Juan Du1, Charles T Anderson2, Chaowen Xiao3. 1. Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China. 2. Department of Biology, Pennsylvania State University, University Park, PA, USA. 3. Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China. cwxiao@scu.edu.cn.