Adding Predator Cues To Biopesticides Increases Mosquito Mortality Interview with:

Lin Op De Beeck, PhD Laboratory of Aquatic Ecology, Evolution and Conservation University of Leuven Leuven, Belgium

Lin Op De Beeck

Lin Op De Beeck, PhD student
Laboratory of Aquatic Ecology, Evolution and Conservation
University of Leuven
Leuven, Belgium What is the background for this study?

Response: Mosquitoes transmit quite a few deadly diseases, including West Nile Virus. Around the world, therefore, the fight against these insects is high on the agenda. Existing strategies for mosquito control often involve the use of chemical pesticides that harm the environment. These pesticides are increasingly less effective as well, as insects can become resistant to existing products relatively quickly. Biopesticides are a possible alternative. The most commonly used biological pesticide is the Bacillus thuringiensis israelensis (Bti) bacteria. Unfortunately, mosquitoes are already developing resistance to this pesticide as well. This means we have to keep increasing the dose of Bti to kill mosquitoes, so that this biological substance, too, is beginning to harm the environment.

Therefore we set out to find a new strategy in the fight against mosquitoes. We already knew that chemical substances emitted by the backswimmer – a natural enemy of mosquito larvae in the water – trigger a stress response in mosquitoes. This stress response, in turn, suppresses the mosquito’s immune system. What makes the use of these predator cues even more interesting for mosquito control is that scientists recently found a way to produce a synthetic version of these chemical substances. We discovered that this synthetic version triggers a stress response in the mosquitoes and impairs their immune system, just like the natural predator cues. This gave us the idea to combine these synthetic predator cues with the biological pesticide Bti. are the main findings?

Response: We developed a cocktail of predator cues and a low, non-lethal dose of Bti. The predator cues trigger extra stress, so that the Bti had a strong impact despite its lower dose. As a result, the mortality rates among mosquitoes were high. As the predator cues of the backswimmer also have an impact on their targets’ immune system, the cocktail weakens the mosquitoes and larvae that it fails to kill by impairing their immune system. This could lead to adults with a shorter lifespan and can potentially result in lowered disease transmission when parasites don’t have the time to complete their incubation period inside the mosquitoes. What should readers take away from your report?

Response: The new cocktail of Bti and synthetic predator cues could be a promising new addition to present mosquito control and could make the use of Bti more efficient and more ecological. What recommendations do you have for future research as a result of this study?

Response: In future research this new cocktail should be tested in more natural conditions, also potential formulations of both products need to be evaluated. The influence of this impaired immune system on disease transmission should be studied. Thank you for your contribution to the community.


Lin Op de Beeck, Lizanne Janssens, Robby Stoks.Synthetic predator cues impair immune function and make the biological pesticideBtimore lethal for vector mosquitoes. Ecological Applications, 2016; 26 (2): 355 DOI:10.1890/15-0326

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Last Updated on August 26, 2016 by Marie Benz MD FAAD