Thermogenesis-derived spatiotemporal microclimates guide pollinator movement to ensure pollination

Thermogenesis represents one of the oldest pollination traits; yet, the ecological function of the microclimates that it creates remains poorly understood. Here, we elucidate how the spatiotemporally dynamic microclimate of Alocasia odora orchestrates pollinator movement within its inflorescence. Upregulation of alternative oxidase (AOX) in the upper spadix generates a steep, diurnally fluctuating thermal gradient against the non-thermogenic lower chamber, forming a "thermal map". We demonstrate that this thermal push-pull mechanism, interacting synergistically with the insects' innate requirements, drives the cyclical vertical movements of its specialized Colocasiomyia pollinators. While strict feeding requirements establish a baseline preference for the lower sterile zone, species-specific oviposition preferences dictate their distinct movement trajectories. Specifically, C. xenalocasiae primarily drives pollen importation, whereas C. alocasiae acts as the dominant contributor to pollen exportation. In contrast, floral scent primarily functions in long-distance pollinator attraction, while light plays only a minor modulatory role in this fine-scale within-inflorescence navigation. Our comparative analysis reveals a prevalent spatiotemporal separation of sexual organs across thermogenic flowers globally. We therefore propose that microclimate-guided pollinator movement-where thermal gradients overcome structural constraints to ensure reproductive success-constitutes a widespread, yet underappreciated evolutionary strategy.