Fig. 4: Visualizing animal and environment interaction.

A Example brightfield image showing predator prey contact between P. pacificus predator and C. elegans prey. B Example images of sequential stages of a predatory event involving the predator P. pacificus expressing RFP in the pharynx (magenta) and C. elegans prey expressing GFP in the body wall muscles (cyan) at 3.1× magnification. The scale bar corresponds to 100 µm. Arrows point to the corresponding track in (C). C Example tracks of the centerline of the predator between 45 s and 150 s of recording. Colors indicate predicted behavioral states using the model published in ref. ⁴⁹. The scale bar corresponds to 200 µm. D Ethogram showing the predicted behavioral states over time, with corresponding velocity (µm/sec), pharyngeal contractions of the predator (Hz), and prey signal. Prey signal quantifies GFP fluorescence from C. elegans prey expressed in the body wall muscles detected in front of the predator’s mouth opening. Signal increases indicate prey contact during biting and feeding. Arrows point to the corresponding track in (C). E Stacked ethograms of n = 43 tracks, N = 8 predators aligned at the onset of predatory biting at t = 0. F Prey signal (mean ±  s.e.m. in %) of the ethograms shown in (E), excluding those with the mode of predatory biting or predatory feeding before bite onset, n = 17, N = 7. Prey signal was detected as in (D), but normalized to the signal within −15 to −5 s before bite onset at t = 0. Statistics performed with an upper-tailed paired t-test comparing time ranges −15 to −5 and 0 to 15 s, *p = 0.049.