Correlation between toluene exposure of Drosophila melanogaster adults and toxicity effects on larval morphology

Toluene is a volatile organic compound found in common household products and in industrial settings. According to toluene's toxicological profile from the U.S. Department of Health and Human Services, chronic toluene exposure correlates to neurological defects, irregular fetal development, and hormonal changes in humans. Recent studies have shown that toluene exposure increases oxidative stress markers while other xenobiotics negatively affect larval development and fly emergence, as well as delay pupation in Drosophila melanogaster.  We hypothesize that toluene, when exposed to adult flies, affects the morphology, growth, development, and mortality of larval offspring.  To study these effects, we developed a continuous-flow system to deliver known concentrations of gaseous toluene to populations of D. melanogaster. From our current data, we extrapolated that the lethal concentration of toluene that kills 50% of the test population of flies (LC₅₀) is 264 ppm.  To observe effects of toluene on fly offspring, female flies exposed to toluene at the LC₅₀ were mated with unexposed male flies. Second instar larvae were collected at day three. Using light and scanning electron microscopy, larval morphology was examined.  Developmental differences in larval morphology were compared to the morphology of larvae from unexposed females and to known anatomical mutations.