Cytogenetics of Mites and Ticks

There are three reviews of the cytogenetics of certain mites and ticks (43, 48, 75). The number of acarines studied cytologically more than doubled during the lO years between Sokolov's review and Oliver's first review. The number has now doubled again. Even with this increase in information our knowledge of the cytogenetics of acarines is still fragmentary. Over 30,000 species and 1700 genera have been de­ scribed and it is believed that a half million more species are extant (35). Neverthe­ less, data from our small cytogenetic sample indicate that an enormous amount of cytological and genetic diversity exists among mites and ticks. Somatic chromosome numbers range from 2 to 36, various sex chromosome systems are operative, and different kinds of chromosomes and reproductive mechanisms exist. The purpose of this review is to consider some of the fascinating aspects of the cytogenetics of mites and ticks by examining karyotypes, sex determination, and chromosome types.