Distribution and phenotypic effect of Wolbachia in natural population of Indian Drosophila

Abstract

Background & objectives: Wolbachia (alpha-proteobacteria, Rickettsiaceae) undergoes maternal transmission and manipulates host reproductive fitness. Wolbachia strains in the Drosophila host (wMel, wRi) have significant implications in controlling arboviral diseases and are being transfected into the mosquito population. The efficient use of Wolbachia as a biocontrol agent calls for a need to understand its biology and host-symbiont interactions. The present work is a baseline study to explore the distribution of Wolbachia strains and their effect on the reproductive fitness of Drosophila (Drosophilidae, Diptera) hosts from India. Methods: The distribution and strain identification of Wolbachia was done by PCR and sanger sequencing method in Indian Drosophila host species. For further setting up of host-phenotype experiments, control (nature-caught Wolbachia- infected) and treated (antibiotics-treated Wolbachia-uninfected) host Drosophila laboratory-established lines were used. Results: The presence of Wolbachia was found to be limited to only three Drosophila host species i.e. D. melanogaster, D. simulans and D. ananassae and their distribution frequency was not influenced by host ecological background. Wolbachia infection was seen to provide a fitness advantage in terms of reproductive success in D. melanogaster; however, tetracycline treatment could not remove Wolbachia from D. ananassae, preventing us from conducting experiments in this species. Interpretation & conclusion: These results reaffirm the host specific nature of Wolbachia infection and highlight for the first time Wolbachia distribution and phenotypic effect in Indian Drosophila host. In the wake of world mosquito programme, it is crucial to identify Wolbachia strains in natural population and evaluate their effects on host species for making it an effective bio-control agent.