The Collembolan,oudemansia Esakii,an Intertidal Marine Insect in Hong Kong,with Emphasis on the Floatation Method of Collection

Summary Oudemansia esakii is shown to be a truly marine insect as all stages of the life cycle are found in intertidal sand in Hong Kong. The motile stages migrate vertically and forage during low tide, but burrow into the sand with incoming tidal conditions. An air bubble often forms around them while in the soil. Total forced immersion for 75 hours showed no harmful effects. The greatest burrowing depth is 36 cm and the optimal littoral position is three feet above low water. A floatation method using graded sieves is superior to MacFadyen's high gradient technique. Pertinent hydrographic data are included, as are biological relationships.Marine Science Laboratory, the Chinese University of Hong Kong