Uncertainties in the effectiveness of biological control of stem borers under different climate change scenarios in Eastern Africa

Abstract

Climate change (CC) is expected to significantly affect biodiversity and ecosystem services. Adverse impacts from CC in the Global South are likely to be exacerbated by limited capacities to take adequate adaptation measures and existing developmental challenges. Insect pests today are already causing considerable yield losses in agricultural crop production in East Africa. Studies have shown that insects are strongly responding to CC by proliferation, shift in distribution, and by altering their phenology, which is why an impact on agriculture can be expected. Biological control (BC) has been proposed as an alternative measure to sustainably contain insect pests, but few studies predict its efficacy under future CC. Using the species maximum entropy modeling (Maxent) approach, we predict the current and future distribution of three important lepidopteran stem borer pests of maize in Eastern Africa, i.e., Busseola fusca (Fuller, 1901), Chilo partellus (Swinhoe, 1885), and Sesamia calamistis (Hampson, 1910), and two parasitoids that are currently used for BC, i.e., Cotesia flavipes (Cameron, 1891) and Cotesia sesamiae (Cameron, 1906). Based on these potential distributions and data collected during household surveys with local farmers in Kenya and Tanzania, also future maize yield losses are predicted for a business-as-usual scenario and a sustainable development scenario. We found that BC of the stem borer pests by C. flavipes and C. sesamiae will be less effective under more severe CC resulting in a reduced ability to curb maize yield losses caused by the stem borers. These results highlight the need to adapt BC measures to future CC to maintain its potential for environmentally friendly pest management strategies. The findings of this research are thus of particular relevance to policymakers, extension officers, and farmers in the region and will aid the adaptation of smallholder agricultural practices to the impacts of CC.

Global climate change‐driven impacts on the Asian distribution of Limassolla leafhoppers, with implications for biological and environmental conservation

“…The current 19 bioclimatic variables are derived from the average values of data from 1970 to 2000 (Jendritzki et al., 2023 ; Ramasamy et al., 2022 ). For future bioclimatic variables, they are based on Coupled Model Intercomparison Project Phase 6 (CMIP6) downscaled future climate projections (Eyring et al., 2016 ), and are from two periods (2050s and 2090s) under SSP1‐2.6 and SSP5‐8.5 scenarios.…”

“…For future bioclimatic variables, they are based on Coupled Model Intercomparison Project Phase 6 (CMIP6) downscaled future climate projections (Eyring et al., 2016 ), and are from two periods (2050s and 2090s) under SSP1‐2.6 and SSP5‐8.5 scenarios. The provided data for the two future prediction periods are averages of monthly values that were recorded over 20‐year time frames (2041–2060 and 2081–2100) (Fick & Hijmans, 2017 ), reflecting both nearer future and longer term climatic conditions (Jendritzki et al., 2023 ; Riahi et al., 2017 ; Zhang et al., 2019 ). Moreover, the SSP1‐2.6 scenario presents an optimistic outlook for global sustainable development in the future, whereas the SSP5‐8.5 scenario represents the most adverse emission scenario, which ignores the mitigation of climate change and mandates extensive adaptation measures (Riahi et al., 2017 ).…”

“…For future bioclimatic variables, they are based on Coupled Model Intercomparison Project Phase 6 (CMIP6) downscaled future climate projections (Eyring et al, 2016), and are from two periods (2050s and 2090s) under SSP1-2.6 and SSP5-8.5 scenarios. The provided data for the two future prediction periods are averages of monthly values that were recorded over 20-year time frames (2041-2060 and 2081-2100) (Fick & Hijmans, 2017), reflecting both nearer future and longer term climatic conditions (Jendritzki et al, 2023;Riahi et al, 2017;Zhang et al, 2019).…”