Sensing predation: functional characterization of chemoreceptor proteins involved in predator perception in the freshwater crustacean Daphnia – an integrative approach

• Applicant: Dr. Linda Carolin Weiss
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 387756594

Sensory information often plays a pivotal role in shaping species interactions. Organisms acquire information about their biotic and abiotic environment by detecting specific chemical cues. Predation is a primary force driving adaptation. Prey species have evolved strategies to counter an increased risk of predation. Some species even only express defenses when they are needed and save costs associated with the defense, when predation risk is low and defenses are superfluous. Previously, we described the involved predator specific chemical cues, and determined the sensory organs involved in chemical cue perception. We further elucidated the neurophysiology of predator induced defences and cellular control centres. These experiments and results give a first insight into the molecular mechanisms of inducible defences. Within the obtained data, we identified the expression of an ancestral chemosensory receptor gene familie, i.e. ionotropic receptor family originating from the larger family of ionotropic glutamate receptors in Daphnia. This gene family, which has been identified in several protostomes including crustaceans has therefore been proposed, but not tested, as a novel type of chemoreceptors. In this work programme we will elaborate on this chemoreceptor gene family and the chemoreceptive mechanisms underlying predator detection. For this we will first describe the functional morphology of the Daphnia antennules and the involved centres of the central nervous system. We will further describe the transcriptome of Daphnia chemoreceptors and differential chemoreceptor expression patterns in selected tissues of control and predator exposed D. magna with a special emphasize on the ionotropic receptor gene family. To identify the receptors involved in predator perception we will use target-gene driven RNAi mediated knock down using the animals’ ability to express morphological defenses as a read-out. Overall, this project aims to understand the mechanistic underpinnings of phenotypic plasticity which is crucial for a better understanding of the evolution and maintenance of biodiversity.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Andreas Reiner