Insect Pain receptors

[Michael Gochfeld]

I think there's a word for this kind of philosophical argument. 

If we wonder whether insects have pain receptors we should also wonder 
why humans and vertebrates have pain receptors. 

If we believe they are adaptive (helping survival in sometimes hostile 
environments) then it would be presumptuous to assume that insects don't 
have comparable nervous system features. 

Earthworms (I know they're not insects) certainly wriggle when impaled 
on a hook. Is that pain? or reflex? or does it matter?

More important probably is whether they are conscious of pain. Not too 
long ago conventional wisdom held that only humans had consciousness. 
Don Griffin's classical book on "The Question of Animal Awareness" 
(1976) was greeted with substantial doubt and even hostility (except 
from pet owners who knew it all the time). 

M. Gochfeld