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Thursday, May 24, 2018

Snails and Mosquitoes

     What does this mean for the future? According to a recent (May 125th) New York Times article scientists at the University of California-Los Angeles reported that when they transferred molecules from the brain cells of trained snails to untrained snails, the animals behaved as if they remembered the trained snails’ experiences. 
     A professor of neurobiology at UCLA has been studying a type of sea snail that is about five inches long and its ability to make long-term memories . In experiments when these snails get a little electric shock, they briefly retract their siphons, which they use for expelling waste. A snail that has been shocked before retracts its siphon for much longer than one that hasn't. 
    Researchers discovered that when they tinkered with a trained snails’ brain cells in a way that should have removed their memory completely, some vestige remained. They extracted all the RNA from the brain cells of trained snails, and injected it into untrained snails and, lo and behold! The untrained snails kept their siphons wrapped up much longer after a shock. 
     Next, the researchers took the brain cells of trained snails and untrained snails and grew them in the lab and soaked the untrained neurons in RNA from trained cells, then gave them a shock, and they fired in the same way that trained neurons do. The memory of the trained cells appeared to have been transferred to the untrained ones. 

Question. If you keep swatting at a mosquito, will it leave you alone? 

    Also from a New York Times article, some scientists think so. It depends, they say. A mosquito may be willing to risk its life for a meal, but if there’s a more attractive or easier victim to feed from, a mosquito may move on. They say that if you keep trying and missing, the mosquito may learn to associate your swatting vibrations with your scent.
     Mosquitoes do not just bite anything according to a neuroecologist at The University of Washington. They prefer people over other animals and some people over others. Attraction depends on how a person looks, smells or acts. But when a feeding situation isn’t favorable, a mosquito can switch preferences.
     They ran some experiments and discovered that some initially attractive odors became threatening signals that the mosquitoes learned to avoid and chose to approach a new odor instead. For at least 24 hours, they retained this memory. 
    How do mosquitoes locate their prey? From far away, carbon dioxide from our breath draws them in and triggers their visual system to seek out high contrast objects as a potential meal. Up close, mosquitoes detect odor, temperature, sweat and even the presence of alcohol or pregnancy (pregnant women emit more carbon dioxide). If signs don't check out, the mosquito doesn’t bite. 
     The whole purpose of the experiments is to understand how mosquitoes process select hosts and then develop ways to control disease. Another possibility might be to impair learning in mosquitoes with insecticides or genetic tools.

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