Landmark‐guided T‐maze learning in the wolf spiderTigrosa helluo

Abstract

Spatial learning and navigation may be acquired through idiothetic information (i.e., self‐referential movement cues) or allothetic cues (e.g., external landmarks). Animals may use specific types of landmarks to navigate known as reference frames. A reference frame is an environmental shape or boundary that provides a framework for spatial localization. Wolf spiders produce draglines of silk as they move through the environment that could serve as reference frames and may predispose spiders to use other reference frames to navigate. Using a modified water T‐maze, we recorded the ability of adult female Tigrosa helluo wolf spiders to correctly navigate toward a target goal. We measured variation in spatial learning of the target location with and without a reference frame landmark (tape marking the correct path). Females were trained over ten consecutive trials to successfully achieve the goal. Training trials were then repeated the following day for each subject for a total of 20 trials over two days. In the landmark condition, after the 20 trials, we reversed the reference frame to the incorrect arm choice to test for a decline in performance. For each trial, we measured the latency to achieve the goal and number of reversions or path retracing. Results indicate significantly shorter time to goal over subsequent trials with shorter mean latency to achieve the goal on the second day compared with the first. The landmark treatment showed significantly fewer wrong turns and path retracings than the control, and the reversal of the reference frame significantly increased the latency to achieve the goal. Wolf spiders can learn simple T‐maze navigation under our testing conditions, but learning is enhanced when reference frames are present. Landmarks are important for spider allothetic spatial navigation, and learned spatial navigation tasks are better retained over two days in the presence of reference frames.