Re: CP evolution, volume II

Jan Schlauer (
Mon, 13 Nov 1995 11:10:19 +0100

Dear Fernando,

> Thus, I have never heard of studies proving that there really are
>specific prey or pollinators of Drosera in Australia, but I imagine this
>specialization does exist. So assuming these exist and adding the habitat
>specialization which is known to exist, I ask myself WHY do these exist?

I fear this question can not really satisfactorily be answered by science.

> Could it be that intense speciation and specilization is a
>natural result of the quick and forced evolution we discussed, caused by
>the changing climate in Australia over the past few million years? Why
>should the species become specialists and not remain generalists?

This one is somewhat easier. Rapid species diversification
("specialization") is a phenomenon associated with adaptive radiation. And
the latter process can be assumed to have occurred (not only in _Dosera_)
when the climate in W and later SW AU changed from temperate to
mediterranean type (creating new biotopes).

>Or is it better to have a large number of
>specialists to survive constant habitat changes?


> Is it possible for numerous generalist species to live together in a small
>area and compete for similar necessities?

Possible but more difficult (frequently leading to extinction of one or
several of these taxa).

> I wonder if the numerous Nepenthes species found in Borneo, for
>example, are each specialized in trapping specific prey, being
>pollinated by specific insects (which would be a natural barrier for
>mass hybridization), and growing in specific habitats (altidudes

Only the last seems likely (prey - mostly ants - and pollinators - mostly
flying insects - seem to be rather unspecific).

Kind regards