The visual properties of the background occupied by organisms are a key aspect of visual camouflage. Changes in background coloration by fires may mediate the differential survival of prey against visually oriented predators and modify the prey camouflage strategy. This phenomenon may be common in environments where the fire is a continuous modulator of the community, such as Neotropical savannas. In this study, we investigated whether arthropods match burned and unburned trunks in coloration in order to camouflage relative to the visual system of potential bird predators. We also investigated in which type of the trunk the black and brown morphotypes of Ronderosia bergii (Orthoptera) preferentially occupy and whether the morphotypes present colour matching in the burned and unburned trunks. We recorded the arthropod community on backgrounds against which they had low contrast relative to other available backgrounds. We found that specimens of R. bergii preferentially occupy burned backgrounds. In addition, we also found that black morphotypes of R. bergii showed lower contrasts on burned trunks to the achromatic channel, while browner morphotypes showed lower contrasts on unburned backgrounds in the chromatic channel. We propose three explanations operating behind the observed pattern of the studied community: differential predation; background selection; and animal colour change.

中文翻译：

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新热带稀树草原燃烧和未燃烧背景中节肢动物的颜色匹配

生物所占据的背景的视觉特性是视觉伪装的一个关键方面。火灾引起的背景颜色变化可能会调节猎物对视觉捕食者的生存差异，并修改猎物的伪装策略。这种现象在火灾是社区持续调节剂的环境中可能很常见，例如新热带稀树草原。在这项研究中，我们调查了节肢动物是否在颜色上匹配燃烧和未燃烧的树干，以便相对于潜在鸟类捕食者的视觉系统进行伪装。我们还研究了Ronderosia bergii的黑色和棕色形态类型在哪种类型的树干中（直翅目）在烧伤和未烧伤的躯干中优先占据以及形态类型是否呈现颜色匹配。我们在与其他可用背景相比对比度较低的背景上记录了节肢动物群落。我们发现R. bergii的标本优先占据烧焦的背景。此外，我们还发现，R. bergii的黑色形态类型在燃烧的树干上与消色差通道的对比度较低，而棕色的形态类型在彩色通道的未燃烧背景上的对比度较低。我们提出了在所观察到的社区模式背后的三种解释：差异捕食；背景选择；和动物的颜色变化。