Serological techniques, used to produce antisera to mammalin tissues, were later adapted to studies of invertebrate predator-prey relationships. The first invertebrate predator-prey studies attempted to identify predators of immature mosquitoes. The techniques were then introduced to investigation of predators of economically important pest insects, then to predators of natural enemies of weeds and other plants, and to predators and prey of freshwater planarians. Use of the techniques in studies of the population dynamics of invertebrates demands, but is producing, additional development and precision in methodology.