Two of the world’s deadliest mosquito vectors – Aedes aegypti and Anopheles funestus – have evolved, spread, and adapted in ways that complicate global disease control, two studies show. The findings trace the human-linked origins of Ae. aegypti’s invasive lineage. They also reveal the rapid emergence of insecticide resistance in An. funestus. Collectively, they reveal the urgent need for more tailored and innovative interventions against malaria and dengue. Top of Form“Both [studies] provide important insights into the … the complex role that human activity, both passive and intentional, plays in their movement and adaptations,” writes Tamar Carter in a related Perspective. “These processes have led to complex subspecies genomic diversity that likely translates to functional diversity that is yet to be fully elucidated.”Bottom of Form Mosquito vector-borne diseases represent a major global health challenge, with malaria and dengue each causing hundreds of millions of infections annually, worldwide. The increasing mobility of people and goods has enabled mosquitoes, once confined to relatively narrow regions, to spread widely and adapt to new environments. Although modern genomic analyses could provide insight into the origin, evolution, spread, and control of these vectors, individual mosquito species are unequally represented in studies. Here, in a pair of studies, researchers analyze genomic data from Ae. aegypti and An. funestus mosquitoes to reconstruct their evolutionary and demographic histories.

 

In one study, Jacob Crawford and colleagues investigated Ae. aegypti – the primary vector of dengue, chikungunya, and Zika. The precise origin of the globally invasive Ae. aegypti has long been debated. Crawford et al. sequenced 1206 genomes from 73 globally distributed populations, using coalescent and phylogenetic analyses to disentangle ancient from recent migration events. According to the findings, after evolving a preference for humans in West Africa, Ae. Aegypti made its way to the Americas during the Atlantic slave trade, with the globally invasive lineage ultimately arising in the Americas. More recently, this invasive lineage has re-entered Africa and interbred with native populations, coinciding with increased dengue outbreaks and the spread of insecticide-resistance mutations.

 

In another study, Marilou Boddé and colleagues performed a sweeping genomic analysis of An. funestus to investigate how this major malaria vector has adapted, particularly under vector control pressure. Boddé et al. sequenced 701 modern and historic An. Funestus mosquitoes from 16 African countries. The findings revealed a complex population structure – while some populations showed strong geographic structuring, others were genetically connected across wide distances, with distinct lineages emerging in places like North Ghana and South Benin. According to the authors, this diversity suggests that uniform control strategies are unlikely to succeed, emphasizing the need for locally tailored interventions. Moreover, by comparing modern samples with century-old museum specimens, the team showed that insecticide resistance arose both through independent mutations and the spread of resistant lineages. Most insecticide resistant variants found in modern An. Funestus were not found in historical species from as recent as 1967, suggesting rapid emergence. Boddé et al. also discovered promising gene drive targets within An. Funestus, which could enable more effective and strategic vector control efforts.

 

For reporters interested in trends, an August 2025 Science Translational Medicine study [https://www.science.org/doi/10.1126/scitranslmed.adq4326] by Quandelacy et al. provided an in-depth analysis of dengue transmission in the Americas, revealing regional outbreak patterns and how they are shaped by climatic factors.

Zebra finches can not only distinguish the full range of their species’ vocalizations but also organize them by meaning, according to a new study. The results suggest a surprising level of semantic understanding in the birds. Many social animals use a rich repertoire of vocalizations to communicate their needs, emotions, and awareness of the environment. Researchers have long tried to decode these sounds – essentially the species’ “language” – by grouping them into call types based on how they sound, the situations in which they are used, and how other animals respond. However, it is unclear whether these categories reflect the animals’ own perception or understanding of meaning. Zebra finches, highly social songbirds that use around 11 distinct call types for diverse social behaviors, offer a useful model to evaluate these questions. To test how adult zebra finches classify their species’ vocalizations, Julie Elie and colleagues performed an experiment involving 12 finches, in which the birds had to distinguish one rewarded call type from the other ten nonrewarded call types, including those from other, unfamiliar species. Elie et al. found that these birds have a remarkable ability to distinguish all call types in their vocal repertoire, demonstrating that they can accurately perceive and categorize their species’ vocal signals. Importantly, the authors found that call “misclassifications” were more common between call-types used in similar behavioral or social contexts, suggesting that zebra finches organize calls semantically and form mental representations of their underlying meanings.