A bizarre, but poison-free control option is emerging: researchers have uncovered special features of kidney function in beetles that open up potential for the development of targeted insecticides. Beetle-specific messenger substances could therefore force the crawlers to pass excessive urine, so that dehydration ultimately kills them. This approach could avoid “collateral damage” caused by the pesticides used to date.
Pesticides have a bad reputation because they are known to damage biodiversity and threaten animal and human health. Unfortunately, they are often necessary: Without the use of measures or substances that keep pathogens, weeds and pests in check, it would not be possible to feed the world’s population. There are also quality standards: Consumers prefer flawless agricultural products in the supermarket. Insect pests are particularly important when it comes to food losses and deterioration in quality. The most important role is played by representatives of the beetles, which eat plants or hunt for supplies in granaries and the like. If they are not controlled by pesticides, there is a risk of total failures.
More ecological pesticides are in demand
But the previous control agents are problematic: “The common insecticides mostly act on the nervous system of the insects. The problem with this approach is that the nervous systems of all insect species are quite similar, ”explains Kenneth Halberg of the University of Copenhagen. As a result, they not only affect the “bad guys”, but also threaten organisms that are not in focus. “The use of these insecticides can damage bees and other useful field insects as well as many different living things,” says Halberg. There is therefore a threat of complex adverse effects on biodiversity, the environment and human health. This is why there is a great need for pesticides that specifically only have an effect on beetles.
To do this, one would therefore have to identify a starting point that is unique to these insects. This is exactly what Halberg and his colleagues succeeded in doing. As part of their study, they looked at kidney function and thus with the beetle’s water balance system. They carried out their investigations on the red-brown rice flour beetle (Tribolium castaneum) as a model. Extensive genetic information is already available about this stored pest and many techniques are available for studying its physiology.
As the scientists explain, when they reach a certain level, beetles also have to excrete toxins and wastes from their bodies through the release of fluids. However, fine coordination with the water balance is necessary so that critical dehydration does not occur due to losses. By using various molecular biological methods, the scientists have now been able to show that beetles regulate their kidney function fundamentally differently than all other insects. A hormonal system is responsible for controlling urine production, which was specifically created in the beetle’s line of development. The researchers were also able to clarify the significance of the messenger substances they identified through experiments: They induced their test beetles to urinate in a targeted manner by injecting them with a substance that had a corresponding hormonal effect.
Urine drivers instead of nerve poison
It is precisely in this effect that the potential for the development of new pesticides could lie, the scientists say: “Knowing which messenger substances regulate urine production in beetles opens up the possibility of developing compounds that are similar to hormones, and thus effect them that the beetles produce so much urine that they die of dehydration, ”explains Halberg. In plain language this means: You could make the beetles pee to death. “That may seem particularly malicious, but it is nothing new that we are trying to defeat pests with ruthless methods,” says Halberg. “We are now planning to do it in a smarter, more targeted way than is possible with traditional pesticides.”
The scientists emphasize that there are still a few hurdles to overcome before a “pee agent” can put an end to problematic beetles. The development of appropriate active ingredients therefore requires, among other things, that chemists develop a molecule that resembles the beetle hormones and can be produced on a large scale. In addition, this compound must be converted into special formulations so that they can get into the beetles – either through absorption via the body surface or through ingestion. “We are now in the process of bringing in protein chemistry specialists who can help us develop an artificial insect hormone. But there is still a long way to go before this new form of pest control can see the light of day, ”says Halberg.
In conclusion, he once again emphasizes the great need for alternatives to the previous pesticides used against beetles: “Food production is highly dependent on pesticides. It is estimated that in Europe alone food production would decline by 50 percent without control measures ”. The commitment is therefore correspondingly large. “If only one single, more targeted product were available on the market, immense benefits for both the animal world and humans would arise immediately,” says Halberg.
Source: University of Copenhagen, Article: PNAS, doi: 10.1073 / pnas.2023314118