CYTOGENETICS OF SOME HETEROPTERAN SPECIES FROM BAHIR DAR, NORTH-WEST ETHIOPIA

Estifanos, Tarekegn

dc.contributor.author	Estifanos, Tarekegn
dc.date.accessioned	2018-07-02T08:30:37Z
dc.date.available	2018-07-02T08:30:37Z
dc.date.issued	2018-06-22
dc.identifier.uri	http://hdl.handle.net/123456789/8797
dc.description.abstract	The suborder Heteroptera constitutes one of the most important insect groups because most species are plant feeders and damage many plants of economic importance. This paper reports some cytogenetic aspects carried on male of Ethiopian Heteroptran species collected in different localities of Bahir Dar by hand picking. The material included three species from the family Pentatomidae, that is Eurydema pulchrum,Trimaculatus punctulatus,Euschistus servus,and one species from the family Coreidae, Cletus pallescens. The karyotype and meiosis in males of the species were studied using standard and with carbol-fuchsin stain for two to three hours. All species belonging to Pentatomidae, possess 2n=14=12A+XY while Cletus pallescens belonging to Coreidae possesses 2n=18=14A+2m+X1X20. Most meiotic characteristics are common in the three species of Pentatomidae such as fusion of the X and Y to form a heteropycnotic body at diffuse stage, and their behavior at diakinesis. However, the species differ in the extent of decondensation of the autosomes during the diffused stage and the number of ring bivalents at diplotene/diakinesis. Eurydema pulchrum,Trimaculatus punctulatus,and Euschistus servus show 2, 5, 1 ring bivalents, respectively. In most of the pentatomidae species, metaphase I is characterized by a ring of autosomal bivalents in the centre of which lie the X and Y univalents, but in Eurydema pulchrum metaphase I is characterized by 6 axially oriented chromosomes forming a ring that includes 5 autosomal bivalents and the X chromosome, while the largest autosomal bivalent and the Y chromosome are inside the ring. And in Euschistus servus autosomal bivalents and sex chromosomes were not arranged in a proper ring pattern, one of the autosomal bivalent got out of the ring as X and Y univalents were not exactly at the center. In Pentatomidae, metaphase II is radial where autosomal univalents form a ring in the centre of which lies the end- to- end associated XY pseudo bivalent. The coreidae species Cletus pallescens possesses minute M- chromosomes that were absent in analyzed Pentatimidae in this report. No Y chromosome was seen, sex chromosomes were X1X2 which showed slight size difference, and remain fused throughout meiosis except for a brief metaphase I.	en_US
dc.language.iso	en	en_US
dc.subject	biology	en_US
dc.title	CYTOGENETICS OF SOME HETEROPTERAN SPECIES FROM BAHIR DAR, NORTH-WEST ETHIOPIA	en_US
dc.type	Thesis	en_US