According to Whiteley, a director of Conservation of Butterflies in SA, the spectacle is an annual event, but that the clouds of Belenois aurota, commonly known as brown veined white butterflies, do not always follow exactly the same route.
"They start hatching along the entire coast from Cape Town towards Namibia, then migrate inland in a north-easterly direction."
The cycle of life
Whiteley says that the initial batch of butterflies are joined by more and more along their migratory route, over the Eastern Cape, before reaching Gauteng.
The butterflies then head toward Mozambique before crossing the sea to Madagascar.
"As they are going further north, some die and more join. Eventually, there are massive clouds of butterflies, reaching up to a kilometre into the air."
Along the route, the female butterflies lay eggs, which begin the life cycle of the next generation.
Migration dependent on weather
The timing of the migration is dependent on weather conditions, but usually runs from late November to mid-February. The brown veined white butterflies are often joined by other butterflies of the same Pieridae family, which have shades of yellow or orange in their colouration.
The butterflies travel from sunrise to dusk and need to replenish themselves with nectar every 20 minutes or risk dying from dehydration. They favour long grass and are particularly attracted to grass nectar, Whiteley says.
The butterflies roost overnight, and it is possible to tell whether a butterfly is awake or asleep by looking at their feelers.
"If the feelers are touching, then they are sleeping."
Whiteley is working towards establishing the Gauteng Butterfly Sanctuary, which is expected to open in December.
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