What is insect pollination? How do beetles and insects pollinate? Information on the importance of insect pollination.
Pollination by Beetles.—Various small beetles, representing thirteen or more families, are frequent visitors to flowers. With rare exceptions they are not specially adapted for feeding on flowers, and may derive most of their nourishment from other sources, such as sap, fruit, leaves, dung, and carrion. In flowers they chew on the soft tissues, eat the pollen, and lap up the nectar and other juices. They are attracted to flowers chiefly by odor rather than by sight. There is little regularity about their flights from flower to flower.
One type of beetle flower is large and solitary and composed of numerous spirally arranged petals, stamens, and carpels. Such flowers are usually pink, orange, or purple in color and have fruity, spicy, or fermenting odors. Nectar is secreted from the petals or stigma in some members of this class; in others, nectar is absent and the beetles feed on the tissues of the petals and stamens.
Another type of beetle flower is small and aggregated in an inflorescence. The petals and stamens are few in number. The individual flowers are inconspicuously colored green, white, or dull yellow, but they possess a powerful odor and make a fair showing by being massed in large numbers. Nectar is provided in a shallow basin where it is available to all comers.
Several beetle flowers, representing both the large and small types, are known to hold the beetles in a trap while the stigmas receive pollen and the stamens sprinkle a fresh supply onto the bodies of the prisoners. Thereupon a movement of the floral parts opens up an exit from the flower. Most beetle flowers have the ovules well buried beneath the floral chamber and thus protected from the chewing jaws of their pollinators.
The open and freely accessible form of many beetle flowers makes them the common camping ground, not only of beetles, but frequently of many other kinds of small insects as well, among them flies, wasps, bugs, and short-tongued bees.
As examples of the large and solitary type of beetle flower may be cited the magnolias and some of their allies, pond lilies including Victoria regia, California poppy, European chestnut, sweet-shrub (Calycanthus), and wild rose; and as examples of small and aggregated beetle flowers, dogwood, elder, spirea, and some members of the arum, parsley, and sunflower families. Beetle pollination is also reported in certain African cycads.