Protective parenting may have population-level consequences

In many animal species, recruitment is facilitated by adults' efforts to protect offspring from predation. Theoretical studies of this phenomenon have usually focused on resolving the conflict between an individual's self-preservation and its attempts to successfully reproduce. While the decision to protect is made at the level of a single individual, the aggregation of these decisions may affect population density and structure. This idea motivates the development of a functional response for predators that is compatible with the protective behaviour of prey. We use this functional response to study the longterm behaviour of a protective prey population under different levels of predation. We find that contribution of protective effort may promote or inhibit population density depending on the riskiness associated with interference. Moreover, our results sugget that, in environments characterised by intense predation, a protection-driven Allee effect allows sufficiently large populations to persist. We interpret these results in the context of different strategies for newborn defence. (C) 2017 Elsevier B.V. All rights reserved.