Wolbachia infections are distributed throughout insect somatic and germ line tissues

Wolbachia are intracellular microorganisms that form maternally-inherited i nfections within numerous arthropod species. These bacteria have drawn much attention, due in part to the reproductive alterations that they induce in their hosts including cytoplasmic incompatibility (CI), feminization and p arthenogenesis. Although Wolbachia's presence within insect reproductive ti ssues has been well described, relatively few studies have examined the ext ent to which Wolbachia infects other tissues. We have examined Wolbachia ti ssue tropism in a number of representative insect hosts by western blot, do t blot hybridization and diagnostic PCR. Results from these studies indicat e that Wolbachia are much more widely distributed in host tissues than prev iously appreciated. Furthermore, the distribution of Wolbachia in somatic t issues varied between different Wolbachia/host associations. Some associati ons showed Wolbachia disseminated throughout most tissues while others appe ared to be much more restricted, being predominantly limited to the reprodu ctive tissues. We discuss the relevance of these infection patterns to the evolution of Wolbachia/host symbioses and to potential applied uses of Wolb achia. (C) 1999 Elsevier Science Ltd. All rights reserved.