Paper 73. Robert M. Crowell, Cornelis Davids. 1979. The developmental cycle of sponge-associated water mites. Pages 563-566. In: J. G. Rodriguez (editor). Recent Advances in Acarology. Volume I of 2. Proceedings of the V International Congress of Acarology, August 6-12, 1978 at Michigan State University, East Lansing, Michigan, New York: Academic Press, 631 pages.

Keywords: collections of sponge associated water mites have been made to elucidate the ecological cycle of their development in the Netherlands and in North America. The data show that the European species Unionicola minor and U. crassipes have two generations per year. Fertilized females overwinter, producing a population of offspring which mature by mid-summer. A second generation matures by mid-October. Collections of two related North American species indicate a single generation per year with the deutonymph as the over-wintering stage, maturing in early summer and producing offspring which reach the next deutonymphal stage by mid-September. It is concluded that the differences in the cycle are related to climatic differences in the two regions.