Stinkbug SICB 2024


The following 3 videos showcase the Deeplabcut tracking (top two views) and the Anipose 3D rendering (bottom screen).

Pre-autotomy tracking and 3D rendering
Post-autotomy tracking and 3D rendering. Bug missing L1 (front, left leg)

Post-autotomy tracking and 3D rendering. Bug missing R1 (front, right leg)

Stability tracking:

Graph representing the position of feet in stance during walking pre-autotomy. The approximated center of mass (COM) is represented by the black dot. The polygon turning red or blue in color represents the normal stance phase of a tripod gait. Purple polygons indicate a support area that is different than one of the two tripods. The COM falling within the polygon of support is indicative of higher stability. As seen, with all 6 legs, the COM stays within the polygon of support the vast majority of the time.
Graph representing the position of feet in stance during walking post-autotomy. The stinkbug is missing its front, left leg (L1). The approximated center of mass (COM) is represented by the black dot. The polygon turning red or blue in color represents the normal stance phase of a tripod gait. Purple polygons indicate a support area that is different than one of the two tripods. The COM falling within the polygon of support is indicative of higher stability. As seen, the COM is more likely to get outside of the support polygon when missing a leg than when the bug has all 6 legs. However, the non-typical support polygons indicate some compensation for the lost limb.

Figure 1. Missing data due to problems with calibration. Stability factor calculated as the percentage of a stride cycle that the COM falls within the polygon of support.

Figure 2. Stability factor of sbS over 1 hour post autotomy. Loss of stability after autotomy, with no significant evidence of improvement over the course of 1 hour. Note the large variability in stability after autotomy. Stability factor calculated by taking the percentage of a stride cycle that the COM falls within the polygon of support.

Yaw and Pitch:

Figure 3. Yaw per stride does not change greatly with autotomy or time, indicating no effect on heading, but some bugs were observed to walk a little sideways after autotomy.

Figure 4. Median body pitch during a stride cycle. Variation among individuals in how autotomy affects pitch . Since the front leg is missing, it would be predicted that pitch would decrease, but if it changes it increases.

Performance:

Figure 5. Median stride cycle velocity. Note that the bugs were not encouraged to go any certain speed. However, there is no significant change after autotomy or with time.

Figure 6. Distance traveled per stride does not seem to be affected significantly by autotomy.

The following animations were generated in Blender from the 3D coordinates generated by Anipose. Modeling and animation by Brian White.