The witchetty grub is the larvae of Xyleutes biarpiti which is a large grey moth of the Cossidae family. These grubs are most often found in the roots of just one plant, the witchetty bush (Acacia kempeana) which is relatively common in Central Australia, but they can also be found in the roots of some river red gums.
There are 270 different Aboriginal languages and 600 to 700 dialects in Australia, this has caused different spellings. The name witchetty grub (also spelled witchety or witjuti) is derived from the Pitjantjatjara name for Acacia kempeana, but it has now been loosely applied to many edible grubs across Australia.
The grubs can be harvested at almost any time of the year, but the colder months usually offer the best time for harvesting and in an exceptional season up to fifty grubs can be taken from a single tree. The presence of witchetty grubs in the roots of the witchetty bush is usually noted by slight cracks in the soil indicating swelling of the roots. The indigenous peoples of Central Australia take great care to look after the witchetty bush, never digging up more than three of the bush’s shallow roots at any one time, each such root will yield between one and two grubs.
The main threat to the continued existence of the witchetty grub is loss of habitat through heavy grazing by introduced cattle: overgrazing in extended drought periods will kill the witchetty bush. Very hot summer wild fires will also kill these bushes.
This food is very important to the indigenous people of Central Australia – especially women and children – as it is extremely rich in easily assimilated proteins and fats (it has 38% protein and nearly 40% fat). The witchetty grub is often eaten raw, especially if it is damaged when being removed from the host tree’s roots. More usually, the grubs are collected and then lightly roasted on coals for less than one minute, then eaten (the head of the grub is never eaten). When roasted, the taste is reminiscent of egg yolk, pop corn and almonds. Whilst the witchetty grub is found in other parts of Australia, it is especially important in Central Australia where there are very few other sources of rich oils and proteins. But over the last 200 years, entomophagy among Australian Aborigines has decreased because of the increasing adoption of European diets, changed social structures and changes in demography.
Witchetty grubs feature very prominently in indigenous mythology with many dreamtime stories relating to them and each of the seven language groups assigns to an individual the witchetty grub as a totemic item to be protected.