Mutualism between insects and fungi drives insect evolutionary diversification and niche expansion;for invasive insects,however,mechanisms by which they maintain mutualistic relationships with beneficial fungi have no...Mutualism between insects and fungi drives insect evolutionary diversification and niche expansion;for invasive insects,however,mechanisms by which they maintain mutualistic relationships with beneficial fungi have not been clearly explored.Here,we report that an invasive herbivorous insect,the red turpentine beetle(RTB),with its co-invasive mutualistic fungus,Leptographium procerum,has newly acquired a set of sympatric fungi during invasion,which could potentially outcompete the RTB mutualistic fungus.Host pine Pinus tabuliformis exhibited more rosin-based responses to the sympatric fungi than to RTB mutualistic fungus and,in return,the rapidly induced rosin suppressed the sympatric fungi more significantly than L.procerum.In addition,from direct fungal pairing competitions,we found that the antagonistic effects of sympatric fungi on L.procerum were drastically reduced under induced rosin defense.Our results together with previous findings imply that pine oleoresin defense(turpentine and rosin)might have been exploited by the invasive mutualistic fungus L.procerum,which helps to explain its invasion success and,by extension,its mutualistic partner RTB in China.展开更多
基金The authors thank Mrs Xiaowei Qin(Institute of Zoology,CAS)for assistance in chemical analyses.The authors also wish to thank the staff at Tongzhou nursery stock base for providing directions in pine seedling cultivation.This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB11050000)the National Natural Science Foundation of China(31110103903,31222013 and 31170610).
文摘Mutualism between insects and fungi drives insect evolutionary diversification and niche expansion;for invasive insects,however,mechanisms by which they maintain mutualistic relationships with beneficial fungi have not been clearly explored.Here,we report that an invasive herbivorous insect,the red turpentine beetle(RTB),with its co-invasive mutualistic fungus,Leptographium procerum,has newly acquired a set of sympatric fungi during invasion,which could potentially outcompete the RTB mutualistic fungus.Host pine Pinus tabuliformis exhibited more rosin-based responses to the sympatric fungi than to RTB mutualistic fungus and,in return,the rapidly induced rosin suppressed the sympatric fungi more significantly than L.procerum.In addition,from direct fungal pairing competitions,we found that the antagonistic effects of sympatric fungi on L.procerum were drastically reduced under induced rosin defense.Our results together with previous findings imply that pine oleoresin defense(turpentine and rosin)might have been exploited by the invasive mutualistic fungus L.procerum,which helps to explain its invasion success and,by extension,its mutualistic partner RTB in China.
