Population dynamic theory of size–dependent cannibalism

TLDR

Cannibalism involves killing, energy gain, size‑dependent interactions, and intraspecific competition. The review aims to link these four defining aspects to the predicted population dynamic consequences of cannibalistic populations. The analysis identifies five classes of cannibalism effects: regulation of population size, destabilization, stabilization, bistability, and modification of size structure. The study demonstrates that cannibalism’s effects are not uniquely determined by its aspects, vary with species and context, and influence community structure.

Abstract

Cannibalism is characterized by four aspects: killing victims, gaining energy from victims, size–dependent interactions and intraspecific competition. In this review of mathematical models of cannibalistic populations, we relate the predicted population dynamic consequences of cannibalism to its four defining aspects. We distinguish five classes of effects of cannibalism: (i) regulation of population size; (ii) destabilization resulting in population cycles or chaos; (iii) stabilization by damping population cycles caused by other interactions; (iv) bistability such that, depending on the initial conditions, the population converges to one of two possible stable states; and (v) modification of the population size structure. The same effects of cannibalism may be caused by different combinations of aspects of cannibalism. By contrast, the same combination of aspects may lead to different effects. For particular cannibalistic species, the consequences of cannibalism will depend on the presence and details of the four defining aspects. Empirical evidence for the emerged theory of cannibalism is discussed briefly. The implications of the described dynamic effects of cannibalism are discussed in the context of community structure, making a comparison with the community effects of intraguild predation.