English: The calcium homeostasis of "modern" sperm cells looks very similar to that of "ancient" choanoflagellates.
The reasoning underlying the comparison between a sperm cell and a choanoflagellate is: If we want to better understand the role of the insect male accessory gland juvenile hormone (MAG-JH), we should ask which evolutionarily ancient functions could be stimulated by the presence of JH (or farnesol) or inhibited by its absence. Farnesol is very ancient in evolution. The type of membrane receptor inhibited by farnesol (and its esters), namely a voltage-gated Ca2+ channel type (among other candidates) is also evolutionarily ancient. It goes back at least as far as the Opisthokonta (or Choanozoa), unicellular organisms with a flagellum, which preceded the animals.