At each of the Evolution meetings over the last few years, anole researchers have been honored with some of the major awards (1, 2, 3) recognizing talented young scientists. That trend continued here in 2014, when Travis Ingram was named as one of the winners of the American Society of Naturalists’ Jasper Loftus-Hills Young Investigator Prizes.
Travis made a 30-minute presentation on his work on adaptive radiation. This work has combined the development of new analytical methods along with detailed analysis of two systems, our beloved anoles as well as Pacific rockfishes. In particular, Travis spoke about research investigating two questions: the extent to which adaptive divergence occurs specifically during speciation events, and the degree to which within adaptive radiations, convergent evolution occurs to the same adaptive peaks. In considering this work, Travis also discussed the difference between what are called “alpha” niches, which refers to ecological differentiation between co-occurring species, and “beta” niches, which refers to ecological differences across a landscape or environmental gradient.
Travis first discussed the method in to determine the extent to which morphological variation among species evolved during speciation. Travis has already published work on rockfishes that shows that substantial proportions of morphological variation among species appears to have evolved during the speciation process. He then discussed new work asking the same question in anoles, which shows that variation in traditional ecomorph traits—related to differences in structural habitat use—seem to be little correlated with speciational evolution. In contrast, climatic niche evolution—the divergence that arises within ecomorph clades—seems to be largely speciational.
Travis then switched gears to discuss research on convergent evolution within adaptive radiations, for which he and colleagues have developed a new method, Surface. Application of this work to Greater Antillean anoles—published in Science last year—shows that there have been 29 peak shifts in anoles, that there are 15 separate adaptive peaks, and that eight of these peaks have been occupied convergently. Moreover, Travis pointed out that even though the method does not start out with a priori categorization of species to ecomorph, the tradition ecomorph categories are for the most part recovered in the analysis, with some exceptions.
Travis then presented new work applying the same method to rockfish radiations on both sides of the Pacific in the northern hemisphere. Again, many convergent peaks were found; however, of the nine convergent peaks, eight were occupied by multiple lineages with a lineage, and only one occupied by lineages in both regions. This work was published this year in the American Naturalist.
Travis summarized by noting the interesting differences found in the two aspects of adaptive radiation he studies. His work indicates that axes related to environmental gradients, i.e., the beta niche illustrating differences across space, are related to speciational evolution, whereas traits related to alpha niche (microhabitat partitioning) are related to convergence within radiations.