2-Oxocarboxylic acid metabolic pathway fuels mitochondrial ATP synthesis to power oviposition in Bactrocera dorsalis

Abstract

For many insects, oviposition is an energy-intensive behaviour. However, the metabolic mechanisms powering this process are poorly understood for many species. Here, we investigated the link between energy metabolism and oviposition in Bactrocera dorsalis. The results showed that maturation of the ovipositor was accompanied by a significant increase in mitochondrial number. Transcriptomic analysis identified the 2-oxocarboxylic acid metabolic pathway as the most significantly up-regulated during development. Six core genes (citrate synthase [CS], aconitase [ACO], dehydrogenase 3 [IDH3]α, IDH3β, IDH3γ, glutamic-oxaloacetic transaminase 1 [GOT1]) within this pathway showed continuous expression increases, peaking at the oviposition stage, and were specifically enriched in ovaries and mature ovipositors. RNAi-mediated co-silencing of IDH3 subunits or individual knockdown of CS, ACO or GOT1 significantly reduced both egg deposition and ovipositor ATP levels, whereas individual IDH3 subunit knockdowns showed no significant effect. The ATP synthase inhibitor oligomycin A similarly induced a significant reduction in fecundity and disrupted ovipositor ATP homeostasis. Our study demonstrates that B. dorsalis oviposition is critically dependent on a tissue-specific 2-oxocarboxylic acid metabolic pathway that fuels mitochondrial ATP synthesis in the ovipositor. This establishes a direct functional link between core energy metabolism and reproductive behaviour, revealing novel potential targets for pest control.