| 英文摘要: | This project will document the world-wide diversity of ambrosia fungi - the nutritional symbionts of the wood-boring fungus-farming ambrosia beetles. The farming of fungi has evolved in at least 12 different bark beetle groups, and these groups have radiated into more than 3,500 species. Despite the evolutionary success of this relationship, estimates suggest that the identity of the fungal symbiont is unknown for over 90% of beetles. Global movement of wood products has made many ambrosia beetles invasive, and many of the symbiotic fungi have become pathogens to tree crops. This project will document the ambrosia beetle-fungal symbiosis and characterize the fungal community for each ambrosia beetle genus using new molecular and culturing techniques. Two graduate students will be trained in field and laboratory techniques. The project will also disseminate research findings through an exhibit of beetle calligraphy at the Harn Museum of Modern Art in Gainesville, FL, and a national citizen science project entitled 'Backyard Bark Beetles'. Researchers will also enhance international collaboration and infrastructure by running an ambrosia beetle identification workshop in tropical Asia to help inspectors identify the most invasive species.
The first aim of this project is to comprehensively sample ambrosia beetle-fungal symbioses to investigate the level of symbiont specificity. Three globally-invasive ambrosia beetle-fungus complexes will then be sampled to investigate how the fungal symbiont community has changed over time following vector dispersal, invasion, and contact with new communities. The third and ultimate goal of the project is to use phylogenetic and comparative methods to reconstruct the pattern of ambrosia beetle-fungus coevolution. With new data on fungus communities, it will be possible to compare the influence of beetle phylogeny, geographic origin, latitude and other factors on beetle-fungus relationships. This project will implement a series of methods to achieve the research goals, including high-throughput DNA metabarcoding, a new 'RNA metabarcoding' approach to investigate fungal metabolic prominence, and a RADseq-based approach to reconstruct population genetic history, Together, this research will produce a comprehensive dataset on the identity and movements of ambrosia and their fungal symbionts in both their native and invaded regions that will provide essential baseline data to help control the global impact of both ambrosia beetles and ambrosia fungi. |