Elevational Gradients as Natural Filters: Assemblage Structure and Diversity of Ambrosia beetles (Curculionidae: Scolytinae) on the Tacaná Volcano, Chiapas, Mexico

The interaction between environmental variables influences patterns of diversity and the composition of communities along the elevational gradient. However, there is a lack of evidence regarding how these diversity patterns in Scolytinae change in response to environmental changes associated with elevation. This study aims to evaluate the influence of environmental changes along an elevational gradient on the diversity and composition of Ambrosia beetles, testing the hypothesis that species assemblages are primarily driven by the interaction between environmental variables and vegetation structure. We sampled Scolytinae at five sites (650–3360 m a.s.l.) on Tacaná Volcano from February 2018 to January 2019. Sampling was conducted using five trap types, including ethanol-baited Malaise traps and interception traps. Data were analyzed using Hill numbers for alpha diversity, Bray–Curtis indices for beta diversity, and canonical correspondence analysis to evaluate the relationship between Scolytinae species abundance and environmental variables. We recorded a high richness with 82 species, a peak in diversity at mid-elevations in mesic montane forests (p < 0.05). The Scolytinae species pool is structured in three local assemblages, corresponding to different elevational landscapes, environmentally structured. Different environmental variables displayed some correlation with species dynamics. However, these factors alone were insufficient to explain patterns of species diversity. Their influence appears to depend on interactions with site-specific characteristics. These results highlight that elevational gradients act as environmental filters structuring Scolytinae assemblages primarily through species turnover rather than nested species loss.