Honey Stomach
Lexikon
The honey stomach is an expandable enlargement of the foregut in the bee's abdomen, located directly behind the wasp waist.
The honey stomach is an expandable enlargement of the foregut in the bee's abdomen, located directly behind the wasp waist. It serves as a transport and temporary storage vessel for nectar, honeydew, or water. Its capacity is around 50 to 60 milligrams of liquid, which corresponds to roughly half the body weight of a worker bee. Already during transport back to the hive, enzymes added from the head glands begin the first conversion of nectar toward honey inside the honey stomach.
Between the honey stomach and the midgut lies the proventriculus, also called the valve funnel. It acts as a filter that separates solid components such as pollen grains from the liquid food and channels these solids specifically into the midgut. At the same time it doses the liquid load in portions, so that only a small part reaches the midgut for the bee's own digestion, while the greater part remains reserved for passing on within the hive. Research from the Landesanstalt für Bienenkunde in Hohenheim also shows that the proventriculus can even filter fungal spores out of the honey stomach.
For practice, the small capacity of the honey stomach explains why a forager bee has to visit very many flowers for a single full load, and why a colony's nectar intake depends heavily on the number of foragers flying at the same time. A common mistake is confusing the honey stomach with a true stomach; in fact it is primarily a transport and hand-off organ, and actual digestion only takes place afterward, in the midgut.