The almost invisible league: crypsis and association between minute fishes and shrimps as a possible defence against visually hunting predators

Abstract

Camouflage is one of the most widespread defence modes used by substrate-dwelling animals, whereas transparency is generally found in open-water organisms. Both these defence types are regarded as effective against visually guided predators. We present here three assemblages of similarly-sized freshwater fish and shrimp species which apparently rely on camouflage and transparency to evade some of their potential predators. In one of the associations, there is a transition from cryptic colours and translucency to transparency of the component species according to the position each of them occupies in the habitat. The likeness between the fishes and the shrimps is here regarded as a type of protective association similar to numerical or social mimicry. Additionally, we suggest that the assemblage may contain Batesian-like mimicry components.Camuflagem é um dos tipos de defesa mais bem distribuídos entre os animais que vivem no substrato, sendo a transparência geralmente encontrada em organismos pelágicos. Ambos os tipos de defesa são considerados como eficientes contra predadores visualmente orientados. Apresentamos três conjuntos de espécies de peixes e camarões de tamanhos similares, que aparentemente dependem da camuflagem e transparência para escapar de potenciais predadores. Em uma das associações, há uma transição de coloração críptica ou translúcida para transparente, de acordo com a posição que cada espécie ocupa no habitat. A semelhança entre peixes e camarões é aqui considerada como um tipo de associação protetiva, similar a mimetismo numérico ou social. Além disso, sugerimos que o conjunto pode conter elementos similares ao mimetismo Batesiano.

Animal camouflage: current issues and new perspectives

“…Camouflage is a technique especially useful if the animal can change colour to match the background on which it is found, such as can some cephalopods (Hanlon & Messenger 1988) and chameleons (Stuart-Fox et al 2008). Further remarkable examples include insects bearing an uncanny resemblance to bird droppings (Hebert 1974) or fish resembling fallen leaves on a stream bed , to even making the body effectively transparent, as occurs in a range of, in particular, aquatic species (Johnsen 2001;Carvalho et al 2006). Examples such as leaf mimicry in butterflies helped convince Wallace (1889), for example, of the power of natural selection.…”

Molecular Characterisation of Colour Formation in the Prawn Fenneropenaeus merguiensis

“…The latter appears to be the main role of body colouration in aquatic animals, such as prawns. For instance, some prawns protect themselves from predators by changing their body colour intensity to better adapt to their surroundings, while others use their transparent body combined with disruptive colouration to disguise their body outline from predators [1], [3], [5], [6]. Additionally, body colouration can also protect these aquatic animals from UV radiation, ensuring their continued health [7].…”

Air‐breathing Behavior of the Jeju Fish Hoplerythrinus unitaeniatus in Amazonian Streams

“…The formation of groups, for example, is widely cited as an important anti‐predatory mechanism because the synchronized movement can confuse the predator (Partridge , Carvalho et al . ). In addition, group formation increases the chances of prey escaping in various directions in the presence of a potential predator, allowing efficient evasion (Milinski ).…”