"Manipulation of bottom-up and top-down interactions for the ecological management of Tuta absoluta (Lepidoptera: Gelechiidae)."
bottom-up, top-down, tritrophic interactions, Tuta absoluta, conservation biological control, landscape ecology
Bottom-up and top-down forces interact to regulate herbivorous insects’ populations in isolated, complementary and additive ways, and the isolated and interactive effects of these forces can be influenced by landscape characteristics, as well as by biotic and abiotic factors at the local level. Plant diversity (bottom-up), plant chemical defenses (bottom-up) and the activity of natural enemies (top-down) are examples of selective forces that act on herbivorous insects. Many pest management strategies make use of such forces in the context of agroecosystems. Tuta absoluta (tomato pinworm) stands out as an economically important pest insect of tomato crops. Efforts to manage the tomato pinworm have traditionally focused on chemical control. However, recent studies suggest that an association of biological control and other ecological management techniques provides the most promising strategy in the long run. Thus, understanding the ecological mechanisms involved in pest management strategies, as well as the effects of their interactions on crop quality, are essential steps for an efficient and sustainable agriculture. Therefore, this thesis aims to understand the interactions between bottom-up and top-down forces that regulate populations of the pest insect T. absoluta, in order to support ecological management strategies for this pest at different spatial scales. This thesis will be structured in three chapters. The first chapter will assess how plant diversity and landscape structure at different spatial scales affect the provision and enhancement of the natural biological control of T. absoluta in tomato crops. The second chapter will investigate the ecological mechanisms underlying the bottom-up/topdown interactions that modulate T. absoluta populations, based on the manipulation of such forces in controlled conditions. The third chapter will be a meta-analysis based on a systematized literature review that intends to investigate how bottom-up and top-down factors affect populations of T. absoluta in tropical agroecosystems.