November 22, 2011

The Ant, the Shaman and the Scientist: Shamanic lore spurs scientific discovery in the Amazon

When he pointed to the tree trunk and said the scars were from fires set by invisible forest spirits, I had no idea this supernatural observation would lead to a new discovery for natural science.  Mariano, the eldest shaman (who has since passed away) of the Matsigenka village of Yomibato in Manu National Park, Peru, had first showed me the curious clearings in the forest that form around clumps of Cordia nodosa, a bristly tropical shrub related to borage (Borago officinalis).  Both the Matsigenka people and tropical ecologists recognize the special relationship that exists between Cordia and ants of the genus Myrmelachista: the Matsigenka word for the plant is matiagiroki, which means “ant shrub.”

Maximo Vicente, Mariano's grandson, standing by a 
swollen, scarred trunk near a Cordia patch.
For scientists, the clearings in the forest understory around patches of Cordia are caused by a mutualistic relationship with the ants.  Cordia plants provide the ant colony with hollow branch nodes for nesting and bristly corridors along twigs and leaves for protection, while the ants use their strong mandibles and acidic secretions to clear away competing vegetation.  Local Quechua-speaking colonists refer to the clearings as “Devil’s gardens” (supay chacra).  For the Matsigenka, these clearings are the work of spirits known as Sangariite, which means ‘Pure’ or ‘Invisible Ones’.  Matsigenka shamans like Mariano come to these spirit clearings and consume powerful narcotics and hallucinogens such as tobacco paste, ayahuasca (Banisteriopsis), or the Datura-like toĆ© (Brugmansia).[1]