Tradeoff between resistance induced by volatile communication and over-topping vertical growth.

Plants commonly respond to reliable cues about herbivores by inducing greater defenses. Defenses are assumed to incur costs for plants when they are not needed. Sagebrush responds to volatile cues from experimentally clipped neighbors to induce resistance against chewing herbivores. Rather than experiencing costs, sagebrush seedlings that responded to dishonest cues were previously found to have increased survival and established plants that responded produced more inflorescences and new lateral branches. Here I report that young sagebrush plants that responded to cues added less vertical growth than controls that were not presented with volatile cues. This tradeoff between induced resistance and vertical, overtopping growth may allow agronomists to increase defense without sacrificing desirable traits. Overtopping growth is often beneficial for wild plants but often detrimental in agriculture.