Biotic interaction III

Question	Answer
What are the three reasons plants still exist even though herbivores are so abundant and efficient?	1. Bottom up control of herbivores by plants 2. Top down control of herbivores by predators 3. Herbivore populations can't track plant resource abundance.
What are volotile organic compounds and how are they used?	VOCs are released by herbivory and act to reduce it. It can also be released to reduce the rate of oviposition by herbivorous insects. These VOCs are released at night when oviposition rates are high and are not released during the day to decrease damage to the plant and to conserve energy.
Give an example of top-down control of herbivory by predators.	Plants can identify specific herbivores and release chemical attractants for predators that prey specifically on that herbivore (e.g. caterpillar and wasp)
What is one way plants make it so that herbivores can't track resource availability?	Plants may release massive amounts of seeds to make sure that herbivores will be saturated and some seeds will grow. This happens in cycles of a few years. The year of massive seed release is called a masting year.
How are prey populations controlled?	1. by predators if the range is small enough. Extra prey are killed before they can reproduce, but when prey populations fall, so do predators, but the populations lag behind. 2. In broad areas, environmental and predatorial regulation.

Resource summary

	Created by Shareef Akbari almost 8 years ago