Exploiting trap color to improve surveys of longhorn beetles

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.

Simple SummarySeveral wood-associated insects are inadvertently introduced every year within wood-packaging materials used in international trade. These insects can cause impressive economic and ecological damage in the invaded environment. Thus, several countries use traps baited with pheromones and plant volatiles at ports of entry and surrounding natural areas to intercept incoming exotic species soon after their arrival and thereby reduce the likelihood of their establishment. In this study, we investigated the performance of eight trap colors in attracting jewel beetles and bark and ambrosia beetles to test if the trap colors currently used in survey programs worldwide are the most efficient for trapping these potential forest pests. In addition, we tested whether trap colors can be exploited to minimize inadvertent removal of their natural enemies. Our results confirmed that trap color strongly affects trapping performance. Overall, the trap colors currently adopted in most survey programs (i.e., green and black) are efficient only for certain beetle species, therefore there is a clear need to use additional trap colors to increase the range of species that can be effectively attracted. Moreover, we confirmed that many predators exploit the same visual cues as their preys, and thus trap color cannot be used as a variable to minimize bycatch.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.

Longhorn beetles are among the most important groups of invasive forest insects worldwide. In parallel, they represent one of the most well-studied insect groups in terms of chemical ecology. Longhorn beetle aggregation-sex pheromones are commonly used as trap lures for specific and generic surveillance programs at points of entry and may play a key role in determining the success or failure of exotic species establishment. An exotic species might be more likely to establish in a novel habitat if it relies on a pheromone channel that is different to that of native species active at the same time of year and day, allowing for unhindered mate location (i.e., pheromone-free space hypothesis). In this study, we first tested the attractiveness of single pheromone components (i.e., racemic 3-hydroxyhexan-2-one, racemic 3-hydroxyoctan-2-one, and syn-2,3-hexanediol), and their binary and tertiary combinations, to native and exotic longhorn beetle species in Canada and Italy. Second, we exploited trap catches to determine their seasonal flight activity. Third, we used pheromone-baited "timer traps" to determine longhorn beetle daily flight activity. The response to single pheromones and their combinations was mostly species specific but the combination of more than one pheromone component allowed catch of multiple species simultaneously in Italy. The response of the exotic species to pheromone components, coupled with results on seasonal and daily flight activity, provided partial support for the pheromone-free space hypothesis. This study aids in the understanding of longhorn beetle chemical ecology and confirms that pheromones can play a key role in longhorn beetle invasions.

Baited traps are a basic component of both specific and generic surveillance programs targeting wood-boring beetles at risk of introduction to new habitats because of global trade. Among the numerous protocols developed over the years for generic surveillance of longhorn beetles, jewel beetles, and bark and ambrosia beetles is the simultaneous use of black multi-funnel traps set up in the understory and green multi-funnel traps set up in the canopy of forested areas surrounding ports and other entry points. These traps are commonly baited with multi-lure blends of pheromones and host volatiles. In this study, we tested this trapping protocol in areas surrounding eight entry points located in Europe and North America to determine: i) the relative performance of black-understory traps and green-canopy traps among the targeted taxa; and ii) whether the dissimilarity among communities of beetles collected by the understory vs. canopy traps was affected by taxon and amount of forest cover in the traps’ surroundings. A total of 96,963 individuals belonging to 358 species of wood-boring beetles were collected, including 21 non-native species. Black-understory multi-funnel traps were generally more efficient than green-canopy multi-funnel traps for detecting longhorn beetles and bark and ambrosia beetles, whereas the opposite trend was observed for jewel beetles. Differences between beetle communities caught in black-understory and green-canopy traps were mainly attributed to differences in species richness in jewel beetles, while both differences in species richness and species turnover contributed to the dissimilarity between communities of longhorn beetles and bark and ambrosia beetle. The difference in the number of jewel beetle species caught by the two trapping methodologies decreased with increasing forest cover, whereas species turnover increased when moving from an urban-dominated to a forest-dominated landscape. Overall, these results suggest that the simultaneous use of both black-understory and green-canopy multi-funnel traps can be considered a very efficient approach for generic surveillance of longhorn beetles, jewel beetles and bark and ambrosia beetles in both urban-dominated and forest-dominated areas surrounding entry points.

The aim of this study was to investigate the distribution, habitat preferences, host plants, and other aspects of the biology of longhorn beetles, as well as to identify threats to individual species and propose measures for their mitigation within the Biebrza Valley, particularly in Biebrza National Park (BbNP). The paper presents the results of field research conducted between 1982 and 2025 (with periodic breaks) in the Biebrza Valley (NE Poland). A total of 95 Cerambycidae species were recorded in the study area, representing 48% of the Polish longhorn beetle fauna. Ninety-two species were found within the BbNP boundaries, while three species were recorded from its buffer zone exclusively. The highest species richness was observed in the Middle Basin (83 species) and the Lower Basin (78 species), whereas the Upper Basin yielded 54 species. The most widely distributed species was Strangalia attenuata, recorded in sixteen UTM squares (10x10 km) and common in all three Biebrza basins. Stenurella nigra occurred in fourteen squares, while Grammoptera ruficornis, Rhagium mordax, and S. melanura were found in thirteen squares. Among the longhorn beetle species identified in the Biebrza Valley, eleven were classified as very rare and should be considered as "species of special concern". These included Cerambyx scopolii, Cyrtoclytus capra, Molorchus marmottani, Euracmaeops septentrionis, Leptura thoracica, Lepturalia nigripes, Aegomorphus obscurior, Exocentrus stierlini, Oberea euphorbiae, O. pupillata, and Saperda similis. Among all recorded cerambycid species, 76 were documented based on rearing from plant material (dead wood, twigs etc.) of various host plants. These comprised 24 plant species: 21 woody plants – trees and shrubs – and three herbaceous species. Broad-leaved trees and shrubs were dominant, as only two coniferous species (Pinus sylvestris and Picea abies) were confirmed as hosts. The highest number of species developed on Quercus robur (23), followed by P. sylvestris and P. abies (17), Salix spp. (12), Betula pendula and Alnus glutinosa (11 each). Other plant species hosted between one and nine Cerambycidae species. The species with the broadest host plant range were Rhagium mordax (eight species), Saperda scalaris (six), and both Anaesthetis Testacea and S. attenuata (five each). Noteworthy host associations included Clytus arietis on Frangula alnus, A. obscurior on A. glutinosa, and Exocentrus punctipennis on Q. robur. Two species found in the Biebrza Valley – C. scopolii and L. thoracica – are under partial protection in Poland. Several other species are included in the Polish Red List of Threatened and Endangered Animals, including L. nigripes, classified as Critically Endangered (CR), and L. thoracica as Vulnerable (VU). L. thoracica is also listed among the relic saproxylic beetles of Central Europe in the group of relics sensu stricto. No major threats have been identified for most saproxylic Cerambycidae species, with one exception. Comparison of recent data (2021–2025) with earlier records (1982–2011) has revealed concerning signs of a declining trend in the local population of A. obscurior. Threats were also identified for certain species developing in herbaceous plants. These include: − ecological succession (encroachment of woody vegetation in open areas leading to increased shading), accelerated by drainage and lowering of groundwater levels; a threat to, for example, Agapanthia intermedia, O. euphorbiae, and Phytoecia virgula; − lack of suitable host trees or shrubs for infestation, such as sun-exposed oaks (A. obscurior, C. scopolii), fire weakened/killed birches (L. nigripes), and old honeysuckle shrubs (O. pupillata); − disruption in the continuity and regeneration of host plants, potentially leading to the degradation of breeding habitats, especially for A. obscurior and, to a lesser extent, for C. scopolii, which can develop in other tree species; − small population size and isolation, which pose threats for species such as C. scopolii, L. nigripes, and O. euphorbiae; entomological poachin; − illegal collection of imagines or larvae with their host material (infested wood) of collector-attractive species. Documented cases include attempts at illegall collection of A. obscurior. For certain species (e.g. A. obscurior, C. scopolii, L. nigripes), active conservation measures are essential to preserve their populations. For most saproxylic species, passive conservation is highly effective if the protected area is sufficiently large. It is recommended that such protection be implemented in forests with a natural or near-natural character, or in those with the potential to become natural (e.g. parts of the Grzędy forest, the Las Trzyrzeczki tree stand, and the Kopciowe complex). The immediate acquisition of ecologically valuable areas (sites of rare Coleoptera occurrence) currently in private or military ownership within or around BbNP is strongly advised. Monitoring is proposed for one saproxylic beetle species (C. capra) and one species developing in herbaceous plants (O. euphorbiae).

Klingeman, William E., Youssef, Nadeer N., Oliver, Jason B., Basham, Joshua P. (2017): The longhorned beetles (Coleoptera: Cerambycidae) of Tennessee: distribution of species, seasonal adult activity, and new state records. Florida Entomologist 100 (2): 292, DOI: 10.1653/024.100.0226, URL: http://www.bioone.org/doi/10.1653/024.100.0226

Recent evidence has shown that the native Taiwan red pine (Pinus taiwanensis), once believed to be a resistant pine species, is subject to pinewood nematode Bursaphelenchus xylophulus attack. Because the pine sawyer, Monochamus alternates, has been confirmed as the major vector of the pinewood nematode, attempts were made to collect pine sawyers and other long-homed beetles in Taiwan red pine forests. A total of 28 adults and 42 larvae of 3 species of long-horned beetles, namely Acanthocinus gundaicnsis, M. alternatus, and Paraleprodera irzingeri, was found to be associated with dying and dead trees of Taiwan red pine. Based on this limited data, A. gundaiensis and P. itzingeri were more abundant than M. alternates in Taiwan red pine forests. Most significantly, 1 of the 16 newly emerged P. itzingeri was found to be carrying 7 Bursaphelenchus nematodes. This and the similarity of the feeding behavior of P. itzingeri and M. alternatus suggest that P. itzingeri may be a potential vector of the pinewood nematode in Taiwan red pine forests. This is the first report that Taiwan red pine is a host plant of M. alternatus and the endemic P. itzingeri and A. gundaiensis. The impact of these 3 species of long-horned beetles on Taiwan red pine must be understood and assessed before control measures directed at them, in an attempt to regulate the pinewood nematode in Taiwan red pine forests, can be implemented.

We analyzed effects of pitfall trap color on spider catches using four different pitfall trap colors (white, yellow, green, brown). For each color, we installed 17 pitfall traps at two grassland sites, respectively, and sampled 77 species from 6,202 individuals. Number of species showed no significant differences but Shannon- and Simpson-diversity were significantly higher in green and brown traps while number of individuals increased in white ones. Species inventories were not complete in the different pitfall trap colors but species accumulation increased significantly slower in white and brown traps. Trap color significantly affected hunting type with ground hunters being associated with bright and web-builders associated with dark colors. Attractiveness of different trap colors may arise due to differences in biological preconditions, albedo and microclimate which in turn can affect diversity and community structure of spiders. Trap color has a significant impact on spider catches and should be considered when planning surveys. We recommend the use of a combination of white and brown (or transparent) pitfall traps to gain complete and diverse species inventories in spiders.

Longhorn beetles (Cerambycidae) play a vital role in global ecosystems. Some of them contribute to nutrient cycling and pollination, while others, pose a threat to forestry production. Despite their ecological importance, there has been a lack of comprehensive analyses on the mitochondrial genomes of Cerambycidae beetles. In this study, we have conducted mitochondrial genome sequencing and annotation for four Cerambycidae beetles: Monochamus sutor, Monochamus guerryi, Monochamus galloprovincialis, and Monochamus latefasciatus. Our analysis revealed a high degree of conservation in these mitochondrial genomes, with rare gene rearrangements observed across the Cerambycidae family. Additionally, a notable bias towards AT content was identified, with most genes using ATN as the start codon and TAA as the stop codon. Except for trnS1, all tRNA genes showed typical cloverleaf secondary structures. Phylogenetic analysis using IQ-TREE and Phylobayes consistently produced congruent topologies. At the gene level analyses, our results highlighted the remarkable conservation of the COX1 gene. Furthermore, at the species level, we observed strong adaptability in the Spondylidinae and Lepturinae subfamilies. We also offer our insights into contentious aspects of the phylogeny. Overall, our research contributes to a deeper understanding of the phylogeny and evolution of Cerambycidae, laying the groundwork for future population genetic investigations.

In 2008 a few specimens of Anoplophora glabripennis (Asian Longhorn Beetle), were found for the first time in Denmark. The finding was connected with granite imported in wooden crates, although the wood packaging material was marked as outlined in ISPM no. 15. Activities on tracing back and official actions are described. A survey was performed to detect establishment of any further A. glabripennis having possibly escaped the crates. An information campaign for public awareness and for importers of granite was organised. Finally lessons learned are described.

The efficacy of various combinations of pheromones and plant volatile lures for detection of longhorn beetles (Coleoptera: Cerambycidae) in traps was tested in field bioassays in a mixed coniferous-deciduous forest near Vladivostok in the Russian Far East in 2009 and 2010. Traps detected 30 species (490 specimens) in 2009 and 23 species (182 specimens) in 2010. Overall, 38 longhorn beetle species were detected, with 15 species common to both years. Species composition differed among lure treatments, but the number of species detected with any single lure did not vary significantly among lures (12-16 species per lure in 2009; 3-10 species per lure in 2010). Type of lure significantly affected mean catch per trap of five species in 2009 and 2010. For these same species, lure type also significantly affected the efficacy of detection, i.e., the proportion of traps that captured at least one specimen of a given species. The combination of racemic E-fuscumol and spruce blend (a blend of five monoterpenes) positively affected mean catch of Tetropium castaneum (L.). Racemic 3-hydroxyhexan-2-one (K6), alone or combined with ethanol, increased mean catch of Anaglyptus colobotheoides Bates. The combination of K6 and ethanol increased mean catch of Phymatodes testaceus (L.), and the combination of racemic 3-hydroxyoctan-2-one and ethanol increased mean catch of Molorchus minor (L.). Use of longhorn beetle pheromone lures in trapping surveys increases the mean catch and probability of detecting certain species of Cerambycidae, including those that may be exotic and potentially invasive. Sample-based rarefaction indicated that eight traps per site were insufficient to detect all of the longhorn species potentially attracted by any individual lure treatment, i.e., species accumulation curves failed to reach an asymptote in most cases.

Longhorn beetles (Coleoptera: Cerambycidae) have an important function in the ecosystem, i.e. bioindicators, saproxylic, pollinators, and as food of other organisms. Land cover changes due to land use can disrupt the natural balance of the ecosystem, which can result in a decrease of cerambycid diversity. Cerambycid species diversity was evaluated in four land types, i.e. jungle-rubber, rubber plantations, oil palm plantations, and felled jungle-rubber. Collections of cerambycid beetles were conducted by using artocarpus trap, made by freshly cut Artocarpus heterophyllus branches. Collections of beetles were made on day 4th, 7th, 10th, 13th, and 16th after the traps were set up. In the four land-use types in Jambi province, we collected 72 species including 34 morphospecies of cerambycids, consisting of 42 species from the jungle-rubber, 39 species from rubber plantations, 16 species from oil palm plantations, and 28 species from felled jungle-rubber. Cerambycid diversity was highest in jungle-rubber (H'=3.23), followed by rubber plantation (H'=2.67), felled jungle-rubber (H'=2.38), and oil palm plantations (H'=2.01). Highest similarities of cerambycid communities occurred in the rubber plantation–felled jungle-rubber (51.2), followed by jungle-rubber–rubber plantation (50.0), rubber plantations–oil palm plantations (43.5), oil palm plantation–felled jungle-rubber (42.4), jungle-rubber–oil palm plantations (35.3), and jungle-rubber–felled jungle rubber (34.8). The number of cerambycid species and individuals collected was highest on day 7th.

Although pan traps are an established method for sampling bees across a wide range of habitats and geographical regions, uncertainty persists as to how pan-trap characteristics influence sampling results. We investigated the effect of pan-trap diameter (23 cm versus 12 cm), interacting with trap colour, on sampled bee communities and bycatch in wildflower strips within agricultural landscapes in Germany, using fluorescent blue, white and yellow pan traps. Based on 1147 collected bee individuals identified on a species level (69 species), we observed interacting effects of pan trap colour and size on the number of sampled bee individuals and species. Large pan traps collected significantly more bee individuals (white and yellow pan traps) and species (all colours) than small pan traps. Large pan traps also collected significantly more bycatch biomass than small pan traps, irrespectively of pan trap colour. The estimated number of sampled species based on the same number of sampled individuals (individual-based rarefaction) was higher for larger pan traps than for smaller pan traps at all sampling sites. Implications for insect conservation: using larger pan traps for sampling bees increases trap efficacy (absolute numbers of sampled individuals and species) and efficiency (sampled species per sampled individuals), but larger traps also capture more bycatch biomass. Particularly in long-term monitoring schemes, we encourage a limitation of this potential impact on the non-target insect fauna by employing methodological refinements. The option to use more small traps per site versus fewer large traps remains to be explored.

The Japanese beetle (JB) Popillia japonica (Coleoptera: Scarabaeidae) has been a significant invasive pest for over a century in North America. Several studies have reported that plants under direct sunlight are preferred and trap colour affects the number of beetles captured, indicating that visual stimuli influence JB behaviour. Despite this, the influence of visual cues on trap efficiency remains poorly understood, and its visual system has not been characterised. To address this knowledge gap, we conducted a field trial using panels to manipulate sun exposure of traps to test the effect of sunlight intensity on JB trap performance. Our results indicate that JB flight activity is reduced under lower sunlight conditions and that visual cues influence trap performance. Fully shaded traps consistently captured fewer beetles when cloud cover was below 85%. To better understand JB colour perception, we investigated its genome for visual opsin genes and analysed its photoreceptor sensitivity with an electroretinogram. We found evidence for a UV‐green dichromatic visual system, lacking the orange‐sensitive photoreceptor found in some Coleoptera. This may explain inconsistencies in trap colour preference reported in the literature and indicates that JB may not have been able to differentiate some of the colour treatments tested in published studies. To optimise JB trap capture, future studies should evaluate UV‐reflecting traps, control for spectral reflectance intensity, and investigate whether JB avoids low‐light conditions due to environmental risks or visual limitations.

The male of Adesmus murutinga Martins & Galileo, 2004 is described for the first time, an updated key to Colombian species of the genus is presented, and three species of longhorned beetles are reported for the first time for Colombia. The specific localities in Colombia of Miriclytus quadrifasciatus (Chevrolat, 1862) and Oedudes spectabilis (Drury, 1782) are reported.