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What not to eat

- Donald McCallum

Although eating insects might stave off starvation in a survival situation, chowing down on foam grasshoppers or red-yellow-black bugs could be fatal.

Termites and Mopane worms pizza. © Lauren Mulligan  |

Many people find the idea of eating bugs repulsive. The half worm found after biting an apple is seldom celebrated as extra nutrition – rather it may leave a person horrified and nauseated. What a contrast between a Western attitude to consuming bugs and that of many cultures, particularly in tropical areas where, at certain times of the year, insects form a very important part of the diet. The list of species of arthropods eaten worldwide is now around 1 900, an impressive number. 

In a survival situation, eating bugs could save one from starvation, but what should one avoid? With so many different species eaten, it is not a simple matter knowing which not to consume. Scorpions, bees and wasps have venom yet scorpions are eaten in Thailand and bees in China. Some wasps are said to be tasty. The UK Independent of 16 August 2018 reports a lost hiker in the pacific northwest of the USA who survived a week eating bees and berries. Clearly venomous and inedible are not linked! 

Another way to decide which bugs to avoid could be those with warning colouration – red and yellow often combined with black as a contrast. This colour combination warning would save you from eating blister beetles, which contain a toxin, cantharidin, which can be fatal. 

Foam grasshoppers resemble edible locusts in shape and size but often have brightly coloured bodies, or red wings which they open when threatened. Deaths have been reported from eating some species. Regrettably, avoiding warning colouration would deny you Mopane caterpillars, which have red and yellow markings and look quite intimidating. 

But not only are they safe to eat, they are very nutritious with a high protein content.

Avoiding bugs from plants that you suspect or know are toxic is wise. Foam grasshoppers and the caterpillars of the African Monarch butterfly are poisonous as a result of storing the poisons from milkweeds such as Gomphocarpus. Pest species of cockroach are known to eat almost anything, and could well contain pathogens, however, cockroaches that live in the veld and woodland would be fine to eat – they have a better diet! 

Given that it is difficult to decide which arthropods should not be eaten it may be easier to know which are likely to be safe to eat. Termites would be one such insect. They are widely distributed, relatively easy to find and present in large numbers. With little effort many can be caught using a piece of grass or by throwing a piece of material over a place where flying ants are emerging. Dried termites have from 25% to over 50% protein and around 2% fat – not at all bad for free food! 

Crickets are probably also a good choice as a number of species are eaten in different parts of the world, and not too difficult to recognise. Locusts are often abundant, but care needs to be taken to distinguish them from foam grasshoppers. A number of different emperor moth caterpillars are eaten in various parts of Africa, and many of these are found in large numbers on their host plants. In a pinch, I would risk eating any caterpillars in the baby finger or larger size range. 

  • Donald McCallum is a botanist in the C.E. Moss Herbarium in the Wits Life Sciences Museum, School of Animal, Plant and Environmental Sciences (APES). In addition to his work with plants, he has a strong interest in informal teaching through displays, gardens and exhibitions. His interest in insects as a food source developed from having edible insects to taste at the annual Yebo Gogga Yebo amaBlomo exhibition at Wits.
  • This article first appeared in Curiosity, a research magazine produced by Wits Communications and the Research Office.
  • Read more in the sixth issue, themed: #HungerGames where our researchers and academics unpack the latest research on food security, food science, food politics and governance, nutrition and food-related issues such as obesity, diets, breastfeeding, and body image.