Tiny Trackers Keep Tabs on Slugs’ Movements

31 March 2016

Scientists at one of the UK’s leading agricultural universities have implanted tiny microchips into slugs, in a bid to understand how they move around within fields and crops.

By understanding how the slugs move and behave, the researchers hope to be able to provide better advice on the use of slug control products such as AXCELA®.

“Slugs are a big problem for farmers, especially those growing crops such as cereals, potatoes and other root vegetables,” says Keith Walters, Professor of invertebrate biology and pest management at Harper Adams University, Shropshire.

“Regulations limiting what pesticides can be applied, and how they are used, are being tightened,” he says. “We hope that this study will show that the pesticide only needs to be targeted to certain areas of the field, and that this will actually be more effective.”

Prof Walters explains that earlier studies have shown how slugs congregate in patches in the field, often in areas where the soil moisture is high, or even waterlogged. But it’s not known whether the slugs stay in the same location and breed and live there, or if they are moving around the field and then stop in one of these favoured areas, before moving along again.

The researchers have implanted the microchips in 20 slugs, after anaesthetising them using carbon dioxide. Each chip, about the size of a grain of rice, carries a unique identifying number that can be read by radio signal.

PhD student Emily Forbes is the lead researcher in the study. “We will monitor the slugs’ movement at night, as that’s when they’re most active. We use a device very similar in appearance and functionality to a metal detector – when it comes within 20cm of one of the chipped slugs, it beeps and displays the unique identifier.”

By monitoring the slugs at regular intervals during the night, it will be possible to assess where and how far each has moved. The technology allows the team to ‘see’ beneath the soil, where slugs are known to move around, rather than slugs that are only on the surface.

Figures from the UK’s Agricultural and Horticultural Development Board (AHDB) suggest that slugs and snails could be responsible for more than £100m of damage to UK crops, if farmers had no chemical options available for slug control.

But Professor Walters hopes the study, which is to last three years, will allow greater understanding of slugs’ behaviour, and could indicate whether further studies on patch treatment would be viable.