NEW ZEALAND'S EXPERIENCE WITH THE RED 

 CLOVER AND BUMBLEBEES. 



By S. Graenicher. 



The red clover Trifolium pratense L. is one of the numerous 

 flowers, that depend more or less on the visits of bumblebees for 

 their pollination. Darwin 1 expressed the opinion that these were 

 the only insects capable of effecting cross-pollination, but Herman 

 Mueller 2 presented a list of 39 visitors to these flowers, and stated, 

 that although bumblebees are considered the most important polli- 

 nators, there are quite a number of other insects, the visits of 

 which may produce the same results. Knuth 3 reproduces Muel- 

 ler's statements as follows : "In order to reach the nectar legiti- 

 mately, an insect must have a proboscis of at least 9-10 mm. in 

 length, corresponding to that of the corolla-tube. Many species 

 of bumblebees and other bees are regular pollinators, and some 

 Lepidoptera are casual agents of cross-pollination. The pollen, on 

 the other hand, is accessible to all short-tongued insects which 

 are skillful enough to depress the carina. Such insects, e. g., the 

 honey-bee, also effect regular cross-pollination. Nectar is also 

 stolen from the red clover, especially by Bombus tcrrcstris (with 

 a proboscis only 7-9 mm. long), and the honey-bee (with a pro- 

 boscis of 6mm.). These perforate the flowers from without, and 

 thrust their proboscis through the hole to the desired booty. The 

 opening is made use of by other thieving insects." 



On account of its importance as a food-plant the red clover, a 

 native of Europe, has been introduced into many, if not all, coun- 

 tries where cattle are raised. In New Zealand, a country originally 

 without bumblebees, the experience with the red clover was at 

 first not at all satisfactory, and it was therefore deemed necessary 

 to import bumblebees from Europe. A letter from the New Zea- 

 land Government, emanating from the Canterbury Agricultural 

 and Pastoral Association of Christchurch, New Zealand, dated 



1) Chas. Darwin, Origin of Species; Chapter III. 



2) Hermann Mueller, Die Befruchting; der Blumen, pp. 222-224. 



3) P Knuth Handbook of Flower Pollination (Engl, translation by 

 J. R. Ainsworth Davis); Vol. II, pp. 290-291. 



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