Using Smell to Attract and Chase Away Insects

Recent research found that some plants could chase away or attract pollinators by increasing or decreasing the concentration of their smell. Some of these plants know that just the right amount of smell to drive pollinators wild, but too much can drive them away. Scientists think that “plants tends to depended either on wind or on bees, birds, or other animals to carry pollen to female flowers, or in the case of pine trees and other gymnosperms, to female cones.” But how can these plants attract the pollinators or chase them away?

Ancient scientists thought that most of the plants were using chemical to attract their pollinators. In addition, they thought that cycads, which look like ferns or palms, were dependent on wind pollination. However, the male cones were very small, it was almost impossible for the wind to pollinate for these plants. Ecologist L. Irene Terry of the University of Utah, Salt Lake City, worked with her colleagues on cycad pollination. They found out that the male cones tend to have higher temperature in the middle of the day, and the concentration of the smell of the plants is the highest which proved toxic to the thrips, their pollinators. The cones of the male cycads were almost twelve degree Celsius higher than the ambient temperature, which chase the pollinators away from the male plants. On the other hand, compare to the male cones, the female cycads have low concentration on the smell, and they attracted most of the insects to go to their cones.

In this case, the insects go into the cones of the male cycads, and leave for female cones in the middle of the day. The insects will keep leaving from the male to the female and help them pollinate. Scientists study how the plant repels pollinators to achieve its aims to have a closer look at the relationship of plant-pollinator.

Source: http://sciencenow.sciencemag.org/cgi/content/full/2007/1004/2

Posted by Xuni Li (2)