Talk Andrew, Vanatheeva Sajeevan
School of Psychology, University of New England, Armidale, NSW, Australia.
PLoS One. 2024 Dec 6;19(12):e0313814. doi: 10.1371/journal.pone.0313814. eCollection 2024.
Like vertebrate animals, some invertebrates have been shown to exhibit fear- or anxiety-like behavior while in apparatus that allow choice between sheltered, darkened spaces and open, lit spaces. The behavioral mechanisms by which invertebrates accomplish this behavior, and whether those mechanisms are similar across species, has not been fully studied. Across three experiments, we investigated possible behaviors that Great Ramshorn snails (Planorbarius corneus) could use to accomplish fear behavior while in presence of the odor of a predatory fish. In experiment one, we used a light/dark preference box to demonstrate reduced preference for exposed and lit areas caused by the predator odor. In experiment two, we used an open field apparatus to demonstrate an increase in refuge-seeking (thigmotaxis, or time spent near a wall) in diffusely lit but not dark environments caused by predator odor. In the same experiment we found the snails were photokinetic (they moved faster in the light than in the dark) but we saw no effect of predator odor on photokinesis. In experiment three, we conducted a second open field study with a directional light source and found no evidence of phototaxis (movement direction with respect to light), and no effect of predator odor on phototaxis. Thus, in our studies we found evidence for refuge-seeking as a mechanism for fear-like behavior in the presence of predator odor and little evidence for perhaps more computationally simple strategies of increased photokinesis and phototaxis.
与脊椎动物一样，一些无脊椎动物在处于能在有遮蔽的黑暗空间和开阔明亮空间之间进行选择的装置中时，已被证明会表现出类似恐惧或焦虑的行为。无脊椎动物实现这种行为的行为机制，以及这些机制在不同物种间是否相似，尚未得到充分研究。在三个实验中，我们研究了大椎实螺（Planorbarius corneus）在有捕食性鱼类气味存在时可能用于实现恐惧行为的行为。在实验一中，我们使用了明暗偏好箱来证明捕食者气味会导致对暴露和明亮区域的偏好降低。在实验二中，我们使用了旷场装置来证明在捕食者气味的影响下，在漫射光但非黑暗环境中，寻求庇护（趋触性，或在墙边停留的时间）会增加。在同一实验中，我们发现蜗牛具有光动性（它们在光下比在黑暗中移动得更快），但我们没有看到捕食者气味对光动性有影响。在实验三中，我们使用定向光源进行了第二项旷场研究，没有发现趋光性（相对于光的移动方向）的证据，也没有发现捕食者气味对趋光性有影响。因此，在我们的研究中，我们发现了在捕食者气味存在时寻求庇护作为类似恐惧行为机制的证据，而对于可能更简单的增加光动性和趋光性的策略，几乎没有证据。
