130-million-year-old fossils of mosquitoes reveal a bloodsucking surprise

The fossils, discovered near Hammana in Lebanon, date back to the Cretaceous Period, an era when dinosaurs roamed the Earth.

In Short

• This anatomical feature was previously thought to be exclusive to females
• Prehistoric mosquitoes likely evolved from non-blood-consuming insects
• Mosquitoes are notorious for transmitting diseases

Scientists have unearthed the oldest-known mosquito fossils, revealing that both male and female mosquitoes were once blood-feeders.

The study, published in the journal Current Biology, details the findings of two male mosquito fossils from 130 million years ago, challenging the current understanding that only female mosquitoes feed on blood.

The fossils, discovered near Hammana in Lebanon, date back to the Cretaceous Period, an era when dinosaurs roamed the Earth. These ancient mosquitoes, preserved in amber, exhibit elongated mouthparts akin to those used by modern female mosquitoes for drawing blood.

This anatomical feature, previously thought to be exclusive to females, suggests that hematophagy — the consumption of blood — was a trait shared by both sexes in the past.

Palaeontologist Dany Azar of the Chinese Academy of Sciences' Nanjing Institute of Geology and Paleontology and Lebanese University, who led the research, expressed astonishment at the findings. "Clearly they were hematophagous," Azar stated, emphasising the significance of this discovery in understanding mosquito evolution.

The study co-authored by Andre Nel of the National Museum of Natural History of Paris, indicates that these prehistoric mosquitoes likely evolved from non-blood-consuming insects.

The shift to blood-feeding may have been a transition from piercing plants for their fluids to exploiting the rich protein source found in the blood of vertebrates.

The emergence of flowering plants during the Cretaceous might have influenced the dietary divergence between male and female mosquitoes, with males eventually losing the blood-feeding behavior.

The researchers hypothesise that the availability of nectar from these new plant species provided an alternative food source, leading to the current-day scenario where only fertilized female mosquitoes seek blood meals to nourish their developing eggs.

While mosquitoes are notorious for transmitting diseases such as malaria, yellow fever, and Zika, causing over 4,00,000 deaths annually, mostly among children under five, according to the World Health Organization, they also play a beneficial role in ecosystems.

As Nel points out, mosquitoes contribute to water purification in aquatic environments.

With over 3,500 species of mosquitoes now inhabiting the planet, save for Antarctica, the study offers a glimpse into the ancient past of these pervasive creatures that continue to impact human health and biodiversity worldwide.

Published By:
Sibu Kumar Tripathi
Published On:
Dec 6, 2023