Wolbachia is one of the most common endosymbionts best known to induce several reproductive alterations in its insect hosts. In some cases, the insect hosts harbor more than two strains of the bacterium. The Vollenhovia emeryi ant lives in dead trees and is morphologically subdivided into the long-winged and the short-winged. Interestingly the short-winged morph is free of Wolbachia, but only the long-winged morph is multiple- infected with the Wolbachia bacterium. We sampled four populations of the long-winged morph in Korea and performed pyrosequencing in Multilocus Sequence Typing (MLST), to determine the bacterial strain diversity. Six different gene regions (coxA, fbpA, ftsZ, gatB, hcpA and wsp gene) were targeted and amplified. However, the result shows that diversity of haplotypes is very high. The pyrosequencing approach in MLST, a new method of discriminating Wolbachia strains, is promising to effectively detect multiple infections and rare haplotypes.

The hologenome theory of evolution proposes that an organism is simply not an individual but the totality of numerous microbial symbionts to the host. In fact, the evidence of biochemical and physiological associations between the symbionts and the host has been growing fast in all major taxa. The Vollenhovia emeryi ant is tiny and found nationwide in Korea. The ant can be further categorized by its wing morphology, eg. long-winged and short-winged. Our initial screening process showed that the microbial reproductive manipulator, the Wolbachia bacterium, only infected the long-winged morph. This gave us a good opportunity to investigate the effect of the Wolbachia infection on the bacterial community diversity using the next generation sequencing technique. We find that there are about 180 bacterial symbionts in the short-winged morph. On the other hand, the long-winged morph has only about 20 bacterial symbionts. This implies that the bacterial community diversity may be subject to the existence of Wolbachia. Furthermore, the Wolbachia strain diversity is unexpectedly high. In addition, the bacterial structure difference among castes indicates that there may be labour division even between queens. The results and future research direction will be discussed from the hologenome theory perspective.