ABSTRACT
Symbiosis is an intimate association between unrelated organisms, which has been essential in the evolutionary diversifi cation of eukaryotes (Moran and Yun 2015). Insects frequently share long-term and stable relationships with heritable bacteria which has enabled them to become the most diverse and successful animals on earth (Dale and Moran 2006, Brownlie and Johnson 2009, Gibson and Hunter 2009). Most bacterial symbionts in insects cannot be cultivated independently and they may be present in the low titer in the host (Oliver et al. 2010). The symbionts may be diffi cult to cultivate because of their slow growth, microaerophilic lifestyle, requirement for specifi c host metabolites and/or the loss and inactivation of genes, which reduces their independence (Pontes and Dale 2006).
