.png)
FREQUENTLY ASKED QUESTIONS
Wolbachia-incompatible male mosquitoes applied across large landscapes have the potential to safely reduce the number of mosquitoes in the high-elevation forests of Hawaiʻi, decreasing the likelihood that our forest birds will go extinct due to 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.
We’ve provided answers to Frequently Asked Questions below.
What do mosquitoes have to do with the native birds of Hawaiʻi?
Hawaiʻi's birds evolved in geographic isolation without mosquito-borne diseases such as avian pox and avian malaria. Following the introduction of mosquitoes in the 1800s, avian malaria contributed to severe declines and the extinctions of 23 species of honeycreepers. As our climate warms, mosquitoes are moving to higher elevations, and the mosquito free habitat for our native forest birds is disappearing rapidly.
A female mosquito bites the vulnerable skin of an 'i'iwi, potentially transmitting fatal avian malaria.
How is BNM working to stop extinction and reverse population declines?
BNM partners are working together to protect Hawaiʻi’s native birds through an integrated mosquito management and forest conservation approach. This includes habitat restoration, captive breeding, and mosquito suppression methods including the use of bacterial larvicides like Bti. We also do conservation and community engagement to help residents learn about our native birds and share ways the public can help.
What’s the status of the Incompatible Insect Technique (IIT)?
Read our project update!
Does the Incompatible Insect Technique involve genetic modification?
No, the proposed technique does not modify any part of the genome of either mosquitoes or the Wolbachia bacteria.
What is Bti?
Bt (Bacillus thuringiensis) is a naturally occurring bacterium found in soils around the world. Certain strains of this bacterium produce spores and protein crystal toxins that kill insect larvae when ingested. These strains have been developed into biological pesticides, or biopesticides, worldwide.
Different strains of Bt affect different groups of invertebrates. One strain, Bacillus thuringiensis subsp. israelensis (Bti), is an effective tool developed for use to control mosquitoes and closely related Diptera (fly) groups. Unlike broad-spectrum chemical insecticides Bti, when used according to the label, presents less environmental risk when applied aerially on a landscape-level scale. Additionally, it does not persist in the soil or water.
Is BNM using Bti to suppress mosquitoes?
Yes! And we have been for the last six years over on Kaua‘i where our partner, the Kaua‘i Forest Bird Recovery Project has been treating mosquito pools in the Alaka‘i. In the fall of 2026, BNM will expand Bti to critical habitat on Maui where we will be aerially treating native forests.
Why aerially deploy it?
Distributing Bti by helicopter is a way to deliver the biopesticide to mosquito pools and streams that are not feasible to hike to and treat by hand. The droplets from aerial liquid application are able to reach between vegetation in the forest as they fall to the ground, which means more pools and smaller habitats are able to be treated.
Yes to all of the above! When used according to the label, Bti is only harmful to certain insect species (mosquitoes and other closely related flies in the sub-order of Diptera)..
Is Bti safe? For people? Pets? Native wildlife?
Will Bti accumulate in our headwaters?
No, BT breaks down rapidly under UV light and does not multiply in water.
And how long does it last in the environment?
Bti is available in a granule and liquid form. It breaks down in granule form after 4 weeks and in liquid form after 1 week.
And is it true I can buy it for home application?
Yes! Often referred to as ‘dunk’, it is available at hardware stores and can be used to treat standing water around your home to kill mosquito larvae and prevent the emergence of biting adults.
Will reducing mosquito populations have any ripple effects in Hawai‘i?
No. None of our native or agricultural crops are pollinated by mosquitoes and none of our native birds, fish or even our native bat, rely on mosquitoes as a food source.
How is Bti different from Mosquito Birth Control (Incompatible Insect Technique)?
This method is separate from but complementary to IIT. BTi is a bacteria that kills mosquito larvae through production of a small protein. The Incompatible Insect Technique, also known as mosquito birth control, uses a different bacteria for a different purpose. In IIT, different strains of a bacteria called Wolbachia prevent male and female mosquitoes from laying viable eggs.
Why are you using multiple mosquito control methods?
We use multiple tools to suppress invasive mosquitoes and protect our native birds because there isn’t a single ‘silver bullet’ solution currently available and no time to wait for one. Multiple honeycreeper species may go extinct in the next 1-5 years primarily due to diseases carried by invasive mosquitoes. While we continue to plan for future projects using new techniques, we are stepping up the use of our existing tools in order to give our birds a better chance at avoiding extinction.
Researcher in a native forest (PC:MFBRP)
Will the project happen fast enough to save our birds?
'Akikiki, a Kaua'i endemic, are functionally extinct in the wild as of 2024 (above). Mosquito-borne diseases decimated their population. 'Anianiau (right) are also declining quickly. PC: Jum Denny
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 two to three years before extinction. That is why this project is so urgent. We want to stop the loss of more species.
