dc.description.abstract |
This study was intended to investigate the chromosome number, sex mechanisms and
meiotic behavior of seven species of suborder Heteroptera collected from Bahir Dar at
different localities by hand picking and insect net. Live adult male specimens were
dissected under stereoscope microscope (B3040) in 0.67% saline solution and fixed in
freshly prepared Carnoy’s fixative. The slides were stained with carbol fuchsin, mounted
on a microscope and well spread stages were photographed. In the present study four
species of Pentatomidae, two species of Coreidae and one species of Reduviidae were
cytologenetically investigated. Out of the four Pentatomid species, a male diploid number
of 14=12A+XY was found in Rhacognathus punctatus and Halyomorpha annulicornis
while 16=14A+XY was observed in Podisus nigrispinus and Banasa dimidiata. Male
diploid number of Coridae was found to be 18=14A+2m+X1X2O in Cletus borealis and
17=16A+XO in Acanthocephala femorata, while male diploid number of Reduviidae was
22= 20A+XY in Androcluspictus. Microchromosomes were present in one species of
Coreidae (Cletus borealis) and absent in the second species of Coreidae, all Pentatomidae
and Reduviidae of this study. Cytogenetic observation of all the seven species is the first
in Ethiopia and those of Rhacognathus punctatus (Pentatomidae) and
Acanthocephalafemorata (Coreidae) was the first for the cytogenetic world. Certain
characteristics are common in the three species of Heteroptera such as fusion of the X
and Y to form a heteropycnotic body at diffuse stage, and their behaviour at diakinesis
and metaphase II. Sex chromosomes, X1 and X2, remain fused throughout meiosis in
Cletus borealis.
Key words: Heteroptera, Pentatomidae, Meiosis, chromosomes |
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