The effect of forest fragment quality on cerambycid occupancy and abundance

Handley, Kaitlin
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University of Delaware
Cerambycidae are a large family of beetles that have been studied in detail in recent years. They are of particular interest because there are a number of species that are important pests of silviculture. Many of these species are not native in the area in which they are considered pests. Therefore recent research has developed synthesized aggregation pheromones that attract a broad range of cerambycid species that can be used in sentinel traps in ports to detect non-native beetles before they can establish so that eradication is possible. These pheromone blends were used in this study to test these lures as possible sentinel traps for non-native cerambycids and to survey the cerambycids of Delaware. Field bioassays were conducted in collaboration with the USDA Forest Service FRAME project (Forest Fragments in Managed Ecosystems). The goal was to determine which species occurred in which forest fragments and predict what forest factors influenced abundance. Traps baited with pheromone blends and host plant volatiles were put out in 24 for sites for 22 weeks from April to September in 2012 and 2013. The catches in these traps were collected once a week. A total of 15,368 cerambycid beetles in 72 species were captured including one exotic species. The forest factors predicted to influence cerambycid abundance that were measured in each of the sites were tree species, patch size, and tree health. I tested these factors using AIC values from the unmarked package in R. Tree species and patch size were significant factors in determining cerambycid abundance on a species by species basis. Tree stress was not, but the visual cues that were used to determine health may have not been accurate enough to successfully predict cerambycid abundance.