The honeybee's immune system is the principal barrier against diseases and pathogens. It is classified into social and individual immunity ⁴.

The social immunity is a collective behavior seen in Apis mellifera (Honeybee) and other social insects, and it has the objective to reduce the risk of disease outbreaks. Every bee in the colony does small tasks and altogether have a high impact against parasites and pathogens.4 Social immunity is divided into defensive behavior and environment modification. The defensive behavior includes the hygienic behavior as grooming themselves or to each other, exhaustive beehive cleaning of potential infectious elements such as residues or carcasses within the hive. Also, they clean up after the death (2). The environment modification consists of the collection of propolis (plant resins)5 and use them to create an antiviral and antimicrobial envelope for the beehive.⁴.

On the other hand, the individual immunity of honeybees has several lines of innate immune defense against pathogens. The chemical and physical barriers like the exoskeleton cuticle and the peritrophic membranes at the digestive tract are the first line of defense against pathogens. In the case of a breach of the physical and chemical barriers, there is a cellular and humoral response that constitute the second line of defense. The innate immunity of the bee is activated due to the recognition of the structural motifs on the pathogens' surface known as Pathogen-Associated Molecular Patterns by Pattern Recognition Receptors. The signal cascades could active the phagocytosis, coagulation or melanization of the hemolymph or the synthesis of antimicrobial peptides (AMPs) such as abaecin, apidaecin, defensin and hymenoptaecin.⁴.

The antimicrobial peptides are synthesized in the fat body of the honeybee as pro-peptides (inactive-form) and are cleaved (active-form) upon infection. These peptides have properties against bacteria, viruses, and fungi.⁵.

The mouth is the first part of the digestive system. It is in the anteroinferior part of the head and belongs to the licking-sucking classification. The queen, the drone and the worker bee present different structures.⁶

When Bees take liquid foods using the proboscis, which is formed by different pieces of the oral apparatus.⁶ The proboscis is not an organ as such, but it is a group of structures that unite and have a particular function. By this retractable structure is how it ingest and regurgitates, nectar, water or honey.⁷ Bellow is an image where the structure is retracted and when it is not.

When the proboscis is retracted, the tube is under the head; when the bee prepares to absorb liquids, it projects it forward, extending its distal parts around the tongue, in such a way that a tube is formed that closes in front of the distal end of the maxilla; in the back, the labial palps close.⁶

Unfolding the tube is introduced into the liquid, in quick movements back and forth the liquid rises. When the mandible and proboscis are contaminated, are the vehicle for an infestation of larvae by American foulbrood (Paenibacillus larvae) or European foulbrood (Melissococcus plutonius).⁶

The Esophagus is a tube that extends along the thorax, whereby food does it road thanks to its contraction movements, by muscle waves that move in an anteroposterior way.⁶

In the proximal end of the abdomen, the esophagus widens into a sack with thin and highly elastic walls, named the social stomach. When it is filled, their walls expand rhythmically causing their content mix. It is also used as food stock. The proventriculus is a narrow, muscular channel that controls the entry of food into the stomach (ventricle) of the bees, acting as a filter, eliminating the solids from the content of the social stomach. Its previous part is X-shaped. Through this valve, the bee can selectively remove the pollen from the nectar or honey and pass it to the ventricle. Below is an illustration of this valve.^6,7