Honey bees are social insects that live in colonies.
A bee colony consists of a queen bee, male drones and thousands of female worker bees.
Each colony also contains eggs and immature bees in various stages of development.
The number of bees within a colony depends on seasonal changes.
A colony's population increases during the warm seasons and decreases during colder seasons.
In recent years, many bee colonies have collapsed or disappeared.
A bee colony collapse occurs when a majority of the bees in a colony disappear and leave behind the queen.
Some beekeepers have reported losing 30 to 90 percent of their colonies.
This loss of bee colonies can cause significant problems for farmers who depend on them to pollinate their crops.
In some parts of the world邻吭，a shortage of bees has increased the cost of renting bees by up to 20%.
There are several possible causes for bee colony collapse.
One possible cause is the use of new pesticides.
Other possible causes include infections from viruses, genetic factors, and malnutrition.
Changing weather patterns may also play a role as summers get hotter and winters get colder.
These changes in weather may weaken the bees, making it more difficult for them to fight infections.
Whatever the cause of colony collapse， it's important to understand that many parts of our world are interdependent.
Changes that affect one species may have serious effects on other species.
A change to our environment can start a chain of events that is difficult to predict.
In any complex system such as the Earth's environment, small changes can have unforeseen consequences.
The danger of unforeseen consequences is something we all need to understand better.
(The earth's environment is an extremely complex system.)
（In addition to making honey, honeybees help many plants reproduce.)
