THE AMERICAN BOTANIST. 
57 
How Flowers Attract Insects.— It is usually as- 
sumed that color, odor and nectar are produced by plants 
to attract insects to the blossoms, but that the shape of 
flowers has reference entirely to making the insect 
approach pollen and nectar in the proper way. The 
assumptions in regard to the attractions of flowers, how- 
ever, have not gone unchallenged and a great many 
observations have yet to be made before the whole matter 
wiW be settled. Some observers have asserted that color 
is of no use whatever and that so long as flowers produce 
nectar the^^ will attract insects whether the petals are 
removed or not. On the other hand, the fact that practi- 
call3" all showy flowers are insect pollinated indicates 
that color must be of some value to the plant. It is well 
known that many insect-pollinated flowers do not pro- 
duce nectar. In such cases the insects visit the flowers for 
pollen. Many apparently odorless flowers attract num- 
erous insects but the fact that human beings fail to find 
odors in them is no reason for asserting that they are 
odorless. There are light rays that we cannot see and 
sound waves that we cannot hear, yet insects perceive 
them. In all probability there is an immense number of 
scents perceived only by insects. Possibly every flower is 
fragrant to them. So odor is probably the chief means of 
attracting the attention of insects, nectar and pollen the 
objects that cause them to visit the flower, and color the 
assistant that directs the insect at close quarters. We 
must at this point take into consideration the difference 
in color-perception found in various insects. Bees seem 
to have the most acute sense and it is noticeable that the 
flowers showing the greatest degree of specialization and 
colored blue or violet are most often pollinated by bees. 
The experiments that can be made along the lines here 
indicated are endless, and anyone who has a flower 
garden need never lack for occupation. The results 
obtained, it need scarcely be added, will be of the very 
highest scientific importance. 
