Variable Description - Data Experiment. Block:Each of the 16 treatments (four chemotypes; two ant treatments (presence and absence); two predator treatments (presence and absence) ) was replicated five times: in five blocks. Day:Day of observation. Aphids, ants and predators in each cage were counted with a mechanical counter on days 0, 2, 4, 6, 8, 11, 14, 17 and 20. Plant_Chemotype:Four different chemotypes were tested: chemotypes 2.1, 2.2, 4.1 and 4.2. Chemotype_Class:The four different chemotypes belonged to 2 chemotype classes: 2 and 4. Plant_Identity:This shows the identity of each individual plant. Each of the 16 treatments was replicated five times resulting in 80 tansy plants (N=80). Biomass:The aboveground biomass of each tansy plant was measured by drying plants at 70 °C for three days for dry weight determination at the end of the experiment [g]. Plant_Growth:Plant growth [cm]: Plant height [cm] at the beginning of the experiment minus plant height [cm] at the end of the experiment. Ant_Treatment:Presence (p) or absence (a). Ant_Abundance:Ant abundance at the day of observation. Predator_Treatment:Presence (p) or absence (a). Predator_Abundance:Predator abundance at the day of observation. Aphid_Abundance:The number of aphids counted on the day of observation.