Nepenthes genetics

[mrmiller]

I have a question I've been pondering for a while regarding the genetic diversity among Nepenthes species.  I thinks its safe to say that in general many species of Nepenthes are fairly variable in picture characteristics and other traits.

My interest rises in the fact that since most Nepenthes are inter-breedable (not sure if thats a word

) is there a possibility that some of the variation in a species of Nepenthes comes from mixed genes from other species.  Take as an example N. alata.  Is it possible that many dozens or even hundreds of generations ago certain populations of N. alata mixed with another species, thus leaving some genetic remnants in those population today?  Im not claiming that any of the current species of Nepenthes are actually hybrids, Im just wondering if certain variable populations may have arisen not through independent evolution but through introduction of traits from other species.  An example would be something like a form of some Nepenthes, say N. alata, that might be variable because it contains like 0.03% DNA from some ancestral hybridization.

It would be interesting to do an analysis of the Nepenthes species taking a look at which species are more notoriously variable than others and see if the most variable species exist in areas closely inhabited by other species where such ancient hybridizations could have been possible.  On the same note, it would be interesting to look at very geographically isolated species to see if they are less variable.

Just a thought.  Id love to hear people's opinions on this matter.

Thanks,
Matt Miller

 

[pthiel]

Matt,

I see what you are saying and believe you have a good point. But on the same hand how much variation occurs due to environmental difference in the conditions the plants grow under. I have taken cuttings from plants and then placed the cuttings into different media, used different light intensity, photoperiods, temps and humidity and the plants will show alot of variation in pitcher shape and coloration.

My 2 cents.

cheers,

 

[mrmiller]

Hi Pete,

I agree with you, I don’t think there is any doubt that environmental factors play a big role in the development of many Nepenthes characteristics.

I also wanted to point out two more evolutionary aspects of Nepenthes that I have speculated about.

The first is that there may be natural selection pressures that stimulate wide diversity of species in Nepenthes habitats.  Of course species that are geographically isolated will develop over time in often totally different directions as far as pitcher shape is concerned.  I think however, it is interesting that many species which live in close ranges to one another or are even mixed together in their natural habitats have strikingly different pitcher characteristics.  I would assume that these species once shared the same common ancestor that first colonized their habitat.  A possible source of radically different pitcher characteristics in these species may be prey competition.  Differentiation of pitcher types could be encouraged because different species of insects are likely to be attracted to different colors, shapes, and odors in Nepenthes pitchers.  I read an interesting article describing the partitioning of prey among N. rafflesiana and N. gracilis, two species with very different pitcher characteristics that live together in certain areas.

Another interesting idea is that once Nepenthes species have begun to diversify, there may be selection pressures that keep them from remixing their genes (A countering force to my topic above).  I understand that there are many other factors which affect the mixing of species such as differential timing for flowering and differential attraction of pollinators.  However, I have noticed that often when two very distinctly different species (species with very different pitcher characteristics such as large vs. small pitchers) are hybridized, the hybrids can be very bland (of course there are cases where this isn’t true)  Is it possible that this is another factor that helps differentiate Nepenthes species, their mixed offspring are not as showy or specialized and therefore attract less prey than either parent.  These factors would weed out much natural hybridization over time and keep the gene pools of highly diversified species living together separate.

I believe that there are several growers out there in the world who try to develop new and showy Nepenthes hybrids.  Is there anyone out there who is trying to develop new extravagant cultivars by selectively breeding within species lines?  (I understand that both of these directives, especially the second could take decades)

Also, I would like to mention that I am by no means an expert on evolution, phylogeny, or Nepenthes.  I am just making some observations.  I would love to hear what other people think or natural examples that support or refute these ideas.

Thanks,
Matt

 

[carnivorous23]

This might explain a little about hybrids becoming species.

http://www.cpjungle.com/nupsh.htm

 

[mrmiller]

Thanks carnivorous23,

The elevation of hybrids to species rank is indeed interesting although that is not what my previous posts are talking about. I would be very interested in hearing more opinions on this matter.

Matt

 

[pthiel]

Matt,

I see where you are going and it makes alot of sense. It would be interesting to see the resulting plants of natural hybrids and compare population to it's natural parent species. I would also like to if natural hybrids have the 'hybrid vigor' that so many of the manmade hybrids do - being able to thrive under more adverse conditions than the parent species.

Unfortunately that kind of information will require some of the folks who have access to the plants natural ranges to determine for us.

Cheers,