Are multiple predator effects directed by prey availability?

• Published in: Basic and applied ecology 2013-11, Vol.14 (7), p.605-613
• Main Authors: Lampropoulos, Panagiotis D., Perdikis, Dionyssios Ch, Fantinou, Argyro A.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; community structure; experimental design; foraging; Functional response; Fundamental and applied biological sciences. Psychology; habitats; interspecific competition; Macrolophus pygmaeus; Multiple predator effect; Nesidiocoris tenuis; predators; Prey density; risk; risk reduction; satiety; Synecology; Terrestrial ecosystems; Tomato
• ISSN: 1439-1791
• DOI: 10.1016/j.baae.2013.08.004

Antagonistic/synergistic interactions among predators foraging on the same prey have been assumed to play a major role in shaping community structure. Studies in systems with multiple predator species have shown that the strength of these interactions may not be predictable and is largely dependent on individual behavioural traits, species density and habitat complexity. Although the association of prey consumption and satiation of a foraging predator has long been recognized, there has been relatively little research on how prey availability affects multiple predators’ effects. In this work, we present a framework to investigate the variation in two coexisting/competing predators’ effects on prey risk as affected by the prey availability rate. Functional responses by each predator species were first studied in single-predator treatments. Then, the intra- and inter-specific competition was investigated by employing additive and substitutative experimental designs to highlight the nature of multiple effects. Intra- and interspecific interactions were found to be similar and there was risk reduction, and risk enhancement for the prey at intermediate and high levels, respectively, according to the multiplicative risk model (MRM). The results indicated that when similar predators are concerned, the outcomes of MRM may vary according to the functional response curve of these predators. Thus, studies involving a wide range of prey densities are required to explore the nature of interactions. Moreover, this kind of experimental data can contribute to unravelling complexities in theoretical approaches by earlier studies and ultimately promote understanding the effect of multiple predators on prey population regulation. Es wird angenommen, dass antagonistische oder synergistische Interaktionen zwischen Prädatoren, die sich von der gleichen Beute ernähren, eine große Rolle bei der Ausprägung von Lebensgemeinschaftsstrukturen spielen. Untersuchungen in Systemen mit mehreren Prädatorarten haben gezeigt, dass die Stärke dieser Interaktionen nicht vorhersagbar sein kann und weitgehend von den individuellen Verhaltensmerkmalen, der Dichte der Arten und der Habitatkomplexität abhängig ist. Obwohl der Zusammenhang zwischen der Beuteverwertung und der Sättigung des fressenden Prädatoren schon lange erkannt wurde, gab es relativ wenig Forschung darüber, wie die Beuteverfügbarkeit die Effekte mehrerer Prädatoren beeinflusst. In dieser Arbeit präsentieren wir ein Bezugssystem,