Researchers from the National University of Quilmes have developed and patented a kit for the sequential biological control of leaf-cutting ants. This consists of the gradual application of baits that the insects do not recognize as something harmful and, therefore, transport them to the nest. The kit is made up of three formulas and each contains at least two agents: one that attacks the animals and another that attacks the fungus they feed on. If the amount of food is reduced, the queen of the colony is more likely to starve. Thus, scientists fight the problem on two different fronts.
“Since ants are also very numerous, they range from hundreds of thousands to millions per anthill and biological controllers have a certain time of action to grow, develop and kill the ant. Control is not quick as with chemical insecticides,” she says. Patricia Folgaraitprofessor at the University and main researcher at Conicet, in dialogue with the UNQ Science News Agency. Therefore, as successive applications are needed to control them, a product is needed that deceives them and they cannot associate it with something harmful.
Leaf-cutter ants are the main herbivores in and around the tropical Americas, and their impact on agriculture is estimated to be in the billions of dollars each year. By building their well-protected nest underground, it is difficult to directly apply poisons or pesticides that could result in effective control of the entire colony.
Biological control, as opposed to chemical control, is much more specific for these insects. “It is not necessary to kill all the ants because they are very beneficial for the ecosystem.we must try to lower the populations below the level of economic damage of those that are just pests”, explains the scientist.
kickoff
Although biological control is a very old technique (much older than chemical insecticides), researchers point out that nobody dared to use it with social insects like ants because they have a very advanced social structure and, with overlapping generations -grandparents can live with children and grandchildren-, knowledge is transmitted and this increases the difficulty of control. Furthermore, as it has a caste society where each insect has a specific function, the day-to-day life of an anthill is very efficient.
On the other hand, and particularly with leaf-cutting ants, they have social immunology: Not only do they defend against disease at the individual level, but there are behaviors at the colony level that together can reduce the onslaught of pathogens..
“I believe that no one has dared to do biological control with social insects because they are incredibly difficult. When you kill a lobster, you kill the female that no longer reproduces and doesn’t produce offspring that could cause harm. On the other hand, in the colony you can kill 100,000 ants that are all workers and all female, but none reproduce. If you don’t kill the queen, which is the only one that reproduces in the colony, it doesn’t matter”, points out Folgarait, PhD in Biology.
Ants and their benefits
Contrary to popular belief, ants are in an environment for a reason and they offer many benefits other than the fact that they are pests. As long as it is possible to maintain a certain level of ant nests in a given area, the balance for the ecosystem is positive..
“First of all, ants are part of the primary decomposers of the ecosystems in which they are found. They are also very important in soil removal and aeration to generate fertile land: where there are usually anthills, there is a lot of plant growth in the areas”, tells the Scientific News Agency Daniela GoffreUNQ and Conicet researcher who is part of the work.
These insects have a positive impact on vegetation, as they create the necessary conditions for plants to carry out photosynthesis and generate their own food.. In fact, in certain places in Venezuela, the installation of some bushes depends on the existence of anthills.
“With several ants we have already shown that the concentration of nutrients in anthill soils is much higher because they take nutrients from below and store them in their nests, which are often above the ground, which also brings a series of benefits if the producer knows how to take advantage of it”, highlights Folgarait.
Argentine pride
Ants, like many other insects, arrive by human transport to different countries and continents where they are not native.. When they arrive, they do so alone, without their competitors, their parasites, their pathogens and everything that keeps them under control in their place of origin. If the queen is fertilized and has characteristics that allow it to become a pest, they settle there and begin to displace the natives from the new location.
Currently, there are two species in particular that are very harmful. One is thefire ant”, also known as the red ant, in charge of making mounds in the garden and causing severe pain if it injects its stinger into a person. This insect invaded the United States about 100 years ago and is still a problem today. Furthermore, it is found in other places like Australia, China, and Japan. The other species is known as “Argentine ant”, which also began its invasion in the United States and is currently found in Australia and New Zealand, among other places. In fact, in Europe there is a colony of this species that occupies six thousand kilometers.
“Around people know them as urban ants that we find in our homes, in gardens and, in general, they do not cause us any problems. For us it is not a very important pest, unless we have it in large numbers in places where they can be transmitting diseases”, he describes to Scientific News Agency Conicet’s principal investigator.
True love
In addition to their duties and responsibilities, Patricia Folgarait defines herself as “a lover and admirer of ants“. Being also an ecologist, her concern for the environment led her to work only with biological products and not to use chemical compounds.
Their goal is not to extinguish or exterminate ants, but to reduce populations so they don’t cause problems for people.. “This is a very different approach to typical agronomists, who just want to totally eradicate a pest and don’t worry too much about how to do it. That’s not part of my philosophy,” he says.