Influences of climate warming on co-occurrence of Aphis glycines (Matsumura) and Tetranychus cinnabarinus (Boisduval) on different soybean strains in cold area of China
[Objectives] To investigate the effects of temperature increase on the occurrence of phytophagous arthropod pests, and their interspecific interactions, on soybean crops in cold areas of China in order to improve the long term prediction and forecasting of multiple local arthropod pest species. [Methods] We simulated climate warming in an artificial climatic chamber and investigated the effects of both high and low temperatures on the co-occurrence and interspecific interactions of Aphis glycines and Tetranychus cinnabarinus. In addition, we tested interactions between these two arthropod pest species on leaf discs from different soybean strains. [Results] The results of our experiments suggest that relatively low temperatures will benefit aphid populations but higher temperatures will benefit tetranychid mites. At higher temperatures the interspecific competition coefficient is predicted to decrease, that is to say, the environmental carrying capacity will increase significantly. Under current temperature conditions, the interaction between these two arthropod pest species should be defined as commensalism, i.e., they are likely to co-occur in the field, and the soybean aphid especially is more likely to outbreak while co-existing with the mite on local, pest-sensitive, soybean strains. In other words, there is a substantial difference in the resistance of different local soybean strains to arthropod pests. [Conclusion] These results suggest that:Although not currently an issue, there is a high risk of future outbreaks of several arthropod pests on soybean crops in cold areas of China. We need to prepare some management measures for the future, such as selecting pest resistant strains that are suitable for local cultivation.