Grasshopper community structure and the rising dominance of generalist species across vegetation types in a biodiversity hotspot

Grasshoppers are one of the most dominant and diversified groups in terrestrial ecosystems, of which they are potential bioindicators. In West-Central Africa and the Congo basin, the Acridomorpha fauna is dominated by Acrididae, Pyrgomorphidae, Thericleidae, and Ixalidiidae. This biodiversity is still understudied. The current study compared the grasshopper communities of four vegetation types in the Bangou district: crop field, fallowland, forest, and bare soil. Grasshoppers were sampled using sweep netting and identified in the laboratory using appropriate keys. The species composition was analyzed using several statistical indices: species richness, abundance and abundance distribution model, frequency of occurrence, diversity and similarity, SIMPER, and IndVal. A total of 48 species and 10 subfamilies from three families—Acrididae, Thericleidae, and Pyrgomorphidae—were recorded. Crop field and fallowland hosted the highest grasshopper richness and abundance, while forest and bare soil showed few taxa. Chrotogonus homalodemus served as a specialist or bioindicator of bare soil, whereas four species— Parapterotiltus minimoides , Pterotiltus coeruleocephalus , Parepistaurus sp., and Thericles sp.—indicated forest land. Polyculture enhances plant-resource diversity and expands ecological niches, allowing most generalist species to occur while only a few become rare or highly dominant. Overall, both the number and proportion of generalist species increased markedly with land-use intensification, while rare species occurred in lower proportions in the most disturbed habitats. In the Bangou district, habitat disturbance has increased pest activities of some taxa such as Eyprepocnemis plorans or Catantops melanostictus , whereas other threatened species (e.g., Parapetasia rammei and P. minimoides ) were confined to the remaining forest patches, emphasizing the need for sustainable land management.