The Lee County Mosquito Control District has reached a new milestone, becoming the first to release sterile mosquitoes by drone.

Rachel Morreale, manager of the Lee County Mosquito District sterile insect technique program, said that the drone will release mosquitoes more effectively by reaching areas the district couldn’t before.

“The reason why we like the drone and why it’s so beneficial is that it helps us get a better distribution of these mosquitoes,” she said. “Before we were stuck with whatever we could access by road, so having this drone means that we can actually put the mosquitoes in places where they want to be and get a better even spread of mosquitoes all around.”

Lee County Mosquito District uses a Skydio X10 drone. The drone’s release cassette can carry up to 35,000 mosquitoes.

“We can compact them (mosquitoes) down and they handle it quite well,” Morreale said. “But we don’t release that much in one spot ever. We would spread that around so that that cassette would be moving over quite a large area.”

According to Skydio’s official website, the drone can fly at a top speed of 45 mph and has a maximum flight time of 40 minutes.

“We’ve actually had really good results out of our drone release so far,” Morreale said. “I’m very positive that this method is very good and low impact for these mosquitoes.”

The operation is part of the district’s sterile insect technique program, which aims to reduce the invasive Aedes aegypti mosquito population by releasing lab-raised, sterilized male mosquitoes that will mate with wild female mosquitoes, resulting in eggs that won’t hatch. Only male mosquitoes are released because they don’t bite like their female counterparts.

The district developed a strain of mosquitoes that is native to Captiva and Fort Myers. It’s a 10-day process to raise the mosquitoes to adulthood and then sterilize them using X-rays – the same ones humans receive during a doctor’s visit.

“This is our own homegrown local strain of mosquitoes that are being applied here,” Morreale said. “We have our own colony in the lab. From egg to adult, you’re looking at about a week and then we will irradiate the males once they’re fully emerged, and then release.”

Every sterilized mosquito is marked with a fluorescent powder that will help Lee County Mosquito Control District distinguish and measure the mosquitoes’ survival and recapture rates in the wild.

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