Morphology of the gnathosoma of Acarapis woodi (Acari: Acarapidae)

Abstract

The cheliceral stylets oiAcarapis woodi (Rennie) were studied using scanning electron microscopy (SEM). Capable of independent motion, the styliform cheliceral digits are grooved medially along their entire length and can be brought tightly together forming a tube-like structure. In addition, an unpaired structure was observed fitted along the stylet groove in a manner similar to that described previously for Pyemotes tritici (Bruce et al. 1993). It is not apparent that this structure is retractable and it may or may not function in the feeding process. The unpaired structure is homologized with the labrum and, while the morphological similarities of the mouthparts of P. tritici and A woodi are obvious, it is unclear as to whether or not it functions in precisely the same way in both species.