The role of chemoreception in the formation of sustainable populations of Daphnia longispina: Simulation experiments

A new modification of the previously designed individual-based simulation model of population dynamics of a mass pelagic species, Daphnia longispina is presented. The model describes a population as an ordered list of individuals with specific sets of traits. For each individual, its energy traits are calculated, and the probabilities of different outcomes are assigned or calculated for various life situations. This variant significantly differs from the previous chemosignal blocks that modify Daphnia behavior. After receiving a chemical signal (predator kairomones or sex pheromones), adult Daphnia of the model population can avoid predation with a certain probability by diel vertical migrations and can increase the efficiency of sexual reproduction through the active search for a sexual partner. Simulation experiments in which the ability to detect different chemical signals was excluded, sequentially or in combination, were used to investigate the role of chemoreception in the population dynamics and the seasonal adaptations of planktonic crustaceans. For the first time, a quantitative estimate for the role of such information has been obtained as the ratio between the annual production levels of model populations that possess or lack the ability to perceive chemical signals of predators and mating partners. According to the present version of the model, chemoreception increased the annual production of the model population by 1.5 times. Thus, biological information is a significant factor enabling individual hydrobiont populations to fine-tune their adaptations to the particular environmental conditions of a given aquatic habitat.