Our study examined a total of 60 dead wood samples (Quercus spp.), collecting 30 samples each in summer and winter, and measured various environmental variables in the field. These samples were classified into three decay classes: fresh, intermediate, well-decayed. We sampled saproxylic beetles within the collected dead wood using emergence traps. Conducted a cluster analysis to explore their relationships of saproxylic beetle and environmental variables. Our results revealed that season and decay class were significant environmental variables affecting saproxylic beetle communities. These results highlight the sensitivity of saproxylic beetles to fluctuations of environment and climate. In summary, our study highlights the intricate relationships between environmental variables and saproxylic beetles and suggests that different types of dead wood should be maintained in forests.

In the forest ecosystem, trees are important components among many life forms, supporting biodiversity. This biodiversity is found not only in living trees but also in dead trees, where they provide rich environment for dead wood-associated organisms. Among saproxylic invertebrates, insects play pivotal roles in dead wood ecosystem and comprise of a huge proportion of diversity. In this study, we categorize Quercus dead wood into three decay classes, and seek to understand the association of saproxylic insect assemblages and different decay classes. Using emergence traps, we examine how many insect species and individuals appear in each decay class, and how insect assemblages change across the full range of decompositional stages of Quercus dead wood. This will highlight the importance of retaining various dead wood to conserve saproxylic biodiversity.