A sensitivity analysis can categorize levels of parameter influence on a model's output. Identifying parameters having the most influence facilitates establishing the best values for parameters of models, providing useful implications in species modelling of crops and associated insect pests. The aim of this study was to quantify the response of species models through a CLIMEX sensitivity analysis. Using open-field Solanum lycopersicum and Neoleucinodes elegantalis distribution records, and 17 fitting parameters, including growth and stress parameters, comparisons were made in model performance by altering one parameter value at a time, in comparison to the best-fit parameter values. Parameters that were found to have a greater effect on the model results are termed “sensitive”. Through the use of two species, we show that even when the Ecoclimatic Index has a major change through upward or downward parameter value alterations, the effect on the species is dependent on the selection of suitability categories and regions of modelling. Two parameters were shown to have the greatest sensitivity, dependent on the suitability categories of each species in the study. Results enhance user understanding of which climatic factors had a greater impact on both species distributions in our model, in terms of suitability categories and areas, when parameter values were perturbed by higher or lower values, compared to the best-fit parameter values. Thus, the sensitivity analyses have the potential to provide additional information for end users, in terms of improving management, by identifying the climatic variables that are most sensitive.

Background: 'Neoleucinodes elegantalis' is one of the major insect pests of 'Solanum lycopersicum'. Currently, 'N. elegantalis' is present only in America and the Caribbean, and is a threat in the world's largest 'S. lycopersicum'-producing countries. In terms of potential impact on agriculture, the impact of climate change on insect invasions must be a concern. At present, no research exists regarding the effects of climatic change on the risk level of 'N. elegantalis'. The purpose of this study was to develop a model for 'S. lycopersicum' and 'N. elegantalis', utilizing CLIMEX to determine risk levels of 'N. elegantalis' in open-field 'S. lycopersicum' cultivation in the present and under projected climate change, using the global climate model CSIRO-Mk3.0. Results: Large areas are projected to be suitable for 'N. elegantalis' and optimal for open-field 'S. lycopersicum' cultivation at the present time. However, in the future these areas will become unsuitable for both species. Conversely, other regions in the future may become optimal for open-field 'S. lycopersicum' cultivation, with a varying risk level for 'N. elegantalis'. Conclusion: The risk level results presented here provide a useful tool to design strategies to prevent the introduction and establishment of 'N. elegantalis' in open-field 'S. lycopersicum' cultivation.

The whitefly, Bemisia tabaci, is considered one of the most important pests for tomato Solanum lycopersicum. The population density of this pest varies throughout the year in response to seasonal variation. Studies of seasonality are important to understand the ecological dynamics and insect population in crops and help to identify which seasons have the best climatic conditions for the growth and development of this insect species. In this research, we used CLIMEX to estimate the seasonal abundance of a species in relation to climate over time and species geographical distribution. Therefore, this research is designed to infer the mechanisms affecting population processes, rather than simply provide an empirical description of field observations based on matching patterns of meteorological data. In this research, we identified monthly suitability for Bemisia tabaci, with the climate models, for 12 commercial tomato crop locations through CLIMEX (version 4.0). We observed that B. tabaci displays seasonality with increased abundance in tomato crops during March, April, May, June, October and November (first year) and during March, April, May, September and October (second year) in all monitored areas. During this period, our model demonstrated a strong agreement between B. tabaci density and CLIMEX weekly growth index (GIw), which indicates significant reliability of our model results. Our results may be useful to design sampling and control strategies, in periods and locations when there is high suitability for B. tabaci.

Seasonal variations are important components in understanding the ecology of insect population of crops. Ecological studies through modeling may be a useful tool for enhancing knowledge of seasonal patterns of insects on field crops as well as seasonal patterns of favorable climatic conditions for species. Recently CLIMEX, a semi-mechanistic niche model, was upgraded and enhanced to consider spatio-temporal dynamics of climate suitability through time. In this study, attempts were made to determine monthly variations of climate suitability for 'Neoleucinodes elegantalis' (Guenée) (Lepidoptera: Crambidae) in five commercial tomato crop localities through the latest version of CLIMEX. We observed that N. elegantalis displays seasonality with increased abundance in tomato crops during summer and autumn, corresponding to the first 6 months of the year in monitored areas in this study. Our model demonstrated a strong accord between the CLIMEX weekly growth index (GIw) and the density of 'N. elegantalis' for this period, thus indicating a greater confidence in our model results. Our model shows a seasonal variability of climatic suitability for 'N. elegantalis' and provides useful information for initiating methods for timely management, such as sampling strategies and control, during periods of high degree of suitability for 'N. elegantalis'. In this study, we ensure that the simulation results are valid through our verification using field data.

The whitefly, Bemisia tabaci, is a major threat to tomato Solanum lycopersicum and ranks as one of the world's 100 most invasive pests. This is the first study of B. tabaci (Biotype B and Q) global distribution, focusing on risk levels of this invasive pest, in areas projected to be suitable for open field S. lycopersicum cultivation under climate change. This study aims to identify levels of risk of invasive B. tabaci for areas of suitability for open field S. lycopersicum cultivation for the present, 2050 and 2070 using MaxEnt and the Global Climate Model, HadGEM2_ES under RCP45. Our results show that 5% of areas optimal for open field S. lycopersicum cultivation are currently at high risk of B. tabaci. Among the optimal areas for S. lycopersicum, the projections for 2050 compared to the current time showed an extension of 180% in areas under high risk, and a shortening of 67 and 27% in areas under medium and low risk of B. tabaci, respectively, while projections for 2070 showed an extension of 164, and a shortening of 49 and 64% under high, medium and low risk, respectively. The basis of these projections is that predicted temperature increases could affect the pest, which has great adaptability to different climate conditions, but could also impose limitations on the growth of S. lycopersicum. These results may be used in designing strategies to prevent the introduction and establishment of B. tabaci for open-field tomato crops, and assist the implementation of pest management programs.

Species distribution models (SDMs) are valuable for the information they provide to reduce the potential negative effects of climatic factors on agricultural production systems. Such information may be used to prevent the entry and spread of invasive species in new areas, as well as to monitor regions with current occurrence. This is the first study of Tomato yellow leaf curl virus (TYLCV) global distribution, focusing on the risk of this disease in areas projected to be suitable for open field tomato (Solanum lycopersicum) and for whitefly (Bemisia tabaci - biotypes B and Q). TYLCV (Begomovirus) is an important virus transmitted by B. tabaci and poses a risk to S. lycopersicum cultivation worldwide. Despite the importance of TYLCV, the potential impact of climate change on the global distribution of TYLCV in agricultural crops remains unstudied. The aim of this study was to identify the invasion risk levels for TYLCV in areas optimally conducive for open field tomato cultivation and suitable for B. tabaci (biotypes B and Q) under projected climate changes for the years 2050 and 2070 using MaxEnt and the Global Climate Model (HadGEM2_ES, MIROC5 and CCSM4) under four scenarios (RCPs 2.6, 4.5, 6.0, and 8.5). Our results show that large regions are projected to be suitable for TYLCV in areas of suitability for B. tabaci and optimal for open field tomato cultivation. In the predictions, most areas with optimal conditions for S. lycopersicum and suitable for B. tabaci will be under medium suitability for TYLCV under climate change scenarios. This research may be useful to design strategies to prevent the introduction and establishment of TYLCV where the occurrence has not yet been reported.

Projections of climate change show some regions of the world getting warmer, colder, dryer or wetter. Consequently, the effects of climate change on insect pests can alter the threat to agricultural systems. As a result of changed climate, areas can become more or less suitable for insect pests. Neoleucinodes elegantalis is one of the major pests of solanaceous crops in South America. Host plants for N. elegantalis are widely present in South America, however, N. elegantalis is absent from many regions in South America. Hence, future climate effects on suitability for development and spread of N. elegantalis in South America should be investigated. Due to these reasons, we developed a model of the climate for N. elegantalis using CLIMEX software for South America using A2 Special Report on Emissions Scenarios (SRES) for 2030, 2050, 2070 and 2100 and using two models, CSIROMk3.0 and MIROC-H. The results of both models indicate that areas in South America that are climatically suitable at the present time will become climatically unsuitable for N. elegantalis by 2100 as a consequence of progressive increase of dry stress. This was confirmed using developmental bioassays, where survival was lowest at low relative humidity levels. There are also altering areas that are currently unsuitable that become suitable in the future. These results are helpful in developing future strategies to take advantage of new opportunities in solanaceous crops in regions that may be unsuitable for N. elegantalis and provide important information for anticipated possible risks of infestation of N. elegantalis.