Decision Support System for Fitting and Mapping Nonlinear Functions with Application to Insect Pest Management in the Biological Control Context

Abstract

The process of moving from experimental data to modeling and characterizing the dynamics and interactions in natural processes is a challenging task. This paper proposes an interactive platform for fitting data derived from experiments to mathematical expressions and carrying out spatial visualization. The platform is designed using a component-based software architectural approach, implemented in R and the Java programming languages. It uses experimental data as input for model fitting, then applies the obtained model at the landscape level via a spatial temperature grid data to yield regional and continental maps. Different modules and functionalities of the tool are presented with a case study, in which the tool is used to establish a temperature-dependent virulence model and map the potential zone of efficacy of a fungal-based biopesticide. The decision support system (DSS) was developed in generic form, and it can be used by anyone interested in fitting mathematical equations to experimental data collected following the described protocol and, depending on the type of investigation, it offers the possibility of projecting the model at the landscape level.

Temperature-dependent modelling and spatial prediction reveal suitable geographical areas for deployment of two Metarhizium anisopliae isolates for Tuta absoluta management

“…Mathematical models have become an important tool for understanding and predicting the virulence and suitable application areas of entomopathogenic fungi against insect pests of economic importance often occurring in unpredictable environmental conditions 31 , 45 . Here, we used T. absoluta occurrence in East Africa 4 to model the virulence of the candidate isolates (ICIPE 18 and ICIPE 20) against the pest.…”

“…An open-source computer-aided tool built on R-codes and Java interface, the entomopathogenic fungi application (EPFA) software version 1.0 45 was used for modelling the virulence of the fungal strains (ICIPE 18 and ICIPE 20) against adult T. absoluta . The recorded mortality was plotted against the corresponding temperature values from which nonlinear models were fitted function to the observed data 45 . The model parameters were estimated by fitting equations to the recorded mortality and the corresponding temperature values.…”

“…The model parameters were estimated by fitting equations to the recorded mortality and the corresponding temperature values. Eighty two (82) models were fitted to the data and the best-fitted models were selected based on their coefficient of determination R 2 , adjusted R 2 , Akaike’s information criteria (AIC), the root-mean-squared error (RMSE) and residual sum of squares (RSS) 45 . In addition, nonlinear models allowed the assessment of the minimum temperature threshold ( T min ) and the maximum temperature threshold ( T max ).…”

“…To predict the spatial virulence of each fungal isolate, the temperature-dependent mathematical expression obtained during the modelling step was run at each grid of the raster files of Kenya, Tanzania and Uganda using the monthly minimum and maximum temperature datasets obtained from WorldClim ( http://www.worldclim.org/ ). The gridded temperature datasets were loaded into EPFA software, simultaneously extracted from the database and then organized in matrix format using longitude as column and latitude as a row 45 . A point object picks the temperature-dependent mathematical expression of the virulence for the isolates and this is consecutively applied in each geographical coordinate of the grid.…”

“…A point object picks the temperature-dependent mathematical expression of the virulence for the isolates and this is consecutively applied in each geographical coordinate of the grid. The results were converted into ASCII file format (.asc) and transferred into an open source software Q-GIS 60 for visualization 45 . The virulence map was produced for Kenya, Tanzania and Uganda after completing the fitting process.…”