**6. The action machinery: salivary gland**

A successful feeding event of mosquitoes is regulated by the synchronized action of mosquito navigation and food choice decision which finally tuned

with the salivary gland action for successful food uptake. The endocrine system of the salivary gland induces saliva secretion that gets mixed with foods and facilitates the food intake [85]. Mosquitoes have paired salivary glands in their thorax which is flanking in the esophagus. During sugar feeding saliva is mixed with the sugar, and the mixture enters into the crop where digestion commenced. During blood meal ingestion, salivary gland secretions serve in blood vessel localization [86]. The hemostatic and immune factor of the vertebrate host makes the blood meal uptake process challenging for mosquitoes [86]. Thus, salivary glands of mosquitoes are evolved and adapted with a unique ability to serve the leading function during blood meal ingestion by providing secretory salivary factors such as vasodilators, anticoagulant, antihistamines, etc. [86, 87]. Furthermore, salivary gland components not only support mosquitoes to overcome host homeostasis and defense response but also serve as the primary route for parasite transmission and maintenance of disease cycle [86, 88]. Due to the involvement of salivary gland in malaria transmission, most of the previous studies are restricted to the role of salivary gland in blood feeding and pathogen survival [89]. A recent study by Sharma et al. showed that salivary gland has a distinguished ability of gene expression switching to manage the meal-specific (sugar vs. blood meal) molecular responses [90]. But, our understanding of the regulatory mechanism of the neuro-olfactory system modulating salivary gland cocktail composition depending on the type of food is still in infancy.
