Case studies and mathematical models of ecological
speciation. 2. Palms on an oceanic island.
Sergey Gavrilets and Aaron Vose
Departments of Ecology and Evolutionary Biology, Mathematics, and
Computer Science, University of Tennessee, Knoxville, TN 37996
The study of a pair of sympatric species of palms on the Lord Howe Island
published by Savolainen et al. (2006a) is viewed as providing probably one of the most
convincing example of sympatric speciation to date. Here, we describe and study a
stochastic, individual-based, explicit-genetic model tailored for this palms system.
Overall, our results show that relatively rapid (< 50,000 generations) colonization of a
new ecological niche and sympatric or parapatric speciation via local adaptation and
divergence in flowering period are theoretically plausible if (1) the number of loci
controlling the ecological and flowering period traits is small, (2) the strength of selection
for local adaptation is intermediate, and (3) an acceleration of flowering by a direct
environmental effect associated with the new ecological niche is present. We discuss
patterns and time-scales of ecological speciation identified by our model. We highlight
important parameters and features that need to be studied empirically to provide
information that can be used to improve the biological realism and power of
mathematical models of ecological speciation.