Sci Sat: Ants: The unlikely inheritors of the dinosaurs' world
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Ants: The unlikely inheritors of the dinosaurs' world

A new study in Science reveals how the dinosaur-killing asteroid inadvertently paved the way for ant agriculture.

Key takeaways:

• Fungus-farming ants arose approximately 66 million years ago, coinciding with the Chicxulub asteroid impact that wiped out the dinosaurs.

• The asteroid's aftermath created ideal conditions for fungi to proliferate, providing ample food sources for ants.

• Ants' pre-existing relationship with fungi allowed them to capitalize on this abundance, leading to the evolution of ant agriculture.

• "Higher agriculture," where ants cultivate specialized fungi, evolved later, around 27 million years ago, likely driven by climate change and the expansion of grasslands.

The research:

A team led by Smithsonian entomologist Ted Schultz analyzed genetic data from 475 fungal species and 276 ant species. By constructing evolutionary trees for both groups, they pinpointed the origins of ant agriculture to the aftermath of the Chicxulub impact.

Quotes:

• "Extinction events can be huge disasters for most organisms, but it can actually be positive for others. At the end of Cretaceous, dinosaurs did not do very well, but fungi experienced a heyday." - Ted Schultz, Smithsonian Institution

• “Ants have been practicing agriculture and fungus farming for much longer than humans have existed. We could probably learn something from the agricultural success of these ants over the past 66 million years." - Ted Schultz, Smithsonian Institution

• "I think the paper makes a solid case... In a world where photosynthesis was reduced... 'detritivores ruled,' and ants that were already feeding on fungus had an unexpected advantage that bloomed into a deeper form of interaction." - Jonathan Shik, University of Copenhagen entomologist

The impact aftermath:

The asteroid impact triggered widespread devastation, but it also created opportunities for opportunistic species like fungi. With reduced sunlight hindering plant growth, decomposers like fungi flourished, feeding on the dead plant matter. This abundance of fungi provided a readily available food source for ants, many of whom already had a pre-existing relationship with fungi.

The rise of ant agriculture:

This confluence of factors – the abundance of fungi, the pre-existing ant-fungus relationship, and the decimation of other lifeforms – created a perfect storm for the evolution of ant agriculture. Ants began cultivating fungi, providing them with protection and ensuring a stable food supply for their colonies.

Higher agriculture:

As ecosystems recovered and climates changed, ant agriculture continued to evolve. Around 27 million years ago, a cooling climate led to the expansion of grasslands. This change drove some ants to develop "higher agriculture," cultivating specialized, domesticated fungi that could thrive in drier conditions. These ants, like the leafcutter ants we see today, actively provide their fungal gardens with fresh vegetation, much like human farmers.

Significance:

This study illuminates a fascinating example of how life can rebound from catastrophic events. It highlights the resilience of nature and the surprising ways in which even seemingly insignificant creatures, like ants, can play a vital role in shaping our planet's history. Furthermore, studying these ancient farmers could provide valuable insights for improving our own agricultural practices.