How San hunters use beetles to poison their arrows

San ('bushman') hunters use lightly constructed bows and arrows in their hunting which means that the injury inflicted by the arrow is usually insufficient to subdue large prey unless it is supplemented by a poison that has been applied to the arrow. A variety of poisons have been used by the various groups of hunters. Some use plant-derived substances or toxins derived from poisonous snakes. However, in the northern Kalahari, the most commonly used poisonous substance for arrows is that derived from the larva and pupae of chrysomelid beetles in the genus Diamphidia.


Digging up cocoons of Diamphidia beetles in the vicinity of their host plant Commiphora sp. The cocoons are usually buried 0.5 -1 m below ground surface.	Each cocoon usually contains a larva in an arrested stage of development prior to pupation. Larvae can stay in this dormant stage for several years.

A San hunter squeezing the haemolymph of a beetle larva on to an arrow. Up to 10 larvae may be applied to one arrow. The poison is applied to the foreshaft behind the point and not to the point itself, evidently to avoid accidental poisoning to the hunter from being scratched by the arrow point. The poison is a protein and becomes less potent with time but generally can retain its toxicity for up to a year.	A drop of haemolymph of the Diamphidia vittatipennis larva is squeezed from the larva onto the arrow shaft.

The adult of Diamphidia vittatipennis. Read up more about its life cycle.

Two main species of Diamphidia are used namely Diamphidia nigroornata (host plant Commiphora angolensis) and Diamphidia vittatipennis (host plant Commiphora africana). In addition, larvae of the chrysomelid beetle Polyclada flexuosa (host plant Sclerocarya caffra) can also be used as a toxin. Each of these three species is also parasitised by carabid beetles in the genus Lebistina. The Lebistina larvae, by attaching themselves to full-grown Diamphidia and Polyclada larvae, remain with them when they make their cocoon. Inside the cocoon, they feed on blood and soft parts of the chrysomeld larvae, eventually killing them. The Lebistina larvae are also toxic, in fact the San hunters evidently find them more toxic than the chrysomelid larvae and favour these parasitic larvae for their arrows.

There are three main ways in which the poison may be applied to the arrows:

Squeezing the contents of larvae/pupae directly on to the arrows (see above photos). This might be followed by drying the arrows over a fire.
Making a mixture of beetle larvae/pupae plus plant juice plus spit and then applying it to the arrows. The plant juice acts as an adhesive.
Drying the larvae/pupae in the sun, grinding them into powder and then mixing the powder with plant juices. This mixture is then applied to the arrows.

After shooting an animal with an arrow, the hunters then follow its spoor until the poison subdues it which can be within a few hours but which can take 4-5 days in the case of large prey such as giraffe. A wounded animal can evidently travel 40-70 miles (64-112 km) before slowing down and finally falling down dead. Noli (1993) comments on the fact that this system of hunting animals is very time consuming and in fact would be much more efficient if more powerful bows with more injuring arrows were used. There are various reasons why they might not have adopted more powerful bows including the possibility that hunting is more than just about survival but also about a culture and sport with rules and status.

It is interesting that the toxin from these beetle larvae/pupae (called diamphidia toxin) in non-toxic to mammals by ingestion and is only toxic after it enters the blood stream. This is puzzling because it then raises the question as to how this toxin provides protection to the beetle larva from predators and parasitoids. Perhaps this non-toxicity by ingestion does not apply to non-mammals.

References

Koch, C. 1958. Preliminary notes on the coleopterological aspect of the arrow poison of the bushmen. Pamphlet of the South African Biological Society 20: 49-54.
Noli, H.D. 1993. A Technical Investigation into the Material Evidence for Archery in the Archaeological and Ethnographical Record in Southern Africa. Unpublished Ph.D. thesis, University of Cape Town, 252 pages.
Shaw, E.M., Woolley, P.L. & Rae, F.A. 1963. Bushman arrow poisons. Cimbebasia 7(2): 2-41.
Woollard, J.M.R., Fuhrman, F.A. & Mosher, H.S. 1984. The bushman arrow toxin, diamphidia toxin: isolation from pupae of Diamphidia nigro-ornata. Toxicon 22: 937-946.

Text and photographs by Hamish Robertson