Efeito da conversão de campos nativos por pastagens exóticas e o uso de ivermectina na relação entre ácaros Macrochelidae (Acari: Mesostigmata) e Dichotomius bos (Coleoptera: Scarabaeidae)

Abstract

The Cerrado biome harbors high biodiversity and plays a fundamental role in maintaining ecological processes and providing ecosystem services. However, the conversion of natural areas into agro-pastoral systems and the adoption of intensive management practices have promoted significant changes in the structure and functioning of these environments, particularly affecting edaphic biota and soil-associated ecological interactions. Among the organisms potentially impacted by these changes are dung beetles of the subfamily Scarabaeinae and phoretic mites of the family Macrochelidae, functionally interdependent groups that are important for the dynamics of bovine dung. This dissertation aimed to evaluate the effects of the conversion of native pastures into exotic pastures and the use of ivermectin in livestock management on population metrics and phoretic relationships between the dung beetle Dichotomius bos (Coleoptera: Scarabaeidae) and associated Macrochelidae mites in cattle ranching areas in the region of Carrancas, Minas Gerais, Brazil. To this end, beetles were collected in areas with different pasture types and histories of ivermectin use, followed by the quantification and identification of phoretic mites associated with the sampled individuals. A total of 8,776 mites associated with 288 individuals of Dichotomius bos were collected, belonging to eight Macrochelidae species. The results indicated that ivermectin use was associated with a reduction in the abundance of the phoretic mite community, whereas the conversion of native pastures into exotic pastures did not result in significant differences in the evaluated metrics. Species richness remained constant among the different management types, possibly due to the approach focusing on a single host species. Overall, the results demonstrate that livestock management practices can influence the structure of edaphic communities and the ecological interactions associated with bovine dung. Thus, this study contributes to a better understanding of the effects of anthropization on Cerrado edaphic biodiversity and reinforces the importance of considering interspecific interactions in ecological assessments of pastoral systems.