High-throughput identification of fungal communities associated with ambrosia beetles

Ambrosia symbiosis is one of the most diverse, abundant and widespread symbioses in the insect kingdom. Complex fungiculture has evolved several times in multiple groups of scolytine beetles. Yet the diversity of the fungal symbionts and the symbiotic specificity has not been addressed with adequate methods. There are only a few culture-based surveys of the ambrosia community diversity with limited capacity to describe the true diversity of fungi. To characterize the complexity of the beetle-fungus relationship as well as to test coevolutionary concepts we have examined the fungus community composition using a recently developed 454-based high-throughput screening of fungal rDNA amplicons. We have employed a double-marker approach to increase resolution of the method and to detect fungal members potentially missed by a single-marker amplification.  The first proof-of-concept study focused on  SE US populations of three important ambrosia beetles: Xylosandrus crassiuscullus, Xyleborus ferrugineus and Xyleborus affinis. All of these are economically important invasive species either in the US (X. c.) or elsewhere in the world. Sequencing data are being generated at the time of submitting this abstract. Understanding of the fungus community composition, promiscuity, and regional diversity is a critical step for understanding this unique symbiosis, as well as for understanding the invasion ecology of these species.