Re: Philippe Danton - Roridula

MARTIN HENERY (mhenery@rna.bio.mq.edu.au)
Fri, 4 Oct 1996 19:13:27 GMT+1000

>
> Now, about roridula : I read in my books that these plants are not
> carnivorous. True or false ? It seems that they extract no
> nutritives elements from the insects they "accidentally" catch.
> Could anybody explain me ?
>
> Laurent
>
>
Laurent, someone else recently mentioned an artcle from New Scientist
(August 31st, p. 16)
which describes an interesting mutualism between Roridula and an
hemipteran Pameridea roridulae. Apparently by placing insects labelled
with an isotope of nitrogen onto the leaves the scientists found that
the nitrogen disappeared from the flies they stuck on the plant and
reappeared inside the Roridula plant tissue. They then noticed that
an insect which feeds on other dead insects, Pameridea, was walking
around avoiding the sticky hairs with its long legs and secreting
urea onto the leaves as a waste product. Roridula then absorbs the
urea to supplement its nitrogen. The plant uses the hemipteran as a
sort of "surrogate gut" and the hemipteran is supplied with food:
Thus a mutualistic relationship. Roridula has evolved to be indirectly
carnivorous in partnership with an insect.
Note: This work has only just been published in a journal and
therfore would not be included in most CP reference books.

Hope this helps.

Martin Henery