The honey bee’s digestive system can be said to begins with the pharynx; muscles used to suck liquid into the mouth. Two pair of salivary glands (the post-cerebral and thoracic) produce and excrete digestive enzymes into the mouth where they mix with nectar or water (henceforth referred to as liquid) which is then propelled through the esophagus. The esophagus passes from the head through the neck, called the cervicum, thorax, and waist, called the petiole and into the crop.
Also known as the honey stomach, the crop is an exceptionally distensible organ capable of holding up to 30 % of the bee’s weight in liquid. Located at the far end of the crop is a curious organ, the protoventriculus, which acts like a sieve of sorts; pushing itself into the interior of the crop it opens its shaggy 4-lipped mouth takes in liquid and then closing, filters out pollen grains. From this juncture the refined liquid passes into the ventriculus.
A coiled tube averaging about 2 times the length of the bee’s body, the ventriculus is lined with cells which produce digestive enzymes, and it is here that the bulk of digestion occurs. At its distal end, the ventriculus meets the small intestine, also called the ilium, about 100 malpighian tubules (tentacle-looking, kidney-like organs that absorb undigested material and nitrogenous waste) and segues into the small intestine. From the illium waste passes into the rectum, which like the crop is an elastic organ capable of expanding to occupy over half of the available abdominal space when need dictates.
Additionally, honey bees are thought to be able to absorb water from their excreta by means of rectal pads which allows them, during times of stress, to utilize this valuable resource without having to for example, break from the winter cluster.