Bees are found almost everywhere, sometimes in surprising places. There are approximately twenty-five thousand species of bees in the world, about thirty-five hundred species in North America, and even in the middle of New York City's Central Park more than sixty species have been identified. Scientists have always distinguished one species from another by observing the details of their mouthparts, wing veins, size, body hair, tongue, and pollen-carrying structures, and by their nesting and foraging behaviors. Now that DNA analysis is available as an additional tool, relationships and differences among species are being further clarified.
Honey bees are a social species, living in large, perennial colonies headed by a queen. They are by far the most economically important bees in the United States. Historically, populations of native bees have been negatively impacted by various land-use practices - this history, as well as the solitary nature of most native species, means that honey bees have become the pollinator of choice for many agricultural crops.
Approximately 85 percent of bees are solitary species, meaning that a single female emerges from her pupal case, mates, and then constructs one or more individual cells that she provisions with nectar and pollen. She may burrow into the ground to make her nest, or she may create a cell in an existing hole in a tree, plant stem, or other material. Then she lays an egg directly on the food supply, and the egg develops into an adult bee that repeats the cycle. When there are limited areas in the habitat that are suitable for nesting, hundreds or even thousands of solitary bees may nest in close proximity. Male solitary bees usually are short-lived, whether they mate once or several times.
Bumblebees are native to the United States and are distributed on many other continents as well. Their colonies are relatively small. Only the queen survives the winter, and although she is larger than the female workers, her body structure is basically the same as that of the workers. She needs to forage when the warm weather arrives because she is the only bee alive in the nest, which differs from the honey bee queen, who never needs to forage because she is always surrounded by attendants. Although bumblebees forage for pollen and nectar to feed their young, they make very little honey and it cannot be harvested by people. Stingless bees evolved earlier than honey bees, and they are found in the tropics on every continent, strongly suggesting that they evolved before the continents separated approximately seventy million years ago. They nest in cavities, usually inside a tree trunk or in a branch; some nest inside the nests of other insects, such as ants or termites.
Giant honey bees are found in Asia, and they make large nests out in the open that hang from tree branches or rock overhangs. They nest gregariously, with the result that there can be as many as a hundred individual nests in the branches of one tree. Their nests are often depicted in prehistoric rock paintings. Many solitary species belong to the family Halictidae and are typically called sweat bees because many of them are attracted to the salts in human perspiration. After the halictid female mates, she builds her own small nest in the soil or in a small enclosure within a plant stem, dead tree, or sandy embankment. She gathers pollen and nectar, combines them, deposits a pellet of this paste in each cell and lays an egg on each bit of food. Then she usually dies and her offspring emerge and repeat her pattern. Sweat bees are small and dark colored, often with lightcolored bands of hair or a metallic sheen to their body. Some species may help each other and even share a nesting tunnel, but most do not cooperate.
Mining bees are considered "semisocial," characterized by their soil nests with branching chambers. At the end of each chamber are one or more cells. There is some group organization but there is no definite caste system and no queen, and they are less social than sweat bees. Leafcutter bees have long tongues and carry pollen on their abdominal hairs, known as scopa. Females make thimble-shaped chambers of folded leaves along a tunnel in the ground or in a hollow plant stem, and they accumulate honey and pollen and lay an egg in each chamber.
Close relatives of the leafcutter bees are mason bees, which nest in nail holes or other pre-existing cavities in wood. They fill each hole with honey and pollen and then lay an egg in it and cap it with mud. These females can produces one or two eggs per day. Cellophane bees, also called plasterer or polyester bees, nest in soil burrows or in twigs and plant stems, depending on the genus. One genus, Hylaeus, is relatively hairless and looks somewhat wasp-like. Instead of secreting wax, bees in this family line their brood cells with a secretion that hardens into a cellophane-like membrane.
Carpenter or digger bees are hairy and fast flying and typically nest in the ground or build a nest in wood. They carry pollen on their legs, and they have long tongues and are excellent pollinators. One common species of carpenter bee in the eastern United States resembles the bumblebee in body size and coloration, but carpenter bees are solitary while bumblebees are social in small colonies that are founded by one queen.
Parasitic bees, which belong to many different families, do not forage for nectar or make their own nests, and they are not equipped to gather pollen. They invade the nests of other bees and lay their eggs in the nests of their hosts. When their larvae emerge, they feed on the stored food that was meant for the host larvae. These parasites may go so far as to kill the eggs or larvae they find in the nest. Some species of parasitic bees invade a colony and kill the queen, and then they lay their own eggs in the host's cells and force the host workers to raise the young parasitic bees. Vulture bees are a special type of stingless bees, first identified in 1982 by David Roubik, now at the Smithsonian Tropical Research Institute. They seek out rotting carcasses and ingest their body fluids, which they process using saliva. They take this substance back to their nests, and, like nectar, it is passed to storer bees and transformed, and eventually it is fed to larvae.
Our website is not responsible for the information contained by this article. Articleinput.com is a free articles resource thus practically any visitor can submit an article. However if you notice any copyrighted material, please contact us and we will remove the article(s) in discussion right away.
Note: This article was sent to us by: Albert R. Nichels at 08152010
1. Synergistic actions of growth hormones
All articles are property of their respective authors. Please read our Privacy Policy!
© 2009 ArticleInput.com.
Partners: Damenmode