Date: Tue, 29 Aug 2000 09:27:10 +0000 From: schlauer@chemie.uni-wuerzburg.de To: cp@opus.hpl.hp.com Message-Id: <aabcdefg2666$foo@default> Subject: Re: Carnivore or not Carnivore?
Dear Tony,
> Helliamphora is
> considered a carnivore, the same with Darlingtonia, also Brochinia.
Not for _Brocchinia_! (cf. previous discussions on this topic in the
archives)
> Why is Roridula then consigned to the class of 'sub-carnivore'?
> (along with Byblis liniflora)...... To my understanding the
> adaptations of all three are designed to gain nutrition from
> insect/invertibrate sources. None of these plants produce enzmes
> themselves to break down their prey,
Apparently, *some* species of _Byblis_ and of _Heliamphora_ do in
fact produce digestive enzymes. No recent investigations in
_Darlingtonia_ are known to me.
> yet Roridula has been classed
> as a sub-carnivore just on this fact alone. Is this just an odd
> peculiarity of modern classification, or is it that the CP's
> wouldn't want to see half of the plants they cultivate classed as
> 'not proper' carnivores?
Maybe any of these considerations plays a role here. The problem is
that Nature does not quite fit into strict man-made categories, and
there is in fact a continuous range of transitional forms from
almost pure autotrophs to orthodox, fully featured carnivores. This
has been discussed in great detail and even with a bit of remaining
controversy on this discussion list already, and I can only recommend
consulting the archives, in which you will find most of the arguments
and a few of the possible conclusions.
> I dare say this will annoy a few people out there, but I just can not
> see why these plants are classed differently,
Because they are different (there are in fact more differences than
classes).
> they all have adapted, along different paths to capture/utilise insects.
It is exactly these different paths that matter.
> In all respects, what is the difference in the end product if a plant
> uses bacteria to break it's prey down compared to capsid bugs?
The bacteria are apparently quite ubiquitous. If bacterial
decomposition was accepted as an adaptation by the plant to the end
of digesting animal prey, you could immediately classify more than
50% of all known plant species as carnivorous. This would not be the
kind of information that should be conveyed by the term "carnivorous
plant".
Kind regards
Jan
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