DIVERSITY IN EXTERNAL MORPHOLOGY, SEX COMB AND DEVELOPMENTAL STAGES OF THREE DROSOPHILA SPECIES OF MELANOGASTER GROUP

Abstract

Samples of Drosophila species were collected from some selected sites (viz.,
Dohar Upazila of Dhaka Division, Hironpoint of the Sundarbans, Satchori of
Sylhet Division) of Bangladesh and these were cultured in the laboratory to
study developmental stages, external morphological traits and sex comb. They
were identified as D. melanogaster, D. ananassae and D. bipectinata. The sex comb
teeth number and arrangement were distinct for all three species. D. melanogaster
had one row of 10 - 11 teeth in the sex comb. D. ananassae had eight rows of teeth
in the sex comb possessing 32 - 33 teeth in total. D. bipectinata had 2 - 3 rows of
teeth in the sex comb and total teeth number varied from 11 to 15. Among three
species, sex comb teeth number of D. bipectinata varied most. Eleven different
patterns (n=20) in sex comb were observed in D. bipectinata indicating significant
diversity within species. Variation in pupation sites among three species was also
observed in the laboratory condition. D. bipectinata pupated on the food medium,
whereas other two species pupated on the vial wall. Thus, diversity among these
three species of Drosophila was documented which could be utilized as bioindicator
in future.