Meet the world’s oldest farmers

Jared Otieno harvests termites from an ant hill at Kotetni Village in Kisumu. Scientific research and evidence shows that insects and termites display behaviours that make them effective fungiculturists. PHOTO | TONNY OMONDI | NATION MEDIA GROUP

What you need to know:

  • Scientists had previously used DNA from modern termites to estimate the origin of termite ‘fungus farming’ behaviour back to at least 25 to 30 million years ago.
  • Worker fungi and ants forage on wood, leaves, and grasses, which pass undigested through their bodies and come out as dropping for the fungi to grow on.
  • The insects also decompose and return nutrients underground.
  • The research is part of an ongoing study focused on the evolution of a poorly known portion of the Great Rift Valley known as the Rukwa Rift, in Tanzania, which has produced an array of unexpected geologic and palaeontologic discoveries in the past few years.

Years before man started farming, insects were doing it, feeding themselves to stay healthy, according to researchers who have discovered the oldest fossil evidence of agriculture.

The team, led by Australia’s James Cook University’s Associate Professor Eric Roberts, discovered the oldest known example of fungus gardens within fossil termite nests from the Great Rift Valley of Africa, which runs through Kenya, in 25 million year-old sediments.

Prof Roberts said that scientists had previously used DNA from modern termites to estimate the origin of termite ‘fungus farming’ behaviour back to at least 25 to 30 million years ago.

However, the new research published this week has now confirmed using the new trace fossil evidence from Tanzania, allowing researchers to more accurately characterise the timing and evolution of this behaviour, something thought to have significantly modified the environment and landscape.

Some 330 species of world termites farm fungi. Workers forage on wood, leaves, and grasses, which pass undigested through their bodies and come out as dropping for the fungi to grow on.

Scientific evidence shows that the insects display other behaviours that make them effective fungiculturists.

For instance, worker termites normally patrol the garden, performing endless chemical inspections with their antennae.

PARRALELS WITH HUMAN AGRICULTURAL SYSTEM

Before they add new garden substrate, they lick it to get rid of unwanted spores with their mandibles and take them to a dump chamber, used specifically to stash the unneeded material.

If the fungus pathogen germinates, the termite workers, which always share duties, again weed the garden and remove the substrate that contains the pathogen.

According to scientists, the parallels with the human agricultural system are apparent.

The insects cultivate fungi within certain genera, and can switch the type that they grow.

A leaf cutter ant. According to James Cook University’s Associate Professor Eric Roberts, scientists had previously used DNA from modern termites to estimate the origin of termite ‘fungus farming’ behaviour back to at least 25 to 30 million years ago. FILE PHOTO | NATION MEDIA GROUP

They protect their gardens from pathogens and remove undesirable organisms such as nematodes by constant patrolling and weeding, just as a crop farmer does.

Furthermore, evidence has shown that they use an antibiotic to suppress pathogens, just like human beings use pesticides and insecticides to get rid of weeds and pests.

Study co-author Prof Duur Aanen from Wageningen University in Netherlands said that the transition to agriculture dramatically increased the range of possible habitats for both the fungus-growing termites and their domesticated fungi, very much like humans and their domesticated crops and livestock, tens of millions of years later.

While the cradle of termite agriculture presumably was in an African rainforest, the transition to fungi-culture helped the termites to disperse to less favourable dry savannas and also out-of-Africa migrations into Asia.

INSECTS ARE MAJOR RECYCLERS

Prof Roberts added, “The phenomenon might have been triggered by the initial development of the Great Rift Valley in this part of eastern Africa, and the dramatic transformation of the landscape around this time.”

“This discovery pushes back the beginning of the termite-fungus symbiotic relationship to at least 31 million years ago,” said Paul Filmer, programme director in the National Science Foundation (NSF)’s Directorate for Geosciences, which funded the research.

“Since some 90 per cent of the wood in the dry environment studied is digested by termites, understanding the development of this symbiotic relationship is important to our knowledge of the history of carbon cycling in these forests,” he said.

The research is part of an ongoing study focused on the evolution of a poorly known portion of the Great Rift Valley known as the Rukwa Rift, in Tanzania, which has produced an array of unexpected geologic and palaeontologic discoveries in the past few years.

Besides termites, other insects that farm are various kinds of ants, and beetles, using similar techniques like termites.

The insects, according to scientists, play an extremely important role in the ecology of an area where they are.

First, the insects are major recyclers as they decompose and return nutrients underground.

They further excavate deep into the earth and improve soil quality by introducing organic material and nutrient-rich waste products.

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Science Daily and internet sources.