Effect of parental care and aggregation on population dynamics

Behavioral changes of animal species can influence the consequence of population dynamics. One of the most remarkable behaviors of animal species is the aggregation by which species can reduce predation risk as a consequence of dilution or the other effects by forming a group. Empirical studies have demonstrated that an incompatibility exists in aggregation since resource competition might become severe at the cost of reducing predation pressure from predatory species. Parental care by supplying the food consumed by adults to their juveniles would reduce the mortality of juvenile due to starvation, but it would reduce the reproduction rate at the same time. In this paper, we study a class of stage-structured resource-consumer models to investigate the effect of behavioral changes on population dynamics. It is shown that under the presence of trade-off in parental care, moderate degrees of parental care will be favored as maximizing the equilibrium density of consumers. For consumer species having a long maturation period, consumer species might get benefit from dilution effects as a result of aggregation despite the elevated resource competition. Aggregation gives rise to two different outcomes in consumer extinction. Resource exhaustion as a consequence of over-exploitation can induce extinction of consumers due to Allee effects if aggregation strongly mediates juvenile survival.