Bees

Get Creative in the Garden with Bryn — By on October 2, 2008 12:40 PM

Until recently, most of us have been fairly unaware of bees and their activities, with the possible exception of occasionally being concerned that we might be stung by a nearby bee. With the rise of Colony Collapse Disorder, suddenly bees are regularly in the news. What do we know about these creatures and why are we so concerned by their disappearance?

Bees are a winged insect, having 3 distinct body sections (the head, thorax and abdomen), 3 pairs of legs and 2 sets of wings. Bees have 2 compound eyes, which are excellent at detecting movement, and 3 small, simple eyes called ocelli, which detect light intensity. There are nearly 20,000 known species of bees world-wide, in nine recognized families. With the exception of one small sub-group of bees (‘vulture bees’), which feed on carrion, all bees depend on flowers for their food source. Bees can generally be divided into two groups, solitary bees and eusocial bees (although a few species of bees form small social groups.)

Solitary bees emerge from their nests as adults and promptly leave in search of food. Males typically leave first and wait near nectar sources for receptive females to arrive. After mating, the males will die and the females will go in search of a nest site where she will construct a series of cells. In each cell she places a food package she has created from nectar and pollen and then lays an egg on top. She has to make a number of foraging trips in order to create enough food packets. She then seals the cell and leaves the nest after filling all the cells. She typically creates several nests during her lifetime. When the larvae hatch, they remain in the cell eating the food left for them. After becoming adults, they chew their way out of the cell and leave the nest. Most of the native bees in the US (except for bumblebees) are solitary bees.

Eusocial groups are defined as highly organized social groups with hierarchical division of labor, overlapping generations and cooperative care of young. Both honeybees and bumblebees are considered eusocial bees and their colonies are generally what we think of when we think of bees. Their complex societies have been well studied. A colony will contain a single queen, many workers and a lesser number of drones. A queen’s sole purpose in life is to reproduce. She tends to be the largest bee in the colony. The queen bee will typically leave the colony shortly after maturity to mate with a number of males. This may be the only time she leaves the colony. She will store sperm from this one mating flight to use the rest of her life-2 to 7 years. She will lay up to 2,000 eggs a day-more than her body weight. A worker bee is a non-reproductive female. They make up the vast majority of the hive and may have a number of jobs during their life: food collecting, caring for the queen, guarding the colony, caring for the young, cleaning, controlling temperature of the hive via water evaporation, etc. A drone is a male bee whose sole purpose is to mate with the queen. Drones can be recognized by their extra large eyes-necessary because they mate with the queen in flight, often up to 100 feet off the ground. Drones are cared for their whole life by the worker bees, but a drone that successfully mates will die from the process. Drones may also be evicted from the colony and left to die when food is scarce.

The queen determines the sex of an egg but the workers determine when a female egg becomes a new queen. If the colony suddenly loses its queen or if the reproductive rate of the queen slows, the workers will feed several larvae in larger cells a higher sugar and higher protein food they make called royal jelly. If the old queen is still around when the new queens mature, she will leave the colony with some of the workers to form a new colony. The new “virgin queens” will fight among themselves until only one remains in the nest. The remaining will either have left the nest or been killed. For more information on the roles and lifecycle of eusocial bees see Wikipedia (queens, workers, drones) or Nova’s The Anatomy of the Hive.

As you would expect, to maintain a complex system like a bee colony, eusocial bees have developed elaborate methods of communication. Most communication is achieved by pheromones, but this method is best when the message is straight-forward, such as when one new queen announces that she is victorious or when the hive needs to be cooled. Worker bees also create complex dances to tell other workers when they find a rich food source. They can communicate direction, distance, and richness of the source via dance (and they will share the odor of the flowers too.) This dance is performed on a specially designated dance space just inside the entrance to the colony. To see videos of bee dances, check out Nova’s Dances with Bees.

We primarily associate bees with honey. Honey is created by bees from nectar. When a worker bee visits a flower, she sips the nectar (a sugary fluid includes the aromatic oils that give flowers their scent) through her proboscis and stores it in her honey stomach. She can store about 40 milligrams at a time. She will then return to the hive where she regurgitates the contents of her honey stomach to another worker bee who will either distribute it for immediate consumption or will process it into honey and store it in special honey cells. Nectar is about 70% water and honey is only 20% water. To process the nectar into honey, the worker will repeatedly swallow and regurgitate it as well as fan it with her wings. This process also adds enzymes from the bee’s mouth while retaining the sugars and aromatic oils originally found in the nectar.

Some interesting honey facts:
– In the course of her lifetime, a worker bee will produce 1/12th of a teaspoon of honey.
– To make one pound of honey, workers in a hive fly 55,000 miles and tap two million flowers.
– In a single collecting trip, a worker will visit between 50 and 100 flowers. She will return to the hive carrying over half her weight in pollen and nectar.
– A productive hive can make and store up to two pounds of honey a day. Thirty-five pounds of honey provides enough energy for a small colony to survive the winter.
– Honey’s flavor and color depend on the flowers from which the bees harvested their nectar.
– The pH of honey is between 3.5 and 4. In other words, it’s slightly acidic – about as acidic as orange juice – which discourages the growth of bacteria.
– Honey is hygroscopic, meaning that it can draw moisture from its surroundings, and it has a high osmotic pressure. Bacteria that come into contact with honey undergo plasmolysis (lose their moisture content to the surrounding honey) and die.
– Although honey is generally very good at killing bacteria, there is one notable exception — spore-forming bacteria, like Clostridium botulinum, which causes botulism. The amount of botulism spores in honey is generally not dangerous to adults, but it could be deadly to infants under one year of age. Feeding infants honey is not recommended.
– Humans have been harvesting and using honey for more than 15,000 years. Honey hunting is depicted in rock art in Africa, India and Spain. Egypt, Greece, Italy and Israel developed organized beekeeping centers until the Roman Empire dissolved in approximately 400 A.D. Christian monasteries and convents then served as apiculture centers until Henry VIII closed them at the beginning of the Reformation.
– The average American consumes a little over one pound of honey a year.

While visiting a flower, a worker bee also collects pollen and packs it into specialized storage areas (located on the legs of most bees, but the abdomen of some species.) Pollen is an important source of vital amino acids, vitamins, and fats for bees. It is stored in special pollen cells near the brood cells. Nurse bees will later fashion the pollen into a kind of “bread” for supplying nourishment to developing larvae.

Next Issue: Commercial Beekeeping & Colony Collapse Disorder

Happy gardening!

Bryn Richard is a licensed landscape architect with a strong interest in sustainable design. She can be reached at Bryn@BlueTrillium.net and welcomes your questions and suggestions for further articles.

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