Maximizing Bark and Ambrosia Beetle (Coleoptera: Curculionidae) Catches in Trapping Surveys for Longhorn and Jewel Beetles

Abstract

Bark and ambrosia beetles are commonly moved among continents within timber and fresh wood-packaging materials. Routine visual inspections of imported commodities are often complemented with baited traps set up in natural areas surrounding entry points. Given that these activities can be expensive, trapping protocols that attract multiple species simultaneously are needed. Here we investigated whether trapping protocols commonly used to detect longhorn beetles (Coleoptera: Cerambycidae) and jewel beetles (Coleoptera: Buprestidae) can be exploited also for detecting bark and ambrosia beetles. In factorial experiments conducted in 2016 both in Italy (seminatural and reforested forests) and Canada (mixed forest) we tested the effect of trap color (green vs purple), trap height (understory vs canopy), and attractive blend (hardwood-blend developed for broadleaf-associated wood-boring beetles vs ethanol in Italy; hardwood-blend vs softwood-blend developed for conifer-associated wood-boring beetles, in Canada) separately on bark beetles and ambrosia beetles, as well as on individual bark and ambrosia beetle species. Trap color affected catch of ambrosia beetles more so than bark beetles, with purple traps generally more attractive than green traps. Trap height affected both beetle groups, with understory traps generally performing better than canopy traps. Hardwood-blend and ethanol performed almost equally in attracting ambrosia beetles in Italy, whereas hardwood-blend and softwood-blend were more attractive to broadleaf-associated species and conifer-associated species, respectively, in Canada. In general, we showed that trapping variables suitable for generic surveillance of longhorn and jewel beetles may also be exploited for survey of bark and ambrosia beetles, but trapping protocols must be adjusted depending on the forest type.

Recent advances toward the sustainable management of invasive Xylosandrus ambrosia beetles

“…Ethanol-baited traps are the predominant method for monitoring ambrosia beetle populations, including Xylosandrus spp. in ornamental nurseries (Reding et al, 2010(Reding et al, , 2011(Reding et al, , 2015, forests (Hauptman et al 2019;Martínez et al 2019;Marchioro et al 2020), and urban landscapes and parks (Klingeman et al 2017;Gugliuzzo et al 2019a). Several types of traps are commercially available, and homemade inexpensive bottle traps can be easily made and baited with lures (Egonyu and Torto 2018;Owens et al 2019b).…”

“…However, other Lindgren trap colors (e.g., green, purple) also have been used to trap other woodboring insects like emerald ash borer (Agrilus planipennis Fairmaire), and these alternative colors also will generally collect Xylosandrus spp. as long as the trap is baited with an ethanol lure (Francese et al 2013;Cavaletto et al 2020;Marchioro et al 2020). Indeed, most ethanol-baited traps have been shown suitable for monitoring the presence or absence of ambrosia beetle.…”

“…Several other factors can affect catch rates of Xylosandrus spp., including trap placement (Reding et al 2010;Klingeman et al 2017;Marchioro et al 2020;Miller et al 2020). Traps placed 0.5 m above the ground capture more X. germanus than those placed at 1.7 or 3.0 m (Reding et al 2010).…”

Monitoring Exotic Beetles with Inexpensive Attractants: A Case Study

“…If we consider the number of exotic species recorded in the last few years, and especially those collected fortuitously, it is clear that current monitoring strategies are ineffective at detecting several beetle families. It is for this reason that great effort has been invested in improving monitoring strategies, survey methods, and traps [ 18 , 19 ], with a focus on the main entry points such as seaports and airports (i.e., [ 20 , 21 ]). However, much of these recent developments have targeted primarily families of forest insects, mostly wood borers, such as Curculionidae: Scolytinae and Platypodinae, Cerambycidae, and Buprestidae (e.g., [ 22 , 23 , 24 ]).…”

Bark and Wood Boring Insects—Past, Present, and the Future Knowledge We Need

“…Something that had a similar effect at a larger scale, both on endemic and invasive Mediterranean pine bark beetle species [ 9 ]. As a recent study has concluded [ 10 ], a number of trapping variables, such as trap color, lure blend, and even height should be accordingly adjusted to maximize the efficacy of a surveillance program.…”