Implications of climate change for environmental niche overlap between five Cuscuta pest species and their two main host crop species Chaonan Cai1, 2, Jianhua Xiao3, Jizhong Wan4, Zichun Ren2, Mark van Kleunen1, 2, 5, Junmin Li1, 2, * 1 School of Advanced Study, Taizhou University, Taizhou, Zhejiang, 318000, China 2 Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou, Zhejiang, 318000, China 3 Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas, JiaYing University, Mei Zhou, Guangdong, 514015, China 4 State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, Qinghai, 810016, China 5 Department of Biology, University of Konstanz, Konstanz, 78464, Germany * Correspondence: Junmin Li, lijmtzc@126.com Abstract    Some parasitic plants are major pests in agriculture, but how this might be affected by climate change remains largely unknown. In this study, we assessed this for five generalist holoparasitic Cuscuta species (Cuscuta approximata, C. australis, C. chinensis, C. europaea, C. japonica) and two of their main Leguminosae host crop species (Glycine max and Medicago sativa). For each of the five Cuscuta species and the two crop species, we ran MaxEnt models, using climatic and soil variables to predict their potential current distributions and potential future distributions for 2070. We did this for multiple climate-change scenarios, and tested for the overlapping suitable ranges changes of the two crops and the five parasites. We found that annual mean temperature and isothermality are the main bioclimatic factors determining the suitable habitats of Cuscuta and its host plants. For both host species, the marginally to optimally suitable area will increase by 2070 for all four RCP scenarios. For most of the Cuscuta species, the marginally to optimally suitable area will also increase. Althoug C. australis will loose suitable area, the degree of suitability will actually increase. As the suitable area for both the hosts and the parasites will overall increase, Schoener¨s D, indicating the relative overlap in suitable area, will change to only a limited degree. However, the absolute area of potential niche overlap may increase up to six-fold by 2070. Overall, our results indicate that larger parts of the globe will become suitable for both host species, but that they could also suffer from Cuscuta parasitism in larger parts of their suitable ranges. These results might improve the management and control of parasitic species, and provide guidance to the protection of the host crops. Keywords: Potential habitat; Climate change; Cuscuta; Environmental niche overlap; Maximum entropy model; Parasitic plants Funding   This work was supported by the Ten Thousand Talent Program of Zhejiang Province (Grant No. 2019R52043) and the National Natural Science Foundation of China (Grant No. 30800133).