Biogeography of cereal stemborers and their natural enemies: forecasting pest management efficacy under changing climate

Abstract

Background Climate warming presents physiological challenges to insects, manifesting as loss of key life‐history fitness traits and survival. For interacting host–parasitoid species, physiological responses to heat stress may vary, thereby potentially uncoupling trophic ecological relationships. Here, we assessed heat tolerance traits and sensitivity to prevailing and future maximum temperatures for the cereal stemborer pests, Chilo partellus, Busseola fusca and Sesamia calamistis and their endo‐parasitoids, Cotesia sesamiae and Cotesia flavipes. We further used the machine learning algorithm, Maximum Entropy (MaxEnt), to model current and potential distribution of these species. Results The mean critical thermal maxima (CTmax) ranged from 39.5 ± 0.9°C to 44.6 ± 0.6°C and from 46.8 ± 0.7°C to 48.5 ± 0.9°C for parasitoids and stemborers, with C. sesamiae and Ch. partellus exhibiting the lowest and highest CTmax respectively. From the current climate to the 2050s scenario, parasitoids recorded a significant reduction in warming tolerance compared with their hosts. Habitat suitability for all stemborer–parasitoid species was spatially heterogeneous under current and future climatic scenarios. Cotesia sesamiae C. flavipes and B. fusca exhibited significant habitat loss, whereas Ch. partellus and S. calamistis showed a significant habitat gain under future 2050s predictions. Model metrics based on mean area under the curve ranged from 0.72 to 0.84 for all species, indicating a good predictive performance of the models. Conclusion These results suggest C. sesamiae and C. flavipes may face survival constraints or extirpation compared with their pest hosts when environmental temperature reaches their upper thermal limits earlier, likely reducing pest regulation through density‐mediated effects. The results demonstrate potential destabilization of stemborer–parasitoid trophic systems potentially compromising biocontrol efficacy under climate warming. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Distribution patterns of Phytoseiulus persimilis in response to climate change

“…61 MaxEnt has emerged as a powerful method for determining the impacts of climate change on biological agents. 34,[62][63][64] This study evaluated the suitability of potential habitats worldwide for P. persismilis under current and future climate change scenarios for the first time. The findings indicate that the habitat suitability for P. persimilis currently was consistent with historical presence data, indicating the reliability of this model.…”

Understanding climate change effects on the potential distribution of an important pollinator species, Ceratina moerenhouti (Apidae: Ceratinini), in the Eastern Afromontane biodiversity hotspot, Kenya

“…In the RF model, the prediction is achieved by selecting the highest probability occurrence value from multiple decision trees (Muthoni et al, 2021). On the other hand, MaxEnt predicts the species occurrence by finding the largest spread (maximum entropy) (Mutamiswa et al, 2022;Phillips et al, 2017) while SVM uses a hyperplane to estimate the divergence of class groupings for the prediction (Hastie et al, 1994;Vapnik, 1979). These three algorithms were selected in this study because they are widely used in conducting complex output predictions with relatively high modeling accuracies for regression and classification (Abdel-Rahman et al, 2013).…”

“…Of particular concern to modeling biological species is that many species, mainly insects, will likely depend on the prevailing climate conditions (Volis and Blecher, 2021). These conditions usually define most geographical distribution noted in numerous species' distribution modeling outputs (Mutamiswa et al, 2022;Otieno et al, 2019). Among others, vegetation composition, precipitation, temperature, and altitude have been reported by earlier studies as critical environmental factors that affect the ability of insect pests to adapt to an area and eventually their distribution depending on their tolerable thresholds (Azrag et al, 2018;Otieno et al, 2019).…”