The evolution of the irreversible transition from a free-swimming state to an immobile sessile state in aquatic invertebrates modelled in a chemostat

To better understand the environmental factors and ecological processes underlying evolution of irreversible transition from a free-swimming state to an immobile sessile as seen in many aquatic invertebrates, we study adaptive dynamics settling rate hypothetical microorganism onto wall chemostat. The two states, floating or settled, differ their nutrient ingestion, reproduction death rate. We consider three different mechanisms involving competition for space on wall: (i) purely exploitative where individuals settle vacant only, (ii) mixed interference attempt any place but fail die if is already occupied, (iii) competition, now occupied successful former occupant dies. In simplified environment chemostat, input concentration nutrients dilution tank are main control variables. Using theory dynamics, find that variables have qualitatively effects terms direction well species diversity. case small change settings can lead abrupt reversal evolution, while effect gradual. For all mechanisms, periodic fluctuations open possibility evolutionary branching leading long-term coexistence intermediate infinitely high rates (in low-frequency fluctuations), zero high-frequency fluctuations).