Divergence of the regulation of α-amylase activity in Drosophila melanogaster, Drosophila funebris, and Drosophila saltans

The regulation of amylase activity in three Drosophila species, D, melanogaster, D. funebris and D. saltans, was analyzed by measuring the specific activity levels in four dietary environments, cornmeal, glucose, 5% starch, and 10% starch, at three developmental stages, i.e., the third-instar larval, pupal, and 2-day-old adult stages. The developmental profiles of amylase activity for the three Drosophila species showed that the level of activity tvas high at the larval and adult stages but substantially low at the pupal stage, sugggesting that Drosophila does not utilize starch at the pupal stage. Divergence in the regulation of amylase was observed among the three Drosophila species on the following points. (1) The order of amylase specific activity was D. melanogaster > D, funebris > D. saltans. (2) The response pattern to the dietary environment varied among the species and changed during development. (3) The timing of the switch in the response pattern ro the dietary environment-during development was before pupation in D, funebris and D, saltans bur after pupation in D, melanogaster. The significance of the divergence in the regulation of amylase activity for adaptation to a starch environment in Drosophila is discussed.