How are bees attracted to flowers and which ones do they prefer

How do flowers attract bees?

Bees are primarily attracted to nectar-rich flowers by their color and, when they are closer, by their scent; and we know that bees and other pollinators are sensitive to the ultraviolet markings on flowers that guide them to the nectar-rich area of the flower, so they can collect the nectar in a minimum of time. Recent research has demonstrated that honey bees can learn to associate odors, colors, and patterns with food rewards, so we know that many elements go into choosing rewarding nectar sources. Bees will even locate nectar sources on a terrace in an urban high-rise; they have been seen as high as the thirty-fourth floor in Manhattan. Bees learn the location of rewarding food sites and will return to them regularly - terraces are no exception.

Are there any flowers that bees prefer or avoid?

In his research, Cornell University scientist Thomas Seeley found that honey bees focus on flowers with higher concentrations of nectar when there is plenty of nectar available, but they forage among a wider range of flowers when nectar is in short supply. Nectar volume, composition, and concentration vary among different species of plants and can wax and wane at different times in the flowering season of the plant and at different times of the day. Seeley's research indicates that most nectars are somewhere in the range of 15 to 65 percent sugar, and honey bees tend to prefer nectar high in sucrose over glucose and fructose.

The bees' own physical characteristics (morphology) apparently play a role in the choice of nectar sources for the stingless bees studied. Melipona beecheii has a yellowish body and these bees were observed to prefer sunny patches, while M. fasciata with its dark brown body preferred shady locations.

Mason bees, Chalicodoma sicula, studied by Pat Willmer in an arid area of Israel preferred more dilute nectar, and in that habitat collecting adequate amounts of water from flowers was more vital even than the energy reward of nectar. There are certain flowers that bees learn to avoid. Gustavo Romero and Craig Nelson studied a certain female orchid, Catasetum ochraceum, which receives pollen from a bee and then swells and closes up, creating a very limited opportunity for fertilization.

Male flowers of this species compete to be the one that fertilizes the female by rapidly heaping sticky sacs of pollen onto the back of any bee that visits. The large pollen sacks can weigh up to a quarter of the bee's bodyweight, and after one such experience, bees avoid male Catasetum and visit only females. Some related species exhibit similar learning behavior.

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