NATURAL RESOURCE MODELING Volume 28, Number 2, May 2015 COMPONENT ALLEE EFFECTS AND STAGE-SPECIFIC PREDATION: A BRIEF INSIGHT INTO CONSERVATION AND BIOLOGICAL CONTROL ISSUES MICHEL ISKIN DA S. COSTA Laborat´ orio Nacional de Computa¸ c˜aoCient´ ıfica, Av. Get´ ulio Vargas, 333 Quitandinha, Petr´ opolis (RJ), 25651-070 Brazil E-mail: michel@lncc.br LUCAS DOS ANJOS* Laborat´ orio Nacional de Computa¸ c˜aoCient´ ıfica, Av. Get´ ulio Vargas, 333 Quitandinha, Petr´ opolis (RJ), 25651-070 Brazil E-mail: lanjos@lncc.br Abstract. In this paper, we propose a two-stage structured popula- tion model subject to component Allee effects in fecundity and maturation, and with two disturbances (predation only and harvest and predation) act- ing on both stages. It is shown that this combination leads to a demographic Allee effect—a characteristic that could be exploited in pest biological con- trol, but on the other hand, it represents a bane in conservation biology. The analysis is performed for disturbances with functional responses type 2 and 3, and the models show that they yield qualitatively similar results. This characteristic is discussed from the species conservation and biological control point of view, together with possible extensions of this work. Key Words: Component Allee effects, stage-structured models, biological control, species conservation. 1. Introduction. Studies of specialist predator-prey dynamics by means of un- structured models with demographic Allee effects in prey have been performed in or- der to evaluate their consequent dynamics (Boukal et al. [2007]). On the other hand, examples of different predators feeding on juveniles and adults of a prey species are common in natural systems (e.g., predation on Utah prairie dogs (Hoogland et al. [2006]); predation on Daphnia (Manca et al. [2008]). In this respect, analyzes of structured predator-prey models in which predator density is kept constant and prey population is stage structured have also been performed (Pavlov´ a and Berec [2012]). In this work, we combine these two mathematical modeling structures in order to evaluate impacts of predation on the dynamics of a prey population struc- tured in two-stage classes, juveniles and adults. An additional feature is that each class not only suffers component Allee effects (Courchamp et al. [2008]), but each is also consumed by a different generalist predator as well. ∗ Corresponding author. Lucas dos Anjos, Laborat´ orio Nacional de Computa¸ c˜aoCient´ ıfica, Av. Get´ ulio Vargas, 333 Quitandinha, Petr´ opolis (RJ), 25651-070 Brazil, e-mail: michel@lncc.br Received by the editors on 23 rd August 2014. Accepted 30 th March 2015. Copyright c  2015 Wiley Periodicals, Inc. 169