Insecticide resistance, genetic diversity, and ecological niche distribution associated with the co-occurrence of rice stink bugs in Neotropics

• Ano de defesa: 2022
• Autor(a) principal: Vieira, Juliana Lívia
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Oebalus poecilus; Oebalus ypsilongriseus; Resistência aos inseticidas; Diversidade genética; Percevejo (Inseto) - Controle; Percevejo (Inseto) - Distribuição geográfica - Modelos; Entomologia agrícola
• Link de acesso: https://locus.ufv.br//handle/123456789/32151; https://doi.org/10.47328/ufvbbt.2023.065

Anthropogenic-mediated climate change generally favors the spread and establishment of species better adapted to warmer conditions, while global connectivity increases the likelihood of some species expansion. Additionally, agricultural ecosystems offer ample opportunities for pest species to settle due to the relative impoverishment of local native species and the high availability of resources for better- adapted herbivores. Neotropical rice fields and the rice stink bugs Oebalus poecilus and O. ypsilongriseus provide a scenario in which apparent area expansion and trade- offs are occurring, favoring the establishment of a species complex, and of which the belated perception of the problem could lay significant economic and management consequences. In light of the main aspects of O. poecilus and O. ypsilongriseus biology and management, the objective of this thesis is to understand the factors mediating the distribution and overlap of these species. For that, the levels of thiamethoxam insecticide resistance and control failure likelihood were geographically assessed, as were each species' genetic diversity and population structure, attempting to recognize their relative occurrence, potential prevalence, and the likelihood of range expansion. Furthermore, species distribution modeling was used to identify the main predictor variables for the rice stink bug's niche occurrence and overlap. Our findings revealed that resistance to the main insecticide used in their control, thiamethoxam, does not appear to be decisive in species differentiation and prevalence. Nor are genetic divergences found here, considering that both species presented similar levels of diversity and structuring. However, the phenotypic plasticity (or its limitation) expressed in the ecological niche of rice stink bugs appears to indicate that sensitivity to drier periods may be an essential component in the distribution and dominance of these species in Neotropical regions. Thus, by combining control failure likelihood estimates, insecticide resistance, and spatiotemporal dynamics, with population genetics and species distribution modeling, this study allows insights on the relative importance and potential impact of two closely-related species, which in turn could potentially minimize unsuitable pest management practices and rice production losses. Keywords: Genetic diversity. Insecticide resistance monitoring. Pest management. Species distribution modeling. Species overlap.