Karyological investigations on five species of Rutelinae (Coleoptera: Scarabaeidae)

Karyological investigations were carried out on adult male individuals of five species of pleurostict scarabaeoid beetles, viz, Mimela glabra Hope, Anomala bengalensis Blanch., Rhinyptia indica Burm., Adoretus bombinator Burm. and A. epipleuralis Arrow. The first three species exhibited the ‘modal’ polyphagan karyotype 2n = 20:9 + Xyp, whereas the Adoretus spp. exhibited 2n = 22: 10 + Xy, karyotype. All the species are characterized by the possession of biarmed chromosomes. The autosomes showed a gradual decrease in size. The X chromosome was next in size to the last pair of autosomes. It was smallest (2.10μ) in Mimela glabra. The y chromosome had appreciable size but was always the smallest element of the karyotype. However, in Anomala bengalensis, the X and y were almost equal sized (4.38 p and 4.28 p). The mean chiasma frequency per nucleus was 12.0, 13.0 and 13.0 in Mimela glabra and Adoretus spp., quite high by scarab standards.