The Fifth International Rotifer Symposium was organized by Dr. Claudia Ricci and held in the northern Italian town of Gargnano (Brescia) from September 12-17, 1988. Through the generosity of the Rector of Milano University, a beautiful villa on the shores of Lake Garda was made available to the 83 people from 20 countries who attended the symposium. Ten of these rotifer workers had attended the four previous meetings. Such symposia serve three major functions, the results of which will be apparent in the papers contained in this volume. First, because of the heterogeneity of interests and absence of concurrent sessions, the attendees are exposed to an unusually large variety of research problems, approaches and modes of interpretation. Bridges are thus built between one's own investigations and developments in the field as a whole. Second, the extensive informal interactions that occur outside of the meeting room during coffee breaks, dinners and excursions provide remarkable opportunities for research planning and sharing of results of work in progress. Third, the acquaintances established at these meetings have facilitated interactions during the three-year intervals between symposia. The result has been that visits between laboratories, acquisition of research materials from distant sources and coordination of related investi­ gations have all been greatly enhanced. A description of the week's events may serve to convey the ambience of the meeting.

Rotifer study as a way of life.- Rotifer study as a way of life.- One: Ecology.- Food.- Food limitation and body size in the life cycles of planktonic rotifers and cladocerans.- Is food availability the main factor controlling the abundance of Euchlanis dilatata lucksiana Hauer in a shallow, hypertrophic lake?.- Influence of cyanobacterial diet on Asplanchna predation risk in Brachionus calyciflorus.- Nutritional effect of freshwater Chlorella on growth of the rotifer Brachionus plicatilis.- Life history characteristics of Brachionus plicatilis (rotifera) fed different algae.- Feeding kinetics of Brachionus plicatilis fed Isochrysis galbana.- Competition.- Epizoic and parasitic rotifers.- Interrelations of rotifers with predatory and herbivorous Cladocera: a review of Russian works.- Competitive interactions between the rotifer Synchaeta oblonga and the cladoceran Scapholeberis kingi Sars.- Autoecology.- Salinity and temperature influence in rotifer life history characteristics.- Empirical evidence for a complex diurnal movement in Hexarthra bulgarica from an oligotrophic high mountain lake (La Caldera, Spain).- Morphological variation in Kellicottia longispina.- Morphological structure and functional patterns of Keratella cochlearis (Gosse) populations in stratified lakes.- The development of Hexarthra spp. in a shallow alkaline lake.- On choice of substrate and habitat in brachionid rotifers.- Temporal analysis of clonal structure in a moss bdelloid population.- Horizontal distribution of the plankton rotifers Keratella cochlearis (Bory de St Vincent) and Polyarthra vulgaris (Carlin) in a small eutrophic lake.- Oviposition behavior of the littoral rotifer Euchlanis dilatata.- Developmental times of Synchaeta oblonga eggs from the Danube (Austria).- Communities.- Community structure and coexistence of the rotifers of an artificial crater lake.- The rotifer communities of acid-stressed lakes of Maine.- Composition and distributional patterns in arctic rotifers.- Abundance and diversity of planktonic rotifers in the Po River.- Rotifer distribution in relation to temperature and oxygen content.- Patterns in the composition of the rotifer communities from high mountain lakes and ponds in Sierra Nevada (Spain).- Rotifer associations of some wetlands in Ontario, Canada.- Opportunist rotifers: colonising species of young ponds in Surrey, England.- Percentage of rotifers in spring zooplankton in lakes of different trophy.- Tasmania revisited: rotifer communities and habitat heterogeneity.- Occurrence of Rotifera in the field under natural and intentionally-changed conditions. II. Lake Numasawa.- Two: Taxonomy and Morphology.- The skeletal muscles of rotifers and their innervations.- Classical taxonomy and modern methodology.- Mastax morphology under SEM and its usefulness in reconstructing rotifer phylogeny and systematic.- Problems in taxonomy of rotifers, exemplified by the Filinia longiseta-terminalis complex.- Systematics, reproductive isolation and species boundaries in monogonont rotifers.- Phylogenetic relationships within phylum Rotifera: orders and genus Notholca.- A re-appraisal of two members of the genus Notholca from the Andes, with a note on the fine structure of the lorica of N. foliacea (Ehrenberg).- Three: Physiology.- Protein patterns in rotifers: the timing of aging.- Brachionus plicatilis tolerance to low oxygen concentrations.- Analysis of protein, carbohydrate and lipid in rotifers.- A laboratory study of phosphorus and nitrogen excretion of Euchlanis dilatata lucksiana.- A new method to estimate individual dry weightsof rotifers.- Temperature aspects of ecological bioenergetics in Brachionus angularis (Rotatoria).- Biomass and elemental composition (C.H.N.) of the rotifer Brachionus plicatilis cultured as larval food.- Four: Genetics.- Molecular genetics of rotifers: preliminary restriction mapping of the mitochondrial genome of Brachionus plicatilis.- Size variation in Brachionus plicatilis resting eggs.- Five: Aquaculture.- Rotifers as food in aquaculture.- Nitrogen flow through a Brachionus/Chlorella mass culture system.- Kinetics of n-3 fatty acids in Brachionus plicatilis and changes in the food supply.- Effect of incubation and preservation on resting egg hatching and mixis in the derived clones of the rotifer Brachionus plicatilis.- Intensive rotifer cultures using chemostats.- Author Index.