Experiments on the elimination of symbionts from the tsetse fly,Glossina morsitans morsitans (Diptera: Glossinidae), by antibiotics and lysozyme

One sulfonamide and ten antibiotics were tested for symbiont elimination in Glossina morsitans morsitans. Only tetracycline, penicillin, and kanamycin could be used in concentrations which destroyed the symbionts and impeded host reproduction, but did not affect host longevity. The later the treatment with penicillin and kanamycin began, the smaller was the damage to symbionts from these two antibiotics. Small doses damaged the symbionts to an extent that flies could produce offspring, but these were free of symbionts. Lysozyme was used as an alternative to antibiotics. After both injection and oral administration of lysozyme the symbionts were damaged, and host reproduction ceased, although host longevity remained unaffected. It can be concluded from the results of these experiments that tsetse flies do not require their symbionts for survival but probably do need them for reproduction.