| A systematic investigation is needed to better define and understand the parameters regarding the veracity and utility of entomological evidence with regard to toxicology. The purpose of this study was two-fold. First, the effects of each drug on duration of the feeding larval stage of the black blow fly, Phormia regina, and the subsequent mass and length of their mature larvae were evaluated. Second, the deposition of the barbiturates and amphetamines based on the log P and pKa values were evaluated. In both prongs of the study, 7 drugs were investigated: sodium barbital, pennobarbital, sodium pentobarbital, sodium thiopental, ephedrine hydrochloride, methamphetamine hydrochloride, and fenfluramine hydrochloride. P. regina were wild trapped and maintained in a laboratory colony at a controlled temperature and light cycle. Larvae from the colony were reared on 3 concentrations of each drug and a drug free control. When the larvae began migration, they were harvested, cleaned, and frozen. Despite statistical differences in the average lengths of drug laden and drug free larvae within this study, the lengths fell within the natural variation for the species. The middle concentration of ephedrine and the high concentration of thiopental were exceptions to these data by causing larvae to grow significantly longer than the control and outside the natural variation for the fly and indicating larvae older than their measured life cycle. In order to evaluate the deposition of drugs into the larvae, a sample of larvae were homogenized, diluted, and subjected to liquid-liquid drug extraction. The extracted drugs were derivatized and analyzed by gas chromatography/mass spectrometry. Drug deposition results were analyzed by linear regression to find a correlation between whole larvae drug concentration and food source drug concentration. In the concentration ranges investigated, the concentrations of all of the drugs found in the larvae strongly correlated with the concentration of the drug in the food source. While barbiturate accumulation indicated drug deposition in relation to drug lipophilicity, the amphetamines did not accumulate or show any trends in deposition with regard to lipophilicity. |
