EXUVIUM ANALYSIS - A NONDESTRUCTIVE METHOD OF ANALYZING COPEPOD GROWTH AND DEVELOPMENT

Quantitative measurements of individual growth and developmental rates are necessary to study copepod life-history ecology, population dynam ics, and secondary production, yet these measurements are difficult to obtain, particularly for naupliar instars. Copepods molt several time s during their life cycle, and the resulting exuvium provides an accur ate record of an individual's size at molting. Newly hatched nauplii o f two freshwater calanoid copepods (Boeckella triarticulata and Boecke lla hamata) were reared in the laboratory under identical conditions a nd examined daily for the presence of exuviae, which were used to quan tify individual growth and development. Both size and age at successiv e molts were variable among individuals of each species. Some individu als consistently developed more slowly or more rapidly than others, an d individual differences in growth rates also were highly significant. Exuvium analysis provides accurate, quantitative data on individual p atterns of growth and development throughout the life cycle.