Phenotypically plastic neophobia: a response to variable predation risk

Abstract

Prey species possess a variety of morphological, life history and behavioural adaptations to evade predators. While specific evolutionary conditions have led to the expression of permanent, non-plastic anti-predator traits, the vast majority of prey species rely on experience to express adaptive anti-predator defences. While ecologists have identified highly sophisticated means through which naive prey can deal with predation threats, the potential for death upon the first encounter with a predator is still a remarkably important unresolved issue. Here, we used both laboratory and field studies to provide the first evidence for risk-induced neophobia in two taxa (fish and amphibians), and argue that phenotypically plastic neophobia acts as an adaptive anti-predator strategy for vulnerable prey dealing with spatial and temporal variation in predation risk. Our study also illustrates how risk-free maintenance conditions used in laboratory studies may blind researchers to adaptive anti-predator strategies that are only expressed in high-risk conditions.

Testing for local host–parasite adaptation: an experiment with Gyrodactylus ectoparasites and guppy hosts

“…Predators and predator cues are certainly known to have very strong plastic effects on guppy behaviour and growth Evans et al, 2007;Gosline and Rodd, 2007;Brown et al, 2013), and these guppy traits are known to influence infection (Johnson et al, 2011;Richards et al, 2010). Thus, perhaps we would have found very different results had we exposed guppies to predators or predator cues.…”

Patterns of predator neophobia: a meta-analytic review

“…While the dangerous niche hypothesis has traditionally been applied to avoiding the consumption of dangerous foods, a growing body of the literature supports its application to predator neophobia. Brown et al [22] fortified this paradigm by demonstrating that neophobia was a plastic trait within individuals, being induced by exposure to a high-risk environment. In that study, fish and amphibians became neophobic following repeated exposure to injured conspecific cues (hereafter 'alarm cues') that are released during a predator attack, and are innately recognized by conspecifics, reliably indicating risk [39].…”

“…Hence, neophobic animals may avoid deadly encounters with novel predators, and benefit from increased survival. From an evolutionary perspective, phenotypically plastic neophobia [22] helps animals survive their initial encounters with novel predators (e.g. [40,41]), and can facilitate the retention of information learned from the encounter [42].…”

“…visual or chemical) and in timing (before, during or after an attack) [21]. When a stimulus is novel, an animal may demonstrate neophobia because it perceives the stimulus as a possible predation threat [22]. Many animals show fear in novel spaces or areas (electronic supplementary material, table S1) where the environment is potentially dangerous due to unknown predators.…”

Animal cognition in a human-dominated world

“…Here, Ducatez et al (2016) extend this body of work by undertaking a comparative analysis of several avian species on the Caribbean island of Barbados and showing that urban birds are overall bolder, less responsive to human disturbance and have shorter flight distances than their less urbanized conspecifics. Given the taxonomic prevalence of the capacity to learn in the context of predation (Griffin 2004;Lönnstedt et al 2012), such differences might be acquired as a consequence of experience (Brown et al 2013) (but see Carrete and Tella 2011;Sol et al 2013 for other possible explanations). As suggested in a novel contribution by Bílá et al (2016) the capacities to learn about novel predators and to respond to the alarm calls of other species through generalization or learning (Shriner 1999) might well assist animals in dealing with novel threats they encounter in urban areas.…”