Comparative Cytogenetic Study of Two Species of Flour Beetles Tribolium castaneum ( Herbst, 1797) Rust Flour Beetle and Tribolium confusum ( Duval, 1968) Confused Flour Beetle (Coleoptera ; Tenebrionidae)

Abstract

Comparative cytogenetic studies were carried out on males of two species of flour beetles, Rust flour beetle Tribolium castaneum and Confused flour beetle Tribolium confusum to investigate the karyotype. In these species, somatic chromosomes were arranged according to its  length except the sex chromosomes.  Results of this study showed that complete chromosomes karyotyping  (2n)  of      T.castaneum equaled to twenty chromosomes ( 2n=20, XY ) whereas (2n) T.confusum equaled eighteen chromosomes ( 2n= 18,XY). In the two species the sex   chromosome Y was the shortest chromosome and had length of average ± standard error in T.castaneum equaled to 1.500 ± 0.0  µm whereas in T.confusum equaled to 2.000± 0.0  µm.  Based on  chromosomal length measurement the chromosomes  of  T.confusum were longer than  chromosomes of T.castaneum . The form of chromosomes in these species were described as metacentric chromosomes .