ESTERASE ISOENZYME ANALYSIS OF 4 ONTOGENIC STAGES OF DROSOPHILA-MELANOGASTER POPULATIONS SELECTED FOR FAST AND SLOW DEVELOPMENTAL TIME AND TREATED WITH VERTEBRATE AND PLANT STEROIDS

Drosophila melanogaster populations selected for 27 years for fast and slow developmental rate were treated with steroid hormones (ecdysone, vitamin D3 and Solanum malacoxylon (Solanacea, Tubiflorae) vitamin D3 -glycoside) to determine their effect on the esterase patterns of four ontogenetic stages (end of third larval instar, early pupae, pharate pupae and imagoes). Vitamin D3 promoted the greatest difference in est erase activity pattern. The effect of S, malacoxylon glycoside was mos t similar to that of ecdysone in the fast population and most similar to that of vitamin D3 in the slow population. When the similarity inde x was used to compare populations it was found that the S. malacoxylon treatment was the most effective in promoting differences in the este rase pattern between fast and control populations and the vitamin D3 t reatment was the most effective in enhancing the difference between th e fast and slow populations. In the comparison between slow and contro l populations, except for vitamin D3, all treatments including the unt reated sample showed similar degrees of difference. Plant steroids dif fer from vertebrate hormone by an additional glycoside. Their effects on D. melanogaster metabolism differed and were dependent on endogenou s hormonal content of the selected populations, which were previously found to be different (Jung, 1992).