Background/Question/Methods: The wood boring, xylomycetophagous ambrosia beetles are successful colonizers due to their cryptic behavior and inbreeding, resulting in multiple exotic species colonizing the eastern United States. The dynamics of these invaded communities are poorly understood hindering management and conservation.  This study describes the ambrosia beetle community in a central Missouri, oak-hickory forest.  Species richness, abundance and the relative contribution of native and exotic species were examined as influenced by stand age and topographic aspect, to determine the importance of site characteristics.  We expected that these site characteristics resulted in stand basal area, density and productivity differences and hence varied in their importance as ambrosia beetle habitat.  Twelve stands were used in a 2x2 factorial design with 6 stands of each treatment type:  stand age >69 or < 24 yrs and site aspect 22.5- 112.5° (N-NE) or 157.5-292.5° (S-SW).

Results/Conclusions: Twenty ambrosia beetle species were found in aerial traps during weekly collections from April- November, 2007 and March-November, 2008.  Five exotic species accounted for 86% of collected individuals.  Ambrosia beetle abundance was greater in older stands in 2007 and 2008 (p=0.005, p=0.009).  Little difference between young and older stands occurred between April-June, 2007 and 2008 but differences increased as the season progressed (p=0.043, p=0.040).  Exotic species were also more abundant in older stands in both years (p=0.010, 0.006) and differences in abundance between age treatments increased as the season progressed in 2008 (p=0. 013). Stand age did not affect the native contribution of the community.  Community species richness was greater in mature forest stands in 2007 (p=0.020) but not 2008. Aspect did not affect community abundance.  Native and exotic species responded differently to basal area. Older stands are an important habitat for native and exotic ambrosia beetles in oak-hickory forests owing to greater overstory basal area, larger trees, and less understory basal area. Greater host material abundance, diversity in size, and surface area in older stands are suggested reasons for the increased ambrosia beetle abundance.