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EPA Approves Release of Bacteria-Carrying Mosquitoes To 20 States (nature.com)
schwit1 writes: The U.S. Environmental Protection Agency (EPA) has approved the use of a common bacterium to kill wild mosquitoes that transmit viruses such as dengue, yellow fever and Zika, Nature's news team has learned. On November 3rd, the agency told biotechnology start-up MosquitoMate that it could release the bacterium Wolbachia pipientis into the environment as a tool against the Asian tiger mosquito (Aedes albopictus). Lab-reared mosquitoes will deliver the bacterium to wild mosquito populations. The decision -- which the EPA has not formally announced -- allows the company, which is based in Lexington, Kentucky, to release the bacteria-infected mosquitoes in 20 U.S. states and Washington DC.
MosquitoMate will rear the Wolbachia-infected A. albopictus mosquitoes in its laboratories, and then sort males from females. Then the laboratory males, which don't bite, will be released at treatment sites. When these males mate with wild females, which do not carry the same strain of Wolbachia, the resulting fertilized eggs don't hatch because the paternal chromosomes do not form properly. The company says that over time, as more of the Wolbachia-infected males are released and breed with the wild partners, the pest population of A. albopictus mosquitoes dwindles. Other insects, including other species of mosquito, are not harmed by the practice, says Stephen Dobson, an entomologist at the University of Kentucky in Lexington and founder of MosquitoMate.
MosquitoMate will rear the Wolbachia-infected A. albopictus mosquitoes in its laboratories, and then sort males from females. Then the laboratory males, which don't bite, will be released at treatment sites. When these males mate with wild females, which do not carry the same strain of Wolbachia, the resulting fertilized eggs don't hatch because the paternal chromosomes do not form properly. The company says that over time, as more of the Wolbachia-infected males are released and breed with the wild partners, the pest population of A. albopictus mosquitoes dwindles. Other insects, including other species of mosquito, are not harmed by the practice, says Stephen Dobson, an entomologist at the University of Kentucky in Lexington and founder of MosquitoMate.
(a) because breeding captive mosquitoes is not very difficult (though it's not pain free: mosquitoes require a blood meal to reproduce, which often involves a person sticking his/her arm in the cage)
(b) because if the "sterile males" are released in the right time and place, they outnumber the wild males, so *most* wild females mate with a sterile male; repeated a few times this can actually wipe out the wild population
(c) but as far as I know, separating captive males and females is not so easy
Source: I used to work in a tropical medicine institute (but not directly with any mosquitoes).