Behavioral changes constitute a common response of aquatic animals to predator chemical and/or visual cues. Tadpoles frequently use such signals to evaluate predator presence/activity and, consequently, alter their own behavior to reduce detectability and susceptibility to predation. The present study aimed to test how tadpoles of Bokermannohyla martinsi and Ololygon machadoi respond to the presence of a predator (Belostoma testaceopallidum), regarding background choice and activity levels. Results showed that O. machadoi tadpoles increased the use of yellow backgrounds in the presence of the predator perceived through either chemical or visual cues. Bokermannohyla martinsi, on the other hand, did not show preference for any specific background color or changed activity levels in the presence of any predator cue. Our results corroborate the hypothesis of disruptive coloration as a defense strategy in O. machadoi and indicate that the visible and active tadpoles of B. martinsi may employ a different defensive strategy, possibly relying on a more efficient post detection escape mechanism. This hypothesis is corroborated by the higher activity levels of B. martinsi and lack of response to predator presence regarding either modulation of activity levels or background choice.

行为改变构成水生动物对捕食者化学和/或视觉线索的普遍反应。frequently经常使用此类信号来评估捕食者的存在/活动，并因此改变其自身的行为以降低对捕食的可检测性和敏感性。本研究旨在就背景选择和活性水平，测试Bokermannohyla martinsi和Ololygon machadoi的how对捕食者（Belostoma testaceopallidum）存在的反应。结果表明，在通过化学或视觉线索感知到的捕食者的存在下，马卡多伊O增加了黄色背景的使用。马丁·波克曼诺·海拉（Martinsi）另一方面，在存在任何捕食者线索的情况下，对任何特定的背景颜色或活动水平的变化都没有表现出偏爱。我们的研究结果证实了颠覆性色彩的假设作为一种防御策略O. machadoi和指示的可见和活动的蝌蚪B. martinsi可以采用不同的防守策略，可能依靠更有效的检测后逃逸机制。此假说被马丁内螺旋杆菌较高的活动水平和对活动水平的调节或背景选择对食肉动物的存在缺乏反应所证实。