Alimentary Canal

A sucking pump in the head draws food, honey or nectar or pollen, from the mouth into the esophagus. The tube of the esophagus passes backwards through the neck and thorax to become the honey stomach of the alimentary canal. This honey stomach resembles the crop of other insects but is adapted to transport nectar or honey and to store these foods for later regurgitation or digestion. From the honey stomach food to be digested then enters the true stomach or midgut or ventriculus through a narrow muscular proventriculus that regulates entry of food into the stomach. Digestion and absorption occur in the midgut. Inside the stomach, a thin peritrophic membrane secretes a delicate filmy cylinder around the mass of food. From the wall of the stomach, digestive enzymes pass through this peritrophic membrane to digest the food. Later, the products of digestion pass back through the peritrophic membrane once more before traversing the stomach wall to enter the hemolymph. What remains of the meal then enters the intestine. The intestine is divided into a narrow anterior part that is coiled and a larger pear-shaped posterior intestine or rectum that opens to the outside through the anus. These latter structures serve to absorb water and to discharge wastes. Bees retain feces in the rectum until they are evacuated outside the hive. In an over-wintering bee confined inside a hive, the rectum may distend to fill a large proportion of the abdominal cavity.

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