Predicting the Potential Geographic Distributions of Two Large Predatory Insects, Microstylum dux and M. oberthurii (Diptera: Asilidae), Under Climate Change: A Comprehensive Analysis Based on Optimised Biomod2 Ensemble Model

Climate change profoundly impacts insect distribution and ecological functions. For the predatory robber flies Microstylum dux and M. oberthurii (Diptera: Asilidae), clarifying their distribution and climatic responses is vital for natural enemy conservation and biological control. Using a parameter-optimized biomod2 ensemble model, we predicted their potential distributions under current and future climates, and analyzed key variables, centroid shifts, and niche dynamics. Current suitable habitats concentrate in southeast China and are scarce in the northwest. Future total suitable area remains stable but structurally reorganizes, with highly suitable habitats expanding and moderately suitable ones contracting. Key drivers are precipitation of the coldest quarter (bio19) and mean diurnal range (bio2). Habitat centroids migrate westward or southwestward with fluctuating range expansion. M. dux is a niche specialist (niche width = 0.257), while M. oberthurii is a generalist (niche width = 0.539). Their niche overlap shows non-linear “divergence-convergence-divergence” dynamics. This study supports natural enemy conservation and biological control strategy formulation.