The catastrophe that eradicated the dinosaurs had some unexpected positive consequences. The dim environment following the meteor impact roughly 66 million years ago enabled the proliferation of fungi that thrive on organic materials, which were plentiful as flora and fauna succumbed in large numbers.
This created an ideal scenario for the precursor of a specific group of ants to begin nurturing these microorganisms, according to research published on October 3 in the journal Science
The timeline was established through analysis of ultraconserved elements (UCEs) in the genomes of 475 species of fungi managed by ants collected from various regions in the Americas. These UCEs represent sequences that persist within the genome throughout a group's evolutionary history, originating from its earliest ancestors.
“In this study, we focused on regions adjacent to these elements. They reveal the most current variations among species and enable us to delineate a fairly precise evolutionary pathway,” remarks Pepijn Wilhelmus Kooij, a researcher at IB-UNESP.
By employing this technique, the research identified the near-concurrent appearance of two unique fungal lineages from a common ancestor of today's leafcutter ants, part of a group called Attini, around 66 million years ago.
Experts on the mutualistic bond between fungi and ants have long held that the inception of this connection marks the origin of agriculture, occurring tens of millions of years before humans began domesticating plants merely 12,000 years ago.
The study further unveiled the appearance of an ancestor of coral fungi, another category that began to be nurtured by ants 21 million years prior. This fungus is named due to its structure resembling miniature colonies of coral.
An image enlarged a thousand times displays the nutritive vesicles (gongylids) produced by the fungus Leucoagaricus gongylophorus, nurtured by the lemon leafcutter (Atta sexdens). Credit: André Rodrigues/IB-UNESP
Mutualism
The findings bolster the theory that fungi had likely undergone preparatory adaptations before being tended to by ants. The researchers suggest that the ancestor of the leafcutter ant group possibly existed in close association with fungi, either dwelling alongside them or intermittently gathering them for nourishment or their byproducts.
Presently, four distinct ant groups cultivate four varieties of fungus. In certain instances, these insects even modify the growth of the cultivated fungi to enhance nutrient availability.
“In laboratory conditions, the fungi develop the expected hyphae form. However, within the colony, one particular type of hyphae becomes enlarged and forms shapes similar to grape clusters, rich in sugars. The precise mechanism by which the ants achieve this remains unknown,” Kooij explains.
According to Mauricio Bacci Junior, professor at IB-UNESP and co-author of the study, the origin of fungal cultivation likely suggests an adaptation to nutritional scarcity experienced by the ants during that time period.
With a surplus of fungi blossoming across what are now the Americas, and with diminishing food options, those fungi that shared a symbiotic relationship with ants became significantly more advantageous when nurtured.
“To sustain itself, the fungus breaks down organic matter transported by the ants. In return, the ant ingests elements synthesized by the fungus that are unattainable through other means. It's as if the fungus serves as the insect's external digestive system,” states the researcher, who is also the deputy director of the Center for Research on Biodiversity Dynamics and Climate Change (CBioClima), a part of the Research, Innovation, and Dissemination Centers (RIDCs).
This incident undoubtedly contributed to the variety of fungi, which became more proficient at generating sustenance for the ants and decomposing organic materials.
The enzymes produced by these fungi now under ant cultivation are currently being investigated for their biotechnological applications in degrading not only organic substances but also various other materials, including plastics.
More information:
Ted R. Schultz et al, l, The coevolution of fungus-ant agricult, Science (2024). DOI: 10.1126/science.adn7179
How the Asteroid that Killed the Dinosaurs Paved the Way for Ant Agriculture Innovation
In a remarkable twist of fate, it appears that the catastrophic asteroid impact 66 million years ago, which led to the extinction of dinosaurs, also set the stage for a groundbreaking evolutionary leap—ant agriculture. According to recent studies, the environmental upheaval caused by this event not only wiped out a significant portion of life on Earth but also created opportunities for some species to adapt in unexpected ways.
After the asteroid struck, the subsequent “nuclear winter” conditions resulted in a drastic reduction in sunlight, severely impacting plant life. This led ants to innovate by cultivating fungi, essentially becoming the Earth's first agriculturalists. As the environment changed and resources became scarce, these ants began to farm fungi, establishing a symbiotic relationship that would thrive in the new ecological landscape [1[1[1[1][2[2[2[2].
This evolutionary strategy not only ensured the survival of these industrious insects but also paved the way for the complex ecosystems we observe today. By leveraging the destruction around them, ants demonstrated resilience and adaptability, traits that are crucial for survival in dynamic environments [3[3[3[3].
As we reflect on this fascinating intersection of destruction and innovation, it raises an intriguing question: Can periods of significant adversity truly lead to advancements in survival strategies, not just for ants but for all species? How do you think our own challenges today might spur new forms of innovation in nature?