Various species of beetles have engulfed grain stores and weakened food production around the world since ancient times. Today, researchers at the University of Copenhagen have discovered a better way to target and eliminate these tiny pests. Instead of using toxic pesticides that harm biodiversity, the environment, and human health, researchers seek to harness the beetles’ greatest strength against them – their precisely regulated fluid-balancing mechanism.
Up to 25 percent of the world’s food production is lost each year to insects, mainly beetles. Over the past 500 million years, beetles have successfully spread and adapted to life around the world and now represent one in five animal species on Earth. However, as early as ancient Egypt, these tough little insects invaded granaries and annoyed us humans by destroying our crops.
As a result, food production and heavy pesticide use now go hand in hand. Many of these pesticides harm biodiversity, the environment and human health. As various pesticides are phased out, new solutions are needed to target and eradicate pests without harming humans or beneficial insects like bees.
This is precisely what researchers in the Biology Department at the University of Copenhagen are working on. As part of a larger effort to develop more “green” methods of pest control in the near future, researchers have discovered which hormones regulate urine formation in the kidneys of beetles.
“Knowing which hormones regulate urine formation opens up the development of compounds similar to beetle hormones which, for example, can cause beetles to form so much urine that they die of dehydration,” says associate professor Kenneth Veland Halberg from the Department of the University of Copenhagen. Biology. He adds:
“While it may sound a bit vicious, there is nothing new in us trying to conquer the pests that destroy food production. We’re just trying to do it in a smarter, more focused way that takes more account of the surrounding environment than traditional pesticides. “
Ancient Egyptians weakened the water balance of beetles with the help of stones
The new study, along with a previous study, also conducted by Kenneth Veland Halberg, demonstrates that beetles solve the task of regulating their water and salt balance in a fundamentally different way than other insects. This difference in the biology of insects is an important detail when trying to fight certain species while leaving their neighbors alone.
“Today’s insecticides get in and paralyze the nervous system of an insect. The problem with this approach is that the nervous systems of insects are quite similar from species to species. The use of these insecticides kills bees and other beneficial insects in the field, and harms other living organisms ”. explains Kenneth Veland Halberg.
The centrality to survival of the carefully controlled water balance of beetles is no secret. In fact, the ancient Egyptians already knew how to mix pebbles in grain stores to combat these pests. The stones scratched the waxy outer layer of beetle exoskeletons, which serves to minimize evaporation of fluids.
“Regardless of whether they occasionally chip a tooth on the pebbles, the Egyptians could see that the scratches were killing some of the beetles due to the loss of fluid from damage to the waxy layer. However, they didn’t have the physiological knowledge that we have now, ”says Kenneth Veland Halberg.
One hundred billion dollars of pesticides used in the world
Pesticides have replaced pebbles. And their global use is now valued at around $ 100 billion per year. But as the rules for using pesticides become stricter, farmers are left with fewer options for controlling pests.
“The incentive to develop compounds that target and eradicate pests is huge. Food production is heavily dependent on pesticides. In Europe alone, it is estimated that food production would decline by 50 percent without the use of pesticides. With just one more targeted product on the market, there would almost immediately be huge gains for both wildlife and humans, ”says Kenneth Veland Halberg.
But the development of new compounds to fight beetles requires, among other things, that chemists design a new molecule that resembles the hormones of the beetle. At the same time, this compound must be able to penetrate beetles, either through their exoskeletons or through their diet.
“Understanding urine formation in beetles is an important step in developing more targeted and environmentally friendly pest control measures for the future. We are currently in the process of involving protein chemists who can help us design an artificial insect hormone. a lot of work to do before a new form of pest control emerges, ”concludes Associate Professor Kenneth Veland Halberg.
The study shows that beetles regulate their kidney function in a fundamentally different way than all other insects. These differences can potentially be exploited to fatally disrupt the water balance of beetles without affecting other insects.
Research data reports that this unique kidney function evolved around 240 million years ago, and the mechanism played an important role in the beetles’ extraordinary evolutionary triumph.
About one in five known animal species on Earth is a beetle. While 400,000 species have been described, it is believed that there are well over a million species of beetles in all.
The researchers used the red flour beetle (Tribolium castaneum) as a test species for the study, because it has a well-sequenced genome that allows the deployment of a wide range of genetic and molecular biology tools.
The researchers made the beetle urinate by injecting a hormone that scientists now know to regulate the formation of urine in the beetles.
Wheat weevils, confused flour beetles, Colorado potato beetles and other types of beetles and insects make their way up to 25 percent of the world’s food supply each year.
The problem is particularly evident in developing countries, where access to effective pest control is limited or non-existent.
The project was carried out in collaboration with researchers from the University of Edinburgh, Scotland and McMaster University, Canada
The study has just been published in the scientific journal PNAS.