Wigglesworthia

Wigglesworthia is a genus of Gram-negative bacteria that form obligate intracellular endosymbionts of tsetse flies (Glossina spp.). The best known member, Wigglesworthia glossinidia, resides within specialized host cells called bacteriocytes inside a dedicated bacteriome and is vertically transmitted from mother to offspring, primarily via the milk produced by the female’s milk glands during larval development.

In the tsetse fly, Wigglesworthia provides essential nutrients that the host cannot obtain in sufficient quantities from its diet or metabolism, most notably B vitamins and cofactors. This nutritional provisioning supports larval development, adult fertility, and immune system function, making the symbiosis critical for host fitness. The relationship is highly host-specific and obligate; disruption of the symbiont reduces survivorship or fecundity.

Genomically, Wigglesworthia species show substantial genome reduction typical of long-term intracellular symbionts, retaining genes for vitamin biosynthesis and essential metabolism while losing many genes required for independent life. The symbiosis is tightly integrated with Glossina biology and shows co-evolution with tsetse lineages.

Ecologically and scientifically, Wigglesworthia serves as a model system for studying endosymbiosis, host nutrition, and insect–microbe interactions. It also informs approaches to affect tsetse biology and disease transmission indirectly through microbiome manipulation.