Patterns of predator neophobia: a meta-analytic review

Abstract

Neophobia, the fear of novel stimuli, plays a major role in animal ecology. Here, we review studies on predator neophobia and explore its underlying patterns within an ecological framework. Predator neophobia is typically assessed by observing behaviours in novel areas that bring potential risk from unknown predators, or by observing behaviours towards certain kinds of objects and odours that are novel. We conducted a literature review across taxa, surveying research on baseline and induced neophobia versus controls. We calculated effect sizes for the intensity of neophobic responses, and categorized data according to six factors (taxa, age class, background type, trophic position, test cue type and experimental treatment type). While accounting for each of the other factors, we found that baseline neophobia was stronger among birds and mammals, and towards novel areas, relative to other taxa and cue types. Baseline neophobia was lower for wild-caught animals and for those that were higher in trophic position, compared with those reared in captivity and from lower trophic levels. By contrast, induced neophobia was similar in intensity across taxa, background types and testing cue types, while again being lower among upper trophic-level members and among juvenile animals. Although induced neophobia occurred across all treatment types, brain lesions induced stronger neophobia than predation risk or social isolation. We discuss potential mechanisms underlying these results and highlight gaps in the literature.

Anti‐predator mechanisms in evolutionarily predator‐naïve vs. adapted fish larvae

“…A possibility that should be tested in follow‐up studies is whether lack of neophobia (e.g., Ferrari et al. , Crane and Ferrari ), or the failure to precociously respond to chemical cues of predators, as seen in arctic charr larvae (Hirvonen et al. ), might play a mechanistic role in this apparent disability.…”

“…In comparison with the two other species, it was remarkable how often predator-na€ ıve whitefish failed to make any observable reaction to an attack, indicating that they lack the overall ability to make innate adaptive anti-predator decisions at this stage of ontogeny. A possibility that should be tested in follow-up studies is whether lack of neophobia (e.g., Ferrari et al 2015, Crane andFerrari 2017), or the failure to precociously respond to chemical cues of predators, as seen in arctic charr larvae (Hirvonen et al 2000), might play a mechanistic role in this apparent disability.…”

“…Thus, it is necessary for developing individuals to alter their behavioral phenotype to adapt to changing predation conditions. Predation has been shown to affect behavioral traits such as neophobia (Crane and Ferrari ), exploration (Dingemanse et al. ), and anti‐predator responses (Quinn and Cresswell ).…”

“…Thus, it is necessary for developing individuals to alter their behavioral phenotype to adapt to changing predation conditions. Predation has been shown to affect behavioral traits such as neophobia (Crane and Ferrari 2017), exploration (Dingemanse et al 2007), and antipredator responses (Quinn and Cresswell 2005). Ultimately, organisms might evolve different anti-predator behaviors and defenses for each life-history stage to match the predator regimes they face in that stage.…”

The socially mediated recovery of a fearful fish paired with periodically replaced calm models

“…In a high-risk environment, fathead minnows, Pimephales promelas, like many species, acquire long-lasting behavioural responses associated with fear such as neophobia (reviewed in [15]). Moreover, this generalized state of fear can be indirectly acquired by social companions in the absence of direct exposure to danger (i.e.…”