Efficacy of Fluon conditioning for capturing cerambycid beetles in different trap designs and persistence on panel traps over time

Fluon PTFE is a fluoropolymer dispersion applied as a surface conditioner to cross-vane panel traps to enhance trap efficiency for cerambycid beetles. We describe the results of three experiments to further optimize cerambycid traps of different designs and to test the effect of Fluon over time. We tested Fluon with Lindgren funnel and panel traps fitted with either wet or dry collection cups on catches of cerambycid beetles and how the effect of Fluon on panel traps persisted. Fluon-treated funnel traps with wet collection cups captured approximately 6x more beetles than the untreated funnel traps with wet collection cups. Untreated funnel traps with dry collection cups did not capture any beetles; however, Fluon-treated funnel traps with dry collection cups captured an average of four beetles per trap. Fluon-treated panel traps with wet collection cups captured approximately 9x more beetles than untreated panel traps with wet collection cups. Fluon-treated panel traps with dry collection cups captured approximately 11x more beetles than untreated panel traps with dry collection cups. The effect of Fluon on capturing cerambycid beetles did not decline after use in one or two field seasons. There was no significant difference in the number of beetles captured in freshly treated panel traps compared with traps that had been used for 1 or 2 yr. Fluon-treated traps captured nine species that were not captured in untreated traps. Conditioning both Lindgren funnel and panel traps with Fluon enhances the efficacy and sensitivity of traps deployed to detect exotic cerambycid species, or for monitoring threatened species at low population densities.     

Differences in endemic insect assemblages among vegetation types on a small island of the oceanic Ogasawara Islands

Natural vegetation is often replaced by invasive alien plants on isolated oceanic islands. To determine how invasive alien plants affect insect diversity, we compared flying insects captured using Malaise traps among different vegetation types on a small island (Nishijima; 0.49 km²) in the oceanic Ogasawara (Bonin) Islands in the north‐western Pacific. The numbers of individuals and species, and the species composition of pollinators (bees), predators (wasps) and wood borers (cerambycid, mordellid and elaterid beetles) were compared among three vegetation types: Casuarina equisetifolia (an invasive alien tree) forest, natural forest and natural grassland (forest edge), during two seasons (June and October–November 2005). In traps, 80.0, 66.7, 87.5, 85.7 and 100.0% of bee, wasp, cerambycid, mordellid and elaterid beetle species, respectively, were endemic to the Ogasawara Islands. Grassland had the highest wasp and bee species richness, whereas natural forest had the highest species richness of wood‐boring beetles. The C. equisetifolia forest had the poorest species richness for most insect groups (except mordellid beetles). More individuals of most insect groups (except bees) were captured in June than in October–November. More individual bees and wasps were captured in grassland than in forests, whereas more individual mordellid and elaterid beetles were captured in forests than in grassland. The number of cerambycid individuals did not differ among vegetation types. Redundancy analysis suggested that most insect species preferred natural forest or grassland to alien forest. Therefore, further invasion of natural grassland and forest by the alien tree C. equisetifolia may negatively affect the endemic insect fauna of Nishijima.     

Considering species richness and rarity when selecting optimal survey traps: comparisons of semiochemical baited flight intercept traps for Cerambycidae in eastern North America

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Effects of habitat type and trap placement on captures of bark (Coleoptera: Scolytidae) and longhorned (Coleoptera: Cerambycidae) beetles in semiochemical-baited traps

Two studies were conducted to determine the effect of habitat selection and trap placement on catches of Scolytidae and Cerambycidae (Coleoptera) in northeastern U.S. forests. In a nonreplicated case study, four habitat types--closed canopy hardwood stand, closed canopy conifer stand, a low-intensity thinned Pinus strobus L. stand, and a high-intensity thinned P. strobus stand--were surveyed using alpha-pinene, ethanol, ipsenol, ipsdienol, and lanierone. Average trap catches, species richness, and the number of unique species captured were all highest in at least one of the thinned habitats. A second experiment that was replicated evaluated the placement of traps in relation to habitat patches. Semiochemical-baited traps (alpha-pinene and ethanol) were placed under a closed canopy forest, along an edge, and in a clearing and tested for effects on Scolytidae and Cerambycidae trap catches. Abundance and species richness were generally higher in the closed canopy and edge placements compared with traps in the open area. The highest number of unique species were captured in the edge and clearing.     

Beetle responses to artificial gaps in an oceanic island forest: implications for invasive tree management to conserve endemic species diversity

Natural forests are often replaced by invasive alien trees on isolated oceanic islands. Adequate eradication of invasive trees should be conducted with the goal of biodiversity conservation, because islands support many endemic organisms that depend on native forests. An invasive alien tree, Bischofia javanica Blume (Euphorbiaceae), has invaded and replaced natural forests on the oceanic Ogasawara (Bonin) Islands, Japan, in the northwestern Pacific Ocean. To determine how the removal of B. javanica trees affects insect diversity, we examined flying beetles captured using Malaise traps in B. javanica forests on Hahajima. The abundance, species density, and species composition of wood-boring beetles (Coleoptera: Cerambycidae, Elateridae, Mordellidae, and Scolytidae) were compared between closed-canopy sites and gaps created by girdling B. javanica trees in alien forests during two seasons (June–July and October–November 2005). Of the collected beetles, 75.8, 87.5, 90.0, and 0.0% of cerambycid, elaterid, mordellid, and scolytid beetle species, respectively, were endemic to the Ogasawara Islands. More cerambycid, elaterid, and mordellid individuals were captured in June–July than in October–November; the number of scolytid individuals did not differ between seasons. More cerambycid, elaterid, and scolytid individuals were captured in artificial gaps than on the closed-canopy forest floor. Although fewer mordellid individuals were captured in gaps, more endemic mordellids were captured in gaps. More cerambycid and scolytid species were captured in artificial gaps than in closed-canopy areas. The positive responses of beetles to artificial gaps suggest that the removal of B. javanica increases beetle diversity and the abundance of endemic beetles.     

Convergence in Arthropod Assemblages with Various Restoration Approaches for Canadian Deciduous Forests

Silvicultural practices are traditionally aimed at increasing forest profits; however, recent approaches to forest conservation have broadened to include nature-based silviculture for regenerating forests. In southern Ontario (Canada), originally dominated by deciduous forests, conifer plantations were established on abandoned agricultural sites. Currently, there is an increasing interest to convert these conifer stands to a state that mimics the original deciduous forest. We investigated arthropod abundance, species richness of carabid beetles, and abundance of arthropod assemblages (trophic and prey groups) under five silvicultural treatments conducted to regenerate deciduous forests (the natural forest type) from the old conifer plantations. The treatments included: (1) uniform canopy removal; (2) uniform canopy removal and understory removal; (3) group canopy removal; (4) group canopy removal and understory removal; and (5) untreated control plots (relatively pure red pine). Insects were sampled annually using sweepnets and pitfall traps. Results revealed treatment effects on the abundance of Coleoptera, Heteroptera, herbivores, and small arthropods (<3 mm) caught in sweepnet samples, where plots subjected to group shelterwood removal and understory removal supported higher abundances than the control plots. There was no treatment effect on the abundance of other arthropod groups or on the species richness and abundance of carabid beetles. The silvicultural treatments used to encourage natural regeneration did not seem to affect arthropod food availability for insectivorous vertebrates. Thus, the type of silvicultural strategy used to convert pine plantations to a stage that mimics the natural deciduous forests had little overall impact on arthropods.     

Small off-shore islands can serve as important refuges for endemic beetle conservation

Although large islands generally support a richer insect fauna than small islands, many large islands, which are more often inhabited, have lost numerous species because of human activities and introduced organisms. To clarify the consequences of endemic insect conservation on small islands near inhabited islands, we compared the species richness, abundance, and composition of two beetle groups (Coleoptera: Cerambycidae and Mordellidae) captured using Malaise traps among three islands (Chichijima, 24.0 km²; Anijima, 7.85 km²; Nishijima, 0.49 km²) in the oceanic Ogasawara (Bonin) Island group in the northwestern Pacific during June–July 2006 and 2007. Chichijima, the largest island, is inhabited, while Anijima and Nishijima are not. The numbers of cerambycid and mordellid species previously recorded were positively correlated with island area. However, the total numbers of cerambycid and mordellid species we captured in Malaise traps were not correlated with island area because we were unable to collect many species previously documented on Chichijima. The numbers of cerambycid and mordellid species per trap did not differ significantly among islands and years, although the deviance was well explained by the island variable. We captured greater numbers of cerambycid and mordellid individuals on Chichijima than on Anijima and Nishijima, and the numbers of cerambycid and mordellid individuals per trap significantly differed among islands and between years. Redundancy analysis (RDA) showed that the species composition of cerambycids and mordellids differed among the three islands. Whereas endangered species were rarely captured on Chichijima, alien or non-endemic species were frequently collected. Cerambycid and mordellid beetles on Chichijima may have been deleteriously affected by recent forest disturbance and introduced organisms. Therefore, conserving insect fauna on uninhabited island “refugia” is important for preserving the insect diversity of the Ogasawara Islands.     

宁夏黄土丘陵区不同生态恢复生境地表甲虫多样性

为了解宁夏黄土丘陵区不同生境地表甲虫群落多样性变化规律及与环境因子的关系, 并探讨不同生态恢复措施对维持地表甲虫群落多样性的影响, 2013年7-8月, 作者利用陷阱法调查了该区6种生境内的地表甲虫群落多样性。结果表明: 灌草混交林地、乔灌混交林地、生态薪炭林地中地表甲虫物种丰富度和个体数量均较高, 天然封育草地、生态经济林地和水平农田中物种丰富度较低, 生态经济林地和水平农田中甲虫个体数量显著高于天然封育草地。不同生境间, 灌草混交林地、乔灌混交林地与生态薪炭林地之间、生态经济林地与水平农田之间甲虫群落组成相似性较高。多元回归分析表明, 草本层生物量、灌木层盖度及土壤含水量是影响甲虫物种丰富度的决定因素, 林冠层盖度和枯落物厚度是决定地表甲虫个体数量的重要因素。CCA分析表明, 枯落物盖度、枯落物厚度、林冠层盖度及草本层盖度是影响地表甲虫群落组成的重要环境因子。研究表明, 灌草混交林地为地表甲虫群落多样性维持较好的生境类型, 是宁夏黄土丘陵区典型生态恢复的最优模式。     

A comparison of diversity and species composition of ground beetles (Coleoptera: Carabidae) between conifer plantations and regenerating forests in Korea

Ground beetles were collected by pitfall trapping to compare their species richness between conifer plantations (14 sites) and regenerating forests (14 sites) and among forest ages and to examine how different functional groups responded to forest type, forest age, patch size, elevation, and geographic location in terms of abundance and richness. Ground beetles were collected from middle August to late October, 2008. A total of 34 species were identified from 3,156 collected ground beetles. Individual-based rarefaction curves showed greater species richness in regenerating forests, especially in 40–50-year-old forests, than in conifer plantations. Stepwise multiple regression analysis showed that patch size and elevation were major predictors of species richness and/or abundance of forest specialists, brachypterous species, and large- and medium-bodied species. A multivariate regression tree indicated that patch size and elevation were major predictors of assemblage structure. Although our results suggest that maintaining forest areas adjacent to agricultural landscapes may be essential to preserve ground beetle assemblages irrespective of forest types, further study is necessary to clarify the effects of habitat quality and amount on ground beetles in forests.     

Efficiency of a Rapid Assessment of the Diversity of Ground Beetles and Ants, in Natural and Disturbed Habitats of the Nahuel Huapi Region (NW Patagonia, Argentina)

We use sample-based rarefaction curves to evaluate the efficiency of a rapid species richness assay of ground beetles and ants captured in pitfall traps in the Nahuel Huapi National Park (NW Patagonia, Argentina). We ask whether ant species richness patterns show some concordance with those of beetles, and use several extrapolation indices for estimating the expected number of species at a regional scale. A total of 342 pitfall traps were spread in groups, at an intensity of 9 traps/100 m², with two collection stations, at each of 19 sites representative of burned and unburned habitats in the forest, scrub and steppe, along a west-to-east transect of 63 km long. The high regional habitat heterogeneity along the west-to-east gradient is paralleled by a turnover of beetle and ant species, although different families of Coleoptera show idiosyncratic responses across habitat types. Spatial stratification of sampling over three major habitats along with the inclusion of burned and unburned environments may improve sampling efficiency. The observed and extrapolated species richness suggests that we captured a high proportion of the total number of species of beetles and ants known for the region. However, trends in species richness of ants may not indicate similar trends in beetles. Ants and beetles cannot be used as surrogate taxa for the analysis of species richness patterns. Instead, both taxa should be considered as focal as they may offer complementary information for the analysis of the effect of disturbance and regional habitat heterogeneity on species diversity patterns at a regional scale.     

Beetle diversity in a matrix of old-growth boreal forest: influence of habitat heterogeneity at multiple scales

The relative contribution of compositional and structural heterogeneity on biodiversity is currently ambiguous because field studies generally integrate these two sources of habitat heterogeneity into a single index. We established the relationship between species richness of ground-dwelling and flying beetles and compositional and structural attributes of forest heterogeneity. The relationship was evaluated at two spatial scales: the scale of forest stand, corresponding to an 11.3  m radius, and the scale of landscape, corresponding to either a 400 or 800  m radius. Seventy stands were sampled in the matrix of old-growth boreal forest of the North Shore region of Québec, Canada, during the summers of 2004 and 2005. A total of 133 ground-dwelling beetle species (range: 4–42 species per site) were captured in the pitfall traps and 251 flying species (range 16–58 species per site) in flight-interception traps. We found that the most relevant type of heterogeneity to explain variations in species richness and the significance of landscape scale information varied between groups of beetles. Compositional heterogeneity (i.e. the number of species of forest trees and shrubs) at the stand scale best predicted species richness in ground-dwelling beetles. On the other hand, it was the combined influence of structural and compositional habitat heterogeneity at stand and landscape scales that best explained richness patterns in flying beetles. Our study outlines the significance of considering multiple types and spatial scales of habitat heterogeneity when describing patterns of species richness.     

The effects of rainforest canopy loss on arboreal dung beetles in Borneo: implications for the measurement of biodiversity in derived tropical ecosystems

We examine the effect of selective timber extraction, and corresponding forest canopy loss, on arboreal dung beetles in the tropical rainforests of Sabah, Malaysian Borneo. Changes in vertical distribution of beetles are measured through differences in the abundance of beetles in ground-based pitfall traps in primary, logged and plantation forest. Previous research has demonstrated that arboreal dung beetles are not generally collected in pitfall traps in primary forest, but are present in large numbers above the ground in canopy vegetation: the presence of arboreal beetles in pitfalls in areas of reduced or modified canopy cover may therefore reflect a response to the absence or modification of their usual habitat, and the proliferation of these beetles nearer to the ground. In this paper, statistically significant differences are found in the abundance of beetles in ground pitfall traps from logged forest compared to primary forest. Results show that virtually no arboreal dung beetles are recorded in primary forest traps, with an increased abundance of arboreal dung beetles in traps from logged and plantation forest, with 1.72% of the total number of arboreal beetles recorded from primary forest, 22.32% from logged forest, and 75.96% from plantation forest. The presence of arboreal dung beetles in plantations demonstrates that arboreal dung beetles can survive outside their normal habitat, and we relate these observations to adaptations to upper rainforest canopy conditions, and proliferation of these microclimatic conditions in man-made habitats. Results are also discussed in terms of their relevance to the measurement of species richness and diversity in logged and other derived ecosystems, where mixing of the ground-based and arboreal faunas occurs.     

Evaluation of window flight traps for effectiveness at monitoring dead wood-associated beetles: the effect of ethanol lure under contrasting environmental conditions

1 Subsequent to the diversity of saproxylic beetles being proposed as a management tool in forestry, more explicit knowledge about the efficiency and selective properties of beetle sampling methods is needed.
2 We compared saproxylic beetle assemblages caught by alcohol-baited or unbaited window traps in different forest contexts. Considering that trap attractiveness depends on kairomone concentrations, we appraised whether the trap efficiency was influenced by trap environment (openness and local supply of fresh dead wood).
3 Saproxylic beetles were sampled using 48 cross-vane window flight traps, arranged in paired designs (alcohol-baited/unbaited), in eight ancient and eight recent gaps (open stands), and eight closed-canopy control stands in an upland beech forest in the French Pyrenees.
4 Baited traps were more efficient than unbaited traps in terms of abundance and richness in our deciduous forests. The ethanol lure did not have any repellent effect on the individual response of saproxylic taxa.
5 The influence of local environmental conditions on trap attractiveness was observed. Openness had a significant moderate effect on species richness. Trap attractiveness was slightly reduced in the alcohol-saturated environment of recent gaps probably due to a disruption by local fresh dead-wood concentrations of the kairomonal response of saproxylic beetles to baited traps ('alcohol disruption').
6 Because the ethanol lure enhanced the probability of species detection, it may be useful in early-warning surveillance, monitoring and control of wood borers, despite slight influences of local conditions on baited trap efficiency.     

Adults of the cerambycid beetle Megacyllene caryae use both olfactory and visual information to locate mates

Many species of beetles in the family Cerambycidae use volatile pheromones to facilitate the location of mates. Visual cues may also influence the location of mates, as the adults of many species of cerambycids are often brightly patterned and diurnal. Theory predicts that combining signals or cues of different modalities (e.g., chemical, visual) to transmit information will increase the likelihood of an organism responding to this information, compared to when the signal or cue is presented alone. Here, we test the hypothesis that attraction of adults of the cerambycid beetle Megacyllene caryae (Gahan) (Coleoptera: Cerambycidae, Clytini) to their pheromones will be increased when visual cues are present. Consistent with that hypothesis, the number of beetles caught by traps baited with pheromones was increased 3.4‐fold when a dead adult beetle of that species was attached to the trap, relative to those with just pheromone alone. Capture of M. caryae in our study was also influenced by the position of traps within forest stands, with traps at 100 m within stands catching 2.5× as many beetles as traps at the forest edge. These findings suggest that vision and visual cues play an important role in the location of mates by cerambycid beetles and warrant further research. Also, the inclusion of visual cues on traps may enhance the efficacy of trapping cerambycid beetles, such as the detection of species that are non‐native and potentially invasive, or when monitoring species that are native and of conservation concern.     

Effects of fruit‐baited trap height on flower and leaf chafer scarab beetles sampling in Amazon rainforest

There is no standardization of ideal trap installation height for an accurate sampling of flower and leaf chafer scarab beetles in the rainforest canopy. This limits the comparison among different studies on the ecology as well as systematic collecting of this beetle group. Here, we sampled flower and leaf chafer beetles using fruit‐baited traps installed at different heights (1.5, 4.5, 7.5 and 10.5 m) in the Brazilian Amazon rainforest with the following proposals: (i) we tested whether there are effects of trap installation height on the abundance, species richness and biomass of these beetles; and (ii) we tested whether there is a difference in the species composition between each trap height. From January to April 2017, we sampled flower and leaf chafer beetles by using traps baited with a banana and sugarcane juice mixture in Amazon rainforest fragments in Porto Velho, Rondônia, Brazil. The abundance, species richness and biomass of flower chafer beetles (Cetoniinae) were higher in traps installed at 10.5 m. For leaf chafer beetles (Rutelinae), we found the higher species richness and abundance at 4.5, 7.5 and 10.5 m, but the biomass of these insects did not differ among the different heights. Only the community composition of flower chafer beetles differed among the different trap installation heights. Our results showed that flower chafer beetles demonstrate a preference for foraging for resources at greater heights in the Amazon rainforest. Thus, to collect cetoniines from tropical forests, the recommended manner is to install the traps in the forest canopy.     

The contribution of cacao agroforests to the conservation of lower canopy ant and beetle diversity in Indonesia

The ongoing destruction of tropical rainforests has increased the interest in the potential value of tropical agroforests for the conservation of biodiversity. Traditional, shaded agroforests may support high levels of biodiversity, for some groups even approaching that of undisturbed tropical forests. However, it is unclear to what extent forest fauna is represented in this diversity and how management affects forest fauna in agroforests. We studied lower canopy ant and beetle fauna in cacao agroforests and forests in Central Sulawesi, Indonesia, a region dominated by cacao agroforestry. We compared ant and beetle species richness and composition in forests and cacao agroforests and studied the impact of two aspects of management intensification (the decrease in shade tree diversity and in shade canopy cover) on ant and beetle diversity. The agroforests had three types of shade that represented a decrease in tree diversity (high, intermediate and low diversity). Species richness of ants and beetles in the canopies of the cacao trees was similar to that found in lower canopy forest trees. However, the composition of ant and beetle communities differed greatly between the agroforest and forest sites. Forest beetles suffered profoundly from the conversion to agroforests: only 12.5% of the beetle species recorded in the forest sites were also found in the agroforests and those species made up only 5% of all beetles collected from cacao. In contrast, forest ants were well represented in agroforests, with 75% of all species encountered in the forest sites also occurring on cacao. The reduction of shade tree diversity had no negative effect on ants and beetles on cacao trees. Beetle abundances and non-forest ant species richness even increased with decreasing shade tree diversity. Thinning of the shade canopy was related to a decrease in richness of forest ant species on cacao trees but not of beetles. The contrasting responses of ants and beetles to shade tree management emphasize that conservation plans that focus on one taxonomic group may not work for others. Overall ant and beetle diversity can remain high in shaded agroforests but the conservation of forest ants and beetles in particular depends primarily on the protection of natural forests, which for forest ants can be complemented by the conservation of adjacent shaded cacao agroforests.     

Selected beetle assemblages captured in pitfall traps baited with deer dung or meat in balsam fir and sugar maple forests of central Quebec

Vertebrate dung and carrion are rich and strongly attractive resources for numerous beetles that are often closely linked to them. The presence and abundance of beetles exploiting such resources are influenced by various ecological factors including climate and forest cover vegetation. We studied selected assemblages of coprophilous and necrophagous beetles in Quebec along a 115-km north-south transect in three balsam fir (Abies balsamea (L.) Miller) forest sites and in a fourth forest site dominated by sugar maple (Acer saccharum Marshall), close to the southern fir site. Beetle abundance was estimated using a sampling design comprising replicated pitfall traps baited with red deer meat or dung in each site. A total of 8,511 beetles were caught and identified to family level, 95.7% of which belonged to families with known coprophilous or necrophagous behavior. Meat-baited pitfall traps caught nearly 15 times as many beetles as dung-baited traps. All Histeridae, Hydrophilidae, Scarabaeidae, and Silphidae were identified to species to examine specific diversity variation among sites. For the beetles caught in the meat-baited traps (majority of captures), decreases in abundance and species richness were observed from south to north along the fir forest transect, with evidence of decreasing specific diversity as measured by the Shannon index of diversity. Strong differences in species assemblages were also observed between the southern maple and fir forest sites. The Silphidae and Histeridae were more abundant in the maple forest, whereas the Hydrophilidae and Ptilidae were more abundant in the fir forest.     

Evaluation of double-decker traps for emerald ash borer (Coleoptera: Buprestidae)

Improved detection tools are needed for the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), an invasive forest insect from Asia that has killed millions of ash (Fraxinus spp.) trees in North America since its discovery in Michigan in 2002. We evaluated attraction of adult A. planipennis to artificial traps incorporating visual (e.g., height, color, silhouette) and olfactory cues (e.g., host volatiles) at field sites in Michigan. We developed a double-decker trap consisting of a 3-m-tall polyvinyl pipe with two purple prisms attached near the top. In 2006, we compared A. planipennis attraction to double-decker traps baited with various combinations of manuka oil (containing sesquiterpenes present in ash bark), a blend of four ash leaf volatiles (leaf blend), and a rough texture to simulate bark. Significantly more A. planipennis were captured per trap when traps without the rough texture were baited with the leaf blend and manuka oil lures than on traps with texture and manuka oil but no leaf blend. In 2007, we also tested single prism traps set 1.5 m above ground and tower traps, similar to double-decker traps but 6 m tall. Double-decker traps baited with the leaf blend and manuka oil, with or without the addition of ash leaf and bark extracts, captured significantly more A. planipennis than similarly baited single prism traps, tower traps, or unbaited double-decker traps. A baited double-decker trap captured A. planipennis at a field site that was not previously known to be infested, representing the first detection event using artificial traps and lures. In 2008, we compared purple or green double-decker traps, single prisms suspended 3-5 m above ground in the ash canopy (canopy traps), and large flat purple traps (billboard traps). Significantly more A. planipennis were captured in purple versus green traps, baited traps versus unbaited traps, and double-decker versus canopy traps, whereas billboard traps were intermediate. At sites with very low A. planipennis densities, more A. planipennis were captured on baited double-decker traps than on other traps and a higher percentage of the baited double-decker traps captured beetles than any other trap design. In all 3 yr, peak A. planipennis activity occurred during late June to mid-July, corresponding to 800-1200 growing degree-days base 10 degrees C (DD10). Nearly all (95%) beetles were captured by the end of July at approximately 1400 DD10.     

Aspen (<Emphasis Type="Italic">Populus tremuloides</Emphasis>) stands and their contribution to plant diversity in a semiarid coniferous landscape

We conducted a field study to determine the relative contributions of aspen (Populus tremuloides), meadow, and conifer communities to local and landscape-level plant species diversity in the Sierra Nevada and southern Cascade Range, northeastern California, USA. We surveyed plant assemblages at 30 sites that included adjacent aspen, conifer, and meadow communities across a 10,000-km² region. We statistically investigated patterns in local and landscape-scale plant diversity within and among the three vegetation types. Summing across sites, aspen stands supported more plant species overall and more unique plant species than either meadow or conifer communities. Local richness and diversity did not differ between aspen and meadow plots; conifer forest plots were significantly lower in both measures. Heterogeneity in species composition was higher for aspen forest than for meadows or conifer forest, both within sites and between sites. Plant communities in aspen stands shared less than 25% of their species with adjacent vegetation in conifer and meadow plots. Within aspen forest, we found a negative relationship between total canopy cover and plant diversity. Our results strongly support the idea that plant communities of aspen stands are compositionally distinct from adjacent meadows and conifer forest, and that aspen forests are a major contributor to plant species diversity in the study region. Current patterns of aspen stand succession to conifer forest on many sites in the semiarid western US are likely to reduce local and landscape-level plant species diversity, and may also have negative effects on other ecosystem functions and services provided by aspen forest.     

Blending synthetic pheromones of cerambycid beetles to develop trap lures that simultaneously attract multiple species

We evaluated attraction of cerambycid beetle species to blends of known cerambycid pheromones to determine whether such blends could be used as effective trap lures for detecting and monitoring multiple species simultaneously. Pheromone-baited traps captured 1,358 cerambycid beetles of which 1,101 (81.1%) belonged to three species in the subfamily Cerambycinae: Neoclytus acuminatus (F.), Neoclytus mucronatus (F.), and Xylotrechus colonus (F.). Beetles of these species were significantly attracted to synthetic blends that contained their pheromone components (isomers of 3-hydroxy-2-hexanone, 2,3-hexanediol, or both), despite the presence of pheromone components of different species, including other isomers of 2,3-hexanediol, (E/Z)-6,10-dimethyl-5,9-undecadien-2-yl acetate, and citral. In some cases, attraction was partially inhibited by the pheromone components of heterospecific species, whereas for N. acuminatus, attraction was completely inhibited when blends contained (2R*,3S*)-hexanediol, the racemic mixture of diastereomers of its pheromone, (2S,3S)-hexanediol. Among the remaining beetles captured were three species in the subfamily Lamiinae: Astyleiopus variegatus (Haldeman), Graphisurus fasciatus (Degeer), and Lepturges angulatus (LeConte). All three lamiine species were previously known to be attracted to (E/Z)-6,10-dimethyl-5,9-undecadien-2-yl acetate and were captured in significant numbers by blends containing that compound. Our results suggest that different types of cerambycid pheromones can be combined to create effective multispecies lures for use in surveillance programs that target exotic cerambycid species.