The ancestors of today’s malaria-spreading mosquitoes in the Anopheles leucosphyrus (Leucosphyrus) group may have shifted to feeding on humans around 1.8 million years ago, coinciding with the arrival of Homo erectus in Southeast Asia.
The arrival of Homo erectus in Southeast Asia 1.8 million years ago triggered the evolution of major human malaria vectors.
A preference for feeding on humans is uncommon among the 3,500 known mosquito species, yet this feeding preference is the main factor influencing the potential of mosquitoes to spread disease-causing pathogens.
“Mosquito-borne diseases present a significant burden on human health,” said study’s lead author Upasana Shyamsunder Singh and colleagues.
“The propensity of mosquitoes of a particular species to feed on humans (anthropophily) is the primary factor influencing their potential to spread pathogens that cause disease.”
“Although mosquitoes can be opportunistic in their host selection (e.g many species display varying degrees of host specificity), understanding the evolutionary origins of anthropophily and the circumstances that triggered its development can provide critical insights into mitigating the impacts of novel diseases due to mosquito-borne pathogens.”
For their research, the authors sequenced the DNA of 38 mosquitoes from 11 species in the Leucosphyrus group, which were obtained between 1992 and 2020 from Southeast Asia.
They used these sequences, computer models, and estimates of DNA mutation rates to reconstruct the evolutionary history of these species.
They estimate that the preference for feeding on humans evolved once within Leucosphyrus between 2.9 and 1.6 million years ago in a region known as Sundaland, which includes the Malay Peninsula, Borneo, Sumatra, and Java.
Prior to this, ancestors of Leucosphyrus mosquitoes fed on non-human primates.
This overlaps with the earliest proposed date for the arrival of the hominin species Homo erectus in the region around 1.8 million years ago and predates the arrival of modern humans between 76,000 and 63,000 years ago.
It also predates previously published estimates of the evolution of a preference for feeding on humans among the mosquito lineage that gave rise to the major African malaria carriers Anopheles gambiae and Anopheles coluzzii between 509,00 and 61,000 years ago.
Previous research has suggested that changes in mosquito feeding preferences require multiple changes in genes that encode receptors used to detect body odor.
The researchers propose that the evolution of a preference for human body odor among Leucosphyrus may have required Homo erectus to be present in substantial numbers in Sundaland around 1.8 million years ago.
“Our findings suggest that anthropophily in the Leucosphyrus group emerged in Sundaland in the Early Pleistocene in response to the arrival of early hominins who must have not only been present in this region by this time but must have been in substantial numbers to drive adaptation to human host preference,” they said.
“This supports the hypothesis that early hominins were present and abundant in Sundaland 1.8 million years ago, prior to their dispersal via land bridges to Java.”
“Middle Pleistocene fossils of Homo erectus indicate their prolonged occupation on the exposed Sundaland landmass, likely associated with extensive river systems.”
“In the context of the very fragmentary nature of the fossil record in tropical Southeast Asia our findings contribute an important piece of evidence to the broader puzzle of the colonization of hominins in insular Southeast Asia.”
The team’s findings were published today in the journal Scientific Reports.
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U.S. Singh et al. 2026. Early hominin arrival in Southeast Asia triggered the evolution of major human malaria vectors. Sci Rep 16, 6973; doi: 10.1038/s41598-026-35456-y
