The effect of forest fragment quality on the abundance and occupancy of cerambycid beetles

We evaluated the abundance and occupancy of long-horned beetles (Coleoptera: Cerambycidae) in  forest fragments in northern Delaware over two years. Most of these urban and suburban forests are part of the long-term FRAME (Forest Fragments in Managed Ecosystems) program, which comprises 30 sites in the Mid-Atlantic region of the eastern United States. These sites have been characterized with regards to soil, understory vegetation species and density, litter dwelling arthropods, and occurrence of amphibians, reptiles, birds, and mammals.  We also set up traps at the Port of Wilmington to see if there is a difference in cerambycid populations in an urban area by an active port that receives foreign imports. 

The family Cerambycidae contains a number of native and nonnative forest pests, many of which can be attracted to synthesized pheromones.  In each forest fragment at least one cross panel trap was baited with a combination of a synthesized blend of pheromone, known to attract certain genera of cerambycid beetles.  Beginning in the last week of April, we collected all insects found in our traps once a week, and refreshed treatments in accordance with protocols developed by Hanks and Millar.  We collected beetles over five months, covering the historically active time for cerambycids in the eastern US.  Using the R “unmarked” package, we have found that the most influential factor in cerambycid presence is tree species.