Longhorn beetles and predatory clerid beetles attracted to a blend of longhorn beetle pheromone compounds in a Central European oak forest (Coleoptera: Cerambycidae, Cleridae)

A blend of longhorn beetle pheromones was tested as a generic attractant for multiple longhorn beetle species in a Central European oak forest. Overall, 21 cerambycid species totalling 1,250 specimens were captured using two trap types. Panel traps captured more beetles than funnel traps. Significantly more adults of Phymatodes testaceus (L.) (Cerambycinae) and Leiopus nebulosus nebulosus (L.) (Lamiinae) were caught in baited traps compared to controls. Significant numbers of four other species were caught in panel traps but not funnel traps. For the cerambycine Pyrrhidium sanguineum (L.), significantly more beetles were caught in treatment traps than controls. For the cerambycine Anaglyptus mysticus (L.), and lepturines Cortodera humeralis (Schaller) and Rhagium sycophanta (Schrank), the numbers of beetles caught in treatment or control traps were similar, indicating no attraction to the lure blend. Adults of a predatory clerid beetle Clerus mutillarius F. were caught in significantly larger numbers by both baited trap types in comparison to controls, totalling 1,514 specimens. Antennae of both sexes of C. mutillarius showed significant responses to 3-hydroxyhexan-2-one and 2-methylbutan-1-ol compared to solvent controls, and antennae from males also responded significantly to syn-2,3-hexanediol. Strong attraction of C. mutillarius suggests eavesdropping on the pheromones of cerambycids and that such attractant baits, without traps, might be used to manipulate the local population density of predators in a push-pull biological control program targeting wood-boring insects.