Welcome back.

This week, guest writer and science journalist, Pragathi Ravi, connects the fungi-farming behaviors of leaf cutter ants to the sustainable agriculture and land stewardship practices of indigenous peoples in India and beyond.

Perhaps, the best method to conserve biodiversity isn’t to set land aside untouched and removed from human beings, but to live in relationship with the land and other species — something leaf cutter ants have been doing for nearly 60 million years.

Enjoy.

— Willow

As a child, I remember being fascinated by a parade of tiny red ants carrying crumbs of food, perhaps dusted off from our clothes after a meal, to their den.

They would ferry their foraged provisions through two fine lines, in a formation that rivalled military precision. This enraptured me as a five-year-old, who would spend hours in my home in India, fixated on this system that functioned like a well-oiled machine. 

A few years ago, I remember seeing a video shot in South America of another colony of ants carrying snipped pieces of leaves over tree bark, which kindled my childhood fascination. Here were a bunch of leafcutter ants, which do not directly feed on the leaves but take them back to their den to farm a fungus they consume. Again, fascinating. But as an adult now, I wanted to dig deeper into the ‘why and how’ rather than be content to watch this parade unfold. 

While humans have taken pride in heralding the beginning of modernization by pioneering farming, these pesky groups of ants have been doing it for far longer— almost 60 million years.

Scientists have dated this to the impact of the end-Cretaceous asteroid, which is believed to have wiped out non-flying dinosaurs, temporarily interrupted photosynthesis, triggered a global mass extinction, and aided the proliferation of fungi. 

Since then, certain ant species, including leafcutter ants, started farming fungus as food. In what evolved into a mutually beneficial relationship that has stood the test of time, leafcutter ants fed their fungus crop with the leaves they harvested. Interestingly, it has also been established that all of the fungi that the ants cultivate appear to have descended from a single, ancestral fungi cultivar. 

Evolutionary biologist Michael Poulson has studied these fungus-farming ants for a while now. He was trying to understand symbiotic interactions— either beneficial or antagonistic— which led him to spend over a decade teasing out the farming symbiosis that underlies the industrial-scale agriculture that the ants practice. 

I say industrial-scale because researchers have found that ants inhabit a complex society, where millions of ants perform clear-cut roles in maintaining the massive fungal chamber that supports their sustenance. 

These ants cut up fresh leaves, and they bring them back to their den containing the fungal gardens to feed the fungus.

“This is a cleaning process that reduces other microbes from entering the gardens. They then chew it to kind of a pulp, which leads to the initial mechanical breakdown of the leaf material,” Poulson adds.

They also sometimes mix this pulp with fecal fluids because the ants ingest fungus material, enzymes from the ants pass through the ant’s gut, and remain active. This primarily helps them decompose hardier plant components such as cellulose, which the ants themselves cannot digest directly. The fungi break down these plant compounds into fungal biomass, which the ants then feast upon.

“What is unique for the fungus farming ants is that you have these external fungus gardens [that take over the] decomposition of the plant biomass, so it's almost like an external gut in a way,” Poulson states.

What makes this system sustainable is that although the ants take huge amounts of leaves, this rarely kills large trees.

The vegetation regrows, making it unlikely for an entire population of a given plant species to succumb or be overrun by the ants, even if an individual plant might not make it.

“The system does not collapse, because it’s part of a balanced ecosystem,” Poulson points out. 

This isn’t unique to ants; for centuries, indigenous communities have applied similar principles of sustainability and mutual respect to forest management.

The fact that fungus cannot survive without the ants, or that the ants cannot sustain without their fungal food, is reminiscent of how communities have historically inhabited biodiverse landscapes that they have traditionally cared for. Over the years, researchers have traced how this symbiotic relationship has played out. 

One such researcher is Neema Pathak Broome, from Kalpavriksh, an India-based non-profit that monitors the implementation of conservation laws alongside supporting local communities in their efforts towards ecological sustainability and social equity. 

The culture among most countries in the Global South, Broome points out, is that of interconnectedness, reciprocity, and respect for non-human nature. This means that the indigenous communities, who have been historic custodians of undisturbed tracts of land, have long-standing traditions and customs that govern the health of the ecosystem.

“Because of these cultural norms, practices, and knowledge systems, nature has sustained along with people,” she says. 

But when colonial powers arrived to countries like India, they failed to understand these cultural nuances. They devised their own policies that relied heavily on the delimitation of wild spaces and those who inhabited them.

Subsequently, there was a loss of biodiversity and megafauna, which led the state to enact laws conserve this biodiversity and an attempt to restore the land to its prime health. 

“They never addressed the root cause [of why this] rapid decline actually happened,” says Broome.

She and other experts working with indigenous people and local communities, as well as recognition of their specific rights, refer to this approach to conservation as a “fortress model.” This is where those who have lived and taken care of the land for generations are shunned and walled off to protect pristine landscapes, often for the benefit and recreation of those whose ways of being have primarily been at the root of the degradation of nature and indigenous culture.

Currently, nearly 15% of the world’s land is protected, while the ambitious 30x30 target under the UN Convention on Biological Diversity aims to protect 30% of global land by 2030. While this looks good on paper, the ground reality is far more troubling. 

“The creation of protected area models across the globe, not just in India, but particularly in countries like Africa and Asia, has alienated not only the people, but also the conservation efforts of these communities,” Broome states.

While these conservation policies claim to be informed by a scientific outlook, they routinely ignore the traditional knowledge or science of people who have looked after the place for centuries, before the state took note of biodiversity worth protecting. 

“So many of the national parks and sanctuaries are actually built upon what used to be the traditional ways of conservation by indigenous people and local communities,” Broome says.

Like the ants, these communities have subsisted on natural forest products for centuries by selectively harvesting what they need to live.

They harvest non-timber forest products (NTFPs) such as fruits, tubers, wild vegetables, nuts, and medicinal herbs that meet basic needs and support the livelihood of these households. Here, the community selectively exploits produce in a manner that doesn’t deplete its abundance, thereby thwarting regeneration, or damaging soil fertility.

For instance, tribes in Uttarakhand in northern India practice agroforestry, by intercropping trees with food crops to enhance soil fertility. By harvesting sustainably, tribal communities ensure that forests remain intact for future generations, while simultaneously benefiting from their resources, according to reports. 

Broome notes that when she lived in a village located in the foothills of the Himalayas, she was introduced to the ways of the Mishmi community.

The Idu Mishmi people in the Indian state of Arunachal Pradesh deeply revere tigers as their elder brothers, and hunting them is against their social and cultural institutions. This belief is deeply rooted in their social identity and the reciprocal relationship that they share with nature. This is that they protect nature, and nature protects them. 

A 2023 research paper notes that “conditioning social and personal prosperity on ancestrally mandated, morally correct behavior in the forest, Idu taboos ensure that people understand that human well-being is inextricably linked to restrictive hunting.” 

As practitioners of animism, the belief that humans, animals, and plants possess a soul is common within the community.

For centuries, this has guided their outlook towards hunting and the consumption of wild meat. So for Broome, it comes as no surprise that this region has the highest concentration of tigers in the country. A Mongabay report highlighted how the Dibang landscape, where the Idu Mishmi live, harbors more tigers than any other tiger reserve. 

While scientists have discovered that tigers exist in large numbers there, policymakers and conservationists, however, fail to understand why.

“Instead of figuring out how to strengthen this [relationship], they bring in a tiger reserve,” she says, alluding to an exclusionary, top-down approach that delineates the relationship that the community has fostered with their land. 

The work that these communities put in has been overrun by the state. Broome maintains that the state’s conservation policies should strengthen the community’s relationship with nature rather than weaken it.

Ultimately, for both the ants and indigenous communities, conservation doesn’t seem to be an end goal but a consequence of their way of life.

Broome and Poulson emphasize how both the communities and colonies have historically relied on knowledge, or instinct in the case of ants, to harvest to their means and not beyond.