Morning glories experience 96% drop in adaptation due to pollinator pressure, study finds

A study by the University of Michigan published on July 9, 2026, reveals that morning glories are experiencing a 96% decline in their rate of adaptation as they evolve to attract pollinators in the face of climate change and declining pollinator populations. This research highlights the challenges plants face in adapting to a warming climate.

Impact of Pollinator Pressure on Plant Evolution

Researchers observed that the need to attract pollinators with larger flowers has taken precedence over the evolutionary advantage of earlier flowering times in morning glories. According to Regina Baucom, a professor in the U-M Department of Ecology and Evolutionary Biology, "Because pollinator pressure strongly favors larger flowers, that linkage may limit how efficiently the population can respond to other selective pressures." This shift in adaptation priorities could have significant implications for agricultural practices.

The study indicates that despite sufficient genetic variation in newer plant populations, the morning glories are increasingly locked into a trajectory that favors pollinator attraction over climate adaptation. Baucom states, "The plant isn't running out of evolutionary fuel—it's increasingly locked into a trajectory that favors pollinator attraction, potentially at the expense of climate adaptation."

Human-Caused Changes and Their Effects

Lead researcher Sasha Bishop, along with collaborators including John Stinchcombe from the University of Toronto, examined the impact of human-caused global change on morning glories. Changes in habitat due to urban development and agricultural practices, including pesticide and herbicide use, have led to a significant decline in pollinator populations. Bishop notes, "Instead of evolving, there are all these wild populations that are dying off, declining or going through genetic bottlenecks." This disconnect between theoretical adaptation rates and observed declines poses serious questions about plant resilience.

Research Methodology and Findings

The researchers conducted a resurrection experiment with morning glory seeds collected from wild populations at two different points in time, nine years apart. They focused on traits influenced by climate change and pollinators, recording data such as flowering time, flower size, and nectar sugar levels.

Using a statistical measure called R, which predicts population adaptation, they found that over the nine-year period, the adaptation rate for morning glories plummeted from 76% to 9% of what was expected without trait covariance. This indicates a significant limitation in the plants' ability to adapt to environmental changes. Bishop emphasizes that "the implication in my mind is that pollinator decline, or the lack of pollination and selective drive to attract pollinators, is making these plants potentially less able to adapt to climatic shifts."

• 96% drop in adaptation rate observed
• Study published in Evolution Letters
• Research led by Sasha Bishop
• Focus on morning glories as an agricultural weed
• Link between flower size and flowering time identified