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Flying insects possess sophisticated olfactory systems that they use to find food, locate mates, and avoid predators. It is suspected that insects flap their wings to draw odor plumes toward their antennae. This behavior enhances their olfactory sensitivity and is analogous to sniffing in mammals. However, insects’ wing kinematics change drastically as their flight speed increases, and it is unknown how these changes affect the insect’s odorant perception. To address this question, we simulated odor-tracking hawkmoth fight at 2 m/s and 4 m/s using an in-house immersed-boundary-method-based CFD solver. The solver was used to solve the Navier-Stokes equations that govern the flow, as well as the advection-diffusion equation that governs the odor transport process. Results show that hawkmoths use their wings to significantly increase the odor intensity along their antennae. However, peak odor intensity is 39% higher during 2 m/s flight than 4 m/s flight. We therefore suspect that insects have greater olfactory performance at lower forward flight speed. Findings from this study could provide inspiration for bio-inspired odor-guided navigation technology.
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This content will become publicly available on February 1, 2026
Benefits of low-speed flight in odor-tracking navigation for hawkmoths
Flying insects are equipped with complex olfactory systems, which they utilize to seek food, identify mates, and evade predators. It is suspected that insects flap their wings to draw odor plumes toward their antennae, a behavior akin to mammals' sniffing, aimed at enhancing olfactory sensitivity. However, insects' wing kinematics change drastically as their flight speed increases, and it is unknown how these changes affect the insect's odorant perception. Addressing this gap in knowledge is crucial to a full understanding of the interplay between insects' aerodynamic performance and sensory perception. To this end, we simulated odor-tracking hawkmoth flight at 2 and 4 m/s using an in-house computational fluid dynamics solver. This solver incorporated both the Navier–Stokes equations that govern the flow, as well as the advection-diffusion equation that governs the odor transport process. Findings indicate that hawkmoths enhance odor intensity along their antennae using their wings, with peak odor intensity being 39% higher during 2 m/s flight compared to 4 m/s flight. This demonstrates there is a trade-off between rapid transport and olfaction, which is attributable to differences in wing kinematics between low- and high-speed flights. Despite literature suggesting hawkmoths are limited to steady forward flights at speeds below 5 m/s—about half of what is theoretically predicted based on body mass—this study reveals that slower flight speeds improve their olfactory capabilities during navigation. Our findings offer insights into the evolution of flight and sensory capabilities in hawkmoths, as well as provide inspiration for the development of bio-inspired odor-guided navigation technologies.
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- Award ID(s):
- 2453175
- PAR ID:
- 10613200
- Publisher / Repository:
- AIP Publishing
- Date Published:
- Journal Name:
- Physics of Fluids
- Volume:
- 37
- Issue:
- 2
- ISSN:
- 1070-6631
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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