Wolbachia enhances ovarian development in the rice planthopper Laodelphax striatellus through elevated energy production.

The endosymbiont Wolbachia can both benefit host nutrition and manipulate host reproduction to its own advantage. However, the mechanisms of its nutritional benefits remain unclear. We show that Wolbachia enhances ovarian development in the small brown planthopper Laodelphax striatellus by boosting energy production. Wolbachia-infected females have increased fecundity, accelerated ovarian development, and prolonged oviposition. Enhanced activity of mitochondrial complex I is linked to increased ATP production and the expression of energy metabolism-related genes. We further identify that Wolbachia-synthesized riboflavin is crucial for ATP production and ovarian development. A riboflavin transporter, slc52a3a, positively correlates with Wolbachia density and is required for normal ovarian maturation. Our findings demonstrate that Wolbachia-produced riboflavin drives energy production and accelerates ovarian maturation, thus improving host fecundity. This research reveals insights into symbiont-host metabolic interactions and underscores the role of nutrient delivery in symbiosis.