Mapping beetles’ wiggle could help battle global food security

Researchers from the University of St Andrews have uncovered the surprising mechanics behind the wriggle of the red flour beetle, findings which could help combat infestation and threats to food security.

It’s estimated that 20% of the developing world’s stockpiles of flour and grain are infested and spoiled each year by red flour beetles and pests like them, along with 9% of stocks in the rest of the world. However, until now it wasn’t known how or why these beetles were so effective at burrowing.

The new findings could change the way pest infestations are tackled in the future and inspire new ideas in robotics.

The study, published today in the Journal of Experimental Biology, was spearheaded by a fourth-year undergraduate Bella Xu Ying, working with Drs. Maarten Zwart and Stefan Pulver in the School of Psychology and Neuroscience.

The team discovered that red flour beetle (Tribolium castaneum) larvae perform best on rough, fibrous surfaces like paper and cardboard. On these substrates, the larvae use a wave-like walking pattern that starts at the back and moves forward, providing both efficiency and flexibility.

When the larvae encounter more demanding conditions, such as steep slopes or the need to tunnel into flour, a key food source, they switch tactics by deploying tiny structures called pygopods at the rear of their bodies to grip and stabilize themselves.

Further experiments showed that disrupting the neural connections between the larvae’s front and back body sections severely hampers their ability to climb and tunnel. This finding highlights the critical role of posterior abdominal structures in adapting their movements to environmental challenges and shows that they need their tail to infest food stores.

First author Bella Xu Ying said, “It’s not often you’re given a blank slate and told ‘no one knows how this thing moves, go and find out!’. This gave us a lot of freedom in the questions we could ask, to both fulfill our curiosities as motor systems neuroscientists but also uncover foundational results that could inform new practices in sustainable agriculture.

“In the future, we would love to find out what types of neurons and molecules connect their brains, legs and pygopods, to help develop more specific methods that inhibit their infestation without damaging the crops themselves.”

Dr. Zwart said, “It has been exciting to delve into the world of red flour beetle larvae and uncover the elegant ways they adapt their movements to tough, ever-changing environments. Our work not only reveals a remarkable neural and biomechanical strategy but also hints at exciting new approaches to enhance food security and design agile bio-inspired robots.”

Dr. Pulver said, “This is a great example of how student-led interdisciplinary research at St Andrews can generate insights and impacts that reach beyond Scotland.”

This work shows that even small insects have sophisticated motor strategies to overcome challenging environments. With stored grain losses due to pests like the red flour beetle estimated at around a fifth worldwide, understanding these locomotor strategies offers exciting potential for development in many fields.