Life in Decaying Wood: The Diversification and Conservation of Bess Beetles (Coleoptera: Passalidae) in the Neotropics

 Dr. Cristian Beza-Beza

Assistant Professor, UMN Dept of Entomology

Abstract

As we face a global biodiversity crisis, understanding the origins and resilience of specialized forest communities is vital for a sustainable future. In this presentation, we will provide an overview of how the Insect Biodiversity and Evolution lab contributes to the discovery of insect biodiversity while addressing fundamental questions in ecology and evolution. Our research is primarily focused on Passalid beetles, which are sub-social saproxylophagous beetles living and feeding inside rotting logs where they serve as ecosystem engineers by assisting and accelerating the carbon cycling sequestered on wood. In the Neotropics, geographic distribution of species within the family Passalidae is highly correlated with altitude, with broadly distributed fauna in the lowlands and narrowly distributed locally endemic fauna occurring at higher altitudes. As such passalid beetles have served as a model system for establishing conservation areas and play an essential ecological role in wood decomposition. Our research on the biogeography of Passalidae revealed the role of cloud forest sky-islands in driving Mesoamerican beetle diversification, evidenced by wing reduction and dispersal limitation. Subsequent studies examined altitudinal shifts in beetle communities on Guatemalan volcanoes, linking community changes to temperature and rainfall gradients. Integrating phylogenetic and distributional data has allowed us to characterize patterns of phylogenetic diversity and their alignment with conservation priorities. In current projects, we focus on the microbiome’s influence on saproxylophagy, examining bacterial symbionts’ distribution and potential semi-vertical inheritance. By examining the inheritance of bacterial symbionts essential for wood digestion, we highlight the intricate evolutionary interplay between insects, their microbes, and the forest carbon cycle.