MAY
1995

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

05-25-95

Mother Nature's Soap Opera

Insects and plants have developed what we might call a love/hate relationship.

On the hate side of the ledger, insects find plants to be a good food resource. Even the most casual of nature observers has at one time or another noticed an insect chowing down on some unfortunate plant. Excessive feeding by insects sometimes damages or even kills plants. That, of course, is not good for plants, and they do fight back with such things as bad tastes and fuzzy leaves.

On the other hand, some plants and insects have developed a relationship fit for the steamiest of TV soap operas — a love triangle. In the course of the 135 million years or so that insects and flowering plants have coexisted on this earth, these living organisms have, in the language of biology, "co-evolved." This means they live interdependent lives, one depending on the other for something essential to each's well being.

Many flowering plants have a sex life that depends on insects. These plants use insects in a role not unlike that of Miles Standish, who carried a proposal of marriage from John Smith to the Indian princess Pocahontas. This intermediary process apparently took Pocahontas by surprise, and prompted her return message of, "Speak for yourself John!" Plants, unlike Pocahontas, are willing to have the messenger deliver the goods and readily accept pollen carried by insects.

Insects are not willing couriers in this reproductive process; they must be bribed. The plants are more than willing to pay the piper for the services rendered and provide the insects with goods. The goods are in the form of nectar, a sugary reward for pollen transportation.

To make the system work, the plant doles out only small amounts of nectar from each flower. This ensures that the insects, most commonly the bees, must go from flower to flower to collect enough nectar to meet their carrying capacity for each trip. In the process, the insect brushes pollen from one flower onto the female parts of another flower and completes the fertilization process. A happy ending to this love triangle it appears, and in most cases it is.

There are exceptions, however. Some bees have learned to collect the nectar without providing services to the flower. These bees are called nectar thieves. They ply their trade by chewing holes in the base of the flower so they can remove the nectar without crawling down into the flower. This, of course, means the insect doesn't pick up pollen and fails to uphold the insect end of the pollination triangle.

Even in the insect world there is no honor among thieves, especially when sex and bribery are involved. Even Mother Nature appears to enjoy a good sex-and-crime soap opera episode from time to time.

 

Writer: Tom Turpin
Editor: Andrea McCann