The larva feeds especially on Amaranthaceae. I found numerous eggs and caterpillars in Gran Canaria exclusively on Amaranthus deflexus on verges and walls. These caterpillars refused Malva and Bituminaria bituminosa (Fabaceae).
The larvae probably feed also on Chenopodiaceae which are related to Amaranthaceae.
Zizeeria knysna inhabits coastlines, rocky slopes, ruderal terrain, ravines, walls, gardens and roadsides. Most habitats are anthropogenic.
In the Canary Islands and North Africa, all year round. I found caterpillars, eggs and butterflies in Gran Canaria and La Gomera quite numerous around Christmas time. In Southern Spain, from spring to autumn, singly probably also in winter.
Zizeeria knysna is locally endangered due to overbuilding and agricultural intensification.
Zizeeria knysna occurs in Africa, the Canary Islands and in Southern Spain, occasionally also in the Spanish interior. In addition, there are observations known from Malta, very local from Sicily and Turkey.