Wolbachia infection modifies phloem feeding behavior but not plant virus transmission by a hemipteran host.

Wolbachia-infected and uninfected subpopulations of beet leafhoppers, Circulifer tenellus (Baker) (Hemiptera: Cicadellidae), co-occur in the Columbia Basin region of Washington and Oregon. While facultative endosymbionts such as Hamiltonella defensa have demonstrably altered feeding/probing behavior in hemipteran hosts, the behavioral phenotypes conferred by Wolbachia to its insect hosts, including feeding/probing, are largely understudied. We studied the feeding/probing behavior of beet leafhoppers with and without Wolbachia using electropenetrography, along with corresponding inoculation rates of beet curly top virus, a phloem-limited plant pathogen vectored by beet leafhoppers. Insects carrying the virus with and without Wolbachia were individually recorded for four hours while interacting with a potato plant, and wavelengths annotated following established conventions. Virus inoculation rates and the duration of phloem salivation events did not vary. Wolbachia-infected insects more than tripled the duration of phloem ingestion, but despite this, Wolbachia infection was linked with marginally lower, not enhanced, acquisition. Regardless, results suggest potential for Wolbachia to increase the acquisition rate of other phloem-limited plant pathogens.