Discovered in Lebanon, Oldest Mosquito Fossil Comes with a Bloodsucking Surprise

 An undated handout image of a view from above of the body of a fossilized male mosquito trapped in amber found in central Lebanon dating to about 130 million years ago. (Dany Azar/Handout via Reuters)
An undated handout image of a view from above of the body of a fossilized male mosquito trapped in amber found in central Lebanon dating to about 130 million years ago. (Dany Azar/Handout via Reuters)
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Discovered in Lebanon, Oldest Mosquito Fossil Comes with a Bloodsucking Surprise

 An undated handout image of a view from above of the body of a fossilized male mosquito trapped in amber found in central Lebanon dating to about 130 million years ago. (Dany Azar/Handout via Reuters)
An undated handout image of a view from above of the body of a fossilized male mosquito trapped in amber found in central Lebanon dating to about 130 million years ago. (Dany Azar/Handout via Reuters)

Hundreds of thousands of people worldwide are killed annually by malaria and other diseases spread through the bite of mosquitoes, insects that date back to the age of dinosaurs. All of these bites are inflicted by females, which possess specialized mouth anatomy that their male counterparts lack.

But it has not always been that way. Researchers said they have discovered the oldest-known fossils of mosquitoes - two males entombed in pieces of amber dating to 130 million years ago during the Cretaceous Period and found near the town of Hammana in Lebanon. To their surprise, the male mosquitoes possessed elongated piercing-sucking mouthparts seen now only in females.

"Clearly they were hematophagous," meaning blood-eaters, said paleontologist Dany Azar of the Chinese Academy of Sciences' Nanjing Institute of Geology and Paleontology and Lebanese University, lead author of the study published this week in the journal Current Biology. "So this discovery is a major one in the evolutionary history of mosquitoes."

The two fossilized mosquitoes, both representing the same extinct species, are similar in size and appearance to modern mosquitoes, though the mouthparts used for obtaining blood are shorter than in today's female mosquitoes.

"Mosquitoes are the most notorious blood-feeders on humans and most terrestrial vertebrates, and they transmit a certain number of parasites and diseases to their hosts," Azar said.

"Only fertilized female mosquitoes will suck blood, because they need proteins to make their eggs develop. Males and unfertilized females will eat some nectar from plants. And some males do not feed at all," Azar added.

Some flying insects - tsetse flies, for instance - have hematophagous males. But not modern mosquitoes.

"Finding this behavior in the Cretaceous is quite surprising," said paleontologist and study co-author André Nel of the National Museum of Natural History of Paris.

The delicate anatomy of the two mosquitoes was beautifully preserved in the fossils. Both displayed exceptionally sharp and triangle-shaped jaw anatomy and an elongated structure with tooth-like projections.

The researchers said they suspect that mosquitoes evolved from insects that did not consume blood. They hypothesize that the mouthparts that became adapted for obtaining blood meals originally were used to pierce plants to get access to nutritious fluids.

Plant evolution may have played a role in the feeding divergence between male and female mosquitoes. At the time when these two mosquitoes became stuck in tree sap that eventually became amber, flowering plants were beginning to flourish for the first time on the Cretaceous landscape.

"In all hematophagous insects, we believe that hematophagy was a shift from plant liquid sucking to bloodsucking," Azar said.

The fact that these earliest-known mosquitoes are bloodsucking males, Azar added, "means that originally the first mosquitoes were all hematophagous - no matter whether they were males or females - and hematophagy was later lost in males, maybe due to the appearance of flowering plants, which are contemporaneous with the formation of Lebanese amber."

Plenty of animals were present to provide blood meals: dinosaurs, flying reptiles called pterosaurs, other reptiles, birds and mammals.

The researchers said while these are the oldest fossils, mosquitoes probably originated millions of years earlier. They noted that molecular evidence suggests mosquitoes arose during the Jurassic Period, which ran from about 200 million to 145 million years ago.

There are more than 3,500 species of mosquitoes worldwide, found everywhere except Antarctica. Some become disease vectors transmitting malaria, yellow fever, Zika fever, dengue and other diseases. According to the World Health Organization, more than 400,000 people die annually from malaria - a parasitic infection - mostly children under age 5.

"On the other side, mosquitoes help to purify the water in ponds, lakes and rivers," Nel said. "In general, an animal can be a problem but also can be helpful."



Researchers Document Huge Drop in African Elephants in a Half Century

 Elephants walk at the Amboseli National Park in Kajiado County, Kenya, April 4, 2024. REUTERS/Monicah Mwangi/File Photo
Elephants walk at the Amboseli National Park in Kajiado County, Kenya, April 4, 2024. REUTERS/Monicah Mwangi/File Photo
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Researchers Document Huge Drop in African Elephants in a Half Century

 Elephants walk at the Amboseli National Park in Kajiado County, Kenya, April 4, 2024. REUTERS/Monicah Mwangi/File Photo
Elephants walk at the Amboseli National Park in Kajiado County, Kenya, April 4, 2024. REUTERS/Monicah Mwangi/File Photo

African elephants are Earth's largest land animals, remarkable mammals that are very intelligent and highly social. They also are in peril. Fresh evidence of this comes in a study that documents alarming population declines at numerous sites across the continent over about a half century.

Researchers unveiled on Monday what they called the most comprehensive assessment of the status of the two African elephant species - the savanna elephant and forest elephant - using data on population surveys conducted at 475 sites in 37 countries from 1964 through 2016.

The savanna elephant populations fell by about 70% on average at the surveyed sites and the forest elephant populations dropped by about 90% on average at the surveyed sites, with poaching and habitat loss the main drivers. All told, there was a 77% population decrease on average at the various surveyed sites, spanning both species, Reuters reported.

Elephants vanished at some sites while their populations increased in other places thanks to conservation efforts.

"A lot of the lost populations won't come back, and many low-density populations face continued pressures. We likely will lose more populations going forward," said George Wittemyer, a Colorado State University professor of wildlife conservation and chair of the scientific board of the conservation group Save the Elephants, who helped lead the study published in the journal Proceedings of the National Academy of Sciences.

Poaching typically involves people killing elephants for their tusks, which are sold illegally on an international black market driven mostly by ivory demand in China and other parts of Asia. Agricultural expansion is the top factor in habitat loss.

The forest elephant population is estimated to be about a third that of savanna elephants. Poaching has affected forest elephants disproportionately and has ravaged populations of both species in northern and eastern Africa.

"We have lost a number of elephant populations across many countries, but the northern Sahel region of Africa - for example in Mali, Chad and Nigeria - has been particularly hard hit. High pressure and limited protection have culminated in populations being extirpated," Wittemyer said.

But in southern Africa, elephant populations rose at 42% of the surveyed sites.

"We have seen real success in a number of places across Africa, but particularly in southern Africa, with strong growth in populations in Botswana, Zimbabwe and Namibia. For populations showing positive trends, we have had active stewardship and management by the governments or outside groups that have taken on a management role," Wittemyer said.

The study did not track a continent-wide population tally because the various surveys employed different methodologies over different time frames to estimate local elephant population density, making a unified head count impossible. Instead, it assessed population trends at each of the surveyed sites.

A population estimate by conservationists conducted separately from this study put the two species combined at between 415,000 and 540,000 elephants as of 2016, the last year of the study period. It remains the most recent comprehensive continent-wide estimate.

"The loss of large mammals is a significant ecological issue for Africa and the planet," said conservation ecologist and study co-author Dave Balfour, a research associate in the Centre for African Conservation Ecology at Nelson Mandela University in South Africa.

The world's third extant elephant species, the slightly smaller Asian elephant, faces its own population crisis, with similar factors at play as in Africa.

Of African elephants, Wittemyer said, "While the trends are not good, it is important to recognize the successes we have had and continue to have. Learning how and where we can be successful in conserving elephants is as important as recognizing the severity of the decline they have experienced."

Wittemyer added of these elephants: "Not only one of the most sentient and intelligent species we share the planet with, but also an incredibly important part of ecosystems in Africa that structures the balance between forest and grasslands, serves as a critical disperser of seeds, and is a species on which a multitude of other species depend on for survival."