How insects track odors by navigating microscale winds
An optimal range of wind speed and environmental surface complexity may
help flying insects locate an odor source

Date:
May 30, 2023
Source:
American Institute of Physics
Summary:
Insects use odor plumes -- which travel like smoke and form when the
wind blows odor molecules from their source -- to track down sources
such as flowers or pheromones. But wind tunnels are typically
unable to replicate realistic outdoor wind conditions. Researchers
decided to explore microscale wind conditions in various outdoor
environments to better understand what flying insects might
experience while tracking odor plumes.


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FULL STORY ==========================================================================
How do flying insects like important pollinators locate odor sources
in the great outdoors, despite encountering highly variable wind
conditions? They use odor plumes -- which travel like smoke and form
when the wind blows odor molecules from their source -- to track down
sources such as flowers or pheromones.

But wind tunnels are typically unable to replicate realistic outdoor
wind conditions. In Physics of Fluids, by AIP Publishing, University of
Nevada at Reno researchers decided to explore microscale wind conditions
in various outdoor environments to better understand what flying insects
might experience while tracking odor plumes.

Authors Jaleesa Houle and Floris Van Breugel assessed the mechanical
turbulence produced by ambient wind flowing over surface roughness
elements such as buildings, trees, and fences and its role in odor
plume tracking.

"Since we're studying wind dynamics within the surface roughness sublayer,
most known atmospheric similarity theories that describe properties of
the wind profile are not applicable," said Houle. "So, we use statistical analysis to find both spatial and temporally significant correlations
between wind measurements for various sites where we collected data."
They collected near-surface wind data from several sage steppe
(shrub-filled grassland), forest, and urban areas in Northern Nevada
and discovered near- surface wind direction is often highly variable
over timescales of less than 10 minutes. They also found wind direction variability to be consistently higher in environments with greater
surface complexity (urban areas) and lower at higher wind speeds.

"This is important because insects are typically tracking odor plumes in
lower wind speeds, which indicates they are somehow making sense of the
high directional variability they encounter," said Houle. "Turbulence
intensity is strongly correlated with standard deviations in wind
direction, which might be useful for future wind tunnel experimental
designs aimed at recreating more 'natural' winds." Based on their
findings, Houle and van Breugel hypothesize an optimal range of wind
speed and environmental surface complexity may exist to help insects
locate an odor source.

"Further experiments will be needed to test our hypothesis and may
help us better understand the implications of land fragmentation on
the success of ecologically significant plume tracking insects, such as pollinators," said Houle. "Beyond this, our results give a compelling
reason for researchers to focus on increasing directional variability
in wind tunnel studies if they want to uncover plume tracking behaviors
that more closely resemble what we might see in nature." Next, the
researchers will apply their findings to plume tracking wind tunnel
experiments and a series of outdoor studies.

"During the summer, we plan to test our hypothesis regarding the types
of wind conditions insects might prefer while tracking odor plumes,"
said Houle. "In the lab, we're actively looking for ways to create
greater directional variability to better mimic natural wind."
* RELATED_TOPICS
o Plants_&_Animals
# Insects_(including_Butterflies) # Trees # Zoology #
Behavioral_Science
o Earth_&_Climate
# Renewable_Energy # Energy_and_the_Environment #
Environmental_Science # Weather
* RELATED_TERMS
o Monsoon o Solar_wind o Wind_power o Wind_turbine o
Ocean_surface_wave o Renewable_energy o Firestorm o Body_odor

========================================================================== Story Source: Materials provided by American_Institute_of_Physics. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Jaleesa Houle, Floris van Breugel. Near-surface wind variability
over
spatiotemporal scales relevant to plume tracking insects. Physics
of Fluids, 2023; 35 (5) DOI: 10.1063/5.0147945 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/05/230530125454.htm

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