Tuesday, June 30, 2009

Cali-Texan Hybrid Salamander Super Predator

A and B are the largest of the native california tiger salamanders. Note D is the hybrid. Holy shibbit. Picture from National Geographic.

Invasive hybrid tiger salamander genotypes impact native amphibians

1. Maureen E. Ryan (a,1)
2. Jarrett R. Johnson (a)
3. Benjamin M. Fitzpatrick (b)

a. Center for Population Biology, University of California, Davis, CA 95616; and
b. Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996

Abstract:

Although the ecological consequences of species invasions are well studied, the ecological impacts of genetic introgression through hybridization are less understood. This is particularly true of the impacts of hybridization on “third party” community members not genetically involved in hybridization. We also know little about how direct interactions between hybrid and parental individuals influence fitness. Here, we examined the ecological effects of hybridization between the native, threatened California Tiger Salamander (Ambystoma californiense) and the introduced Barred Tiger Salamander (Ambystoma tigrinum mavortium). Native x introduced hybrids are widespread in California, where they are top predators in seasonal ponds. We examined the impacts of early generation hybrids (first 2 generations of parental crosses) and contemporary hybrids derived from ponds where hybrids have been under selection in the wild for 20 generations. We found that most classes of hybrid tiger salamander larvae dramatically reduced survival of 2 native community members, the Pacific Chorus Frog (Pseudacris regilla) and the California Newt (Taricha torosa). We also found that native A. californiense larvae were negatively impacted by the presence of hybrid larvae: Native survival and size at metamorphosis were reduced and time to metamorphosis was extended. We also observed a large influence of Mendelian dominance on size, metamorphic timing and predation rate of hybrid tiger salamanders. These results suggest that both genetic and ecological factors are likely to influence the dynamics of admixture, and that tiger salamander hybridization might constitute a threat to additional pond-breeding species of concern in the region.

1. To whom correspondence should be addressed. E-mail: meryan@ucdavis.edu


I think this goes beyond introgression. That there is such a huge difference in phenotype is just amazing.

8 comments:

Sean Craven said...

You've just solved one of my life mysteries. A long time ago I bought a salamander from the Vivarium, a herptile-oriented pet store. It was thirteen inches long -- and they wouldn't tell me what the species was.

It had the color and markings of the hybrid in the photo you show here. Now I'm wondering if these hybrids were originally produced in captivity.

Zach said...

Are you sure this isn't a radioactive daikaiju-like salamander?

Metalraptor said...

And in thirty million years, we will have Neokoolasuchuses prowling the cold waters of the Pacific Coast. Muahahaha!

Will Baird said...

Sean: Delighted. I'm would NOT be surprised if they were hybrids that came out of accidents in someone's person aquarium.

Zach: yes, I'm sure. Dork.

Lewis: nah. They totally lack any way of going salt water. Alas. If they had /scales/ now...However, the inland water ways of the flooded california on the other hand...3m salamanders. *shudders*

Sean Craven said...

One of the more esoteric cryptids -- and one I really, really wish I could believe in -- is a type of giant (2-3 m) salamander supposedly found in the Trinity Alps.

Sigh. I can dream...

Sean Craven said...

Hey, Will!

I can't figure out how to email you directly -- so here's notification. I did a blog post on my salamander story and provided a link to this post. I hope this is okay... if not, let me know.

Unknown said...
This comment has been removed by the author.
Unknown said...

I have just found a Cali-Texan hybrid salamander on my front porch all the way in Santa Fe, New Mexico!!! Is it possible that they have migrated all the way here?? what are anyone's thoughts on this??