Ancient Mosquito Fossil Unveils a Bloodsucking Surprise, Rewriting History

Researchers have made a surprising discovery with the identification of the oldest-known fossils of mosquitoes, dating back to 130 million years ago during the Cretaceous Period. Two male mosquitoes were found preserved in amber near the town of Hammana in Lebanon.

An undated handout image of a view from below of the head of a fossilized male mosquito

What makes this finding remarkable is that these male mosquitoes had elongated piercing-sucking mouthparts, a feature currently seen only in females. The fossils provide insights into the evolution of mosquitoes and their specialized mouth anatomy, shedding light on their history dating back to the age of dinosaurs.

Paleontologist Dany Azar, the lead author of the study published in the journal Current Biology, explained that the two fossilized mosquitoes, dating back to 130 million years ago, were clearly hematophagous, meaning blood-eaters. This discovery is significant in the evolutionary history of mosquitoes, shedding light on their ancient origins.

Despite their resemblance in size and appearance to modern mosquitoes, these ancient specimens exhibit shorter mouthparts used for obtaining blood compared to today's female mosquitoes. The findings provide valuable insights into the early adaptations and evolution of mosquitoes, marking a crucial discovery in understanding their role in ecosystems and the transmission of diseases over millions of years.

Dany Azar highlighted the significance of mosquitoes as notorious blood-feeders on humans and other terrestrial vertebrates. Mosquitoes play a crucial role in transmitting parasites and diseases to their hosts. Azar explained that only fertilized female mosquitoes engage in blood-feeding as they require proteins for the development of their eggs.

In contrast, males and unfertilized females typically feed on nectar from plants, and some males may not feed at all. Understanding the feeding behaviors and evolutionary history of mosquitoes provides valuable insights into their ecological roles and the potential transmission of diseases over time.

While certain flying insects, such as tsetse flies, have hematophagous males, this behavior is not observed in modern mosquitoes. The discovery of hematophagous male mosquitoes in the Cretaceous Period is surprising and offers new insights into the evolutionary history of these insects, according to André Nel, a paleontologist and co-author of the study.

The exquisitely preserved fossils reveal remarkably sharp, triangle-shaped jaw anatomy and an elongated structure with tooth-like projections in both mosquitoes. The researchers propose that mosquitoes evolved from insects that did not feed on blood and that the mouthparts adapted for blood meals were originally used to pierce plants for accessing nutritious fluids.

The researchers hypothesize that the feeding divergence between male and female mosquitoes may be linked to plant evolution. During the Cretaceous Period, when these mosquitoes were trapped in amber, flowering plants were emerging, potentially influencing the evolution of mosquito feeding habits from plant liquid sucking to bloodsucking.

The discovery that the earliest-known mosquitoes were bloodsucking males suggests that the original mosquitoes were all hematophagous, regardless of gender. The adaptation of hematophagy was later lost in males, potentially due to the emergence of flowering plants, which coincided with the formation of Lebanese amber, where the fossils were found. The researchers note that there were abundant animals, including dinosaurs, pterosaurs, reptiles, birds, and mammals, to provide blood meals during this time.

While these fossils represent the oldest-known mosquitoes, molecular evidence suggests that mosquitoes likely originated millions of years earlier, possibly during the Jurassic Period. Today, there are more than 3,500 species of mosquitoes worldwide, playing diverse roles in ecosystems. While some mosquitoes transmit diseases, others contribute to water purification in ponds, lakes, and rivers. Understanding the evolutionary history of mosquitoes provides valuable insights into their ecological roles and interactions with other organisms.