Tetracycline treatment influences mitochondrial metabolism and mtDNA density two generations after treatment in Drosophila

Tetracycline is commonly used to clear Wolbachia from infected insects. Studies then compare specific biochemical and/or life-history traits between infected and uninfected individuals with the same genetic background. We investigated the potential for tetracycline to influence mitochondrial efficiency and mitochondrial (mt)DNA density two generations after treatment in Drosophila simulans. We observed that antibiotic treatment resulted in a decline in inorganic phosphate incorporated into ATP per mole of oxygen consumed (ADP:O ratio). Further, tetracycline treatment caused a significant increase in mtDNA density in naturally Wolbachia-uninfected but not in naturally Wolbachia-infected lines suggesting a dosage effect. These data suggest that the current practice of comparing Wolbachia-infected and Wolbachia-uninfected insects two generations after tetracycline treatment needs to be re-evaluated.