A Hawaii Department of Agriculture advisory committee approved proposals by the Department of Land and Natural Resources to import 208 million mosquitoes to the state per year.
The bugs are a last-ditch effort to save critically endangered birds on the Big Island, Maui and Kauai, where invasive mosquitoes have exposed them to avian malaria. The imported mosquitoes are a Trojan horse carrying a bacteria that renders them incapable of breeding.
DOA entomologist Chris Kishimoto explained during Thursday’s meeting of the DOA Advisory Committee on Plants and Animals that the 208 million mosquitoes the DLNR plans to import from a seller in California will be inoculated with a strain of the Wolbachia bacteria that is incompatible with the strain present in Hawaii’s mosquito populations.
The infected mosquitoes infected can only breed with those infected with the matching strain. When the imported mosquitoes — which will all be males, and will therefore not bite anything — encounter local populations, they will breed with local females, but the eggs will be nonviable.
Because the DLNR hopes to bring in 10 imported mosquitoes for every male in the wild, the imported bugs will all but replace local populations, Kishimoto said.
He added there is little risk of even a single female mosquito being accidentally shipped among the males.
Once the bugs are brought to the state, the DLNR could introduce groups of them to certain areas as many as three times a week through ground or aerial releases via helicopter, Kishimoto said.
Those areas will include “40,000 acres of state, federal and private wildlife conservation areas in the state,” but specific sites have yet to be determined based surveys of endangered bird populations.
Kishimoto added that the imported bugs will be treated with the Wolbachia strain but will be genetically descended from the Hawaii mosquito populations to ensure that they will not introduce new disease to the state.
Kishimoto said a similar program was carried out in Fresno, Calif., from 2017 to 2019, which reduced local mosquito populations by as much as 95%.
But before this can happen, the Board of Agriculture needs to approve adding three mosquito species to the state’s Restricted Animals List, which would allow the state to import the insects under certain conditions.
The advisory committee on Thursday unanimously approved the DLNR’s proposals with minor amendments, forwarding the matter to a future meeting of the full BOA.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.