Meeting Abstract
Biotic and abiotic forces govern the evolution of trophic niches, which profoundly impact ecological and evolutionary processes and species biology. Herbivory is an interesting niche because there are theorized trade-offs associated with diets comprised of low quality food that might prevent the evolution of herbivory in certain environments. For this study we investigated trophic niche evolution in Clupeoidei (herrings, anchovies, and allies) and tested the hypotheses that herbivory is negatively correlated with salinity and latitude using a novel, time-calibrated molecular phylogeny, trophic guilds delimited using diet data and cluster analysis, and standard and phylogenetically-informed statistical methods. Phylogenetic comparative analyses did not identify significant negative correlations between latitude and herbivory or salinity and herbivory. In clupeoids there were five evolutionary transitions from non-herbivore to herbivore trophic guilds and no transitions from herbivore to non-herbivore trophic guilds. There were no transitions to zooplanktivore, the most common guild, but it gave rise to all trophic guilds, except algivore, at least once. Transitions to herbivory comprised a significantly greater proportion of trophic guild transitions in tropical/subtropical relative to temperate areas. These findings suggest that cold temperatures may constrain the evolution of herbivory and that herbivory might act as an evolutionary “dead-end” that hinders subsequent trophic diversification and zooplanktivory an evolutionary “cradle” that facilitates trophic diversification.
