Richness and composition of Coleoptera (Curculionidae, Scarabaeidae and Passalidae) in a tropical coastal mountain range in Colombia

Current conservation challenges have made it imperative to document insect fauna, which faces many threats, especially in megadiverse countries like Colombia. However, exploring large taxonomic groups at a regional scale imposes technical and budgetary limitations that are difficult to overcome. In this project, academics and members of the Arhuaca indigenous community of the Sierra Nevada de Santa Marta (SNSM), in Colombia, joined forces to study three groups of beetles (Coleoptera): weevils (family Curculionidae), bess beetles (family Passalidae) and dung beetles (Scarabaeidae, Scarabaeinae). These taxa have contrasting life histories and high ecological relevance constituting potential bioindicator organisms to track conservation status, anthropogenic disturbance and ecological changes. The composition of two families and one subfamily of beetles was studied in two hydrographic basins of the SNSM, comprising nine sampling stations at elevations of 0–2000 m above sea level (m a.s.l.). For the family Curculionidae, 288 records of 666 individual belonging to 12 subfamilies, 35 tribes, 57 genera and 110 putative species (morphospecies) were recorded. All morphoespecies were assigned to subfamily, 99 to tribe and 97 to genus. The genera Conotrachelus Dejean, 1835 (Molytinae), Geraeus Pascoe, 1889 (Baridinae), Anchonus Schönherr, 1825 (Molytinae) and Anones Casey, 1922 (Baridinae) are represented by the highest numbers of species. The genera Penestes Schönherr, 1825 (Brachycerinae), Plectrophoroides Wibmer & O’Brien, 1986 (Entiminae) and Cossonus Clairville, 1798 (Cossoninae) accounted for 54% of the abundance. In Passalidae, 240 records of 12 species (four endemic) were found. In this case, all 1035 specimens were identified to the species level. Passalus Fabricius was the richest and most dominant genus, with seven species and 635 individuals. Finally, for Scarabaeinae, a total of 2435 records comprising 11885 individuals were obtained, representing 15 genera and 52 species, with all the records identified at least at the genus level. Onthophagus Latreille, 1802, Uroxys Westwood, 1842 and Canthidium Erichson, 1847 were the most abundant genera, together accounting for 85% of the individuals, whereas Canthon Hoffmannsegg, 1817, Onthophagus Latreille, 1802 and Canthidium were the most species-rich, representing 55% of the recorded species.