Scientists mapped every cell of the world’s most dangerous animal

The mosquito might seem harmless, yet it ranks among the most dangerous creatures on Earth.

The species Aedes aegypti is especially notorious, transmitting diseases such as dengue, Zika, chikungunya, and yellow fever – infections that sicken millions and claim hundreds of thousands of lives each year.

Now, researchers from Rockefeller University’s Laboratory of Neurogenetics and Behavior have built the first-ever detailed map of this mosquito, down to the level of individual cells.

That means scientists can now look inside every part of the mosquito’s body and see what each cell is doing. It’s a bit like getting the instruction manual for a very tiny, very dangerous machine.

The danger behind the bite

Aedes aegypti isn’t just any mosquito. It’s the one that passes around more human disease than any other species of mosquito. That makes it a serious global health problem.

Scientists have studied it for decades, but until now, they’ve only been able to look at bits and pieces of its biology.

One study might focus on the brain. Another might look at the legs or antennae. But there was never a full picture of what’s happening in its body at the cellular level.

That changed when a team of scientists – working with mosquito experts around the world – released the Mosquito Cell Atlas.

The atlas shows what genes are active in every tissue, in both male and female mosquitoes. And it’s free for anyone to explore, from scientists to the simply curious.

Mapping every mosquito cell

“This is a comprehensive snapshot of what every cell in the mosquito is doing as far as expressing genes,” said Leslie Vosshall, who has been studying Aedes aegypti for nearly twenty years.

“It’s a real achievement because we profiled so many different types of tissues in both males and females.”

The Mosquito Cell Atlas catalogs over 367,000 cell nuclei drawn from 19 different tissues.

The samples span five major biological themes: the mosquito’s body structure, sensory systems for detecting hosts, immune responses to infection, reproductive organs, and the central nervous system.

“This enormous data set will really move mosquito biology forward,” said senior scientist Nadav Shai. “It’s a great tool for vector biologists to take whatever interests them and just run with their own line of research.”

Male mosquitoes join the map

In past research, scientists focused mainly on females. That makes sense: females are the ones that bite humans and spread disease. But males are part of the story too.

Both sexes feed on nectar for daily survival, but only females need blood to make eggs. Still, males have been left out of many studies.

“Because the female is the one that’s spreading all the pathogens, there is an enormous bias toward looking at the biology of the female and very little information about the male.” said Shai.

“We also wanted to bring the mosquito cell biology up to date in a single resource using advanced and uniform sequencing technology,” said Vosshall.

So the team made sure to include both sexes in their atlas. That decision led to some unexpected discoveries.

How mosquitoes taste the world

The researchers identified 69 different types of cells, sorted into 14 larger categories. Many of these cell types had never been seen before.

One of the most surprising findings was how many sensory neurons were spread throughout the mosquito’s body. These cells can detect temperature, taste, and other signals from the environment.

Scientists knew they were in the antennae and mouthparts. But now they’ve found them in other places, like the legs.

“Just like the antennae and maxillary palps, the legs and mouthparts have really powerful tools for sensing the world,” Shai said. These tools help mosquitoes find food, water, and places to lay eggs.

“Being able to taste sweetness with their legs may be useful for detecting sugars, which both females and males need to live,” he said.

“But it’s just one part of a combination of tastes that clues them into what’s around them – a human to bite, a flower for sugar source or a good water source to lay eggs. We believe that the combination of a lot of sensors is important for their survival.”

Big changes in the mosquito brain

A female mosquito behaves very differently before and after taking a blood meal. Before feeding, she hunts. After feeding, she turns her attention to making and laying eggs. What flips that switch?

“We knew from previous research from our lab and others that the brain transcripts change after blood feeding,” Shai said. “Our assumption was that maybe we would find different subtypes of neurons that down- or upregulated their transcripts.”

They studied female brains at different time points after blood feeding – 3, 12, 24, and 48 hours. They found major shifts in gene activity, especially in the first few hours.

The surprise came when they saw which cells were changing. Even though neurons make up about 90 percent of the mosquito brain, it was the glial cells – support cells that make up less than 10 percent – that showed the biggest changes.

“The glia are completely rewired during this time when the females lose interest in people,” Vosshall said.

“That was a big surprise,” Shai said. “It’s evidence that glia are super important for not only supporting brain cells and function but also are physiologically relevant to behavior.”

Two sexes, one blueprint

Mosquitoes have very different roles depending on their sex. Females bite, lay eggs, and carry disease. Males don’t. But when the team looked at the cells in both sexes, they found more similarities than differences.

“We were kind of expecting it to be a tale of two genomes, but that’s not what we found,” Vosshall said.

“In general, most cells look the same, and the transcripts they express are similar,” Shai said.

There were a few exceptions, like a small group of cells in the male antenna that didn’t exist in females. But overall, the male and female cell maps lined up closely.

A new era for mosquito research

The research team isn’t finished. They plan to use this data to study more mosquito behaviors, including how they track humans and choose where to lay eggs. Each lab member will explore different parts of the atlas to learn more.

“The sheer size of the dataset opens up many new avenues of research that people couldn’t study before because they didn’t have this tool,” Shai said.

“This is a global resource that has been open to everyone since the very inception of the project in 2021, so many people are already using it,” Vosshall said. “We’re excited to see the discoveries that will come from it.”

The full study was published in the journal Cell.

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