264 



AMERICAN BEE JOURNAL 



August 



Bumblebee Flowers 



By John H. Lovell 

 Photos by the Author 



MOST people suppose that all 

 flowers yield nectar and are 

 valuable as sources of honey. 

 A supply of nectar sufficient to meet 

 the wants of a small apiary is com- 

 monly thought to be afforded by an 

 acre of buckwheat or a large flower 

 garden. Beekeepers, indeed, are gen- 

 erally aware that many flowers fur- 

 nish only pollen ; but when it is re- 

 membered that not one beekeeper in 

 thirty takes a bee journal it is evi- 

 dent that the majority of them have 

 only a meager acquaintance with the 

 American honey flora. Even by the 

 more progressive beekeepers nectar- 

 iferous flowers adapted to bumble- 

 bees, moths and birds are often listed 

 as good honey plants. Bumblebee 

 flowers are so common and so wide- 

 ly distributed that no student of the 

 honey flora can afford to neglect 

 them, yet, if I mistake not. this is the 

 first paper on bumblebee flowers ever 

 published in an American bee maga- 

 zine. 



Of all bumblebee flowers the most 

 important and by far the best known 

 is red clover (Trifolium pratense). 

 When insects are excluded red clover 

 is almost wholly self-sterile, as can 

 be shown experimentally, for when 

 the plants are covered with fine net- 

 ting less than one-half per cent of 

 seed is obtained. The flowers are 

 pollinated chiefly by long-tongued 

 bumblebees, which under normal 

 conditions are alone able to obtain 

 the nectar. The floral tubes are 9 

 mm. long, which, of course, excludes 

 the honeybee which has a tongue 

 only 6j4 nim in length. Our domestic 

 bees quickly learn this fact from ex- 

 perience and seldom visit the clover 

 heads except when the corollas have 

 been shortened by dry weather or 

 other causes. When this happens, as 

 has been observed by Doolittle and 

 Hutchinson and others, hundreds of 





Fig. 3. Wild Columbine (Aquilegia 

 Canadensis L.) A bumblebee flower. 

 Photograph by John H. Lovell. 



pounds of red clover honey are 

 stored. Even in the same clover head 

 I have found by actual measurement 

 that the floral tubes vary in length, 

 and it would be little short of a mira- 

 cle if they did not, for flowers of all 

 kinds vary in size and consequently 

 in length of their petals. Honeybees 

 sometimes visit the flowers of red 

 clover to procure pollen, when they 

 spring the keel and effect pollination. 

 (Fig. 1). 



In lands where there are no bum- 

 blebees red clover seed cannot be 

 profitably raised for market until af- 

 ter these insects have been intro- 

 duced. In New Zealand, fields which 

 were almost barren in their absence 

 produced great quantities of seed 



after their advent. At Canterbury 26 

 acres of red clover were the resort 

 of thousands of bumblebees and 

 yielded 400 to 500 pounds of seed per 

 acre. In one province alone, in 1912, 

 610 acres were sown with red clover, 

 which it is estimated yielded an av- 

 erage of 158 pounds to the acre. Thus 

 bumblebees benefit the Islands of 

 New Zealand annually to the extent 

 of many thousands of dollars. 



A half dozen bumblebee flowers 

 are widely cultivated in flower gar- 

 dens. The stately larkspur, with its 

 wand-like raceme of deep blue flow- 

 ers, is a native of Europe, where it is 

 pollinated by the female of the gar- 

 den bumblebee, no other bee on the 

 wing at the time it blooms having a 

 tongue long enough to reach all the 

 nectar, although a part of it is ac- 

 cessible to a few other bees. I have 

 seen honeybees searching the flow- 

 ers and pushing their tongues down 

 into the long spurs as far as possi- 

 ble, but they were never able to gain 

 any of the sweet spoil. 



Then there are the aconites or 

 monkshoods. If you will take a plas- 

 ter cast of the inside of a flower you 

 will find that it corresponds almost 

 exactly to the shape of a medium- 

 sized bumblebee. This genus of 

 plants is so dependent on bumble- 

 bees for pollination that it is absent 

 from those parts of the world where 

 there are no bumblebees. For in- 

 stance, there are no native bumble- 

 bees in Australia, Arabia, Southern 

 Africa, or New Zealand, and in these 

 countries there are no indigenous 

 species of Aconitum. (Fig. 2). 



The columbines manage to thrive 

 and bloom under the most difficult 

 conditions of soil and climate. The 

 long spurs of the variously colored 

 pendulous flowers are rich in nectar 

 and are frequently visited by bumble- 

 bees. The columbines are often re- 



Fig. 1. Red Clover (Trifcjlium i)ra- 

 tense). Photograph by John H. 

 Lovell. 



Fig. 2. Monkshood (Aconitum Napellus). Photograph by John H. Lovell- 



