Honeybee Theory | Fattoria Didattica biologica

Honey bee Theory

Order: Hymenoptera (from the Greek ‘Hymen’ and ‘Pteron’ meaning wings)

Bees are social insects and among the most valuable to humans. As a producer of honey and wax, and a pollinator to numerous wild and cultivated plants (fruit and nut trees, vegetables, and feed plants), the honeybee can only survive as part of a community known as a colony, nest, or hive. The importance of the honeybee for the agriculture of industrialized nations can be illustrated by the fact that more than 50 species of cultivated plants (both vegetable and fruit) depend completely or partially on this insect for pollination. In fact, these plants have pollen too sticky and too heavy for dispersion by wind. Honeybees are the only insect that can survive on pollen under the precise scope of pollination.

The honeybee can navigate the deep, dark tunnels of its hive thanks to two external antennae which provide a very particular vision; perceiving colours invisible to the human eye, such as the ultraviolet. The olfactory glands allow the bees to recognize odors specific to various members of the hive. Unlike other species of Apoidea, honeybees do not hibernate.

The honeybee is subject to various bacterial and viral maladies, such as bee plague, a malady contagious to larvae. Adult parasites include mites and louses. Other nemeses of the bee are predatory insects and birds. In addition, there are various harmful insecticides used to protect crops from pests.

A community of bees is comprised of three diverse structural castes: queen (female), drone (male), and worker (sterile female) – the latter possessing specialized instincts which are associated with diverse functions inside the colony. The queen and her workers cooperate for the benefit of the hive. The perfection and ordered development of a bee community represents a fascinating example of social organization, with diverse jobs according to the roles (and the ages) of different bees. At the center of all this activity is the queen, the sole producer of the pheromones (chemical substances that influence the behavior and the development of other individuals of the same species) that assures the continuance of the life of the colony.

The queen is the only fertile female in the entire community and thus is the mother of all the drones, workers, and of the future queen. Her capacity to lay eggs can be astounding: usually she will produce more than 1,500 eggs in a day. The queen has the ability to control the sex of her brood. When an egg passes from the ovary to the oviducts, it may or may not be fertilized by sperm from the spermateca: a fertilized egg develops into a female - worker or queen – while an unfertilized egg then produces a drone. The queen deposits the eggs which will develop other queens into specific cells. These cells hang from the ceiling. The royal jelly, which has a pasty consistency, is placed in cells in sufficient quantities to feed the larvae as well as to prevent them from falling. They develop from egg to adult in 16 days, at which point the queen is very anatomically different from the drone or the worker. Her body is longer, with a more voluminous abdomen, than the sterile female workers. Her mandibles are armed with sharpened teeth, of which the drones are deprived. The queen also has a sharp and curved stinger, which may be used multiple times in her life. The queen is privy to the same “working instruments” as the workers. The queen feeds on an exclusive diet. It is based on a secretion, the royal jelly, produced by the hypopharyngeal glands situated in the head of the worker bee. The average life of a queen bee is between one and three years.

The drone, which takes 24 days to transform from egg to adult, is unarmed and deprived of stinger; it does not have pollen castles, neither does it have glands for wax or for royal jelly. Their sole function is to mate with the new queen. Once the queen leaves the hive, it is literally attacked by drones waiting naked outside. The coupling, which is always held outdoors, is so impetus that some of the drones leave their genital fixtures in the body of the queen and die soon after. In contrast with the first studies on honey bee reproduction, which stated that the queen mates only once in her life, more recent research has suggested that she usually mates with six or more drones in only a few days. The mobile sperm of the drones make their way into a sac in the abdomen of the queen known as the spermateca. Here it can stay alive for as long as the queen lives. In a honey bee colony, the drones are most numerous during spring and summer, but in the approach of autumn the workers chase them out of the hive and leave them for dead.

The worker bees are always more numerous than the drones. In spring, in one colony in a temperate region, there can be between 8,000 and 15,000 worker bees and upwards of 80,000 worker bees. While lacking the capability to mate and reproduce, they excrete wax; allowing them to construct the hive and to keep it clean and, when necessary, to defend it. They collect water, pollen, and nectar which they ultimately transform into honey. For all three castes of bees the pollen represents the principle source of protein, fats, vitamins, and minerals necessary for growth and development. Once mature, the bees can live only on honey or sugar, a diet based exclusively on carbohydrates. The worker bees have at the tip of their abdomen a stinger covered with barbs. This is provided with venom from an interior gland which, when used, remains stuck in the flesh of the victim. Furthermore, while trying to free the stinger, they tear an abdominal lesion, which causes them to die shortly after. The stinger of the worker bees seems to have evolved over time from a duct for depositing eggs, having developed to compensate for what the drones lack. The working instruments given to the worker bees are:

In addition to collecting and storing food for the other community members, the workers are also responsible for defending the colony. Moreover, when the hive becomes overheated, they create air currents by collectively beating their wings; if the hive becomes too cold they will group near the larval cells to create needed heat. In this fashion they precisely maintain an optimal temperature (34°C) in the larval cells for the hatching of eggs and development of larva. Like many other insects, before becoming adults the bees undergo a metamorphosis. Worker bee eggs are deposited in horizontally oriented cells smaller than those used for drones or queens. Three days after the eggs are deposited in the cells they transform into larva which are fed by the workers for six days (royal jelly for the first two days and later with pollen, nectar, or honey).

On the sixth day, the cells are enclosed into waxen capsules while the larval rows of cocoons develop into nymphs or pupae. On the 21st day the worker bees are ready. They punch through the wax and begin life as adults. Each of the hundreds of larvae contained in the hive have to be nourished many times a day, and the different anatomies and physiologies between the workers and the queens require different foods during each larval stage. For the first three weeks of their adulthood, the workers stay inside of the hive, and in the first days of life they are restricted to cleaning the cells. After the 12th day of life they begin to provide food for the young as well as royal jelly for the queen with their nutritive glands, and from the 12th to the 20th day of life, while the nutritive gland is running dry, they begin to produce wax from their wax glands to make walls to construct the honeycomb. The young bees, which do not leave the hive, are the ones occupied with maintaining the temperature and evaporating nectarous water.

Around the 12th day, they make their first flight in order to recognize - and memorize - the position of the hive, but only after the 20th day may the workers fly out into the open and begin work as foragers (collectors of pollen and nectar) if they are not made to remain in the hive to defend it from external attacks. The foragers (which travel more than 100 km a day at a maximum velocity of 25 km/hr) also have the job to collect water and dew necessary to dilute honey or pollen and to regulate the temperature of the hive and propolis (a resinous substance found in tree shoots that is used in the hive as a sealant and an antiseptic). The foragers collect the nectar of many different flowers then return to the hive with their sacs full. They then regurgitate through their mouths to a young workers, and after the evaporation of excess water, it is transformed into honey. When the honey is thickened and ready, the cell is sealed shut with wax to keep out the air, where it is kept as winter rations.

The pollen brought into the hive in the hind legs of the forager and placed directly in appropriate cells is derived largely from a floral source and underlines a very important role of the forager bee: if the bee flies from one species to another, the transfer of pollen would be completely useless. But instead, each trip is limited to flowers of one single species, and thus provides cross-pollination, necessary for the reproduction of many varieties of plants. To produce honey and wax, the bees must spend their lives flying among flowers in open air. Their delicate bodies are exposed to cold and bad weather, against which the bees must generate sufficient heat not to freeze when the temperature drops too low. In order to combat this problem, the worker bees must store a sufficient quantity of food to outlast the entire winter during only the summer months. One day of fasting can be lethal for a bee. The workers that develop at the beginning of the season have an intense life which, from birth to death, lasts about six weeks. The worker bees that hatch later, however, live longer, and in winter have no other occupation than to collect food and make heat.

The worker bees have a refined system of communication, described in detail since the beginning of the 20th century by the Austrian zoologist Karl von Frisch. In an already classic article, published in 1923, von Frisch describes the fashion in which, when a forager discovers a new source of food and returns to the hive full of nectar, it begins an energetic dance with recognizable moves, which is repeated invariably: if the new food source is closer than 90 meters from the hive, the bee follows a “round” dance. In this dance, the bee walks in circles, often inverting the direction: a moment clockwise and then a moment counter-clockwise; even in a darkened hive numerous bees flock to the dancer. In this way the other bees understand that the food is not far from the hive and can identify the natural perfume of the nectar.

Once the rite ends, the other bees leave the hive and fly in the indicated direction - flying always wider - until they find the new food source. The new food source is further from the hive, the forager follows a more elaborate dance, the “waggle” dance: the bee agitates its abdomen as it moves straight, then circles back around in a figure 8 movement on alternating sides of the straight line. Each movement of this dance seems to have a precise significance. The number of wiggles completed in each interval informs the other bees of the distance of the food source, the more frenetic, the closer the food. The orientation of the circle indicates the direction of the food: if it points straight up, the food is in the direction of the sun; if it points down, it is the opposite; if it points diagonally, the bees search a long course in that specific angle with respect to the sun. This information provided by the bees is so clear that a trained researcher is able to understand from simple observation.

Beekeeping is the raising of colonies of honey bees for pollination of agriculture as well as for honey and other products. Practiced since antiquity and diffused throughout the globe, beekeeping seems to have originated in the Middle East and was practiced by the ancient Egyptians, who raised bees and sold honey and wax along the eastern coast of Africa. For centuries the beekeepers harvested the honey and wax while killing the colonies of bees that lived inside the hive. It was not until 1851 that the American beekeeper Lorenzo Lorraine Langstroth discovered that the bees leave the honeycombs apart by a space of about six millimeters. This space, artificially maintained in the hive with an adjacent frame - even if it is the last wall of the hive - makes it possible to remove a single frame from the hive and harvest the honey and wax without disrupting the colony. This innovation permits a simple yet effective control of the maladies of the insects and fosters a greater number of colonies.

Although many beekeepers do live off of the products of their bees, the most important economic contribution offered by the honey bee is their pollination of various species of vegetables, fruits, and herbs.

Bees have to be raised in an area where there is an abundance of nectar-producing plants. Since it is not profitable to cultivate plants solely for the production of honey, apiaries are usually developed where there is already some form of intensive agriculture. To have a good return there should be at least 30 to 50 colonies.

Every year insecticides and pesticides kill and weaken millions of colonies. The honey itself is, susceptible to pollution. If the source of food for the bees is impure, the colony is killed or gravely weakened and cannot produce the surplus normally harvested by humans.

China, Mexico, and Argentina are the major exporters of honey. Germany and Japan are, the major importers. Russia produces about a fourth of the total world honey, which is not, however, brought to the international honey market.

The sugary solution is often very sweet. It is produced by other species of Apoidea for feeding their larva and as reserve food for their own survival during winter. Flower nectar is extracted by worker bees and is then transformed into honey inside of a special sac containing their own digestive apparatus. It is then stored in honeycombs on the inside of the hive. Bee’s honey is an important element in the diet of many animals, such as the bear and the badger, as well as the human. Some types of ants and aphids produce a substance similar to honey, beginning with elements present in flowers, in the resinous excretions of the plants or in the sweet secretions of other insects. Bee’s honey is composed from fructose, glucose, and water in variable proportions; containing, also, other enzymes and essential oils.
The color and taste of honey depends on the source from which the nectar was obtained and the age since it was made. Honey of clearer color is deemed more precious than that which is dark. Among the types of honey available in Italy there are: acacia or black locust honey, rather liquid, straw-yellow with a green tint, typical to the alpine foothills of Liguria and Piedmont; citrus honey, typical of Sicily, Calabria, and Sardinia, spreadable, but also with large grains (crystallizations); eucalyptus honey, produced in the south central regions and also in Sardinia, liquid, the color of clear amber (and becomes even clearer with crystallization); chestnut honey, diffused throughout Italy, the color of clear ochre with reddish tints, with a very intense taste, with a bitter aftertaste. Honey contains a caloric value equal to 3307 cal/kg. Since it easily absorbs humidity, honey is used as a dehumidifying agent for tobacco. Kept at room temperature, the glucose tends to separate into a layer crystals over a layer of liquid fructose. The honey must stay in the original honeycomb or be extracted with a centrifuge; in which case it is called “centrifuged honey”. Sometimes jars of liquid honey leave a suspended piece of the honeycomb.

Bees build their honeycombs out of wax, which comes from a gland with two transparent membranes in the shape of irregular pentagons and located near the back of the abdomen, which can be observed with the naked eye (these wax-secreting organs are true glands, providing canals to intake the liquid to be transformed into the greasy substance). In ancient times it was believed that the wax was the development of a pollen product undergone in the bees, and as such considered an herbal substance. But, it is an animal substance. The bees produce the wax even if they are fed only with honey or sugar syrup. The virgin wax of our bees is a hydro-carbon fat, containing a principal coloring, a waxy acid, and a dense oil called myrcina. It melts at 63° or 64°, soaks at 35° - water is lighter and the wax is insoluble in it - and the specific weight is 0.966. It dissolves in alcohol and if reduced, it is stripped to gasoline and oil.

It could also be saponificated caustically. The wax provides (from dissociation of the sugary substances) a conversion into a fatty substance. When the bees want to produce wax, they initiate a chemical reaction with heat development. Oxygen in the air introduced into the body of the bee. It is then associated with hydrogen and carbon sugars already present in the hive, as such forming water and carbonic acid. The heat is given off by the conversion of the two gasses into liquid state with the by-product of water. When the bees want to produce wax for constructing honeycomb inside a hive, they stuff themselves full of honey and pollen (which they need, as carnivores need meat, not to exhaust themselves). To do this they need a place to rest and a high amount of calories to produce the heat by respiration and to dissolve the sugary substances, which are reassembled while the bees form festoons hanging from above. In these conditions they remain immobile for 24 hours, sufficient time for a complete digestion, and when they are ready they peel off the glom to begin work on wax cell construction using flakes of wax scraped from the wax glands and carried in the mouth to soften with saliva. The wax production happens mostly during the night when the entire family is present as to include not only the young but also the adults, who are more adapted to wax production on hot, humid nights.

Waxes can also be made from vegetables and minerals, first observed on the leaves of cabbage, on the flowers of prunes, and on the peduncles of hops flowers. Palm wax can be harvested from ceroxylonandicola in large amounts. Mineral wax (also called resin) is obtained from the purification of the residues of various heavy mineral oils and also from parts of oils able to be crystallized. This wax is translucent and less transparent than beeswax. At times this is used as an additive to beeswax to increase the weight. Bees refuse to work with adulterated wax leaves and will often destroy them to make honeycomb in their own method though losing energy and precious time.

An elementary illumination device, generally made of a cylinder of wax or other materials which combust at the lowest flash point. From the inside protrudes a wick made of cotton or other fibers. Imbuing the capillaries of the wick, the combustible material burns with a luminous flame. The Romans used beeswax candles, while in medieval Europe tallow (cow or sheep fat) was common. In the 18th century they used spermaceti, a wax obtained by refining whale’s oil, which at the middle of the 19th century became a substitute for paraffin, stearin (ester of stearic acid), and beeswax. Today, hydrogenated vegetable oils and other types of wax are used. Wax candle making methods:

Immersion candles. This is the oldest candle making method and consists of immersing the wick (generally linen or cotton fibers) in melted wax (or tallow). It is extracted and left to cool by air or in water after which it solidifies and can be dipped again repeatedly to obtain the desired dimensions. In this way, immersion candles are nothing but an enlarged wick. This is a very simple method, and in one step, two candles can be made at a time by soaking two ends of the wick and then immersing in a basin of water as to keep the wax lucid. When the candles are finished the wick is cut leaving a few centimeters. The bottom of this type of candle is never flat enough to rest vertical without the use of a pricket, and today this artisanal process is only used for candles that are long and thin.

Rolled candles. Rolled candles are the easiest to make, requiring only a knife, a ready-made wick, a hairdryer, and sheets of beeswax. Using a rectangle of wax, the wick is placed on the length of one side of the sheet and adhered with the heat of the hairdryer. Then it is rolled. The wax sheet is on the outside of the wick and pressed into one compact strata without breaking the one same sheet of wax.

Stamped candles. These are made with an automatic process involving a metal die. A vat of wax is melted and then poured into the desired mold (which already has the wick vertically inserted). To cool the wax more efficiently, and to allow the finished candle to be removed easily, the mold can first be wetted with soapy water.

LAB PLAN: Observing the bees and making candles
Instructor's Guide
Organized for 25 participants
This lab lasts for about 2 hours and is divided into 3 parts:

How candles are made: immersion candles, rolled candles, and stamped candles (see theory)