The economic and environmental threats posed by non-native forest insects are ever increasing with the continuing globalization of trade and travel; thus, the need for mitigation through effective biosecurity is greater than ever. However, despite decades of research and implementation of preborder, border, and postborder preventative measures, insect invasions continue to occur, with no evidence of saturation, and are even predicted to accelerate. In this article, we review biosecurity measures used to mitigate the arrival, establishment, spread, and impacts of non-native forest insects and possible impediments to the successful implementation of these measures. Biosecurity successes are likely under-recognized because they are difficult to detect and quantify, whereas failures are more evident in the continued establishment of additional non-native species. There are limitations in existing biosecurity systems at global and country scales (for example, inspecting all imports is impossible, no phytosanitary measures are perfect, knownunknowns cannot be regulated against, and noncompliance is an ongoing problem). Biosecurity should be a shared responsibility across countries, governments, stakeholders, and individuals.

Longhorn beetles are commonly moved among continents within wood packaging materials used in trades. Visual inspections carried out at points of entry often fail to detect exotic longhorn beetles as infested materials may have little or no sign of colonization. Black-colored traps baited with pheromones and host volatiles are thus used to improve chances of detection. Here we tested whether existing surveillance protocols for longhorn beetles can be further improved using trap colors different than black. Baited traps of eight different colors (i.e., grey, yellow, green, red, blue, brown, purple and black) were deployed in a randomized complete block design at 16 sites in northern Italy in 2019. A total of 6,001 individuals from 56 longhorn beetle species were trapped. In general, yellow and blue traps caught a significantly higher number of longhorn beetle species than black traps. In addition, trap color significantly affected species richness and abundance at the subfamily and species level, with mixed response mostly linked to the habit of visiting flowers for food. Flower-visiting longhorn beetles mainly exhibited clear preference for flower-related colors, i.e., yellow, green and blue, whereas non-flower-visiting species were more attracted by dark and long-wavelength-dominated colors, like red and brown. Our results clearly indicate that generic surveillance programs should not rely exclusively on black traps and that the use of more trap colors can strongly improve the chance of detecting native and exotic longhorn beetles potentially moved with trades.

Traps baited with attractive lures are increasingly used at entry-points and surrounding natural areas to intercept exotic wood-boring beetles accidentally introduced via international trade. Several trapping variables can affect the efficacy of this activity, including trap color. In this study, we tested whether species richness and abundance of jewel beetles (Buprestidae), bark and ambrosia beetles (Scolytinae), and their common predators (i.e., checkered beetles, Cleridae) can be modified using trap colors different to those currently used for surveillance of jewel beetles and bark and ambrosia beetles (i.e., green or black). We show that green and black traps are generally efficient, but also that many flower-visiting or dark-metallic colored jewel beetles and certain bark beetles are more attracted by other colors. In addition, we show that checkered beetles have color preferences similar to those of their Scolytinae preys, which limits using trap color to minimize their inadvertent removal. Overall, this study confirmed that understanding the color perception mechanisms in wood-boring beetles can lead to important improvements in trapping techniques and thereby increase the efficacy of surveillance programs.