Olfactory conditioning improves the predation efficacy of the predatory mite Amblyseius largoensis

BACKGROUND: Olfactory conditioning, a key manifestation of behavioral plasticity, is known to enhance insect fitness in nature. It remains unclear, however, whether predatory mites-which share a common arthropod ancestry with insects but belong to a distinct evolutionary lineage-have a comparable capacity for olfactory conditioning. To bridge this knowledge gap, we assessed associative olfactory learning in the predatory mite Amblyseius largoensis by exposing it to herbivore-induced plant volatiles (HIPVs) from citrus plants infested with its prey, Panonychus citri. RESULTS: Trained mites showed preference shifts toward these herbivore-associated chemical signals, requiring less time to locate prey, consuming more prey individuals and producing more eggs than naive counterparts. Individual HIPV compounds (α-farnesene, humulene, linalool, β-ocimene, caryophyllene) each demonstrated unique training effectiveness, whereas cross-reactivity bioassays revealed hierarchical chemical information processing with both compound-specific and categorical responses. CONCLUSION: The success of olfactory training suggests that the mite chemosensory system provides reliability for ecological applications where consistent, robust conditioning responses are essential for predation effectiveness.