Navigation Along Windborne Plumes of Pheromone and Resource-Linked Odors

2021 ◽  
Vol 66 (1) ◽  
pp. 317-336
Author(s):  
Ring T. Cardé
Keyword(s):  
Behavioral Response ◽  
Scale Structure ◽  
Turbulent Structure ◽  
Odor Source ◽  
Fine Scale ◽  
Odor Concentration ◽  
Flying Insects ◽  
Odor Plumes ◽  
Clean Air ◽  
Sequential Measurements

Many insects locate resources such as a mate, a host, or food by flying upwind along the odor plumes that these resources emit to their source. A windborne plume has a turbulent structure comprised of odor filaments interspersed with clean air. As it propagates downwind, the plume becomes more dispersed and dilute, but filaments with concentrations above the threshold required to elicit a behavioral response from receiving organisms can persist for long distances. Flying insects orient along plumes by steering upwind, triggered by the optomotor reaction. Sequential measurements of differences in odor concentration are unreliable indicators of distance to or direction of the odor source. Plume intermittency and the plume's fine-scale structure can play a role in setting an insect's upwind course. The prowess of insects in navigating to odor sources has spawned bioinspired virtual models and even odor-seeking robots, although some of these approaches use mechanisms that are unnecessarily complex and probably exceed an insect's processing capabilities.

scholarly journals Odor source localization in complex visual environments by fruit flies

2017 ◽  
Author(s):  
Nitesh Saxena ◽  
Dinesh Natesan ◽  
Sanjay P. Sane
Keyword(s):  
Fruit Flies ◽  
Odor Source ◽  
High Contrast ◽  
Visual Landmarks ◽  
Visual Objects ◽  
Flying Insects ◽  
Air Stream ◽  
Odor Plumes ◽  
Odor Tracking ◽  
Tracking Behavior

AbstractFlying insects routinely forage in complex and cluttered sensory environments. Their search for a food or a pheromone source typically begins with a whiff of odor, which triggers a flight response, eventually bringing the insect in the vicinity of the odor source. The precise localization of an odor source, however, requires the use of both visual and olfactory modalities, aided by air currents that trap odor molecules into turbulent plumes, which the insects track. Here, we investigated odor tracking behavior in fruit flies (Drosophila melanogaster) presented with low- or high-contrast visual landmarks, which were either paired with or separate from an attractive odor cue. These experiments were conducted either in a gentle air stream which generated odor plumes, or in still air in which odor dissipates uniformly in all directions. The trajectories of the flies revealed several novel features of their odor-tracking behavior in addition to those that have been previously documented (e.g. cast- and-surge maneuvers). First, in both moving and still air, odor-seeking flies rely on the co-occurrence of visual landmarks with olfactory cues to guide them to putative odorant objects in the decisive phase before landing. Second, flies abruptly decelerate when they encounter an odor plume, and thereafter steer towards nearby visual objects that had no inherent salience in the absence of odor. This indicates that the interception of an attractive odor increases their salience to nearby high-contrast visual landmarks. Third, flies adopt distinct odor tracking strategies during flight in moving vs. still air. Whereas they weave in and out of plumes towards an odor source when airflow is present, their approach is more gradual and incremental in still air. Both strategies are robust and flexible, and can ensure that the flies reliably find the odor source under diverse visual and airflow environments. Our experiments also indicate the possibility of an olfactory “ working memory” that enables flies to continue their search even when the olfactory feedback is reduced or absent. Together, these results provide insights into how flies determine the precise location of an odor source.

scholarly journals Erratum: Polygamy and an absence of fine-scale structure in Dendroctonus ponderosae (Hopk.) (Coleoptera: Curcilionidae) confirmed using molecular markers

Heredity ◽  
2015 ◽  
Vol 116 (1) ◽  
pp. 124-124 ◽  
Author(s):  
J K Janes ◽  
A D Roe ◽  
A V Rice ◽  
J C Gorrell ◽  
D W Coltman ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Dendroctonus Ponderosae ◽  
Scale Structure ◽  
Fine Scale

scholarly journals Spatial odor discrimination in hawkmoth, Manduca sexta (L.)

2020 ◽  
Author(s):  
P. Kalyanasundaram ◽  
M. A. Willis
Keyword(s):  
Spatial Distribution ◽  
Manduca Sexta ◽  
Flight Control ◽  
Spatial Information ◽  
Egg Laying ◽  
Proboscis Extension Reflex ◽  
Flying Insects ◽  
Odor Learning ◽  
Odor Plumes ◽  
Proboscis Extension

AbstractFlying insects track turbulent odor plumes to find mates, food and egg-laying sites. To maintain contact with the plume, insects are thought to adapt their flight control according to the distribution of odor in the plume using the timing of odor onsets and intervals between odor encounters. Although timing cues are important, few studies have addressed whether insects are capable of deriving spatial information about odor distribution from bilateral comparisons between their antennae in flight. The proboscis extension reflex (PER) associative learning protocol, originally developed to study odor learning in honeybees, was modified to show hawkmoths, Manduca sexta, can discriminate between odor stimuli arriving on either antenna. We show moths discriminated the odor arrival side with an accuracy of >70%. The information about spatial distribution of odor stimuli is thus available to moths searching for odor sources, opening the possibility that they use both spatial and temporal odor information.

scholarly journals Fine‐scale structure among mesophotic populations of the great star coral Montastraea cavernosa revealed by SNP genotyping

2020 ◽  
Vol 10 (12) ◽  
pp. 6009-6019
Author(s):  
Crawford Drury ◽  
Rocío Pérez Portela ◽  
Xaymara M. Serrano ◽  
Marjorie Oleksiak ◽  
Andrew C. Baker
Keyword(s):  
Scale Structure ◽  
Snp Genotyping ◽  
Fine Scale ◽  
Montastraea Cavernosa

Experimental study of the fine-scale structure of conserved scalar mixing in turbulent shear flows. Part 1. Sc [Gt ] 1

1996 ◽  
Vol 317 ◽  
pp. 21-71 ◽  
Author(s):  
Kenneth A. Buch ◽  
Werner J. A. Dahm
Keyword(s):  
Strain Rate ◽  
Dissipation Rate ◽  
Shear Flows ◽  
Scale Structure ◽  
Scalar Dissipation ◽  
Turbulent Shear ◽  
Fine Scale ◽  
Scalar Dissipation Rate ◽  
Principal Axes ◽  
Turbulent Shear Flows

We present results from an experimental investigation into the fine-scale structure associated with the mixing of a dynamically passive conserved scalar quantity on the inner scales of turbulent shear flows. The present study was based on highly resolved two- and three-dimensional spatio-temporal imaging measurements. For the conditions studied, the Schmidt number (Sc ≡ v/D) was approximately 2000 and the local outerscale Reynolds number (Reσ≡ uσ/v) ranged from 2000 to 10000. The resolution and signal quality allow direct differentiation of the measured scalar field ζ(x, t) to give the instantaneous scalar energy dissipation rate field (Re Sc)−1 ∇ζċ∇ζ(x, t). The results show that the fine-scale structure of the scalar dissipation field, when viewed on the inner-flow scales for Sc ≡ 1, consists entirely of thin strained laminar sheet-like diffusion layers. The internal structure of these scalar dissipation sheets agrees with the one-dimensional self-similar solution for the local strain–diffusion competition in the presence of a spatially uniform but time-varying strain rate field. This similarity solution also shows that line-like structures in the scalar dissipation field decay exponentially in time, while in the vorticity field both line-like and sheet-like structures can be sustained. This sheet-like structure produces a high level of intermittency in the scalar dissipation field – at these conditions approximately 4% of the flow volume accounts for nearly 25% of the total mixing achieved. The scalar gradient vector field ∇ζ(x, t) for large Sc is found to be nearly isotropic, with a weak tendency for the dissipation sheets to align with the principal axes of the mean flow strain rate tensor. Joint probability densities of the conserved scalar and scalar dissipation rate have a shape consistent with this canonical layer-like fine-scale structure. Statistics of the conserved scalar and scalar dissipation rate fields are found to demonstrate similarity on inner-scale variables even at the relatively low Reynolds numbers investigated.

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