By the sun and the wind: Wits and Lund universities make major discovery about dung beetles

Dung beetles point way for machine learning

29 October 2019 - 09:58
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Dung beetles have a fall-back system of compass cues that they can switch between.
Dung beetles have a fall-back system of compass cues that they can switch between.
Image: Supplied/Wits University

Have you ever wondered why dung beetles don’t get lost, even when they navigate vast expanses backwards?

A research team led by Marie Dacke, professor of sensory biology at Lund University in Sweden, and renowned biology researcher Prof Marcus Byrne from the University of the Witwatersrand (Wits) has answered this question.

The discovery that dung beetles use different directional sensors — a so-called “wind compass” and “sun compass” — to achieve the highest possible navigational precision in different conditions has broken new ground for artificial intelligence (AI), robotics and machine learning.

Path for machine learning

Dung beetles have a fallback system of compass cues that they can switch between, depending on which one is providing the most reliable information for orientation, says Byrne, who has collaborated with Dacke for almost 20 years on dung-beetle orientation.

“This is the first study that shows how an animal’s biological compass can integrate different directional sensors — in this case the wind and the sun — in a flexible way. This enables the highest possible precision at all times,” says Dacke.

When it's cloudy or when the sun is higher than 75° above the horizon at midday, dung beetles cannot use the sun as a directional guide, so they focus on the wind. A couple of hours later, when the sun is a little lower, they turn off their wind compass and again rely on the sun to navigate.

The aim of the research is to understand how tiny brains handle large amounts of information to make a relevant decision: is it appropriate to turn left or right, or to continue straight on?

Byrne says: “Choosing the most important job at any given moment is a task most computers struggle with, which we all know about from the frustration of attempting to send an e-mail while our machine checks its virus protection.” 

Dacke believes the results will be of direct benefit within a few years in areas such as robot development and artificial intelligence. Just like dung beetles, robots must take large amounts of information into consideration to direct their next action.

Understanding navigational orientation

The researchers investigated dung beetles in the field and in the laboratory. Using fans to create and manipulate wind direction, they examined how it affects the insects' directional awareness. This was also done with the sun by artificially changing its position with a mirror.

The results show that directional information can be transferred from the wind compass to the sun compass and vice versa. In this way, the dung beetles can track their course when one of the compasses becomes less reliable.

“The insects' brains are definitely not preprogrammed to always follow the same set of actions. We can show that such small brains work according to dynamic principles that adapt to the conditions prevailing at a given moment,” says Dacke.

The researchers had previously shown that, during the night, some dung beetles orientate by the Milky Way and polarised moonlight while rolling their dung balls in a straight line.

Combining the results of their study with the results from the Milky Way study, they showed that the insects' compass worked at all times of the day or night — and probably under almost any conditions.

Leading machine learning

Wits is pushing far into the future in many ways through its postgraduate programmes in machine learning, AI and robotics.

The Wits School of Chemistry recently launched a new AI research initiative for Africa. Hosted by the Molecular Sciences Institute (MSI) in the School of Chemistry, the newly formed Cirrus Initiative will focus on the analysis of research data in chemistry using machine learning while collaborating with physics, technology and engineering projects.

Cirrus aims to create a collaborative university and industry platform supporting an African ecosystem that fosters innovation and entrepreneurship. As the host university, Wits will lead the initiative's co-operation efforts with universities, institutes, centres of excellence and research groups across Africa.

Join one of the leading teams of researchers at Wits University and advance to the top in modern science and technology. A postgraduate degree in these fields, which have huge demand and a skills shortage, will let you pioneer the use of new technology to make advances in all areas of society.

For more information about the world-changing future work you can conduct at Wits, click here.

This article was paid for by the University of the Witwatersrand.

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