Modeling Hydra Behavior Using Methods Founded in Behavior-Based Robotics

7.2. Generation of behavioral organizer 43day, were recorded three times per day. In order to investigate this property of the modeledHydra, simulations of the animal during similar feeding conditions were carried out.First, Hydra was fed during 6.5 minutes every 24 hours, and secondly, the animal was fedfor the same period of time every 72 hours. In each case ten simulation runs were conducted,from which the mean and standard deviation of the contraction frequency werecalculated. The results from simulations, as well as from the experimental study in [46],are presented in Table 7.3.The contraction frequency of animals that are fed every third day is described in [46]as being reduced during the days following feeding. The decrease in frequency, however,is not significant for all recordings. The results from simulations shows a more rapiddecrease than the experimental results, but its qualitative properties agrees with thoseshown by the physical Hydra: Animals fed daily contracts at a higher frequency thananimals fed less often, even immediately after feeding. Also, there is a decrease in thecontraction frequency during the days following feeding in animals fed every three days.Table 7.3: Contractions per hour (mean and standard deviation) in Hydra fed daily and every thirdday, respectively.Experimental data, Simulation resultsevening countFed daily 7.2 ± 0.5 7.98 ± 0.25Fed every third dayFirst day 5.1 ± 0.4 6.15 ± 0.44Second day 4.9 ± 0.4 4.36 ± 0.63Third day 4.8 ± 0.4 3.69 ± 0.14