Stories
Slash Boxes
Comments

SoylentNews is people

posted by martyb on Sunday February 09 2020, @01:07PM   Printer-friendly
from the too-late-for-agent-pleakley dept.

Common wisdom is that mosquitoes use multiple methods to home in on their prey, including Carbon Dioxide in respiration and detection of body heat. Now, in a paper published in the journal Science, researchers describe the underlying temperature detection mechanism used, and interestingly it isn't a heat-seeking mechanism, but rather a cold-avoiding one.

[...] Last year, [professor of biology Paul Garrity, Ph.D.] and several colleagues published a paper in the journal Neuron that upended the conventional thinking about the temperature-sensing receptors at the tip of flies' antennas.

Traditionally, these receptors were thought to act like thermometers, taking the temperature of the surroundings to let the fly know if the environment is hot or cold. Instead, Garrity and his colleagues found that the receptors only detected whether the temperature was changing, letting the fly know if things were getting hotter or colder.

For this reason, Garrity renamed these temperature sensors the Cooling Cells and Heating Cells. They're so sensitive they can detect a few hundredths of a degree change in temperature per second.

Mosquitoes, who are close evolutionary relatives of flies, also have Cooling Cells and Heating Cells.

While it would seem to make sense to look at the insects' heating cells to understand what draws them to human warmth, Garrity's group considered an alternative —- and counterintuitive —- hypothesis. Maybe it wasn't that the insects were flying toward the heat; maybe they were flying away from the cold. This would mean the Cooling Cells would be the ones to focus on.

The specific Cooling Cells Garrity and his fellow scientists studied for their paper in Science rely on a molecular receptor called IR21a. IR stands for ionotropic receptor, a group of proteins that help neurons to transmit signals. IR21a facilitates the transmission of a signal that the temperature around the insect is falling.

Here is a YouTube video comparing the ability of mosquitoes with and without the IR21a receptor to find a human temperature surface.

According to Garrity, the IR21a receptor is activated whenever mosquitoes move toward a cooler temperature. Since humans are usually warmer than their surroundings, this means that as a mosquito is approaching a human, IR21a is silent. But if the animal should deviate from its course and start to move away from its warm-blooded prey, IR21a becomes activated, only shutting off once the insect course-corrects.

Garrity said IR21a seems to act like "an annoying alarm. It goes off whenever the female mosquito heads towards cooler climes. When they are seeking humans, they seem to be driven to do whatever it takes to turn down the sound."

Also at Ars Technica and EurekAlert.

Now let's figure out how to hit 'snooze'.

Journal References:
Mosquito heat seeking is driven by an ancestral cooling receptor [$], Science (DOI: 10 .1126/science.aay9847)
In the heat of the night [$], Science (DOI: 10.1126/science.aba4484)


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 0) by Anonymous Coward on Sunday February 09 2020, @10:48PM (3 children)

    by Anonymous Coward on Sunday February 09 2020, @10:48PM (#956186)

    So they have a preferred temperature range. Calling it 'heat seeking' vs 'cold avoiding' seems like semantics to me.

  • (Score: 0) by Anonymous Coward on Sunday February 09 2020, @10:58PM

    by Anonymous Coward on Sunday February 09 2020, @10:58PM (#956191)

    Calling it 'heat seeking' vs 'cold avoiding' seems like semantics to me.

    I see. Blinded by semantics while missing the meaning.

  • (Score: 2) by Runaway1956 on Monday February 10 2020, @08:08AM (1 child)

    by Runaway1956 (2926) Subscriber Badge on Monday February 10 2020, @08:08AM (#956282) Homepage Journal

    There is always the possibility that the researchers are dumb as rocks, and spewing nonsense.

    Let's assume though, that they know what they are talking about. The bug has two types of sensors. The first sensor guides them toward heat, the second sensor screams at them if thermal energy is decreasing. So, no, not just semantics. The first sensor seems to cause good-feelz, and the second sensor causes bad-feelz. Apparently, the bad-feelz take precedence over good-feelz. If all of that is true, and accurate, then cold avoidance reinforces heat seeking, but it is a different stimulus.

    Which leaves a question to be answered: Why does the bug leave you after it has dined? Does the full belly turn off the cold avoidance system? Does that system only work when the female mosquito needs a blood fest to lay her eggs? Something is going on that these guys aren't explaining.

    --
    Make an actual interesting, germane, and relevant point and you may get away with Flamebait - 'Zumi
    • (Score: 0) by Anonymous Coward on Monday February 10 2020, @11:48PM

      by Anonymous Coward on Monday February 10 2020, @11:48PM (#956605)

      So their preferred temperature range changes after they eat.