Parasites play crucial roles in ecological, economic, and evolutionary contexts. Understanding the mechanisms behind successful infection is of great interest to biologists, epidemiologists, and agricultural scientists alike. Many parasites, especially those with complex life-cycles (i.e. involving several hosts), adopt a common strategy of manipulating host behavior to enhance transmission. The molecular mechanisms responsible for host manipulation remain poorly understood, leading to a significant knowledge gap in understanding parasite evolution, distribution, and their broader impact on ecosystems. The goal of this project was to shed light on the mechanisms underlying behavioral manipulation on the example of nematomorph parasitoids. Adult nematomorphs exhibit the remarkable ability to compel their final insect hosts to seek out water and drown themselves, facilitating the nematomorphs’ transition into freshwater habitats. Host-parasite interactions require a high degree of biochemical co-evolution and communication, which is why we decided to investigate the role of neuropeptides in nematomorph host manipulation. The three main aims of the project were:
1) Analyze the neuropeptide complement of parasite and host
2) Determine the binding affinity of host receptors to parasites neuropeptides
3) Study the effects of the peptide-receptor interactions on host behavior
By studying how nematomorphs interact with the host, we can identify genetic and physiological adaptations that have allowed them to survive as parasites and gain insight into how they interact with their hosts. The results could not only contribute to our understanding of host manipulation by nematomorphs but will also establish a basis for studying other parasites and animal cross-species interactions, including those with significant medical and agricultural implications.