S07 - Session P2 - Understanding ecological relations among pollinators and nativars: a case study using Asclepias (milkweed)

Authors: Justin Peterman *, Marc van Iersel

Human intervention, in the form of controlled plant breeding, has resulted in significant and sudden phenotypic changes to many native species with ornamental value. Traditionally, ornamental cultivar introductions have been developed by selecting for increased inflorescence, longer bloom time, novel foliage, increased branching, and/or dwarfing tendencies. Conversely, in their native environments, these same species have coevolved alongside insect species and/or populations to develop plant-pollinator interactions. Some researchers have suggested that changes to plant phenology, morphology, and floral chemistry (based upon human selection for ornamental traits) could affect this evolved balance, but to what extent is still unclear. A growing market has emerged for cultivated lines of native plants, termed nativars, that are easy to grow and also serve functional ecological roles in suburban and urban environments. This study investigates the potential ecological value of interspecific lines of Asclepias (milkweed) that have been selected for the ornamental trade. By comparing floral traits such as nectar chemistry, floral area, and flower color with pollinator abundance, richness, and diversity, in nativar and wild-type species, insight is given into considerations that should be made at the intersection of ornamental interest and ecological value.