Developing trapping protocols for wood-boring beetles associated with broadleaf trees

Longhorn and jewel beetles are often moved intercontinentally within woody materials. The common use of hardwoods in solid wood-packaging requires efficient trapping protocols for broadleaf-associated species. We tested the effect of lure (ethanol vs multi-lure), trap color (green vs purple), and trap height (understory vs canopy) on the longhorn and jewel beetle species trapped in multi-funnel traps set up in both seminatural forests and reforested forests in Italy. Traps were deployed in a 2 × 2 × 2 factorial scheme, and the eight different treatments were replicated 17 times in a randomized complete block design, in which each block was a different site. Thirty-five longhorn beetle species (2 non-native) and 15 jewel beetle species (all native) were trapped. The multi-lure was more effective than ethanol at detecting most longhorn beetles at both the species and subfamily level (except Lepturinae), but had no effect on the detection of jewel beetles. Trap color affected both jewel (green better than purple) and longhorn beetles with mixed responses among subfamilies. Species richness and/ or abundance of both families was greater in the canopy than the understory, but trends were more heterogeneous at lower taxonomic levels (i.e., significant effect on Cerambycinae and Lepturinae but not on Lamiinae). In general, we showed that green multi-funnel traps baited with multi-lure, and setup in the canopy may be an efficient trapping protocol for European longhorn and jewel beetles associated with broadleaf trees. This information can increase efficacy of early-detection programs carried out both inside and outside of Europe.