Your cheatin heart Nonmutualism pollinators

Some plants don't play fair. They cheat to get what they want and leave the poor, gullible insects no better off for their trouble. Basically, the plant tricks the pollinator into visiting the flower with the promise of a good time or a good meal and then doesn't pay up. As you can imagine, the interactions between these plants and their unsuspecting pollinators are not mutualistic; one of the partners is coming out behind. In these cases, co-evolution acts to make the plant better at deceiving the pollinator and the pollinator better at not being deceived.

A couple of examples:

^ Some plants have flowers that smell like rotting meat. These flowers are pollinated by flies and beetles that arrive expecting to find a carcass. Instead, they end up getting a dusting of the flower's pollen, which they deposit the next time they make the same mistake.

^ Several species of orchids have evolved the ability to attract male insects by mimicking the sex pheromones, and sometimes the shape, of the female insect. Imagining what happens in this case is easy: The male insect pounces on the orchid and makes a really good attempt at mating with the flower, getting covered with pollen in the process. In the end, he gives up because the process just isn't going very well and flies off to find a different female. But he may end up on another orchid and transfer the pollen that he picked up on the first orchid.

Don't blame the poor male insects for being clueless. The compounds that the female insects use to attract males are actually very similar chemically to the waxy substances that the orchid uses to avoid drying out. You can easily imagine how at some point, one or a few mutations resulted in an orchid that smelled good in a whole different way.

0 0

Post a comment