Proximity of release points of pheromone components as a factor confusing males of the spotted stem borer,Chilo partellus, approaching the trap

Lux, Sławomir A.; Hassanali, Ahmed; Lwande, Wilber; Njogu, Florence N.

doi:10.1007/bf02066243

Cited by 9 publications

(5 citation statements)

References 15 publications

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“…In contrast, at 8 cm the moth may perceive only a single lowquality signal and, therefore, will arrest its movement toward the source. Similar results have been found previously (Linn and Gaston, 1981;Lux et al, 1994). In contrast, the beetle appeared unaffected by 16 cm spacing between pheromone components; some beetles were captured even when the components were separated by >0.5 m. In the western pine beetle, Dendroctonus brevicomis, attraction to pheromone was observed when components were separated by as much as 4 m (Byers, 1987).…”

Section: Discussionsupporting

confidence: 87%

Attraction Modulated by Spacing of Pheromone Components and Anti-attractants in a Bark Beetle and a Moth

et al. 2011

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Orientation for insects in olfactory landscapes with high semiochemical diversity may be a challenging task. The partitioning of odor plumes into filaments that are interspersed with pockets of 'clean air' may help filament discrimination and upwind flight to attractive sources in the face of inhibitory signals. We studied the effect of distance between odor sources on trap catches of the beetle, Ips typographus, and the moth, Spodoptera littoralis. Insects were tested both to spatially separated pheromone components [cis-verbenol and 2-methyl-3-buten-2-ol for Ips; (Z,E)-9,11-tetradecadienyl acetate and (Z,E)-9,12-tetradecadienyl acetate for Spodoptera], and to separated pheromone and anti-attractant sources [non-host volatile (NHV) blend for Ips; (Z)-9-tetradecenyl acetate for Spodoptera]. Trap catch data were complemented with simulations of plume structure and plume overlap from two separated sources using a photo ionization detector and soap bubble generators. Trap catches of the beetle and the moth were both affected when odor sources in the respective traps were increasingly separated. However, this effect on trap catch occurred at smaller (roughly by an order of magnitude) odor source separation distances for the moth than for the beetle. This may reflect differences between the respective olfactory systems and central processing. For both species, the changes in trap catches in response to separation of pheromone components occurred at similar spacing distances as for separation of pheromone and anti-attractant sources. Overlap between two simulated plumes depended on distance between the two sources. In addition, the number of detected filaments and their concentration decreased with downwind distance. This implies that the response to separated odor sources in the two species might take place under different olfactory conditions. Deploying multiple sources of anti-attractant around a pheromone trap indicated long-distance (meter scale) effects of NHV on the beetle and a potential use for NHV in forest protection.

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Section: Discussionsupporting

confidence: 87%

Attraction Modulated by Spacing of Pheromone Components and Anti-attractants in a Bark Beetle and a Moth

et al. 2011

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“…Thus, reducing the modifier's release rate should at least partially duplicate the effects of displacing the modifier, particularly regarding effects 1 and 3 above. In support of this inference, spatial displacement of a modifier (either a synergist or an inhibitor) from the release point of an insect semiochemical generally produces the same outcome as reducing the dose of or eliminating the modifier: displacement of inhibitors increases (McLaughlin et al 1974;Witzgall and Priesner 1991;Liu and Haynes 1992;Rumbo et al 1993;Potting et al 1999), whereas displacement of synergists reduces insect responses to a semiochemical (Linn and Gaston 1981;Byers 1987;Lux et al 1994). However, in experiment 3, reducing the dose of (+)-endo-brevicomin at the center trap caused a reduction in D. frontalis catches at both the center and the adjacent traps, not an increase in catch at the center trap as would be predicted if the relatively higher catch in the outer traps was attributable simply to a relatively lower concentration of (+)-endo-brevicomin at these locations.…”

Section: Discussionmentioning

confidence: 91%

“…Incremental separation of a pair of traps each baited with different synergistic components of the aggregation pheromone of the western pine beetle, Dendroctonus brevicomis LeConte, caused a rapid, logarithmic decline in attraction of this bark beetle (Byers 1987). For two moth species [cabbage looper, Trichoplusia ni (Hübner), and the spotted stem borer, Chilo partellus (Swinhoe)], separation of the release points of two sex pheromone components by mere centimeters significantly reduced the percentage of males reaching the sources (Linn and Gaston 1981; Lux et al 1994). …”

Section: Discussionmentioning

confidence: 99%

Spatial Displacement of Release Point can Enhance Activity of an Attractant Pheromone Synergist of a Bark Beetle

Sullivan

Mori

2009

J Chem Ecol

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Flight responses of the southern pine beetle, Dendroctonus frontalis Zimmermann, to widely-spaced (>130 m) traps baited with pine volatiles (in turpentine) and the female-produced pheromone component frontalin were enhanced when a bait containing the male pheromone component (+)-endo-brevicomin was attached directly to the trap. However, displacing this bait 4-16 m horizontally from the trap significantly increased its synergistic effect. (+)-endo-Brevicomin enhanced catch to the same degree when the bait was positioned either on the trap or 32 m away. In another experiment, pairs of frontalin/turpentinebaited traps were established with 4 m spacing between traps and >100 m spacing between pairs. Attachment of either a racemic or (+)-endo-brevicomin bait to one trap of a pair caused a significant increase in catch by both traps, but catch in the trap lacking endo-brevicomin was increased more than in its endo-brevicomin-baited twin. In a third experiment, widely-spaced groups of three traps (in a line with 1 and 4 m spacing between the middle and outer traps) were baited uniformly with frontalin and turpentine, and the release rate of (+)-endo-brevicomin from the middle trap was varied across three orders of magnitude. Release rates sufficient to enhance total D. frontalis catch by the trio also caused relatively higher catches to occur in the outer traps than in the middle one. These experiments indicated that both male and female D. frontalis fly to and land preferentially at sources of frontalin and host odors when these are located some distance away from a source of endo-brevicomin. This behavior may have evolved in D. frontalis to allow host-seeking beetles to locate growing, multi-tree infestations while avoiding fully-colonized trees within these infestations. Our data demonstrate that trap spacing alone can qualitatively change the outcome of bait evaluation trials and may explain why many earlier experiments with endo-brevicomin failed to identify it as an aggregation pheromone synergist for D. frontalis. We believe that important aggregative functions of semiochemicals of other bark beetle species may have been similarly overlooked due to choice of experimental procedures.

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“…Second, emitted odor molecules are transported through the air in stable filaments (Murlis et al 1992), and are therefore likely to remain intact until intercepted by insect antennae. Not surprisingly, detailed experiments show a highly refined ability by insects to detect different compounds separated by very small distances (Liu and Haynes 1992, Rumbo et al 1993, Lux et al 1994, Potting et al 1999).…”

Section: Herbivore‐based Studies: Theory and Experimentsmentioning

confidence: 99%

Herbivory and plant resource competition: a review of two interacting interactions

Hambäck¹,

Beckerman²

2003

Oikos

142

165

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2003. Herbivory and plant resource competition: a review of two interacting interactions. -Oikos 101: 26 -37.This review discusses the prevalence and potential for interactive effects between herbivory and competition on plant growth and biomass, and it is apparent that such effects typically arise when there is a mismatch between the spatial scale of herbivore behaviour (food or patch choice) and the spatial heterogeneity of the plant community. Historically, such interactive effects have been examined using two approaches. Studies using the first approach have excluded plant neighbors and herbivores in a factorial experiment, and scored effects on plant biomass. Studies using the second approach have observed herbivore abundance or herbivory on plants with or without plant neighbors, and have identified a large number of mechanisms underlying such interactive effects. The two types of studies have produced somewhat conflicting results, where interactive effects have been commonly observed in studies using the second approach and only rarely in studies using the first approach. This is most likely a consequence of a biased choice of study systems, where studies using the first approach have primarily studied mammalian herbivory while studies using the second approach have been more focussed on insect herbivory. Moreover, studies using the first approach have typically been very small-scale manipulations and this probably precludes most possible interactive effects in systems with mammalian herbivory. This points to the fact that studies examining interactive effects of herbivory and plant competition should more carefully consider the behaviour and life history of herbivores included in the study prior to the design of removal experiments. P. A. Hambäck, School of Forestry and En6ironmentalStudies, 370 Prospect Street, Yale Uni6., New Ha6en, CT 06511, USA. Present address:

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Proximity of release points of pheromone components as a factor confusing males of the spotted stem borer,Chilo partellus, approaching the trap

Cited by 9 publications

References 15 publications

Attraction Modulated by Spacing of Pheromone Components and Anti-attractants in a Bark Beetle and a Moth

Attraction Modulated by Spacing of Pheromone Components and Anti-attractants in a Bark Beetle and a Moth

Spatial Displacement of Release Point can Enhance Activity of an Attractant Pheromone Synergist of a Bark Beetle

Herbivory and plant resource competition: a review of two interacting interactions

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