Utilizing predator risk effects on mosquitoes for vector control

• Applicant: Professor Dr. Eric von Elert, Ph.D.
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543399299

There are growing concerns about the spread of mosquito-vectored diseases due to global climate change and increasing resistance of arthropods to chemical pesticides. The non-consumptive effects of fish-released infochemicals on mosquitoes during their aquatic phase are eminently underexplored with respect to vector control; this is mainly due to that the underlying infochemicals have not yet been identified. However, fish infochemicals have been shown to repel oviposition of adult and negatively affect life-history and behavior of larval mosquitoes. Each of these effects constitutes a potential mean for mosquito control and can be easily measured. Here we propose to combine a chemical with an ecological approach with the aim to identify the underlying infochemicals released by fish. This collaborative project capitalizes on the competence in identification of volatile and non-volatile freshwater infochemicals (Prof. von Elert, Univ. of Cologne, Germany) and the expertise in non-consumptive predator effects on natural mosquito populations (Dr. Silberbush, Univ. Haifa, Israel). We propose to work with five mosquito species (Culiseta longiareolata, Culex pipiens, Culex laticinctus, Culex perexiguus and Aedes albopictus (Diptera: Culicidae) of which all are known vectors of several arboviruses. Each of the effects of fish infochemicals (oviposition repellence, altered larval life history and behavior) constitutes a potential mean for mosquito control and can be easily measured. We aim at identifying the underlying infochemicals from fish and expect to find different compounds inducing either response. With respect to oviposition repellence, earlier results indicate that the fish-derived infochemical is volatile and decreased upon antibacterial treatment of the fish. We propose to investigate effects of mild antibacterial treatment of fish on repellence of mosquito oviposition using natural mosquito populations in Israel and to determine concomitant effects on the bouquet of volatiles, the latter being analyzed by gas-chromatography coupled to mass spectrometry. We will apply multivariate metabolomics analyses to identify candidate compounds and subsequently test them in field assays. With respect to fish infochemicals affecting life-history and behavior of mosquito larvae, the Von-Elert lab will use a bioassay-guided approach to establish a protocol for enrichment and purification of the kairomone from fish incubation water, and use high-resolution GC-MS or LC-MS for identification of candidate compounds. Extracts and fractions will be tested for effects on pupation and behavior in the established indoor facility in Israel making use of naturally occurring mosquito populations. This study will shed light on the role of chemical signals in mosquito ecology, and may, on the long-term, result in an application in pest control.

• DFG Programme: Research Grants
• International Connection: Israel
• International Co-Applicant: Dr. Alon Silberbush