Earliest-Known Fossil Mosquito Found in Lebanese Amber

Female mosquitoes are among the most notorious hematophagous (blood-feeding) insects, sometimes causing severe allergic responses. Hematophagy in insects is likely a feeding shift from plant fluids, with the piercing-sucking mouthparts serving as suitable exaptation for piercing vertebrates’ skin. The origins of these habits are mired in an often-poor fossil record for many hematophagous lineages, particularly those of sufficient age, as to give insights into the paleoecological context in which blood feeding first appeared or even to arrive at gross estimates as to when such shifts have occurred. This is certainly the case for mosquitoes, a group estimated molecularly to date back to the Jurassic period. Now, paleontologists have described a new species of mosquito found in 125-million-year-old amber from Lebanon. The males of the new species unexpectedly had piercing mouthparts, armed with sharp mandibles, and were likely hematophagous.

Mosquitoes are approximately 3,600 species of small flies comprising the family Culicidae.

All living — and likely fossil — female mosquitoes are hematophagous and nectarivorous, whereas living species of their sister group, Chaoboridae (phantom midges or glassworms), are nectar feeding.

Thus, a shift from strict nectarivory to partial hematophagy has occurred, but scientists still don’t know whether the earliest mosquitoes were hematophagous or not.

The discovery of two male mosquitoes with piercing mouthparts, preserved in amber from Lebanon, extends the definitive occurrence of the Culicidae family into the Early Cretaceous.

The new specimens represent a new species of mosquitoes, Libanoculex intermedius.

They also represent a new, now-extinct mosquito subfamily, Libanoculicinae.

“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 what follows of co-evolution between pollinators and flowering plants,” said Dr. Dany Azar, a paleontologist with the Nanjing Institute of Geology and Palaeontology at the Chinese Academy of Sciences and the Lebanese University.

“Molecular dating suggested that the family Culicidae arose during the Jurassic, but previously the oldest record was mid-Cretaceous,” added Dr. André Nel, a paleontologist with the National Museum of Natural History of Paris.

“Here, we have one from the Early Cretaceous, about 30 million years before.”

The new findings suggest that male mosquitoes in the past fed on blood as well.

They also help to narrow the ‘ghost-lineage gap’ for mosquitoes.

“Phylogenetic analysis indicates that the new fossil represents a lineage of mosquitoes that diverged earlier than the subfamily Burmaculicinae, narrowing the ghost-lineage gap for mosquitoes and providing glimpses into Mesozoic culicid paleodiversity,” the authors said.

“This discovery also suggests that not only were the earliest female mosquitoes hematophagous but males were also in some cases.”

“In future work, we want to learn more about the utility of having hematophagy in Cretaceous male mosquitoes,” Dr. Nel said.

“They’re also curious to explore why this no longer exists.”

The study appears today in the journal Current Biology.

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Dany Azar et al. 2023. The earliest fossil mosquito. Current Biology 33 (23): 5240-5246; doi: 10.1016/j.cub.2023.10.047