In a significant step in conservation efforts, researchers on Kaua‘i have released hundreds of thousands of specially-bred mosquitoes to help protect the island's forest birds from extinction. The Kaua‘i Forest Bird Recovery Project (KFBRP), after a decade of planning, securing permits, and conducting community outreach, has begun deploying male mosquitoes that are genetically engineered to be reproductively sterile. The goal is to reduce the population of mosquitoes carrying avian malaria parasites, as reported by the Department of Land and Natural Resources (DLNR).
The approach uses Incompatible Insect Technology (IIT), a method previously employed to reduce human malaria cases worldwide. This marks its first use on Kaua‘i to combat a disease that has significantly impacted native Hawaiian honeycreeper populations. The process involves dispersing biodegradable cones containing half a million male mosquitoes via helicopter over the Alakaʻi Plateau twice a week. As these modified mosquitoes mix with the wild population, they disrupt the lifecycle of female mosquitoes that spread the disease. "We do this twice a week to ensure there’s a very, very high likelihood that a wild female will encounter one of the incompatible males," Dr. Lisa ‘Cali’ Crampton, head of KFBRP, said in a statement obtained by the DLNR.
Complementing the IIT tactic, the KFBRP employs another method known as BTi larvicide, which specifically targets the mosquito larvae. This two-pronged strategy of integrated pest management - attacking both larvae and adults, and intervening in egg production, enhances the odds of female mosquitoes meeting sterile mates, thus amplifying the overall effectiveness of the mosquito population suppression effort. This results in “the idea is the BTi reduces populations of adult mosquitoes to begin with, making it more likely that females will encounter one of these incompatible males,” as Crampton told the DLNR.
The future of Kaua‘i's endangered bird species, such as the ‘akikiki and the ‘akeke’e, which are at risk of disappearing from the wild, now relies on the success of these control measures. The objective is that, after using IIT and BTi for a sufficient period, conservation-bred birds or their offspring may one day return to a mosquito-reduced environment and thrive in their natural habitat on Kaua‘i. Dr. Crampton outlined the role of conservation breeding populations in supporting the continued existence of these birds.
