It is possible that in infected individuals the level of serotonin due to increased temperature and parasitic infection combine in the gammarid brain to produce a higher
photophilic response.
Control Program for the
Photophilic Robot, Which Sets the Left and Right Motor Speed Values as a Function of the Six Frontal Light Sensors (Numbered 0-5).
On rocky seafloor the limit is governed by the dominance of
photophilic (sublittoral zone) or sciaphilic seaweeds and suspensivores (circumlittoral zone).
Uninfected Gammarus lacustris, Hyalella azteca, and Gammarus pulex are photophobic and negatively phototactic, but infection with various orange Acanthocephala species reversed their photoreaction: they became
photophilic and positively phototactic.
