Pheromone Plume Research Articles

Evidence of active or passive downwind dispersal in mark–release–recapture of moths

AbstractModelling moth dispersal in relation to wind direction and strength could greatly enhance the role of pheromone traps in biosecurity and pest management applications. Anemotaxis theory, which describes moth behaviour in the presence of a pheromone plume and is used as a framework for such models. Currently, however, that theory includes only three components: upwind, zigzagging, and sideways casting behaviour. We test anemotaxis theory by analysing the data from a series of mark–release–recapture experiments where the wind direction was known and the insects were trapped using an irregular grid of pheromone traps. The trapping results provide evidence of a downwind component to the flight patterns of the released insects. This active or passive downwind dispersal is likely to be an appetitive behaviour, occurring prior to the elicitation of pheromone‐oriented flight patterns (pheromone anemotaxis). Given the potential for significant displacement during downwind dispersal, this component will have impact on final trap captures and should be considered when constructing moth dispersal models.

Visual stimuli induced by self-motion and object-motion modify odour-guided flight of male moths (Manduca sexta L.)

Animals rely on multimodal sensory integration for proper orientation within their environment. For example, odour-guided behaviours often require appropriate integration of concurrent visual cues. To gain a further understanding of mechanisms underlying sensory integration in odour-guided behaviour, our study examined the effects of visual stimuli induced by self-motion and object-motion on odour-guided flight in male M. sexta. By placing stationary objects (pillars) on either side of a female pheromone plume, moths produced self-induced visual motion during odour-guided flight. These flights showed a reduction in both ground and flight speeds and inter-turn interval when compared with flight tracks without stationary objects. Presentation of an approaching 20 cm disc, to simulate object-motion, resulted in interrupted odour-guided flight and changes in flight direction away from the pheromone source. Modifications of odour-guided flight behaviour in the presence of stationary objects suggest that visual information, in conjunction with olfactory cues, can be used to control the rate of counter-turning. We suggest that the behavioural responses to visual stimuli induced by object-motion indicate the presence of a neural circuit that relays visual information to initiate escape responses. These behavioural responses also suggest the presence of a sensory conflict requiring a trade-off between olfactory and visually driven behaviours. The mechanisms underlying olfactory and visual integration are discussed in the context of these behavioural responses.

Detection and Discrimination of Mixed Odor Strands in Overlapping Plumes Using an Insect-Antenna-Based Chemosensor System

Olfactory signals, a major means of communication in insects, travel in the form of turbulent odor plumes. In terrestrial environments, an odor blend emitted from a single point source exists in every strand of the plume, whereas, in confluent plumes from two different odor sources, the strands have some chance of being coincident and comprising a new third odor in those strands. Insects have the ability to detect and interpret necessary olfactory information from individual filamentous odor strands in complex multifilament odor plumes. However, behaviorists have had no way to measure the stimulus situations they are presenting to their temporally acute insect subjects when performing Y-tube olfactometer or confluent pheromone plume wind tunnel assays. We have successfully measured the degree of plume-strand mixing in confluent plumes in a wind tunnel by using a multichannel insect-antenna-based chemosensor. A PC-based computer algorithm to analyze antennal signals from the probe portion of the system performed real-time signal processing and, following a short training session, classified individual odorant/mixture strands at sub-second temporal resolution and a few tens of millimeters of spatial resolution. In our studies, the chemosensor classified a higher frequency of strands of two different odorants emitted from two closely spaced filter papers as being "mixed" when the sources were located only 1 or 2 cm apart than when the sources were 5 or 10 cm apart. These experiments demonstrate the chemosensor's potential to be used for measuring odor stimulus situations in more complex multiple-plume environments.

Male position and calling effort together influence male attractiveness in leks of the medfly, Ceratitis capitata (Diptera: Tephritidae)

Despite the close association between lek mating systems and the study of female mate choice, male mating success in leks is often associated with other aspects of sexual selection as well as female choice of male display traits. Males of the medfly Ceratitis capitata form leks on the undersides of leaves of their host plants. By experimentally creating artificial leks, we show that male success at attracting females depends not only on male calling effort (pheromone production dispersed by wing movement), but also on the position of the male within a lek. Males in the highest position in the artificial lek (closest to the light) attracted more females, and received more visits from those females. In our experiment, we deliberately minimized the visual cues that females approaching a male could use and, under these conditions, found no associations between male attractiveness and male size, weight or fluctuating asymmetry, either of the wings or sex setae (a pair of bilateral supra-fronto-orbital bristles). The latter result contrasts with earlier studies showing a significant negative association between sex setae fluctuating asymmetry and mating success. Accordingly, we conclude that symmetry of the male sex setae has no role in nonvisual communication (e.g. through directing pheromone plumes). Mating patterns associated with this insect are therefore every bit as complex as those in vertebrate leks. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95, 479–487.

Effects of altering flow and odor information on plume tracking behavior in walking cockroaches, Periplaneta americana (L.)

Animals using odor plumes to locate resources are activated to track these plumes by the presence of an attractive odor, and typically steer toward the source using directional cues from the flowing air or water bearing the odor. We challenged freely walking virgin male cockroaches, Periplaneta americana, to track plumes of airborne female pheromone and then video-recorded and analyzed their responses as the odor plume and wind were independently manipulated. Plume tracking males that experienced the total loss of directional air flow halfway to the odor source showed little change in their performance, and 100% were able to quickly locate the pheromone source. By contrast, males experiencing a sudden loss of odor while tracking a plume rapidly changed their behavior; often turning downwind and retracing their steps to the release point, or walking in loops, but rarely moving upwind to the previous location of the source. In a subsequent experiment, in order to determine whether a memory of the previously experienced wind direction could provide the directional information necessary to locate an odor source, we challenged males to track plumes in zero wind after pre-exposing them to: (1) wind and pheromone, (2) wind only, and (3) neither wind nor pheromone. These were compared to males tracking a wind-borne pheromone plume, in which case, all males were able to locate the pheromone source. Our results show that males require the detection of wind and pheromone simultaneously during plume tracking in order to quickly and efficiently locate the odor source. These results are consistent with those reported from flying moths tracking wind-borne pheromone plumes, and suggest that the control system underlying this behavior requires ongoing simultaneous experience with wind and odor information during the performance of the behavior to operate efficiently.

Active Space of Pheromone Plume and its Relationship to Effective Attraction Radius in Applied Models

The release rate of a semiochemical lure that attracts flying insects has a specific effective attraction radius (EAR) that corresponds to the lure's orientation response strength. EAR is defined as the radius of a passive sphere that intercepts the same number of insects as a semiochemical-baited trap. It is estimated by calculating the ratio of trap catches in the field in baited and unbaited traps and the interception area of the unbaited trap. EAR serves as a standardized method for comparing the attractive strengths of lures that is independent of population density. In two-dimensional encounter rate models that are used to describe insect mass trapping and mating disruption, a circular EAR (EAR(c)) describes a key parameter that affects catch or influence by pheromone in the models. However, the spherical EAR, as measured in the field, should be transformed to an EAR(c) for appropriate predictions in such models. The EAR(c) is calculated as (pi/2EAR(2))/F (L), where F (L) is the effective thickness of the flight layer where the insect searches. F (L) was estimated from catches of insects (42 species in the orders Coleoptera, Lepidoptera, Diptera, Hemiptera, and Thysanoptera) on traps at various heights as reported in the literature. The EAR(c) was proposed further as a simple but equivalent alternative to simulations of highly complex active-space plumes with variable response surfaces that have proven exceedingly difficult to quantify in nature. This hypothesis was explored in simulations where flying insects, represented as coordinate points, moved about in a correlated random walk in an area that contained a pheromone plume, represented as a sector of active space composed of a capture probability surface of variable complexity. In this plume model, catch was monitored at a constant density of flying insects and then compared to simulations in which a circular EAR(c) was enlarged until an equivalent rate was caught. This demonstrated that there is a circular EAR(c), where all insects that enter are caught, which corresponds in catch effect to any plume. Thus, the EAR(c), based on the field-observed EAR, can be used in encounter rate models to develop effective control programs based on mass trapping and/or mating disruption.

Interspecific Pheromone Plume Interference Among Sympatric Heliothine Moths: A Wind Tunnel Test Using Live, Calling Females

Three species of North American heliothine moths were used to determine the level at which interspecific female interference of male attraction to conspecific females occurs. We used live calling females of Heliothis virescens, H. subflexa, and Helicoverpa zea, as lures for conspecific males in a wind tunnel, and then placed heterospecific females on either side of the original species such that the plumes of the three females overlapped downwind. In nearly all combinations, in the presence of heterospecific females, fewer males flew upwind and contacted or courted the source than when only conspecific females were used in the same spatial arrangement. Males did not initiate upwind flight to solely heterospecific female arrangements. Our results show that the naturally emitted pheromone plumes from heterospecific females of these three species can interfere with the ability of females to attract conspecific males when multiple females are in close proximity. However, the fact that some males still located their calling, conspecific females attests to the ability of these male moths to discriminate point source odors by processing the conflicting information from interleaved strands of attractive and antagonistic odor filaments on a split-second basis.

Efficient Olfactory Coding in the Pheromone Receptor Neuron of a Moth

The concept of coding efficiency holds that sensory neurons are adapted, through both evolutionary and developmental processes, to the statistical characteristics of their natural stimulus. Encouraged by the successful invocation of this principle to predict how neurons encode natural auditory and visual stimuli, we attempted its application to olfactory neurons. The pheromone receptor neuron of the male moth Antheraea polyphemus, for which quantitative properties of both the natural stimulus and the reception processes are available, was selected. We predicted several characteristics that the pheromone plume should possess under the hypothesis that the receptors perform optimally, i.e., transfer as much information on the stimulus per unit time as possible. Our results demonstrate that the statistical characteristics of the predicted stimulus, e.g., the probability distribution function of the stimulus concentration, the spectral density function of the stimulation course, and the intermittency, are in good agreement with those measured experimentally in the field. These results should stimulate further quantitative studies on the evolutionary adaptation of olfactory nervous systems to odorant plumes and on the plume characteristics that are most informative for the ‘sniffer’. Both aspects are relevant to the design of olfactory sensors for odour-tracking robots.

Dynamic properties of Drosophila olfactory electroantennograms

Time-dependent properties of chemical signals are probably crucially important to many animals, but little is known about the dynamics of chemoreceptors. Behavioral evidence of dynamic sensitivity includes the control of moth flight by pheromone plume structure, and the ability of some blood-sucking insects to detect varying concentrations of carbon dioxide, possibly matched to host breathing rates. Measurement of chemoreceptor dynamics has been limited by the technical challenge of producing controlled, accurate modulation of olfactory and gustatory chemical concentrations over suitably wide ranges of amplitude and frequency. We used a new servo-controlled laminar flow system, combined with photoionization detection of surrogate tracer gas, to characterize electroantennograms (EAG) of Drosophila antennae during stimulation with fruit odorants or aggregation pheromone in air. Frequency response functions and coherence functions measured over a bandwidth of 0-100 Hz were well characterized by first-order low-pass linear filter functions. Filter time constant varied over almost a tenfold range, and was characteristic for each odorant, indicating that several dynamically different chemotransduction mechanisms are present. Pheromone response was delayed relative to fruit odors. Amplitude of response, and consequently signal-to-noise ratio, also varied consistently with different compounds. Accurate dynamic characterization promises to provide important new information about chemotransduction and odorant-stimulated behavior.

Simulation of Mating Disruption and Mass Trapping with Competitive Attraction and Camouflage

Simulation models of mass trapping and mating disruption were developed based on correlated random walks (CRW) of flying male moths searching for females. Males encountered pheromone plumes, transformed into a circular probability surface represented as an effective attraction radius (EAR), from females and from dispensers with or without traps. In simulations, parameters of dispenser EAR and density, female EAR and density, female stationary periods, male density, and male orienting times in EAR of dispensers or females were varied, whereas the male CRW parameters (speed, turning angle, and step size) remained constant to evaluate effects on the percentages of females mating. When male orienting time was constant regardless of EAR, the models indicated no difference in mating disruption efficacy between either a higher density of dispensers with smaller EAR or a lower density of dispensers with a compensating larger EAR. However, when the orienting time was increased in proportion to dispenser EAR, fewer dispensers with larger EAR were more effective in reducing female mating than were more numerous ones with smaller EAR. When costs of pheromone are substantial, however, more numerous dispensers of smaller EAR would be more economical because dose-response curves in previous studies indicate release rate must increase exponentially to achieve a linear increase in EAR. The models are useful in understanding the variables affecting the success of insect control programs. More precise measurements of the above parameters in the field are needed before the models can precisely predict outcomes of mating disruption and mass trapping.

Listening in Pheromone Plumes: Disruption of Olfactory-Guided Mate Attraction in a Moth by a Bat-Like Ultrasound

Nocturnal moths often use sex pheromones to find mates and ultrasonic hearing to evade echolocating bat predators. Male moths, when confronted with both pheromones and sound, thus have to trade off reproduction and predator avoidance depending on the relative strengths of the perceived conflicting stimuli. The ultrasonic hearing of Plodia interpunctella was investigated. A threshold curve for evasive reaction to ultrasound of tethered moths was established, and the frequency of best hearing was found to be between 40 and 70 kHz. Flight tunnel experiments were performed where males orienting in a sex pheromone plume were stimulated with 50 kHz pulses of different intensities. Pheromone-stimulated males showed increased defensive response with increased intensity of the sound stimulus, and the acoustic cue had long-lasting effects on their pheromone-mediated flight, revealing a cost associated with vital evasive behaviours.

Analysis and Manipulation of the Structure of Odor Plumes from a Piezo-Electric Release System and Measurements of Upwind Flight of Male Almond Moths, Cadra cautella, to Pheromone Plumes

We investigated the plume structure of a piezo-electric sprayer system, set up to release ethanol in a wind tunnel, using a fast response mini-photoionizaton detector. We recorded the plume structure of four different piezo-sprayer configurations: the sprayer alone; with a 1.6-mm steel mesh shield; with a 3.2-mm steel mesh shield; and with a 5 cm circular upwind baffle. We measured a 12 x 12-mm core at the center of the plume, and both a horizontal and vertical cross-section of the plume, all at 100-, 200-, and 400-mm downwind of the odor source. Significant differences in plume structure were found among all configurations in terms of conditional relative mean concentration, intermittency, ratio of peak concentration to conditional mean concentration, and cross-sectional area of the plume. We then measured the flight responses of the almond moth, Cadra cautella, to odor plumes generated with the sprayer alone, and with the upwind baffle piezo-sprayer configuration, releasing a 13:1 ratio of (9Z,12E)-tetradecadienyl acetate and (Z)-9-tetradecenyl acetate diluted in ethanol at release rates of 1, 10, 100, and 1,000 pg/min. For each configuration, differences in pheromone release rate resulted in significant differences in the proportions of moths performing oriented flight and landing behaviors. Additionally, there were apparent differences in the moths' behaviors between the two sprayer configurations, although this requires confirmation with further experiments. This study provides evidence that both pheromone concentration and plume structure affect moth orientation behavior and demonstrates that care is needed when setting up experiments that use a piezo-electric release system to ensure the optimal conditions for behavioral observations.

High individual variation in pheromone production by tree-killing bark beetles (Coleoptera: Curculionidae: Scolytinae)

Aggregation via pheromone signalling is essential for tree-killing bark beetles to overcome tree defenses and reproduce within hosts. Pheromone production is a trait that is linked to fitness, so high individual variation is paradoxical. One explanation is that the technique of measuring static pheromone pools overestimates true variation among individuals. An alternative hypothesis is that aggregation behaviour dilutes the contribution of individuals to the trait under selection and reduces the efficacy of natural selection on pheromone production by individuals. We compared pheromone measurements from traditional hindgut extractions of female southern pine beetles with those obtained by aerating individuals till they died. Aerations showed greater total pheromone production than hindgut extractions, but coefficients of variation (CV) remained high (60-182%) regardless of collection technique. This leaves the puzzle of high variation unresolved. A novel but simple explanation emerges from considering bark beetle aggregation behaviour. The phenotype visible to natural selection is the collective pheromone plume from hundreds of colonisers. The influence of a single beetle on this plume is enhanced by high variation among individuals but constrained by large group sizes. We estimated the average contribution of an individual to the pheromone plume across a range of aggregation sizes and showed that large aggregation sizes typical in mass attacks limit the potential of natural selection because each individual has so little effect on the overall plume. Genetic variation in pheromone production could accumulate via mutation and recombination, despite strong effects of the pheromone plume on the fitness of individuals within the aggregation. Thus, aggregation behaviour, by limiting the efficacy of natural selection, can allow the persistence of extreme phenotypes in nature.

Position Around A Tree: Consequences For Pheromone Detection

The air flow pattern expected around a cylindrical object such as a tree in slow wind, is predicted from fluid mechanics to have areas of faster flow (upwind) and slower recirculating flow with eddies (downwind). An organism located on the surface of a tree would experience different flow depending on its circumferential position. If that organism was searching for a chemical signal, such as a pheromone plume, it might maximize its probability of chemodetection by placing itself in areas of greatest flow speed (the upwind surface of the cylinder, i.e., in front of the separation points). We tested whether wood cockroaches in the genus Parcoblatta exhibit such upwind positioning; they live in forests, and males actively fly from tree to tree, while searching for females releasing sex pheromone. In contrast to an expectation of upwind preference, male cockroaches were evenly distributed around trees relative to upwind (measured with a novel "feather boa" flow visualization technique), even though the wind direction was relatively steady. We investigated whether sex pheromone could be detected at any location around a cylindrical surface in a laboratory flow chamber by using Bombyx mori wing fanning as a bioassay. Although upwind moths arrayed on the surface detected pheromone more rapidly, pheromone detection occurred at least a third of the time at any position, which could explain the even distribution of Parcoblatta males around trees.

Differential impacts of the southern pine beetle, Dendroctonus frontalis, on Pinus palustris and Pinus taeda

Patterns of host use by herbivore pests can have serious consequences for natural and managed ecosystems but are often poorly understood. Here, we provide the first quantification of large differential impacts of the southern pine beetle, Dendroctonus frontalis Zimmermann, on loblolly pine, Pinus taeda L., and longleaf pine, Pinus palustris P. Mill., and evaluate putative mechanisms for the disparity. Spatially extensive survey data from recent epidemics indicate that, per square kilometre, stands of loblolly versus longleaf pine in four forests (380–1273 km2) sustained 3–18 times more local infestations and 3–116 times more tree mortality. Differences were not attributable to size or age structure of pine stands. Using pheromone-baited traps, we found no differences in the abundance of dispersing D. frontalis or its predator Thanasimus dubius Fabricius between loblolly and longleaf stands. Trapping triggered numerous attacks on trees, but the pine species did not differ in the probability of attack initiation or in the surface area of bark attacked by growing aggregations. We found no evidence for postaggregation mechanisms of discrimination or differential success on the two hosts, suggesting that early colonizers discriminate between host species before a pheromone plume is present.

A Specific Male Olfactory Sensillum Detects Behaviorally Antagonistic Hairpencil Odorants

Within insect species, olfactory signals play a vital role in communication, particularly in the context of mating. During courtship, males of many moth species release pheromones that function as aphrodisiacs for conspecific females, or repellants to competing conspecific males. The physiology and antennal lobe projections are described of olfactory receptor neurons within an antennal sensillum present on male Heliothis virescens F. (Lepidoptera: Noctuidae) moths sensitive to conspecific male H. virescens-produced pheromone components. Olfactory receptor neurons responded to hexadecanyl acetate and octadecanyl acetate hairpencil components, and Z11-hexadecenyl acetate, an odorant used by closely related heliothine species in their female produced pheromone, which is antagonistic to male H. virescens responses. This acetate-sensitive sensillum appears homologous to a sensillum type previously described in females of this species, sharing similar physiology and glomerular projection targets within the antennal lobe. Wind tunnel observations indicate that H. virescens hairpencil odors (hexadecanyl acetate, octadecanyl acetate) function to antagonize responses of conspecific males following a female sex pheromone plume. Thus, male-male flight antagonism in H. virescens appears to be mediated by this particular sensillum type.

Field electroantennogram and trap assessments of aerosol pheromone dispensers for disrupting mating in Epiphyas postvittana

An electronically controlled aerosol system for mating disruption was evaluated against Epiphyas postvittana Walker in apple orchards in New Zealand. The area in which male moths were affected by the aerosol system was examined using catches in traps radiating from a central single-point source of either one aerosol can dispenser or 100 polyethylene tubing dispensers, compared with catches in orchard plots without pheromone dispensers. Both pheromone dispensing systems decreased moth catch to similar levels at 5-10 m from the central release point, but there was 5.5-fold more pheromone released from aerosol cans than from polyethylene dispensers over a 24 h period. Trap catches were reduced by about 90% in plots treated with either five aerosol cans per hectare or uniform deployment of polyethylene dispensers. Recordings of electroantennograms in open grassed plots and orchards indicated that the treated cotton pad of an aerosol dispenser and a point source of 100 polyethylene tubing dispensers produced similar electroantennogram recordings. Electroantennogram recordings provided evidence that pheromone plume detection from a single-point source was maintained over a range of 5-40 m downwind in the orchard. On present evidence, aerosol pheromone dispensers could not be recommended for further testing towards control of E. postvittana under New Zealand conditions owing to their higher cost of purchase and operation.

Grandlure Dosage and Attraction of Boll Weevils (Coleoptera: Curculionidae)

The effects of grandlure dosage on of boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), attraction were assessed. Traps collected more boll weevils under field and laboratory conditions as the amount of grandlure in laminated plastic strips was increased from 0 to 10, 30, and 60 mg. Spreading the point source of the lure by cutting the strip into quarters and positioning each quarter on separate corners of the large capacity trap to create an expanded source for the pheromone plume, however, resulted in fewer trap captures than traps with quartered lures all positioned on a single corner. The large capacity trap with the quartered lure on one corner also caught more weevils than the traps with an intact lure fastened to one corner. Although aging lure strips for three weeks reduced emissions of the four pheromone components and their attractiveness to boll weevils, cutting the aged lure into quarters resulted in greater emissions and attraction than lures that were aged intact or as quarters. Some pheromone components volatilized faster than others, resulting in time-related changes in blend ratios, but the underlying factor in boll weevil attraction to grandlure strips was dosage, the amount of volatilized pheromone available for interacting with an adult boll weevil.

Grandlure Dosage and Attraction of Boll Weevils (Coleoptera: Curculionidae)

The effects of grandlure dosage on of boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), attraction were assessed. Traps collected more boll weevils under field and laboratory conditions as the amount of grandlure in laminated plastic strips was increased from 0 to 10, 30, and 60 mg. Spreading the point source of the lure by cutting the strip into quarters and positioning each quarter on separate corners of the large capacity trap to create an expanded source for the pheromone plume, however, resulted in fewer trap captures than traps with quartered lures all positioned on a single corner. The large capacity trap with the quartered lure on one corner also caught more weevils than the traps with an intact lure fastened to one corner. Although aging lure strips for three weeks reduced emissions of the four pheromone components and their attractiveness to boll weevils, cutting the aged lure into quarters resulted in greater emissions and attraction than lures that were aged intact or as quarters. Some pheromone components volatilized faster than others, resulting in time-related changes in blend ratios, but the underlying factor in boll weevil attraction to grandlure strips was dosage, the amount of volatilized pheromone available for interacting with an adult boll weevil.

Models for integrated pest management with chemicals in atmospheric surface layers

Surface layer landscapes are described by spatial distributions of canopy type and roughness, surface slopes and topography. Agricultural landscapes also include distributions of pests and pest management systems. Insect populations together with pheromone traps or dispensers constitute a system that depends on the airborne chemical ‘landscape’ shaped by the emissions and wind dispersal. Effective operation of such complex systems needs integrative tools comprising dynamic component modelling. We describe a linked modelling system which reduces uncertainty in monitoring for pest management. The spatial information from surface-layer landscapes and winds is integrated over multiple length and time scales. Larger scale meteorological flows ( ∼ 5 km) disperse pheromones from sources embedded in the surface layer canopy. Smaller scale plume properties ( ∼ 100 m), are downscaled even further to internal plume-fluctuation properties within the plumes ( ∼ 1 cm). Finally, the distributed plume properties are coupled with insect tracking models for pest distribution prediction. The model hierarchy is simple, with the key being the parameters that are passed from one model level to the next. Meteorological models, like the commercially available TAPM system, can model the weather, i.e. the broad scale mean flow over the terrain and determine the local stability over each surface type in the landscape. The complex chemical landscape within the wind fields in the surface layer can then be predicted with Lagrangian particle models of the dispersion of pheromone plumes from canopy releases. Such sources can be from either attracting females or synthetic disruption systems like traps. The internal structure within the plumes, generated by surface layer turbulence, is also explicitly linked with surface layer characteristics of the fine scale turbulence but at even smaller scales because of the tiny dimensions of the source. We adapt classic Monin–Obukhov similarity theory [Stull, R.B., 1988. An Introduction to Boundary Layer Meteorology. Kluwer Academic Publishers, Dordrecht, Netherlands] for modelling plume fluctuations and develop instantaneous random concentration field properties based on inertial range scaling of turbulent processes. The final component is an agent-based insect tracking model that couples directly to the local instantaneous chemical landscape. The intelligent agent makes navigation decisions based on chemical signals to home onto the target source. The coupled system provides an insect mating prediction that accounts for trap catch counts and the influence of weather and cropping systems on these processes. Studies with this model will ultimately allow for a more accurate inference from trap monitoring and for the better management of pests.