Movement ecology and functional relationships in natural enemies of Spodoptera frugiperda

• Grant number: 20/09495-6
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): August 01, 2020
• Effective date (End): February 28, 2023
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Cooperation agreement: Koppert Brasil
• Principal researcher: Wesley Augusto Conde Godoy
• Grantee: Maysa Pereira Tomé
• Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 18/02317-5 - Center for Excellence in Biological Control, AP.PCPE

Abstract

Genetically modified plants expressing Bt toxins have been an important tool in the control of lepidopteran pests, such as S. frugiperda. After ingesting the Bt plant, susceptible insects are eliminated and the remaining, resistant and heterozygous insects persist in the environment.The technology must ensure that non-target organisms, such as predators and parasitoids, are not harmed. However, the existence of adaptive cost in resistant and heterozygous genotypes, may reflect behavioral or biochemical changes, which would result in changes in trophic interactions.However, there is little information about the aspects involved in the interaction between S. frugiperda genotypes and their natural enemies. Studies of the dynamics of pest movement and behavior of parasitoids and predators, in the comparative context between Bt and non-Bt plants, can provide information about the vulnerability of the pest in the field.e of the ways to make inferences about the action of natural enemies on their prey and hosts, is through functional response experiments, which employ parameters that precede the success of the interaction between these organisms making it a relevant tool for biological control; and behavioral analysis. Thus, the present project aims to: (i) verify if there is a difference between the ecological patterns of the functional response of natural enemies in the face of the susceptible, resistant and heterozygous genotypes of S. frugiperda; (ii) evaluate the parasitism rate of C. flavicincta on the three host genotypes; (iii) to verify the behavioral relationship of P. nigrispinus and C. flavicincta, regarding the attack actions against the three pest genotypes; (iv) to propose a computational model that investigates specific scenarios in agricultural landscapes involving the movement of S. frugiperda.the functional response bioassays of P. nigrispinus and C. flavicincta will be carried out under laboratory conditions, where the S. frugiperda genotypes will be offered in different densities, for 24 hours. Subsequently, dead and parasitized prey will be accounted for by the predator and parasitoid.The experiment will be conducted in a randomized block design with five replications and data analysis will be done according to the adjustment of Holling's equations for functional responses of type II and III. Behavioral analysis will be done using video tracking using the EthoVision® software. The analysis of the movement of S. frugiperda in the proposed scenario will be studied from the development of a cellular automaton, written in computational language C. (AU)