Ladder-walking locusts show big brains aren't always best

December 24, 2009

Scientists have shown for the first time that insects, like mammals, use vision rather than touch to find footholds. They made the discovery thanks to high-speed video cameras - technology the BBC uses to capture its stunning wildlife footage - that they used to film desert locusts stepping along the rungs of a miniature ladder.

The study sheds new light on insects' ability to perform complex tasks, such as visually-guided limb control, usually associated with mammals.

According to lead author Dr Jeremy Niven of the University of Cambridge: "This is another example of insects performing a behaviour we previously thought was restricted to relatively big-brained animals with sophisticated motor control such as humans, monkeys or octopuses."

Because insects such as bees and flies spend a lot of time flying, most research has concentrated on how insects use vision during flight. Many insects that spend a lot of time walking, such as stick insects, crickets and cockroaches have relatively small eyes and use long antennae to 'feel' their way through the environment.

Locusts spend time both walking and flying, and have short antennae and large eyes, which made Niven wonder whether they used vision to find footholds.

To answer this question, the team built a miniature locust-sized ladder and filmed the locusts walking along it. They counted the number of times the locusts missed steps, comparing the number of mistakes they made in different situations.

"By combining all these different experiments, we showed that locusts use vision to place their legs. We showed that when locusts can't see one front leg they stop using that leg to reach to the next ladder rung, favouring the leg they can see," Niven explains.

"Big-brained mammals have more neurons in their visual systems than a locust has in its entire nervous system, so our results show that small brains can perform complex tasks. Insects show us how different animals have evolved totally different strategies for doing similar tasks," he says.

As well as illustrating how insects can achieve similar results to mammals by using simpler mechanisms, the findings deepen our understanding of locusts' neural circuits.

This is important because locusts have been a model organism for studying limb control for the past 40 years. Insects such as the locust have been crucial to many breakthroughs in neuroscience, and insects are often the inspiration for limb control in robotics.
-end-
The results are published today in Current Biology.

For additional information and locust ladder-walking video clips, please contact:
Becky Allen, Office of Communications, University of Cambridge
Tel: +44 (0)1223 332300, mobile: +44 (0)7500 883644, email: becky.allen@admin.cam.ac.uk

Notes to editors:
The paper, Jeremy E. Niven et al, 'Visual targeting of forelimbs in ladder-walking locutsts' is published in Current Biology on 24 December 2009.

University of Cambridge

Related Walking Articles from Brightsurf:

Why walking to work may be better for you than a casual stroll
Walking with a purpose -- especially walking to get to work -- makes people walk faster and consider themselves to be healthier, a new study has found.

Spinal cord gives bio-bots walking rhythm
Miniature biological robots are making greater strides than ever, thanks to the spinal cord directing their steps.

These feet were made for walking
Many of us take our feet for granted, but they have a challenging job in the biomechanics department.

Walking sharks discovered in the tropics
Four new species of tropical sharks that use their fins to walk are causing a stir in waters off northern Australia and New Guinea.

Micro implants could restore standing and walking
Researchers at the University of Alberta are focused on restoring lower-body function after severe spinal injuries using a tiny spinal implant.

Walking changes vision
When people walk around, they process visual information differently than at rest: the peripheral visual field shows enhanced processing.

Virtual walking system for re-experiencing the journey of another person
Virtual-reality researchers have developed a virtual-walking system that records a person's walking and re-plays it with vision and foot vibrations.

A large study indicates how cities can promote walking for travel
Coinciding with the European Mobility Week, a study performed in seven European cities focuses on walking for travel, a strategy to increase physical activity in cities.

Robotic cane shown to improve stability in walking
By adding electronics and computation technology to a simple cane that has been around since ancient times, Columbia Engineering researchers have transformed it into a 21st century robotic device that can provide light-touch assistance in walking to the aged and others with impaired mobility.

Water walking -- The new mode of rock skipping
Utah State University's Splash Lab not only reveals the physics of how elastic spheres interact with water, but it also lays the foundation for the future design of water-walking drones.

Read More: Walking News and Walking Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.