Mosquitoes looking to mate in Australia are about to have the worst sex of their lives – thanks to genetic modifications turning their semen toxic. That's part of a new mosquito population control method set to be trialed by Macquarie University researchers looking to curb the spread of diseases carried by these insects. Talk about drastic measures, huh?
It's called the 'Toxic Male Technique (TMT),' and it involves engineering male mosquitoes to produce venom proteins in their semen with the goal of killing their female counterparts – which do all the biting and feeding on blood – soon after mating.
It can negate the need for insecticide sprays, and target these harmful disease-spreading species specifically. The researchers are looking squarely at a couple of species that spread malaria, dengue, Zika, chikungunya disease, and yellow fever.
There have been other attempts to check the growth of mosquito populations, including Sterile Insect Technique and insects carrying lethal genes (RIDL). These involve releasing sterilized or genetically modified males to mate with females, resulting in no offspring being produced, or producing offspring that die soon after birth.
The trouble with both of these methods is that they don't impact the current generation of mosquitoes that can continue to bite people and spread disease. For reference, female mosquitoes can live and feed on blood for several weeks.
This is where TMT can be more effective: it targets the current generation of harmful female mosquitoes and prevents them from biting people as soon as they mate.
TMT is targeted precisely, so other beneficial species aren't affected – not even those that feed on these mosquitoes. This method is also worth exploring because of the rising resistance to pesticides in mosquitoes, which can also spread to different places and make it hard to curb their ability to spread disease around the world.
Sam Beach, lead author of the paper published in Nature, told The Guardian this method could greatly impact the spread of disease if the team's plan works. “With this approach, we can immediately reduce the size of the female mosquito population and then hopefully get a really rapid reduction in the spread of these vector-borne illnesses,” he said.
So where are we at now? The research team hasn't yet tried this on mosquitoes. However, TMT tests on fruit flies demonstrated female flies' lifespans were shortened by 37–64%, compared to those mated with unmodified males.
Using computer models, the team predicts that applying TMT to an aggressive mosquito species primarily responsible for transmitting dengue and zika, could reduce blood-feeding rates by 40 to 60%.
That could go a long way towards curbing the spread of these diseases. In 2023, the World Health Organization estimated 263 million cases of malaria worldwide; the European Center for Disease Prevention and Control noted 14 million cases of dengue around the globe.
"We still need to implement it in mosquitoes and conduct rigorous safety testing to ensure there are no risks to humans or other non-target species," said Macquarie University associate professor Maciej Maselko, whose lab facilitated the proof-of-concept study.
Source: Macquarie University via Scimex
