There are several reasons why honey bees are perhaps one of the most studied insects (probably next to Drosophila in terms of amount of money spent and number of papers published).
* Honey bees play a critical role in agriculture. The most important role honey bees play is actually not honey production, but pollination. The value of crops that require pollination by honey bees, in the United States alone, is estimated to be around $24 billion each year and commercial bee pollination was valued around $10 billion annually. There is also a trend to consume more bee-pollinated crops (such as fruits and vegetables), making honey bees more and more important in agriculture. Honey bees also produce honey and beeswax, which are valued at $285 million in US annually. Besides that bees also produce pollen, propolis, royal jelly, and bee venom that are playing increasing roles in health food and alternative medicine. Bee stings are routinely used for treatment of arthritis, multiple sclerosis and other auto-immune diseases.
* Honey bees are studied extensively, also because they are fascinating organisms. Bees have captured mankind's attention since as early as Aristotle. Not only because they produce honey and honey is the earliest sweetener human beings have found, but because of their industriousness (working to their death), selflessness (producing honey for humans and dying to defend their home), and most importantly, their social organization. Honey bees, like other social insects, show "division of labor" whereby different workers specialize on different tasks. In some sense, the complexity of their society rivals that of our own. Who governs their day-to-day chores? How do workers know what to do in a city bustling with tens of thousands of individuals? Clearly these have been the questions of humankind since long time ago, as evidenced in the Bible:
"Ants are creatures of little strength, yet they store up their food in the summer...Locusts have no king, yet they advance together in ranks." [Proverbs 30: 25-27].
* Honey bees are increasingly being used as a model system to study other aspects of biology. Besides their intricate social organization, honey bees are easily maintained, are cost effective in terms of obtaining large numbers of insects, and their genetics can be precisely controlled. Honey bee workers take 21 days to develop from eggs to adults, this compares favorably with other insects commonly used in classrooms (such as cockroaches, grasshoppers). Since a queen can lay as many as 1,500 eggs a day, large numbers of bees can be obtained easily. Honey bees are probably the only insect that has "artificial insemination" technique successfully invented. This is used extensively both commercially and in research to speed up the selection process and to control the exact genetic makeup of a colony.