Insects and Flowers 



5 6 3 



of plant-feeding insects, the leaf-eating beetles and locusts and caterpillars, 

 the sap-sucking bugs and plant-lice, the plant furnishes food alone; and 

 in furnishing it, under a rough compulsion, is nearly always the loser, even, 

 often enough, to death. The special relation between insects and plants 

 to which this chapter is devoted is also a kind of food relation, but with the 

 unusual character of being one in 

 which the plant is not at all a loser 

 but a gainer, and in as great measure 

 as the insect itself. Only plants with 

 flowers and mostly only those with 

 bright-colored, odorous, and nectar- 

 secreting flowers, have any part in 

 this relation, which is, as the reader 

 has already recognized, that interest- 

 ing phenomenon, the cross-pollination 

 of flowers by their insect visitors. 

 As this interrelation of flowers and 

 insects is one of very large importance 

 in the life of many insect kinds, pro- 

 found modifications of their structure 

 and habits depending on it, and as 

 popular knowledge of the subject is 

 likely to be extremely general in its 

 scope, I have thought it advisable to 

 present a brief special account of this 

 phenomenon. 



The agency of insects in effecting 

 the cross-pollination of flowers has 

 long been recognized. Credit is given to 

 Sprengel for first publishing accounts 

 of the interesting modifications of 

 flowers due to their interrelation with 

 insects, and for discovering that the 

 insects were instrumental in pollinating 

 the flowers. (Das entdeckte Geheim- 

 niss der Natur im Bau und in der 

 Befruchtung der Blumen, von Chris- 

 tian Konrad Sprengel, Berlin, 1793). 

 But that this pollination by insects was (nearly) exclusively cross-pollination 

 he did not apparently fully understand, or at least he did not fully under- 

 stand the significance of cross-pollination. It was reserved for Darwin 

 (On the Fertilization of Orchids by Insects, London, 1862), on a basis not 



FIG. 760 Snapdragon being visited by 

 honey-bees. (From nature.) 



