Zachary P. Cress
M. S. Student
Department of Biology
Texas A&M University
email: zcress@bio.tamu.edu

Research interests: Female mate choice in hybrid zones

My research investigates female mate choice and hybridization among the highland swordtail species Xiphophorus malinche and the downstream, lowland species X. birchmanni . I'm using videos of 3D animations of males with different combinations of phenotypes from each species and hybrid populations to gauge female visual preference and to determine if female preferences are congruent with actual male phenotypes.

I use Autodesk Maya 8.0 for all my modeling and animation. Here's the evolution of a 3D model of a pure X. malinche male . Sample videos will be uploaded as they are available. Click on the pictures for full-res images.


1. A wireframe is constructed out of basic polygon shapes.
For example, the body of this fish was originally a sphere and its tail was a cube.
Bones are added inside the mesh, which will later be used for animating the model.


2. This model is starting to look like a fish, but it doesn't have any texture yet.
High-res photographs of a fish are essentially pasted onto the mesh.
For models with recombinant hybrid phenotypes, photographs are digitally manipulated.


3. Now we're getting somewhere!

4. Here is the completed model. The next step is to animate.

To see a sample video, click here. Motion paths were created by rotoscoping and averaging the motion paths of live courting males filmed in the wild.