| Abstract: | Mitotic and meiotic chromosomes of four species of Anthonomus were analyzed. The meioformulas and diploid chromosome numbers observed were: 20AA + X[1]X[2]y[p], 2n = 43 (A. grandis and A. hunteri); 18AA + X[1]X[2]y[p] , 2n = 39 (A. fulvus); and 14AA + X[1]X[2]y[p], 2n = 31 (A. eugenii). This is the first report of an established multiple sex chromosome system with exclusive sex lumen association in Coleoptera. In order to confirm and further explore the existence of host-plant related polymorphism in chromosome number in the A. grandis species-group, sixteen populations of A. grandis and one population of A. hunteri were examined. A single meiotic karyotype was detected: 20AA + X[1]X[2]y[p]. The earlier observation of different chromosome numbers in this species-group could have been the result of misinterpretation of the sex chromosome system. Analyses of chromosome relative length and morphology of spermatogonial metaphases failed to reveal significant karyotypic differences between the populations studied. The potential of C-banding to study karyotypic polymorphism in Anthonomus was explored. Complex C-banded patterns with centromeric, interstitial, and telomeric bands were obtained in A. grandis. C-banding may be a useful tool to study karyotypic evolution and phylogeny in Anthonomus. The potential of genome size as a taxonomic character to further differentiate forms of A. grandis was explored. Anthonomus fulvus and A. eugenii were also included in the analyses for comparison. Extensive inter- and intraspecific genome size variation was observed among the populations studied. Significant differences were found between sexes within populations. Although significant DNA content differences were found among A. grandis populations, they were not taxonomically informative... |
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