Recent studies reveal that the ancestors of today’s malaria-spreading mosquitoes belong to the Anopheles leukophilus (Leucosphyrus) group. These mosquitoes may have begun feeding on humans approximately 1.8 million years ago, coinciding with the arrival of Homo erectus in Southeast Asia.
The arrival of Homo erectus led to the evolution of the primary human malaria vector in Southeast Asia 1.8 million years ago.
Feeding on humans is relatively rare among the 3,500 known species of mosquitoes; however, this predation behavior is a critical factor that enhances the likelihood of mosquitoes transmitting disease-causing pathogens.
“Mosquito-borne diseases represent a significant threat to public health,” stated study lead author Upasana Shamsunder Singh and her colleagues.
“The tendency of certain mosquito species to prefer humans (anthropism) significantly influences their capacity to transmit disease-causing pathogens.”
“While mosquitoes can show versatility in host selection, understanding the evolutionary roots of anthropogenicity and the circumstances that led to its development can offer valuable insights for combatting emerging diseases linked to mosquito-borne pathogens.”
For this study, researchers sequenced the DNA of 38 mosquitoes across 11 species from the genus Leucosphyllus collected in Southeast Asia between 1992 and 2020.
These DNA sequences, in conjunction with computer models and mutation rate estimates, allowed the team to reconstruct the evolutionary history of these mosquito species.
The researchers estimate that the preference for feeding on humans evolved within Leucosphyllus just once, between 2.9 million and 1.6 million years ago, in the Sundaland region, which includes the Malay Peninsula, Borneo, Sumatra, and Java.
Before this shift, the ancestors of the Leucosphyllus mosquito primarily fed on non-human primates.
This timeline aligns with the earliest proposed arrival of Homo erectus in the area around 1.8 million years ago, well before modern humans appeared approximately 76,000 to 63,000 years ago.
These findings also predate earlier estimates regarding the evolution of human-feeding preferences in the mosquito lineage that gave rise to Africa’s principal malaria vectors, such as Anopheles gambiae and Anopheles mosquito, which evolved between 509,000 and 61,000 years ago.
Prior studies indicate that shifts in mosquito dietary preferences necessitate multiple genetic changes related to the receptors that detect body odor.
The researchers suggest that the evolution of preferences for human body odors in Leucosphyllus may have been crucial due to the sizable populations of Homo erectus in Sundaland around 1.8 million years ago.
“Our findings imply that the anthropophilic Leucosphyllus group emerged in Sundaland during the Early Pleistocene. They must have been well-established and numerous in this region to adapt to preferences for human hosts,” the researchers noted.
“This supports the hypothesis that early hominins were both present and abundant in Sundaland 1.8 million years ago, before migrating through land bridges to Java.”
Middle Pleistocene fossils of Homo erectus suggest long-term habitation of the exposed Sundaland landmass, potentially linked to large river systems.
“Given the highly fragmented fossil record in tropical Southeast Asia, our findings provide crucial evidence for understanding hominin colonization in this region,” added the research team.
The team’s findings were published in the journal Scientific Reports.
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US Thin others. 2026. The arrival of early humans in Southeast Asia led to the evolution of a major human malaria vector. Scientific Reports 16, 6973; doi: 10.1038/s41598-026-35456-y
Source: www.sci.news
