In a groundbreaking study reported in Current Biology, researchers have found the earliest-known fossil mosquitoes in Lebanese amber, revealing that ancient male mosquitoes likely fed on blood. Credit: Current Biology/Azar et al.
Researchers have unearthed the oldest fossil mosquitoes in Lebanese amber, showing that ancient male mosquitoes were likely blood-feeders. This finding from the Lower CretaceousThe Cretaceous is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era. It ended with the Cretaceous–Paleogene extinction event.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Cretaceous period sheds new light on the evolution of mosquitoes and their relationship with flowering plants.
Researchers reporting in the journal Current BiologyCurrent Biology is a peer-reviewed scientific journal published biweekly by Cell Press. It is focused on all aspects of biology, from molecular biology and genetics to ecology and evolutionary biology. The journal covers a wide range of topics, including cellular biology, neuroscience, animal behavior, plant biology, and more. Current Biology is known for its high-impact research articles, as well as its insightful commentary, analysis, and reviews of the latest developments in the field. It is widely read by scientists and researchers in biology and related fields, and has a reputation for publishing groundbreaking research that advances our understanding of the natural world.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Current Biology on December 4 have found the earliest-known fossil mosquito in Lower Cretaceous amber from Lebanon. What’s more, the well-preserved insects are two males of the same speciesA species is a group of living organisms that share a set of common characteristics and are able to breed and produce fertile offspring. The concept of a species is important in biology as it is used to classify and organize the diversity of life. There are different ways to define a species, but the most widely accepted one is the biological species concept, which defines a species as a group of organisms that can interbreed and produce viable offspring in nature. This definition is widely used in evolutionary biology and ecology to identify and classify living organisms.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>species with piercing mouthparts, suggesting they likely sucked blood. That’s noteworthy because, among modern-day mosquitoes, only females are hematophagous, meaning that they use piercing mouthparts to feed on the blood of people and other animals.
“Lebanese amber is, to date, the oldest amber with intensive biological inclusions, and it is a very important material as its formation is contemporaneous with the appearance and beginning of radiation of flowering plants, with all that follows of co-evolution between pollinators and flowering plants,” says Dany Azar of the Nanjing Institute of Geology and Palaeontology at the Chinese Academy of Sciences and the Lebanese University.
Mosquito in amber. Credit: Dany Azar
A New Perspective on Mosquito Evolution
“Molecular dating suggested that the family Culicidae arose during the JurassicThe Jurassic period is a geologic time period and system that spanned 56 million years from the end of the Triassic Period about 201.3 million years ago to the beginning of the Cretaceous Period 145 million years ago. It constitutes the middle period of the Mesozoic Era and is divided into three epochs: Early, Middle, and Late. The name "Jurassic" was given to the period by geologists in the early 19th century based on the rock formations found in the Jura Mountains, which were formed during the Jurassic period.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Jurassic, but previously the oldest record was mid-Cretaceous,” says André Nel of the National Museum of Natural History of Paris (Muséum National d’Histoire Naturelle de Paris). “Here we have one from the early Cretaceous, about 30 million years before.”
The Culicidae family of arthropods includes more than 3,000 species of mosquitoes. The new findings suggest that male mosquitoes in the past fed on blood as well, according to the researchers. They also help to narrow the “ghost-lineage gap” for mosquitoes, they say.
Implications and Future Research
Female mosquitoes are notorious for their blood-feeding ways, which has made them a major vector for spreading infectious diseases. Hematophagy in insects is thought to have arisen as a shift from piercing-sucking mouthparts used to extract plant fluids. For example, blood-sucking fleas likely arose from nectar-feeding insects. But the evolution of blood feeding has been hard to study in part due to gaps in the insect fossil record.
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Head, ventral view; scale bar 100 mm Credit: Current Biology/Azar et al.
In the new study, Azar, Nel, Diying Huang, and Michael S. Engel describe two male mosquitoes with piercing mouthparts, including an exceptionally sharp, triangular mandible and elongated structure with small, tooth-like denticles.
They report that the mosquitoes’ preservation in amber extends the definitive occurrence of the mosquito family of insects into the early Cretaceous. It also suggests that the evolution of hematophagy was more complicated than had been suspected, with hematophagous males in the distant past.
In future work, Nel says the team wants to learn more about the “utility” of having hematophagy in Cretaceous male mosquitoes. They’re also curious to explore “why this no longer exists,” he says.
Reference: “The earliest fossil mosquito” by Dany Azar, André Nel, Diying Huang and Michael S. Engel, 4 December 2023, Current Biology.
DOI: 10.1016/j.cub.2023.10.047
Funding: National Natural Science Foundation of China
Source: SciTechDaily
