In many endangered wetland habitats, such as vernal pool habitats, significant ecological interactions are not well known. One ecologically important relationship in vernal pool habitats is the pollinator-plant relationship between spring flowering annuals (such as Blennosperma, Lasthenia, Limnanthes and Downingia) and their insect pollinators. This project examined aspects of the interaction between two vernal pool plant species, Downingia bella and D. cuspidata and their potential insect pollinators. Studies were conducted at the Santa Rosa Plateau Ecological Reserve in Riverside County, California in the spring of 2000. We examined the effect of spatial zonation of Downingia (edge vs. interior) and pan trap color on the kind and abundance of hymenopteran visitors caught. Downingia occurred in distinct spatial zones: D. bella grew in deeper areas and D. cuspidata grew in shallower areas of the pool. The dominant families of bee and wasp visitors caught were the Anthophoridae and Vespidae, respectively. There was no significant effect of zonation or trap color on the number of bees caught. However, there was a significant effect of zonation and trap color on the number of wasps caught. Studies conducted this past spring at the same site indicate that there may be significant year-to-year variation in the kind and abundance of insect visitors to both Downingia species. The local zonation patterns of both Downingia species appear to vary as well.
Keywords: Pollination ecology of vernal pool plants
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA