4 DISCUSSION
M. alternatus is the primary beetle vector of PWD in Asia, a major disease invading the forests. This study describes the first of the population structure of M. alternatus at intermediate and fine scales using whole-genome resequencing. In addition, the relationships between host and nonhost landscapes and this species were analyzed at a fine scale, which clarified the influence of multiple scales and different landscape types on dispersal behavior, gene flow, and genetic diversity. The results suggested that host forests could facilitate gene flow and dispersal of this species in a heterogeneous landscape and that human-mediated actions via roads were also conducive to dispersal. However, nonhost forest, urban, and farmland landscapes had negative effects on gene flow and dispersal. The different responses of M. alternatus to the heterogeneous landscapes indicate the importance of fully considering tree species and human-mediated landscapes when designing and managing forests and also suggest that PWD can be predicted and controlled in advance by determining the distribution of landscape types.