, builds cells and gathers honey only for her
own larvae, without concerning herself in any way with the upbringing
of the others' grubs. All that they have in common is the entrance-
door and the goods-passage, which ramifies in the ground and leads to
different groups of cells, each the property of one mother. Even so,
in the blocks of flats in our large towns, one door, one hall and one
staircase lead to different floors or different portions of a floor
where each family retains its isolation and its independence.
This common right of way is extremely easy to perceive at the time
for victualling the nests. Let us direct our attention for a while to
the same entrance-aperture, opening at the top of a little mound of
earth freshly thrown up, like that accumulated by the Ants during
their works. Sooner or later we shall see the Halicti arrive with
their load of pollen, gathered on the Cichoriaceae of the
Usually, they come up one by one; but it is not rare to see three,
four or even more appearing at the same time at the mouth of one
burrow. They perch on the top of the mound and, without hurrying in
front of one another, with no sign of jealousy, they dive down the
passage, each in her turn. We need but watch their peaceful waiting,
their tranquil dives, to recognize that this indeed is a common
passage to which each has as much right as another.
When the soil is exploited for the first time and the shaft sunk
slowly from the outside to the inside, do several Cylindrical
Halicti, one relieving the other, take part in the work by which they
will afterwards profit equally? I do not believe it for a moment. As
the Zebra Halictus and the Early Halictus told me later, each miner
goes to work alone and makes herself a gallery which will be her
exclusive property. The common use of the passage comes presently,
when the site, tested by experience, is handed down from one
generation to another.
A first group of cells is established, we will suppose, at the bottom
of a pit dug in virgin soil. The whole thing, cells and pit, is the
work of one insect. When the moment comes to leave the underground
dwelling, the Bees emerging from this nest will find before them an
open road, or one at most obstructed by crumbly matter, which offers
less resistance than the neighbouring soil, as yet untouched. The
exit-way will therefore be the primitive way, contrived by the mother
during the construction of the nest. All enter upon it without any
hesitation, for the cells open straight on it. All, coming and going
from the cells to the bottom of the shaft and from the shaft to the
cells, will take part in the clearing, under the stimulus of the
It is quite unnecessary here to presume among these underground
prisoners a concerted effort to liberate themselves more easily by
working in common: each is thinking only of herself and invariably
returns, after resting, to toil at the inevitable path, the path of
least resistance, in short the passage once dug by the mother and now
more or less blocked up.
Among the Cylindrical Halicti, any one who wishes emerges from her
cell at her own hour, without waiting for the emergence of the
others, because the cells, grouped in small stacks, have each their
special outlet opening into the common gallery. The result of this
arrangement is that all the inhabitants of one burrow are able to
assist, each doing her share, in the clearing of the exit-shaft. When
she feels fatigued, the worker retires to her undamaged cell and
another succeeds her, impatient to get out rather than to help the
first. At last the way is clear and the Halicti emerge. They disperse
over the flowers around as long as the sun is hot; when the air
cools, they go back to the burrows to spend the night there.
A few days pass and already the cares of egg-laying are at hand. The
galleries have never been abandoned. The Bees have come to take
refuge there on rainy or very windy days; most, if not all, have
returned every evening at sunset, each doubtless making for her own
cell, which is still intact and which is carefully impressed upon her
memory. In a word, the Cylindrical Halictus does not lead a wandering
life; she has a fixed residence.
A necessary consequence results from these settled habits: for the
purpose of her laying, the Bee will adopt the identical burrow in
which she was born. The entrance-gallery is ready therefore. Should
it need to be carried deeper, to be pushed in new directions, the
builder has but to extend it at will. The old cells even can serve
again, if slightly restored.
Thus resuming possession of the native burrow in view of her
offspring, the Bee, notwithstanding her instincts as a solitary
worker, achieves an attempt at social life, because there is one
entrance-door and one passage for the use of all the mothers
returning to the original domicile. There is thus a semblance of
collaboration without any real co-operation for the common weal.
Everything is reduced to a family inheritance shared equally among
The number of these coheirs must soon be limited, for a too
tumultuous traffic in the corridor would delay the work. Then fresh
passages are opened inwards, often communicating with depths already
excavated, so that the ground at last is perforated in every
direction with an inextricable maze of winding tunnels.
The digging of the cells and the piercing of new galleries take place
especially at night. A cone of fresh earth on top of the burrow bears
evidence every morning to the overnight activity. It also shows by
its volume that several navvies have taken part in the work, for it
would be impossible for a single Halictus to extract from the ground,
convey to the surface and heap up so large a stack of rubbish in so
short a time.
At sunrise, when the fields around are still wet with dew, the
Cylindrical Halictus leaves her underground passages and starts on
her foraging. This is done without animation, perhaps because of the
morning coolness. There is no joyous excitement, no humming above the
burrows. The Bees come back again, flying low, silently and heavily,
their hind-legs yellow with pollen; they alight on the earth-cone and
at once dive down the vertical chimney. Others come up the pipe and
go off to their harvesting.
This journeying to and fro for provisions continues until eight or
nine in the morning. Then the heat begins to grow intense and is
reflected by the wall; then also the path is once more frequented.
People pass at every moment, coming out of the house or elsewhence.
The soil is so much trodden under foot that the little mounds of
refuse surrounding each burrow soon disappear and the site loses
every sign of underground habitation.
All day long, the Halicti remain indoors. Withdrawing to the bottom
of the galleries, they occupy themselves probably in making and
polishing the cells. Next morning, new cones of rubbish appear, the
result of the night's work, and the pollen-harvest is resumed for a
few hours; then everything ceases again. And so the work goes on,
suspended by day, renewed at night and in the morning hours, until
The passages of the Cylindrical Halictus descend to a depth of some
eight inches and branch into secondary corridors, each giving access
to a set of cells. These number six or eight to each set and are
ranged side by side, parallel with their main axis, which is almost
horizontal. They are oval at the base and contracted at the neck.
Their length is nearly twenty millimetres (.78 inch.--Translator's
Note.) and their greatest width eight. (.312 inch.--Translator's
Note.) They do not consist simply of a cavity in the ground; on the
contrary, they have their own walls, so that the group can be taken
out in one piece, with a little precaution, and removed neatly from
the earth in which it is contained.
The walls are formed of fairly delicate materials, which must have
been chosen in the coarse surrounding mass and kneaded with saliva.
The inside is carefully polished and upholstered with a thin
waterproof film. We will cut short these details concerning the
cells, which the Zebra Halictus has already shown us in greater
perfection, leave the home to itself and come to the most striking
feature in the life-history of the Halicti.
The Cylindrical Halictus is at work in the first days of May. It is a
rule among the Hymenoptera for the males never to take part in the
fatiguing work of nest-building. To construct cells and to amass
victuals are occupations entirely foreign to their nature. This rule
seems to have no exceptions; and the Halicti conform to it like the
rest. It is therefore only to be expected that we should see no males
shooting the underground rubbish outside the galleries. That is not
But what does astonish us, when our attention is directed to it, is
the total absence of any males in the vicinity of the burrows.
Although it is the rule that the males should be idle, it is also the
rule for these idlers to keep near the galleries in course of
construction, coming and going from door to door and hovering above
the work-yards to seize the moment at which the unfecundated females
will at last yield to their importunities.
Now here, despite the enormous population, despite my careful and
incessant watch, it is impossible for me to distinguish a single
male. And yet the distinction between the sexes is of the simplest.
It is not necessary to take hold of the male. He can be recognized
even at a distance by his slenderer frame, by his long, narrow
abdomen, by his red sash. They might easily suggest two different
species. The female is a pale russet-brown; the male is black, with a
few red segments to his abdomen. Well, during the May building-
operations, there is not a Bee in sight clad in black, with a
slender, red-belted abdomen; in short, not a male.
Though the males do not come to visit the environs of the burrows,
they might be elsewhere, particularly on the flowers where the
females go plundering. I did not fail to explore the fields, insect-
net in hand. My search was invariably fruitless. On the other hand,
those males, now nowhere to be found, are plentiful later, in
September, along the borders of the paths, on the close-set flowers
of the eringo.
This singular colony, reduced exclusively to mothers, made me suspect
the existence of several generations a year, whereof one at least
must possess the other sex. I continued therefore, when the building-
who was over, to keep a daily watch on the establishment of the
Cylindrical Halictus, in order to seize the favourable moment that
would verify my suspicions. For six weeks, solitude reigned above the
burrows: not a single Halictus appeared; and the path, trodden by the
wayfarers, lost its little heaps of rubbish, the only signs of the
excavations. There was nothing outside to show that the warmth down
below was hatching populous swarms.
July comes and already a few little mounds of fresh earth betoken
work going on underground in preparation for an exodus in the near
future. As the males, among the Hymenoptera, are generally further
advanced than the females and quit their natal cells earlier, it was
important that I should witness the first exits made, so as to dispel
the least shadow of a doubt. A violent exhumation would have a great
advantage over the natural exit: it would place the population of the
burrows immediately under my eyes, before the departure of either
sex. In this way, nothing could escape from me and I was dispensed
from a watch which, for all its attentiveness, was not to be relied
upon absolutely. I therefore resolve upon a reconnaissance with the
I dig down to the full depth of the galleries and remove large lumps
of earth which I take in my hands and break very carefully so as to
examine all the parts that may contain cells. Halicti in the perfect
state predominate, most of them still lodged in their unbroken
chambers. Though they are not quite so numerous, there are also
plenty of pupae. I collect them of every shade of colour, from dead-
white, the sign of a recent transformation, to smoky-brown, the mark
of an approaching metamorphosis. Larvae, in small quantities,
complete the harvest. They are in the state of torpor that precedes
the appearance of the pupa.
I prepare boxes with a bed of fresh, sifted earth to receive the
larvae and the pupae, which I lodge each in a sort of half-cell
formed by the imprint of my finger. I will await the transformation
to decide to which sex they belong. As for the perfect insects, they
are inspected, counted and at once released.
In the very unlikely supposition that the distribution of the sexes
might vary in different parts of the colony, I make a second
excavation, at a few yards' distance from the other. It supplies me
with another collection both of perfect insects and of pupae and
When the metamorphosis of the laggards is completed, which does not
take many days, I proceed to take a general census. It gives me two
hundred and fifty Halicti. Well, in this number of Bees, collected in
the burrow before any have emerged, I perceive none, absolutely none
but females; or, to be mathematically accurate, I find just one male,
one alone; and he is so small and feeble that he dies without quite
succeeding in divesting himself of his nymphal bands. This solitary
male is certainly accidental. A female population of two hundred and
forty-nine Halicti implies other males than this abortion, or rather
implies none at all. I therefore eliminate him as an accident of no
value and conclude that, in the Cylindrical Halictus, the July
generation consists of females only.
The building-operations start again in the second week of July. The
galleries are restored and lengthened; new cells are fashioned and
the old ones repaired. Follow the provisioning, the laying of the
eggs, the closing of the cells; and, before July is over, there is
solitude again. Let me also say that, during the building-period, not
a male appears in sight, a fact which adds further proof to that
already supplied by my excavations.
With the high temperature of this time of the year, the development
of the larvae makes rapid progress: a month is sufficient for the
various stages of the metamorphosis. On the 24th of August there are
once more signs of life above the burrows of the Cylindrical
Halictus, but under very different conditions. For the first time,
both sexes are present. Males, so easily recognized by their black
livery and their slim abdomen adorned with a red ring, hover
backwards and forwards, almost level with the ground. They fuss about
from burrow to burrow. A few rare females come out for a moment and
then go in again.
I proceed to make an excavation with my spade; I gather
indiscriminately whatever I come across. Larvae are very scarce;
pupae abound, as do perfect insects. The list of my captures amounts
to eighty males and fifty-eight females. The males, therefore,
hitherto impossible to discover, either on the flowers around or in
the neighbourhood of the burrows, could be picked up to-day by the
hundred, if I wished. They outnumber the females by about four to
three; they are also further developed, in accordance with the
general rule, for most of the backward pupae give me only females.
Once the two sexes had appeared, I expected a third generation that
would spend the winter in the larval state and recommence in May the
annual cycle which I have just described. My anticipation proved to
be at fault. Throughout September, when the sun beats upon the
burrows, I see the males flitting in great numbers from one shaft to
the other. Sometimes a female appears, returning from the fields, but
with no pollen on her legs. She seeks her gallery, finds it, dives
down and disappears.
The males, as though indifferent to her arrival, offer her no
welcome, do not harass her with their amorous pursuits; they continue
to visit the doors of the burrows with a winding and oscillating
flight. For two months, I follow their evolutions. If they set foot
on earth, it is to descend forthwith into some gallery that suits
It is not uncommon to see several of them on the threshold of the
same burrow. Then each awaits his turn to enter; they are as
peaceable in their relations as the females who are joint owners of a
burrow. At other times, one wants to go in as a second is coming out.
This sudden encounter produces no strife. The one leaving the hole
withdraws a little to one side to make enough room for two; the other
slips past as best he can. These peaceful meetings are all the more
striking when we consider the usual rivalry between males of the same
No rubbish-mound stands at the mouth of the shafts, showing that the
building has not been resumed; at the most, a few crumbs of earth are
heaped outside. And by whom, pray? By the males and by them alone.
The lazy sex has bethought itself of working. It turns navvy and
shoots out grains of earth that would interfere with its continual
entrances and exits. For the first time I witness a custom which no
Hymenopteron had yet shown me: I see the males haunting the interior
of the burrows with an assiduity equalling that of the mothers
employed in nest-building.
The cause of these unwonted operations soon stands revealed. The
females seen flitting above the burrows are very rare; the majority
of the feminine population remain sequestered under ground, do not
perhaps come out once during the whole of the latter part of summer.
Those who do venture out go in again soon, empty-handed of course and
always without any amorous teasing from the males, a number of whom
are hovering above the burrows.
On the other hand, watch as carefully as I may, I do not discover a
single act of pairing out of doors. The weddings are clandestine,
therefore, and take place under ground. This explains the males'
fussy visits to the doors of the galleries during the hottest hours
of the day, their continual descents into the depths and their
continual reappearances. They are looking for the females cloistered
in the retirement of the cells.
A little spade-work soon turns suspicion into certainty. I unearth a
sufficient number of couples to prove to me that the sexes come
together underground. When the marriage is consummated, the red-
belted one quits the spot and goes to die outside the burrow, after
dragging from flower to flower the bit of life that remains to him.
The other shuts herself up in her cell, there to await the return of
the month of May.
September is spent by the Halictus solely in nuptial celebrations.
Whenever the sky is fine, I witness the evolutions of the males above
the burrows, with their continual entrances and exits; should the sun
be veiled, they take refuge down the passages. The more impatient,
half-hidden in the pit, show their little black heads outside, as
though peeping for the least break in the clouds that will allow them
to pay a brief visit to the flowers round about. They also spend the
night in the burrows. In the morning, I attend their levee; I see
them put their head to the window, take a look at the weather and
then go in again until the sun beats on the encampment.
The same mode of life is continued throughout October, but the males
become less numerous from day to day as the stormy season approaches
and fewer females remain to be wooed. By the time that the first
cold weather comes, in November, complete solitude reigns over the
burrows. I once more have recourse to the spade. I find none but
females in their cells. There is not one male left. All have
vanished, all are dead, the victims of their life of pleasure and of
the wind and rain. Thus ends the cycle of the year for the
In February, after a hard winter, when the snow had lain on the
ground for a fortnight, I wanted once more to look into the matter of
my Halicti. I was in bed with pneumonia and at the point of death, to
all appearances. I had little or no pain, thank God, but extreme
difficulty in living. With the little lucidity left to me, being able
to do no other sort of observing, I observed myself dying; I watched
with a certain interest the gradual falling to pieces of my poor
machinery. Were it not for the terror of leaving my family, who were
still young, I would gladly have departed. The after-life must have
so many higher and fairer truths to teach us.
My hour had not yet come. When the little lamps of thought began to
emerge, all flickering, from the dusk of unconsciousness, I wished to
take leave of the Hymenopteron, my fondest joy, and first of all of
my neighbour, the Halictus. My son Emile took the spade and went and
dug the frozen ground. Not a male was found, of course; but there
were plenty of females, numbed with the cold in their cells.
A few were brought for me to see. Their little chambers showed no
efflorescence of rime, with which all the surrounding earth was
coated. The waterproof varnish had been wonderfully efficacious. As
for the anchorites, roused from their torpor by the warmth of the
room, they began to wander about my bed, where I followed them
vaguely with my fading eyes.
May came, as eagerly awaited by the sick man as by the Halicti. I
left Orange for Serignan, my last stage, I expect. While I was
moving, the Bees resumed their building. I gave them a regretful
glance, for I had still much to learn in their company. I have never
since met with such a mighty colony.
These old observations on the habits of the Cylindrical Halictus may
now be followed by a general summary which will incorporate the
recent data supplied by the Zebra Halictus and the Early Halictus.
The females of the Cylindrical Halictus whom I unearth from November
onwards are evidently fecundated, as is proved by the assiduity of
the males during the preceding two months and most positively
confirmed by the couples discovered in the course of my excavations.
These females spend the winter in their cells, as do many of the
early-hatching melliferous insects, such as Anthophorae and Mason-
bees, who build their nests in the spring, the larvae reaching the
perfect state in the summer and yet remaining shut up in their cells
until the following May. But there is this great difference in the
case of the Cylindrical Halictus, that in the autumn the females
leave their cells for a time to receive the males under ground. The
couples pair and the males perish. Left alone, the females return to
their cells, where they spend the inclement season.
The Zebra Halicti, studied first at Orange and then, under better
conditions, at Serignan, in my own enclosure, have not these
subterranean customs: they celebrate their weddings amid the joys of
the light, the sun and the flowers. I see the first males appear in
the middle of September, on the centauries. Generally there are
several of them courting the same bride. Now one, then another, they
swoop upon her suddenly, clasp her, leave her, seize hold of her
again. Fierce brawls decide who shall possess her. One is accepted
and the others decamp. With a swift and angular flight, they go from
flower to flower, without alighting. They hover on the wing, looking
about them, more intent on pairing than on eating.
The Early Halictus did not supply me with any definite information,
partly through my own fault, partly through the difficulty of
excavation in a stony soil, which calls for the pick-axe rather than
the spade. I suspect her of having the nuptial customs of the
There is another difference, which causes certain variations of
detail in these customs. In the autumn, the females of the
Cylindrical Halictus leave their burrows seldom or not at all. Those
who do go out invariably come back after a brief halt upon the
flowers. All pass the winter in the natal cells. On the other hand,
those of the Zebra Halictus move their quarters, meet the males
outside and do not return to the burrows, which my autumn excavations
always find deserted. They hibernate in the first hiding-places that
In the spring, the females, fecundated since the autumn, come out:
the Cylindrical Halicti from their cells, the Zebra Halicti from
their various shelters, the Early Halicti apparently from their
chambers, like the first. They work at their nests in the absence of
any male, as do also the Social Wasps, whose whole brood has perished
excepting a few mothers also fecundated in the autumn. In both
cases, the assistance of the males is equally real, only it has
preceded the laying by about six months.
So far, there is nothing new in the life of the Halicti; but here is
where the unexpected appears: in July, another generation is
produced; and this time without males. The absence of masculine
assistance is no longer a mere semblance here, due to an earlier
fecundation: it is a reality established beyond a doubt by the
continuity of my observations and by my excavations during the summer
season, before the emergence of the new Bees. At this period, a
little before July, if my spade unearth the cells of any one of my
three Halicti, the result is always females, nothing but females,
with exceedingly rare exceptions.
True, it may be said that the second progeny is due to the mothers
who knew the males in autumn and who would be able to nidify twice a
year. The suggestion is not admissible. The Zebra Halictus confirms
what I say. She shows us the old mothers no longer leaving the home
but mounting guard at the entrance to the burrows. No harvesting- or
pottery-work is possible with these absorbing doorkeeping-functions.
Therefore there is no new family, even admitting that the mothers'
ovaries are not depleted.
I do not know if a similar argument is valid in the case of the
Cylindrical Halictus. Has she any general survivors? As my attention
had not yet been directed on this point in the old days, when I had
the insect at my door, I have no records to go upon. For all that, I
am inclined to think that the portress of the Zebra Halictus is
unknown here. The reason of this absence would be the number of
workers at the start.
In May, the Zebra Halictus, living by herself in her winter retreat,
founds her house alone. When her daughters succeed her, in July, she
is the only grandmother in the establishment and the post of portress
falls to her. With the Cylindrical Halictus, the conditions are
different. Here the May workers are many in the same burrow, where
they dwell in common during the winter. Supposing that they survive
when the business of the household is finished, to whom will the
office of overseer fall? Their number is so great and they are all so
full of zeal that disorder would be inevitable. But we can leave this
small matter unsettled pending further information.
The fact remains that females, females exclusively, have come out of
the eggs laid in May. They have descendants, of that there is no room
for doubt; they procreate though there are no males in their time.
>From this generation by a single sex, there spring, two months later,
males and females. These mate; and the same order of things
To sum up, judging by the three species that form the subject of my
investigations, the Halicti have two generations a year: one in the
spring, issuing from the mothers who have lived through the winter
after being fecundated in the autumn; the other in the summer, the
fruit of parthenogenesis, that is to say, of reproduction by the
powers of the mother alone. Of the union of the two sexes, females
alone are born; parthenogenesis gives birth at the same time to
females and males.
When the mother, the original genitrix, has been able once to
dispense with a coadjutor, why does she need one later? What is the
puny idler there for? He was unnecessary. Why does he become
necessary now? Shall we ever obtain a satisfactory answer to the
question? It is doubtful. However, without much hope of succeeding we
will one day consult the Gall-fly, who is better-versed than we in
the tangled problem of the sexes.