Some insects can carry infectious diseases, posing a significant threat to human health. For instance, malaria is transmitted to people through the bites of infected female mosquitoes of the genus Anopheles, resulting in 608,000 deaths annually. The mosquitoes Aedes aegypti spread viruses that cause arboviral diseases. These insects are responsible for transmitting dengue fever, chikungunya, yellow fever, and the Zika virus. Each year, approximately 390 million people contract dengue fever, with around 20,000 fatalities.
Additionally, there are pest insects in nature that cause significant damage to agricultural crops. According to modest estimates, in 2017, the damage caused by such insects to global agriculture amounted to 162 billion USD.
Humans have long found a method to combat pests—pesticides. However, this approach has several drawbacks. Pesticides are chemical or biological substances, which means they can harm the environment or humans. Furthermore, over time, many organisms develop resistance to certain substances in pesticides, rendering these products ineffective.
Recently, another method for pest control has emerged—biocontrol of populations using genetic techniques. Among the options are:
The Sterile Insect Technique (Sterile Insect Technique), which involves releasing a large number of sterile insects (usually males) into the wild;
Gene expression control (Release of Insects carrying a Dominant Lethal). Scientists are working on creating genetically modified male insects that carry a dominant lethal gene.
However, these two methods are not entirely effective. The first requires mass production of modified males, which can be economically burdensome. As for the second method, it has been found that females, after mating with genetically modified males, continue to feed on blood and spread diseases until they die naturally, meaning this method does not fully control the population of specific insects.
Australian bioengineers Samuel Beach (Samuel Beach) and Maciej Maselko (Maciej Maselko) from Macquarie University in Sydney proposed another method to combat "bad" insects, based on genetic engineering. Unlike the two previously mentioned methods, this approach focuses directly on reducing the number of biting females immediately after mating with males.
This method involves introducing toxins from spiders and sea anemones into the reproductive organs of insects. After genetic modification, male insects begin to produce the neurotoxin themselves (genes coding for such proteins are inserted into the males' genomes) and then transfer it to females via their sperm. The toxin affects the female's body and shortens her lifespan. Thus, the males do not merely "carry" the toxin; they become constant producers of it due to the altered genes. The researchers shared their discovery in an article published in the journal Nature Communications.
The bioengineers conducted a series of laboratory experiments. Specifically, they tested seven neurotoxin proteins from various organisms on male fruit flies (Drosophila melanogaster). The toxins from the male spider Phoneutria nigriventer and the sea anemone Anemonia sulcata performed the best. Female fruit flies that mated with genetically modified males lived 37–64 percent shorter lives compared to the control group. Importantly, the modified males retained their ability to effectively attract females, which is crucial for the successful application of the method in nature.
Then, based on field trial data from other genetic pest control technologies, the scientists simulated the impact of this method on the population of Aedes aegypti mosquitoes. The simulation predicted that even a moderate level of female mortality could reduce the population by 40–60 percent faster than traditional methods.
According to Maselko, insects are unlikely to develop resistance, as the toxin targets specific genetic pathways. This means that these toxins do not pose a threat to mammals and other beneficial insects. Nevertheless, the authors of the scientific paper noted that further research on mosquitoes is necessary to conclusively confirm the method's effectiveness and safety in the wild. This could take up to three years.