PAPERSTrends in plant-insect interactions in the Cenozoic »
Trends in plant-insect interactions in the Cenozoic
Academic Affiliation: Sophomore, Yale University, Geology and Geophysics
Science Research Mentor: Dena M. Smith - University of Colorado at Boulder
Writing and Communication Mentor: Freddy Blume - UNAVCO
Community Mentor: Marianne Okal - UNAVCO
Peer Mentor: Lennox E. Thompson
The Cenozoic era was a time of global-scale changes not only in climate, but also in the levels of angiosperm and insect diversity. Previous work on plant-insect relationships suggests that these temporal and climatic factors may have played a role in the evolution of such interactions. To test these hypotheses, a study of the patterns of insect mediated leaf damage was conducted by comparing six, well-preserved lacustrine deposits in western North America. The Cenozoic formations examined span a 30 million year time interval and have varying climate that allowed us to determine which variables might be better predictors of the amount and types of insect damage present in these fossil assemblages.
Two-thousand three hundred and ninety leaves were examined in total to measure overall damage levels for each assemblage, as well as damage levels for specific plant families. Plant families were chosen because they appeared in more than one assemblage, and this would provide a control for overall taxonomic differences that might exist between assemblages. For sites where greater information about the depositional environment was known, a chi-square analysis was used to further determine whether the position of a deposit relative to the lake margin had an effect on insect damage levels.
Neither overall assemblage damage levels nor damage levels within specific families were shown to correlate with climatic factors (temperature and precipitation) or age. Furthermore, significant differences in damage levels were recorded in a single lacustrine deposit depending on whether an assemblage was preserved near- or offshore, and whether it was on the east or west side of the lake. These findings suggest that there are many micro-scale climatic and environmental factors that must be taken into account and controlled for when making macro-scale time and space comparisons of insect feeding damage.