The cytological studies of spiders in Manipur is very limited and studies on this aspect is much needed for species exploration. The study was carried from four families from two districts of Manipur. The males were dissected in hypotonic solution and fixed on the slides and stained in 4% Giemsa stain by keeping the slides in solution in a couplin jar. Identity of family Salticidae was Plexipus paykuhlii from the morphological aspects while the other three could identified upto generic level but not be identified upto the species level due to complexities and much variation in morphological characteristics so they were put up to the generic level. The diploid count of the four families were same with 28. The chromosomes number in pachytene/diplotene stage was confirmed to be 28 and sex determination mechanism in four families was X1 X2 0 type while it seems to X0 in Oxyopes. There were not many variations in the stages of the stages of the meiosis among the four families. The sex gametes were like flattened top: Plexipus and Pardosa had pointed end (Pardosa had much pointed ends) while the Oxyopes and Philodromus had blunt ends. These differences might be differences in collection stages of the division. There was little variation in the Meiotic stages in four families of the spiders. The main differences were on the deposition of the heterochromatins. The heterochromatins were much in each chromosome starting from Oxyopes, Pardosa and Philodromus sp. than the Plexippus. The significance difference was most prominent in the zygotene stages, the chromomeres were darkly stains in Oxyopes, Pardosa and Philodromus while the Plexipus was less darkly stained. Again, the separation of X chromosomes was also significant observation, they were positively heteropycnotic behavior and seem to be separated at zygotene only in Philodromus while remain associated in Plexipus, Pardosa and Oxyopes. On the basis of identical chromosome diploid count of 28 (except 21 in Oxyopes sp with single X): 26 acrocentric somatic chromosomes, X1X2 allosomes and absence of distinct chromosomal behavior during the meiotic cycle, only evolutionary significant point to focus here is the role of the heterochromatin. On the basis of the heterochromatin deposition Salticidae is the primitive family then Philodromus, Lycosidae as the advance family. In future, this minimum karyological diversity in the families, their cytological studies are seeming to best resolved using molecular cytogenetic studies as well as molecular methods involving the DNA sequencing and species identification and delineation of the positive species identification and importance of the cytological data on speciation in the four families.
Rajkumar Tombisana Singh, Moirangthem Bhubaneshwari Devi, Akham Kananbala Devi, Dhananjoy Singh Chingangbam. Comparative cytology of four families of spiders from two districts of Manipur, India. J Entomol Zool Stud 2020;8(1):46-54.