Certain mosquitoes like taste of flowers
When blood and syrupy nectar are both on the menu, pitcher plant mosquitoes tend to go for the vegetarian option. But not all of them do. A new Ohio State study uses the species’ dietary variety to explore why those mosquitoes, whose scientific name is
have evolved from their ancestor’s blood-based regimen to one that favors blossom-based meals.
To demonstrate the species’ evolutionary transformation, researchers genetically compared populations from Maine and Florida, where pitcher flower mosquitoes are split in their taste for blood over flowers.
“Mother Nature has a nice experiment going out there. What makes one population biters and another vegetarian?” said David Denlinger, Ohio State professor emeritus of entomology and co-author of the study published in the November issue of the journal Proceedings of the National Academy of Sciences. “What we saw were several rather striking differences.”
The scientists at Ohio State and the University of Oregon found that the mostly flowerfavoring mosquitoes have evolved over time from a reliance on blood.
The blood-lusting mosquitoes studied still had genes associated with smelling and protein disintegration necessary to seek out and digest blood meals.
The mosquitoes evolved toward vegetarianism because of the drawbacks of depending on protein-rich blood for nourishment, Denlinger said.
For one, the warm meal puts stress on the mosquito’s body, zaps the bug’s energy level and can contain toxic compounds.
Plus, blood-feeding saddles the mosquitoes with a glut of blood in the gut, which makes it hard to fly — and even harder to dodge predators or swatting hands.
“It’s a risky endeavor,” Denlinger said. “There are all kinds of perils out there.” Researchers focused on
in the study because the entire species shares a common genetic background but shows regional dietary differences.
However, the species is
not an important carrier of diseases like malaria, West Nile, Zika or dengue, a deadly disease that threatens a third of Earth’s human population, according to the study.
But if scientists can unpack what triggers the genetic transformation from blood to flower feeding, they might be able to learn how to manipulate that mechanism.
In the case of blood-borne pathogens spread by mosquitoes, the idea is simple: no bite, no disease transmission.
“What lies ahead is the challenge of ‘What is it that could switch off that behavior?’” Denlinger said. “That would be a whole new
avenue that could perhaps be exploited for insect control.”
In Ohio, the northern house mosquito and the Asian tiger mosquito are among the most dangerous of the state’s 59 subspecies.
The state health department reported more than 100 cases of mosquito-borne disease in Ohio in 2017, including 27 of West Nile and 52 of malaria.
“What we have now is a foot in the door,” Denlinger said. “In terms of down-the-line implication, if you could turn a mosquito into a vegetarian, that would be something.”