Local niche, geographic barriers, or both in structuring a tropical forest metacommunity of cockroaches (Blattodea non-Termitoidae)?

Amazonian rivers play a crucial role in determining species turnover, as they serve not only as geographic barriers but also contribute to disturbance and variation in forest structure through their erosion and sediment accumulation dynamics. However, their role as geographic barriers varies according to the life history of the taxa being studied. Cockroaches (Blattodea non-Termitoidea) are one of the ancient groups of insects. These insects exhibit a variety of life forms (apterous, brachypterous, and macropterous) and lifestyles (inhabiting holes, galleries, caves, canopies, plant debris, ant nests, and barks). This study seeks to unravel the role of local niche factors and rivers as geographic barriers and structuring factors of cockroach metacommunities in the Amazon. We collected cockroaches in four different basins in Madre de Dios, Peru. To determine which factor is structuring the communities, we will use the Dispersal Niche Continuum Index. We will also identify the main beta diversity component (taxonomic replacement or nestedness). To determine the role of rivers as effective geographic barriers, we will measure and quantify gene flow among populations. We will determine its association with morphological characteristics (such as body length and wing length) and habitat preferences. We expect taxonomic replacement across subcommunities caused by dispersal limitation and barriers, and species that are common in different sites will show population genetic differentiation dependent on their dispersal capacity (which could be linked with body length, wing length, and habitat).