Do insects feel pain?

[Patrick Foley]

Nick,

Insects are closely related to Crustaceans. They have very complex 
nervous systems as can be seen by examining any standard text (R. F. 
Chapman 1998 The Insects: structure and function or Resh & Carde 2003 
Encyclopedia of Insects). Animal nervous systems all share many features 
including neuron structure, many neurotransmitters, CNS etc.. The main 
underlying differences between vertebrate nervous systems and protostome 
nervous systems have to do with the morphology and position of the nerve 
cord (theirs is a ventral ladder; ours is a dorsal tube), the 
development of different ganglia into differentiated brain activity 
areas (insects have mushroom bodies where higher learning seems to 
occur; vertebrates use parts of the cerebrum if they so choose), and 
brain size. What we call our 'pain receptors' are heat receptors, 
pressure receptors etc. Insects have lots of similar receptors.

What is harder to evaluate is the extent to which an insect brain 
creates a world view (and sense of self) that experiences the kinds of 
foreboding and suffering that mammals apparently do. This is a very 
tricky subject to study, so tricky that one could easily doubt that the 
the majority of humans are conscious! As for insects, I would put the 
fraction even lower. It has been seen in any number of classroom 
experiments (Don't yell at me, I am a population biologist, not a 
physiologist; these are not my experiments) that partially dissected 
cockroaches will go about their business afterwards in a way that seems 
very foreign to us mammals. Surely insects _respond_ to damaging 
stimuli. Whether there is something to be "aware" there is unclear. But 
the experience, if there is one, is surely qualitatively different than 
in mammals.

Frustrating as it may be to us higher consiousnesses, we are almost 
painfully ignorant of what truly goes on in the minds of insects, if 
they have minds.

Patrick
patfoley at csus.edu

Ron Gatrelle wrote:

>----- Original Message ----- 
>From: "Nick Greatorex-Davies" <ngd at ceh.ac.uk>
>To: <Leps-l at lists.yale.edu>
>Sent: Monday, May 23, 2005 5:15 AM
>Subject: Do insects feel pain?
>
>
>  
>
>>Hi,
>>
>>Can anyone answer this question for me please? I remember being told
>>that insects do not have pain receptors. Is this true? Clearly they are
>>able to 'feel' as they respond to various stimulae. Here in the UK there
>>are many well-meaning conservation minded people who talk of being cruel
>>to insects, of causing them pain, or of insects being distressed. Any
>>thoughts or solid factual information please?
>>
>>Many thanks
>>Nick Greatorex-Davies
>>CEH Monks Wood, Abbots Ripton, Huntingdon UK
>>    
>>
>***************
>
>No, they do not.  They don't feel anything as higher animals do.  Their
>rudimentary nervous system is not capable of this.  A response to some
>stimulation is far different than "feeling".  There is no need to give
>citations as those who have anthropomorphosized and romanticized "bugs" are
>not capable of accepting facts.
>
>Ron Gatrelle
>
>
>
> 
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