Mosquitoes kill more humans than any other single organism, by far. The insects transmit malaria, dengue fever, yellow fever, the Zika virus and other diseases to millions of people every year. Malaria alone kills over 400,000 people per year, mostly children, and as climate change provides the insects with hospitable new habitats, including in the US and Western Europe, the death toll will continue to rise.
Now an Israeli startup, Senecio Robotics, has unveiled a plan to combat the menace by efficiently mass producing and dispersing sterile mosquitoes by the planeload, potentially saving millions.
The “sterile insect technique” for pest control dates back to the 1950s. Artificially sterilized insects, usually males, are released into the wild population in overwhelming numbers. When these sterile males mate with wild fertile females, the females do not produce offspring, disrupting their reproductive cycle. The technique has been successfully deployed against various species of moths and flies, reducing disease and damage to humans and agriculture.
Mosquitoes are another story. They are more fragile than moths or flies, making them difficult to store and transport in large numbers, and are difficult to sort by gender. Senecio’s technology aims to solve these problems by automating the sorting process, and allowing for the storage and dispersal of massive numbers of the insects.
Female mosquitoes bite; males do not. Males only live for about a week and some species (there are 2,700 mosquito species) only stray around 100 meters from their birthplace during their lives, so for the technique to be effective, huge numbers of sterile males need to be dispersed weekly to triumph over wild males — as many as 10 sterile males per wild male, and as many as 800 mosquitoes per person in the target area. Millions per week might cover a small neighborhood, while hundreds of millions per week would be needed to cover a city, said Senecio Robotics CEO Hanan Lepek.
Chemical control is costly, harmful to the environment and ineffective, Lepek said. Mosquitoes develop resistance to chemicals quickly because of their short lifespan.
Meanwhile, the sterile insect technique uses the insects’ natural behavior against them to suppress the population in an environmentally friendly way.
“This is their nature. They’re trying to look for females. They’re like smart bombs,” Lepek said. “You have a tool that is very precise, unlike chemicals, so there is zero collateral damage.”
Lepek founded the company in 2013 with the goal of automating and streamlining the sorting, packaging and release of male mosquitoes.
“We saw the problem of the mosquitoes and we assumed that in a few years, when people would actually want to manufacture and release those mosquitoes in large numbers, there will be some problems,” said Lepek, whose background is in aerospace technologies. “So we thought that if someone really wants to solve and address epidemics by mosquitoes such as Zika and dengue, yellow fever, on a large scale, then you need to bring some tools for mass production and mass release,” Lepek said.
The company does not produce or sterilize mosquitoes itself, but plans to automate the gender sorting of the insects with local partners who will handle the production. Until now, the bugs have been sorted mechanically. Males and females are different sizes as pupae, so workers painstakingly sort them with a glass sieve. The work is slow, labor intensive and not accurate enough, Lepek said. At such a large scale, even a small percentage of females getting through will add a significant number of biting insects to the wild. Also, the species of mosquito that carries malaria shows no size differences at any stage, Lepek said.
Senecio’s “BioMosquito” technology, which the company revealed last month, automates the sorting process using imaging technology, artificial learning and machine learning. The company’s computers learn to differentiate automatically between male and female mosquitoes.
After sterilization, the male and female mosquitoes are immobilized through a chilling process, and are dispersed onto a conveyor, like a conveyor belt for pharmaceutical production. The conveyor slowly cycles the mosquitoes through a high resolution camera, which takes photos of roughly 100 insects at a time. The computer identifies which mosquitoes are male and which are female, and that information is sent to the next station on the conveyor, where robotic arms with suction mechanisms on the ends remove and kill the immobile females individually. Multiple cameras and conveyors, moving slowly but continuously around the clock, can churn out millions of sterile male mosquitoes per day, Lepek said.
Above: Senecio’s technology can identify and track individual mosquitoes.
At the end of the conveyor, a blower inserts the mosquitoes into cartridges. Put too many mosquitoes into a container together and some suffocate, and their legs get tangled, like Velcro, Lepek said, so the bugs have to be either be chilled and immobilized, or unchilled and packed together less densely. An unchilled cartridge can hold about 1,000 mosquitoes, while a chilled one can hold hundreds of thousands. The mosquitoes that are chilled, however, die sooner in the wild and are less competitive with the wild males, depending on how long they are kept cold, so the storage method depends on the means of dispersal.
The insects can be released via airplane, drone or ground vehicle. Planes can disperse the most mosquitoes, around 10 million per flight, over the widest area but present a problem because of the insects’ fragility. A blast of 150 mile per hour wind will severely damage them, so they cannot be spilled directly from the plane, which is possible with drones and ground vehicles.
Senecio Robotics’ aircraft release mechanism is a specially designed pod that fits under the belly of the plane. The mosquitoes’ release from their cartridge is synchronized with a puff of air. The shape of the pod and the flow of air behind it, plus the air puff, create a more gentle flow of air for the mosquitoes when they exit the cartridge. The air flow then accelerates, so they are not hit by the full impact of the plane’s speed. It’s like the difference between holding your hand outside a car window while it accelerates and sticking your hand out while speeding on the highway.
The release mechanism has been successfully tested in the US. The company caught mosquitoes it had marked with a fluorescent powder and released from the plane on the ground and put them in a control group with wild mosquitoes. The two groups lived the same amount of time.
The company is partnering with the Virginia-based Dynamic Aviation Corporation, which has a fleet of aircraft that can carry the mosquito pods. They are developing and testing their “BioMosquito Factory,” doing research and development on the sorting and packaging process, and have received patents for the release system in multiple countries, Lepek said. Together with Dynamic Aviation, the company won a grant from the BIRD Foundation. Their initial focus will be on the United States and Brazil, and later, they may look to deploy their technology in Singapore, China and Africa. They plan to have the system completed by next summer.