Dipartimento di Biologia Evolutiva e Funzionale, Sezione Museo di Storia Naturale, Università di Parma, via Farini 90, Parma, Italy.
Behav Brain Res. 2010 Feb 11;207(1):1-6. doi: 10.1016/j.bbr.2009.09.002. Epub 2009 Sep 6.
Lateralization in ectotherms is now as well studied as in endotherms. Bias in eye use seems widespread, particularly in several ectotherms, most of them having lateral eyes. Several studies evidenced that the right eye/left hemisphere is involved in predatory behaviour and food searching while the left eye/right hemisphere seems to control predator monitoring, making lateralized individuals able to carry out both tasks simultaneously. Starting from previous observations that demonstrated a right-eye/left-hemisphere preference for observing a prey in common wall lizards, Podarcis muralis, we investigated whether a visual lateralization in antipredatory behaviour is present too. In a first experiment, we induced lizards in a terrarium to escape from a simulated predator attacking from behind, recording the direction of the escape path in relation to the starting point. We found that the preferred escape direction of most lateralized individuals was to the right and there was also a strong rightward preference in escape direction as a whole. In a second experiment the lizards, again stimulated from behind, had to choose to run down either the right or the left arm of a semi-circular tunnel ("ram-horn" maze). The rightward preference in escape behaviour was confirmed in this experiment too. We conclude that the constant rightward escape could be due to a left-eye early perception of the threatening cue and to the possibility it gives of better monitoring of most of the terrarium surface. Moreover, we found a left bias in turning the head for monitoring the predatory stimulus during escape, supporting the hypothesis that such a preference is likely due to visual lateralization rather than to motor lateralization.
如今，人们对变温动物的偏侧性研究与对恒温动物的研究一样深入。眼睛使用的偏向性似乎很普遍，尤其是在几种变温动物中，其中大多数动物都有侧眼。一些研究表明，右眼/左半球参与捕食行为和寻找食物，而左眼/右半球似乎控制着对捕食者的监测，使偏侧化个体能够同时执行这两项任务。基于之前的观察结果，即证明了普通壁蜥（Podarcis muralis）观察猎物时存在右/左半球偏好，我们研究了捕食防御行为是否也存在视觉偏侧性。在第一个实验中，我们在一个围栏中诱导蜥蜴逃避来自后方的模拟捕食者的攻击，并记录了与起点相对应的逃逸路径的方向。我们发现，大多数偏侧化个体的首选逃逸方向是向右，而且整个逃逸方向也存在强烈的向右偏好。在第二个实验中，再次从后方刺激蜥蜴，让它们选择在半圆形隧道（“角状”迷宫）的右侧或左侧跑动。在这个实验中，也证实了向右的逃逸偏好。我们得出的结论是，这种持续的向右逃逸可能是由于左眼对威胁线索的早期感知，以及它为更好地监测围栏表面提供了可能。此外，我们还发现，在逃避过程中，头部向左转动以监测捕食刺激存在左偏，这支持了这样一种假设，即这种偏好很可能是由于视觉偏侧性而不是运动偏侧性引起的。
