Reduction in individual plant growth helps boost community resilience: study

CHICAGO, Dec. 11 (Xinhua) -- U.S. researchers found that while chemical defense cues from plants meant to deter herbivores can also deter pollinators, thus leading to fitness losses for individual plants, the population effects can be positive for pollinators and plants under some circumstances.

Previous modeling studies have looked at the direct effects of herbivory on a three-species community: flowering plant, pollinator and herbivore, and predicted extinctions because growing herbivore populations would reduce the number of plants, limiting resources available to pollinators.

But the researchers at the University of Michigan (UM) and Cornell University developed a computer model showing that decreased growth of individual plants can benefit overall populations and community resilience by indirectly controlling herbivore population growth, and then reached a different conclusion when they included herbivore-induced pollinator limitation (HIPL) in their model.

The modeling study suggests that the herbivore-induced release of protective chemical compounds limits population growth of both the pollinator and the flowering plant, thereby temporarily and indirectly restricting the growth of herbivore populations and preventing extinction.

The researchers measured both the release of herbivore-induced volatile organic compounds (HI-VOCs) by the wild tomato plants and pollinator visits at different levels of herbivory to determine how bee pollination changes as a function of the amount of herbivory experienced by a plant.

In the field, herbivory of the tomato plants was found to significantly lower pollinator visits due to the release of HI-VOCs.

However, the modeling study showed that the mutually beneficial relationship between the flowering tomato plant and its bee pollinators, as well as the overall system, can persist through higher rates of herbivory than researchers had previously believed.

The findings are scheduled for publication on Dec. 11 in Nature Communications. Enditem