Behavioral Responses of Daphnia Magna to Olfactory Cues.

Ecological research is vastly impacted by the decisions organisms make in response to variegated stimuli. Chemical cues have significant effects on most aquatic animals and influence behaviors consequential for their survival. Although many studies have examined olfactory responses of plankton, only a few factor in food quality and the presence of predators around. This study focuses on the behavioural response of water fleas to olfactory cues from predation, algal preference and other factors influencing food quality in an attempt to examine ecosystem functioning. These experiments were conducted with Daphnia magna who are a key species in many lentic environments, being an important primary consumer and prey for planktivorous fish. The detectability and responses of daphnia to the presented stimuli help better understand olfaction in freshwater water fleas. The fluid environment with the suspended olfactory stimuli was generated using a four-arm olfactometer. The flow of water from the corners of the olfactometer was used to create four contiguous stimulus zones that allowed the water fleas to respond to stimuli in them. The four fields were used to test 3 stimuli with a control. The types of algae used were also altered to establish preferences. This was gauged by how much they of a behaviour they triggered in the animal. The algae were grown in the lab from various cultures and examined for contamination prior to experimentation. Scenedesmus, Selenastrum and Chlorella were tested for preference. Due to the central role daphnia magna play in lake pelagic ecosystems, the knowledge obtained from this project will merit experimenters studying a variety of aquatic organisms