A comparison of some environmental adaptations of the littoral collembolans Anuridella marina (Willem) and Anurida maritima (Guérin)

Cuticle structures of A. marina and A. martima are discussed, the differences are correlated with a greater tolerance of desiccation in A. maritima. The cuticle ornamentation of A. maritima can trap a layer of water-saturated air thus slowing down water loss and allowing it to forage in the drier upper littoral, while A. marina, without a layer of water saturated air, is confined to more humid habitats in the lower littoral. Both species have a compressible macroplastron supported by major tubercles, as well as a much thinner microplastron supported by minor tubercles which is more resistant to wetting by pressure and surfactants. The plastrons are shown to be preadaptations to the littoral zone.