Distribution and evolutionary impact of wolbachia on butterfly hosts.

Wolbachia are maternally inherited endosymbiotic alpha-proteobacteria found in terrestrial arthropods and filarial nematodes. They are transmitted vertically through host cytoplasm and alter host biology by inducing various reproductive alterations, like feminization, parthenogenesis, male killing (MK) and cytoplasmic incompatibility. In butterflies, some effects especially MK and sperm-egg incompatibility are well established. All these effects skew the sex ratio towards female and subsequently favor the vertical transmission of Wolbachia. Some of the insects are also infected with multiple Wolbachia strains which may results in some complex phenomenon. In the present review the potential of Wolbachia for promoting evolutionary changes in its hosts with emphasis on recent advances in interactions of butterfly-Wolbachia is discussed. In addition to this, strain diversity of Wolbachia and its effects on various butterfly hosts are also highlighted.