Predator responses to prey camouflage strategies: a meta-analysis

Abstract

Although numerous studies about camouflage have been conducted in the last few decades, there is still a significant gap in our knowledge about the magnitude of protective value of different camouflage strategies in prey detection and survival. Furthermore, the functional significance of several camouflage strategies remains controversial. Here we carried out a comprehensive meta-analysis including comparisons of different camouflage strategies as well as predator and prey types, considering two response variables: mean predator search time (ST) (63 studies) and predator attack rate (AR) of camouflaged prey (28 studies). Overall, camouflage increased the predator ST by 62.56% and decreased the AR of prey by 27.34%. Masquerade was the camouflage strategy that most increased predator ST (295.43%). Background matching and disruptive coloration did not differ from each other. Motion camouflage did not increase ST but decreases AR on prey. We found no evidence that eyespot increases ST and decreases AR by predators. The different types of predators did not differ from each other, but caterpillars were the type of prey that most influenced the magnitude of camouflage's effect. We highlight the potential evolutionary mechanisms that led camouflage to be a highly effective anti-predatory adaptation, as well as potential discrepancies or redundancies among strategies, predator and prey types.

Predators control pests and increase yield across crop types and climates: a meta-analysis

“…Here, positive effect size values represent lower populations of pests and higher crop yield with the presence of predators. To facilitate the interpretation of the results, we back-transformed the lnR values [(exp lnR −1)]×100, to obtain the differences between treatment and control in percentages (see [59], for example).…”

All camouflage strategies are not equal

“…de Alcantara Viana et al . [ 1 ] examine the efficiency of different camouflage strategies by conducting a thorough meta-analysis. They compare predator search time and attack rate among five different camouflage strategies, three predators and three prey types, showing that both camouflage strategy and prey type can influence effectiveness.…”

“…de Alcantara Viana et al . [ 1 ] provide support for these differing benefits and costs, demonstrating that strategies that prevent prey detection (background matching, disruptive coloration) or prey recognition (masquerade) increase predator search time, whereas strategies that deflect attack or reduce accuracy (eyespots, motion dazzle) do not impact search time. They also found that the three strategies that reduce attack rate—background matching, disruptive coloration and motion dazzle—cause a reduction of similar magnitude.…”

“…de Alcantara Viana et al . [ 1 ] contribute a thorough synthesis and discussion to the rapidly expanding literature on animal camouflage strategies. Of particular importance, their literature search highlights key gaps that require attention, including expanding studies to different predators, habitats and contexts.…”

“…The generality of conclusions from meta-analyses is necessarily constrained by the data they draw from. The studies accumulated by de Alcantara Viana et al [1] were largely from Europe and the UK, with few in tropical locations or other continents. Habitats and predator communities, however, can vary dramatically across continents, between tropical and temperate locations and between aquatic and terrestrial systems.…”