>>11154656>IIRC unlike some insects a fly will not favour an injured body partThere may be clear reasons as to why flies would or could not favor injured body parts. One being their lack of tactile sensing. Not favoring an injured body part may also only be the logical outcome of evolutionary processes since favoring it either has no actual effect on survival and especially procreation rates or may be even detrimental for the flies.
>that it's hard not to picture them as little circuit boards with wingsYou could say that about any animal or life-form in fact.
>Plant senses light. Turn towards light.>Cat sees mouse, must catch>Male human sees breasts, get aroused 
