All camouflage strategies are not equal

Abstract

The difference between life and death can come down to only a couple of seconds or a few millimetres. An animal could avoid being eaten if it can remain undetected for a few extra seconds or cause a predator to misjudge its attack by a few millimetres. Camouflage plays a crucial role in providing these precious seconds or millimetres, but are all camouflage strategies equally effective? 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. Their study provides a valuable synthesis of the current research and highlights several key directions for future studies.Camouflage strategies have evolved in response to multiple selection pressures and vary in their benefits and costs. Some strategies are excellent to avoid detection but ineffective when the prey moves, whereas other strategies help moving prey to evade an attack but have limited effect on reducing detection or recognition. 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. This suggests that avoiding detection or recognition in the first place is most beneficial.The effect of motion dazzle on reducing attack rate may not be fully represented by this meta-analysis due to limited research. Only 17% of studies in the meta-analysis studied this defence, compared to 38% for background matching and 26% for disruptive camouflage. This scarcity of research is likely because it is difficult to capture the complexities of motion dazzle. Motion dazzle requires the movement of both prey and predator, and is also likely to depend on background complexity, background movement and lighting environment. Few studies have tackled this camouflage tactic, and it is a significant gap in our understanding of camouflage strategies. Emerging technologies, such as computer graphics, have allowed researchers to begin to delve into contexts and prey characteristics that influence the success of motion dazzle. These studies demonstrate that effectiveness can depend on prey size, pattern contrast, movement trajectory, speed of movement and background complexity [2-4]. To build on these studies, more research with realistic scenarios and a variety of different predators is required to fully appreciate contexts in which motion dazzle is beneficial.Visual systems can vary dramatically among predators. However, the authors found no differ...

Antipredator defences in motion: animals reduce predation risks by concealing or misleading motion signals

“…Therefore, only focusing on the concept of camouflage is too restrictive when we consider how animals avoid predation whilst in motion. However, the behavioural aspects of animals needing to mislead predators are usually overlooked in antipredation studies, or not measured directly and manipulated (Brodie III, 1989, 1992; Shine & Madsen, 1994; Kelley & Kelley, 2014; De Alcantara Viana et al ., 2022; Franklin, 2022). The lack of empirical research is unsurprising since the component of motion adds an additional layer of complexity that is difficult to measure.…”