Wild bee foraging abundance on native sunflower Helianthus annuus L. versus Helianthus cultivar sunflowers in an urban habitat

Through the months September-November of 2017 a study was conducted to determine if bees prefer the sunflower, Helianthus annuus, native to Arizona, or a cultivar Helianthus sunflower in an urban environment. The study was executed in a small, controlled urban environment on Arizona State University West campus. Seven identified bee species and forty-nine specimens were collected, of the forty-nine specimens, two bees were reported on the Helianthus cultivar supporting native floral host preferences of native species. Variables such as nectar, pollen, floral color, and floral height were not measured, however, when the floral host genus was maintained wild bees visited the native Helianthus host significantly more yielding a supportive two-tailed p-value of 2.97x10-5. Three trends were identified in correlation with the experiment: 1) Bees foraged on native Helianthus annuus over the Helianthus cultivar, 2) Generalist species were more abundant than specialists on the Helianthus annuus, 3) Honey bees (Apis mellifera) were the most abundant species present. While not considered a trend, low floral diversity and abundance may explain the low diversity of bee species observed on the Helianthus. Floral host and pollinator desynchronization may also have affected bee diversity and abundance. Analysis of bee abundance and diversity support that wild bees may prefer native floral hosts over cultivar floral hosts when the floral genus, temperature, and time was controlled for in an urban environment.