This paper analyzes a highly contrasting situation, assessing the role of the butterfly Euphydryas editha as a pollen vector in the grassland habitat of Jasper Ridge Biological Preserve on the Stanford University campus. The availability of nectar resources is of major importance in the population dynamics of Euphydryas , and on Jasper Ridge E. editha is among the most frequent visitors to several abundant annual plant species which possess platform inflorescences pollinated by a wide array of insects.