Non-interactive multiple predator effects on tadpole survival

Abstract

We estimated interactions among and within three species of predator in their effects on prey survival using short-term predation experiments. The prey were Rana temporaria tadpoles, and the predators were dragonfly larvae (Anax imperator), newts (Triturus alpestris), and backswimmers (Notonecta glauca). Mortality rate per predator imposed by Triturus and Notonecta did not decline with predator density, whereas the predation rate of Anax was strongly reduced when the number of predator individuals increased. Impacts of all three predators were not altered by the presence of other species in pairwise combinations. This system is therefore characterized by interference between individual dragonflies but relatively independent effects of predator species. These results were largely predictable based on the natural history of the predators, and are encouraging for attempts to model communities as assemblages of interacting species. Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland Abstract We estimated interactions among and within three species of predator in their effects on prey survival using short-term predation experiments. The prey were Rana temporaria tadpoles, and the predators were dragonfly larvae (Anax imperator), newts (Triturus alpestris), and backswimmers (Notonecta glauca). Mortality rate per predator imposed by Triturus and Notonecta did not decline with predator density, whereas the predation rate of Anax was strongly reduced when the number of predator individuals increased. Impacts of all three predators were not altered by the presence of other species in pairwise combinations. This system is therefore characterized by interference between individual dragonflies but relatively independent effects of predator species. These results were largely predictable based on the natural history of the predators, and are encouraging for attempts to model communities as assemblages of interacting species. Institute of Evolutionary Biology and Environmental Studies, University of

Predation risk and habitat complexity modify intermediate predator feeding rates and energetic efficiencies in a tri‐trophic system

“…For Sympetrum, we only found an increase in feeding rate in response to chemical cues but no differences between the control without the predation risk and either predation risk treatment; these results are not consistent with observations that it responds primarily to visual predation risk stimuli (Corbet, 2004;Crespo, 2011). Non-overlapping habitat domains may also render the prey unreceptive to predation risk cues (Anderson & Semlitsch, 2016;Ramos & Van Buskirk, 2012;Schmitz, 2007). Ischnura typically prefers early succession sites with few aquatic plants, while Aeshna larvae mostly occur in more densely vegetated habitats (Corbet, 2004).…”

Giants, Dwarfs and the Environment – Metamorphic Trait Plasticity in the Common Frog

“…Non-independent effects of multiple predator species were reported in several predator-prey systems [34], [35]. For predators present in our study system, however, Ramos and Van Buskirk [36] reported no interaction effects between backswimmers, newts and dragonfly larvae, and a constant mortality rate per predator for backswimmers ( Notonecta sp.) and newts ( I. alpestris ), independent of predator-density.…”

“…and newts ( I. alpestris ), independent of predator-density. In an experimental setup dragonfly larvae proved to be more effective in killing R. temporaria tadpoles than other predators [28], but also to interfere with each other, thus lowering their predation rate when occurring in higher densities [36]. Therefore, we considered the use of overall predator-density being the most appropriate surrogate for predation risk in our study, neglecting the potential differences in relative dangerousness of predator species [28], [37].…”

The importance of intraguild predation in predicting emergent multiple predator effects

“…We used likelihood ratio tests to compare models assuming substitutability between predators with models devoid of assumptions about their interactive effects on Pardosa survival (Ramos and Van Buskirk 2012). We used likelihood ratio tests to compare models assuming substitutability between predators with models devoid of assumptions about their interactive effects on Pardosa survival (Ramos and Van Buskirk 2012).…”