Caenorhabditis elegans larvae were collected as described in the Corpse Assay. One microliter of the prey pellet was seeded onto 35 mm NGM plates. Twenty to thirty P. pacificus hermaphrodites (1- to 2-day adult) were placed on the assay plates. After 15 min of recovery, the NGM agar containing worms was removed from the dishes and placed on a glass slide. Pharyngeal pumping and tooth movement were observed at 400× magnification and recorded using a charge-coupled device (CCD) camera (Leica, MC170) at 30 fps. We could not count the number of tooth movements in 15 s, as previously described (Okumura et al. 2017 (link)), because the biting events of Ppa-nas-6 mutants rarely lasted for 15 s. Instead, we counted the number of tooth movements per 20 pumping events.