Using Enclosed Y-Mazes to Assess Chemosensory Behavior in Reptiles

This method enables assessment of exploratory behavior in terrestrial vertebrates when presented with only chemical cues. It is adaptable to many species. Y-mazes provide insight into behavioral and ecological questions in vertebrates that enable researchers to determine the relevance of specific stimuli driving animal behavior.

Y-mazes are highly adaptable and widely useful to assess animal behavior, especially preference and modular behavior. Demonstrating the procedure will be Gretchen Anderson from USGS. Begin by placing new, clean scenting paper in the Y-maze that is long enough to overlap at the junction of the Y and cover the entire bottom surface.

Secure the ends of the papers near the boxes and the Y-junction with masking tape. Install the partitions to block half of the base arm. For large scenting animals, affix a heavy object that can be easily removed and cleaned behind the barrier as a brace to prevent barrier failure.

Then install the barrier at the entrance to the opposite arm. When installing the barriers, do not rip the scenting paper. Slide the acrylic top into place one section at a time and ensure that the angles meet completely.

Use clear plastic tape to cover any gaps. Attach both arm boxes to the maze by connecting the faceplates with wing nuts or padlocks and ensure that the doors are locked open. At a time of day biologically relevant to peak activity of your study species, attach the base box containing the scenting animal, keeping all movements slow and steady to minimize stress to the animal and open the door to the base box latching the door in place with both barrel bolt locks.

Remain out of the animal's view and exit the area. After three hours, note the location of the animal within the maze, as well as the ambient conditions. If the animal is in transit, wait until it enters the box.

If the animal is in any box, close and secure the box door, remove the box and then remove the animal, taking care to prevent defensive scent deposition in the box. If the animal is motionless inside the body of the maze, use visual cues to stimulate its movement into the box. If the animal stays in place, remove the arm boxes so that the acrylic top can be removed, then collect the animal manually and transfer it to a bag.

Partially disassemble the maze to allow removal of the interior partitions while taking care to avoid disturbing the scent paper and then reassemble it. If defecation occurred, collect and absorb as much as possible with clean microfiber cloths, but do not wash the area. Use slow steady movements when holding and transporting the box to minimize stress to the focal animal.

Attach the base box to the base of the Y-maze using wing nuts or padlocks. Ensure that both arm box doors are latched open, then begin the focal trial by opening and latching the base box door using barrel bolts. Remain out of the animal's view and exit the area.

A multitude of variables can be recorded and scored from Y-maze trials. The majority of studies using Y-mazes reports simple binary choice data and analyzed the results with parametric statistics, such as a binomial test. A series of statistical thresholds per study sample size are depicted here, demonstrating how many successes would need to occur for a given binomial test to yield statistically significant results.

These are mathematically derived and therefore generalizable to any Y-maze test. Throughout the duration of an experiment in which focal animals are observed, a variety of individual behaviors can be quantified. Video recordings facilitate behavioral scoring.

Temporal aspects of animal performance can also be quantified during Y-maze trials. With any studies involving animal behavior, observer bias significantly influences data collection. Therefore, observers should be blind to the treatment being tested.

The simplest way to do this is to code the video files numerically, and then randomly sort them prior to assigning them to observers. Any experimental apparatus in chemoecological studies like Y-mazes must be constructed to allow low stress, easy removal of the animal within and should be easy to disassemble for thorough cleaning and reset. Stimuli can be tested in unique combinations to determine multimodal influence of cues, such as changing contexts of cue presentation.

For example, visual and chemical cues can be presented. Although Y-mazes have been used for approximately 100 years to test reptile behavior, this approach enhances the ability to work with large and invasive species, as well as to remotely capture video data.