The genetic basis of host plant adaptation in the brown planthopper (Nilaparvata lugens)

We studied the genetic architecture of host plant adaptation in two populations of brown planthopper Nilaparvata lugens (Homoptera: Delphacidae): one feeding on cultivated rice Oryza sativa and the other feeding on a weed grass Leersia hexandra. Proportional weight change, survival and development time of inbred Leersia- and rice-feeding lines, F(1), F(2), and backcross classes have been examined. Most of the performance differences among populations seem to be controlled by a few genes. Dominance of rice population alleles over Leersia population alleles was quite strong, and there was evidence for epistatic interaction. Nymph-to-adult survival of the cross classes was found to be highly correlated with mean weight change of the adults. These results are discussed in relation to a presumed host shift from Leersia to rice.