Vertical stratification of bark beetle and associated insect communities within simulated lightning struck longleaf pine trees

Dead or dying pine trees are colonized over space and time by a variety of insect species, the majority of which are beetles. Some of these insects exhibit a preference for activity in either the canopy or understory forest layers. At the landscape scale, lightning creates widespread point sources for beetle colonization via single struck trees. These trees may represent an important reproductive resource for endemic beetle populations and, consequently, their associated community of insect species. The vertical stratification of insect activity in forests may affect the colonization dynamics of pine trees by bark beetles and their associated insects at a critical point in their life history. We used detonation cord simulated lightning strikes on longleaf pine (Pinus palustris Miller) trees as an opportunity to study the degree to which insects colonize a singular tree in a forest setting. We used unbaited funnel traps hung at four heights (0, 5, 10, and 15 m) in longleaf pine trees assess the activity and vertical distribution of different insect species during the colonization process of dead or dying trees. Several important herbivore species showed a vertical stratification in their colonization habits. The pattern was less defined for associated predatory or parasitic insects. Initial colonization dynamics of dying pine trees can have important implications for the associated community of insects that assemble around these colonization events as well as the succession of deadwood organisms that inhabit these resources for many years after.