The Lives of Bees
“If the bee disappeared off the face of the Earth, man would only have four years left to live.” This quote is generally attributed to Albert Einstein, although there is some dispute over its author. Nevertheless, it is a profound and unsettling statement and certainly gives us pause when we consider how dramatic it sounds and seems. It characterizes the interconnectedness of our world and the function of biodiversity for plants and animals to live and thrive. This unit will cover the lives and behaviors of bees to understand what they do, how they do it, and why their actions create an essential balance in nature.
Honeybees, bumblebees, mining bees, dwarf bees, carpenter, leafcutter, and mason bees: bees come in many different types, with more than 20,000 species worldwide. The bees we are most familiar with, bumblebees and honeybees, live in colonies and play a major role in pollinating the crops, plants, and flowers around us. Bees produce honey, a function of bees' lifecycle, which humans have utilized for millennia. The ancient Egyptians called bee pollen “the powder that gives life.” The nutritious mix of nectar, flower pollen, enzymes, honey, wax, and bee secretions were placed in their tombs to nourish them in the next life. Bees were seen as the servants of the gods, delivering messages and healing powers. In ancient Greece, bee pollen was called Ambrosia – the food of the gods. It was said to hold the power of immortality and eternal youth. Its health benefits were well established and both the father of modern medicine, Hippocrates, and the philosopher Pythagoras prescribed bee pollen for its healing properties. The Romans considered bee pollen to be a panacea. Roman soldiers carried dried pollen cakes with them to provide sustenance. The ancient cultures of China, India, and the Far East have the same references to the power and therapeutical benefits of bee pollen. To many, it was a necessary dietary staple. Native Americans, like the Romans, carried bee pollen in bags around their necks to give them energy on long journeys. In New Zealand, the Māori have a long tradition of using bee pollen for food.
Many bees today are domesticated, and beekeepers collect honey, beeswax, pollen, and royal jelly from hives for human use. Surprisingly, a typical bee produces a teaspoon of honey in her lifetime. Bees can communicate in many ways through the movement of their wings and bodies, most famously with the “waggle dance,” where they make figure-eight circles to let other bees know the direction and distance of nectar.2
Honeybees are considered super-organisms due to their complex social systems and dynamic, tight-knit interactions with one another and their environments. Colonies can number in the tens of thousands of bees, with 90 percent of them female worker bees who maintain the hive and population. There is a single queen, who can lay eggs for several years. Male drones are responsible for the fertilization of new queens.
Humans have kept honeybees in hives for millennia, yet only in recent decades have biologists begun to investigate how these industrious insects live in the wild. Thomas Seeley explains in The Lives of Bees what scientists are learning about the behavior, social life, and survival strategies of honeybees living outside the beekeeper’s hive―and how wild honeybees may hold the key to reversing the alarming die-off of the planet’s managed honeybee populations.
As a world authority on honeybees, Seeley describes why wild honeybees are still thriving while those living in managed colonies are in crisis. This is interesting as his research and suggestions show beekeepers how to use the principles of natural selection to guide their practices, and how beekeeping can better align with the natural habits of honeybees, a specific example of mimicking what nature does on its own.
Honeybees are the most important pollinators in most regions of the world where flowering plants exist but are by no means the only insects that play this role. Flies, butterflies, beetles, and other hymenopterans related to bees, such as solitary bees, wasps, bumblebees, and even ants can pollinate plants. Very few flowers are dependent on a single insect species, although no other pollinators are as effective as honeybees. In all, 80% of flowering plants worldwide are pollinated by insects, and of these about 85% by honeybees. As many as 90% of fruit tree flowers are dependent on honeybees. The list of flowering plants pollinated by honeybees includes about 170,000 species. 3
A single colony of honeybees may well visit several million flowers on a single working day. Because the bees inform one another about newly discovered areas of flowers, visits to all flowers are rapidly achieved. Hardly a single bloom remains unattended. Bees are also generalists that can cope with just about all flower types so that all have the same chance of being visited by bees.4
Pollination
Pollination is the transfer of pollen from the male parts of a flower to the female parts of a flower of the same species, which results in the fertilization of plant ovaries and the production of seeds. Flowering plants have existed for about 130 million years. Initially, the wind alone was the “postillon d’amour” (love’s messenger), and the sexual exchange was somewhat inefficient, requiring huge amounts of pollen to be dispatched on an uncertain and in most cases unsuccessful journey. In areas of limited or no wind, of course, this did not work at all.5
Because honeybees are efficient and effective pollinators of plants and flowers, they play a significant role in agricultural systems, increasing crop values each year by more than $15 billion in the United States alone and pollinating more than 80 percent of all cultivated crops.6 It has often been said that bees are responsible for one out of every three bites of food we eat. Most crops grown for their fruits, such as squash, cucumber, tomato and eggplant, nuts, seeds, cotton, and hay require pollination by insects. The main insect pollinators, by far, are bees.
Honeybees (Apis mellifera) are the most economically valuable pollinators of agricultural crops worldwide and are the only bee species kept commercially in the United States. In the United States, bee pollination of agricultural crops is said to account for about one-third of the U.S. diet, and to contribute to the production of a wide range of high-value fruits, vegetables, tree nuts, forage crops, some field crops, and other specialty crops.7
A number of agricultural crops are almost totally (90%-100%) dependent on honeybee pollination, including almonds, apples, avocados, blueberries, cranberries, cherries, kiwi fruit, macadamia nuts, asparagus, broccoli, carrots, cauliflower, celery, cucumbers, onions, legume seeds, pumpkins, squash, and sunflowers. Other specialty crops also rely on honeybee pollination but to a lesser degree. These crops include apricot, citrus (oranges, lemons, limes, grapefruit, tangerines, etc.), peaches, pears, nectarines, plums, grapes, brambleberries, strawberries, olives, melon (cantaloupe, watermelon, and honeydew), peanuts, cotton, soybeans, and sugarbeets.8
The tasks that honeybees must perform to effectively and efficiently use what is around them are many: recognize the flowers; distinguish between different kinds of flowers; recognize the state of the flower; know how to work the flower effectively with legs and mouth; determine the geographic location of the flower; determine the daily time window in which various flowers produce the most nectar; share the information with other field bees as a messenger in a communication system; receive and understand this information in this communication system of where to find flowers.9
Honeybees have the scientific name Apis mellifera, which means “honey-carrying bee.” They live in colonies of about 50,000 individuals in summer and about 20,000 in winter.10 Each colony occupies its own hive. Although there are tens of thousands of bees in a colony, there are only three types of bees: workers, drones, and queens.
The workers are the smallest bees, and all worker bees are sterile females. Thousands of them perform chores in the hive. They make honey, clean the hive, feed larvae (baby bees) and build the wax comb where all the bees live. Workers are the only bees that visit the flowers.11
Approximately one hundred male bees, or drones, live in each colony and serve only for reproduction, i.e., to mate with the queen. The largest bee is the queen. Each colony has only one queen, easily recognized by the longer abdomen, whose most important function is to lay eggs.12
In the summer months, workers live for about six weeks. They may live a bit longer in the winter as they are less active during the colder months. Drones live a bit longer in the summer months - about eight weeks. They generally leave the colony in the Fall and die. A healthy queen may lay for up to four years and lay over one million eggs during that time.
Honeybees survive the winter as a complete colony. The bees collect together in a dense cluster and keep themselves warm by vibrating their wing muscles. They use honey stores as the energy source for this activity.13
In the warm weather, a healthy queen lays one thousand to fifteen hundred eggs a day. Her “court” is formed of court bees who guard, clean, and feed her, exclusively with royal jelly, tending to her every need, and providing her with particular attention and care. Drones tend to be lazy, often not even feeding themselves. Worker bees will feed them.14
From Egg to Bee
A queen bee lays only a single egg in each comb cell, but up to 200,000 eggs each summer. Like many insects, a honeybee grows in four stages: egg, larva, pupa, and adult. The bee changes dramatically from one stage to the next.
Although all bees develop from the same four stages, the time it takes for each type of bee varies. Queens grow the fastest, in about sixteen days. Workers mature in twenty-one days, and drones in twenty-four days. Female bees develop from fertilized eggs, the larger male bees from unfertilized eggs.15
A queen lays a soft, white, oval egg at the bottom of a cell in the comb. In three days, a wormlike form called a larva hatch from the egg. Fed by worker bees, the larva grows much larger. Then the larva spins a cocoon. Inside the cocoon, a pupa develops from the larva. It starts to look more like an insect than a worm. It grows eyes, legs, and wings. Finally, an adult bee chews its way out of the cell.16
Stages of growth
Young worker bees constantly care for and feed the young larva. They feed royal jelly to the queen larvae. They feed bee milk to workers and drone larvae for the first three days and beebread after that.
Royal jelly is a milky, yellow syrup that young worker bees secrete from their glands inside their heads. It is high in protein. Bee milk is similar to royal jelly, but it is not as nutritious. It too comes from the glands in the worker bee’s head. Beebread is a mixture of honey and pollen.
During its first day, a larva eats so much that its weight increases five and a half times. For reference, if a child weighed 60 pounds on Monday, by Tuesday he would weigh 330 pounds.17
Inside the Hive
The comb is made of thousands of six-sided wax cells, built from wax that they produce from glands. They store honey and pollen in these cells of the comb and use comb cells as a nursery for their young.
Honey cells fill the top and circle the edge of the comb. Bees eat this honey for energy. Pollen cells curve below the honey cells. Pollen is powder taken from flowers that bees eat for protein, which helps their muscles grow stronger. Blood cells, where the worker and drone larvae are raised, are in the lower part of the comb. Queen larvae cups hang at the bottom of the comb.18
Honeybees are one of the few species of bees that live together in a colony - even bumblebees, social in the summer, reduce down to a single queen in the winter. They produce as much honey as they can in the summer when the flowers are blooming, to sustain them through the colder season.
In summer, the bees raise several young queens in specially constructed cells and feed them a special diet. Young queens mate only once in their lives, during their nuptial flight, but with many drones. 19
Honeybees swarm to propagate their colonies. The old queen leaves with a large proportion of individuals from the original hive (need to expand on swarming)
The Body of a Bee
When a worker bee crawls out of her cell, she is already fully grown. Even though she is one-half-inch long and weighs only 1/250 ounce, she contributes more than any other type of bee to the daily survival of the colony.
A honeybee has two kinds of eyes. Two compound eyes with over three thousand lenses each allow the bee to see ultraviolet light which is invisible to the human eye. With their ultraviolet vision, they can see which flowers are full of nectar. Antennae detect scents like a nose does and are used as feelers in the dark. A bee uses her front legs like arms to move flower parts and dust off her antennae. Her middle legs brush the pollen out of the thousands of branched hairs that cover her. Pollen baskets are on the outside of the back legs and are for storing collected pollen.
A bee can fly more than twelve miles an hour, going forward. She can also fly backward and sideways. A honeybee has two pairs of wings that can beat 250 times a second.
Like all insects, a bee has three sets of legs. A worker bee’s body is covered with branched hairs that trap pollen. Beeswax is secreted from the underside of the bee’s abdomen.
A honeybee has two stomachs The honey sac is where a bee stores nectar that will be made into honey. The midgut is where she digests her food.
A honeybee keeps her stinger hidden in the tip of her abdomen until she needs to defend herself or her hive. A worker’s stinger has barbs that prevent the bee from pulling it out from the target. As a result, a worker can only sting once. She flies away and dies because leaving the stinger behind damages her internal organs. 20
Figure 1: Honeybee side view |
Figure 2: Honeybee – top view |
House Bee
Worker bees pass through many occupational stages in their lives, for example, as cleaner bees, builder bees, brood care bees, and guard bees. Having reached seniority, they leave the nest as foragers. Brood care is the task of bees living within the hive. Foraging is the task of the bees that fly out of the hive.21
For the first three days of her adult life, a worker bee performs chores in the hive. Beekeepers refer to these workers as house bees. House bees clean the hive, feed larvae, build wax comb, store food, and defend the hive against enemies. No bee tells the house bee which chores need to be done. Instead, each bee is guided by an inner clock and does certain chores as she reaches a certain age. When a worker bee is first born, she cleans her cell and the cells around it. At three days old, she now feeds beebread to older drone and worker bee larvae. From about six to eleven days old, workers feed bee milk to the young drone and worker larvae and royal jelly to the queen. In the next several days, the bee’s wax glands are most active. Bees may hang from one another so that the wax flows more smoothly from their wax glands. Then, with her jaws, each bee shapes the wax into honeycomb.
Bees that are not making wax store food in the honeycombs. They deposit nectar (which will be made into honey) in the honey cells and pack pollen in the pollen cells.22
Field bee
In the summer, during the last three weeks of her life, a worker bee leaves the hive and flies through the fields, meadows, and gardens to visit flowers. The worker has been a house bee and has now become a field bee. She will make about ten journeys a day. Each flight takes about an hour and is within three miles of the bee’s hive. The first flight occurs before the dew dries from the flowers in the morning and the final flight of the day ends at sunset. During her trips, she gathers water, bee glue, nectar, and pollen, all of which the colony needs.23
Bees collect resin from the buds, fruit, flowers, and leaves of plants to make a caulking resin, called “propolis”, which they build into the hive. Humans use propolis from bee- hives for medicinal purposes, such as cold syndrome (upper respiratory tract infections, common cold, and flu-like infections), as well as dermatological preparations useful in wound healing, treatment of burns, and acne.24
Water is collected from small puddles and used to thin honey that is too thick. Droplets are placed inside the hive in hot weather. The bees fan the water which cools the hive as it evaporates. Bee glue sap, collected from flower buds, is stored in the bee’s pollen basket and used to seal cracks and varnish the inside walls of the hive. Bees gather nectar, the sweet juice from the flowers, and make it into honey. She sits still on the flower and uses her tongue to suck up the nectar. As she visits the flower and crawls around, pollen sticks to her antennae and branched hairs. She then hovers over the flower and brushes the pollen into the pollen baskets on her hind legs.25
How Bees Make Honey
Making honey requires field bees and house bees. A field bee collects the nectar, and returns to the hive, where the house bees take over the process. With her ultraviolet vision, field bees see dark shapes that indicate which flowers are rich in nectar. She lands on the flower’s petals and searches with her antennae for the sweet-smelling nectar. The field bee sucks up the nectar but does not digest it. When the field bee returns to the hive, she transfers the nectar to the house bee, who spreads the droplet of nectar on the roof of the honey cell where the nectar begins to dry. During the next couple of days, other house bees fan their wings over the honeycomb. Fanning evaporates the moisture in the nectar, which is 80% water. Honey is only 19% water. In the final step, other house bees cap the honey cells with a thin layer of wax. Inside, the thickened nectar ages and becomes honey. To make one pound of honey, a colony of bees collects nectar from over a million flowers!26
Honeybees communicate with one another through various chemical and tactile signals. The dance language is an important part of their communication system.27
Field bees show other field bees flowers are by dancing on their honeycomb in their hive. After the field bee has given the nectar to the house bee, she begins to walk rapidly in a circular pattern. Other bees gather and touch the dancing field bee with their antennae. By smelling the dancing bee, the other bees can tell what type of flowers she has visited. By feeling her movement, they can learn how far away the flowers are, and sometimes their location. There are several bee dances, but the most common ones are the round dance and the waggle dance. The round dance says “Flowers are close the hive” or less than one hundred yards away. The bee circles in one direction, then turns around and circles back in the other direction. The waggle dance says “Let me draw you a map, the flowers are further away” or at least one hundred yards away. The bee dances a half circle in one direction, turns, and runs straight while wagging her tail. Then she dances a half circle in the other direction. This elaborate dance shows both location and distance of the flowers, so the bees know exactly where to fly.28
The honeybee is the most important agent in the maintenance of flowering plant diversity.29
The biology of bee colonies and many flowering plants are tightly interwoven. Bee colonies produce daughter colonies with young queens carrying the female germ cells. Flowering plants produce fruit containing seeds. The uninterrupted flow of material and energy from the flowers to the bee colony enables the continuous replacement of the members of the hive, and thereby an “eternal colony” that brings forth a perpetual stream of daughter colonies.30
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