ABSTRACT
Inherited symbionts play an important role in the ecology and evolution of many species. One such inherited symbiont, Wolbachia, is known to have many interesting and diverse symbiotic associations with its arthropod and nematode hosts, ranging from parasitism to mutualism (Werren et al. 2008). The organism is notable for signifi cantly altering the reproductive capabilities of its arthropod hosts and manipulating their cell biology by inducing different phenotypes such as male killing, feminization, parthenogenesis, cytoplasmic incompatibility (sperm–egg incompatibility) and even speciation in certain species (Werren et al. 2008). These interactions become more interesting due to the spatial variation and phenotype of Wolbachia strains. Wolbachia strains that are genotypically very closely related can induce diverse phenotypic effects in different hosts, whereas different strains can induce similar phenotypic effects in the same hosts (Jiggins et al. 2002). Therefore, characterization of the Wolbachia genotype and its phenotypic effect in different hosts is important for understanding the ecology and evolution of different species. Since Wolbachia cannot be cultured outside host cells, traditional microbiological methods cannot be applied to study these bacteria. Currently, they are categorized into eleven different ‘supergroups’ (labelled alphabetically A–K) on the basis of clades formed in gene phylogenies (Lo et al. 2002; Bordenstein and Rosengaus 2005; Casiraghi et al. 2005; Ros et al. 2009). Termites are a group of social insects usually classifi ed in the taxonomic rank of order Isoptera, and described as ‘ecosystem engineers’ due to their important role in providing soil ecosystem services. They are major detrivores, particularly in the subtropical and tropical regions, and their recycling of wood and other plant matter is of considerable ecological importance (Harris 1971). Their ancient origin (Devonian period), great diversity and considerable ecological, biological and behavioural plasticity suggests that characterization of Wolbachia in this group is needed in order to understand the impact of the symbiont on termite reproduction, evolution and speciation (Roy and Harry 2007). The phenotypic effects of Wolbachia in Isoptera are still unknown but molecular data concerning these termite symbionts have recently become available. The available literature suggests the occurrence of Wolbachia in termite families Termopsidae, Kalotermitidae, Serritermitidae, Rhinotermitidae and Termitidae. Four phylogenetically different Wolbachia supergroups have been reported in termites. Twenty termite species have been reported to harbour Wolbachia. Out of these, thirteen species (Kalotermes fl avicollis, Coptotermes lacteus, Coptotermes acinaciformis, Cryptotermes secundus, Heterotermes sp., Nasutitermes takasagoensis, Nasutitermes sp., Nasutitermes nigriceps, Hospitalitermes mediofl avus, Microcerotermes sp., Apilitermes longiceps, Labiotermes labralis, Microtermes sp.) have supergroup F Wolbachia infection (Casiraghi et al. 2005; Lo et al. 2002; Lo and Evans 2007; Roy and Harry 2007). Two Zootermopsis species (Zootermopsis nevadensis and Zootermopsis angusticollis) carry supergroup H Wolbachia (Bordenstein and Rosengaus 2005). Cubitermes sp. affi nis subarquatus harbour diverse types of Wolbachia belonging to the supergroup A and B clade (Roy and Harry 2007), Incisitermes snyderi carry supergroup A Wolbachia (Baldo et al. 2006), while Wolbachia from Serritermes serrifer, Neotermes luykxi and Neotermes jouteli belong to a divergent sister clade within supergroup A (Lo and Evans 2007). Termites, like other groups of arthropods, can tolerate Wolbachia of more than one supergroup, although individual species can harbour only single infections. This provides some evidence for the horizontal transmission of Wolbachia. Infection with different Wolbachia supergroups in various termite species can be parsimoniously explained by independent acquisition of these lineages in termites, rather than a single ancient ancestral infection, with subsequent divergence and/or widespread loss (Bordenstein and Rosengaus 2005).