<i>Colotis lais</i> (Butler, 1876) and <i>Colotis euippe omphale</i> (Godart, [1819]) use <i>Cadaba aphylla</i> (Thunb.) Wild LC as a host-plant at Tswalu Kalahari, Northern Cape Province, South Africa)

This article reports the first host-plant species record for Colotis lais (Pieridae), the shrub Cadaba aphylla (Capparaceae). It includes a first description of the final instar larva and the pupa for this species. It furthermore indicates the frequent use of C. aphylla as a host plant by Colotis euippe omphale (Pieridae) in the southern Kalahari. The visible concentrations of C. aphylla at these terrain units influence the conspicuous presence of C. lais and C. euippe omphale at riparian zones in this region. The use of C. aphylla at riparian zones in semi-arid Kalahari bioregions (arid savanna), which encounter periodic droughts, is therefore important for the survival of these species. These findings prompt a change in the perspective on host-plant use of Pieridae butterflies in the southern Kalahari. Although C. aphylla is not the main source for the abundance of pierids in the region, it clearly supports their numbers to a greater degree than has been assumed. Boscia albitrunca and Senna italica are the main host sources, but C. aphylla decidedly influences the diversity and abundances of Pieridae butterfly species in the southern Kalahari. This emphasises the importance of a regional perspective on host-plant use by butterfly species. These findings about the host-plant use and landscape ecology of butterflies at Tswalu Kalahari show that C. aphylla is a keystone species that calls upon further research.