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Christopher J. Fettig - One of the best experts on this subject based on the ideXlab platform.
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Native Bark Beetles and Wood Borers in Mediterranean Forests of California
Insects and Diseases of Mediterranean Forest Systems, 2016Co-Authors: Christopher J. FettigAbstract:Several species of bark beetles (Coleoptera: Curculionidae, Scolytinae), and to a much lesser extent wood borers (primarily Coleoptera: Buprestidae and Cerambycidae), are capable of causing conifer mortality in Mediterranean forests of California, U.S. This mortality is an important part of the ecology of these ecosystems, but the economic and social implications can be significant when outbreaks occur. I review the ecology, impact and management of the more notable species, including western pine beetle, Dendroctonus brevicomis LeConte, mountain pine beetle, D. ponderosae Hopkins, Jeffrey pine beetle, D. jeffreyi Hopkins, red turpentine beetle, D. valens LeConte, California fivespined ips, Ips paraconfusus Lanier, pine engraver, I. pini (Say), pinyon ips, I. confusus LeConte, fir engraver, Scolytus ventralis LeConte, cedar bark beetles, Phloeosinus spp., and several wood borers.
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© Birkhäuser Verlag, Basel, 2007 DOI 10.1007/s00049-007-0378-8
2014Co-Authors: William P. Shepherd, Dezene P. W. Huber, Steven J. Seybold, Christopher J. FettigAbstract:Antennal responses of the western pine beetle, Dendroctonus brevicomis (Coleoptera: Curculionidae), to stem volatiles of its primary host, Pinus ponderosa, and nine sympatric nonhost angiosperms and conifer
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Responses of Dendroctonus brevicomis (Coleoptera: Curculionidae) in behavioral assays: implications to development of a semiochemical-based tool for tree protection.
Journal of economic entomology, 2012Co-Authors: Christopher J. Fettig, Stephen R. Mckelvey, Christopher P. Dabney, Dezene P. W. HuberAbstract:ABSTRACT Currently, techniques for managing western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), infestations are limited to tree removals (thinning) that reduce stand density and presumably host susceptibility, and/or the use of insecticides to protect individual trees. There continues to be significant interest in developing an effective semiochemicalbased tool for protecting trees from D. brevicomis attack, largely as an alternative to conventional insecticides. The responses of D. brevicomis to tree volatiles and verbenone were documented in eight experiments (trapping assays) conducted over a 4-yr period in which 88,942 individuals were collected. Geraniol, a tree volatile unique to Pinus ponderosa that elicits female-specific antennal responses in D. brevicomis, did not affect D. brevicomis behavior. Blends of two green leaf alcohols [hexanol + (Z)-3-hexen-1-ol] tested at two release rates (5.0 and 100.0 mg/d) had no effect on the response of D. brevicomis to...
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Effects of prescribed fire and season of burn on direct and indirect levels of tree mortality in Ponderosa and Jeffrey Pine Forests in California, USA.
Forest Ecology and Management, 2010Co-Authors: Christopher J. Fettig, Stephen R. Mckelvey, Daniel R. Cluck, Sheri L. Smith, William J. OtrosinaAbstract:Abstract Many forests that historically experienced frequent low-intensity wildfires have undergone extensive alterations during the past century. Prescribed fire is now commonly used to restore these fire-adapted forest ecosystems. In this study, we examined the influence of prescribed burn season on levels of tree mortality attributed to prescribed fire effects (direct mortality) and bark beetles (Coleoptera: Curculionidae, Scolytinae) (indirect mortality) in ponderosa pine, Pinus ponderosa Dougl. ex Laws., and Jeffrey pine, Pinus jeffreyi Grev. and Balf., forests in California, USA. A total of 816 trees (9.9% of all trees) died during this 3-yr study. Significantly higher levels of tree mortality (all sources) occurred following early and late season burns compared to the untreated control, but no significant difference was observed between burn treatments. The majority (461 trees) of tree deaths were attributed to direct mortality from prescribed burns and was strongly concentrated (391 trees) in the smallest diameter class ( 50.7 cm dbh), significantly higher levels of tree mortality occurred on early season burns than the untreated control, most of which resulted from indirect mortality attributed to bark beetle attacks, specifically western pine beetle, Dendroctonus brevicomis LeConte, and mountain pine beetle, D . ponderosae Hopkins. Red turpentine beetle, D . valens LeConte, was the most common bark beetle species found colonizing trees, but tree mortality was not attributed to this species. A total of 355 trees (4.3% of all trees) were killed by bark beetles. Dendroctonus brevicomis (67 trees, 18.9%) and D . ponderosae (56 trees, 15.8%), were found colonizing P . ponderosa ; and Jeffrey pine beetle, D . jeffreyi Hopkins, was found colonizing P . jeffreyi (seven trees, 2.0%). We also found pine engraver, Ips pini (Say) (137 trees, 38.6%), and, to a much lesser extent, Orthotomicus (= Ips ) latidens (LeConte) (85 trees, 23.9%) and emarginate ips, I . emarginatus (LeConte) (3 trees, 0.8%) colonizing P . ponderosa and P . jeffreyi . Few meaningful differences in levels of indirect tree mortality attributed to bark beetle attack were observed between early and late season burns. The incidence of root and root collar pathogens ( Leptographium and Sporothrix spp.), including species known to be vectored by bark beetles, was low (18% of trees sampled). The implications of these and other results to management of P . ponderosa and P . jeffreyi forests are discussed in detail.
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evaluation of multiple funnel traps and stand characteristics for estimating western pine beetle caused tree mortality
Journal of Economic Entomology, 2009Co-Authors: Christopher J. Hayes, Christopher J. Fettig, Laura D MerrillAbstract:ABSTRACT The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae: Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Dougl. ex Laws., mortality in much of western North America. This study was designed to quantify relationships between western pine beetle trap catches [including those of its primary invertebrate predator Temnochila chlorodia (Mannerheim) (Coleoptera: Trogositidae)], and levels of tree mortality attributed to western pine beetle at 44 trapping sites (stands) and within five general locations (forests) in California. Furthermore, we evaluated relationships between forest stand characteristics and levels of western pine beetle-caused tree mortality. Preliminary analyses were conducted by Pearson's correlation coefficient (r) using tree mortality per hectare and percentage of tree mortality and 10 potential predictor variables. All predictor variables that had significant correlations (western pine beetle per day, western pine beetle: T. chlorodia, pe...
Dezene P. W. Huber - One of the best experts on this subject based on the ideXlab platform.
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© Birkhäuser Verlag, Basel, 2007 DOI 10.1007/s00049-007-0378-8
2014Co-Authors: William P. Shepherd, Dezene P. W. Huber, Steven J. Seybold, Christopher J. FettigAbstract:Antennal responses of the western pine beetle, Dendroctonus brevicomis (Coleoptera: Curculionidae), to stem volatiles of its primary host, Pinus ponderosa, and nine sympatric nonhost angiosperms and conifer
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Efficacy of “Verbenone Plus” for Protecting Ponderosa Pine Trees and Stands from Dendroctonus brevicomis (Coleoptera: Curculionidae) Attack in British Columbia and California
Journal of Economic Entomology, 2012Co-Authors: Christophe J Fettig, Dezene P. W. Huber, Stephen R. Mckelvey, Christopher P. Dabney, Cameron G. Lait, Donald L. Fowler, John H. BordenAbstract:ABSTRACT The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Douglas ex Lawson, mortality in much of western North America. We review several years of research that led to the identification of Verbenone Plus, a novel four-component semiochemcial blend [acetophenone, (E)2-hexen-1-ol + (Z)-2-hexen-1-ol, and (-)-verbenone] that inhibits the response of D. brevicomis to attractant-baited traps, and examine the efficacy of Verbenone Plus for protecting individual trees and forest stands from D. brevicomis infestations in British Columbia and California. In all experiments, semiochemicals were stapled around the bole of treated trees at ≈2 m in height. (-)-Verbenone alone had no effect on the density of total attacks and successful attacks by D. brevicomis on attractant-baited P. ponderosa, but significantly increased the percentage of pitchouts (unsuccessful D. brevicomis attacks). Verbenone Plus significantly re...
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Responses of Dendroctonus brevicomis (Coleoptera: Curculionidae) in behavioral assays: implications to development of a semiochemical-based tool for tree protection.
Journal of economic entomology, 2012Co-Authors: Christopher J. Fettig, Stephen R. Mckelvey, Christopher P. Dabney, Dezene P. W. HuberAbstract:ABSTRACT Currently, techniques for managing western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), infestations are limited to tree removals (thinning) that reduce stand density and presumably host susceptibility, and/or the use of insecticides to protect individual trees. There continues to be significant interest in developing an effective semiochemicalbased tool for protecting trees from D. brevicomis attack, largely as an alternative to conventional insecticides. The responses of D. brevicomis to tree volatiles and verbenone were documented in eight experiments (trapping assays) conducted over a 4-yr period in which 88,942 individuals were collected. Geraniol, a tree volatile unique to Pinus ponderosa that elicits female-specific antennal responses in D. brevicomis, did not affect D. brevicomis behavior. Blends of two green leaf alcohols [hexanol + (Z)-3-hexen-1-ol] tested at two release rates (5.0 and 100.0 mg/d) had no effect on the response of D. brevicomis to...
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Response of Dendroctonus brevicomis to different release rates of nonhost angiosperm volatiles and verbenone in trapping and tree protection studies
Journal of Applied Entomology, 2009Co-Authors: Christophe J Fettig, Christopher P. Dabney, Stephen R. Mckelvey, Robert R. Borys, Dezene P. W. HuberAbstract:A blend of eight nonhost angiosperm volatiles (benzyl alcohol, benzaldehyde, guaiacol, nonanal, salicylaldehyde, (E)-2-hexenal, (E)-2-hexen-1-ol and (Z)-2-hexen-1-ol) without [NAV] and with [NAVV] (-)-verbenone (4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-one) were tested at low (L), medium (M) and high (H) release rates for their ability to reduce attraction of western pine beetle, Dendroctonus brevicomis LeConte, to attractant-baited (exo-brevicomin [racemic, 3 mg/d], frontalin [racemic, 3 mg/d] and myrcene [18 mg/d]) multiple funnel traps. NAV-L (40 mg/d) had no significant effect. Verbenone alone (50 mg/d) and NAV-M (240 mg/d) both significantly reduced attraction, but no significant difference was observed between the two treatment means. NAV-H (430 mg/d) significantly reduced catches by ∼60% and 78% compared to verbenone alone and the baited control, respectively. In a second experiment, combining (-)-verbenone with NAV (NAVV) increased the effects observed in Experiment 1. NAVV-M (240 mg/d) resulted in an ∼69% and 83% reduction in trap catch compared to verbenone alone and the baited control, respectively. Significantly fewer D. brevicomis were captured in NAVV-H (430 mg/d) than any other treatment resulting in an ∼93% reduction in trap catch compared to the baited control. In a third experiment, NAVV was tested at three release rates for its ability to protect individual ponderosa pines, Pinus ponderosa Dougl. ex Laws., from attack by D. brevicomis. Cumulative release rates varied in direct proportion to tree diameter, but represented quarter, half and full NAVV rates. NAVV significantly reduced the density of D. brevicomis attacks, D. brevicomis successful attacks, and levels of tree mortality on attractant-baited trees. Only three of 15 NAVV-treated trees died from D. brevicomis attack while ∼93% mortality (14/15) was observed in the untreated, baited control. Quarter and half rates were ineffective for reducing tree mortality.
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Nonhost angiosperm volatiles and verbenone protect individual ponderosa pines from attack by western pine beetle and red turpentine beetle (Coleoptera: Curculionidae, Scolytinae)
Western Journal of Applied Forestry, 2008Co-Authors: Christophe J Fettig, Christopher P. Dabney, Stephen R. Mckelvey, Dezene P. W. HuberAbstract:Abstract Nonhost angiosperm volatiles (NAV) and verbenone were tested for their ability to protect individual ponderosa pines, Pinus ponderosa Dougl. ex. Laws., from attack by western pine beetle (WPB), Dendroctonus brevicomis LeConte, and red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae). A combination of (−)-verbenone and eight NAVs [benzyl alcohol, benzaldehyde, guaiacol, nonanal, salicylaldehyde, (E)-2-hexenal, (E)-2-hexen-1-ol, and (Z)-2-hexen-1-ol] (NAVV) significantly reduced the density of WPB attacks and WPB successful attacks on attractant-baited trees. A significantly higher percentage of pitchouts (unsuccessful WPB attacks) occurred on NAVV-treated trees during two of three sample dates. In addition, significantly fewer RTB attacks were observed on NAVV-treated trees during all sampling dates. The application of NAVV to individual ponderosa pines significantly reduced tree mortality, with only 4 of 30 attractant-baited trees dying from bark beetle attack while 50% mortality (15/30) was observed in the untreated, baited control. To our knowledge, this is the first report establishing the effectiveness of NAVs and verbenone for protecting individual ponderosa pines from WPB attack.
Christophe J Fettig - One of the best experts on this subject based on the ideXlab platform.
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Efficacy of “Verbenone Plus” for Protecting Ponderosa Pine Trees and Stands from Dendroctonus brevicomis (Coleoptera: Curculionidae) Attack in British Columbia and California
Journal of Economic Entomology, 2012Co-Authors: Christophe J Fettig, Dezene P. W. Huber, Stephen R. Mckelvey, Christopher P. Dabney, Cameron G. Lait, Donald L. Fowler, John H. BordenAbstract:ABSTRACT The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Douglas ex Lawson, mortality in much of western North America. We review several years of research that led to the identification of Verbenone Plus, a novel four-component semiochemcial blend [acetophenone, (E)2-hexen-1-ol + (Z)-2-hexen-1-ol, and (-)-verbenone] that inhibits the response of D. brevicomis to attractant-baited traps, and examine the efficacy of Verbenone Plus for protecting individual trees and forest stands from D. brevicomis infestations in British Columbia and California. In all experiments, semiochemicals were stapled around the bole of treated trees at ≈2 m in height. (-)-Verbenone alone had no effect on the density of total attacks and successful attacks by D. brevicomis on attractant-baited P. ponderosa, but significantly increased the percentage of pitchouts (unsuccessful D. brevicomis attacks). Verbenone Plus significantly re...
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efficacy of verbenone plus for protecting ponderosa pine trees and stands from Dendroctonus brevicomis coleoptera curculionidae attack in british columbia and california
Journal of Economic Entomology, 2012Co-Authors: Christophe J Fettig, Dezene P W Hube, Stephen R. Mckelvey, Christopher P. Dabney, Camero G Lai, Donald L Fowle, J H OrdeAbstract:ABSTRACT The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Douglas ex Lawson, mortality in much of western North America. We review several years of research that led to the identification of Verbenone Plus, a novel four-component semiochemcial blend [acetophenone, (E)2-hexen-1-ol + (Z)-2-hexen-1-ol, and (-)-verbenone] that inhibits the response of D. brevicomis to attractant-baited traps, and examine the efficacy of Verbenone Plus for protecting individual trees and forest stands from D. brevicomis infestations in British Columbia and California. In all experiments, semiochemicals were stapled around the bole of treated trees at ≈2 m in height. (-)-Verbenone alone had no effect on the density of total attacks and successful attacks by D. brevicomis on attractant-baited P. ponderosa, but significantly increased the percentage of pitchouts (unsuccessful D. brevicomis attacks). Verbenone Plus significantly re...
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Efficacy of Verbenone for Protecting Ponderosa Pine Stands From Western Pine Beetle (Coleoptera: Curculionidae: Scolytinae) Attack in California
Journal of Economic Entomology, 2009Co-Authors: Christophe J Fettig, Stephen R. Mckelvey, Christopher P. Dabney, Robert R. Borys, Shakeeb M. Hamud, Lori J. Nelson, Steven J. SeyboldAbstract:ABSTRACT The western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae: Scolytinae), is a major cause of ponderosa pine, Pinus ponderosa Dougl. ex Laws., mortality in much of western North America. Currently, techniques for managing D. brevicomis infestations are limited. Verbenone (4,6,6-trimethylbicyclo [3.1.1] hept-3-en-2-one) is an antiaggregation pheromone of several Dendroctonus spp., including D. brevicomis, and it has been registered as a biopesticide for control of mountain pine beetle, Dendroctonus ponderosae Hopkins, and southern pine beetle, Dendroctonus frontalis Zimmermann. We evaluated the efficacy of a 5-g verbenone pouch [82%-(-); 50 mg/d] applied at 125 U/ha for protecting P. ponderosa stands (2 ha) from D. brevicomis attack over a 3-yr period. No significant differences in levels of D. brevicomis-caused tree mortality or the percentage of unsuccessfully attacked trees were found between verbenone-treated and untreated plots during each year or cumulatively over the...
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Response of Dendroctonus brevicomis to different release rates of nonhost angiosperm volatiles and verbenone in trapping and tree protection studies
Journal of Applied Entomology, 2009Co-Authors: Christophe J Fettig, Christopher P. Dabney, Stephen R. Mckelvey, Robert R. Borys, Dezene P. W. HuberAbstract:A blend of eight nonhost angiosperm volatiles (benzyl alcohol, benzaldehyde, guaiacol, nonanal, salicylaldehyde, (E)-2-hexenal, (E)-2-hexen-1-ol and (Z)-2-hexen-1-ol) without [NAV] and with [NAVV] (-)-verbenone (4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-one) were tested at low (L), medium (M) and high (H) release rates for their ability to reduce attraction of western pine beetle, Dendroctonus brevicomis LeConte, to attractant-baited (exo-brevicomin [racemic, 3 mg/d], frontalin [racemic, 3 mg/d] and myrcene [18 mg/d]) multiple funnel traps. NAV-L (40 mg/d) had no significant effect. Verbenone alone (50 mg/d) and NAV-M (240 mg/d) both significantly reduced attraction, but no significant difference was observed between the two treatment means. NAV-H (430 mg/d) significantly reduced catches by ∼60% and 78% compared to verbenone alone and the baited control, respectively. In a second experiment, combining (-)-verbenone with NAV (NAVV) increased the effects observed in Experiment 1. NAVV-M (240 mg/d) resulted in an ∼69% and 83% reduction in trap catch compared to verbenone alone and the baited control, respectively. Significantly fewer D. brevicomis were captured in NAVV-H (430 mg/d) than any other treatment resulting in an ∼93% reduction in trap catch compared to the baited control. In a third experiment, NAVV was tested at three release rates for its ability to protect individual ponderosa pines, Pinus ponderosa Dougl. ex Laws., from attack by D. brevicomis. Cumulative release rates varied in direct proportion to tree diameter, but represented quarter, half and full NAVV rates. NAVV significantly reduced the density of D. brevicomis attacks, D. brevicomis successful attacks, and levels of tree mortality on attractant-baited trees. Only three of 15 NAVV-treated trees died from D. brevicomis attack while ∼93% mortality (14/15) was observed in the untreated, baited control. Quarter and half rates were ineffective for reducing tree mortality.
Timothy D. Paine - One of the best experts on this subject based on the ideXlab platform.
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Strong Differentiation in Mitochondrial Dna of Dendroctonus brevicomis (Coleoptera: Scolytidae) on Different Subspecies of Ponderosa Pine
Annals of the Entomological Society of America, 1999Co-Authors: Scott T. Kelley, Jeffry B. Mitton, Timothy D. PaineAbstract:Earlier phylogenetic analysis of the bark beetle genus Dendroctonus based on mitochondrial DNA (mtDNA) uncovered large genetic distances between 2 populations of Dendroctonus brevicomis, 1 in California and 1 in Colorado. The genetic distance between the 2 populations was equivalent to that observed between fully recognized sister species of Dendroctonus and suggested the presence of 2 cryptic species. To test this hypothesis, we sampled D. brevicomis from 12 populations across its range. Using polymerase chain reaction, we amplified a 1,250-bp region of the mtDNA gene cytochrome oxidase I (COX I). A restriction site survey using 8 enzymes revealed 8 fixed differences between western (California, Oregon, Idaho, and British Columbia) and eastern (Colorado, Utah, Arizona, New Mexico) populations, suggesting that D. brevicomis is composed of 2 cryptic species. Moreover, the distribution of these 2 groups corresponds with the distributions of Pinus ponderosa variety scopulorum and variety ponderosa , the principal hosts of D. brevicomis over the majority of its range. We suggest that these populations of D. brevicomis may have become reproductively isolated as a consequence of the geographic separation of the host varieties.
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Response ofDendroctonus brevicomis Le Conte (Coleoptera: Scolytidae) to different release rates and ratios of aggregation semiochemicals and the inhibitors verbenone and ipsdienol.
Journal of Chemical Ecology, 1994Co-Authors: Sally L. Bertram, Timothy D. PaineAbstract:The response of western pine beetle,Dendroctonus brevicomis Le Conte, to different release rates of the aggregation semiochemicals (attractants)exo-brevicomin, frontalin, and myrcene and the inhibitors verbenone and ipsdienol was investigated. Release rates of verbenone ranging from 0.18 mg/ 24 hr to 1.2 mg/24 hr did not result in significant reductions in mean trap catch ofD. brevicomis. In contrast, very low release rates of ipsdienol (0.02–0.4 mg/24 hr) significantly reduced trap catch compared to controls. The combination of verbenone and ipsdienol, released at rates above 0.09 and 0.02 mg/24 hr, respectively, resulted in significantly lower trap catches ofD. brevicomis in attractant-baited traps. Results of an experiment testing a factorial combination of different release rates of verbenone and attractants suggest that response is not ratio-specific. The response curve ofD. brevicomis to the levels of verbenone was similar across all levels of attractants, while the response to equivalent ratios of attractants to verbenone was not similar, suggesting that the behavior of the beetles is primarily influenced by the absolute release rate of verbenone.
Brian T. Sullivan - One of the best experts on this subject based on the ideXlab platform.
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Evidence for Semiochemical Divergence Between Sibling Bark Beetle Species: Dendroctonus brevicomis and Dendroctonus barberi
Journal of Chemical Ecology, 2021Co-Authors: Brian T. Sullivan, Amanda M. Grady, Richard W. Hofstetter, Deepa S. Pureswaran, Cavell Brownie, Daniel Cluck, Tom W. Coleman, Andrew Graves, Elizabeth Willhite, Lia SpiegelAbstract:We investigated geographic variation in the semiochemistry of major disturbance agents of western North American pine forests, Dendroctonus brevicomis Le Conte and Dendroctonus barberi Hopkins (Coleoptera: Curculionidae: Scolytinae), species separated by the Great Basin in the USA that until recently were synonymous. At 15 sites in the western USA and northern Mexico, beetle populations were examined to determine (1) pheromone production by solitary, mining females, (2) male electroantennogram amplitudes in response to known semiochemicals for the genus, or (3) relative attractiveness of two female-produced pheromone components ( endo - and exo- brevicomin) and two host odors ( alpha -pinene and myrcene) to beetles in the field. Compared to female beetles collected east of the Great Basin ( D. barberi ), western females ( D. brevicomis ) produced a consistently higher proportion of, and male antenna were correspondingly more sensitive to, the exo - than the endo -isomer of brevicomin. With the exception of one sampling location (where no preference was observed), beetles west of the Great Basin were more attracted to exo - than endo - brevicomin trap lures, whereas eastern beetles displayed the reverse preference. In contrast, there was not a consistent difference between these populations regarding relative attraction or olfactory response to myrcene or alpha -pinene, although some geographic variability was evident. These data show that the semiochemical systems of D. brevicomis and D. barberi have diverged and corroborate genetic and morphological evidence that they are distinct, allopatric species.
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Cryptic Species Discrimination in Western Pine Beetle, Dendroctonus brevicomis LeConte (Curculionidae: Scolytinae), Based on Morphological Characters and Geometric Morphometrics
Insects, 2019Co-Authors: O. Valerio-mendoza, Brian T. Sullivan, Francisco Armendáriz-toledano, Gerardo Cuéllar-rodríguez, Jose F. Negron, Jazmín García-román, Moises Becerril, Gerardo ZúñigaAbstract:The western pine beetle (WPB), Dendroctonus brevicomis LeConte, is a major mortality agent of pines in North America. A total of 706 adults of WPB from 81 geographical sites were analyzed with traditional and geometric morphometric methods to evaluate the variation of discrete and quantitative morphological characters with particular attention to the antenna, spermatheca, and seminal rod. Principal coordinates and canonical variate analyses supported three geographical groups in WPB: (1) West, from British Columbia to southern California along the Pacific coast, Idaho, and Montana; (2) East-SMOC, including Nevada, Utah, Colorado, Arizona, New Mexico, Texas, Chihuahua, and Durango; and (3) SMOR, including Coahuila, Nuevo Leon, and Tamaulipas. The pubescence length on the elytral declivity was a robust character for separating West specimens from the other groups. Additionally, the genitalia shape both female and male in dorsal view was a reliable character for discriminating among groups. Based on these results, which agree with genetic and chemical ecology evidence, we herein reinstate Dendroctonus barberi Hopkins (East-SMOC group) and remove it from synonymy with D. brevicomis (West group). Differences in the spermatheca and seminal rod shape of SMOR specimens suggest that these populations might be a different species from D. barberi and D. brevicomis.
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Attraction of the southern pine beetle, Dendroctonus frontalis, to pheromone components of the western pine beetle, Dendroctonus brevicomis (Coleoptera: Curculionidae: Scolytinae), in an allopatric zone.
Environmental entomology, 2008Co-Authors: Deepa S. Pureswaran, Richard W. Hofstetter, Brian T. SullivanAbstract:Subtle differences in pheromone components of sympatric species should be attractive only to the producing species and unattractive or repellent to the nonproducing species, and thereby maintain reproductive isolation and reduce competition between species. Bark beetles Dendroctonus brevicomis and D. frontalis (Coleoptera: Curculionidae) are known to have common pheromone components, except for exo-brevicomin, which is produced by D. brevicomis. We predicted that D. frontalis would not respond to exo-brevicomin outside of the zone of sympatry with D. brevicomis. We conducted a field experiment to determine the effect of exo-brevicomin on attraction of D. frontalis and associated species in Mississippi. We determined whether D. frontalis pheromone production differed inside and outside the sympatric zone and compared the pheromone profiles with D. brevicomis within the sympatric zone. Trapping studies revealed that D. frontalis can perceive and respond positively to exo-brevicomin, an aggregation pheromone of a sympatric congener (D. brevicomis), at locations hundreds of kilometers outside the sympatric zone. Qualitative pheromone profiles showed that both species emit similar pheromone components: frontalin, endo-brevicomin, exo-brevicomin, trans-verbenol, verbenone, and myrtenol. Although not previously reported, D. frontalis males from Arizona produced exo-brevicomin. The predator Thanasimus dubius did not discriminate traps baited with exo-brevicomin and was most attracted to traps with frontalin. Hylastes beetles were significantly attracted to traps baited with exo-brevicomin in combination with other compounds. Our results raise new practical and evolutionary questions on the role of exo-brevicomin in the behavioral ecology of D. frontalis. The addition of exo-brevicomin to the current lure might increase the efficiency of trapping programs in the southeastern United States.