Oldest mosquitoes frozen in amber 130 million years ago reveal a ‘bloodsucking surprise’ that changes how scientists look at insects

The oldest known mosquito fossils have revealed a 'blood-sucking surprise'.

The remains of two males frozen in amber 130 million years ago showed elongated piercing and sucking mouthparts now only seen in females – the only ones that bite.

The discovery is a “key discovery in the evolutionary history of mosquitoes,” according to the team's lead paleontologist.

These scientists argued that the male specimens suggested an unexpected origin story for blood-sucking mosquitoes: the insect may have evolved from a plant-sucking plant-sucking ancestor.

Researchers reported this week that the samples were discovered in Lebanon, near the town of Hammana

Researchers reported this week that the samples were discovered in Lebanon, near the town of Hammana.

“They were clearly blood-eaters,” said paleontologist Danny Azar of the Chinese Academy of Sciences, the Nanjing Institute of Geology and Paleontology and the Lebanese University.

“In all blood-eating insects, we believe that blood-eating was a switch from sucking plant fluid to sucking blood,” Azar said.

Plant evolution may have played a role in the difference in nutrition between male and female mosquitoes as well, according to Azar, who served as lead author of the new study, published this week in the journal. Current biology.

When the two male mosquitoes became stuck in tree sap that eventually turned amber, according to Azar and colleagues' analysis, flowering plants began to flourish for the first time along the landscapes of the Cretaceous world.

The fact that the oldest known mosquito species are blood-sucking males “means that originally the first mosquitoes were all blood-eaters — regardless of whether they were male or female,” Azar added.

Azar and his team said they suspect that ancient mosquito mouthparts adapted for obtaining blood meals were originally used to puncture plants to access nutrient fluids — and in some, they evolved back into plants.

Azar speculated in a statement to Reuters that “hemophagy was lost later in males, perhaps due to the emergence of flowering plants that coincided with the formation of Lebanese amber.”

The researchers said they suspect that ancient mosquito mouthparts adapted for obtaining blood meals were originally used to puncture plants to obtain nutrient fluids, and in some they evolved again. “Maybe because of the appearance of flowering plants.”

Today, hundreds of thousands of people are killed around the world every year by malaria and other diseases spread by mosquito bites, all of which are female bites.

“Mosquitoes are among the most well-known blood feeders of humans and most terrestrial vertebrates, and they transmit a certain number of parasites and diseases to their hosts,” Azar said.

The scientist pointed out that “only fertilized female mosquitoes suck blood because they need proteins to develop their eggs.”

“Unfertilized males and females will eat some nectar from plants. Some males do not feed at all,” he added.

While some flying insects — the tsetse fly, for example — have blood-eating males, modern mosquitoes, which number about 3,500 species worldwide, do not have males.

“Finding this behavior in the Cretaceous period is very surprising,” paleontologist and study co-author Andre Niel of the National Museum of Natural History in Paris told Reuters.

The precise anatomy of Cretaceous-era mosquitoes was beautifully preserved in the fossils, the researchers noted.

Both showed exceptionally sharp anatomy of the triangular-shaped jaw and an elongated structure with tooth-like projections.

Lots of animals would have existed to provide blood meals for these specimens: everything from dinosaurs to flying reptiles called pterosaurs to other reptiles, birds and mammals.

The researchers said that these are the oldest mosquito fossils currently, but this type of insect may have originated millions of years ago.

They noted that molecular evidence suggests that mosquitoes originated about 200 million to 145 million years ago during the Jurassic Period.

Today, modern mosquitoes are found everywhere except Antarctica.

Some of them become disease vectors that transmit malaria, yellow fever, Zika fever, dengue fever and other diseases. According to the United Nations World Health Organization, more than 400,000 people die annually from malaria, a parasitic infection, most of them children under the age of five.

But “on the other hand, mosquitoes help purify the water in ponds, lakes and rivers,” Neal noted. “In general, an animal can be a problem but it can also be beneficial.”