Due to the rise of monoculture in agricultural production, insect biodiversity has sharply declined in agroecosystems due to the reduction in host plant biodiversity. This includes declines in populations of native pollinators, which reduces the ambient pollination services received by crops and increases the reliance on managed pollinators like European honeybees (Apis mellifera). One way to combat this decline in pollination services is to develop crop varieties that have high attraction to pollinators, this can have a dual effect of inducing native pollinators to move deep into agricultural fields from adjacent habitats like woodland or meadow strips, as well as retaining managed honeybees within crop fields and improving their efficacy. Attraction can be determined by many traits including floral morphology, pigmentation, and chemical cues like fragrance. Under higher ambient temperature the floral temperature rises, resulting in several potential effects. A warmer flower is likely to emit a larger volume of volatile compounds, as well as to be an attractive resting place for ectothermic pollinators, and yet high floral temperature may reduce pollen viability. The goal of this study is to first assess the effects of floral traits, particularly morphology and pigmentation, on floral temperature relative to ambient conditions, and secondarily, how flower temperature differentials alongside floral traits may affect pollinator foraging preferences. Our findings indicate that floral morphology and pigmentation both influence floral temperature differentials, and that floral morphology, pigmentation, and temperature differentials influence visitation by native pollinators (bumblebees and sweat bees). Floral traits and their influence on temperature are potentially important targets for the improvement of pollinator visitation to sunflower cultivars and the improvement of yields.
Bachelor of Science (B.S.)
College of Sciences
Length of Campus-only Access
Makarenko, Alina, "Effects of Sunflower Pigmentation and Morphology on Floral Temperature and Pollinator Visitation" (2023). Honors Undergraduate Theses. 1464.