(2nd Place) Partial removal of Wolbachia increases phytopathogen acquisition and decreases fitness in Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae)

Wolbachia is a maternally inherited intracellular bacterium that infects a wide range of arthropods. Wolbachia can have a significant impact on host biology and development, often due to its effect on reproduction. We investigated Wolbachia infection in the Asian citrus psyllid, Diaphorina citri, which transmits Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening disease. D. citri are naturally infected with Wolbachia; therefore, investigation of Wolbachia-mediated effects on D. citri fitness and CLas transmission requires artificial removal of Wolbachia. We used doxycycline to remove Wolbachia from D. citri. Doxycycline treatment reduced Wolbachia infection by approximately 0.80-fold in male and female D. citri. However, the effects of doxycycline on Wolbachia infection in psyllids varied between generations of treated psyllids. Psyllids treated with doxycycline exhibited higher CLas acquisition as both adults and nymphs compared to negative controls. In addition, doxycycline-treated psyllids exhibited decreased fitness as measured by reduced egg and nymph production and adult emergence compared with Wolbachia-infected lines. Further research is needed to improve methods for artificial removal of Wolbachia from D. citri, which will facilitate the production of uninfected lines. Our results suggest that Wolbachia benefits D. citri by improving fitness and potentially competes with CLas by interfering with acquisition.