Finding a signal hidden among noise: how can predators overcome camouflage strategies?

Abstract

Substantial progress has been made in the past 15 years regarding how prey use a variety of visual camouflage types to exploit both predator visual processing and cognition, including background matching, disruptive coloration, countershading and masquerade. By contrast, much less attention has been paid to how predators might overcome these defences. Such strategies include the evolution of more acute senses, the co-opting of other senses not targeted by camouflage, changes in cognition such as forming search images, and using behaviours that change the relationship between the cryptic individual and the environment or disturb prey and cause movement. Here, we evaluate the methods through which visual camouflage prevents detection and recognition, and discuss if and how predators might evolve, develop or learn counter-adaptations to overcome these. This article is part of the theme issue ‘Signal detection theory in recognition systems: from evolving models to experimental tests'.

Commercial Harvesting Has Driven the Evolution of Camouflage in an Alpine Plant

“…In camouflage search tasks, trichromats do not always perform better than dichromats. Dichromatic vision has long been thought to have advantages in detecting camouflage objects, 27 therefore it is worth comparing it with trichromatic vision in the visual experiment. To simulate the scene that viewed by a general mammalian dichromat with long and shortwave cone types, all trichromatic photographs were also converted into blue-yellow dichromatic images by combing red and green channels (Y = (R + G)/2, in ImageJ, as used by Troscianko et al 11 ).…”

Ambient light and mimicry as drivers of wing transparency in Lepidoptera

“…Moreover, diurnal species vary less in the light they transmit than nocturnal species, suggesting a strong selection for high levels of transmittance. Although both diurnal and nocturnal species are exposed to visual predators during the day, species that are active during the day, independently of the habitat where they fly, are at higher predation risk as they can be more easily detected by their movement (Lyytinen et al 2004; Galloway et al 2020). Therefore, traits reducing this detectability, such as high transparency levels will be strongly selected.…”

Detectability and predator strategy affect egg depredation rates: Implications for mitigating nest depredation in farmlands

“…visually oriented predator) (Robledo-Ospina et al, 2017). The mechanism by which prey coloration may provide camouflage in natural environments has been widely studied (Hughes et al, 2019) but that by which predators respond to prey camouflage and concealment has received less attention (Galloway et al, 2020). Understanding how vegetation structure affects predation risk and predator strategy can help managers design strategies to mitigate (de)predation of threatened or hunted species.…”