Recent work also demonstrates how moths change their resting posture based on individual levels of camouflage 28. In addition, ground-nesting birds from nine different species improved their level of camouflage by choosing appropriate backgrounds across multiple spatial scales 29. Both the nesting substrate preference of laboratory Japanese quail ( Coturnix japonica) 26 and the resting spots of wild Aegean wall lizards ( Podarcis erhardii) 22, for example, have been shown to be closely tied to individual appearance of eggs and adults, respectively. However, recent work has demonstrated the existence of background choice at an individual level for improving concealment. Despite the intuitiveness of this idea there has historically been a lack of consistent experimental investigation into this area 27, and few rigorous tests of how and when behavioural choices facilitate crypsis on natural substrates have been conducted. The drivers and outcome of longer-term colour change for camouflage to predator vision has rarely been properly quantified.Īside from direct colour adaptations, animals may also facilitate camouflage by behaviourally choosing appropriate backgrounds 22, 23, 24, 25, 26, 27, 28. This may include seasonal changes in habitat availability. The function of slower changes can be less intuitive 13, although alterations occurring over a period of days–weeks likely improve concealment in response to predictable and slow environmental changes or associated with life history 11. chameleons 16, cuttlefish 17 and fish 18, 19, 20, 21) since it provides a response to environments that change unpredictably in the short term 11. The benefit of rapid colour change for crypsis in many animal groups is clear (e.g. seconds/minutes) as opposed to slower changes (days/weeks), despite the latter likely being more prevalent across taxonomic groups 13, 15. Research has tended to focus on animals capable of rapid change (i.e. Of these strategies, colour change is widespread in nature and allows individuals of many species to adjust the colour aspect of their camouflage to both the environment and to the visual systems of different predators 13, 15. Therefore, an array of adaptations exist to overcome this problem, including generalist coloration, colour polymorphisms, ontogenetic changes, colour change and behaviourally oriented choices 1, 3, 12, 13, 14. However backgrounds within natural habitats are rarely uniform and vary considerably in colour and pattern across space and time 11. Crypsis works by reducing the chance of prey detection or recognition by the visual system of potential predators 1, 6, 7, often through background matching 1, 5, 8, 9, 10. We demonstrate how colour change and behaviour combine to facilitate camouflage against different substrates in environments varying spatially and temporally.Ĭryptic coloration allowing visual camouflage is a cosmopolitan antipredator strategy in nature and provides classic examples of evolution by natural selection 1, 2, 3, 4, 5. However, colour change occurs over weeks, consistent with seasonal changes in algal cover, whereas behavioural choice of matching substrates occurs in the short-term, facilitating matches within heterogeneous environments. Prawns also select colour-matching substrates when offered a choice. Here we show that green and red chameleon prawns ( Hippolyte varians) closely resemble their associated seaweed substrates to the vision of predatory fish, and that they can change colour to effectively match new backgrounds. However, previous work largely considered these solutions in isolation, whereas many species may use a combination of behaviour and appearance to facilitate concealment. Therefore, species often exhibit adaptive traits to maintain crypsis, including colour change and behavioural choice of substrates. Camouflage is driven by matching the visual environment, yet natural habitats are rarely uniform and comprise many backgrounds.
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