Robot sorts 16 million sterile mosquito soldiers every week to battle spread

A recent study has unveiled an automated pupae sorter capable of distinguishing and sorting millions of male and female mosquitoes daily. This innovation could boost current pupae separation rates by approximately 17 times and produce up to 16 million male mosquitoes a week.

The new technology promises to enhance efforts to reduce mosquito populations and combat mosquito-borne illnesses by facilitating the release of sterile or incompatible males to mate with wild females.

“The upscale of the use of these techniques is going to have very positive environmental impacts, since mosquito control is currently mainly based on the use of pesticides. Moreover, the targeted mosquito species are invasive species, and their control will reestablish ecosystem integrity,” Jérémy Bouyer, one of the study authors, told Interesting Engineering (IE).

Beyond manual sorting

Mosquito pupae are the stage in a mosquito’s life cycle just before they become adults. After hatching from eggs, mosquitoes first become larvae. As they grow, they transform into pupae, which look like little floating commas. When ready, the adult mosquito emerges from the pupal case, ready to fly and start the cycle again.

Mosquitoes are typically sorted by biological sex differences such as pupa size and development rate. Manual sorting methods, which are labor-intensive and time-consuming, often result in higher female contamination rates and limit the mass sorting of males.

To overcome this issue, Jun-Tao Gong and his team developed a fully automated device capable of loading, sorting, and collecting millions of male pupae daily. Tested on Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus mosquitoes , the automated sorter demonstrated reduced sorting time and lower female contamination rates compared to manual methods.

Bouyer explains, “Each species and strain has specific differences between sexes and these differences are also impacted by mass-rearing conditions. Our sorter does account for these differences since it is calibrated every day to optimize the sorting efficiency.”

Mass-producing sterile male mosquitoes

The device produced males with recovery rates and flight abilities similar to those sorted manually. In field tests in Guangzhou, China, the release of automatically sorted, incompatible A. albopictus males resulted in significant population suppression.

The authors propose that one person can manage multiple devices at the same time, producing up to 16 million male mosquitoes per week . They conclude that this approach could help solve the long-standing challenge of mass-producing sterile mosquitoes.

Bouyer told IE , “Our mosquito sorter is currently the fastest system leading to huge savings in terms of human workload. Moreover, the sorting system is based on the use of glasses which minimizes the friction to which the pupae are subjected thus producing high quality sterile males.”

“This high quality allows reducing the release density also leading to savings in money. The mosquito sorter has already been purchased by 5 countries currently upscaling the sterile insect technique against Aedes mosquitoes, including France, Italy, Mexico, and the USA.”

“The automated sorter may also be used to implement other genetic control methods based on the release of males only. All genetic control methods are very much compatible with the use of larvicides,” he concludes.

The study has been published in Science Robotics .