Strains and culture conditions
For the experiment presented here six H. oligactis strains were
used (three male strains: C2/7, M83/4 and T3/2 and three female strains:
X11/14, M26/9/10 and T3/1). All strains were established from a single
individual that was collected from freshwater bodies in Eastern Hungary
between 2016 and 2020 and asexually propagated in the lab under
simulated summer conditions (Gergely & Tökölyi in press ). These
conditions include 18 ºC temperature and 12/12 hours light/dark cycle.
Polyps were kept individually in 6-well tissue culture plates containing
artificial hydra medium (1mM Tris, 1mM NaCl, 1mM CaCl2,
0.1mM KCl, 0.1mM MgSO4; pH: 7.6) and they were fed and
cleaned four times per week.