A research paper published in Nature on February 26, 2026, used some interesting genetic studies to support the idea that mosquitoes in Southeast Asia evolved a taste for human blood (anthropophily) at the time that the first hominins reached the area (Homo erectus). It is an interesting paper as it used data from the study of insects to confirm some ancient anthropological dates.
These are the details of this recent paper published in Nature on Feb. 26, 2026: Singh, U.S., Harbach, R.E., Hii, J. et al. Early hominin arrival in Southeast Asia triggered the evolution of major human malaria vectors. Sci Rep 16, 6973 (2026). https://doi.org/10.1038/s41598-026-35456-y
In the abstract, it mentions that some species belonging to a group called Leucosphyrus, part of the Anopheles mosquitoes that live in Southeast Asia not only transmit malaria, they are also fine tuned to drinking human blood. Other mosquitoes in the region occupy different niches, feeding off other monkeys (non-human primates or NHP) and transmit NHP malaria variants. This study analyzed the genes of mosquitoes from 11 species (including their mtDNA) and built dated phylogenetic trees for them.
The paper found that the original, basal species of mosquitoes in this region were monkey-feeding ones, living in what is now Malaysia, Borneo, and the Indonesian islands of Java and Sumatra, when this area was linked by a now submerged continental shelf, into Sundaland. During that time (Pliocene) the area was covered by a lush rainforest. The authors believe that "anthropophily most likely evolved once, involving adaptive introgression, in the early Pleistocene in Sundaland, giving rise to multiple descendent anthropophilic species. Such early origination of anthropophily must necessarily have been in response to the arrival of early hominins (Homo erectus) rather than anatomically modern humans, likely associated with loss and fragmentation of rainforests during the early Pleistocene. The early origination of anthropophily also provides independent non-archaeological evidence supporting the limited fossil record of early hominin colonization in Southeast Asia around 1.8 Mya." This date is roughly when Homo erectus reached the area.
The article reveals that mosquitoes are host-specific and that many genes are involved in this specificity. So "multiple genetic changes at these and other genes are required for the evolution of anthropophily, i.e. a strong, evolved preference for human blood. It is not surprising therefore that anthropophily is uncommon amongst the ~ 3500 known mosquito species. It is therefore more parsimonious to consider that anthropophily within a taxon has a single origin. Accordingly, it is improbable that there were multiple independent switches to anthropophily in the human-preferring species of the Dirus and Balabacensis Clades, which diverged around 1.3–0.5 Mya. Even taking into account some uncertainty in the molecular clock used for these divergence estimates these clades far predate the arrival of anatomically modern humans in SE Asia 76,000–63,000 years ago. We therefore reject with confidence the hypothesis that anthropophily in the Leucosphyrus Subgroup evolved in response to the arrival of modern humans in SE Asia."
Therefore it was an ancient event, long before human beings appeared in Africa.
The article adds that "Using the same molecular clock rate as applied in this study and a species tree, anthropophily would be inferred to have evolved ~ 509,000–61,000 years ago in the lineage leading to the major African malaria vectors, An. gambiae and An. coluzzii... Since An. gambiae originates in West African forests the switch to anthropophilly may instead have occurred in response to modern humans entering this forested region ~ 150,000 years ago. The emergence of anthropophily in the domestic form of Aedes aegypti and the molestus ecotype of Culex pipiens, both date to within the last 10,000 years, apparently in response to growing human populations and environmental change." So, the African human-feeding mosquitoes took place independently, and later than the SE Asian event(
Finally, the article "indicates that anthropophily in the Leucosphyrus Subgroup emerged much earlier than in other anthropophilic mosquito species. If a strictly bifurcating tree were assumed, anthropophily could have evolved either: by the time of node N1 [95% CI: 2.9–1.8 Mya] and subsequently been lost in the lineage leading to An. nemophilous and An. introlatus; or evolved twice along the lineages leading to the Dirus Clade (N3, 1.6 Mya [95% CI: 2.0–1.2 Mya]) and the Balabacensis Clade (N5, 0.5 Mya [95% CI: 0.7–0.4 Mya]).... We therefore consider the most parsimonious argument for the evolution of anthropophily in the Leucosphyrus Subgroup to be that it evolved once only through the process of adaptive introgression at nodes N1/N2 as this accommodates the multiplicity of genes underlying the trait and negates any need to invoke loss of this trait. According to this hypothesis, anthropophily would have evolved between the extremes of the N1 and N2 confidence intervals i.e. between 2.9 and 1.6 mya (Fig. 3) when all the lineages were in Sundaland, and prior to the divergence of the Dirus Clade (node N3, 1.6 Mya [95% CI: 2.0–1.2 Mya]) further north in Indochina. This hypothesis could be tested against the above alternatives by identifying the genes underlying anthropophily and characterizing their evolutionary history."
The interesting part in the preceding text is that dates, which on the "older" tip of the scale reach 2.9 and 2 million years back. This is in line with the recent findings in Eurasia about an early Homo erectus dispersal across Asia.
The authors continue (highlight is mine): "Dating of the evolution of anthropophily in the Leucosphyrus Group to 2.9–1.6 mya overlaps with the earliest proposed date for the arrival of early hominins (Homo erectus) into Sundaland at 1.8 Mya, but not with the more recent proposed date of 1.3 Mya. 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. This supports the hypothesis of Husson et al. that early hominins were present and abundant in Sundaland ~ 1.8 Mya, 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 SE Asia our findings contribute an important piece of evidence to the broader puzzle of the colonization of hominins in insular Southeast Asia".
Closing Comments
These findings add up to the other evidence mentioned in recent posts, suggesting a very early out of Africa (or even an Eurasian origin of hominins!). I have tried to learn more about American mosquitoes that feed on humans, but research seems to be scarce in this area other than focusing on the main vectors of malaria, dengue, yellow fever, Zika, and chikungunya (see this 2022 paper as an example). If there are anthropophilic mosiquitoes in America that could be dated, what dates would they provide? (several strains reached America after the European discovery, from Africa and Eurasia, the Aedes aegypti vector of yellow fever and Zika) originated in Africa and arrived with the slave trade, and Aedes albopictus, the "Asian tiger mosquito" arrived 40 years ago, from Asia, in used tires! Would other local strains shed light on the date of the peopling of America?
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