For the first time, ants were observed using the homes of pests known as coffee berry borers to rear their own young
Study: Indirect niche construction: A coffee pest facilitates its own ant natural enemies (DOI: 10.1002/ecy.70463)
Ants are known allies in the fight against coffee pests known as coffee berry borers. Now, a discovery made by Jonathan "Jonno" Morris while he was a University of Michigan graduate student has revealed there may be a new dimension to this protection.
Ecologists have known that large ants eat the berry borers and stymy the pests' efforts to colonize coffee plants. And small ants can root the borers out of the homes they make for themselves in coffee fruits. Morris has, for the first time, observed that small ant species can then use the habitats in the fruits for their own reproduction.
"In terms of pest control, this is primarily a good thing because it's benefiting the ants in terms of their populations and fitness. The ants gain this reproductive benefit that's originally created by the coffee pest. And this might actually help to maintain more diverse ant communities directly on the coffee plants," said Morris, who made this discovery as a graduate student at the U-M School for Environment and Sustainability, or SEAS.
He is now a postdoctoral researcher with the Universidad Nacional Autónoma de México, or UNAM (the National Autonomous University of Mexico), in Mexico City, and an affiliated U-M researcher continuing his work with Ivette Perfecto, a SEAS professor. Working with John Vandermeer in the Department of Ecology and Evolutionary Biology, Perfecto has been studying agricultural ecosystems on coffee farms in Central America for 25 years with federal support from the U.S. National Science Foundation.
It was in 2016 that Morris started this project, albeit somewhat unknowingly, while working at a research station established by Perfecto and Vandermeer on a farm in Chiapas, Mexico. While conducting research for a different project, he had collected samples of coffee berries that had, at one point, been infiltrated by the borers, then evicted by ants.
"I had all these ants in vials that I had found nesting in coffee fruits and told myself, 'Maybe I'll do something with this at some point,'" Morris said. "Then, years later, I got to thinking about it and, as far as I know, this is the first time anyone's documented or reported the ants taking advantage of the niche construction by the berry borer and using it to reproduce themselves."
So, in 2025, Morris worked with research technicians to go back into the field to gather more evidence of this behavior and take the first photographs of it. The finding is published in The Scientific Naturalist section of the journal Ecology.
Beyond its ecological and pest-control implications, the study also underscores the importance of being in nature, observing what it's doing and reflecting on that-especially in the age of data science and artificial intelligence, Morris said.
"Right now, there's an emphasis from funders on AI and big data, but before people had all these fancy tools, they were going out into nature and making observations and discovering patterns. Think about Charles Darwin and Alexander von Humboldt," he said. "But if it wasn't for having funding for basic science and doing these types of observations, I wouldn't be sitting here talking about them."
This work was supported by UNAM through its Postdoctoral Scholarship Program.
