The oriental armyworm genome yields insights into the long-distance migration of noctuid moths

The oriental armyworm, Mythimna separata, is known for its long-distance seasonal migration and environ-ment-dependent phase polymorphisms. Here, we present a chromosome-level genome reference and integrate multi-omics, functional genetics, and behavioral assays to explore the genetic bases of the hallmark traits of M. separata migration. Gene family comparisons show expansion of gustatory receptor genes in this cereal crop pest. Functional investigation of magnetoreception-related genes and associated flight behav-iors suggest that M. separata may use the geomagnetic field to guide orientation in its nocturnal flight. Comparative transcriptome characterizes a suite of genes that may confer the observed plasticity between phases, including genes involved in protein processing, hormone regulation, and dopamine metabolism. We further report molecular signatures that underlie the dynamic regulation of a migratory syndrome coordi-nating reproduction and flight. Our study yields insights into environment-dependent developmental plas-ticity in moths and advances our understanding of long-distance migration in nocturnal insect pests.

Automated summary

In this study, we present a chromosome-level genome reference of the oriental armyworm and explore the genetic bases of its migration traits using multi-omics, functional genetics, and behavioral assays. We found an expansion of gustatory receptor genes in this pest and suggested that it may use the geomagnetic field for orientation during nocturnal flight. Additionally, we identified molecular signatures that regulate the migratory syndrome coordinating reproduction and flight. These findings contribute to our understanding of developmental plasticity and long-distance migration in nocturnal insect pests.