Why Hawaii Is Dropping Millions of Mosquitoes from the Sky

Mosquitoes are a problem in just about every country around the world. Not only are they annoying as they buzz around looking for their next victim to bite, but they carry a variety of diseases that infect people and animals alike.

Instead of attempting to decrease the population of mosquitoes, Hawaii is taking a different approach by having mosquito capsules dropped from Hawaiian skies. This may seem odd, as it involves adding mosquitoes to the environment. However, the overall goal is to eradicate mosquito populations to stop the spread of avian malaria, which has led to the demise of honeycreepers to the point where the songbirds are near extinction.

How Mosquito Capsules Could Save Songbirds

Songbirds known as honeycreepers are hanging on by a thread in Hawaii. These birds, once abundant on multiple Hawaiian Islands have had their population numbers severely decimated as a result of biting mosquitoes infecting the honeycreepers with avian malaria.

Avian malaria causes the honeycreepers to lose red blood cells. As the cells are lost, oxygen movement through the body slows. The birds become more lethargic, lose their appetites, and eventually die.

It was not until mosquitoes were introduced to the Hawaiian Islands more than two centuries ago that avian malaria existed. The fallout from avian malaria has resulted in the extinction of 32 species of honeycreepers. Of the 18 that remain, six are on the brink of extinction.

To combat this, drones are being used to drop male mosquitoes into honeycreeper environments from the air. Millions more mosquitoes are now in the honeycreeper environment than ever before. The difference is that these mosquitoes do not bite. However, they want to procreate, which is what female mosquitoes aim to do to produce mosquito larvae, and this is precisely what scientists hope happens.

Sterilized Mosquitoes

It may seem counterintuitive to release millions of mosquitoes into the honeycreeper environment, given that they are the very insects that cause the birds to become infected with avian malaria. But these are not just any mosquitoes. The mosquitoes being dropped are male southern house mosquitoes infected with a different strain of Wolbachia bacteria, which makes them effectively sterile by causing any eggs they fertilize to be non-viable.

The male southern house mosquitoes being raised in labs are sterile. This means there is no way for the female mosquito eggs to be fertilized. The hope is that by introducing 40 million male mosquitoes into the honeycreeper habitat over the past couple of years, the number of mosquito larvae born will be decreased. The fewer larvae hatched means the fewer number of potential mosquitoes that make it to adulthood.

The idea of releasing sterile male mosquitoes to save the honeycreepers originated from the same approach used to disrupt mosquito populations that spread diseases in humans. The results from these studies have thus far proven to be successful. Therefore, the hope is that the same positive results will be realized for the honeycreepers, and they will be saved from the mosquitoes and avian malaria.

Mosquitoes Are Not Native to Hawaii

Given their remote location, mosquitoes should never have been able to reach any of the Hawaiian Islands. However, in the 1800s, when the islands started to be inhabited by those from the mainland, mosquitoes were transported to Hawaii.

It is believed that as supplies and food were brought to Hawaii, from both the United States as well as other Pacific Islands, mosquitoes were in said packages. Having survived the journey to Hawaii, once the mosquitoes were accidentally set free, they found an environment that was hospitable and began to thrive.

It was not long before mosquitoes were found on every Hawaiian island. Thanks to the lush environments, there was plenty of standing water for mosquito eggs to be laid in. The temperature is warm enough as well that mosquitoes live year-round.

To date, eight distinct types of mosquitoes inhabit Hawaii. The most common of which are the Asian tiger mosquito and the southern house mosquito. Of the species, six bite, while the other two eat plants. Not only are mosquitoes harmful to the honeycreepers and other songbirds in Hawaii, but they also spread disease among people.

The diseases that mosquitoes spread to people in Hawaii include:

• Zika

• Dengue

• West Nile

• Malaria

• Yellow Fever

• Chikungunya

Therefore, it is not only honeycreepers that need to worry about diseases from mosquitoes. Visitors to the Hawaiian Islands should ensure they are adequately protected from mosquitoes. The best way to do this includes:

• Wearing a long shirt and pants to protect the skin

• Stay indoors during peak mosquito hours

• Use insect repellent

• Close windows at night

• Ensure there is no standing water

Most are not going to wear long pants and shirts while in Hawaii. However, by following any of the recommended tips, the chances of being bitten by mosquitoes decrease, as does the possibility of contracting a mosquito-carried disease.

Honeycreepers Could Go Extinct in the Next Decade

Honeycreepers have been a part of the Hawaiian Islands for over seven million years. Despite thriving since the islands of Kauai and Ni’ihau were new, it has taken only a couple of centuries to decimate the population of these incredible songbirds, who may soon become extinct.

Despite mosquitoes being introduced to Kauai in the 1800s, the honeycreepers were not immediately affected. This is because the birds tend to live in higher mountainous areas of the island. These regions are cooler and less habitable for mosquitoes compared to the lower, warmer elevations.

However, climate change has increased temperatures on the islands, including those in higher elevations. Consequently, the regions where the honeycreepers live were no longer safe. Avian malaria began to take hold in the 1940s and has worsened in more recent decades.

Some experts believe that if avian malaria is not brought under control soon, according to Mongabay, which means eradicating the mosquitoes that spread it from Kauai, the honeycreepers could become extinct within 30 years. Others state the timeline is much shorter, and the songbirds could be essentially extinct in as little as a decade.

Despite the differences in timelines, what is clear is that the honeycreepers’ lives hang in the balance. Whether dropping mosquito capsules will prove to be effective enough to stop the southern house mosquito from reproducing and spreading avian malaria remains to be seen. But the hope is that between vector control and dropping sterile mosquitoes into the environment, enough time will be given to the birds to be able to recover their populations versus continuing to see them decline.

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