Polymorphism among anterior and posterior sets of teeth in the periphallic organ of three species of Drosophila

For the first time, morphological polymorphism among the anterior and posterior sets of primary teeth of the periphallic organ was observed among natural populations of Drosophila. Natural and laboratory populations of 3 different species (D. ananassae, D. bipectinata, and D. malerkotliana) belonging to the ananassae subgroup were used to study the intra- and interspecific variations in the number of teeth of the anterior and posterior sets of the periphallic organ. There are about 22, 20, and 20 possible combinations of sets of teeth recorded in D. ananassae, D. bipectinata, and D. malerkotliana, respectively. The maximum frequency of anterior and posterior sets of teeth was found to be (5, 3) in D. ananassae and (2, 3) in the case of D. bipectinata and D. malerkotliana. The percentage of perfect bilateral symmetry was lower than that of asymmetry in all 3 species. A significant difference was found in anterior and posterior sets of teeth between different populations. These results indicate that the primary teeth of the anterior and posterior sets of the periphallic organ in Drosophila exhibit morphological polymorphism.