Science News

Flies Flee In A Fear-Like State When They’re About To Be Swatted, Study Finds

Fruit flies flee from waving hands and flyswatters in a fear-like state, according to a recently published study conducted by researchers at the California Institute of Technology (Caltech).

While it might be a stretch to say that flies experience emotions, Caltech biologist David J. Anderson claims that the study’s findings suggest that they do, at the least, experience a fear-like state when they’re about to be swatted.

Anderson was quoted by the NY Times as having said, “When a fly responds to a visual threat, it isn’t just a robotic flex; there is some sort of internal state that develops”.

When a fly responds to a visual threat, it isn’t just a robotic flex; there is some sort of internal state that develops (…) If you’re hiking and hear a rattlesnake, your heart is going to pound and you experience fear long after the snake is gone (…) That’s persistence.

Researchers behind the study, which was published in the journal Current Biology, created an apparatus used to pass a dark paddle across the flies’ habitat in an attempt to gauge whether the flies would display the basic building blocks of emotions— or what are known as emotion primitives.

William Gibson, a Caltech post doctoral fellow and lead author of the study, was quoted by Discovery News as having explained the emotion primitives of fear as follows:

For fear, the first basic characteristic is that the fear is persistent.  For example, if a person hears the sound of a gun, the feeling of fear that it provokes will continue for a period of time (…) The second is that fear is scalable; the more gunshots a person hears, the more afraid he or she will become (…) The third is that fear is generalizable across different contexts, but it is also (the fourth) “trans-situational.”  Once you’re afraid, you’re more likely to respond in fear to other triggers: the clang of a pan, for instance, or a loud knock on the door.

In the study, researchers noted that the flies displayed all five emotion primitives.  For instance, at each pass of the paddle, the flies would jump and then run away, exhibiting persistence.  With each new pass, they were also quicker to flee, suggesting scalability.

While the scientists themselves have refrained from calling the reaction of the flies “fear,” they have gone as far as to say in conclusion that the stimulus did induced a fear-like state in the flying insects.

The researchers will be continuing the study using imaging technology intended to monitor brain activity in an attempt to identify the neural circuitry necessary for emotion primitives.

A better understanding of the neural pathways of fear could lead to treatments designed to aid those afflicted with nervous disorders and perhaps even mood disorders such as depression.

In other insect related coverage here on Immortal News, a biodiversity survey discovered 30 new species of flies in Los Angeles, California.

What do you think, do flies have feelings?

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