Cytogenetics of three parthenogenetic Psocid species (Psocoptera, Psocomorpha)

A novel method was applied to study chromosomes and their behavior in female meiosis in three parthenogenetic psocid species (Psocoptera). Two of these species Valenzuela flavidus (Steph.). Caeciliusidae and Peripsocus subfasciatus (Rambur), Peripsocidae displayed a triploid chromosome number 3x = 27 while the third species Trichadenotecnum majus (Kolbe) was diploid (2n = 18). In all species meiosis consisted of only a single, mitosis-like maturation division, i.e. meiosis was of apomictic type. Models for the formation of polyploid parthenogenetic forms are discussed.