Our planet is plagued with numerous problems; some are old, some are new, and many are manmade. One problem we are facing is that of Invasive Alien Species (IAS). These are plants, animals, and organisms that find their way into ecosystems they are not native to. Sometimes they are introduced by accident and sometimes they are introduced on purpose, for example as a pest control method.
The issue that can arise is that—as the name suggests—they become invasive and a pest themselves. They can negatively impact the new ecosystem by attacking native species or outcompeting for food sources. As a result, native species encounter the danger of extinction or have to move elsewhere because their habitat has become so altered that it is no longer livable for them. In short, IAS have a detrimental effect on biodiversity.
Interested to hear more about IAS? Watch this video.
One IAS that was introduced on purpose in places around the world is the mosquitofish. As the name suggests, the little fish was thought to help in decreasing mosquito populations by preying on its eggs. It was introduced in the early 20th century to fresh waterways as a way to limit the spread of malaria-carrying mosquitos.
Yet, how did the little fish, which was supposed to help, land on the 100 world’s worst invasive species list by the International Union for Conservation of Nature (IUCN)? Well, it turned out that the mosquitofish was no better at fighting off mosquitos than the mosquito’s natural predators. Alternatively, the mosquitofish was good at colonizing the new ecosystem, outcompeting other native species for food, and attacking and damaging the tails of other fish and tadpoles. Mosquitofish are highly predatory and eat the eggs of economically desirable fish, which impacted the fishing industry. It also pushed many rare and indigenous species to becoming endangered, in countries such as Australia and Spain.
The optimal way to deal with IAS is to prevent them from occurring in the first place, because once they become established in a given ecosystem, they are extremely difficult and expensive to remove. One of the reasons the mosquitofish became an IAS is that the new ecosystems lacked a natural predator to keep their numbers in check. However, as innovative technologies are developed, researchers are finding novel ways to deal with the problem.
An international team of researchers from the University of Western Australia (UWA), University of Padova, and New York University, led by Dr. Giovanni Polverino, have been developing a robotic predator that can curb the spread of mosquitofish. They created a robot-fish in the likeness of the natural predator of the mosquitofish, the largemouth bass, and designed it to exhibit the predatory mannerisms that would scare off mosquitofish.
The robot is equipped with an algorithm to attack mosquitofish if they approach tadpoles, making them flee in fear. In this way, the endangered tadpoles can develop in safety without being harassed by the predatory behavior of mosquitofish. Dr. Polverino and his team realized the opportunity that this provided and designed the robot-fish to affect the mosquitofish behavior.
By introducing this robotic predator, the mosquitofish became more preoccupied with survival and exhibited more anxious responses; their health deteriorated and their fertility decreased. What is interesting is that those effects lasted weeks after the robot-fish was removed from the tank where the experiments took place. Instinctively, the mosquitofish flight or fight response is programmed to respond to their natural predator, even though they lived in ecosystems where they have never encountered them. The robot-fish was able to switch on these instinctive fear responses.
In an interview, Dr. Polverino said: “Our approach also has a non-lethal effect. We are stressing them in a very natural way by replicating predator-prey dynamics. . . We developed a robotic tool, but we also established a piece of knowledge: by injecting fear, you can cause a long list of collateral effects on the long term.”
While the research team discovered an effective way to control, and maybe eradicate, the mosquitofish population, they are still working on how to translate their findings and solution from the lab into the real world. Hopefully, this work comes to fruition; if it does, it would be a great asset to have in the fight against invasive species, and different models can be developed for various IAS.
Interested to find out about other ways IAS were dealt with? Check out this video.
References
azorobotics.com
cell.com
uwa.edu.au
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