Seconds-Long Preexposures to Pheromone from Rubber Septum or Polyethelene Tube Dispensers Alters Subsequent Behavioral Responses of Male Grapholita molesta (Lepidoptera: Tortricidae) in a Sustained-Flight Tunnel (original) (raw)
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Environmental Entomology, 2005
Male Oriental fruit moths, Grapholita molesta (Busck), were brießy preexposed in a wind tunnel to plumes from a rubber septum lure releasing a three-component, optimally attractive pheromone blend for this species or to plumes generated by Isomate-M Rosso pheromone dispensers. The objectives were to determine how brief preexposures to low-and high-dosage pheromone dispensers affect initiation of anemotaxis, duration of sustained anemotactic ßight, and peripheral sensitivity 15 min and 24 h after exposure. A greater proportion of G. molesta males took ßight and successfully oriented toward a lure 15 min after brießy orienting in plumes generated by an identical lure compared with unexposed, naṏve moths or control moths preexposed to clean air. In addition, the proportion of males contacting a lure or orienting to the lure without source contact 24 h after a preexposure was not signiÞcantly different from the proportions of naṏve or control moths completing these behaviors. However, the mean duration of sustained ßights of lure-preexposed male G. molesta in plumes generated by a lure was signiÞcantly shorter 15 min and 24 h after preexposure compared with that of naṏve moths. The proportion of male G. molesta contacting lures 15 min and 24 h after preexposure to ropes was not statistically different from the proportions of naṏve or control moths contacting the lure or orienting without source contact. However, as observed with moths preexposed to a lure, the mean duration of sustained ßights of male G. molesta preexposed to an Isomate-M Rosso dispenser was signiÞcantly shorter than that of naṏve moths 15 min and 24 h after preexposure. Mean durations of sustained ßights of male G. molesta preexposed to a lure or rope were signiÞcantly longer after 24 h compared with 15 min after the exposure treatment, indicating that the effect of pheromone preexposure decayed over time. Electroantennograms recorded 15 min and 24 h after preexposures to lures or Isomate-M Rosso dispensers in the ßight tunnel were indistinguishable from those recorded from unexposed moths. We suggest that false-plume following by naṏve male G. molesta combined with decreases in duration of subsequent anemotactic orientations after previous bouts of false-plume following may explain why Isomate-M Rosso dispensers are effective in mating disruption experiments with G. molesta.
Journal of Insect Behavior, 2000
Brief exposures of male Choristoneura rosaceana and Argyrotaenia velutinana to the plumes generated by lures releasing 3-component pheromone blends specifically tuned for each species or by commercially distributed Isomate OBLR/PLR Plus pheromone "rope" dispensers induced markedly different subsequent behavioral responses to pheromone. A greater proportion of C. rosaceana males took flight and successfully oriented toward lures 24 h after preexposure to a lure, a rope, or the lure-rope combination in a sustainedflight wind tunnel compared to naïve moths. Flights were also longer for preexposed than naïve moths. Preexposed male C. rosaceana were not more likely to fly toward ropes 24 h after preexposure. By contrast, fewer male A. velutinana oriented to lures 24 h after preexposure than did naïve moths. Those preexposed A. velutinana successfully locking onto plumes from lures flew for significantly shorter intervals than did unexposed moths. Electroantennograms revealed no changes at the periphery 15 min and 24 h after preexposure. For A. velutinana, the long-lasting effect was decreased attraction to a lure and increased attraction to a rope. For C. rosaceana, pheromone preexposure increased responsiveness to its authentic blend. This behavioral evidence
Journal of Chemical Ecology, 2006
The effect of brief pheromone exposures on responses of codling moth (Cydia pomonella L.) males was tested by flight-tunnel and electroantennogram (EAG) studies. Males were preexposed to pheromone for up to 3 min as they sat in release cages or for shorter times (a few seconds to several min) upon initiating flights or orienting in plumes. Brief exposures to Isomate-C Plus dispensers nearly eliminated moth orientations to 0.1 mg codlemone [(E,E)-8,10-dodecadien-1-ol] and 0.1 mg three-component (codlemone/12OH/14OH, 100:20:5 ratio) lures 15 min later. However, there was no associated change in EAG responses between preexposed and control moths. Behavioral responses of Isomate-C Plus-exposed males were normal 24 hr following exposure. The reduced sexual responsiveness observed following exposure to Isomate dispensers appeared to be associated with an elevation of response threshold. Brief preexposure to 0.1 mg codlemone and three-component lures also reduced orientational behavior of males 15 min later, but to a lesser degree than when preexposed to Isomate-C Plus dispensers. Male behavior following preexposure to a 0.1 mg codlemone/pear ester [(2E,4Z)-2,4decadienoate] lure (1:1 ratio) was no different from exposure to codlemone only. Orientational disruption in plots treated with 10 dispensers of Isomate-C Plus per tree was 88.3 and 95.9% for 1.0 and 0.1 mg codlemone lures, respectively. Some males did orient to 0.1 mg codlemone lures so we caution that flight-tunnel experiments on preexposure may overestimate the actual pheromone exposure dosage received by feral moths in treated orchards. Importantly, this work documents that a portion of feral males within a population has the capacity to overcome communicational disruption by high densities of Isomate-C Plus dispensers.
Physiological Entomology, 1984
When male oriental fruit moths, Grapholita molesta (Busck) (Tortricidae), casting in clean air entered an airstream permeated with pheromone their flight tracks changed immediately on initial contact with pheromone, but after a few seconds returned to casting as if in clean air. The degree of change in the flight track was directly related to the concentration of pheromone Although little net uptunnel movement occurred in response to the continuous stimulation provided by a uniformly permeated airstream, when an intermittent stimulus provided by a point-source plume was superimposed onto the permeated airstream moths were able to 'lock on' and zigzag uptunnel in the plume. The percentage of moths doing so corresponded to the difference between the peak concentration within the plume and the background concentration of pheromone permeating the airstream Moths also locked onto, and flew upwind along the pheromoneclean-air boundary formed along a pheromone-permeated side corridor Because a similai Iesponse was observed along a horizontal edge between a pheromone-permeated floor corridor and clean air, we conclude that the intermittent stimulation at the edge perpetuated the narrow zigzagging response to pheromone Introduction
Annals of the Entomological Society of America, 2006
and behavioral responses of female oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), were studied using the synthetic major component, (Z)-8-dodecenyl acetate, and partial three-component blend, (Z)-8-dodecenyl-acetate: (E)-8-dodecenyl-acetate:(Z)-8-dodecenol (in a 93:6:1 ratio), of the sex pheromone. EAGs elicited by both the single and three-component pheromone were signiÞcantly greater compared with hexane solvent controls. In 1-liter plastic chambers with constant throughput of air (50 ml/min) over rubber septa loaded with 0.01 or 0.1 mg of the three-component pheromone blend, onset of female calling was advanced by Ϸ2 h compared with solvent controls. However, the total number of females calling at peak time and the time of calling termination did not differ between pheromone-exposed and control moths. Oviposition rates of pheromone-exposed and clean air-exposed mated female moths did not differ in similar 1-liter ßow-through chambers lined with wax paper over 24-h intervals. In a separate experiment, male and female oriental fruit moth, caged in perforated 1-liter containers allowing air ventilation, were placed for 1-wk intervals in replicated glasshouses that were either treated with Isomate dispensers hung 0.5 m from chambers or left untreated. Oviposition rates between Isomate dispenser-exposed and control moths were similar. Female sensitivity to sex pheromone, termed "autodetection," has been observed previously and is thought to function either as a mechanism to 1) advance female calling periodicity under high population densities to increase the probability of attracting males, 2) induce dispersal under high population densities to reduce competition for males or food resources, or 3) aggregate females to increase local probability of mating success. Autodetection also may affect the efÞcacy of mating disruption for oriental fruit moth depending on whether pheromone exposure affects the diel periodicity of male sexual response.
Journal of Chemical Ecology, 2006
Eleven out of 13 disruption profiles (plots of dispenser density vs. male catch) from moth sex pheromone literature were consistent with a competitive-attraction mechanism, in which dispensers attract males and thereby divert them from females. Mean dispenser activity (D a ) across all competitive-attraction cases was 0.04 ± 0.06 (SD); values ranged from 0.0005 for a tiny laminated flake dispenser of racemic disparlure targeting gypsy moth to 0.2 for polyethylene tube dispensers used against lightbrown apple moth. A dispenser application activity (D Aa ) can be calculated by multiplying D a by the number of such dispensers applied per hectare of crop. The highest dispenser application activity (D Aa ) values approached 200 and corresponded to > 99% inhibition of catches of male moths in monitoring traps. Relative to the D Aa scale, % inhibition of catches of male moths compressed and obscured large differences in D Aa when % disruption exceeded 90%. For cases of competitive attraction, these two efficacy scales can be interconverted by using the formula: D Aa % 100= 100 minus % disruption ð Þ . When disruptive point sources of pheromone were directly observed, male moths were seen approaching pheromone dispensers whose disruption profiles matched competitive attraction. Two cases fit noncompetitive disruption mechanisms, which include camouflage, desensitization (adaptation and/or habituation), and sensory imbalance. In these cases, pheromone was released at rates higher than for cases of disruption by competitive attraction. Practical ramifications of the finding that competitive attraction appears to be the prevalent mechanism for moth mating Present address: disruption by pheromone point sources are listed. We believe that the congruence of diverse sets of mating disruption field data with explicit a priori predictions validates competitiveattraction theory. The analytical tools and principles governing competitive attraction that were uncovered during this study of mating disruption of moths should be generally applicable to competitive-attraction phenomena.
Elevation of pheromone response threshold in almond moth males pre-exposed to pheromone spray
Physiological Entomology, 1996
High percentages of naive Cudru cuutella (Walker) (Lepidoptera: Pyralidae) males not pre-exposed to pheromone flew upwind to sources containing 50 ng (83%) and 500 ng (97%) of pheromone, but not to sources containing 5 pg (23%) and 50 pg (4%). Of the naive males that flew upwind in response to 50 ng sources, 67% located and landed on the source, whereas fewer than 19% of the naive males that flew upwind in response to higher doses located and landed on the sources. A 2-minute pre-exposure of Ccuutella males to a spray cloud containing 50 ng, 500 ng, 5 pg or 50 pg of pheromone, induced shifts in response levels such that in wind-tunnel bioassays performed 1 h later, there was an increase in the doses that optimally elicited upwind flight and landing on the source that was proportional to the pre-exposure dose. Few of the pre-exposed males flew upwind to (1 0 4 3 %) an$ landed on (0-33%) 50 ng sources, whereas they now perferentially flew upwind to (58-81% and 52-73%) and landed on (33-68% and 55-60%) pheromone sources of doses of 500 ng and 5 pg, respectively. Therefore preexposure to pheromone promoted a shift of threshold for response, and not an overall reduction in responsiveness to pheromone.
Journal of Insect Behavior, 1992
The effects of prior pheromonal experience upon the pheromone- mediated upwind flight response was examined in the oriental fruit moth, Grapholita molesta(Busck) (Lepidoptera: Tortricidae). Adult male G. molestawere subjected to a parallel series of staggered and repeated pheromonal exposures in a sustained-flight wind tunnel. Levels of response to pheromone in male G. molestasignificantly decreased in a (a) rectilinear function with increased ages of individuals, (b) logarithmic function of successive trials, and (c) steeper logarithmic function of successive trials with increased dosage of sex pheromone. The baseline levels of responding were not affected by either the (a) dosage of sex pheromone, (b) posteclosion ages of individuals for their initial exposures once the main effect of age itself was estimated, (c) elapsed time in hours between trials, or (d) discrete days of testing as integral intervals, disregarding hours within days.
European Journal of …, 2007
Studies were conducted investigating the responses of female obliquebanded leafrollers, Choristoneura rosaceana (Harris) and redbanded leafrollers, Argyrotaenia velutinana (Walker) (Lepidoptera: Tortricidae), to components of their sex pheromone. Electroantennogram (EAG) recordings revealed significant responses from antennae of female moths of both species to the major pheromone component, (Z)-11-tetradecenyl acetate, at dosages ranging from 2 µg-2 mg. However, tested individually, the minor pheromone components of the obliquebanded leafroller, (E)-11-tetradecenyl acetate and (Z)-11-tetradecenol, elicited little or no antennal response from conspecific females. This result was consistent for redbanded leafroller females, which showed only weak responses to the minor component (E)-11-tetradecenyl acetate at a 2 mg dosage. For both species, species-specific blend ratios of the Z and E isomers of tetradecenyl acetate did not elicit a greater antennal response than the Z isomer alone. Virgin females of each species (2-4 d old) were placed into 1-liter plastic assay chambers with constant throughput of carbon-filtered air passed through 1-liter flasks containing rubber septa loaded with (Z)-and (E)-11-tetradecenyl acetates and (Z)-11-tetradecenol for trials with female obliquebanded leafrollers or with (Z)-and (E)-11-tetradecenyl acetates and dodecyl acetate for trials with female redbanded leafrollers. Exposure to pheromone-permeated air delayed the onset of calling by 1 h and terminated the calling period 1 h earlier for both species compared with solvent-control exposed females. Furthermore, the total proportion of calling females was reduced by half in chambers receiving constant throughput of pheromone-permeated air compared with solvent controls. Exposure to pheromonepermeated air also significantly reduced egg-laying in both species compared with clean-air controls. Furthermore, application of the major pheromone component, (Z)-11-tetradecenyl acetate, at dosages ranging from 2 µg-2 mg to wax-paper ovipositional substrates, deterred oviposition by females of both species. Our data suggest that application of synthetic sex-attractant pheromones for mating disruption of leafroller species may have deleterious effects on female moth behavior, which may contribute to pest control. Field investigations will need to be conducted to test this hypothesis.
Journal of Chemical Ecology, 1985
The response of individual male turnip moths Agrotis segetum was observed in a sustained flight tunnel to a mixture of decyl acetate, (Z)-5decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate in proportions similar to those found in gland extracts from virgin females (0.6 : 1 : 5 : 2.5). Lures containing 3-30/~g (Z)-5-decenyl acetate proved to be maximally attractive, with approximately 60% of the males completing all behavioral steps from activation to copulation efforts. A 300-/xg dosage caused significant arrestment of upwind flight. Peak response to synthetics, however, was significantly lower than to female glands. Omitting decyl acetate from the blend did not affect the activity, while omission of any of the three monounsaturated acetates caused a dramatic decrease in response. In the field maximum trap catches were achieved with 1-to 30-#g lures. The subtractive assay carried out in the field confirmed the neutrality of decyl acetate and the importance of the three monoenes. Adding 1% of (Z)-8-dodecenyl acetate (earlier reported as an "inhibitor") to the four-component mixture decreased the trap catch to about 50%, and increasing the amount of (Z)-8-dodecenyl acetate to 27% decreased the activity further to about 10%. (Z)-8-Dodecenyl acetate also decreased the number of successful flights in the flight tunnel.