Acknowledgements
We are grateful to members of the Department of Population biology for comments on the previous version of the manuscript. This research was supported by the Czech Science Foundation project GAČR 17-11281S and partly by the institutional research project RVO 67985939. JXQ was financially supported by the National Natural Science Foundation of China (31200249), National Special Program on Basic Works for Science and Technology of China (2015FY1103003-6).