Comparative observations on the ecology of four species of ostracods living in a temporary freshwater puddle

Abstract

The population biologies of Cyprinotus carolinensis, Herpetocypris reptans, Cypricercus reticulatus, and Candona decora in a spring-fed, temporary, winter puddle in Vancouver, Canada, were studied during 1967–1969. All species emerged at the same time in the fall, when the puddle filled, and competed to reach maturity. The order of maturation was Candona, Cyprinotus, Cypricercus, and Herpetocypris. Abundance was positively related to adult size of each species. Survivorship and fecundity patterns are given for Herpetocypris and Cyprinotus. Survivorship is closest to the type-I kind.All species have similar feeding appendages and ate grass detritus and its microinhabitants. They differed in their spatial distribution, each species being most abundant along a section of the rut. They also differed in their mobility and foraging patterns. The presence of grass was effective in restricting dispersal. Distribution and abundance of these species may be accounted for either in terms of competitive interactions or in terms of adaptation to physical differences in the environment.