Climate change can generate enemy‐free space for crop‐feeding herbivores

Crop-feeding herbivores reduce the world's food output by approximately 20% and climate change (CC) is bound to deepen those losses. Endemic or introduced consumer organisms (i.e., biological control agents) naturally regulate herbivore populations and secure a quarter of crop yields, but are exceptionally susceptible to CC-related disturbances. Here, we use niche modeling for 14 globally-important herbivores (or pests) to forecast how richness of the associated biological control agents of each pest—as a proxy of service strength—may alter under a CC-driven range expansion. Results show that 57%–100% of pests are bound to lose parasitoid and predator associates. The cassava mealybug Phenacoccus manihoti may experience a 27% decline in parasitoid pressure, whereas cosmopolitan pests of cereal and horticultural crops benefit from 6% to 7% drops in predator pressure. Such ‘enemy release’ can possibly exacerbate pest-induced yield losses and threaten future harvests. Ant-pest associations change in both directions, implying that pests may either face strengthened or weakened biological control. For pests spreading towards or within food-deficit regions in the equatorial belt, parasitoid declines and increases in ant pressure are most pronounced. By exposing the fragility of biodiversity-based ecological safeguards in farmland, our work calls for urgent, integrative, and nature-friendly solutions to uphold food security under environmental change.