In sports, sometimes a player has to take one for the team. The same appears to be true in the plant world, where reduced individual growth can benefit the broader community.
The findings from the University of Michigan's Paul Glaum and André Kessler of Cornell University help explain the persistence of some plant communities when theory predicts they should go extinct. The work was published Dec. 11, 2017 in Nature Communications.
"We looked at how chemical defense cues from plants, meant to deter herbivores, can also deter pollinators," said Glaum, a doctoral student in the U-M Department of Ecology and Evolutionary Biology. "The surprising model result is that while this can lead to fitness losses for individuals, the population effects can be positive for pollinators and plants under some circumstances."
Many plants, including the wild tomato species used in this study, produce chemical compounds to repel insect pests and other hungry herbivores. But those same chemical defenses can reduce the number of visits to the plant by pollinators such as bees, resulting in less pollination of individual plants and decreased growth.
"Biologists have puzzled over how such a costly defense mechanism can be maintained in these plant populations," Glaum said. "How would a plant population with such a strategy persist?"
Glaum and Kessler developed a computer model showing that decreased growth of individual plants can benefit overall populations and community resilience by indirectly controlling herbivore population growth. The results introduce mechanisms of persistence into communities previously found to be prone to extinction in theoretical models. Glaum works in the lab of Professor John Vandermeer.
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