Frequently Asked Questions
ʻakikiki © Zach Pezzillo
Landscape-scale control of mosquitoes using the Incompatible Insect Technique has the potential to safely reduce the number of mosquitoes in the forests of Hawaiʻi, reducing the likelihood that our forest birds will be impacted by avian malaria. However, this topic can get confusing because there are different mosquito species in Hawaiʻi and multiple tools that could be used for mosquito control. Once you’ve learned about the native forest birds of Hawaiʻi and the mosquito species that harm them, we recommend learning about the non-genetic Incompatible Insect Technique being explored by project partners in Hawaiʻi, as well as understanding the potential genetic tools that are not being explored by the project at this time. This information helps provide context about what is and what is not being worked on under the current scope of this project. We’ve also provided answers to Frequently Asked Questions, which you can read below or download in our project flyer.
What do mosquitoes have to do with the native birds of Hawaiʻi?
The native birds of Hawaiʻi have evolved in the absence of mosquitoes and avian malaria. Introduced bird species have high degrees of immunity to avian malaria and can continue living alongside mosquitoes at low elevations, but our native birds are more susceptible to the disease. Twenty-six species of honeycreepers have gone extinct in Hawaiʻi since the first arrival of Europeans, with many extinctions linked to disease. Most of the remaining native forest birds are now only found at high elevations where it is too cold for the southern house mosquitoes and the avian malaria parasite. As our climate warms, mosquitoes are moving to higher elevations, and the available habitat for our native forest birds is disappearing.
What is Incompatible Insect Technique?
The Incompatible Insect Technique interrupts mosquito reproduction and is used to reduce insect populations. It functions like birth control by making it impossible for male mosquitoes to produce viable offspring. Most mosquitoes (and many other insects) carry a type of bacteria called Wolbachia in their system. This bacterium “hacks” the reproductive system of its hosts and modifies the sperm from infected male mosquitoes, creating a timing mismatch in the embryo’s development after fertilization, and causing the eggs to fail to hatch. But if the male and female carry a compatible strain of Wolbachia, a genetic factor in the infected egg can reverse or neutralize the modification, leading to viable eggs. If males and females carry incompatible strains of this bacteria, eggs laid by the female won’t hatch. Males and females must carry the same Wolbachia strain in order to reproduce.
Are Wolbachia-incompatible mosquitoes genetically-modified?
No, they are not. There is no gene modification in the mosquitoes or Wolbachia using the birth control method.
Can this have an adverse effect on the overall environment?
Suppressing mosquitoes should not have an adverse effect on the overall environment in Hawaiʻi. Our native birds, plants, and insects evolved over millions of years without mosquitoes, which were first introduced to Hawaiʻi about 200 years ago. As a result, they are not a significant part of the diets of any native species, aren't needed to pollinate native plants, and don't serve any other known ecosystem function in Hawaiʻi.
How will male and female mosquitoes be sorted prior to release?
Mosquitoes can be separated by sex using several techniques. Males and females are different sizes at various life states, with females being larger. A technique filters out females using a mechanical sieving system that only allows the smaller male pupae to fall through. Another techniques uses artificial intelligence technology to scan the adults and separate them by sex. Ongoing monitoring will occur for quality assurance and control in both the lab and release environments.
What has to happen before you release any incompatible male mosquitoes?
Numerous state and federal regulations will have to be complied with, including permit requirements, that ensure that the public knows about the project and has the opportunity to provide input. This will include discussions with communities and opportunities to provide feedback, including comments on formal compliance documents like Environmental Assessments.
Where else has this "birth control" method been used to control mosquitoes?
This method is currently being used worldwide and in the continental US to reduce populations of yellow fever mosquitoes (Aedes aegypti) and Asian tiger mosquitoes (Aedes albopictus) for public health and quality of life. Both mosquitoes are found in Hawaiʻi and can spread human diseases such as dengue, chikungunya, and the Zika virus.
Can this “birth control” process be reversed?
Yes. Since this tool is not self-perpetuating in the wild, we can reverse the process simply by no longer releasing male mosquitoes carrying the incompatible strain of Wolbachia. The lifespan of the mosquitoes would thus serve as a self-limiting mechanism of this technique.
When do you plan to release the mosquitoes?
It is anticipated that small-scale field trials will be conducted in 2023 - 2024. Following field trials, large-scale landscape releases would begin in 2024.
Will the project happen fast enough to save our birds?
We don't know if it can happen fast enough to save all our birds. Based on recent field data, some of the native honeycreepers on Kauaʻi and Maui may have only 2 - 3 years before extinction. That's why this project is so urgent. We want to stop the loss of more species.
How long will the released mosquitoes live?
The lifespan of a southern house mosquito is up to six weeks, with females outliving males. The released incompatible males are expected to live less than two weeks and thus will not persist in the environment.
How do you know it's safe and won't affect other species of humans?
If the incompatible strain is developed in a lab, its use is considered a biopesticide; any release of males requires rigorous testing and registration with the Environmental Protection Agency to demonstrate its safety and effectiveness. If release of a naturally-incompatible mosquito is planned, it would be considered a biological control agent and its use must be approved by the Hawaiʻi Department of Agriculture. These public processes require the applicant to address any potential environmental and human health safety issues. There is also no conceptual mechanism for this technique to harm humans or other species beyond the targeted mosquito species.