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Today, a groundbreaking study published in Nature reveals a pivotal discovery in understanding what fuels mosquitoes’ insatiable thirst for blood: their hormones. Researchers have identified a dual-hormone mechanism that either activates or suppresses mosquitoes’ cravings for blood, shedding light on a long-standing mystery.
“This discovery could potentially lead to new pesticide targets aimed at disrupting mosquito reproduction and curbing disease transmission,” explains Zhen Zou, an entomologist at the Chinese Academy of Science’s Institute of Zoology in Beijing.
Female mosquitoes of numerous species, including the notorious carrier Aedes aegypti responsible for diseases like dengue fever, yellow fever, and Zika, rely on blood meals to nourish their developing eggs. However, once they have fed, their attraction to blood diminishes until they have completed the egg-laying process.
Michael Strand, an entomologist from the University of Georgia, spearheaded the investigation into the hormonal control of this cycle. His team observed that levels of a hormone called neuropeptide F (NPF), produced in the mosquito’s gut, surged when the insect sought a host but rapidly declined post-blood meal.
“This hormonal fluctuation prompted us to explore whether NPF plays a pivotal role in driving their quest for blood,” says Strand.
The researchers meticulously studied mosquito enteroendocrine cells responsible for hormone production in the gastrointestinal tract. Their findings revealed a significant correlation: heightened NPF levels preceded a mosquito’s blood meal-seeking behavior, while its absence coincided with a loss of interest post-feeding.
In experimental trials where the gene responsible for NPF production was suppressed in female mosquitoes, their attraction towards human hosts notably decreased. Conversely, administering NPF to these genetically altered mosquitoes reinstated their interest in human hosts, albeit with little effect on mosquitoes already carrying eggs.
Furthermore, the study highlighted the role of another hormone, RYamide, also produced by neurons reaching into the gut. Following a blood meal, RYamide levels surged, inversely affecting NPF levels and suppressing host attraction in mosquitoes without eggs. This dual-hormone system, involving both NPF and RYamide, appears crucial in modulating mosquitoes’ feeding behavior.
Strand and his team aim to delve deeper into other molecular factors influencing host attraction, recognizing the complexities inherent in mosquito biology. “Life is never simple,” remarks Strand, underscoring the ongoing quest to unravel further nuances in mosquito behavior.
This study not only elucidates fundamental aspects of mosquito biology but also holds promise for developing targeted strategies to mitigate mosquito-borne diseases, potentially altering the landscape of public health interventions.
DOI: https://doi.org/10.1038/d41586-024-02126-w
