Bee Fascinated

There is a lot of snow on the ground around Chicago, and temperatures are in the deep freeze.  But there are hundreds of bees in nests spread over our landscape that are all comfortably feeding on the honey they have stored away for the winter.  How do bees create this great store of food? 

Bees forage for nectar and pollen among the many flowers in our backyards.  Nectar, a sugary fluid secreted by plants to attract bees and other pollinators, is sipped by worker bees for quick energy.  It is also collected and brought back to the nest to be mixed with enzymes secreted by the bees to form honey.  Pollen, a fine, powdery substance used in flower reproduction, is composed of amino acids, vitamins and fat that are all essential for bees.  Together with honey, it can be stored for long periods in the nest to provide food for winter.

When visiting a flower for nectar, a bee collects pollen on the hair covering its body.  They will brush the pollen from the hair into collection baskets on their legs.  A bee will visit from 100 to 1000 flowers to get a full load of pollen before returning to the nest to deposit it.  A single load takes 30-60 minutes to collect, and the bee will make an average of 10 trips a day.  There are thousands of bees foraging every day, and as each bee enters a flower patch, she can be most efficient if she knows which flowers have a full load of nectar and pollen available. 

Flowers are constantly refilling their nectar tubes during daylight hours.  Different flowers produce nectar at different rates from two minutes for borage, Borago officinalis, to almost 24 hours for bird’s foot trefoil, Lotus corniculatus.  The nectar is not visible, located in a long, slender tube at the base of the flower.  A bee will crawl into the flower and drink from the tube using her long tongue.  Foraging bees will not land on a flower that has recently been emptied of nectar, but how do they know which flowers to skip?

All insects are covered with an oil giving each species a particular scent.  Studies show that after carefully washing the feet of several bees in a mild solution and painting this solution on flowers full of nectar, foraging bees avoid these flowers.  The bees can smell the scent left by a previous visitor, can tell how old the scent is, and know how long that particular flower species takes to refill the nectar.  Footprint odor has also been identified as an aid to the bees when they return to their nest.  Landing close by the opening, bees walk the last short span, using scent to guide them to the exact spot of the nest opening.

Bees require large numbers of flowers for nectar and pollen to feed their colony.  They have thrived quite well up until the last hundred years when there has been a shift toward fewer flowers in both farmland and urban areas.  In the agricultural areas, before mechanized plowing, many fields were bordered by flowering plant species.  Since the automated plow, borders have been removed in favor of planting as much crop as possible.  Along country roads, flowering edges are often mowed.   In urban areas, the popular movement toward more lawn has also removed many flowering plants, especially in city parks and other recreation areas.  These changes greatly reduce the amounts of pollen and nectar available to bees.  You can make a difference in your own backyards by planting flower beds or areas of ground cover using flowering species.