scholarly journals The Bark Beetle Dendroctonus rhizophagus (Curculionidae: Scolytinae) Has Digestive Capacity to Degrade Complex Substrates: Functional Characterization and Heterologous Expression of an α-Amylase

2020 ◽  
Vol 22 (1) ◽  
pp. 36
Author(s):  
L. Viridiana Soto-Robles ◽  
María Fernanda López ◽  
Verónica Torres-Banda ◽  
Claudia Cano-Ramírez ◽  
Gabriel Obregón-Molina ◽  
...  
Keyword(s):  
Bark Beetle ◽  
Bark Beetles ◽  
Developmental Stages ◽  
Conformational Stability ◽  
Functional Characterization ◽  
Protein A ◽  
Amylolytic Activity ◽  
Digestive Capacity ◽  
Nitrate Ions ◽  
Natural Agents

Dendroctonus-bark beetles are natural agents contributing to vital processes in coniferous forests, such as regeneration, succession, and material recycling, as they colonize and kill damaged, stressed, or old pine trees. These beetles spend most of their life cycle under stem and roots bark where they breed, develop, and feed on phloem. This tissue is rich in essential nutrients and complex molecules such as starch, cellulose, hemicellulose, and lignin, which apparently are not available for these beetles. We evaluated the digestive capacity of Dendroctonus rhizophagus to hydrolyze starch. Our aim was to identify α-amylases and characterize them both molecularly and biochemically. The findings showed that D. rhizophagus has an α-amylase gene (AmyDr) with a single isoform, and ORF of 1452 bp encoding a 483-amino acid protein (53.15 kDa) with a predicted signal peptide of 16 amino acids. AmyDr has a mutation in the chlorine-binding site, present in other phytophagous insects and in a marine bacterium. Docking analysis showed that AmyDr presents a higher binding affinity to amylopectin compared to amylose, and an affinity binding equally stable to calcium, chlorine, and nitrate ions. AmyDr native protein showed amylolytic activity in the head-pronotum and gut, and its recombinant protein, a polypeptide of ~53 kDa, showed conformational stability, and its activity is maintained both in the presence and absence of chlorine and nitrate ions. The AmyDr gene showed a differential expression significantly higher in the gut than the head-pronotum, indicating that starch hydrolysis occurs mainly in the midgut. An overview of the AmyDr gene expression suggests that the amylolytic activity is regulated through the developmental stages of this bark beetle and associated with starch availability in the host tree.

Characterization of two non-native invasive bark beetles, Scolytus schevyrewi and Scolytus multistriatus (Coleoptera: Curculionidae: Scolytinae)

2008 ◽  
Vol 140 (5) ◽  
pp. 527-538 ◽  
Author(s):  
Patricia L. Johnson ◽  
Jane L. Hayes ◽  
John Rinehart ◽  
Walter S. Sheppard ◽  
Steven E. Smith
Keyword(s):  
Bark Beetle ◽  
Bark Beetles ◽  
Developmental Stages ◽  
Random Amplified Polymorphic Dna ◽  
Morphological Characters ◽  
Pcr Analysis ◽  
Scolytus Multistriatus ◽  
Blind Test ◽  
Rapd Pcr ◽  
Elm Bark Beetle

AbstractScolytus schevyrewi Semenov, the banded elm bark beetle, and S. multistriatus Marsham, the smaller European elm bark beetle, are morphologically similar. Reliance on adult external morphological characters for identification can be problematic because of wide within-species variability and the need for good-quality specimens. The inability to identify developmental stages can also hamper early-detection programs. Using two character identification systems, genitalic (aedeagus) morphology, and DNA markers (random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR)) to distinguish S. schevyrewi from S. multistriatus, we examined specimens from geographically distinct populations of both species collected from infested host trees or semiochemical-baited funnel traps. We found that aedeagus morphology can be used to identify the two species. The use of two oligonucleotide primers in the RAPD-PCR analysis yielded distinct DNA banding patterns for the two species. Species identification using RAPD-PCR analysis was validated by a blind test and used to make species identifications of larval specimens. These tools improve the ability to differentiate between S. schevyrewi and S. multistriatus at immature and adult stages, and could be developed and used for other scolytines as well.

A review of histiostomatid mites associated with scolytine bark beetles (Coleoptera: Curculionidae), with a description of Histiostoma shiramba sp. n. (Acari: Histiostomatidae) from galleries of the Sakhalin-fir bark beetle Polygraphus proximus 

2018 ◽  
Vol 23 (12) ◽  
pp. 2373
Author(s):  
Pavel B. Klimov ◽  
A.A. Khaustov
Keyword(s):  
New Species ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Large Scale ◽  
Developmental Stages ◽  
Fungal Spores ◽  
Mite Species ◽  
Species Group ◽  
Invasive Pest ◽  
Polygraphus Proximus

Associations of scolytine bark beetles (Coleoptera: Curculionidae: Scolytinae) and histiostomatid mites (Acari: Histiostomatidae) are reviewed. Histiostomatids are associated with a total of 62 described species of bark beetles in 31 countries of the world, except for South America and Antarctica (262 non-redundant records). Non-accidental records include 21 mite species in the genus Histiostoma and 5 species in the Bonomoia/Probonomoia generic complex. The biological role of histiostomatids associated with bark beetles is largely unknown and needs further investigation. Available observations suggest that histiostomatids living in bark beetle galleries may feed on different fungi, including those pathogenic to the tree host and/or may serve as food supplement for developing bark beetle larvae (e.g., the fungal genus Ophiostoma). However, based on their mouthpart morphology, instead of feeding on fungi directly, histiostomatids may reduce fungal population sizes by releasing fungicides produced by their opisthonotal glands. Both feeding and phoretic stages of the mites commonly vector considerable numbers of fungal spores or conidia, including those of phloem-infesting, blue stain fungi (e.g., Ophiostoma, Ceratocystis, and Alternaria). Here we describe all developmental stages of a new species of the genus Histiostoma, belonging to the piceae-species group that includes many mite species associated with bark beetles. The new species, Histiostoma shiramba sp. n., was found in the galleries of the Sakhalin-fir bark beetle, Polygraphus proximus, an invasive pest that is quickly spreading outside of its native range in the Eastern Palaearctic, causing large-scale destruction of fir forests. We emend the following names (nom. emend.) to agree in gender with the generic name Histiostoma (gender neuter): Histiostoma capillatum, H. conjunctum, H. hungaricum, H. indetonsum, H. irinum, H. longisetum, H. margaritatum, H. medium, H. ovale, H. pannonicum, H. serratum, H. sordidum, H. spinosum, H. sylvestre, H. varium, H. virginianum. The name Histiostoma scheucheri is emended to Histiostoma scheucherae.

BIOLOGY OF SULPHURETYLENCHUS ELONGATUS (NEMATODA: SPHAERULARIIDAE), AND ITS EFFECT ON ITS HOST, SCOLYTUS VENTRALIS (COLEOPTERA: SCOLYTIDAE)

1970 ◽  
Vol 102 (2) ◽  
pp. 197-213 ◽  
Author(s):  
M. Ashraf ◽  
A. A. Berryman
Keyword(s):  
Bark Beetle ◽  
Bark Beetles ◽  
Developmental Stages ◽  
Larval Mortality ◽  
Host Density ◽  
Adult Survival ◽  
Attack Behavior ◽  
Nematode Reproduction ◽  
Nematode Eggs ◽  
Eggs And Larvae

AbstractThe developmental stages of Sulphuretylenchus elongatus, an abundant nematode parasite of Scolytus ventralis, are described. The life cycle was generally synchronized with its host, nematode reproduction usually occurring in the adult beetle after it had attacked a new tree. Reproduction occasionally occurred in the host larva. In these cases encapsulation of some nematode eggs and larvae was observed and the host usually died. Free-living infective stage nematodes emerged from the host, mated in the bark beetle galleries, and the female nematode reinfected bark beetle larvae by penetrating the cuticle.Parasitism by S. elongatus caused delayed emergence, limited flight, and aberrant attack behavior by infected S. ventralis. Female bark beetles were sterilized by heavy infection and partially sterilized by light or moderate infection. The effects of parasitism on males was not as severe. Some egg and larval mortality was attributed to nematode attack, and adult survival was reduced by infection.Parasitism was slightly higher in female bark beetles. The incidence of parasitism decreased somewhat in the upper levels of the tree. Host density appeared to have little effect on per cent parasitism although the degree of super-parasitism increased with host density.

scholarly journals Putative ligand binding sites of two functionally characterized bark beetle odorant receptors

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jothi K. Yuvaraj ◽  
Rebecca E. Roberts ◽  
Yonathan Sonntag ◽  
Xiao-Qing Hou ◽  
Ewald Grosse-Wilde ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Bark Beetle ◽  
Pest Control ◽  
Binding Sites ◽  
Functional Characterization ◽  
Site Directed Mutagenesis ◽  
Odorant Receptors ◽  
Functional Evolution ◽  
General Importance ◽  
Insight Into

Abstract Background Bark beetles are major pests of conifer forests, and their behavior is primarily mediated via olfaction. Targeting the odorant receptors (ORs) may thus provide avenues towards improved pest control. Such an approach requires information on the function of ORs and their interactions with ligands, which is also essential for understanding the functional evolution of these receptors. Hence, we aimed to identify a high-quality complement of ORs from the destructive spruce bark beetle Ips typographus (Coleoptera, Curculionidae, Scolytinae) and analyze their antennal expression and phylogenetic relationships with ORs from other beetles. Using 68 biologically relevant test compounds, we next aimed to functionally characterize ecologically important ORs, using two systems for heterologous expression. Our final aim was to gain insight into the ligand-OR interaction of the functionally characterized ORs, using a combination of computational and experimental methods. Results We annotated 73 ORs from an antennal transcriptome of I. typographus and report the functional characterization of two ORs (ItypOR46 and ItypOR49), which are responsive to single enantiomers of the common bark beetle pheromone compounds ipsenol and ipsdienol, respectively. Their responses and antennal expression correlate with the specificities, localizations, and/or abundances of olfactory sensory neurons detecting these enantiomers. We use homology modeling and molecular docking to predict their binding sites. Our models reveal a likely binding cleft lined with residues that previously have been shown to affect the responses of insect ORs. Within this cleft, the active ligands are predicted to specifically interact with residues Tyr84 and Thr205 in ItypOR46. The suggested importance of these residues in the activation by ipsenol is experimentally supported through site-directed mutagenesis and functional testing, and hydrogen bonding appears key in pheromone binding. Conclusions The emerging insight into ligand binding in the two characterized ItypORs has a general importance for our understanding of the molecular and functional evolution of the insect OR gene family. Due to the ecological importance of the characterized receptors and widespread use of ipsenol and ipsdienol in bark beetle chemical communication, these ORs should be evaluated for their potential use in pest control and biosensors to detect bark beetle infestations.

scholarly journals Drivers of Spruce Bark Beetle (Ips typographus) Infestations on Downed Trees after Severe Windthrow

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1290
Author(s):  
Branislav Hroššo ◽  
Pavel Mezei ◽  
Mária Potterf ◽  
Andrej Majdák ◽  
Miroslav Blaženec ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Ips Typographus ◽  
Wind Damage ◽  
Stem Length ◽  
Local Conditions ◽  
Spruce Bark Beetle ◽  
Management Actions ◽  
Spruce Bark

Research Highlights: Bark beetles are important agents of disturbance regimes in temperate forests, and specifically in a connected wind-bark beetle disturbance system. Large-scale windthrows trigger population growth of the European spruce bark beetle (Ips typographus L.) from endemic to epidemic levels, thereby allowing the killing of Norway spruce trees over several consecutive years. Background and Objectives: There is a lack of evidence to differentiate how outbreaks are promoted by the effects of environmental variables versus beetle preferences of trees from endemic to outbreak. However, little is known about how individual downed-tree characteristics and local conditions such as tree orientation and solar radiation affect beetle colonization of downed trees. Materials and Methods: To answer this question, we investigated the infestation rates and determined tree death categories (uprooted, broken, and stump) in wind-damaged areas in Western Tatra Mts. in Carpathians (Slovakia) from 2014–2016, following a windthrow in May 2014. In total, we investigated 225 trees over eight transects. For every tree, we measured its morphological (tree height, crown characteristics), environmental (solar radiation, terrain conditions, trunk zenith), temporal (time since wind damage), and beetle infestation (presence, location of attack, bark desiccation) parameters. We applied Generalized Additive Mixed Models (GAMM) to unravel the main drivers of I. typographus infestations. Results: Over the first year, beetles preferred to attack broken trees and sun-exposed trunk sides over uprooted trees; the infestation on shaded sides started in the second year along with the infestation of uprooted trees with lower desiccation rates. We found that time since wind damage, stem length, and incident solar radiation increased the probability of beetle infestation, although both solar radiation and trunk zenith exhibited nonlinear variability. Our novel variable trunk zenith appeared to be an important predictor of bark beetle infestation probability. We conclude that trunk zenith as a simple measure defining the position of downed trees over the terrain can anticipate beetle infestation. Conclusions: Our findings contribute to understanding of the bark beetle’s preferences to colonize windthrown trees in the initial years after the primary wind damage. Further, our findings can help to identify trees that are most susceptible to beetle infestation and to prioritize management actions to control beetle population while maintaining biodiversity.

INFESTATION OF CERATOCYSTIS WAGENERI-INFECTED PONDEROSA PINES BY BARK BEETLES (COLEOPTERA: SCOLYTIDAE) IN THE CENTRAL SIERRA NEVADA

1980 ◽  
Vol 112 (7) ◽  
pp. 725-730 ◽  
Author(s):  
D. J. Goheen ◽  
F. W. Cobb
Keyword(s):  
Sierra Nevada ◽  
Bark Beetle ◽  
Ponderosa Pine ◽  
Bark Beetles ◽  
Dendroctonus Brevicomis ◽  
Disease Category ◽  
The Relationship ◽  
Periodic Examination ◽  
Apparently Healthy

AbstractThe relationship between bark beetle infestation of ponderosa pine and severity of infection by Ceratocystis wageneri was investigated by closely monitoring 256 trees (136 apparently healthy, 60 moderately diseased, and 60 severely diseased at initiation of study) for beetle infestation from summer 1972 to fall 1975. Disease ratings were updated by periodic examination, and some trees changed disease category during the study. Ninety trees were infested by Dendroctonus brevicomis, D. ponderosae, or both, five by buprestids alone, and one tree died from effects of the pathogen alone. Sixty-two of the beetle-infested trees were severely diseased at time of infestation, 25 were moderately diseased, and only three were apparently healthy. Thus, the results showed that bark beetles were much more likely to infest infected than healthy trees. Among diseased trees, those with advanced infections were most likely to be infested. There was evidence that buprestids (especially Melanophila spp.) and possibly Ips spp. attacked diseased trees prior to Dendroctonus spp. infestation.

ATTRACTION OF HYLOBIUS PALES (HERBST) (COLEOPTERA: CURCULIONIDAE) TO PHEROMONES OF BARK BEETLES (COLEOPTERA: SCOLYTIDAE)

1990 ◽  
Vol 122 (3) ◽  
pp. 423-427 ◽  
Author(s):  
Thomas W. Phillips
Keyword(s):  
Field Experiment ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Suitable Host ◽  
Male And Female ◽  
Pine Weevil ◽  
Ips Calligraphus ◽  
Hylobius Pales ◽  
Host Resource

AbstractResults of a field experiment indicate that adults of the pine weevil Hylobius pales (Herbst) respond to pheromones of bark beetles. Each sex of H. pales was more attracted to traps baited with the combination of a pine bolt infested with male Ips calligraphus Germar plus the synthetic Dendroctonus Erichson pheromones frontalin and exo-brevicomin, than to traps baited with pine bolts alone. The combined numbers of male and female H. pales caught in traps baited only with Ips calligraphus-infested bolts were significantly greater than numbers caught in traps baited with uninfested control bolts. The attraction of H. pales to bark beetle pheromones may represent a kairomonal response in which weevils exploit semiochemicals from other species that signify a suitable host resource.

Impacts of European spruce bark beetle infestations on Norway spruce BVOC emissions

2021 ◽  
Author(s):  
Erica Jaakkola ◽  
Anna Maria Jönsson ◽  
Per-Ola Olsson ◽  
Maj-Lena Linderson ◽  
Thomas Holst
Keyword(s):  
Climate Change ◽  
Drought Stress ◽  
Norway Spruce ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Atmospheric Environment ◽  
Strong Increase ◽  
Healthy Tree ◽  
Spruce Bark Beetle ◽  
Spruce Bark

<p>Tree killing by spruce bark beetles (<em>Ips typographus</em>) is one of the main disturbances to Norway spruce (<em>Picea abies</em>) forests in Europe and the risk of outbreaks is amplified by climate change with effects such as increased risk of storm felling, tree drought stress and an additional generation of spruce bark beetles per year<sup>[1]</sup>. The warm and dry summer of 2018 triggered large outbreaks in Sweden, the increased outbreaks are still ongoing and affected about 8 million m<sup>3</sup> forest in 2020<sup>[2]</sup>. This is the so far highest record of trees killed by the spruce bark beetle in a single year in Sweden<sup>[2]</sup>. In 1990-2010, the spruce bark beetle killed on average 150 000 m<sup>3</sup> forest per year in southern Sweden<sup>[3]</sup>. Bark beetles normally seek and attack Norway spruces with lowered defense, i.e. trees that are wind-felled or experience prolonged drought stress<sup>[4]</sup>. However, as the number of bark beetle outbreaks increase, the risk of attacks on healthy trees also increase<sup>[5]</sup>. This causes a higher threat to forest industry, and lowers the possibilities to mitigate climate change in terms of potential decreases in carbon uptake if the forests die<sup>[4,5]</sup>. Norway spruce trees normally defend themselves by drenching the beetles in resin<sup>[6]</sup>. The resin in turn contains different biogenic volatile organic compounds (BVOCs), which can vary if the spruce is attacked by bark beetles or not<sup> [4,6]</sup>. The most abundant group of terpenoids (isoprene, monoterpenes and sesquiterpenes), is most commonly emitted from conifers, such as Norway spruce<sup>[7,8]</sup>. The aim of this study was to enable a better understanding of the direct defense mechanisms of spruce trees by quantifying BVOC emissions and its composition from individual trees under attack</p><p>To analyze the bark beetles’ impact on Norway spruce trees a method was developed using tree trunk chambers and adsorbent tubes. This enables direct measurements of the production of BVOCs from individual trees. Three different sites in Sweden, with different environmental conditions were used for the study and samples were collected throughout the growing season of 2019. After sampling, the tubes were analyzed in a lab using automated thermal desorption coupled to a gas chromatograph and a mass spectrometer to identify BVOC species and their quantity.</p><p>The preliminary results show a strong increase in BVOC emissions from a healthy tree that became infested during the data collection. The finalized results expect to enable better understanding of how spruce trees are affected by insect stress from bark beetles, and if bark beetle infestation will potentially result in increased carbon emission in the form of BVOCs.</p><p><strong>References</strong></p><p>[1] Jönsson et al. (2012). Agricultural and Forest Meteorology 166: 188–200<br>[2] Skogsstyrelsen, (2020). https://via.tt.se/pressmeddelande/miljontals-granar-dodades-av-granbarkborren-2020?publisherId=415163&releaseId=3288473<br>[3] Marini et al. (2017). Ecography, 40(12), 1426–1435.<br>[4] Raffa (1991). Photochemical induction by herbivores. pp. 245-276<strong><br></strong>[5] Seidl, et al. (2014). Nature Climate Change, 4(9), 806-810. <br>[6] Ghimire, et al. (2016). Atmospheric Environment, 126, 145-152.<br>[7] Niinemets, U. and Monson, R. (2013). ISBN 978-94-007-6606-8<br>[8] Kesselmeier, J. and Staudt, M. (1999). Journal of Atmospheric Chemistry, 33(1), pp.23-88</p>

Failure of ovarian development in the Douglas-fir bark beetle, Dendroctonus pseudotsugae; an analysis of gut proteases and female-specific proteins

1971 ◽  
Vol 49 (7) ◽  
pp. 1021-1024 ◽  
Author(s):  
T. S. Sahota
Keyword(s):  
High Activity ◽  
Bark Beetle ◽  
Methyl Ether ◽  
Bark Beetles ◽  
Ovarian Development ◽  
Proteolytic Enzymes ◽  
Douglas Fir ◽  
Dendroctonus Pseudotsugae ◽  
Specific Proteins ◽  
Female Specific

The failure of ovarian development in Douglas-fir bark beetles denied of their natural gallery environment and maintained on host bark chips was investigated. Such insects possessed a high activity of proteolytic enzymes in their guts but relatively small amounts of female-specific proteins both in haemolymph and the oocytes. Topical application of farnesyl methyl ether did not increase the activity of gut proteases but resulted in increased amounts of female-specific proteins in haemolymph and ovaries. Thus it appears that the Douglas-fir bark beetles maintained on bark chips do not suffer from an inability to break down the ingested proteins, but synthesize and transfer less than normal amounts of female-specific proteins to the developing oocytes.

scholarly journals Effects of forest roads on Ips sexdentatus infestation in black pine forest

2018 ◽  
Vol 6 (7) ◽  
pp. 828
Author(s):  
Gonca Ece Özcan ◽  
Korhan Enez ◽  
Burak Arıcak
Keyword(s):  
Bark Beetle ◽  
Bark Beetles ◽  
Forest Ecosystems ◽  
Significant Risk ◽  
Pine Forests ◽  
Slope Aspect ◽  
Black Pine ◽  
Forest Roads ◽  
Forest Road ◽  
Ips Sexdentatus

Forest roads are important transportation equipment through forested areas in the rugged, mountainous terrain of northern Turkey. Forest roads harm forest ecosystems due to both the manner in which they are established and how they are used afterwards. Damage to trees that occur during road construction through forests stresses trees, which facilitates outbreaks of bark beetle populations. Bark beetles are significant risk to the health and productivity of Turkish pine forests and to pine forests worldwide. In particular, Ips sexdentatus (Boerner) (Coleoptera, Curculionidae, Scolytinae) is a particularly destructive species of bark beetle in Turkish forests. Their damage to coniferous trees threatens the sustainability of the forest ecosystems. This study primarily aims to assess the intensity of damage that I. sexdentatus inflicts on Pinus nigra J.F.Arnold stands relative to several parameters: the distance to the nearest forest road, aspect (shady - sunny), slope (0–15% or >15%), and other stand characteristics. In this study, we show how damage by an I. sexdentatus infestation in pure black pine stands varies with distance to forest roads and in situ edaphic factors. We sampled 45 plots (400 m2 each), slope, aspect and distances to the nearest forest road was determined using ArcGIS software and the region’s road network overlays. Results showed that trees located within 100 m from the nearest forest road were the most severely damaged ones. The intensity of I. sexdentatus damage was about 16% in a hectare. Trees that were in 16–20 cm diameter class were damaged more often. I. sexdentatus damage did not show any significant correlation with the slope, aspect or degree of canopy closure.

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