An effective method for luring lady beetles in the laboratory

The second step was the formulation of these molecules for using them in crop fields, and this was the actual goal of the research. Once analysed from every angle, it was possible to reconstitute the blend of molecules. Or nearly, because the fifth molecule, α-bulnesene, isn’t commercialised. Luckily, it was only present in small quantities and its absence in the formulation had no effect on the attractiveness of the synthetic pheromonal blend. The reconstitution was a success. The blend created in the laboratory attracted the males as much as the blend produced by a live lady beetle. They headed for the source, convinced that they would find a partner ready to mate.

From the lab to the fields

Now, the researchers have to find a practical application for this discovery. The idea is to concentrate the lady beetles that are close to a field area where we want them to go. Simulating the presence of females in the fields should attract the males and increase the lady beetle populations in the desired place.

But to achieve this goal, it is necessary to find a suitable tool which will ensure a controlled distribution of these odours from a precise source. "We are optimising the incorporation of these odours in dispensers, which could be placed in areas infested with aphids", the entomologists explain. "We have several possibilities to find the ideal formulation. In the spring, we will test the effect of our blend outside the walls of the laboratory and observe what happens. Initially, we will work on a small scale, in greenhouses, which will allow us to control a maximum number of parameters. The outside climatic conditions are more random. For instance, the wind and humidity are factors we can’t control, and they will probably influence our results."

But, of course, the final destination is out in the open air. Thanks to the AgricultureIsLife platform, Bérénice Fassotte has two fields to test the diffusion of the synthetic pheromonal blend. Currently, the researchers don’t know how the males will react once they will realise they’ve been tricked. Even if their behaviour in the laboratory was encouraging. The first parameter to monitor will be the presense, or not, of a greater number of males in the targeted areas; the second will be the hypothetical reduction of aphids. Once out in the open, will the males wait to get some energy back, or will they fly off? One thing’s for sure, they won’t get what they were looking for. The fact that this new agricultural protection system doesn’t allow an invasive species to proliferate is a good thing. And as a consolation prize, the males will have a choice meal before leaving and search for real females, if they’re lucky.