EFAsense

How animals perceive their environment also depends on what they eat. Specific omega-3 fatty acids from algae, such as DHA and EPA, make nerve cell membranes more flexible and support signal transmission. If they are lacking, sensory cues may be harder to detect, signals may travel less efficiently, and learning can suffer. At the same time, warming and nutrient inputs are changing algal communities in many lakes and can reduce the natural supply of these fats. This project asks how food quality shapes perception and behaviour in water fleas (Daphnia). In the laboratory, Daphnia receive diets that differ in the amount and composition of omega-3 and omega-6 fatty acids. We track which fats reach their neurons, test how easily nerve responses are triggered, and observe behaviour in light and in the presence of fish warning cues. We also compare populations from lakes along a nutrient gradient with contrasting natural omega-3 availability. Further experiments test whether the effects of omega-3 deficiency can be reversed by improving diet. By linking diet, nervous system and behaviour, we aim to clarify basic mechanisms in a keystone grazer. Changes in Daphnia behaviour can cascade through entire food webs, because they are a key stone species linking the basis of the aquatic food web to fish and eventually also humans. So our findings can inform freshwater management. Because the underlying biology is shared across many animal groups, the work may also inspire guidance on adequate omega-3 intake.