Classic Audiobook Collection - The Behavior of the Honey Bee in Pollen Collecting by D. B. Casteel ~ Full Audiobook [science]
Episode Date: November 14, 2022The Behavior of the Honey Bee in Pollen Collecting by D. B. Casteel audiobook. Genre: science In The Behavior of the Honey Bee in Pollen Collecting, D. B. Casteel offers a clear, observation-driven s...tudy of how worker honey bees locate, gather, and manage pollen - the protein-rich resource that fuels brood rearing and colony growth. Moving from the hive outward into the field, Casteel follows the forager's work step by step: how bees choose among blooming plants, how they loosen and pack pollen onto specialized body structures, and how the familiar pollen loads are formed and carried back to the colony. Along the way, the book examines the signals and practical constraints that shape pollen foraging, including floral traits, weather, time of day, and the needs of the brood nest, and it distinguishes pollen collecting from nectar foraging in both purpose and technique. Written to connect careful natural history with useful insight, the study highlights what these behaviors mean for beekeeping, crop pollination, and the broader relationship between insects and flowering plants. The result is a focused introduction to the mechanics and logic of pollen collection, inviting listeners to see a common backyard insect as a finely tuned biological system. For ad-free listening try our premium subscription Chapters (Approximate) (00:00:00) Chapter 01 (00:08:53) Chapter 02 (00:12:01) Chapter 03 (00:17:53) Chapter 04 (00:20:59) Chapter 05 (00:26:26) Chapter 06 (00:34:44) Chapter 07 (00:45:24) Chapter 08 (01:13:47) Chapter 09 (01:20:37) Chapter 10 Learn more about your ad choices. Visit megaphone.fm/adchoices
Transcript
Discussion (0)
The Behavior of the Honeybee in Pollen Collecting by D.B. Castile, Ph.D.
Section 1. Introduction and the structures concerned in the manipulation of pollen.
Introduction
While working upon the problem of wax scale manipulation during the summer of 1911,
the writer became convinced that the so-called wax shears or pinchers of the worker honey
have nothing whatever to do with the extraction of the wax scales from their pockets,
but rather that they are organs used in loading the pollen from the pollen combs of the hind legs
into the corbicula or pollen baskets.
Further observations made at that time disclosed the exact method by which the hind legs
are instrumental in the pollen loading process,
and also the way in which the middle legs and the hind legs in padded.
down the pollen masses. During the summer of 1912, additional information was secured,
more particularly that relating to the manner in which pollen is collected upon the body
and legs of the bee, how it is transferred to the hind legs, how it is moistened, and finally
the method by which it is stored in the hive for future use.
In the present paper a complete account will be given
of the history of the pollen from the time it leaves the flower until it rests within the cells
of the hive. The points of more particular interest in the description of pollen manipulation
refer to, one, the movements concerned in gathering the pollen from the flowers upon the body
and legs, two, the method by which the baskets of the hind legs receive the loads which they
carry to the hive, and three,
the manner in which the bee moisons pollen and renders it sufficiently cohesive for packing and transportation the structures concerned in the manipulation of pollen
the hairs which cover the body and appendages of the bee are of the utmost importance in the process of pollen gathering for the purpose of this account these hairs may be classified roughly as one branched hairs and branched hairs and
two unbranched hairs, the latter including both long, slender hairs, and stiff spine-like structures.
Of these two classes, the branched hairs of the more numerous. They make up the hairy coat of the
head, thorax, and abdomen, with the exception of short sensory spines, as those found upon the
antenna and perhaps elsewhere, and the stiff unbranched hairs which cover the surfaces of the
compound eyes. Branched hairs are also found upon the legs, more particularly upon the more
proximal segments. A typical branched hair is composed of a long, slender main axis, from which
sprang numerous short lateral barbs. Grains of pollen are caught and held in the
between the axis and the barbs and between the barbs of contiguous hairs.
The hairy covering of the body and legs thus serves as a collecting surface,
upon which pollen grains are temporarily retained,
and from which they are later removed by the combing action of the brushes of the legs.
Although, as above noted, some unbranched hairs are located upon the body of the bee,
they occur in greatest numbers upon the more distal segments of the appendages.
They are quite diverse in form,
some being extremely long and slender,
such as those which curve over the pollen baskets,
others being stout and stiff,
as those which form the collecting brushes and the pectin spines.
The mouth parts of the bee are also essential in the proper collection of pollen,
the mandibles are used to scrape over the anthers of flowers,
and considerable pollen adheres to them and is later removed.
The same is true of the maxilla and tongue.
From the mouth comes the fluid by which the pollen grains are moistened.
The legs of the worker bee are especially adapted for pollen gathering.
Each leg bears a collecting brush, composed of stiff, unbranched hairs.
set closely together. These brushes are located upon the first or most proximal
tarsal segment of the legs, known technically as the palma of the forelegs, and as the
planter of the middle and hind pair. The brush of the foreleg is elongated and of
slight width, that of the middle leg, broad and flat, while the brush upon the
planta of the hind leg is the broadest of all, and is also the most highly specialized.
In addition to these well-marked brushes, the distal ends of the tibia of the fore and middle
legs bear many stiff hairs, which function as pollen collectors, and the distal tarsal
joints of all legs bear similar structures. The tibia and the planta of the hind legs of the worker bee
are greatly flattened.
The outer surface of the tibia
is marked by an elongated depression,
deepest at its distal end,
and bounded laterally by elevated margins.
From the lateral boundaries of this depression
spring many long hairs,
some of which arch over the concave outer surface of the tibia,
and thus form a kind of receptacle or basket,
to which the name corbicula or pollen basket is given.
The lower or distal end of the tibia articulates at its anterior edge with the planta.
The remaining portion of this end of the tibia is flattened and slightly concave,
its surface sloping upward from the inner to the outer surface of the limb.
Along the inner edge of this surface runs a row of short,
stiff backwardly directed spines, from 15 to 21 in number, which form the pectin or comb of the
tibia. The lateral edge of this area forms the lower boundary of the corbicular depression,
and is marked by a row of very fine hairs which branch at their free ends. Immediately above these
hairs, springing from the floor of the corbiculi, are found seven or eight miles.
minute spines, and above them one long hair which reaches out over the edge of the basket.
The broad flat planta, metatarsus, or proximal tarsal segment of the hind leg,
is marked on its inner surface by several rows of stiff, distally directed spines, which form
the pollen combs.
About twelve of these transverse rows may be distinguished, although some of them are
are not complete. The most distal row, which projects beyond the edge of the
planter, is composed of very strong, stiff spines, which function in the removal of the
wax scales. The upper or proximal end of the planta is flattened and
projects in a posterior direction to form the oracle. The surface of the
oracle is marked with short, blunt spines, pirourens, pirourens,
middle in form, and a fringe of fine hairs with branching ends extends along its lateral edge.
This surface slopes upward and outward.
End of Section 1
Section 2 of The Behavior of the Honey Bee in Pollen Collecting.
This Librovoc's recording is in the public domain.
The Behavior of the Honeybee in Pollen Collecting by D.B. Castile.
Section 2. The pollen supply.
When bees collect pollen from flowers, they may be engaged in this occupation alone, or it may combine it with nectar gathering.
From some flowers the bees take only nectar, from others only pollen.
A third class of flowers furnishes an available supply of both of these substances,
but even where both pollen and nectar are obtainable,
a bee may gather nectar and disregard the pollen.
This is well illustrated by the case of white clover.
If bees are watched while working upon clover flowers,
the observer will soon perceive some which bear pollen masses upon their hind legs,
while others will continue to visit flower after flower,
dipping into the blossoms and securing a plentiful supply of nectar, yet entirely neglecting the pollen.
The supply of pollen which is available for the bees varies greatly among different flowers.
Some furnish an abundant amount and present it to the bee in such a way that little difficulty is experienced in quickly securing an ample load,
while others furnish but little.
When flowers are small, and when the bee approaches them from above,
little if any pollen is scattered over the bee's body,
all that it acquires being first collected upon the mouth and neighboring parts,
of very different conditions are met with when bees visit such plants as corn and ragweed.
The flowers of these plants are pendant and possess an abundant supply of pollen,
which falls in showers over the bodies of the bees as they crawl beneath the blossoms.
The supply of pollen which lodges upon the body of the bee will thus differ considerably in amount,
depending upon the type of flower from which the bee is collecting,
and the same is true regarding the location upon the body of a bee of pollen grains
which are available for storage in the baskets.
Moreover, the movements concerned in the collection of the pollen from the various body parts of the bee upon which it lodges
will differ somewhat in the two cases, since a widely scattered supply requires for its collection
additional movements, somewhat similar in nature to those which the bee employs in cleaning the hairs
which cover its body.
End of Section 2.
Section 3 of the behavior of the honey bee in pollen collecting.
This Librevox recording is in the public domain.
The Behavior of the Honeybee in Pollen Collecting by D.B. Castile.
Section 3. General statement of the pollen collecting process.
A very complete knowledge of the pollen gathering behavior of the worker honey bee
may be obtained by a study of the actions of bees
which are working upon a plant which yields pollen in abundance.
Sweet corn is an ideal plant for this purpose,
and it will be used as a basis for the description which follows.
In attempting to outline the method by which pollen is manipulated,
the writer wishes it to be understood
that he is recounting that which he has seen
and that the description is not necessarily complete,
although he is of the opinion that it is very nearly so.
The movements of the legs and of the mouth parts
are so rapid and so many members are in action at once
that it is impossible for the eye to follow all at the same time.
However, long-continued observation,
assisted by the study of instantaneous photographs,
gives confidence that the statements record,
ordered are accurate, although some movements may have escaped notice.
To obtain pollen from corn, the bee must find a tassel in the right stage of ripeness,
with flowers open and stamens hanging from them.
The bee alights upon a spike and crawls along it, clinging to the pendant anthers.
It crawls over the anthers, going from one flower to another along the spike,
being all the while busily engaged in the task of obtaining pollen.
This reaches its body in several ways.
As the bee moves over the anthers,
it uses its mandibles and tongue,
biting the anthers and licking them
and securing a considerable amount of pollen upon these parts.
This pollen becomes moist and sticky,
since it is mingled with fluid from the mouth.
A considerable amount of pollen is dislodged from the anthers as the bee moves over them.
All of the legs receive a supply of this free pollen, and much adheres to the hairs which cover the body,
more particularly to those upon the ventral surface.
This free pollen is dry and powdery, and is very different in appearance from the moist pollen masses,
with which the bee returns to the hive.
Before the return journey,
this pollen must be transferred to the baskets
and securely packed in them.
After the bee has traversed a few flowers along the spike
and has become well supplied with free pollen,
it begins to collect it from its body, head, and forward appendages
and to transfer it to the posterior pair of legs.
This may be accomplished while the bee is resting upon the flower
or while it is hovering in the air before seeking additional pollen.
It is probably more thoroughly and rapidly accomplished
while the bee is in the air,
since all of the legs are then free to function in the gathering process.
If the collecting bee is seized with foreseps
and examined after it has crawled over the stamens of a few flowers of the corn,
its legs and the ventral surface of its body are found to be thickly powdered over with pollen if the bee hovers in the air for a few moments and is then examined
very little pollen is found upon the body or upon the legs except the masses within the pollen baskets while in the air it has accomplished the work of collecting some of the scattered grains and of storing them in the baskets while others have been brought
from the body. In attempting to describe the movements by which this result is accomplished,
it will be best first to sketch briefly the rolls of the three pairs of legs.
They are as follows. A. The first pair of legs remove scattered pollen from the head and the
region of the neck, and the pollen that has been moistened by fluid substances from the mouth.
B. The second pair of legs,
legs remove scattered pollen from the thorax, more particularly from the ventral region,
and they receive the pollen that has been collected by the first pair of legs.
C. The third pair of legs collect a little of the scattered pollen from the abdomen,
and they receive pollen that has been collected by the second pair.
Nearly all of this pollen is collected by the pollen combs of the hind legs,
and is transferred from the combs to the pollen baskets, or corbiculi, in a manner to be described later.
It will thus be seen that the manipulation of pollen is a successive process,
and that most of the pollen at least passes backward from the point where it happens to touch the bee,
until it finally reaches the corbiculi or is accidentally dislodged and falls from the rapidly moving limbs.
End of Section 3.
Section 4 of The Behavior of the Honeybee in Pollen Collecting.
This Librevox recording is in the public domain.
The Behavior of the Honeybee in Pollen Collecting by D.B. Castile.
Section 4.
Action of the four legs and mouth parts.
Although the pollen of some plants appears to be somewhat sticky,
it may be stated that as a general rule, pollen cannot be successfully manipulated and packed in the baskets
without the addition of some fluid substance, preferably a fluid which will cause the grains to cohere.
This fluid, the nature of which will be considered later, comes from the mouth of the bee,
and is added to the pollen which is collected by the mouth parts,
and to that which is brought into contact with the protruding tongue and maxilla,
and, as will appear, this fluid also becomes more generally distributed upon the legs
and upon the ventral surface of the collecting bee.
When a bee is collecting from the flowers of corn,
the mandibles are actively engaged in seizing, biting,
and scraping the anthers as the bee crawls over the pendant stamens.
usually but not always the tongue is protruded and wipes over the stamens collecting pollen and moistening the grains thus secured
some of the pollen may possibly be taken into the mouth all of the pollen which comes in contact with the mouth parts is thoroughly moistened receiving more fluid than is necessary for rendering the grains cohesive
this exceedingly wet pollen is removed from the mouth parts by the fore legs and probably the middle legs also secure a little of it directly since they sometimes brush over the lower surface of the face and the mouth
in addition to removing the very moist pollen from the mouth the four legs also execute cleansing movements over the sides of the head and neck and the anterior region of the thoraxe
thereby collecting upon their brushes, a considerable amount of pollen which has fallen directly upon these regions,
and this is added to the pollen moistened from the mouth, thereby becoming moist by contact.
The brushes of the forelegs also come in contact with the anterior breast region,
and the hairs which cover this area become moist with the sticky exudation,
which the forelegs have acquired in the process of wiping pollen from the tongue, maxilla, and mandibles.
End of Section 4
Section 5 of the behavior of the honeybee in pollen collecting.
This Librevox recording is in the public domain.
The behavior of the honeybee in pollen collecting by D.B. Castile.
Section 5. Action of the Middle
legs. The middle legs are used to collect the pollen gathered by the four legs and mouth
parts to remove free pollen from the thoracic region and to transport their load of pollen to the
hind legs, placing most of it upon the pollen combs of these legs, although a slight amount is
directly added to the pollen masses in the corbiculi. Most of the pollen of the middle legs is
gathered upon the conspicuous brushes of the first tarsal segments or plenty of these legs.
In taking pollen from a foreleg, the middle leg of the same side is extended in a forward direction
and is either grasped by the flexed foreleg or rubbed over the foreleg as it is bent downward and
backward. In the former movement, the foreleg flexes sharply upon itself until the tarsal brush and
coxas nearly meet. The collecting brush of the middle leg is now thrust in between the tarsis and coxa
of the foreleg and wipes off some of the pollen from the foreleg brush. The middle leg brush is then
raised and combs down over the flexed foreleg, thus removing additional pollen from the outer
surface of this leg. The middle leg also, at times, reaches far forward, stroking down, and
over the foreleg before it is entirely flexed and apparently combing over with its
tarsal brush the face and mouth parts themselves when the middle leg reaches forward to
execute any of the above movements the direction of the stroke is outward forward
and then back toward the body the action ending with the brush of the leg in
contact with the long hairs of the breast and with those which spring from the
proximal segments of the forelegs, coxia, trocanter, femur.
As a result of the oft-repeated contact of the brushes of the middle and forelegs with the
breast, the long, branched hairs which cover this region, become quite moist and sticky,
since the brushes of these two pairs of legs are wet, and the pollen which they bear
possesses a superabundance of the moistening fluid.
Any dry pollen which passes over this region and touches these hairs receives moisture by contact with them.
This is particularly true of the free dry pollen, which the middle pair of legs collect by combing over the sides of the thorax.
The pollen upon the middle legs is transferred to the hind legs in at least two ways.
By far, the larger amount is deposited upon the pollen combs,
which lie on the inner surfaces of the planty of the hind legs.
To accomplish this, a middle leg is placed between the plenty of the two hind legs,
which are brought together so as to grasp the brush of the middle leg,
pressing it closely between them,
but allowing it to be drawn toward the body between the pollen combs of the two hind legs.
This action results in the transference of the pollen from the middle leg brush
to the pollen combs of the hind leg of the opposite side,
since the combs of that leg scrape over the pollen-laden brush of the middle leg.
This action may take place while the bee is on the wing
or before it leaves the flower.
The middle legs place a relatively small amount of pollen
directly upon the pollen masses in the corbiculi.
This is accomplished when the brushes of the middle legs
are used to pat down the pollen mass,
and to render them more compact.
The legs are used for this purpose quite often during the process of loading the baskets,
and a small amount of pollen is incidentally added to the masses
when the brushes come into contact with them.
A misinterpretation of this action has led some observers into the erroneous belief
that all or nearly all of the corbicular pollen is scraped from the middle-leg brushes by the hairs,
which fringe the sides of the baskets.
The middle legs do not scrape across the baskets,
but merely pat downward upon the pollen which is there accumulating.
It is also possible that in transferring pollen from the middle leg of one side
to the plant of the opposite hind leg,
the middle leg brush may touch and rub over the pectin of the hind leg
and thus directly place some of its pollen behind the pectin spines.
Such a result is, however, very doubtful.
End of Section 5.
Section 6 of The Behavior of the Honeybee in Pollen Collecting.
This Librevox recording is in the public domain.
The Behavior of the Honeybee in Pollen Collecting by D.B. Castile.
Section 6.
Action of the hind legs
The middle legs contribute the major portion of the pollen which reaches the hind legs,
and all of it in cases where all of the pollen first reaches the bee in the region of the mouth.
However, when much pollen falls upon the body of the bee,
the hind legs collect a little of it directly, for it falls upon their brushes
and is collected upon them when these legs execute cleansing movements
to remove it from the ventral surface and sides of the abdomen.
All of the pollen which reaches the corbiculi,
with the exception of the small amount placed there by the middle legs
when they pat down the pollen masses,
passes first to the pollen combs of the plantee.
When in the act of loading pollen from the planter brushes to the corbiculi,
The two hind legs hang beneath the abdomen with the tibium femoral joints well drawn up toward the body.
The two planty lie close together with their inner surfaces nearly parallel to each other,
but not quite, since they diverge slightly at their distal ends.
The pollen combs of one leg are in contact with the pectin comb of the opposite leg.
If pollen is to be transferred from the right planta,
to the left basket, the right planter is drawn upward in such a manner that the pollen
combs of the right leg scrape over the pectin spines of the left. By this action, some of the pollen
is removed from the right planter combs and is caught upon the outer surfaces of the pectin
spines of the left leg. This pollen now lies against the pectin and upon the flattened distal
end of the left tibia. At this moment the planta of the left leg is flexed slightly, thus elevating
the oracle, and bringing the auricular surface into contact with the pollen which the pectin has
just received. By this action, the pollen is squeezed between the end of the tibia and the
surface of the oracle, and is forced upward against the distal end of the tibia, and on outward into
contact with the pollen mass accumulating in the corbicula. As this act, by which the left basket
receives a small contribution of pollen, is being completed, the right leg is lowered,
and the pectin of this leg is brought into contact with the pollen combs of the left
planter, over which they scrape as the left leg is raised, thus depositing pollen upon the
lateral surfaces of the pectin spines of the right leg. Right and left baskets thus receive
alternately successive contributions of pollen from the plant of the opposite leg. These loading movements
are executed with great rapidity, the legs rising and falling with a pump-like motion. A very small
amount of pollen is loaded at each stroke, and many strokes are required to load the baskets completely.
if one attempts to obtain from the literature of apiculture and zoology a knowledge of the method by which the pollen baskets themselves are loaded he is immediately confused by the diversity of the accounts available
The average textbook of zoology follows closely Cheshire's, in 1886,
description in which he says that,
The legs are crossed, and the metatarsus naturally scrapes its comb face
on the upper edge of the opposite tibia in the direction from the base of the combs toward their tips.
These upper hairs are nearly straight and pass between the comb teeth.
The pollen, as removed, is caught by the bent over hairs and secured.
Each scrape adds to the mass until the face of the joint is more than covered,
and the hairs just embrace the pellet.
Franz, in 1906, states that, translated,
the final loading of the baskets is accomplished by the crossing over of the hind-tarsal segments,
which rub and press upon each other.
Many other observers and textbook writers
evidently believed that the hind legs were crossed
in the loading process.
On the other hand, it is believed by some
that the middle legs are directly instrumental
in filling the baskets.
This method is indicated in the following quotation
from Fleischman and Xander in 1910, translated.
The second pair of legs transfer the pollen to the hind legs, where it is heaped up in the pollen masses.
The tibia of each hind leg is depressed on its outer side,
and upon the edges of this depression stand two rows of stiff hairs which are bent over the groove.
The brushes of the middle pair of legs rub over these hairs, liberating the pollen, which drops into the baskets.
a suggestion of the true method is given by homel in nineteen o six though his statements are somewhat indefinite after describing the method by which pollen is collected moistened and passed to the middle legs he states that translated
the middle legs place their loads upon the pollen combs of the hind legs there the sticky pollen is needed and is pushed across the pincher
is broken up into little masses and accumulates within the corbicula.
In accomplishing this, the legs cross,
and it is the tarsis of the right leg which pushes the pollen across the pincher of the left
and reciprocally.
The middle legs never functioned directly in loading the baskets,
though from time to time their sensitive extremities touch the accumulated mass
for the sake of giving assurance of its position and size.
The recent valuable papers of Sladen in 1911 and 1912,
who was the first to present a true explanation of the function of the abdominal scent gland of the bee,
give accounts of the process by which the pollen baskets are charged,
which are in close accord with the writer's ideas on this subject.
It is a pleasure to be able to confirm most of Slayden's observations and conclusions,
and weight is added to the probable correctness of the two descriptions
and interpretations of this process by the fact that the writer's studies and the conclusion
based upon them were made prior to the appearance of Sladen's papers and quite independent of them.
His description of the basket-loading process itself is so significant,
to the writer's own that a complete quotation from him is unnecessary.
A few differences of opinion will, however, be noted while discussing some of the movements
which the process involves.
As will later be noted, our ideas regarding the question of pollen moistening, collecting,
and transference are somewhat different.
End of Section 6
Section 7 of the behavior of the honey bee in pollen collecting
This Libravox recording is in the public domain
The Behavior of the Honey Bee in Pollen Collecting by D.B. Castile
Section 7
Additional details of the basket loading process
The point at which pollen enters the basket can best be determined
by examining the corbiculi of a bee
shortly after it has reached a flower, and before much pollen has been collected.
Within each pollen basket of such a bee is found a small mass of pollen,
which lies along the lower or distal margin of the basket.
It is in this position, because it has been scraped from the planter of the opposite leg by the pectin comb,
and has been pushed upward past the entrance of the basket by the continued addition of more from below,
propelled by the successive strokes of the oracle closer examination of the region between the pectin and the floor of the basket itself shows more pollen which is on its way to join that already squeezed into the basket
if the collecting bee is watched for a few moments the increase will readily be noted and the fact will be established that the accumulating mass is gradually working upward or proximally from the last
lower or distal edge of the corbicula, and is slowly covering the floor of this receptacle.
In many instances, the successive contributions remain for a time fairly separate,
the whole mass being marked by furrows transverse to the long axis of the tibia.
Sladen notes the interesting fact that in those rather exceptional cases when a bee gathers pollen
from more than one species of flowers,
the resulting mass within the corbicula
will show a stratification parallel to the distal end,
a condition which could result only from the method of loading here indicated.
As the pollen within the basket increases in amount,
it bulges outward and projects downward
below the lower edge of the basket.
It is held in position by the long hairs
which fringe the lateral sides of the basket,
and its shape is largely determined by the form of these hairs
and the direction in which they extend.
When the basket is fully loaded,
the mass of pollen extends laterally on both sides of the tibia,
but projects much farther on the posterior side,
for on this side the bounding row of hairs extends outward,
while on the anterior edge the hairs are more concerned,
curved, folding upward and over the basket. As the mass increases in thickness by additions
from below, it is held in position by these long hairs which edge the basket. They are pushed
outward, and many of them become partly embedded in the pollen as it is pushed up from below.
When the pollen grains are small and the whole mass is well moistened, the marks made by some of the
hairs will be seen on the sides of the load. These scratches are also transverse in direction,
and they show that the mass has been increased by additions of pollen pushed up from below.
Even a superficial examination of a heavily laden basket shows the fallacy of the supposition
that the long lateral fringing hairs are used to comb out the pollen from the brushes of either
the hind or middle legs by the crossing of these legs over the lateral edges of the baskets.
They are far from sufficiently stiff to serve this purpose, and their position with
relation to the completed load shows conclusively that they could not be used in the final
stages of the loading process, for the pollen mass has completely covered many of them,
and its outer surface extends far beyond their ends. They serve merely
to hold the pollen in place
and to allow the load to
project beyond the margins of the
tibia. The
oracle plays a very essential
part in the process of loading the
basket. This structure
comprises the whole of the
flattened proximal surface of the
planter, except the joint
of articulation itself,
and it extends outward in a
posterior direction a little
beyond the remaining planter edge.
The surface of
of the oracle is covered over with many blunt, short spines,
and its lateral margin is bounded by a row of short, rather pliable hairs, branched at their ends.
When the plant is flexed, the oracle is raised,
and its surface approaches the distal end of the tibia,
its inner edge, slipping up along the pectin spines,
and its outer hairy edge projecting into the opening which leads to the pollen bass
basket. With each upward stroke of the oracle, small masses of pollen which have been scraped
from the planter combs by the pectin are caught and compressed between the spiny surface of the
oracle and the surface of the tibia above it. The pressure thus exerted forces the pasty pollen
outward and upward, since it cannot escape past the base of the pectin and directs it into the
entrance of the corbicula. The outward and upward slant of the auricular surface and the projecting hairs
with which the outer edge of the oracle is supplied also aid in directing the pollen toward the basket.
Sladen states that in this movement the weak wing of the oracle is forced backward and thus allows
the escape of pollen toward the basket entrance, but this appears both doubtful and unnecessary,
since the angle of inclination of the oracle surface gives the pollen a natural outlet in the proper direction if the corbicula already contains a considerable amount of pollen
the contributions which are added to it at each stroke of the oracle come in contact with that already deposited and form a part of this mass which increases in amount by continued additions from below
if however the corbicula is empty and the process of loading is just beginning the first small bits of pollen which enter the basket must be retained upon the floor of the chamber until a sufficient amount has accumulated
to allow the long over-curving hairs to offer it effective support the sticky consistency of the pollen renders it likely to retain contact with the basket and certain structures near the entrance give additional support
several small sharp spines seven or eight in number spring from the floor of the basket immediately within the entrance and the entire lower edge of the corbicula is fringed with very small hairs which are branched at their ends
one large hair also springs from the floor of the basket somewhat back from the entrance which may aid in holding the pollen but it cannot function in this manner until a considerable
amount has been collected. As the pollen mass increases in size and hangs downward and backward over
the pectin and oracle, it shows upon its inner and lower surface a deep groove which runs
outward from the entrance to the basket. This groove results from the continued impact of the
outer end of the oracle upon the pollen mass. At each upward stroke of the oracle, its outward
comes in contact with the stored pollen as soon as the mass begins to bulge backward from the basket.
Although the process is a rather delicate one, it is entirely possible so to manipulate the hind legs
of a recently killed bee that the corbiculi of the two legs receive loads of pollen in a manner
similar to that above described. To accomplish this successfully, the operator must keep
the combs of the planty well supplied with moistened pollen. If the foot of first one leg and then the other
is grasped with forceps and so guided that the pollen combs of one leg rasp over the pectin spines of
the other, the pollen from the combs will be transferred to the corbiculi. To continue the loading
process in a proper manner, it is also necessary to flex the planter of each leg, just
after the pollen combs of the opposite leg have deposited pollen behind the pectin.
By this action the oracle is raised, compressing the pollen which the pectin has secured,
and forcing some upward into the corbicula.
Bees' legs, which have been loaded in this artificial manner, show pollen masses in their
corbiculi, which are entirely similar in appearance to those formed by the labors of the living
B. Moreover, by the above method of manipulation, the pollen appears first at the bottom of the
basket, along its lower margin, gradually extends upward along the floor of the chamber,
comes in contact with the overhanging hairs, and is shaped by them in a natural manner.
All attempts to load the basket by other movements, such as crossing the hind legs,
and scraping the planter combs over the lateral edges of the baskets give results which are entirely different from those achieved by the living bee.
End of Section 7
Section 8 of the behavior of the honey bee in pollen collecting.
This Libravox recording is in the public domain.
The Behavior of the Honeybee in Pollen Collecting by D.B. Castile.
Section 8.
Pollen moistening.
many descriptions have been written by others of the method by which pollen is gathered and moistened some of these are indefinite some are incorrect
while others are in part at least similar to my own interpretation of this process a few citations will here be given the bee first strokes the head in the proboscis with the brushes of the forelegs and moistenes these brushes with a little honey from the proboscis
so that with later strokes all of the pollen from the head is collected upon these brushes.
Then the middle-leg brushes remove this honey-moistened pollen from the fore-legs,
and they also collect pollen from the breast and the sides of the thorax.
Translation from Aylfield, 1861.
In his account of the basket-loading process,
Ailfield assigns to the middle-leg brushes the function of assemblies,
all of the pollen, even that from the planter combs, and of placing it on the corbiculi,
this latter act being accomplished by combing over the hairy edge of each basket with the middle
leg brush of the same side. It appears probable that the bee removes the pollen from the head,
breast, and abdomen by means of the hairy brushes, which are located upon the medial sides of
the tarsal segments of all of the legs, being most pronounced,
upon the hind legs. The pollen is thus brought together and is carried forward to the mouth,
where it is moistened with saliva and a little honey. Translation from Franz 1906.
Franz then says that this moistened pollen is passed backward and loaded. Since the pollen of many
plants is sticky and moist, it adheres to the surface of the basket. Dry pollen is moistened by
saliva so that it also sticks. Translation from Fleischman and Xander, 1910.
Pollen is taken from flowers principally by means of the tongue, but at times also by the mandibles,
by the forelegs, and middle legs. The brushes of the hind legs also load themselves,
collecting from the hairs of the body. The pollen dust thus gathered is always transmitted to the
mouth, where it is mixed with saliva. Translation from Hamel, 1906. Sladen considers the question of how
pollen is moistened by the honeybee, humble bee, and some other bees, but does not appear to reach
definite conclusions. In one of his papers, in 1912, he states that the pollen of some plants may be
found in the mouth cavity and in the region of the mouth, but he reaches the conclusion that
this pollen is comparatively dry, using the word in a relative sense. He asserts that,
nowhere but on the corbicula and the hind metatarsal brushes did I find the sticky pollen,
except sometimes on the tips of the long, branched hairs on the back or upper edges of the
tibii and femur of the middle legs, and then only in heavily laden bees, where it is reasonable
to suppose it had collected accidentally as the result of contact with the hind metatarsal
brushes. These and other considerations lead Sladen to think that, in the case of the bumblebee,
at least, the pollen may be moistened on the hind metatarsus with the tongue. He states that
the tongue of the bumblebee is of sufficient length to reach the hind metatarsus, or
planta, and that it might rub over the brushes of the metatarsai or be caught between them
when they are approximated, and thus moisten the two brushes simultaneously.
However, he has never seen the tongue of the collecting honey bee brought near to the hind legs,
and it appears probable to him that it cannot easily reach them.
possibly the middle or front legs are used as agents for conveying the honey in the case of the honey bee in the humble bee the tongue is longer and it could more easily moisten the hind legs in the way suggested
in an earlier paper slayden in nineteen twelve gives the following as his opinion of the way in which pollen dust is moistened with nectar although he states that this is one of the points which still remains a point which still remains a point which still remains a point
The only satisfactory manner in which, it seems to me, this can be done, is for the tongue to lick the tarsai or metatarsai of the forelegs, which are covered with stiff bristles, well suited for holding the nectar, the nectar, being then transferred to the metatarsal brushes on the middle legs, and from these again to the metatarsal brushes on the hind legs.
The latter being thus rendered sticky, the pollen dust would cling to them.
The different pairs of legs were certainly brought together occasionally, but not after every
scrape of the hind metatarsai, and their movements were so quick that it was impossible to see
what was done.
Still, several pollen-collecting bees that I killed had the tarsai and metatarsai of the
four legs, and the metatarsal brushes of the middle and hind legs, moistened with nectar,
and I think it probable that the moistening process, as outlined, is performed as a rule during
the flight from flower to flower. Sladen, in 1912, also considers the possibility that the fluid
which moistens the pollen might be secreted through the comb at the end of the tibia,
through the tibial tarsal joint, or from the surface of the oracle,
but finds no evidence of glandular openings in these regions.
A suggestion of a similar nature, apparently unknown to Sladen,
was made by Wolfe in 1873, who describes sweat glands,
which he claims are located within the hind tibia and the planta,
and which porous secretion upon the surface of the corbicula
and upon the upper end of the planter,
through many minute openings
located at the bases of hairs,
particularly those which arise
from the lateral margins of the corbicula.
Wolf is convinced that the fluid thus secreted
is the essential cohesive material
by which the grains of pollen are bound together
to form the solid mass
which fills each fully loaded basket.
He noticed that the mouth parts are used to collect
pollen and that some of it is moistened with honey or nectar, but he does not consider that the fluid
thus supplied is sufficient to explain adequately the facility with which the collecting bee
brings together the scattered grains of pollen and packs them away securely in the baskets.
Wolfe's description of the basket-loading process itself is strikingly similar to that advocated
later by Cheshire.
The writer is not prepared to deny the possibility
that the surface of the chitin of the hind legs of worker bees
may be moistened by the secretion of glands which lie beneath it,
but he is convinced that any fluid thus secreted
bears little or no relation to the cohesion of the pollen grains within the baskets.
Sections and dissected preparations of the hind legs of worker bees
show certain large cells which lie within the cavity of the leg
and which may function as secreting gland cells.
But similar structures occur in even greater numbers
within the hind legs of the drone,
and they are found within the hind legs of the queen.
As has been noted,
the extreme moisture of the planter combs
and of the tibiotarsal articulation of the hind leg
is readily understood when one reason
recalls the manner in which moist pollen is compressed between the oracle and the tibial surface above it from the account already given it is evident that in the opinion of the writer the mouth is the source from which the pollen moistening fluid is obtained
it is extremely difficult to determine with absolute accuracy the essential steps involved in the process of adding moisture to the pollen
in an endeavor to solve this problem the observer must of necessity consider a number of factors among which may be noted one the location upon the body of the collecting bee of moist and of comparatively dry pollen
two the movements concerned in the pollen gathering and pollen transferring processes three the relative moisture of those parts which handle
pollen, four, the chemical differences between the natural pollen of the flower and that of
the corbiculi and of the cells of the hive, and five, the observer must endeavor to distinguish
between essential phenomena and those which are merely incidental or accidental.
In the first place, it should be noted that the relative dampness of pollen within the corbiculi
depends very largely upon the character of the flower from which the pollen grains are gathered.
When little pollen is obtained, it is much more thoroughly moistened,
and this is particularly true in cases when the pollen is all, or nearly all,
collected in the region of the mouth, the forelegs, and head.
When a bee takes pollen from white or sweet clover,
practically all of it first touches the bee in the field,
regions. It immediately becomes moist and in this condition is passed
backward until it rests within the baskets. There is no question of dry and
wet pollen or of collecting movements to secure dry pollen from other regions of
the body or of the ultimate method by which such free dry pollen becomes
moist. The sticky fluid which causes pollen grains to
to cohere, is found upon all of the legs in the region of their brushes, although the pollen
combs and oracles of the hind legs are likely to show it in greatest abundance.
Since nearly all of the pollen within each basket has passed over the oracle, has been pressed
upward and squeezed between the oracle and the end of the tibia and the pollen mass above,
and by this compression has lost some of its fluid, which runs
down over the oracle and onto the combs of a planter.
It is not necessary to invoke any special method by which these areas receive their
moisture. The compressing action of the oracle squeezing heavily moistened pollen upward
into the basket is entirely sufficient to account for the abundance of sticky fluid
found in the neighborhood of each hind tibiotarsal joint. As has been noted, the brush
of the forelegs acquire moisture directly by stroking over the proboscis and by handling extremely moist pollen taken from the mouth parts.
The middle leg brushes become moist by contact with the foreleg and hind leg brushes,
probably also by touching the mouth parts themselves and bypassing moist pollen backward.
The hairy surface of the breast is moistened by contact with the fore and the mid-and-minger.
of four and mid-leg brushes, and with the moist pollen which they bear.
The problem of the method of pollen moistening is somewhat more complicated in the case of flowers
which furnish an excessive supply. Under such conditions, the entire ventral surface of the
collecting bee becomes liberally sprinkled with pollen grains, which either will be removed
and dropped, or will be combed from the bristles and branching
here's, needed into masses, transferred, and loaded.
The question naturally arises whether the movements here are the same as when the plant yields,
but a small amount of pollen which is collected by the mouth parts and anterior legs.
In the opinion of the rider, they are essentially the same, except for the addition of cleansing
movements, executed chiefly by the middle and hind legs, for the collection of pollen which has fallen
upon the thorax, upon the abdomen, and upon the legs themselves. Indeed, it is questionable
as to just how much of this plentiful supply of free pollen is really used in forming the corbicular
masses. Without doubt, much of it falls from the bee and is lost, and in cases where, we are
it is extremely abundant and the grains are very small in size, an appreciable amount still
remains entangled among the body hairs when the bee returns to the hive.
Yet it is also evident that some of the dry pollen is mingled with the moistened material
which the mouth parts and forelegs acquire, and together with this is transferred to the baskets.
In all cases, the pollen gathering process starts with the moist pollen from the mouth region.
This pollen is passed backward, and in its passage it imparts additional moisture to those
body regions which it touches, the brushes of the fore and middle legs, the planty of the
hind legs, and the hairs of the breast which are scraped over by the four and middle
leg brushes. This moist pollen, in its passage backward, may also pick up and add to itself
grains of dry pollen with which it accidentally comes in contact. Some of the free dry pollen which
falls upon the moist brushes or upon the wet hairs of the thorax is also dampened. Some of the
dry pollen which is cleaned from the body by the action of all the legs, meets with the wet
brushes or with the little masses of wet pollen, and itself becomes wet by contact.
Pollen grains which reach the corbiculi, either dry or but slightly moistened, are soon rendered
moist by contact with those already deposited. Little pollen gets by the sticky surfaces of
combs of the planter or past the oracles without becoming thoroughly moist.
Sladen very aptly compares the mixture of dry pollen with the wet to the kneading of wet dough with
dry flour and suggests that the addition of dry pollen may be of considerable advantage,
since otherwise the brushes, particularly those of the hind legs, would become sticky,
just as the board and rolling pin gets sticky in working up a ball of dough if one does not add flour.
The addition of a considerable amount of dry pollen gives exactly this result,
for the carbiculi then rapidly become loaded with pollen mixed with a minimum supply of moisture,
and the brushes remain much drier than would otherwise be the case.
However, if too much dry pollen is added, the resulting loads which the bees carry back to the hives are likely to be irregular,
for the projecting edges of the masses may crumble through lack of a sufficient amount of the cohesive material by which the grains are bound together.
On the other hand, it does not appear at all necessary to mix much dry pollen with the wet,
nor do the brushes become sufficiently sticky from the presence of an abundance of the
moistening fluid to endanger their normal functional activity.
I have observed bees bringing in pollen masses which were fairly liquid with moisture,
and the pollen combs were also covered with fluid,
yet the baskets were fully and symmetrically loaded.
Sladen's different interpretations of the pollen moistening process,
are rather confusing, and it is difficult to distinguish between what he states as observed facts
and what he puts forward as likely hypotheses.
He agrees with me in his observation that all of the legs become moist in the region of their brushes,
and also in his supposition that this moisture is transferred to them from the mouth.
In this moistening process, my mind.
observations show that the fluid concerned is passed backward by the contact of the middle-leg
brushes with the fore-leg brushes and that the middle-leg brushes in turn convey moisture to the
planty as they rub upon them. I am also convinced that the wet pollen grains furnish additional
moisture to the brushes as they pass backward, and this is particularly true in the case of
the extremely moist surfaces of the oracle
and the pollen combs of the planter,
since here moisture is pressed from the pollen upon these areas.
The pollen upon the fore and middle leg brushes
is not always dry, even in a relative sense.
In describing pollen manipulation,
several writers state that dry pollen is picked up
by the brushes of the legs
and is carried forward to the mouth.
There moistened, according to some masticated,
and is then carried backward by the middle legs for loading.
Obviously, such accounts do not apply to cases
in which all of the pollen is collected by mouth parts and four legs.
Do they apply in cases where much pollen falls on the body and limbs?
Without doubt, a certain amount of this free pollen is brought forward
when the middle legs, bearing some of it, sweep forward and downward
over the forelegs, mouth parts, and breast.
However, it does not appear to the rider
that this dry pollen is carried to the mouth
for the specific purpose of moistening it,
or that it is essential to its moistening
that it be brought in contact with the mouth.
Some of it touches the moist hairs of the forelegs and breast
and is moistened by contact.
All that remains on the brushes of the middle
legs secures moisture from these brushes or from wet pollen which the brushes collect from the mouth
parts or forelegs. The supposed necessity of carrying forward pollen to the mouth for
moistening is a delusion. Some is accidentally brought forward and into contact with the mouth
and gets wet, but the process is not essential. If the pollen which bees transports,
to their hives has been moistened with some fluid substance, which causes the grains to
cohere, this addition should be indicated by differences in the results of an analysis of pollen
from a plant as compared with that found in the corbiculi of a bee which has been working
on this plant. For the sake of determining this difference, and in an endeavor to ascertain,
if possible, the approximate nature of the added fluid,
analyses were made of three kinds of pollen as follows.
One, pollen collected by hand from the corn plant itself.
Two, pollen taken from the corbiculi of bees which had secured their supply from corn.
Three, pollen stored in the cells of the hive.
In the first two cases, pollen.
from the same species of plant, corn, was used.
The material from the cells of the hive was composed largely of corn pollen,
but contained an admixture of some other pollens.
The writer is indebted to Dr. D.P. Dunbar of the Bureau of Chemistry
for the following analysis.
Pollin direct from corn, total solids, 53.
corn pollen from corbicula total solids 66.94. Stored pollen from hive total solids 79.66.
Pollen direct from corn, moisture 46.53.
Corn pollen from corbicula, moisture 33.06.
Stored pollen from hive moisture 20.34.
Pollen direct from corn, reducing sugar before inversion, 2.87.
Corn pollen from corbicula, reducing sugar before inversion 11.07.
Stored pollen from hive, reducing sugar before inversion, 17.9.
Pollen direct from corn, sucrose, 2.77.
Corn pollen from corbicular, sucrose 3.06.
Stored pollen from hive, sucrose 2.25.
Pollen direct from corn, total reducing sugar after inversion 5.79.
Corn pollen from corbicula, total reducing sugar after inversion, 14.29.
Stored pollen from hive, total reducing sugar after inversion, 20.27.
Pollen direct from corn, dry basis, reducing sugar, 5.37.
Corn pollen from corbicula, dry basis, reducing sugar, 5.37.
sugar, 16.54. Stored pollen from hive, dry basis reducing sugar, 22.47. Pollen direct from corn, dry basis,
sucrose, 5.18. Corn pollen from corbicular, dry basis sucrose, 4.57. Stored pollen from
dry basis sucrose 2.82.
These analyses show conclusively that a very large amount of sugar has been added to the pollen by the time it reaches the corbiculi.
Calculated on a dry basis just about twice as much sugar is present in the basket pollen as in that from the corn plant.
Not only is this so, but the additional fact is disclosed.
that over three times as much reducing sugar is present in the corbicular pollen as sucrose.
This latter result indicates that honey, largely a reducing sugar,
rather than nectar containing more sucrose, is the chief sugar ingredient of the corbicular pollen.
The additional amount of sugar, here again a reducing sugar,
in the stored pollen of the hive, is what,
might be expected, since it is supposed that the workers add honey and possibly other ingredients
to the pollen within the storage cells.
The total solid percentages corn 53.47, corbicula 66.94, stored pollen, 79.66, also show that
the fluid substance, which is added, is one highly charged
with solids, a condition which honey amply fulfills.
In the descriptions which have been cited of the pollen-gathering process
in which the mouth is supposed to supply the requisite fluid,
three substances are mentioned.
Nectar, honey, and saliva.
The analyses herein given indicate that reducing sugar is mingled with the pollen,
and in the case of corn, it is indicated that,
honey is used in greater abundance. Without doubt, a certain amount of saliva also finds its way to the
pollen, but the proportion of this substance has not been determined. This salivary fluid may have
adhesive qualities, but this is scarcely necessary, since honey alone is amply sufficient for
this purpose. It appears probable that the fluid which a bee adds to the pollen, which it
collecting varies somewhat in amount since the pollen of different plants differs
considerably in moisture content and that of the same plant will differ in this
respect at different times. Pollin collected in the early morning before the
dew has left the plant is much more moist than that found upon the same plant later
in the day and the grains if taken when moist have a natural
tendency to become aggregated and form small masses.
Moreover, this may explain the fact that bees make their pollen collecting trips
during the morning hours, rather than in the afternoon, although some may be seen upon the
flowers throughout the whole day.
End of Section 8.
Section 9 of the behavior of the honey bee in pollen collecting.
This Librevox recording is in the public domain.
The Behavior of the Honeybee in Pollen Collecting by D.B. Castile
Section 9
Storing Pollin in the Hive
When the bee has fully loaded its baskets and before it returns to the hive,
it often spends a little time upon the plant from which it has been collecting,
occupied with the task of cleaning scattered grains of pollen from its body
and of patting down securely the loads which it has obtained.
Upon its return to the hive, it hurries within and seeks for a suitable place in which to deposit the pollen.
Some returning bees walk leisurely over the combs and loiter among their sister workers,
while others appear to be greatly agitated, shaking their bodies and moving their wings as though highly excited.
Many pollen-bearing bees appear eager to receive food upon their return to the hive,
and they will solicit it from other workers or take it from the honey-storage cells.
The workers of the hive at times take a little of the fresh pollen from the baskets of the laden bee,
nibbling it off with their mandibles or rasping off grains with their tongues.
If the combs of a colony are examined,
stored pollen will be found in various parts of the hive.
In the brood frames the greatest amount
is located above and at the sides of the brood
and between this and the stored honey.
Cells scattered through the brood from which young bees have lately emerged
may also contain pollen.
In the outer frames of the hive,
where brood is less likely to be found,
nearly all of the cells may be packed with pollen,
or honey-stored cells may be found interspersed with those filled with pollen.
As a rule, pollen is not stored in drone comb, although this occasionally happens.
As the pollen-bearing bee crawls over the comb,
it appears to be searching for a suitable cell in which to leave its load.
It sticks the head into cell after cell,
until finally one is located which meets its requirements although it is an open question as to why any one of a group should be chosen rather than another
this selected cell may already contain some pollen or it may be empty if partly filled the pollen which it contains is likely to be from the same species of plant as that which the bee carries although different kinds of pollen are often stored in the same
cell. In preparation for the act of unloading, the bee grasps one edge of the cell with its
four legs and arches its abdomen so that the posterior end of the abdomen rests upon the
opposite side of the cell. The body is thus held firmly and is braced by these two supports
with the head and anterior thoracic region projecting over one of the neighboring cells.
the hind legs are thrust down into the cell and hang freely within it the pollen mass is being held on a level with the outer edge of the cell or slightly above it
the middle leg of each side is raised and its planta is brought into contact with the upper or proximal end of the tibia of the same side and with the pollen mass the middle leg now presses downward upon the pollen mass
working in between it and the corbicular surface,
so that the mass is shoved outward and downward and falls into the cell.
As the pollen masses drop, the middle legs are raised,
and their claws find support upon the edge of the cell.
The hind legs now execute cleansing movements
to remove small bits of pollen which still cling to the corbicular surfaces and hairs.
after this is accomplished the bee usually leaves the cell without paying further attention to the two pellets of pollen although some collecting bees will stick the head into the cell possibly to assure themselves that the pollen is properly deposited
it has been stated by some cheshire for example that the spur upon the middle leg is used to help pry the pollen mass from the corbicula
this structure is in close proximity with the mass while the middle leg is pushing downward upon it but its small size renders difficult an exact estimate of its value in this connection
it is certainly true that the entire planta of the middle leg is thrust beneath the upper end of the pollen mass but the spur may be used as an entering wedge
pollen masses which have been dropped by the collecting bee may remain for some time within the cell without further treatment but usually another worker attends to the packing of the pollen shortly after it has been deposited
to accomplish this the worker enters the cell head first seizes the pollen pellets with its mandibles breaks them up somewhat or flattens them out probably mingles additional flukels
fluid with the pollen and tamps down the mass securely in the bottom of the cell.
As is shown by the analyses of corbicular pollen and of stored pollen,
certain substances are added to the pollen after the collecting bee leaves it in the cell.
Sugar is certainly added, and it is generally supposed that secretions from some of the salivary glands
are mixed with the pollen after deposition.
It appears probable that the stored pollen or bee bread is changed somewhat in chemical composition
through the action of the fluids which have been added to it, either during the process
of collection, at the time of packing, or later.
End of Section 9.
Section 10 of the behavior of the honey bee in pollen collecting.
This Librevox recording is in the public domain.
the behavior of the honey bee and pollen collecting by d b castile section ten summary pollen may be collected by the worker bee upon its mouth parts upon the brushes of its legs and upon the hairy surface of its body
when the bee collects from small flowers or when the supply is not abundant the mouth parts are chiefly instrumental in obtaining the pollen
the specialized leg brushes of the worker are used to assemble the pollen collecting it from the body parts to which it first adheres and transporting it to the pollen baskets or corbiculi of the hind legs
in this manipulation the forelegs gather pollen from the mouth parts and head the middle legs from the fore legs and from the thorax the hind legs from the middle legs and from the abdomen
the pollen baskets are not loaded by the crossing over of one hind leg upon the other or to any great extent by the crossing of the middle legs over the corbiculi
the middle legs deposit their loads upon the pollen combs of the hind plantie and the plantee in turn transfer the pollen of one leg to the pectin comb of the other
the pectin of one leg scraping downward over the pollen comb of the opposite leg a little pollen is loaded directly from the middle legs into the baskets when these legs are used to pat down the pollen masses
aside from the foregoing exception all of the pollen which reaches the baskets enters them from below since it is first secured in the pectin combs and is then pushed upward by the impact of the rising oracles
which squeeze it against the distal ends of the tibbe and force it on into the baskets to meet that which has gone before the long hairs which form the lateral boundaries of the baskets are not used to comb out pollen from the brushes of any of the legs
they serve to retain the accumulating masses within the baskets and to support the weight of the pollen as it projects far beyond the surfaces of the tibbeye
pollen grains are moistened and rendered cohesive by the addition to them of fluid substances which come from the mouth analyses show that honey forms a large part of this moistening fluid although nectar and secretions from the salivary glands are
probably present also. In the process of pollen manipulation, this fluid substance becomes well
distributed over the brushes of all of the legs. The four legs acquire moisture by brushing over the mouth
parts, and they transfer this to the hairs of the breast and to the middle leg brushes
when they come in contact with them. The middle leg brushes transmit their moisture to the pollen combs
of the hind legs when they rub upon them.
All of these brushes also transport wet pollen,
which has come from the mouth parts,
and thereby acquire additional moisture.
The oracles and the planty of the hind legs
become particularly wet from this source,
since fluid is squeezed from the wet pollen
when it is compressed between the oracles
and the distal ends of the tibbe.
Dry pollen, which falls upon,
on the body hairs becomes moist when brought into contact with the wet brushes or with wet pollen.
During the process of manipulation, pollen passes backward from its point of contact with the bee
toward its resting place within the baskets.
Pollin which the collecting bee carries to the hive is deposited by this bee within one of the cells of the comb.
as a rule this pollen is securely packed in the cell by some other worker which flattens out the rounded masses and adds more fluid to them
end of section ten end of the behavior of the honey bee and pollen collecting by d b castile p h d
