When the summer rains come to the eastern parts of Botswana, people travel into the region from hours away, and head into the mopane woodlands in search of the ‘diamonds of Bobirwa’. The caterpillars of the region’s distinctive emperor butterfly break from their eggs in time with the rains, and explode in a feeding frenzy on the leaves of the mopane trees. That’s when people gather them up by the bucket-load, and take them back home either to use as food for themselves, or to sell at the local market.
For generations, people have dried the caterpillars, and either cooked them into a relish, or ground them down to powder and mixed this into porridge or yoghurt. Some people even travel from as far away as South Africa, coming here when the caterpillars flush to buy the dried insects for use in cattle feed: they mix the powdered mopane ‘worms’ into sorghum meal with a bit of salt to feed to their livestock.