 |
| Male hoverfly, left, has bigger eyes than female (right). Photo Credit: Y Ogawa, Flinders University |
Scientific Frontline: Extended "At a Glance" Summary: Sexual Dimorphism in Hoverfly Vision and Flight
The Core Concept: Male hoverflies possess distinctly larger eyes and faster photoreceptors than females, providing them with advanced visual systems that support rapid, high-speed aerial pursuits for breeding and territorial dominance.
Key Distinction/Mechanism: While both sexes cruise at similar speeds when foraging for nectar, males utilize sexually dimorphic neurons to process optic flow much faster during courtship and conflict. This accelerated neural processing, combined with a smaller body size, gives males superior acceleration and agile flight responses compared to females.
Major Frameworks/Components:
- Optic Flow Processing: Sexually dimorphic velocity response neurons that detect motion and project to brain areas controlling wing beat amplitude.
- Photoreceptor Mechanics: Upgraded optical resolution and rapid photoreceptor response times directly linked to larger male eye structures.
- Biomechanical Integration: The interplay between smaller male body mass and specialized neural circuits to facilitate rapid acceleration.
- Sensorimotor Transformation: Complex neural networks that convert multisensory visual input into instantaneous motor flight responses.
Branch of Science: Neuroscience, Entomology, and Biomechanics.
Future Application: The intricate visual-motor skills and network-level brain systems of hoverflies serve as biological blueprints that can be reverse-engineered to improve drone maneuverability, artificial machine vision, and advanced human flight technologies.
Why It Matters: Hoverflies are the second most important pollinators of plants and flowers globally, just behind bees. Understanding the intricate neural mechanisms driving their navigation not only deepens our knowledge of their ecological survival but also drives transformative innovation in aerospace engineering and robotics.
Female behavioral response to sideslip optic flow. The video on the left shows a tethered female hoverfly filmed from above, with colored dots indicating the body parts tracked by DeepLabCut to extract wingbeat amplitude (WBA, black-red), head angle (yellow-green), and foreleg (blue-cyan) and hind leg (magenta-green) kinematics. The stimulus viewed by the hoverfly is shown on the right, with stimulus velocity indicated above the hoverfly video. Note how the different body parts move in coordination.
Many male hoverflies have larger eyes than females, giving them the advantage of better optics and faster photoreceptors in high-speed pursuits to find preferred partners for breeding.
New research led by Flinders University—aimed at understanding the deft flying skills of these fast and dexterous native flies—compared different flight speeds between the sexes as key attributes for their survival success.
The study reveals a complex interplay between the key functions of both sexes and their regular cruising speeds.
This reflects the biomechanical qualities, multisensory integration, and circuit-level differences in their Top Gun–style high-speed pursuits.
"We know males fly much faster than females during courtship and territorial encounters, but that males fly as slowly as females when looking for flowers to feed from," says Karin Nordström, professor of neuroscience and co-senior author of the article published in the journal eLife.
"We found that the velocity response functions of the neurons that detect optic flow were sexually dimorphic," says Nordström, professor of neuroscience at the Flinders Health and Medical Research Institute (FHMRI).
"As the neurons project to the areas that control wingbeat amplitude, we next recorded their response in tethered flight."
By contrast, researchers found no difference in wingbeat amplitude in response to similar stimuli when the hoverflies were tethered.
Hoverflies are the second most important pollinators of plants and flowers after bees. Their ability to navigate in the natural world, including finding suitable flowers to feed from, depends on their visual systems.
Sarah Nicholson, research associate in the Neuroscience of Insect Vision Laboratory, says the differences between male and female optic-flow-sensitive neurons match the males' larger eyes.
"At the same time, the smaller body size of male hoverflies compared to females gives them an advantage for faster acceleration and more agile flight responses," she explains.
Senior co-author Dr. Yuri Ogawa, also part of the Hoverfly Vision neuroscience research group at the College of Medicine and Public Health, says, "We are learning a lot about how these complex visual-motor skills, rapid photoreceptor systems, and network-level brain systems work, both on a neural and behavioral level."
"In turn, science, engineering, and human flight can benefit from new insights into how these visual systems create such exquisite flight behaviors," says Dr. Ogawa.
Published in journal: eLife
Title: Sexual dimorphism in sensorimotor transformation of optic flow
Authors: Sarah Nicholas, Katja Sporar Klinge, Luke Turnbull, Annabel Moran, Aika Young, Yuri Ogawa, and Karin Nordström
Source/Credit: Flinders University
Reference Number: ns051726_01
.jpg)