ABSTRACT Greenhouse tomato (Lycopersicon esculentum Mill) production relies on pollination by commercially-produced bumble bee (Bombus impatiens Cresson) colonies. Inadequate pollination by bumble bees has been a problem for growers at certain times of year; however, its cause has yet to be determined. Bumble bees have been shown to exit tomato greenhouses to forage on flowers of other plants. This study investigates tomato's floral characteristics and their affect on bumble bee pollination by 1) observing foraging preferences for bumble bees on greenhouse tomato, 2) determining if the plant's floral advertisements could be used by the bees to estimate pollen availability, and 3) identifying temporal changes in floral display which correspond to peak bumble bee activity. Flower size (petal length, anther cone width, and anther cone length) and floral scent (release of β-phellandrene, 2-carene, α-pinene, and p-cymene) were evaluated to identify the pollinator-important characteristics of tomato flowers. Ou...