The amount of Ultraviolet radiation B (UVB) reaching the Earth’s surface has been changing over the past few decades due to the destruction of the stratospheric ozone layer, increased air pollution and cloud coverage.  Current changes in the environment may lead to the evolution of adaptive plastic responses in plants and as well as influence interactions of plants with other organisms, such as insect herbivores.  However, potential plant evolutionary responses to environmental change will likely depend on the underlying genetic variation that is present in a population.  Here, we present preliminary data from a common garden experiment in which recombinant inbred lines of Arabidopsis thaliana were exposed to two different levels of UVB radiation (i.e., ambient- and excluded-UVB) and natural levels of insect herbivory.  We specifically addressed whether there was genetic variation in the response of A. thaliana RILs to UVB radiation and whether UVB variation influenced patterns of plant utilization by insects in the field (i.e., order of insect colonization, plant damage and fitness).

Results/Conclusions

Our results indicate that RILs exposed to excluded-UVB were colonized first by insect herbivores and received higher levels of insect herbivory.  However, insect herbivore impact was low in this experiment and thus, it did apparently not affect plant fitness.  In fact, plant fitness was higher in excluded-UVB plots, likely as a result of increased plant growth in plants grown under reduced-UVB levels.  In addition, we found genetic variation in all measured plant responses to UVB light, which is essential for potential plant evolutionary responses to future changing environments.