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.