No trade‐offs in interspecific interference ability and predation susceptibility in newt larvae

Abstract

Coexistence of species with similar requirements is allowed, among others, through trade‐offs between competitive ability and other ecological traits. Although interspecific competition is based on two mechanisms, exploitation of resources and physical interference, trade‐off studies largely consider only species’ ability to exploit resources. Using a mesocosm experiment, we examined the trade‐off between interference competition ability and susceptibility to predation in larvae of two newt species, Ichthyosaura alpestris and Lissotriton vulgaris. In the presence of heterospecifics, L. vulgaris larvae slowed somatic growth and developmental rates, and experienced a higher frequency of injuries than in conspecific environments which suggests asymmetrical interspecific interference. During short‐term predation trials, L. vulgaris larvae suffered higher mortality than I. alpestris. Larvae of the smaller species, L. vulgaris, had both lower interference and antipredator performance than the larger I. alpestris, which suggests a lack of trade‐off between interference competition ability and predator susceptibility. We conclude that interference competition may produce a positive rather than negative relationship with predation susceptibility, which may contribute to the elimination of subordinate species from common habitats.

Impacts of predator‐induced behavioural plasticity on the temperature dependence of predator–prey activity and population dynamics

“…We largely applied the protocol from our previous mesocosm studies (Hloušková et al., 2018; Winterová & Gvoždík, 2018). We used 30 outdoor glass fibre tanks (90 × 63 × 47 cm).…”

Underwater sound production varies within not between species in sympatric newts

“…Assuming that newts detect individual acoustic differences, sound cues may provide information about the number of individuals in their proximity. This may reduce intra- and interspecific competition in these taxa (Janča & Gvoždík, 2017; Hloušková et al, 2018). In addition, if the sex and species identity of approaching individuals is determined using chemical scents (Malacarne & Vellano, 1987; Cogälniceanu, 1994; Treer et al, 2013), acoustic cues may contribute to this recognition by their combination with olfactory cues in darkness.…”

Thermoregulatory opportunity and competition act independently on life‐history traits in aquatic ectotherms

“…They usually metamorphose during late summer (August–September), although they may overwinter or become paedomorphic in some populations (Denoel et al, 2001). Larvae of both species compete for food resources exploitatively and through interference (Hloušková et al, 2018).…”

“…amphibians, behavioural thermoregulation, climate change, fitness, metamorphosis, species interactions Gvoždík, 2012), the larvae of both species compete for resources (Hloušková et al, 2018) and social interactions between competitors affect their behavioural thermoregulation (Winterová & Gvoždík, 2018). The larvae of competitively dominant species (I. alpestris) improved their thermoregulatory accuracy, that is, the absolute difference between actual body temperature and the boundaries of their target (preferred) range (Hertz et al, 1993), in the presence of subordinate species.…”

“…In this study, I performed a mesocosm experiment to test the interactive effect of thermoregulatory opportunity and competition on the life‐history traits in larvae of two newt species, the alpine newt Ichthyosaura alpestris and the common newt Lissotriton vulgaris . Newt larvae are a suitable system for such a task as they show temperature preferences in both vertical and horizontal thermal gradients (Gvoždík et al, 2013; Smolinský & Gvoždík, 2012), the larvae of both species compete for resources (Hloušková et al, 2018) and social interactions between competitors affect their behavioural thermoregulation (Winterová & Gvoždík, 2018). The larvae of competitively dominant species ( I. alpestris ) improved their thermoregulatory accuracy, that is, the absolute difference between actual body temperature and the boundaries of their target (preferred) range (Hertz et al, 1993), in the presence of subordinate species.…”