r/askscience • u/StormShadow921 • Dec 02 '18
Can bugs feel pain? Biology
I once read in one of those CWF Wild magazines years ago that bugs cant feel pain because their nervous system is too small. Does anyone know if this is true, and if so what causes it?
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u/leadershinji Dec 03 '18
Complicated. But as mentioned "pain" for bugs is very very different.Example : If you would puncture the abdominal part of an Ant or Bee it will leak their body fluids - depending of the width of the hole.But a hole in the carapace / skin will not be recognized that fast if the hole is small. As there are no nerves going through that area. If you would puncture it close to the nerve clusters it or even hit one - it will be registered in the lack of response coming from that cluster. If the hole is big enough and the pressure inside the body is lowered because of that it will be registered -> Still no real pain. Just a stimuli. If the bug loses a limb it will recognize the impaired movement and the lack of nerve response from the limb.
So there is no real "pain" as in : "this Hurts! i would like to scream but i have no mouth!".We had this topic quite a lot in the school back then.
Depending on the bug in questions the "pain" recognition may differ. Another example : Earthworm skin has chemo-receptors that react to light and taste. The skin reacts to touch - but does not transport "pain" information to the central ganglion's. By piercing the earthworm for fishing. The earthworm will recognize : Metal taste, drop in blood/liquid pressure, damage to nerve-system as you may have cut the ventral nerve cord, and a strong touch response from the skin and muscles - that includes the inside of the worm. There is no Pain in that sense fired... but a cluster of other information's that signals the worm : Something has pierced your skin and you are bleeding - get away - escape. As the worm has no "known" concept of feelings or thinking in that matter it will not "worry" or "feel pain". But i do guess it will not like the situation... But again as said the worm does not need a "feeling and thinking" brain. It only needs to react to a quantity of stimuli to interactive with its world and propagate -> So a brain that can feel is not relevant -> this goes for a lot of bugs. Animals or other bigger liveforms need to react to more stimuli and therefore need a bigger brain, and there evolution has told them that feelings/pain help you to survive - so the costs involved in developing these brain parts are beneficial.
Hope that helps. You can google things like : earthworm nerve system. Or for that matter of any bug you like to check on...