Analysis of non-target beetle species collected on pheromone-baited adhesive panels in two mixed oak forest stands infested with <i>Lymantria dispar</i> (Lepidoptera: Erebidae) in southern Romania

Amid the ongoing decline of oak forests across Europe, implementing measures to detect, monitor, and prevent infestations by defoliating insect species has become increasingly urgent. Among these species, Lymantria dispar (Linnaeus, 1758) represents one of the most significant threats to oak forests. Adhesive panel traps baited with pheromone lures are commonly used for monitoring, but their non-selective nature leads to unintended captures of non-target insects, including Coleoptera. This study was conducted during the 2023 flight season (June-August) in two outbreak-affected oak stands in southern Romania (Baba Ana and Tatina). Twelve atraDISPAR-baited sticky panels were installed per sample plot, arranged in three replicates of four panels each in a square layout. A total of 1,844 beetles from 21 non-target beetle species belonging to 11 families were collected and classified by feeding preference. Agrilus angustulus (Illiger, 1803) (Buprestidae), one of the species associated with oak decline in Western Europe, was the most abundant among the species identified. Species richness was comparable (13 in Tatina, 12 in Baba Ana), but abundance varied greatly (139 specimens in Tatina vs. 1,705 in Baba Ana). The observed attraction of several secondary pest beetles suggests that adhesive panel traps may serve not only in L. dispar monitoring but also as a potential tool for assessing broader forest health.