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Hisashi Kajimura - One of the best experts on this subject based on the ideXlab platform.
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Recent advances toward the sustainable management of invasive Xylosandrus ambrosia beetles
Journal of Pest Science, 2021Co-Authors: Antonio Gugliuzzo, James P. Egonyu, Jiri Hulcr, Louela A Castrillo, Peter H. W. Biedermann, Daniel Carrillo, Diego Gallego, Khalid Haddi, Hervé Jactel, Hisashi KajimuraAbstract:We provide an overview of both traditional and innovative control tools for management of three Xylosandrus ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), invasive species with a history of damage in forests, nurseries, orchards and urban areas. Xylosandrus compactus , X. crassiusculus and X. germanus are native to Asia, and currently established in several countries around the globe. Adult females bore galleries into the plant xylem inoculating mutualistic ambrosia fungi that serve as food source for the developing progeny. Tunneling activity results in chewed wood extrusion from entry holes, sap outflow, foliage wilting followed by canopy dieback, and branch and trunk necrosis. Maintaining plant health by reducing physiological stress is the first recommendation for long-term control. Baited traps, ethanol-treated bolts, trap logs and trap trees of selected species can be used to monitor Xylosandrus species. Conventional pest control methods are mostly ineffective against Xylosandrus beetles because of the pests’ broad host range and rapid spread. Due to challenges with conventional control, more innovative control approaches are being tested, such as the optimization of the push–pull strategy based on specific attractant and repellent combinations, or the use of insecticide-treated netting. Biological control based on the release of entomopathogenic and mycoparasitic fungi, as well as the use of antagonistic bacteria, has yielded promising results. However, these technologies still require validation in real field conditions. Overall, we suggest that management efforts should primarily focus on reducing plant stress and potentially be combined with a multi-faceted approach for controlling Xylosandrus damage.
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landscape scale genetic differentiation of a mycangial fungus associated with the ambrosia beetle Xylosandrus germanus blandford curculionidae scolytinae in japan
Ecology and Evolution, 2017Co-Authors: Masaaki Ito, Hisashi KajimuraAbstract:In this study, we examined the genetic structures of the ambrosia fungus isolated from mycangia of the scolytine beetle, Xylosandrus germanus to understand their co-evolutionary relationships. We analyzed datasets of three ambrosia fungus loci (18S rDNA, 28S rDNA, and the β-tubulin gene) and a X. germanus locus dataset (cytochrome c oxidase subunit 1 (COI) mitochondrial DNA). The ambrosia fungi were separated into three cultural morphptypes, and their haplotypes were distinguished by phylogenetic analysis on the basis of the three loci. The COI phylogenetic analysis revealed three distinct genetic lineages (clades A, B, and C) within X. germanus, each of which corresponded to specific ambrosia fungus cultural morphptypes. The fungal symbiont phylogeny was not concordant with that of the beetle. Our results suggest that X. germanus may be unable to exchange its mycangial fungi, but extraordinary horizontal transmission of symbiotic fungi between the beetle's lineages occurred at least once during the evolutionary history of this symbiosis.
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superinfection of five wolbachia in the alnus ambrosia beetle Xylosandrus germanus blandford coleoptera curuculionidae
Bulletin of Entomological Research, 2010Co-Authors: Yuuki Kawasaki, Masaaki Ito, K Miura, Hisashi KajimuraAbstract:Wolbachia bacteria are among the most common endosymbionts in insects. In Wolbachia research, the Wolbachia surface protein (wsp) gene has been used as a phylogenetic tool, but relationships inferred by single-locus analysis can be unreliable because of the extensive genome recombination among Wolbachia strains. Therefore, a multilocus sequence typing (MLST) method for Wolbachia, which relies upon a set of five conserved genes, is recommended. In this study, we examined whether the alnus ambrosia beetle, Xylosandrus germanus (Blandford), is infected with Wolbachia using wsp and MLST genes. Wolbachia was detected from all tested specimens of X. germanus (n=120) by wsp amplification. Five distinct sequences (i.e. five alleles) for wsp were found, and labeled as wXge1-5. MLST analysis and molecular phylogeny of concatenated sequences of MLST genes identified wXge3 and wXge5 as closely-related strains. The detection rate of wXge4 and wXge1 was 100% and 63.3%, respectively; wXge2, wXge3 and wXge5 were detected from less than 15% of specimens. We performed mitochondrial haplotype analyses that identified three genetic types of X. germanus, i.e. Clades A, B and C. Wsp alleles wXge1, wXge2 and wXge4 were detected in all clade A beetles; wXge2 allele was absent from Clades B and C. We concluded that (i) five wsp alleles were found from X. germanus, (ii) use of MLST genes, rather than the wsp gene, are more suited to construct Wolbachia phylogenies and (iii) wsp alleles wXge2 and wXge3/wXge5 would infect clade A and clade B/C of X. germanus, respectively.
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genetic structure of japanese populations of Xylosandrus brevis curculionidae scolytinae
Environmental Entomology, 2009Co-Authors: Masaaki Ito, Hisashi KajimuraAbstract:We examined the genetic structure of populations of an ambrosia beetle, Xylosandrus brevis (Eichhoff) (Curculionidae: Scolytinae), to understand its colonization dynamics. We collected specimens from 20 sites in Japan and studied the genetic structure of these populations using portions of the mitochondrial cytochrome oxidase I gene (COI). A phylogenetic analysis showed three distinct lineages (clades A, B, and C) within X. brevis. Clade A had 65 haplotypes from all the populations, except for populations from Nagano (Chiisagata-gun) and the Ryukyu Islands (Ishigaki), whereas clade B had 14 haplotypes from nine populations (Yamagata, Saitama, Shimo-Minochi-gun, Chiisagata-gun, Toyota, Watarai-gun, Wakayama, Tottori, and Kochi), and clade C had 6 haplotypes from the Ryukyu Islands (Ishigaki) population (and nowhere else). Nested clade phylogeographic analysis showed 65 clade A haplotypes and 14 clade B haplotypes geographically structured in two clades, respectively. A contact zone was identified in the Chubu and Tokai areas. Our results suggest that gene flow and individual movement of X. brevis between the Ryukyu Islands and the other three main islands of Japan has been rare, and X. brevis may be divided into two populations, eastern-central and northern-western, with little gene flow between the four areas of western Japan (Kinki, Chugoku, Shikoku, and Kyushu).
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Phylogeography of an ambrosia beetle, Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae: Scolytinae), in Japan
Applied Entomology and Zoology, 2009Co-Authors: Masaaki Ito, Hisashi KajimuraAbstract:We examined the genetic structure of populations of an ambrosia beetle, Xylosandrus crassiusculus. Specimens were collected from 22 sites in Japan and their genetic structure was studied using a portion of the mitochondrial cytochrome oxidase I gene. Phylogenetic analysis revealed three distinct lineages (clades A, B and C), each of which was divided into two subclades (A1, A2, B1, B2, C1 and C2). Subclade A1 had 17 haplotypes from Hokkaido, Honshu and Kyushu populations, subclade A2 5 haplotypes mainly from Shikoku populations, subclade B1 15 haplotypes from central and western Honshu and Amami populations, subclade B2 2 haplotypes only from Naha population, subclade C1 4 haplotypes from Amami and Naha populations, and subclade C2 5 haplotypes only from Ishigaki population. Analysis of molecular variance detected genetic differentiation among populations. The data imply that the genetic structure of Japanese populations of X. crassiusculus has been affected by the geological history of the Japanese islands, but that the mtDNA phylogeographic pattern is so complex that we could not infer any simple scenario of population history in X. crassiusculus.
Christopher M. Ranger - One of the best experts on this subject based on the ideXlab platform.
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semiochemical mediated host selection by Xylosandrus spp ambrosia beetles coleoptera curculionidae attacking horticultural tree crops a review of basic and applied science
Canadian Entomologist, 2021Co-Authors: Christopher M. Ranger, Matthew D. Ginzel, Karla M. Addesso, Michael Reding, Davide RassatiAbstract:Exotic ambrosia beetles (Curculionidae: Scolytinae) in the tribe Xyleborini include destructive pests of trees growing in horticultural cropping systems. Three species are especially problematic: Xylosandrus compactus (Eichhoff), Xylosandrus crassiusculus (Motschulsky), and Xylosandrus germanus (Blandford). Due to similarities in their host tree interactions, this mini-review focuses on these three species with the goal of describing their host-selection behaviour, characterising associated semiochemicals, and assessing how these interactions relate to their management. All three of these Xylosandrus spp. attack a broad range of trees and shrubs. Physiologically stressed trees are preferentially attacked by X. crassiusculus and X. germanus, but the influence of stress on host selection by X. compactus is less clear. Ethanol is emitted from weakened trees in response to a variety of stressors, and it represents an important attractant for all three species. Other host-derived compounds tested are inconsistent or inactive. Verbenone inhibits attraction to ethanol, but the effect is inconsistent and does not prevent attacks. Integrating repellents and attractants into a push–pull management strategy has been ineffective for reducing attacks but could be optimised further. Overall, maintaining host vigour and minimising stress-induced ethanol are keys for managing these insects, particularly X. crassiusculus and X. germanus.
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Origin of non-native Xylosandrus germanus, an invasive pest ambrosia beetle in Europe and North America
Journal of Pest Science, 2020Co-Authors: Marek Dzurenko, Christopher M. Ranger, Jiri Hulcr, Juraj Galko, Peter KaňuchAbstract:Xyleborine ambrosia beetles (Coleoptera: Scolytinae: Xyleborini) are among the most important and destructive pests in forests, tree nurseries and plantations worldwide. Their cryptic lifestyle, fungal mutualism, inbreeding and broad host range have predisposed them to become remarkably successful invaders and colonize novel habitats across the world. The black timber bark beetle, Xylosandrus germanus (Blandford), is native to East Asia, but now established in North America and Europe. It is an economically significant invasive pest in North American nurseries and orchards, and European forests. Managing and preventing the spread of exotic species such as X. germanus requires an understanding of invasion pathways and mechanisms associated with their source populations. In this study, we sequenced the mitochondrial gene COI and nuclear gene ArgK from six native and 24 non-native X. germanus populations to identify their origins. The genetic structure of X. germanus in non-native habitats is highly uniform and points to introductions from Honshu and/or Hokkaido, Japan. However, different haplotypes of the inferred Japanese source lineage, which dominate in North America and Europe today, together with temporal incidence of records of X. germanus indicate that these continents were invaded independently. While European populations were probably introduced only once prior to 1951, the genetic pattern of North American populations suggests that X. germanus was introduced several times.
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comparative morphology and distribution of antennal sensilla on Xylosandrus germanus and Xylosandrus crassiusculus coleoptera curculionidae scolytinae
Annals of The Entomological Society of America, 2016Co-Authors: Christopher M. Ranger, Michael E. Reding, Leona Horst, Jenny Barnett, Betsy Anderson, Charles R KrauseAbstract:The nonnative ambrosia beetles Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) are destructive pests of plants and trees growing in ornamental nurseries and tree fruit orchards. Perception of stress-induced volatiles plays an important role in aiding female X. germanus and X. crassiusculus in locating vulnerable hosts, while adult males of both species are flightless and not involved in host selection. Scanning electron microscopy was used to characterize the antennae of both species, which consisted of a scape, funicle, and club. Emphasis was placed on the type, structure, and distribution of sensilla associated with the antennal clubs of female and male X. germanus and X. crassiusculus . Sensilla observed on the anterior surface of the club for females and males of both species include one type of sensillum chaeticum (SC1), one type of sensillum trichodeum (ST1), and five types of sensilla basiconica (SB1–5). Sensilla are distributed in association with two sensory bands and/or a basal cluster. SB1, the most abundant sensilla type found on female and male clubs for both species, appears to be highly porous. No obvious sexual dimorphism was observed regarding sensilla type, but most types are more abundant on the antennal clubs of females compared with males for X. germanus and X. crassiusculus . Possible functions of the sensilla types are discussed based on morphology. These results provide an improved understanding of sensilla associated with X. germanus and X. crassiusculus that will aid electrophysiological investigations into their host selection behavior.
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RESEARCH ARTICLE Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees
2016Co-Authors: Christopher M. Ranger, Peter B. Schultz, Steven D. Frank, Juang H. Chong, E. RedingAbstract:Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and coloni-zation by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flower-ing dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus wer
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movement of Xylosandrus germanus coleoptera curculionidae in ornamental nurseries and surrounding habitats
Journal of Economic Entomology, 2015Co-Authors: Michael E. Reding, Jason B. Oliver, Christopher M. Ranger, Blair J Sampson, C T Werle, Peter B. SchultzAbstract:Some exotic ambrosia beetles are damaging pests in ornamental nurseries. Xylosandrus germanus (Blandford) is the most problematic ambrosia beetle in Ohio nurseries. Movement of X. germanus in nurseries has not been characterized, and knowledge is lacking on whether infestations originate from within nurseries or surrounding habitats. Flight activity of X. germanus was monitored in nurseries and adjacent wooded areas to determine the source of beetles infesting nurseries, and characterize their movement within nurseries. Ethanol-baited bottle traps were positioned within wooded areas adjacent to commercial nurseries and within nurseries at various distances from the nursery woodlot interface. Flight activity of overwintered X. germanus occurred in wooded areas adjacent to nurseries before occurrence within nurseries. There was a direct relationship between degree-days and the distance from woodlots when X. germanus were first found in traps in spring, with earlier captures closest to wooded areas and latest ones furthest away into the nursery. X. germanus appeared to move into nurseries from adjacent wooded areas, with numbers trapped within nurseries decreasing with distance away from wooded areas. Trees in the interior of nurseries would appear to be subjected to less attack pressure than trees near the nursery border. Intercepting beetles as they move into nurseries might be an effective strategy to reduce attack pressure on valuable trees.
Jiri Hulcr - One of the best experts on this subject based on the ideXlab platform.
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Recent advances toward the sustainable management of invasive Xylosandrus ambrosia beetles
Journal of Pest Science, 2021Co-Authors: Antonio Gugliuzzo, James P. Egonyu, Jiri Hulcr, Louela A Castrillo, Peter H. W. Biedermann, Daniel Carrillo, Diego Gallego, Khalid Haddi, Hervé Jactel, Hisashi KajimuraAbstract:We provide an overview of both traditional and innovative control tools for management of three Xylosandrus ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), invasive species with a history of damage in forests, nurseries, orchards and urban areas. Xylosandrus compactus , X. crassiusculus and X. germanus are native to Asia, and currently established in several countries around the globe. Adult females bore galleries into the plant xylem inoculating mutualistic ambrosia fungi that serve as food source for the developing progeny. Tunneling activity results in chewed wood extrusion from entry holes, sap outflow, foliage wilting followed by canopy dieback, and branch and trunk necrosis. Maintaining plant health by reducing physiological stress is the first recommendation for long-term control. Baited traps, ethanol-treated bolts, trap logs and trap trees of selected species can be used to monitor Xylosandrus species. Conventional pest control methods are mostly ineffective against Xylosandrus beetles because of the pests’ broad host range and rapid spread. Due to challenges with conventional control, more innovative control approaches are being tested, such as the optimization of the push–pull strategy based on specific attractant and repellent combinations, or the use of insecticide-treated netting. Biological control based on the release of entomopathogenic and mycoparasitic fungi, as well as the use of antagonistic bacteria, has yielded promising results. However, these technologies still require validation in real field conditions. Overall, we suggest that management efforts should primarily focus on reducing plant stress and potentially be combined with a multi-faceted approach for controlling Xylosandrus damage.
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Origin of non-native Xylosandrus germanus, an invasive pest ambrosia beetle in Europe and North America
Journal of Pest Science, 2020Co-Authors: Marek Dzurenko, Christopher M. Ranger, Jiri Hulcr, Juraj Galko, Peter KaňuchAbstract:Xyleborine ambrosia beetles (Coleoptera: Scolytinae: Xyleborini) are among the most important and destructive pests in forests, tree nurseries and plantations worldwide. Their cryptic lifestyle, fungal mutualism, inbreeding and broad host range have predisposed them to become remarkably successful invaders and colonize novel habitats across the world. The black timber bark beetle, Xylosandrus germanus (Blandford), is native to East Asia, but now established in North America and Europe. It is an economically significant invasive pest in North American nurseries and orchards, and European forests. Managing and preventing the spread of exotic species such as X. germanus requires an understanding of invasion pathways and mechanisms associated with their source populations. In this study, we sequenced the mitochondrial gene COI and nuclear gene ArgK from six native and 24 non-native X. germanus populations to identify their origins. The genetic structure of X. germanus in non-native habitats is highly uniform and points to introductions from Honshu and/or Hokkaido, Japan. However, different haplotypes of the inferred Japanese source lineage, which dominate in North America and Europe today, together with temporal incidence of records of X. germanus indicate that these continents were invaded independently. While European populations were probably introduced only once prior to 1951, the genetic pattern of North American populations suggests that X. germanus was introduced several times.
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plasticity of mycangia in Xylosandrus ambrosia beetles
Insect Science, 2019Co-Authors: Yongying Ruan, Edward L Stanley, James Skelton, Jiri HulcrAbstract:Insects that depend on microbial mutualists evolved a variety of organs to transport the microsymbionts while dispersing. The ontogeny and variability of such organs is rarely studied, and the microsymbiont's effects on the animal tissue development remain unknown in most cases. Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae or Platypodinae) and their mutualistic fungi are an ideal system to study the animal-fungus interactions. While the interspecific diversity of their fungus transport organ-mycangia-is well-known, their developmental plasticity has been poorly described. To determine the ontogeny of the mycangium and the influence of the symbiotic fungus on the tissue development, we dissected by hand or scanned with micro-CT the mycangia in various developmental stages in five Xylosandrus ambrosia beetle species that possess a large, mesonotal mycangium: Xylosandrus amputatus, Xylosandrus compactus, Xylosandrus crassiusculus, Xylosandrus discolor, and Xylosandrus germanus. We processed 181 beetle samples from the United States and China. All five species displayed three stages of the mycangium development: (1) young teneral adults had an empty, deflated and cryptic mycangium without fungal mass; (2) in fully mature adults during dispersal, the pro-mesonotal membrane was inflated, and most individuals developed a mycangium mostly filled with the symbiont, though size and symmetry varied; and (3) after successful establishment of their new galleries, most females discharged the bulk of the fungal inoculum and deflated the mycangium. Experimental aposymbiotic individuals demonstrated that the pronotal membrane invaginated independently of the presence of the fungus, but the fungus was required for inflation. Mycangia are more dynamic than previously thought, and their morphological changes correspond to the phases of the symbiosis. Importantly, studies of the fungal symbionts or plant pathogen transmission in ambrosia beetles need to consider which developmental stage to sample. We provide illustrations of the different stages, including microphotography of dissections and micro-CT scans.
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north american xyleborini north of mexico a review and key to genera and species coleoptera curculionidae scolytinae
ZooKeys, 2018Co-Authors: Demian Gomez, Robert J Rabaglia, Katherine E O Fairbanks, Jiri HulcrAbstract:: Bark and ambrosia beetles (Scolytinae) are the most successful group of invasive wood borers worldwide, and the most invasive among them are species in the tribe Xyleborini. This haplodiploid, highly inbred, fungus-farming group is represented by 30 non-native species in North America, of which at least five are serious pests. The few identification resources for Xyleborini that exist are becoming outdated due to new species arrivals and nomenclatural changes. Here we present a new comprehensive key to Xyleborini currently known from the continental United States. Compared to the previous key, the following species have been added to the North American fauna: Ambrosiodmus minor (Stebbing), Ambrosiophilus nodulosus (Eggers), Anisandrus maiche Kurentsov, Coptoborus pseudotenuis (Schedl), Cyclorhipidion fukiense (Eggers), Dryocoetoides reticulatus Atkinson, Dryoxylon onoharaense (Murayama), Euwallacea interjectus (Blandford), Xyleborinus andrewesi (Blandford), Xyleborinus artestriatus (Eichhoff), Xyleborinus octiesdentatus (Murayama), Xyleborus bispinatus Eichhoff, Xyleborus seriatus Blandford, Xyleborus spinulosus Blandford, and Xylosandrus amputatus (Blandford).
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cryptic genetic variation in an inbreeding and cosmopolitan pest Xylosandrus crassiusculus revealed using ddradseq
Ecology and Evolution, 2017Co-Authors: Caroline Storer, Bjarte H Jordal, Adam C Payton, Stuart F Mcdaniel, Jiri HulcrAbstract:Each year new exotic species are transported across the world through global commerce, causing considerable economic and ecological damage. An important component of managing invasion pathways is to identify source populations. Some of the most widespread exotic species are haplodiploid ambrosia beetles. The ability to mate with siblings (inbreed) and their transportable food source (symbiotic fungus) have enabled them to colonize most of the world and become pests of plant nurseries, lumber, and forests. One of the fastest spreading ambrosia beetles is Xylosandrus crassiusculus. In order to discover the source populations of this globally invasive species, track its movement around the world, and test biogeographical scenarios, we combined restriction site-associated DNA sequencing (RADseq) with comprehensive sampling across the species native and introduced range. From 1,365 genotyped SNP loci across 198 individuals, we determined that in its native range, X. crassiusculus is comprised of a population in Southeast Asia that includes mainland China, Thailand, and Taiwan, and a second island population in Japan. North America and Central America were colonized from the island populations, while Africa and Oceania were colonized from the mainland Asia, and Hawaii was colonized by both populations. Populations of X. crassiusculus in North America were genetically diverse and highly structured, suggesting (1) numerous, repeated introductions; (2) introduction of a large founding population; or (3) both scenarios with higher than expected outcrossing. X. crassiusculus, other wood-boring insects, and indeed many other pests with unusual genetic structure continue to spread around the world. We show that contemporary genetic methods offer a powerful tool for understanding and preventing pathways of future biosecurity threats.
Michael E. Reding - One of the best experts on this subject based on the ideXlab platform.
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comparative morphology and distribution of antennal sensilla on Xylosandrus germanus and Xylosandrus crassiusculus coleoptera curculionidae scolytinae
Annals of The Entomological Society of America, 2016Co-Authors: Christopher M. Ranger, Michael E. Reding, Leona Horst, Jenny Barnett, Betsy Anderson, Charles R KrauseAbstract:The nonnative ambrosia beetles Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) are destructive pests of plants and trees growing in ornamental nurseries and tree fruit orchards. Perception of stress-induced volatiles plays an important role in aiding female X. germanus and X. crassiusculus in locating vulnerable hosts, while adult males of both species are flightless and not involved in host selection. Scanning electron microscopy was used to characterize the antennae of both species, which consisted of a scape, funicle, and club. Emphasis was placed on the type, structure, and distribution of sensilla associated with the antennal clubs of female and male X. germanus and X. crassiusculus . Sensilla observed on the anterior surface of the club for females and males of both species include one type of sensillum chaeticum (SC1), one type of sensillum trichodeum (ST1), and five types of sensilla basiconica (SB1–5). Sensilla are distributed in association with two sensory bands and/or a basal cluster. SB1, the most abundant sensilla type found on female and male clubs for both species, appears to be highly porous. No obvious sexual dimorphism was observed regarding sensilla type, but most types are more abundant on the antennal clubs of females compared with males for X. germanus and X. crassiusculus . Possible functions of the sensilla types are discussed based on morphology. These results provide an improved understanding of sensilla associated with X. germanus and X. crassiusculus that will aid electrophysiological investigations into their host selection behavior.
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movement of Xylosandrus germanus coleoptera curculionidae in ornamental nurseries and surrounding habitats
Journal of Economic Entomology, 2015Co-Authors: Michael E. Reding, Jason B. Oliver, Christopher M. Ranger, Blair J Sampson, C T Werle, Peter B. SchultzAbstract:Some exotic ambrosia beetles are damaging pests in ornamental nurseries. Xylosandrus germanus (Blandford) is the most problematic ambrosia beetle in Ohio nurseries. Movement of X. germanus in nurseries has not been characterized, and knowledge is lacking on whether infestations originate from within nurseries or surrounding habitats. Flight activity of X. germanus was monitored in nurseries and adjacent wooded areas to determine the source of beetles infesting nurseries, and characterize their movement within nurseries. Ethanol-baited bottle traps were positioned within wooded areas adjacent to commercial nurseries and within nurseries at various distances from the nursery woodlot interface. Flight activity of overwintered X. germanus occurred in wooded areas adjacent to nurseries before occurrence within nurseries. There was a direct relationship between degree-days and the distance from woodlots when X. germanus were first found in traps in spring, with earlier captures closest to wooded areas and latest ones furthest away into the nursery. X. germanus appeared to move into nurseries from adjacent wooded areas, with numbers trapped within nurseries decreasing with distance away from wooded areas. Trees in the interior of nurseries would appear to be subjected to less attack pressure than trees near the nursery border. Intercepting beetles as they move into nurseries might be an effective strategy to reduce attack pressure on valuable trees.
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ubiquitous volatile compound facilitates efficient host location by a non native ambrosia beetle
Biological Invasions, 2015Co-Authors: Christopher M. Ranger, Michael E. Reding, Patrick C TobinAbstract:Xylosandrus germanus (Blandford), a species native to Asia but currently invading North American and European forests, exploits living, but weakened trees. In response to many sources of stress, trees emit ethanol, which represents an important host-location cue for X. germanus. Because stressed trees can be spatially and temporally variable over a landscape, we assessed the role of olfaction in aiding X. germanus to efficiently locate vulnerable trees during natural dispersal. We conducted a series of experiments and observed that attacks occurred on trees baited with ethanol, but immediately ceased upon removal of the ethanol cue. X. germanus also efficiently located and attacked ethanol-injected trees, but rarely landed on adjacent trees not emitting ethanol, and never attacked these neighboring trees. A spatial analysis of trees attacked by ambrosia beetles within diverse landscapes revealed that only certain host species or cultivars, and only certain individuals within these host species or cultivars, were attacked; ethanol was also detected in the attacked trees, but not in non-attacked trees. Thus, X. germanus uses an efficient olfactory mechanism while orienting among perceived non-hosts to specifically locate trees associated with ethanol. Combined with other attributes, we propose that the remarkable efficiency by which this non-native ambrosia beetle uses volatile cues to locate specific vulnerable hosts across a diverse landscape aids its successful establishment and population spread.
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Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees
2015Co-Authors: Christopher M. Ranger, Peter B. Schultz, Steven D. Frank, Juang H. Chong, Michael E. RedingAbstract:Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and colonization by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flowering dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus were confined with no-choice to stems of flood-stressed and non-flooded C. florida, more ejected sawdust resulting from tunneling activity was associated with the flood-stressed trees. Furthermore, living foundresses, eggs, larvae, and pupae were only detected within galleries created in stems of flood-stressed trees. Despite a capability to attack diverse tree genera, X. germanus and X. crassiusculus efficiently distinguished among varying host qualities and preferentially targeted trees based on their intolerance of flood stress. Non-flooded trees were not preferred or successfully colonized. This study demonstrates the host-selection strategy exhibited by X. germanus and X. crassiusculus in non-native habitats involves detection of stress-induced ethanol emission and early colonization of living but weakened trees.
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Conophthorin enhances the electroantennogram and field behavioural response of Xylosandrus germanus (Coleoptera: Curculionidae) to ethanol
Agricultural and Forest Entomology, 2014Co-Authors: Christopher M. Ranger, Austin M. Gorzlancyk, Peter B. Schultz, Karla M. Addesso, Jason B. Oliver, Michael E. Reding, David W HeldAbstract:Ethanol acts as an attractant that aids Xylosandrus germanus (Blandford) in locating living but weakened hosts. Electroantennogram (EAG) and field trapping experiments were conducted with conophthorin and other selected semiochemicals that function as important olfactory cues for various ambrosia beetles to characterize their effect on the attraction of X. germanus to ethanol and to assess whether EAG responses provide an indication of behavioural activity. Thus, semiochemicals hypothesized to enhance (i.e. conophthorin), reduce (i.e. terpinolene, verbenone) or have a negligible (i.e. lineatin, sulcatol, retusol) effect on the attraction of X. germanus to ethanol were selected for comparative purposes. Ethanol plus conophthorin elicited larger EAG amplitudes than binary (1 : 1) mixtures of ethanol plus the remaining semiochemicals at dilutions of 0.001%, 0.01% and 1% per compound. Conophthorin also enhanced the attraction of X. germanus, Euwallacea validus (Eichhoff) and Cyclorhipidion pelliculosum (Eichhoff) to ethanol under field conditions. By contrast, terpinolene and verbenone reduced the attraction of X. germanus and other ambrosia beetles to ethanol. Semiochemicals that enhance (i.e. conophthorin) or reduce (i.e. terpinolene, verbenone) attraction by X. germanus may improve monitoring and/or management tactics. These results also suggest that EAG responses can indicate field behavioural activity and be useful for screening attractants for X. germanus.
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abundance and distribution of Xylosandrus germanus blandford 1894 coleoptera scolytidae in belgium new observations and an attempt to outline its range
Journal of Pest Science, 2004Co-Authors: Jeanmarc Henin, Veerle VersteirtAbstract:In Belgium, the current distribution and abundance of Xylosandrus germanus (Coleoptera, Scolytidae), a relatively new species to the Belgian fauna, is poorly known. Therefore, data on the range and population levels of this ambrosia beetle, on a regional and local scale respectively, are presented. Based on those results, the beetles’ range is discussed. Among the analysed biotic and abiotic factors that could influence the species’ settlement and population levels, climatic ones, and temperature in particular, seem to exert a crucial influence.
