When a bee collects sugar-rich nectar, it sucks it out using a trumpet (a tube inside which is a mobile, flexible tongue) and places it in a storage sack (crop), which is separated from the honey stomach by a foregut, known as a valve.

The crop of a typical honey bee contains about 40 mg of nectar, or about 50 percent of the bee’s unencumbered weight (this may require visiting about a thousand flowers), The function of the foregut is to regulate the flow of pollen and nectar into the stomach. This allows the bee to take food from the crop when it has a long journey back to the hive and is running out of energy.