In response to insect attack, plants release complex blends of volatile compounds. These volatiles serve as foraging cues for herbivores, predators and parasitoids, leading to plant-mediated interactions within and between trophic levels. Hence, plant volatiles may be important determinants of insect community composition. To test this, we created rice lines that are impaired in the emission of two major signals, S-linalool and (E)-β-caryophyllene. We found that inducible S-linalool attracted predators and parasitoids as well as chewing herbivores, but repelled the rice brown planthopper Nilaparvata lugens, a major pest. The constitutively produced (E)-β-caryophyllene on the other hand attracted both parasitoids and planthoppers, resulting in an increased herbivore load. Thus, silencing either signal resulted in specific insect assemblages in the field, highlighting the importance of plant volatiles in determining insect community structures. Moreover, the results imply that the manipulation of volatile emissions in crops has great potential for the control of pest populations.

The rapid wide-scale spread of fall armyworm (Spodoptera frugiperda) has caused serious crop losses globally. However, differences in the genetic background of subpopulations and the mechanisms of rapid adaptation behind the invasion are still not well understood. Here we report the assembly of a 390.38-Mb chromosome-level genome of fall armyworm derived from south-central Africa using Pacific Bioscience (PacBio) and Hi-C sequencing technologies, with scaffold N50 of 12.9 Mb and containing 22,260 annotated protein-coding genes. Genome-wide resequencing of 103 samples and strain identification were conducted to reveal the genetic background of fall armyworm populations in China. Analysis of genes related to pesticide-and Bacillus thuringiensis (Bt) resistance showed that the risk of fall armyworm developing

Toxins from the bacterium Bacillus thuringiensis (Bt) are used widely for insect control in sprays and transgenic plants, but their efficacy is reduced when pests evolve resistance. Previous work showed that mutations in a gene encoding the transporter protein ABCC2 are linked with resistance to Bt toxins Cry1Ab, Cry1Ac or both in four species of Lepidoptera. Here we compared the ABCC2 gene of Helicoverpa armigera (HaABCC2) between susceptible strains and a laboratory-selected strain with >1,000-fold resistance to Cry1Ac relative its susceptible parent strain. We discovered a 73-base pair (bp) insertion in the cDNA of the resistant strain that generates a premature stop codon expected to yield a truncated ABCC2 protein. Sequencing of genomic DNA revealed that this insertion is an intron that is not spliced out because of a 6-bp deletion at its splicing site. Analysis of progeny from crosses revealed tight genetic linkage between HaABCC2 and resistance to Cry1Ac. These results provide the first evidence that mis-splicing of a gene encoding an ABCC2 protein confers resistance to a Bt toxin.