Does Maze Orientation Influence Turn Alternation Behavior in Terrestrial Isopods?
Presentation Type
Poster
Faculty Advisor
Scott Kight
Access Type
Open Access
Start Date
26-4-2024 9:45 AM
End Date
26-4-2024 10:44 AM
Description
Terrestrial isopods (Crustacea, Oniscidea) correct for deviations from a straight path by alternating the direction of subsequent turns, such as linear navigation when escaping from immediate threats. We first examined whether turning patterns were associated with desiccation in dry versus humid environmental conditions. Because terrestrial isopods breathe with gills, we anticipated that dry environmental conditions would result in an increased number of turn alternations. We studied two species of terrestrial isopods, Armadillidium vulgare and Porcellio laevis. Because A. vulgare can roll into a tight ball and P. laevis cannot, we predicted differences between species in response to desiccation. We observed animals under dry versus humid conditions, and replicated the experiment using a maze that was a mirror image of the original maze. This created a forced initial right turn in the first experiment, but a forced initial left turn in the second experiment. In the first experiment, we found that only A. vulgare in dry conditions exhibited more turn alternations than expected by chance. In the second experiment, we found that both species made more turn alterations than expected by chance in the original maze layout (first forced turn = right), but neither species made more alterations than chance expectations in the reciprocal maze (first forced turn = left). In both experiments, however, there were no differences between the two species in turn alternation behavior. These results indicate that oniscids have evolutionarily conserved navigation behavior despite significant evolutionary divergence in morphology, and further suggest that they may have lateralized navigational biases.
Does Maze Orientation Influence Turn Alternation Behavior in Terrestrial Isopods?
Terrestrial isopods (Crustacea, Oniscidea) correct for deviations from a straight path by alternating the direction of subsequent turns, such as linear navigation when escaping from immediate threats. We first examined whether turning patterns were associated with desiccation in dry versus humid environmental conditions. Because terrestrial isopods breathe with gills, we anticipated that dry environmental conditions would result in an increased number of turn alternations. We studied two species of terrestrial isopods, Armadillidium vulgare and Porcellio laevis. Because A. vulgare can roll into a tight ball and P. laevis cannot, we predicted differences between species in response to desiccation. We observed animals under dry versus humid conditions, and replicated the experiment using a maze that was a mirror image of the original maze. This created a forced initial right turn in the first experiment, but a forced initial left turn in the second experiment. In the first experiment, we found that only A. vulgare in dry conditions exhibited more turn alternations than expected by chance. In the second experiment, we found that both species made more turn alterations than expected by chance in the original maze layout (first forced turn = right), but neither species made more alterations than chance expectations in the reciprocal maze (first forced turn = left). In both experiments, however, there were no differences between the two species in turn alternation behavior. These results indicate that oniscids have evolutionarily conserved navigation behavior despite significant evolutionary divergence in morphology, and further suggest that they may have lateralized navigational biases.