Morphological, ultrastructural and functional adaptations of the mouthparts in cheyletid mites (Acari: Actinedida: Cheyletidae)

The cheyletid family includes more than 370 predatory and parasitic species. According to their feeding habit, some are involved in the integrated pest management of stored food, while other species are parasitic both of men and domestic animals. They all suck up liquid food after piercing tissues with their mouthparts showing peculiar adaptations to this feeding behavior. Like in other taxa of mites, the movable digits have been transformed into stylets that reach the tip of the gnathosoma, enclosed into the malapophyses and lateral lips, and enable the mite to pierce the animal tissues. Since the stylets are short, they serve merely for superficial penetration. Reduced fixed digits cover dorsally the infracapitulum and keep in place the stylets with a peculiar overlapping system. The cheliceral bases are proximally completely fused to each other but also fused with the infracapitulum, thus forming a “stylophore capsule.” Food intake is realized through the preoral groove and the food channel thanks to the pumping action of the pharyngeal chamber. Feeding activity is regulated by several sense organs. A three-dimensional reconstruction is provided with dynamic evidences of the functioning.