_Sarracenia_ toxicity/_Drosera_

Jan Schlauer (zxmsl01@studserv.zdv.uni-tuebingen.de)
Fri, 20 May 1994 10:38:56 +0100


>(...) but I was speaking of otherwise healthy ants that seemed to get so
>intoxicated from the nectar that they couldn't walk straight.(...) the purp
>seems to have something particularly intoxicating to some ants. I know other
>>CP nectar seems to do this, but I have never seen it so dramatically
>>demonstrated as in the S.purp.

WOW! I have not read about this particular phenomenon before. Could you or
someone else on this list perform a little experiment (= BIG favour) for
me? As I would like to know if the nectar secreted by _Sarracenia_p._ does
only stupefy the ants or if it does kill them, could you please try to
catch ants stunned by _S.p._ before they drop into the pitcher? The pitcher
fluids of some Sarraceniaceae do contain some detergent(s), and if the ants
were just stupefied they could be actually killed by the water entering
their tracheae when they drown in the pitcher. So it would be necessary in
order to test the potentials of the nectar itself to catch the KO ants
(previous to contact with pitcher fluid) and place them in some (dry/not
air-tight!) bottle from which they cannot escape, and just check if they
are still immobilized (= in all probability dead) the next day. The
experiment should be repeated with several ants to confirm results. It
would also be of interest if other insects/small animals do respond in a
similar way or if the nectar is specifically intoxicating ants.

Thank you very much.

> I do not exactly where it comes from, but it is possible to find this
> drosera
>in some protected areas in Central Europe.

>I beleive that D. rot. comes from europe if i remember correctly.

_Drosera_rotundifolia_ does have a circumboreal/temperate distribution (N
America, Europe, N Asia, with one strange exclave in New Guinea). The
question where it does come from (phylogenetically) is not an easy one to
answer. The closest relative is _D.anglica_, unfortunately (i.e. it does
not help very much to solve the problem of origin) with a somewhat similar
global distribution, only somewhat less represented in Asia, but present in
Japan. Because _D.a._ does have 2n=40 chromosomes (while most relatives
have 2n=20), it might be a hybridogenic (yet fertile!) species, involving
_D.rotundifolia_ and some other, presumably long-leaved species. As the
only recent species which could be the other parent (morphologically &
geographically) is _D.linearis_, occurring only in NE N America, this could
be close to the origin of _D.anglica_.

If _D.rotundifolia_ and _D.anglica_ have spread to their present ranges +/-
simultaneously (which does not seem completely unlikely to me), they could
have originated somewhere in N America and moved westwards (_D.a._ reaching
Japan, _D.r._ reaching further into Asia) and eastwards (both reaching E
Europe via N and C Europe, where _D.a._ seems to be somewhat more
successful in the S: Macedonia!). Remember however, as _Drosera_ seems to
be a rather old genus (certainly older than Lentibulariaceae), the
situation may have been completely different. In any event, Europe is
rather certainly not the place of origin of any member of _Drosera_ (e.g.
no endemic species, but mind _Drosophyllum_!).

>Then the miracles begin to happen after years: spontaneous appearance
>of Sundew. (D.rotundifolia isn't it? round leaves 5mm, rozet 5cm max.)
>This happened four or five times on different places.
>Now they are 'all over the place'.
>It must spread underground I believe.

It is quite likely that _D.rotundifolia_ can reproduce from underground
parts (stems, and even roots!). But from the diagnosis and the rather
characteristic behaviour, I would rather think you are talking about the
"Round Leaved Nasty CP Greenhouse Weed" (vulgo _D.spatulata_, the long
leaved counterpart being _D.capensis_). This one comes with the soil
(predominantly of nursery cps). Do you have cp from a nursery (i.e. not
from the wild)?

Kind regards