On the Evolution of Energy Balance in Some Exploiter‐Victim Systems

Abstract

By means of mathematical models and an experimental system we argue that density—dependent genetic feedback has the potential to regulate the amount of energy taken by a predator (parasite and herbivore) population from the prey or host population. The experimental system was a simulation using the housefly, Musca domestica, with artificial reproduction and prey, thereby restricting predator population feeding and adjusting it to surplus energy of the prey or host population. The experimental predator population, controlled by genetic feedback, was adjusted to a mean density of about 53 animals and in turn was removing less than the total amount of energy available from the prey population. The control predator population, regulated only by competition, fluctuated wildly about a mean density of about 147 animals, and consumed about 78% of the energy available from its prey population. Fluctuations existed in the experimental predator population, but were significantly damped compared with those in the control. These results generally complement those of earlier mathematical models, and support the idea that prey evolution can enhance predator stability and lead to a balanced supply—demand economy between predator and prey. In nature, the genetic feedback mechanism must function interdependently with other population control mechanisms, but the attempt here is to isolate the mechanism and assess its effect.