How biting bugs use heat sensors to hunt prey
The discovery of a temperature sensor in fruit flies could help scientists understand how mosquitoes and other insects find warm-blooded targets—like humans.
This previously unknown molecular sensor belongs to a protein family responsible for sensing tastes and smells.
These types of sensors are present in disease-spreading insects like mosquitoes and tsetse flies. The discovery by researchers at Brandeis University is published in the journal Nature.
Biting insects, such as mosquitoes, are attracted to carbon dioxide and heat. Notice how mosquitoes always seem to bite where there is the most blood? That is because those areas are the warmest, says Paul Garrity, a professor of biology in the National Center for Behavioral Genomics at Brandeis who co-authored the paper.
“If you can find a mosquito’s temperature receptor, you can potentially produce a more effective repellent or trap,” Garrity says. “The discovery of this new temperature receptor in the fruit fly gives scientists an idea of where to look for similar receptors in the mosquito and in other insects.”
Smell and taste
The newly discovered sensor belongs to a family of proteins, called gustatory receptors, that have been studied for over a decade but never linked to thermosensation, Garrity says.
In previous studies, other gustatory receptors have been found to allow insects to smell carbon dioxide and to taste sugar and bitter chemicals like caffeine.
But in fruit flies, one type of gustatory receptor senses heat rather than smell or taste. This receptor, known as Gr28b, is responsible for sensing external temperatures and triggering a quick response if temperatures exceed the fly’s comfortable temperature zone, Garrity and his team discovered.
The research also reconciles previously conflicting views of how a fruit fly senses warmth, by showing that the insect has distinct external and internal systems for thermal detection.
Related systems are likely present in other insects, including those that spread diseases like malaria and sleeping sickness that kill hundreds of thousands annually.
The more scientists understand about how insects respond to and sense heat, the better they can understand insect migration in response to rising global temperatures and the spread of disease through insect bites.
Source: Brandeis University