Cytological studies on six species of spiders from Taiwan (Araneae: Theridiidae, Psechridae, Uloboridae, Oxyopidae, and Ctenidae)

An improved newly introduced air-dried method was to prepare spider chromosomes. Chromosomal data are reported for 6 species of 5 families of spiders from Taiwan. The number of diploid chromosomes (2n) in both male (male) and female (female), the number of autosomal bivalents and the univalent sex chromosomes (X's) in the Ist meiotic division (n(I)) in male, the number of chromosomes in the 2nd meiotic division (n(ll)) in male, and the type of sex-determining mechanism of each species were determined as follows: Octonoba spinosa (Uloboridae) 2n = 18 male /20 female, n(I) = 8 + X1X2, n(II) = 8 and 10, X1X2O type; Achaearanea tepidariorum (Theridiidae) n(I)= 10 + X1X2, X1X2O type; Psechrus sinensis (Psechridae) 2n = 24 male, n(I) = 11 + X(1)X(2)r n(II) = 11 and 13, X1X2O type; Oxyopes macilentus (Oxyopidae) 2n = 21 male/22 female, n(I) = 10 + X, n(II) = 10 and 11 in the Taipei population, and 2n = 23 male, n(I) = 11 + X, n(ll) = 11 and 12 in the Hualien population, both XO type; Oxyopes sertatus (Oxyopidae) 2n = 21 male /22 female, n (I)= 10 + X, n(ll) = 13 and 11, XO type; and Anahita fauna (Ctenidae) 2n= 29 male, n(I)= 13 + X1X2X3, n(ll)= 13 and 16, X1X2X3O type. The chromosome data of Octonoba spinosa, Psechrus sinensis, Oxyopes macilentus, and Anahita fauna are reported for the first time. In addition, chromosome data of the families Psechridae and Ctenidae represented by Psechrus sinensis and Anahita fauna, respectively, are also reported for the first time. Oxyopes macilentus is reported to exhibit chromosome polymorphism among populations, and the diploid chromosome number 2n = 23 with 11 pairs of autosomes in 1 male is reported for the first time among all species of Oxyopes studied.