Meeting Abstract
Sticklebacks infected by the parasitic flatworm Schistocephalus solidus show large changes in phenotype, including a lack of the typical behavioural response to predator presence. Interestingly, these changes occur when the parasite is ready to move to its final host (a piscivorous bird) to reproduce, which makes it an ideal model for studying the mechanisms of behavioural modification by parasites. However, whether this drastic behavior change is a by-product of facing a parasitic infection, or the result of a direct manipulation by the parasite is unknown. We used two approaches to test predictions arising from these hypotheses. First, we used phenotypic engineering to recreate the behavioural modifications using pharmacological manipulations. We were able to recreate some aspects of the behavioural modifications observed in a parasitized fish, but not others. Second, we used an RNA-Seq analysis to compare the whole-brain transcriptome of healthy, exposed, infected and pharmacologically manipulated (fluoxetine) sticklebacks, to define a genomic signature of Schistocephalus infection in the host brain, and to uncover overlaps in transcriptomes between infected and fluoxetine-treated fish. Our use of a combined approach to uncover the causes of behaviour modification by a parasite will contribute to shed a new light on this parasite-host interaction.
