[1/2]An undated view from below of a fossilized male mosquito head containing elongated mouthparts with holes for sucking, encased in approximately 130 million-year-old amber found in central Lebanon. handout image. Handout via Dany Azar/Reuters Obtaining license rights
WASHINGTON, Dec 5 (Reuters) – Hundreds of thousands of people around the world die each year from malaria and other diseases spread through the bites of mosquitoes, insects that date back to the time of the dinosaurs. All of these bites are caused by females, who have specialized mouth structures that males do not have.
However, this was not always the case. Researchers have announced that they have discovered the oldest known mosquito fossil. These are two male mosquitoes buried in 130-million-year-old amber from the Cretaceous period, found near the town of Hammana in Lebanon. Surprisingly, the male mosquito had elongated piercing and sucking mouthparts that are now only found in females.
“They were clearly bloodsucking,” said Dany Azar, a paleontologist at the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences and the University of Lebanon, and lead author of the study published this week in an academic journal. current biology. “This discovery is therefore important in the evolutionary history of mosquitoes.”
The fossilized mosquitoes, both from the same extinct species, are similar in size and appearance to modern mosquitoes, but the mouthparts used to collect blood are shorter than those of modern female mosquitoes.
“Mosquitoes are the most notorious blood suckers of humans and most terrestrial vertebrates, transmitting a number of parasites and diseases to their hosts,” Azar said.
“Only fertilized female mosquitoes will suck blood because mosquitoes need protein to develop their eggs. Males and unfertilized females will eat some of the nectar from the plant. Some males don’t eat at all,” Azar added.
Some flying insects (such as the tsetse fly) have blood-sucking males. However, modern mosquitoes are not like that.
“It’s very surprising to find such behavior in the Cretaceous,” said paleontologist and study co-author Andre Nel of the National Museum of Natural History in Paris.
The delicate anatomy of the two mosquitoes was beautifully preserved in the fossils. Both exhibited very sharp triangular jaw anatomy and elongated structures with tooth-like projections.
Researchers said they believe mosquitoes may have evolved from insects that do not feed on blood. Researchers hypothesize that the mouthparts adapted for blood feeding may have originally been used to puncture plants and access nutrient-rich fluids.
Plant evolution may have played a role in the feeding divergence between male and female mosquitoes. While his two mosquitoes became trapped in the sap, which eventually turned amber, flowering plants were beginning to flourish on the Cretaceous Earth’s surface for the first time.
“In all blood-sucking insects, we think the blood meal was a transition from feeding on plant fluids to feeding on blood,” Azar said.
Azar further added that the fact that these earliest known mosquitoes were blood-sucking males suggests that “the first mosquitoes, male or female, were all originally blood-sucking, and perhaps the emergence of flowering This means that the blood-sucking ability was later lost in males.” It is a plant contemporary with the amber formation in Lebanon. ”
Many animals existed to provide blood food, including dinosaurs, flying reptiles called pterosaurs, other reptiles, birds, and mammals.
Researchers said that although these are the oldest fossils, mosquitoes likely originated millions of years ago. They noted that there is molecular evidence to suggest that mosquitoes arose during the Jurassic period, which lasted from about 200 million to 145 million years ago.
There are more than 3,500 species of mosquitoes worldwide and they can be found everywhere except Antarctica. Some become vectors for malaria, yellow fever, Zika, dengue, and other diseases. According to the World Health Organization, more than 400,000 people die each year from malaria, a parasitic infection, mostly children under the age of five.
“On the other hand, mosquitoes help purify water in ponds, lakes and rivers,” Nel says. “In general, animals can be a problem, but they can also be a help.”
Reporting: Will Dunham; Editing: Rosalba O’Brien
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