Microhabitat and seasonal influence on bess beetle (Coleoptera: Passalidae) assemblage in Altitudinal Atlantic Forest

Abstract Understanding the spatiotemporal distribution of diversity has been a significant challenge in the field of conservation biology. Presently, there exists a limited understanding of the spatial distribution of passalid beetles within decomposing logs, as well as their distribution in microhabitats such as the cortex, heartwood and trunk–soil interface. Moreover, there is a scarcity of studies that delve into the temporal distribution patterns of passalid beetles. We evaluate the effect of seasons of the year and microhabitats on the distribution of passalid in an Altitudinal Atlantic Forest. More specifically, the effects of the period of the year and microhabitats were analysed on an assemblage scale and population structure scale. Collections were actively conducted monthly, during dry and rainy seasons, and distinct microhabitats of logs (tree cortex, heartwood and trunk–soil interface) were sampled. We discovered passalid galleries within 235 logs, housing a total of 785 individuals representing nine species across six genera and two tribes. Within the three examined microhabitats, the heartwood and cortex harboured the majority of individuals. In contrast, the trunk–soil interface microhabitat displayed reduced diversity and abundance and the absence of indicator species, exhibiting a distinct community structure compared with the others. The dry season stood out with a greater number of individuals, underscoring the influence of precipitation on passalid activity in this study. Our study contributes to understanding the ecological dynamics of these insects and evaluating their resilience to current landscape transformations on the planet.