Mosquito Day: What is the oldest mosquito? and other key facts

Today, August 20, is World Mosquito Day , and to mark the occasion, we're sharing three facts about this creature, which, according to the World Health Organization , is the world's deadliest animal .

When man appeared, the mosquito was already there , say some people who have written about the antiquity of this animal, paraphrasing the shortest story in the world: “ When he woke up, the dinosaur was still there,” by the Guatemalan Augusto Monterroso .

Indeed, 23 researchers, led byJohn Soghigian , published in 2023 in Nature that mosquitoes have existed for 217 million years and emerged in the Early Triassic in what was the supercontinent Gondwana , before separating, and is today South America .

Mosquitoes originated in the Triassic (217 million years ago) before the major diversifications of the dinosaur and mammal lineages into many different species, when the dominant vertebrates were crocodile-like reptiles called archosaurs , the researchers say.

The Triassic is the first of the three periods of the Mesozoic Era ; it is followed by the Jurassic and Cretaceous , when dinosaurs dominated and became extinct, respectively.

Soghigian 's scientific team conducted the largest phylogenetic study of mosquitoes, with samples collected on six continents, and created a genetic map of the mosquito family tree.

In contrast, the first hominid , Sahelanthropus tchadensis , lived 6-7 million years ago (in the Miocene , the fourth epoch of the Tertiary period of the current Cenozoic era); it is the oldest known fossil, found in the 1990s in Toros-Menalla in Chad , a country in central Africa , according to the book “The story of the origin of man” .

In turn, Homo sapiens , modern man, is around 300,000 years old, according to recent research in archaeology, paleoanthropology and genetics , reported the Spanish National Research Council (CSIIC) in 2024.

The oldest mosquito is Libanoculex intermedius , of which two fossils of male specimens were found preserved in amber from the Early Cretaceous (145-100.5 million years ago) in Lebanon dating back about 125-130 million years , four researchers from China, Lebanon, France and the United States, led by Dany Azar, reported in 2023 .

Azar specifies that Libanoculex intermediu is a new species of mosquito. Its taxonomy is as follows: Diptera (order), Nematocera (suborder), Culicidae (family), Libanoculicinae (subfamily), Libanoculex (genus) and Libanoculex intermedius (species).

The male Libanoculex intermediu has well-developed, denticulated, blood-sucking mouthparts, which “suggests that not only were early female mosquitoes blood-sucking, but that males were also blood-sucking in some cases,” the authors state.

They also say that Libanoculex intermediu belongs to the extinct subfamily Libanoculicinae , and compare them with their siblings from the also extinct subfamily Burmaculicinae , both belonging to the family Culicidae .

The researchers note that “all extant (and probably fossil) female midges ( Culicidae ) are hematophagous and nectarivorous , whereas extant species of their sister group, Chaoboridae, are nectar feeders.”

Chaoboridae is a small family of so-called ghost flies , with just one genus, Chaoborus , with 12 recorded species, says researcher William L. Hilsenhoff . “Adults are medium-sized, non-biting , live about a week, and lay several hundred eggs in rafts on the water’s surface.”

According to the Soghigian map, the mosquitoes Chaoboridae and Culicidae have a common ancestor that lived in the Triassic .

In the Jurassic , reports Soghigian , there lived the common ancestor of the culicids that fed on amphibians and, after the Cretaceous-Paleogene mass extinction , it began to feed on mammals and birds .

Today, Wednesday, World Mosquito Day has been commemorated in several countries for 128 years to remember that on August 20, 1897, the Indian doctor Ronald Ross, Nobel Prize winner in Physiology or Medicine in 1902 , discovered , by dissecting these insects, that mosquitoes transmit malaria from infected birds to healthy birds.

Sixteen years earlier, in 1881, the now also famous Cuban doctor Carlos J. Finlay Barrés discovered that the mosquito Stegomia fasciatus , now known as Aedes aegypti , transmitted yellow fever , a disease that caused mass flight of people to safety where it occurred because it was very lethal.

World Mosquito Day aims to educate people on the identification, monitoring, and control of mosquito populations to prevent diseases such as dengue, malaria, chikungunya, Zika, West Nile fever , and others.

On World Mosquito Day 2025 , the Wolbachia method , the name of the bacteria that reduces mosquitoes' ability to transmit viruses to people, is being disseminated, says the World Mosquito Programme .

This month there will be another anniversary related to mosquitoes: every August 26th is International Dengue Day .