Reproductive performance of the European grapevine moth Lobesia botrana (Tortricidae) is adversely affected by warming scenario

Iltis, Corentin [UCL] Moreau, Jérôme [UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France] Pecharová, Karolina [UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France] Thiéry, Denis [UMR INRA 1065, Santé et Agroécologie du Vignoble, Institut des Sciences de la Vigne et du Vin, 71 Avenue Edouard Bourlaux, 33882, Villenave-d’Ornon, France] Louâpre, Philippe [UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, 21000, Dijon, France]

The European grapevine moth, Lobesia botrana (Denis and Schiffermüller), is an important grape pest worldwide. To forecast how this species might respond to climate change has emerged as one major challenge in recent viticultural research. Predictions about L. botrana population dynamics under global warming scenario are usually derived from physiologically based demographic models (PBDMs). Despite their ecological realism, PBDMs are based on physiological equations derived from constant, unrealistic thermal regimes, and they exclude the effects of temperature on male’s reproductive traits, which importantly mediates population dynamics in this species. Focused on Burgundy (a viticultural region of France), we compared the adult performance of L. botrana between the Current Fluctuating Regime (CFR) based on in situ meteorological data and the Future Fluctuating Regime (FFR) based on the outputs of climate models. Under controlled conditions complying to the scenario of local warming termed FFR, L. botrana individuals incurred reduced adult lifespan, while their body amounts of four major energetic components (proteins, lipids, glycogen, soluble carbohydrates) remained unchanged compared to individuals exposed to the CFR. Furthermore, each sex endured reproductive costs associated with local warming scenario: females incurred reduced mating success, and males bore decreased fertility (lower number of eupyrene sperms within spermatophore). Our results indicate that global warming should adversely impact the reproductive success of L. botrana and the local abundance of this pest. In terms of pest management, our findings might contribute to the increase in the ecological realism of PBDMs and improve the reliability of their predictions about the population dynamics of L. botrana.