Disease control Sexuality separation apparatus for mosquitoes presented

With the mass sterilization of male mosquitoes, health authorities want to eradicate insects that transmit deadly diseases in affected areas. A new automatic sorting machine separates the male and female pupae.

As reported by an Austrian-Chinese research team in the journal "Science Robotics", millions of harmless males could be collected in this way without the risk of blood-sucking females.

In "Sterile Insect Technology (SIT)", male mosquitoes are bred in laboratories and rendered infertile using radiation. They are then released in large numbers to snatch away as many females as possible from the wild mosquito males. After copulation, the female mosquitoes lay eggs, but no mosquito offspring develop from them due to the infertile sperm.

A team led by Jeremy Bouyer from the "Insect Pest Control Programme" of the International Atomic Energy Agency (IAEA) and Food and Agriculture Organization (FAO) in Vienna and Zhiyong Xi from a biotech company in Guangzhou, China, developed an apparatus in which the differently sized pupae of the males and females are automatically separated.

The researchers tested it with three different mosquito species, namely yellow fever mosquitoes (Aedes aegypti), Asian tiger mosquitoes (Aedes albopictus) and "Culex quinquefasciatus" mosquitoes. They transmit yellow fever, dengue fever, Zika, chikungunya and West Nile viruses as well as parasitic worms.

With the automatic "sex sorter", one person can separate 16 million males per week, the researchers report in the specialist publication: "They then show good flight ability and mating performance." In a field trial in Guangzhou, the local tiger mosquito population was decimated by more than four-fifths using such automatically separated males.