Researcher uses tiny trackers to learn about slug behaviour

Posted 14 March 2016

Researchers at Harper Adams University are tracking slugs to learn more about how they move within the field in order to improve control of these crop pests.

Keith Walters, Professor of invertebrate biology and pest management, said: “Slugs can be a big problem for farmers especially for those growing crops such as cereals, potatoes and other root vegetables.

“By understanding how the slugs move and behave, we will be able to advise farmers on how is best to use their pesticides.

“This is becoming increasingly important because regulations limiting what pesticides can be applied and the way they are used are being tightened due to environmental concerns.

"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.

“From previous studies, we can see that slugs congregate in patches in the field. These patches normally form in areas where the soil moisture is high, or even waterlogged. 

“What we don’t know, is if the slugs stay in the same location and breed and live there, or if they are moving around the field and then stop for a while at one of these ‘slug utopias’ before moving along again.”

PhD student Emily Forbes is the lead researcher in this study. She said: “We will be conducting our research at night, as that’s when the slugs are most active. 

“We will be releasing tagged slugs into the field and then monitor their movements by returning to them at intervals throughout the night.”

Lecturer in entomology Dr Tom Pope said: “We are tracking the slugs by using a small device, which is about the same size as a grain of rice.

“This is inserted into an anaesthetised slug. We are carefully studying the slugs to ensure that inserting the tracking device does not harm or otherwise affect the behaviour of the slugs.

“We can monitor the slugs by using a detector, not too dissimilar from a metal detector. When the detector comes within about 20 cm of the tagged slug, it beeps and displays the slug’s tracking number on the screen. We are then able to note down the slug’s location and see how far it has moved since it was last detected.

“This technology has been used in a previous project at the university, but it is the first time it has been used on slugs in this way.

“We are planning to track large numbers of slugs so that we gain a much better picture of their movements.”

Emily said: “With this technology we can see what is underneath the soil, as many studies have only looked at the slugs on the soil surface. With the research we have done so far, we have seen that some of the slugs do go into the ground and cannot be seen. Therefore, these slugs would not have always been counted in previous studies.”