Insect Pain receptors

Pierre Zagatti zagatti at
Mon Dec 20 05:11:33 EST 1999

Yes, but there are true K-strategists in insects (e.g. tsetse flies)
and true r-strategists in vertebrates (e.g. cods and many fishes).
I don't believe their peripheric nervous afferences really differ from
their relatives showing the opposite strategy.

For my own, I am convinced that insects have pain receptors since I reared
stink bugs in the lab.
Wild bugs release defensive compounds through metathoracic glands (mainly
as soon as you approach them, open boxes or manipulate them (gently).
After one generation completely reared in the lab, you may handle them, gently
or not,
without smelling the characteristic odor, unless you wound them (we may
probably call this a 'taming' process).
There are probably some receptors in the integument that are stimulated in case
of wound.
The response (gland discharge and running away) might be essentially reflex
(no consciousness of pain), but the nervous inputs do exist and the 'taming'
process indicates
that the responses to stress are not always induced by the integration of
classical cues,
vision and olfaction.

I guess that everybody who reared sting bugs (many labs rear Nezara viridula in
the US)
did similar observations.

Kenelm Philip wrote:

> > If we wonder whether insects have pain receptors we should also wonder
> > why humans and vertebrates have pain receptors.
> Well, here we get into 'Just So' stories again. It would seem clear that
> long-lived K-strategists that have the ability to repair themselves would
> profit from a sense of pain--and vertebrates do indeed have specialized
> pain receptors in their nervous systems.
> Short-lived r-strategists that do not have comparable abilities for self-
> repair would not need to invest in such mechanisms. There's always one
> more individual... People have looked long and hard at insect nervous
> systems, and no pain receptors have been found, as far as I know. And there
> are some behavioral details that indicate insects are something very
> different from vertebrates. Decapitated humans don't do so well at bed-
> room sports, for example...
> > would be presumptuous to assume that insects don't have comparable
> > nervous system features.
> It's not so presumptuous when you look for something and don't find it.
>                                                         Ken Philip
> fnkwp at

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