ABSTRACT

This paper reports a series of tests for fore- and hind-limb preferences used by cane toads, Rhinella marina, to assist returning to the righted position after being overturned. We confirm the strong and significant right-handedness reported in this species, which under certain conditions exceeded 90% right-hand preference at the group level. Toads were tested under a variety of conditions including horizontal and inclined surfaces, with and without the opportunity for the forelimbs to grasp a support, in order to assess the effects of different vestibular and proprioceptive input on the strength and direction of fore- and hind-limb preferences. A range of behavioural strategies indicated learning effects; however, the strength or direction of limb preferences did not increase significantly with experience, even in toads retested multiple times. Comparisons with the mammalian condition for limb preferences are discussed with relevance to practice effects and established limb preferences, and to effects associated with arousal or stress. In contrast to the expectation that handedness in toads represents intentional or voluntary preferences, the presence of lateralized central pattern generators in the toads is postulated to explain the different forms of lateralization revealed by our tests.

摘要

本文报告了一系列针对甘蔗蟾蜍、 Rhinella marina使用的前肢和后肢偏好的测试, 协助翻身后回到正位。我们证实了该物种报告的强烈而显着的右手习惯，在某些条件下，在群体水平上超过 90% 的右手偏好。蟾蜍在包括水平和倾斜表面在内的各种条件下进行了测试，前肢有或没有机会抓住支撑物，以评估不同的前庭和本体感受输入对前后力量和方向的影响肢体偏好。一系列行为策略表明了学习效果；然而，肢体偏好的强度或方向并没有随着经验的增加而显着增加，即使在多次重新测试的蟾蜍中也是如此。肢体偏好与哺乳动物状况的比较与练习效果和已建立的肢体偏好以及与唤醒或压力相关的影响进行了讨论。与蟾蜍的惯用手代表有意或自愿偏好的预期相反，假设蟾蜍中存在侧向中央模式发生器来解释我们的测试揭示的不同形式的侧向化。