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 store for nectar, honeydew, or water. Its capacity is around 50 to 60 milligrams of liquid, roughly half the body weight of a worker bee. Even during transport to the hive, enzymes from the head glands added to the nectar begin the first transformation of the nectar toward honey in the honey stomach.
Between the honey stomach and the midgut lies the proventriculus, a valve-like funnel. It acts as a filter that separates solid components such as pollen grains from the liquid food and passes these solids on to the midgut. At the same time it releases the liquid load in portions, so that only a small part reaches the midgut for the bee's own digestion, while most of it is kept for passing on in the hive. Studies by the State Institute of Apiculture in Hohenheim also show that the proventriculus can even filter fungal spores out of the honey stomach.
In practice, the small capacity of the honey stomach explains why a forager has to visit a great many flowers for a single full load and why a colony's nectar intake depends strongly on the number of foragers flying at the same time. A common mistake is to confuse the honey stomach with a real stomach, when in fact it is first and foremost a transport and transfer organ; actual digestion only takes place behind it, in the midgut.