Karyotype of the egg chromosomes of the wolf spider Hippasa holmerae Thorell (Araneae: Lycosidae)
1999
Bugayong, M.J.G. | Barrion, A.A. | Papag, R.B. (Philippines Univ. Los Banos, College, Laguna (Philippines). Inst.of Biological Sciences)
Egg masses of the wolf spider (Hippasa holmerae Thorell) were collected, fixed in Carnoy's solution and stained with Lacto-aceto-orcein. Distinct features of the different stages of mitosis were observed and described. Nuclear shape and dimensional changes were observed at the interphase and prophase stages wherein the nuclei were spheroidal and oval, respectively. Mean mitotic index was 76.69 percent. The most frequently encountered stage was prophase while the least observed was telophase. Karyotype analysis of premetaphase chromosomes revealed that the diploid chromosome number (2n) of H. holmerae was 26. Mean relative lengths of chromosomes ranged from 0.033 to 0.109. Based on the position of the centromeres, the chromosomes of H. holmerae were classified into three types: median, submedian and subterminal. Arm ratio was 0.200-0.926 and the centromeric index was 16.67-42.86. Despite the occasional asynchronous behavior of few chromosomes during anaphase, mitosis in the egg chromosomes of H. holmerae was generally normal and regular
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