These hormones stimulate the mosquito’s desire for blood.
Scientists say mosquitoes have two hormones: one that stimulates their blood craving and one that tells them they’re full.
Joao Paulo Brini/Getty Images
A pair of hormones work together to activate or inhibit Mosquito blood cravingsAccording to a study published today.
The results of this study are: Mosquitoes are attracted to humans “This discovery could potentially provide new insecticide targets to prevent mosquito breeding and disease transmission,” said Zhen Zou, an entomologist at the Institute of Zoology, Chinese Academy of Sciences in Beijing.
The females of most mosquito species Aedes aegypticarriers of the causative virus Dengue feverMosquitoes, which transmit infectious diseases such as rabies, yellow fever, and Zika, feed on the blood of animals to develop their eggs, but once they have had a blood meal, they no longer have a desire for blood until they are ready to lay eggs.
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Entomologist Michael Strand of the University of Georgia in Athens wanted to better understand the mechanisms that control this attraction cycle. He noticed that concentrations of a hormone called neuropeptide F (NPF), produced in the insect’s gut, spike when the mosquito is searching for a host and disappear after it has eaten blood. “That prompted us to ask whether the presence of this hormone drives blood seeking,” Strand says.
Strand and his colleagues analyzed mosquito enteroendocrine cells, which produce the hormone in their digestive tracts. As expected, NPF levels spiked before the mosquito took a blood meal and then dropped six hours after. The mosquitoes’ attraction to humans also matched this hormone fluctuation: they showed no interest in human hands on the day of their blood meal, but made a beeline for them after laying their eggs. “We saw an almost perfect mirror image,” Strand says.
Next, the researchers knocked down the gene that produces NPF in female mosquitoes and found that it made them less attractive to humans. Injecting the hormone into the mutant mosquitoes restored their interest in humans but had little effect on the mosquitoes carrying eggs.
The team also found that certain neurons reaching the gut produce another hormone called RYamide, which controls the insect’s feeding behavior. RYamide levels increased just as NPF levels decreased after a blood meal. Injecting egg-free mosquitoes with RYamide reduced NPF levels and inhibited attraction to human hosts, while control mosquitoes (with natural hormone levels) flew away toward the human hand. This suggests that NPF and RYamide work together to stimulate or inhibit mosquito host attraction.
Strand and his colleagues plan to investigate other molecular factors involved in host attraction to build a more complete picture. “Life is never simple,” he says.
This article is reprinted with permission. First Edition July 1, 2024.
