Effects of Host Plant and Larval Density on Intraspecific Competition in Larvae of the Emerald Ash Borer (Coleoptera: Buprestidae)

ABSTRACT Competition for food, mates, and space among different individuals of the same insect species can affect density-dependent regulation of insect abundance or population dynamics. The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a serious invasive pest of North American ash (Fraxinus spp.) trees, with its larvae feeding in serpentine galleries between the interface of sapwood and phloem tissues of ash trees. Using artificial infestation of freshly cut logs of green ash (Fraxinus pennsylvanica Marshall) and tropical ash (Fraxinus uhdei [Wenzig] Lingelsh) with a series of egg densities, we evaluated the mechanism and outcome of intraspecific competition in larvae of A. planipennis in relation to larval density and host plant species. Results from our study showed that as the egg densities on each log (1.5–6.5cmin diameter and 22–25cmin length) increased from 200 to 1,600 eggs per square meter of surface area, larval survivorship declined from ≈68 to 10% for the green...