How can Dermanyssus gallinae (De Geer 1778) (Acari: Anactinotrichida: Dermanyssidae) walk upwards on slippery surfaces?

How can Dermanyssus gallinae (De Geer 1778) (Acari: Anactinotrichida: Dermanyssidae) walk upwards on slippery surfaces? Avian Pathol. 2019 Apr 23;:1-25 Authors: Di Palma A, Mul MF Abstract Scanning electron microscopy observations of the distal leg region of the poultry red mite Dermanyssus gallinae (De Geer 1778) identified the presence of a compound ambulacrum, the part of the leg that contacts the substratum when the mite walks. The ambulacrum is comprised of a praetarsus (the ambulacrum stalk), a pulvillus and two claws. The pulvillus is a weakly sclerotized structure that can be partly expanded or retracted in the praetarsus. When expanded the pulvillus shows a cushion-like shape which can, as a result of its soft surface, function as a sucker, thus allowing D. gallinae to adhere to a smooth surface. When traversing an irregular surface, or clinging to a soft surface, the mite retracts the pulvillus and uses only it's strongly sclerotized movable claws. These observed morphological adaptations explain the ability of D. gallinae to climb upwards on a slippery surface, resist an air flux, walk on smooth and rigid feathers of its avian hosts, and cling to the bird's or human soft skin. This knowledge is important to better understand the attachment mechanism of this species to its host and to the substratum on which it moves, and also to provide insight into the circumstances under which it is able to move. PMID: 31012743 [...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research