Genetically engineered (GE) rice lines expressing Lepidoptera-active insecticidal cry genes from
the bacterium Bacillus thuringiensis (Bt) have been developed in China. Field surveys indicated
that Bt rice harbours fewer rice planthoppers than non-Bt rice although planthoppers are not
sensitive to the produced Bt Cry proteins. The mechanisms underlying this phenomenon remain
unknown. Here, we show that the low numbers of planthoppers on Bt rice are associated with
reduced caterpillar damage. In laboratory and field-cage experiments, the rice planthopper
Nilapavata lugens had no feeding preference for undamaged Bt or non-Bt plants but exhibited a
strong preference for caterpillar-damaged plants whether Bt or non-Bt. Under open-field
conditions, rice planthoppers were more abundant on caterpillar-damaged non-Bt rice than on
neighbouring healthy Bt rice. GC–MS analyses showed that caterpillar damage induced the
release of rice plant volatiles known to be attractive to planthoppers, and metabolome analyses
revealed increased amino acid contents and reduced sterol contents known to benefit
planthopper development. That Lepidoptera-resistant Bt rice is less attractive to this important
nontarget pest in the field is therefore a first example of ecological resistance of Bt plants to
nontarget pests. Our findings suggest that non-Bt rice refuges established for delaying the
development of Bt resistance may also act as a trap crop for N. lugens and possibly other
planthoppers.