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, because there are different mosquito species in Hawaiʻi and multiple tools that could be used for mosquito control, this topic can get confusing. 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.

Is this “birth control” method commonly used to control mosquitoes, or has it been used previously?

Yes, this method has United States Environmental Protection Agency (EPA) approval for Aedes aegypti mosquitoes. It is currently being used elsewhere in the U.S. and other countries to reduce mosquito populations and disease transmission while enhancing public health and quality of life. A similar method has been used safely and effectively to control fruit flies in Hawaiʻi.

 Are Wolbachia-incompatible mosquitoes the same as genetically-engineered ones? 

No, they are not the same. The development of genetically-engineered and Wolbachia-incompatible mosquitoes have the same purpose but use different mechanisms to suppress mosquito reproduction in the wild. There is no modification of any gene in the mosquitoes or Wolbachia for the birth control method.

 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.

 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.

 How do you make sure you are only releasing male mosquitoes? 

Mosquitoes can be separated by sex using a number of techniques. Males and females are different sizes at various life stages with females being larger. One technique filters out females using a “grating” system that only allows the smaller male pupae to fall through. There is also Artificial Intelligence technology that can scan the pupae and adults and separate them by sex.

 When do you plan to release the mosquitoes? 

We hope to conduct small-scale trials in 1 -2 years. The larger-scale releases could happen in 2 - 4 years. (last update: 2/2022.)

 What has to happen before you release any male Wolbachia-incompatible mosquitoes? 

We have to comply with all state and federal regulations, including permit requirements, and ensure that the public knows about the project and has the opportunity to provide input.

 Will the Wolbachia bacteria affect other mosquitoes? And how do you know? 

The Wolbachia bacteria won't affect other insects or any other species. Wolbachia is maternally transmitted, meaning it can only be passed down from mothers to their offspring.

 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.