Arthropods and nematodes co-occurring with the eastern larch beetle,Dendroctonus simplex [Col.: Scolytidae], in Newfoundland

Entomophaga ◽  
1991 ◽  
Vol 36 (2) ◽  
pp. 303-313 ◽  
Author(s):  
David W. Langor
Keyword(s):  
Dendroctonus Simplex

REPRODUCTION AND DEVELOPMENT OF THE EASTERN LARCH BEETLE, DENDROCTONUS SIMPLEX LECONTE (COLEOPTERA: SCOLYTIDAE), IN NEWFOUNDLAND

1987 ◽  
Vol 119 (11) ◽  
pp. 985-992 ◽  
Author(s):  
David W. Langor ◽  
Arthur G. Raske
Keyword(s):  
Adult Males ◽  
Larval Instars ◽  
Dendroctonus Simplex

AbstractOverwintered adults of Dendroctorms simplex LeConte emerged in May and June and produced one generation and two broods in 1983 and 1984. Egg galleries were vertical, slightly sinuous, and significantly longer in first brood trees than in second brood trees . Females laid zero to four eggs per niche . The average number of eggs per gallery was significantly higher in first brood trees (48) than in second brood trees (31). Mean number of eggs per centimetre of gallery was 1.2 for both broods. Mean brood density was significantly higher in first brood trees (50 individuals per 100 cm2) than in second brood trees (23 per 100 cm2).Dendroctonus simplex has four larval instars. Development from egg to adult in the field averaged 60 and 70 days for first and second broods, respectively. Total development at 12, 18, and 24°C in the laboratory averaged 80, 42, and 39 days, respectively. Adult males were significantly smaller than females.

scholarly journals Surveying the endomicrobiome and ectomicrobiome of bark beetles: The case of Dendroctonus simplex

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Audrey-Anne Durand ◽  
Amélie Bergeron ◽  
Philippe Constant ◽  
Jean-Philippe Buffet ◽  
Eric Déziel ◽  
...  
Keyword(s):  
Bark Beetles ◽  
Dendroctonus Simplex

EMERGENCE, HOST ATTACK, AND OVERWINTERING BEHAVIOR OF THE EASTERN LARCH BEETLE, DENDROCTONUS SIMPLEX LECONTE (COLEOPTERA: SCOLYTIDAE), IN NEWFOUNDLAND

1987 ◽  
Vol 119 (11) ◽  
pp. 975-983 ◽  
Author(s):  
David W. Langor ◽  
Arthur G. Raske
Keyword(s):  
Immature Stages ◽  
Air Temperatures ◽  
Early Fall ◽  
Entrance Hole ◽  
Dendroctonus Simplex ◽  
Freezing Temperatures

AbstractOverwintered adults of Dendroctonus simplex LeConte emerged in May and June. One generation and two broods were produced in both 1983 and 1984. Females initiated attacks and males arrived within 2 days. One to four pairs of beetles used each entrance hole but each pair constructed a separate egg gallery.Emergence, host attack, and re-emergence occurred between 1030 and 1700 hours NDT and at mean air temperatures above 4°C. Peaks of attack, which reflect flight peaks, occurred at temperatures above 10°C. About 90% of all parents re-emerged from first brood trees and 61% from second brood trees.Only adults overwintered. Freezing temperatures caused complete mortality of immature stages. Thirty-five percent of new brood adults emerged in the fall and re-entered galleries at the base of trees for hibernation. Adult tolerance to cold increased from early fall to mid-winter.

The Eastern Larch Beetle, Another Threat to our Forests (Coleoptera: Scolytidae)

1989 ◽  
Vol 65 (4) ◽  
pp. 276-279 ◽  
Author(s):  
David W. Langor ◽  
Arthur G. Raske
Keyword(s):  
United States ◽  
North America ◽  
Key Words ◽  
Bark Beetle ◽  
The United States ◽  
Host Material ◽  
Larix Laricina ◽  
Northeastern North America ◽  
Dendroctonus Simplex ◽  
Damage Estimates

Isolated infestations of the eastern larch beetle, Dendroctonus simplex LeConte, have been reported in North America for over 100 years. Historically, this species has been considered a secondary pest of tamarack, Larix laricina (Du Roi) K. Koch, infesting only weakened or recently felled host material. However, recent widespread outbreaks of this bark beetle in northeastern North America and Alaska suggest that the species can be a primary killer of trees. More than 1.4 million m3 of tamarack was killed in the Atlantic provinces of Canada from 1976 to 1986. No damage estimates are available for Quebec and the United States. Fire, flooding, drought and defoliation by insects are often important agents predisposing tamarack to beetle attack and fostering localized build-up of D. simplex populations which then spread to healthy stands resulting in a widespread outbreak. Key Words: Dendroctonus simplex, bark beetle, outbreaks, damage appraisal, predisposing agents, tamarack.

RESPONSE OF EASTERN LARCH BEETLE (COLEOPTERA: SCOLYTIDAE) IN ALASKA TO ITS NATURAL ATTRACTANT AND TO DOUGLAS-FIR BEETLE PHEROMONES

1977 ◽  
Vol 109 (2) ◽  
pp. 289-294 ◽  
Author(s):  
Bruce H. Baker ◽  
Bruce B. Hostetler ◽  
Malcolm M. Furniss
Keyword(s):  
Sex Ratio ◽  
Sex Ratios ◽  
Douglas Fir ◽  
Thanasimus Dubius ◽  
Dendroctonus Pseudotsugae ◽  
Unmated Female ◽  
River Drainage ◽  
Dendroctonus Simplex ◽  
Ips Perturbatus

AbstractIn tests conducted in the McKinley River drainage, Alaska, seudenol combined with α-pinene attracted the most eastern larch beetles, Dendroctonus simplex LeConte. The next most attractive treatments included tamarack log sections infested with either unmated female D. simplex or unmated female Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins, Neither frontalin nor trans- verbenol with α-pinene was attractive. Addition of niethylcyclohexenone (MCH) to the seudenol + α-pinene treatment repressed its attraction by 83%. Sex ratios of simplex responding to logs infested with female simplex or pseudotsugae were equal or favored females, but favored males in the case of seudenol + α-pinene. Addition of MCH shifted the sex ratio in favor of females. Two other scolytid species, Orthotomicus caelatus (Eichhoff) and Ips perturbatus (Eichhoff), were trapped, but were too few to relate to treatments. Two species of clerids were caught on traps: Thanasimus undatulus Say and Thanasimus dubius (L.); the latter is a new Alaskan record.

scholarly journals The symbiotic complex of Dendroctonus simplex: implications in the beetle attack and its life cycle

2019 ◽  
Vol 109 (6) ◽  
pp. 723-732
Author(s):  
A.-A. Durand ◽  
P. Constant ◽  
E. Déziel ◽  
C. Guertin
Keyword(s):  
Defense Mechanisms ◽  
High Throughput Sequencing ◽  
Developmental Stages ◽  
Symbiotic Association ◽  
Forest Pest ◽  
Physiological Processes ◽  
Microbial Assemblage ◽  
Dendroctonus Simplex ◽  
Fungal Microbiota ◽  
Bacteria And Fungi

AbstractThe eastern larch beetle (Dendroctonus simplex Le Conte) is recognized as a serious destructive forest pest in the upper part of North America. Under epidemic conditions, this beetle can attack healthy trees, causing severe damages to larch stands. Dendroctonus species are considered as holobionts, as they engage in multipartite interactions with microorganisms, such as bacteria, filamentous fungi, and yeasts, which are implicated in physiological processes of the insect, such as nutrition. They also play a key role in the beetle's attack, as they are responsible for the detoxification of the subcortical environment and weaken the tree's defense mechanisms. The eastern larch beetle is associated with bacteria and fungi, but their implication in the success of the beetle remains unknown. Here, we investigated the bacterial and fungal microbiota of this beetle pest throughout its ontogeny (pioneer adults, larvae and pupae) by high-throughput sequencing. A successional microbial assemblage was identified throughout the beetle developmental stages, reflecting the beetle's requirements. These results indicate that a symbiotic association between the eastern larch beetle and some of these microorganisms takes place and that this D. simplex symbiotic complex is helping the insect to colonize its host tree and survive the conditions encountered.

scholarly journals Fungal communities associated with the eastern larch beetle: diversity and variation within developmental stages

2017 ◽  
Author(s):  
Audrey-Anne Durand ◽  
Jean-Philippe Buffet ◽  
Philippe Constant ◽  
Eric Déziel ◽  
Claude Guertin
Keyword(s):  
Filamentous Fungi ◽  
Bark Beetles ◽  
Developmental Stages ◽  
18S Rrna Gene ◽  
Fungal Communities ◽  
Rrna Gene ◽  
Comprehensive Overview ◽  
Defense Compounds ◽  
Larval Stages ◽  
Dendroctonus Simplex

AbstractBacterial and fungal communities associated with bark beetles, especially some Dendroctonus species, mediate challenging aspects of the subcortical habitat for their hosts. Filamentous fungi and yeasts are important in various metabolic processes of certain bark beetles, with involvement in nutrition, protection and detoxification of plant defense compounds. The eastern larch beetle, Dendroctonus simplex, is recognized as a serious forest pest in the upper part of North America. Although D. simplex is well studied, the fungal communities and their ecological role remain to be investigated. Here, using 18S rRNA gene pyrosequencing, we provide a comprehensive overview of the yeasts and filamentous fungi associated with the eastern larch beetle and compare fungal communities between different developmental stages and microenvironments. Fungal mycobiome associated with the galleries was also investigated. Our study has unveiled an unexpected fungal diversity associated with the developmental stages. Significant differences in species richness between the developmental stages were determined. Yeasts were found to be predominant in the adult and larval stages, whereas filamentous fungi were most prevalent in the pupae. Our results indicate a possible implication of yeasts in the eastern larch beetle nutrition.

scholarly journals The symbiotic complex of Dendroctonus simplex: implications in the beetle attack and its life cycle

2018 ◽  
Author(s):  
Audrey-Anne Durand ◽  
Philippe Constant ◽  
Eric Déziel ◽  
Claude Guertin
Keyword(s):  
Defense Mechanisms ◽  
High Throughput Sequencing ◽  
Developmental Stages ◽  
Symbiotic Association ◽  
Forest Pest ◽  
Physiological Processes ◽  
Microbial Assemblage ◽  
Dendroctonus Simplex ◽  
Fungal Microbiota ◽  
Bacteria And Fungi

AbstractThe eastern larch beetle (Dendroctonus simplex Le Conte) is recognized as a serious destructive forest pest in the upper part of North America. Under epidemic conditions, this beetle can attack healthy trees, causing severe damages to larch stands. Dendroctonus species are considered as holobionts, as they engage in multipartite interactions with microorganisms, such as bacteria, filamentous fungi, and yeasts, which are implicated in physiological processes of the insect, such as nutrition. They also play a key role in the beetle’s attack, as they are responsible for the detoxification of the subcortical environment and weaken the tree’s defense mechanisms. The eastern larch beetle is associated with bacteria and fungi, but their implication in the success of the beetle remains unknown. Here, we investigated the bacterial and fungal microbiota of this beetle pest throughout its ontogeny (pioneer adults, larvae and pupae) by high-throughput sequencing. A successional microbial assemblage was identified throughout the beetle developmental stages, reflecting the beetle’s requirements. These results indicate that a symbiotic association between the eastern larch beetle and some of these microorganisms takes place and that this D. simplex symbiotic complex is helping the insect to colonize its host tree and survive the conditions encountered.

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