do insects also feel pain ?

It's a good question. It seems the answer is "probably".

 

"Available data are consistent with the idea of pain in some invertebrates and go beyond the idea of just nociception, but are not definitive." http://www.vliz.be/imis/imis.php?refid=212638

do insects also feel pain ?

William Shakespeare certainly thought so. In Act 3 Scene 1 of Measure for Measure he wrote:

 

And the poor beetle that we tread upon

In corporal sufferance finds a pang as great

As when a giant dies.

 

But then Shakespeare was no biologist …