Thursday, March 10, 2016

Africa’s poison arrow beetles are key in traditional hunting method

Humans started hunting with bows and arrows tens of thousands of years ago. Then, at some point, we realized that the arrows were even more effective at bringing down large game if tainted with poison. There were plenty of plant extracts that served as sources for deadly chemicals, such as curare, used by native people in the Orinoco Basin of South America. And some Amazonian hunters discovered that brightly colored poison dart (or poison arrow)frogs could also be the source of useful toxins.

But budding mystery novelists shouldn’t overlook other poison sources, such as the Bushman poison arrow beetle (Diamphidia nigroornata) of southern Africa. For the last couple of centuries, anthropologists have been recording how the San people of the region use the beetle and local plants to create poisons for their arrows. Now Caroline Chaboo of the University of Kansas in Lawrence and colleagues gone through those past records and visited with some of the last San hunters who hunt in traditional methods to document a fading practice. Their new study appears February 1 in ZooKeys.

The San people are traditionally hunter-gatherers, and there are about 113,000 living in Angola, Botswana, Namibia, South Africa, Zambia and Zimbabwe. Not all San groups use poison-tipped arrows, the researchers found, but those that do limit their use for when hunting large game, such as eland, elephant, wildebeest or lion, hunting smaller animals with traps and snares. And it is the Ju|'hoan San of northeast Namibia, one of the largest San groups, that get their arrow poison from beetles.

The Ju|'hoansi are also the only San group that is still allowed to subsistence hunt using traditional methods, Chaboo and her colleagues write. And some still hunt with poisoned arrows and pass down that practice to the younger generation. In many other San groups, the knowledge has been lost because people have been removed from traditional lands or hunting has been made illegal.

The poison doesn’t come from grown beetles but from beetle larvae. The larvae grow in the dirt surrounding Commiphora plants (a genus that includes frankincense and myrhh) that the adult beetles feed on. Hunters keep track of where the plants grow so they know where to find beetles in the two months when the insects are in their larval stage. A hunter digs up beetle cocoons and returns home. There, he breaks open the cocoon and removes the larva, discarding any pupae or adults. He rubs the skin of the larva to break it open, then squirts the tissue into a mortar made of an old giraffe or kudu knuckle bone. When he has the tissue from 10 larvae, he mixes it with saliva and a roasted bean of a Bobgunnia madagascariensis tree. The hunter then applies the mixture with a twig to the sinew that attaches an arrow to its shaft and allows it to air dry.

The actual poison in the mixture is diamphotoxin, and it causes calcium ions to rush into cells. Red blood cells inside a poisoned animal rupture, and the animal will experience convulsions, paralysis and then death. This makes killing big game much easier, since a hunter just has to nick the animal instead of make a killing blow.

And — here’s where mystery writers should take note — the poisoned arrows are not only used in hunting wild game; they are also “the most common weapon in family quarrels, suicides, homicides and warfare,” the research team writes. “The victim can die within one day if the wounded limb is not amputated.”

As more and more people leave (or are forced to leave) traditional lifestyles, Chaboo and her colleagues note, we are losing the knowledge acquired over thousands of years and may miss out on opportunities to understand important steps in the evolution of humankind. But, perhaps more importantly, we may also be missing out on clues to knowledge that could also be beneficial in the modern world, as medicines, pesticides and other useful chemicals have been derived from natural poisons and toxins. Perhaps a poison that once laced an arrow could lead to another one of these discoveries.

Zielinski, Sarah2016. “Africa’s poison arrow beetles are key in traditional hunting method”. Science News. Posted: February 10, 2016. Available online:

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