Comparative evaluation of Drosophila melanogaster and Drosophila simulans larva against environmental chemicals

ABSTRACT Background: Drosophila genus comprises of ~1600 species but predictable to have several thousands in number. D. melanogaster (DMG) Meigen and D. simulans (DSI) are also closely related to each other but morphologically have difference to each other. Both are cosmopolitan flies that are mostly found in the India and south-east Asian regions and resident in ours surrounding and eat to ripened fruits. Methodology: As compared to DSI, DMG is consideration to be progression modified to decaying, overripe and fermented fruits that released huge quantity of ethanol (EtOH), acetic-acid (AA), methanol (MeOH) and ethyl-acetate (EtOAc) chemicals. We explored the survival rate of DMG and DSI larva at various concentrations (ranging from 2-10%) of EtOH, AA, MeOH and EtOAc while inhibitory concentration 50 (IC50) was calculated and compare tolerance power and susceptibility of both against these chemicals.   Results: Firstly, a statistically significant (p>0.01) differences was observed between survival rate of DMG and DSI larva against 10% of EtOH (37.4 vs. 25.1%), AA (34.9 vs. 23.2%), MeOH (32.5 vs. 19.9%) and EtOAc (26.9 vs. 17.6%), respectively. Secondly, IC50 values of both larva of flies were found statistically significant (p>0.01) at 10% EtOH (DMG: 5.8-6.8 vs. DSI: 3.9-5.0%) and EtOAc (DMG: 3.8-4.8 vs. DSI: 2.3-3.6%). Thus we found a descending order of IC50 values as: EtOH>AA>MeOH>EtOAc for both flies. While survival rate and sensitivity order was found same but mortality and resistivity order (i.e. EtOAc>MeOH>AA>EtOH) are reciprocal to survival rate and sensitivity. Conclusion: To considering DMG and DSI larva’s have diverse habitats, ecological, physiological differences but DMG larva might exhibit higher susceptibility toward non-toxic chemicals released from fermenting and decaying fruits as compared to DSI larva. Hence, we found that DMG larva is more susceptible, tolerable against EtOH, AA, MeOH and EtOAc chemicals than larva of DSI.