Three fairy shrimp species (freshwater Anostraca) (including three populations of Streptocephalus proboscideus) and four clam shrimp species (Spinicaudata), from different African arid and semi-arid regions, were studied under laboratory conditions with respect to their fecundity, the hatchability of their resting eggs, and culturing potential. Fecundity rate was significantly higher in the clam shrimps, but the longer life span of the anostracans resulted in total fecundity being not significantly different (P >0.05). Fecundity variables were not found to differ significantly (P >0.05) among three successive periods of the reproductive period for any of the species tested. The smaller mean egg size in spinicaudatans (182 +/- 40 mum), in comparison with the fairy shrimps (255 +/- 41 mum), might be explained in terms of size constraints rather than by a difference in ecological strategy. Egg size was furthermore significantly different (P <0.05) between all pairs of species (except between the clam shrimps Leptestheria aegyptiaca and Eocyzicus klunzingeri) and even between different populations of Streptocephalus proboscideus. The fact that part of the eggs produced are quiescent in E. klunzingeri (100 %); S. proboscideus (Sudan), S. proboscideus (from site SWA48; Namibia), and S. sudanicus (10-30 %); S. proboscideus (from site SWA 42; Namibia), and S. ovamboensis (0-5 %), is a major advantage for practical applications, since no elaborate diapause deactivating techniques are required to start the next active generation.