Sex chromosomes of salticid spider Plexippus paykuhlii

The spermatogenetic studies of Plexippus paykuhli was carried out from 13 adults from three habitats of the campus of D M College of Science, with hypotonic fixative treatments and 4% Giemsa staining. The chromosomes number in pachytene stage was confirmed to be 28 and sex determination mechanism was X₁X₂0 type. Each gamete received 15 or 13 chromosomes and distribution seem to be disturbed in latter stage of the meiosis. During early stages of interphase, the two X chromosomes started as two dots and after S phase they became as larger, irregular, heteropycnotic body inside the nucleus. The dots were nearly jointed together and could be seen jointed till early pachytene probably at the centromeric regions. From the pachytene stage onwards close association could be seen till the metaphase I stage. The two X chromosomes were heteropycnotic throughout the meiosis I and late replicating. These were fairly joined together at the centromeric region till the early pachytene stage but seem to separate out during the later stages.