*2.1. Experimental Animals*

Three replicates of the experiments were performed. In order to assess the species rather than the clone-specific effects—each replicate was performed using a different clone of *D. magna* (MB, MN, and MD of body size at first reproduction 1.86 ± 0.22, 1.82 ± 0.13, and 1.83 ± 0.31 mm, respectively) [53]. Clone MB was sampled from Lake Binnen (54◦19 29 N; 10◦37 39 E, Germany), clone MN from the Nový Rybnik pond (50◦13 27.8 N; 14◦4 3.1 E, Czech Republic), and clone MD from the Domin pond (49◦00 21.3 N; 14◦26 29.1 E, Czech Republic). Daphnia was cultured in 5 L containers, with 25 individuals per container, at room temperature and with a natural photoperiod. The daily food supply was added ad libitum in the amount of 1.6 mg C × <sup>L</sup>−<sup>1</sup> of unicellular green algae, *Chlamydomonas klinobasis* (strain SAG 56) from a stationary phase, a chemostat culture grown in a WC medium [54]. The algal concentration was assessed using a portable fluorometer (AquaFluor handheld fluorometer, Turner Designs®, San Jose, CA, USA).
