Density, Size, and Clutch of Two High Altitude Diaptomid Copepods

Population characteristics of two copepod species, Diaptomus shoshone Forbes and Diaptomus coloradensis Marsh, and both interspecific and intraspecific interactions are examined. Both species vary in size among years and among several high altitude ponds in Colorado. Larger individuals with larger clutches are found in ponds where the density of developing individuals is low. Size differences can occur as a result of conditions in nauplii or copepodid stages. Clutches of both species vary in a given pond as the season progresses, but larger individuals carry larger clutches, and, at least in D. shoshone, first clutches are found on large individuals. There is little interaction between the two species, and temperature does not affect adult size.